Variable travel valve apparatus for an internal combustion engine

An apparatus includes a valve and an actuator. The valve has a portion movably disposed within a valve pocket defined by a cylinder head of an engine. The valve is configured to move relative to the cylinder head a distance between a closed position and an opened position. The portion of the valve defines a flow opening that is in fluid communication with a cylinder of an engine when the valve is in the opened position. The actuator is configured to selectively vary the distance between the closed position and the opened position.

BACKGROUND

The embodiments described herein relate to an apparatus for controlling gas exchange processes in a fluid processing machine, and more particularly to a valve and cylinder head assembly for an internal combustion engine.

Many fluid processing machines, such as, for example, internal combustion engines, compressors, and the like, require accurate and efficient gas exchange processes to ensure optimal performance. For example, during the intake stroke of an internal combustion engine, a predetermined amount of air and fuel must be supplied to the combustion chamber at a predetermined time in the operating cycle of the engine. The combustion chamber then must be sealed during the combustion event to prevent inefficient operation and/or damage to various components in the engine. During the exhaust stroke, the burned gases in the combustion chamber must be efficiently evacuated from the combustion chamber.

Some known internal combustion engines use poppet valves to control the flow of gas into and out of the combustion chamber. Known poppet valves are reciprocating valves that include an elongated stem and a broadened sealing head. In use, known poppet valves open inwardly towards the combustion chamber such that the sealing head is spaced apart from a valve seat, thereby creating a flow path into or out of the combustion chamber when the valve is in the opened position. The sealing head can include an angled surface configured to contact a corresponding surface on the valve seat when the valve is in the closed position to effectively seal the combustion chamber.

The enlarged sealing head of known poppet valves, however, obstructs the flow path of the gas coming into or leaving the combustion cylinder, which can result in inefficiencies in the gas exchange process. Moreover, the enlarged sealing head can also produce vortices and other undesirable turbulence within the incoming air, which can negatively impact the combustion event. To minimize such effects, some known poppet valves are configured to travel a relatively large distance between the closed position and the opened position. Increasing the valve lift, however, results in higher parasitic losses, greater wear on the valve train, greater chance of valve-to-piston contact during engine operation, and the like.

Because the sealing head of known poppet valves extends into the combustion chamber, they are exposed to the extreme pressures and temperatures of engine combustion, which increases the likelihood that the valves will fail or leak. Exposure to combustion conditions can cause, for example, greater thermal expansion, detrimental carbon deposit build-up and the like. Moreover, such an arrangement is not conducive to servicing and/or replacing valves. In many instances, for example, the cylinder head must be removed to service or replace the valves.

To reduce the likelihood of leakage, known poppet valves are biased in the closed position using relatively stiff springs. Thus, known poppet valves are often actuated using a camshaft to produce the high forces necessary to open the valve. Known camshaft-based actuation systems, however, have limited flexibility to change the valve travel (or lift), timing and/or duration of the valve event as a function of engine operating conditions. For example, although some known camshaft-based actuation systems can change the valve opening or duration, such changes are limited because the valve events are dependent on the rotational position of the camshaft and/or the engine crankshaft. Accordingly, the valve events (i.e., the timing, duration and/or travel) are not optimized for each engine operating condition (e.g., low idle, high speed, full load, etc.), but are rather selected as a compromise that provides the desired overall performance.

Some known poppet valves are actuated using electronic actuators. Such solenoid-based actuation systems, however, often require multiple springs and/or solenoids to overcome the force of the biasing spring. Moreover, solenoid-based actuation systems require relatively high power to actuate the valves against the force of the biasing spring.

Thus, a need exists for an improved valve actuation system for an internal combustion engine and like systems and devices.

SUMMARY

Gas exchange valves and methods are described herein. In some embodiments, an apparatus includes a valve and an actuator. The valve has a portion movably disposed within a valve pocket defined by a cylinder head of an engine. The valve is configured to move relative to the cylinder head a distance between a closed position and an opened position. The portion of the valve defines a flow opening that is in fluid communication with a cylinder of an engine when the valve is in the opened position. The actuator is configured to selectively vary the distance between the closed position and the opened position.

DETAILED DESCRIPTION

In some embodiments, an apparatus includes a valve and an actuator. The valve has a portion movably disposed within a valve pocket defined by a cylinder head of an engine. The valve is configured to move relative to the cylinder head a distance between a closed position and an opened position. The portion of the valve defines a flow opening that is in fluid communication with a cylinder of an engine when the valve is in the opened position. The actuator is configured to selectively vary the distance between the closed position and the opened position.

In some embodiments, an apparatus includes a valve and an actuator. The valve has a portion movably disposed within a flow passageway defined by a cylinder head of an engine. The valve is configured to move relative to the cylinder head a distance between a closed position and an opened position. The valve is configured to move independent of the rotation of a crankshaft of the engine. The valve is disposed outside of a cylinder of the engine when the valve is in the opened position. The actuator is configured to selectively vary the distance between the closed position and the opened position.

In some embodiments, an apparatus includes a valve, a biasing member and an actuator. The valve has a portion movably disposed within a flow passageway defined by a cylinder head of an engine. The valve is configured to move relative to the cylinder head a distance between a closed position and an opened position. The valve is configured to move independent of the rotation of a crankshaft of the engine. The biasing member, which can be, for example, a spring, is configured to bias the valve towards the closed position. The biasing member is configured to exert a force on the valve when the valve is in the closed position. The actuator is configured to selectively vary the distance between the closed position and the opened position. The force exerted by the biasing member on the valve is maintained at a substantially constant value when the valve is in the closed position. Similarly stated, the actuator is configured to selectively vary the valve travel without changing the force exerted by the biasing member on the valve when the valve is in the closed position.

FIGS. 1 and 2are schematic illustrations of a cylinder head assembly130according to an embodiment in a first and second configuration, respectively. The cylinder head assembly130includes a cylinder head132and a valve member160. The cylinder head132has an interior surface134that defines a valve pocket138having a longitudinal axis Lp. The valve member160has tapered portion162defining two flow passages168and having a longitudinal axis Lv. The tapered portion162includes two sealing portions172, each of which is disposed adjacent one of the flow passages168. The tapered portion162includes a first side surface164and a second side surface165. The second side surface165of the tapered portion162is angularly offset from the longitudinal axis Lv by a taper angle Θ, thereby producing the taper of the tapered portion162. Although the first side surface164is shown as being substantially parallel to the longitudinal axis Lv, thereby resulting in an asymmetrical tapered portion162, in some embodiments, the first side surface164is angularly offset such that the tapered portion162is symmetrical about the longitudinal axis Lv. Although the tapered portion162is shown as including a linear taper defining the taper angle Θ, in some embodiments the tapered portion162can include a non-linear taper.

The valve member160is reciprocatably disposed within the valve pocket138such that the tapered portion162of the valve member160can be moved along the longitudinal axis Lv of the tapered portion162within the valve pocket138. In use, the cylinder head assembly130can be placed in a first configuration (FIG. 1) and a second configuration (FIG. 2). As illustrated inFIG. 1, when in the first configuration, the valve member160is in a first position in which the sealing portions172are disposed apart from the interior surface134of the cylinder head132such that each flow passage168is in fluid communication with an area137outside of the cylinder head132. As illustrated inFIG. 2, the cylinder head assembly132is placed into the second configuration by moving the valve member160inwardly along the longitudinal axis Lv in the direction indicated by the arrow labeled A. When in the second configuration, the sealing portions172are in contact with a portion of the interior surface134of the cylinder head132such that each flow passage168is fluidically isolated from the area137outside of the cylinder head132.

Although the entire valve member160is shown as being tapered, in some embodiments, only a portion of the valve member is tapered. For example, as will be discussed herein, in some embodiments, a valve member can include one or more non-tapered portions. In other embodiments, a valve member can include multiple tapered portions.

Although the flow passages168are shown as being substantially normal to the longitudinal axis Lv of the valve member160, in some embodiments, the flow passages168can be angularly offset from the longitudinal axis Lv. Moreover, in some embodiments, the longitudinal axis Lv of the valve member160need not be coincident with the longitudinal axis Lp of the valve pocket138. For example, in some embodiments, the longitudinal axis of the valve member can be offset from and parallel to the longitudinal axis of the valve pocket. In other embodiments, the longitudinal axis of the valve can be disposed at an angle to the longitudinal axis of the valve pocket.

As illustrated, the longitudinal axis Lv of the tapered portion162is coincident with the longitudinal axis of the valve member. Accordingly, throughout the specification, the longitudinal axis of the tapered portion may be referred to as the longitudinal axis of the valve member and vice versa. In some embodiments, however, the longitudinal axis of the tapered portion can be offset from the longitudinal axis of the valve member. For example, in some embodiments, the first stem portion and/or the second stem portion as described below can be angularly offset from the tapered portion such that the longitudinal axis of the valve member is offset from the longitudinal axis of the tapered portion.

Although the cylinder head assembly130is illustrated as having a first configuration (i.e., an opened configuration) in which the flow passages168are in fluid communication with an area137outside of the cylinder head132and second configuration (i.e., a closed configuration) in which the flow passages168are fluidically isolated from the area137outside of the cylinder head132, in some embodiments the first configuration can be the closed configuration and the second configuration can be the opened configuration. In other embodiments, the cylinder head assembly130can have more than two configurations. For example, in some embodiments, a cylinder head assembly can have multiple open configurations, such as, for example, a partially opened configuration and a fully opened configuration.

FIGS. 3 and 4are schematic illustrations of a portion of an engine200according to an embodiment in a first and second configuration, respectively. The engine200includes a cylinder head assembly230, a cylinder203and a gas manifold210. The cylinder203is coupled to a first surface235of the cylinder head assembly230and can be, for example, a combustion cylinder defined by an engine block (not shown). The gas manifold210is coupled to a second surface236of the cylinder head assembly230and can be, for example an intake manifold or an exhaust manifold. Although the first surface235and the second surface236are shown as being parallel to and disposed on opposite sides of the cylinder head232from each other, in other embodiments, the first surface and the second surface can be adjacent each other. In yet other embodiments, the gas manifold and the cylinder can be coupled to the same surface of the cylinder head.

The cylinder head assembly230includes a cylinder head232and a valve member260. The cylinder head232has an interior surface234that defines a valve pocket238having a longitudinal axis Lp. The cylinder head232also defines two cylinder flow passages248and two gas manifold flow passages244. Each of the cylinder flow passages248is in fluid communication with the cylinder203and the valve pocket238. Similarly, each of the gas manifold flow passages244is in fluid communication with the gas manifold210and the valve pocket238. Although each of the cylinder flow passages248is shown as being fluidically isolated from the other cylinder flow passage248, in other embodiments, the cylinder flow passages248can be in fluid communication with each other. Similarly, although each of the gas manifold flow passages244is shown as being fluidically isolated from the other gas manifold flow passage244, in other embodiments, the gas manifold flow passages244can be in fluid communication with each other.

The valve member260has a tapered portion262having a longitudinal axis Lv and a taper angle Θ with respect to the longitudinal axis Lv. The tapered portion262defines two flow passages268and includes two sealing portions272, each of which is disposed adjacent one of the flow passages268. Although shown as being an asymmetrical taper in a single dimension, in some embodiments the tapered portion can be symmetrically tapered about the longitudinal axis Lv. In other embodiments, as discussed in more detail herein, the tapered portion can be tapered in two dimensions about the longitudinal axis Lv.

The valve member260is disposed within the valve pocket238such that the tapered portion262of the valve member260can be moved along its longitudinal axis Lv within the valve pocket238. In use, the engine200can be placed in a first configuration (FIG. 3) and a second configuration (FIG. 4). As illustrated inFIG. 3, when in the first configuration, the valve member260is in a first position in which each flow passage268is in fluid communication with one of the cylinder flow passages248and one of the gas manifold flow passages244. In this manner, the gas manifold210is in fluid communication with the cylinder203. Although the flow passages268are shown as being aligned with the cylinder flow passages248and the gas manifold flow passages244when the engine is in the first configuration, in other embodiments the flow passages268need not be directly aligned. In other words, the flow passages268,248,24may be offset when the engine200is in the first configuration, but the gas manifold210is still in fluid communication with the cylinder203.

As illustrated inFIG. 4, when the engine200is in the second configuration, the valve member260is in a second position, axially offset from the first position in the direction indicated by the arrow labeled B. In the second configuration, the sealing portions272are in contact with a portion of the interior surface234of the cylinder head232such that each flow passage268is fluidically isolated from the cylinder flow passages248. In this manner, the cylinder203is fluidically isolated from the gas manifold210.

FIG. 5is a cross-sectional front view of a portion of an engine300including a cylinder head assembly330in a first configuration according to an embodiment.FIG. 6is a cross-sectional front view of the cylinder head assembly330in a second configuration. The engine300includes an engine block302and a cylinder head assembly330coupled to the engine block302. The engine block302defines a cylinder303having a longitudinal axis Lc. A piston304is disposed within the cylinder303such that it can reciprocate along the longitudinal axis Lc of the cylinder303. The piston304is coupled by a connecting rod306to a crankshaft308having an offset throw307such that as the piston reciprocates within the cylinder303, the crankshaft308is rotated about its longitudinal axis (not shown). In this manner, the reciprocating motion of the piston304can be converted into a rotational motion.

A first surface335of the cylinder head assembly330is coupled to the engine block302such that a portion of the first surface335covers the upper portion of the cylinder303thereby forming a combustion chamber309. Although the portion of the first surface335covering the cylinder303is shown as being curved and angularly offset from the top surface of the piston, in some embodiments, because the cylinder head assembly330does not include valves that protrude into the combustion chamber, the surface of the cylinder head assembly forming part of the combustion chamber can have any suitable geometric design. For example, in some embodiments, the surface of the cylinder head assembly forming part of the combustion chamber can be flat and parallel to the top surface of the piston. In other embodiments, the surface of the cylinder head assembly forming part of the combustion chamber can be curved to form a hemispherical combustion chamber, a pent-roof combustion chamber or the like.

A gas manifold310defining an interior area312is coupled to a second surface336of the cylinder head assembly330such that the interior area312of the gas manifold310is in fluid communication with a portion of the second surface336. As described in detail herein, this arrangement allows a gas, such as, for example air or combustion by-products, to be transported into or out of the cylinder303via the cylinder head assembly330and the gas manifold310. Although shown as including a single gas manifold310, in some embodiments, an engine can include two or more gas manifolds. For example, in some embodiments an engine can include an intake manifold configured to supply air and/or an air-fuel mixture to the cylinder head and an exhaust manifold configured to transport exhaust gases away from the cylinder head.

Moreover, as shown, in some embodiments the first surface335can be opposite the second surface336, such that the flow of gas into and/or out of the cylinder303can occur along a substantially straight line. In such an arrangement, a fuel injector (not shown) can be disposed in an intake manifold (not shown) directly above the cylinder flow passages348. In this manner, the injected fuel can be conveyed into the cylinder303without being subjected to a series of bends. Eliminating bends along the fuel path can reduce fuel impingement and/or wall wetting, thereby leading to more efficient engine performance, such as, for example, improved transient response.

The cylinder head assembly330includes a cylinder head332and a valve member360. The cylinder head332has an interior surface334that defines a valve pocket338having a longitudinal axis Lp. The cylinder head332also defines four cylinder flow passages348and four gas manifold flow passages344. Each of the cylinder flow passages348is adjacent the first surface335of the cylinder head332and is in fluid communication with the cylinder303and the valve pocket338. Similarly, each of the gas manifold flow passages344is adjacent the second surface336of the cylinder head332and is in fluid communication with the gas manifold310and the valve pocket338. Each of the cylinder flow passages348is aligned with a corresponding gas manifold flow passage344. In this arrangement, when the cylinder head assembly330is in the first (or opened) configuration (see, e.g.,FIGS. 5 and 7), the gas manifold310is in fluid communication with the cylinder303. Conversely, when the cylinder head assembly330is in a second (or closed) configuration (see, e.g.,FIGS. 6 and 8), the gas manifold310is fluidically isolated from the cylinder303.

The valve member360has tapered portion362, a first stem portion376and a second stem portion377. The first stem portion376is coupled to an end of the tapered portion362of the valve member360and is configured to engage a valve lobe315of a camshaft314. The second stem portion377is coupled to an end of the tapered portion362opposite from the first stem portion376and is configured to engage a spring318. A portion of the spring318is contained within an end plate323, which is removably coupled to the cylinder head332such that it compresses the spring318against the second stem portion377thereby biasing the valve member360in a direction indicated by the arrow D inFIG. 6.

The tapered portion362of the valve member360defines four flow passages368therethrough. The tapered portion includes eight sealing portions372(see, e.g.,FIGS. 10,11and13), each of which is disposed adjacent one of the flow passages368and extends continuously around the perimeter of an outer surface363of the tapered portion362. The valve member360is disposed within the valve pocket338such that the tapered portion362of the valve member360can be moved along a longitudinal axis Lv of the valve member360within the valve pocket338. In some embodiments, the valve pocket338includes a surface352configured to engage a corresponding surface380on the valve member360to limit the range of motion of the valve member360within the valve pocket338.

In use, when the camshaft314is rotated such that the eccentric portion of the valve lobe315is in contact with the first stem376of the valve member360, the force exerted by the valve lobe315on the valve member360is sufficient to overcome the force exerted by the spring318on the valve member360. Accordingly, as shown inFIG. 5, the valve member360is moved along its longitudinal axis Lv within the valve pocket338in the direction of the arrow C, into a first position, thereby placing the cylinder head assembly330in the opened configuration. When in the opened configuration, the valve member360is positioned within the valve pocket338such that each flow passage368is aligned with and in fluid communication with one of the cylinder flow passages348and one of the gas manifold flow passages344. In this manner, the gas manifold310is in fluid communication with the cylinder303, along the flow path indicated by the arrow labeled E inFIG. 7.

When the camshaft314is rotated such that the eccentric portion of the camshaft lobe315is not in contact with the first stem376of the valve member360, the force exerted by the spring318is sufficient to move the valve member360in the direction of the arrow D, into a second position, axially offset from the first position, thereby placing the cylinder head assembly330in the closed configuration (seeFIG. 6). When in the closed configuration, each flow passage368is offset from the corresponding cylinder flow passage348and gas manifold flow passage344. Moreover, as shown inFIG. 8, when in the closed configuration, each of the sealing portions372is in contact with a portion of the interior surface334of the cylinder head332such that each flow passage368is fluidically isolated from the cylinder flow passages348. In this manner, the cylinder303is fluidically isolated from the gas manifold310.

Although the cylinder head assembly330is described as being configured to fluidically isolate the flow passages368from the cylinder flow passages348when in the closed configuration, in some embodiments, the sealing portions372can be configured to contact a portion of the interior surface334of the cylinder head332such that each flow passage368is fluidically isolated from the cylinder head flow passages348and the gas manifold flow passages344. In other embodiments, the sealing portions372can be configured to contact a portion of the interior surface334of the cylinder head332such that each flow passage368is fluidically isolated only from the gas manifold flow passages344.

Although each of the cylinder flow passages348is shown being fluidically isolated from the other cylinder flow passage348, in some embodiments, the cylinder flow passages348can be in fluid communication with each other. Similarly, although each of the gas manifold flow passages344is shown being fluidically isolated from the other gas manifold flow passages344, in other embodiments, the gas manifold flow passages344can be in fluid communication with each other.

Although the longitudinal axis Lc of the cylinder303is shown as being substantially normal to the longitudinal axis Lp of the valve pocket338and the longitudinal axis Lv of the valve360, in some embodiments, the longitudinal axis of the cylinder can be offset from the longitudinal axis of the valve pocket and/or the longitudinal axis of the valve member by an angle other than 90 degrees. In yet other embodiments, the longitudinal axis of the cylinder can be substantially parallel to the longitudinal axis of the valve pocket and/or the longitudinal axis of the valve member. Similarly, as described above, the longitudinal axis Lv of the valve member360need not be coincident with or parallel to the longitudinal axis Lp of the valve pocket338.

In some embodiments, the camshaft314is disposed within a portion of the cylinder head332. An end plate322is removably coupled to the cylinder head332to allow access to the camshaft314and the first stem portion376for assembly, repair and/or adjustment. In other embodiments, the camshaft is disposed within a separate cam box (not shown) that is removably coupled to the cylinder head. Similarly, the end plate323is removably coupled to the cylinder head332to allow access to the spring318and/or the valve member360for assembly, repair, replacement and/or adjustment.

In some embodiments, the spring318is a coil spring configured to exert a force on the valve member360thereby ensuring that the sealing portions372remain in contact with the interior surface334when the cylinder head assembly330is in the closed configuration. The spring318can be constructed from any suitable material, such as, for example, a stainless steel spring wire, and can be fabricated to produce a suitable biasing force. In some embodiments, however, a cylinder head assembly can include any suitable biasing member to ensure that that the sealing portions372remain in contact with the interior surface334when the cylinder head assembly330is in the closed configuration. For example, in some embodiments, a cylinder head assembly can include a cantilever spring, a Belleville spring, a leaf spring and the like. In other embodiments, a cylinder head assembly can include an elastic member configured to exert a biasing force on the valve member. In yet other embodiments, a cylinder head assembly can include an actuator, such as a pneumatic actuator, a hydraulic actuator, an electronic actuator and/or the like, configured to exert a biasing force on the valve member.

Although the first stem portion376is shown and described as being in direct contact with the valve lobe315of the camshaft314, in some embodiments, an engine and/or cylinder head assembly can include a member configured to maintain a predetermined valve lash setting, such as for example, an adjustable tappet, disposed between the camshaft and the first stem portion. In other embodiments, an engine and/or cylinder head assembly can include a hydraulic lifter disposed between the camshaft and the first stem portion to ensure that the valve member is in constant contact with the camshaft. In yet other embodiments, an engine and/or a cylinder head assembly can include a follower member, such as for example, a roller follower disposed between the first stem portion. Similarly, in some embodiments, an engine can include one or more components disposed adjacent the spring. For example, in some embodiments, the second stem portion can include a spring retainer, such as for example, a pocket, a clip, or the like. In other embodiments, a valve rotator can be disposed adjacent the spring.

Although the cylinder head332is shown and described as being a separate component coupled to the engine block302, in some embodiments, the cylinder head332and the engine block302can be monolithically fabricated, thereby eliminating the need for a cylinder head gasket and cylinder head mounting bolts. In some embodiments, for example, the engine block and the cylinder head can be cast using a single mold and subsequently machined to include the cylinders, valve pockets and the like. Moreover, as described above, the valve members can be installed and/or serviced by removing the end plate.

Although the engine300is shown and described as including a single cylinder, in some embodiments, an engine can include any number of cylinders in any arrangement. For example, in some embodiments, an engine can include any number of cylinders in an in-line arrangement. In other embodiments, any number of cylinders can be arranged in a vee configuration, an opposed configuration or a radial configuration.

Similarly, the engine300can employ any suitable thermodynamic cycle. Such engine types can include, for example, Diesel engines, spark ignition engines, homogeneous charge compression ignition (HCCI) engines, two-stroke engines and/or four stroke engines. Moreover, the engine300can include any suitable type of fuel injection system, such as, for example, multi-port fuel injection, direct injection into the cylinder, carburetion, and the like.

Although the cylinder head assembly330is shown and described above as being devoid of mounting holes, a spark plug, and the like, in some embodiments, a cylinder head assembly includes mounting holes, spark plugs, cooling passages, oil drillings and the like.

Although the cylinder head assembly330is shown and described above with reference to a single valve360and a single gas manifold310, in some embodiments, a cylinder head assembly includes multiple valves and gas manifolds. For example,FIG. 9illustrates a top view of the cylinder head assembly330including an intake valve member360I and an exhaust valve member360E. As illustrated, the cylinder head332defines an intake valve pocket3381, within which the intake valve member360I is disposed, and an exhaust valve pocket338E, within which the exhaust valve member360E is disposed. Similar to the arrangement described above, the cylinder head332also defines four intake manifold flow passages3441, four exhaust manifold flow passages344E and the corresponding cylinder flow passages (not shown inFIG. 9). Each of the intake manifold flow passages3441is adjacent the second surface336of the cylinder head332and is in fluid communication with an intake manifold (not shown) and the intake valve pocket3381. Similarly, each of the exhaust manifold flow passages344E is adjacent the second surface336of the cylinder head332and is in fluid communication with an exhaust manifold (not shown) and the exhaust valve pocket338E.

The operation of the intake valve member360I and the exhaust valve member360E is similar to that of the valve member360described above in that each has a first (or opened) position and a second (or closed) position. InFIG. 9, the intake valve member360I is shown in the opened position, in which each flow passage3681defined by the tapered portion3621of the intake valve member360I is aligned with its corresponding intake manifold flow passage3441and cylinder flow passage (not shown). In this manner, the intake manifold (not shown) is in fluid communication with the cylinder303, thereby allowing a charge of air to be conveyed from the intake manifold into the cylinder303. Conversely, the exhaust valve member360E is shown in the closed position in which each flow passage368E defined by the tapered portion362E of the exhaust valve member360E is offset from its corresponding exhaust manifold flow passage344E and cylinder flow passage (not shown). Moreover, each sealing portion (not shown inFIG. 9) defined by the exhaust valve member360E is in contact with a portion of the interior surface of the exhaust valve pocket338E such that each flow passage368E is fluidically isolated from the cylinder flow passages (not shown). In this manner, the cylinder303is fluidically isolated from the exhaust manifold (not shown).

The cylinder head assembly330can have many different configurations corresponding to the various combinations of the positions of the valve members360I,360E as they move between their respective first and second positions. One possible configuration includes an intake configuration in which, as shown inFIG. 9, the intake valve member360I is in the opened position and the exhaust valve member360E is in the closed position. Another possible configuration includes a combustion configuration in which both valves are in their closed positions. Yet another possible configuration includes an exhaust configuration in which the intake valve member360I is in the closed position and the exhaust valve member360E is in the opened position. Yet another possible configuration is an overlap configuration in which both valves are in their opened positions.

Similar to the operation described above, the intake valve member360I and the exhaust valve member360E are moved by a camshaft314that includes an intake valve lobe315I and an exhaust valve lobe315E. As shown, the intake valve member360I and the exhaust valve member360E are each biased in the closed position by springs318I,318E, respectively. Although the intake valve lobe315I and the exhaust valve lobe315E are illustrated as being disposed on a single camshaft314, in some embodiments, an engine can include separate camshafts to move the intake and exhaust valve members. In other embodiments, as discussed herein, the intake valve member360I and/or the exhaust valve member360E can be moved by an suitable means, such as, for example, an electronic solenoid, a stepper motor, a hydraulic actuator, a pneumatic actuator, a piezo-electric actuator or the like. In yet other embodiments, the intake valve member360I and/or the exhaust valve member360E are not maintained in the closed position by a spring, but rather include mechanisms similar to those described above for moving the valve. For example, in some embodiments, a first stem of a valve member can engage a camshaft valve lobe and the second stem of the valve member can engage a solenoid configured to bias the valve member.

FIGS. 10-13show a top view, a front view, a side cross-sectional view and a perspective view of the valve member360, respectively. As described above, the valve member has tapered portion362, a first stem portion376and a second stem portion377. The tapered portion362of the valve member360defines four flow passages368. Each flow passage368extends through the tapered portion362and includes a first opening369and a second opening370. In the illustrated embodiment, the flow passages368are spaced apart by a distance S along the longitudinal axis Lv of the tapered portion362. The distance S corresponds to the distance that the tapered portion362moves within the valve pocket338when transitioning from the first (opened configuration) to the second (closed) configuration. Accordingly, the travel (or stroke) of the valve member can be reduced by spacing the flow passages368closer together. In some embodiments, the distance S can be between 2.3 mm and 4.2 mm (0.090 in. and 0.166 in.). In other embodiments, the distance S can be less than 2.3 mm (0.090 in.) or greater than 4.2 mm (0.166 in.). Although illustrated as having a constant spacing S, in some embodiments, the flow passages are each separated by a different distance. As discussed in more detail herein, reducing the stroke of the valve member can result in several improvements in engine performance, such as, for example, reduced parasitic losses, allowing the use of weaker valve springs, and the like.

Although the tapered portion362is shown as defining four flow passages having a long, narrow shape, in some embodiments a valve member can define any number of flow passages having any suitable shape and size. For example, in some embodiments, a valve member can include eight flow passages configured to have approximately the same cumulative flow area (as taken along a plane normal to the longitudinal axis Lf of the flow passages) as that of a valve member having four larger flow passages. In such an embodiment, the flow passages can be arranged such that the spacing between the flow passages of the “eight passage valve member” is approximately half that of the of the spacing between the flow passages of the “four passage valve member.” As such, the stroke of the “eight passage valve member” is approximately half that of the “four passage valve member,” thereby resulting in an arrangement that provides substantially the same flow area while requiring the valve member to move only approximately half the distance.

Each flow passage368need not have the same shape and/or size as the other flow passages368. Rather, as shown, the size of the flow passages can decrease with the taper of the tapered portion362of the valve member360. In this manner, the valve member360can be configured to maximize the cumulative flow area, thereby resulting in more efficient engine operation. Moreover, in some embodiments, the shape and/or size of the flow passages368can vary along the longitudinal axis Lf. For example, in some embodiments, the flow passages can have a lead-in chamfer or taper along the longitudinal axis Lf.

Similarly, each of the manifold flow passages344and each of the cylinder flow passages348need not have the same shape and/or size as the other manifold flow passages344and each of the cylinder flow passages348, respectively. Moreover, in some embodiments, the shape and/or size of the manifold flow passages344and/or the cylinder flow passages348can vary along their respective longitudinal axes. For example, in some embodiments, the manifold flow passages can have a lead in chamfer or taper along their longitudinal axes. In other embodiments, the cylinder flow passages can have a lead-in chamfer or taper along their longitudinal axes.

Although the longitudinal axis Lf of the flow passages368is shown inFIG. 12as being substantially normal to the longitudinal axis Lv of the valve member360, in some embodiments the longitudinal axis Lf of the flow passages368can be angularly offset from the longitudinal axis Lv of the valve member360by an angle other than 90 degrees. Moreover, as discussed in more detail herein, in some embodiments, the longitudinal axis and/or the centerline of one flow passage need not be parallel to the longitudinal axis of another flow passage.

As previously discussed with reference toFIG. 5, the valve member360includes a surface380configured to engage a corresponding surface352within the valve pocket338to limit the range of motion of the valve member360within the valve pocket338. Although the surface380is illustrated as being a shoulder-like surface disposed adjacent the second stem portion377, in some embodiments, the surface380can have any suitable geometry and can be disposed anywhere along the valve member360. For example, in some embodiments, a valve member can have a surface disposed on the first stem portion, the surface being configured to limit the longitudinal motion of the valve member. In other embodiments, a valve member can have a flattened surface disposed on one of the stem portions, the flattened surface being configured to limit the rotational motion of the valve member. In yet other embodiments, as illustrated inFIG. 37, the valve member360can be aligned using an alignment key398configured to be disposed within a mating keyway399.

As shown inFIG. 10, which illustrates a top view of the valve member360, the first opposing side surfaces364of the tapered portion362are angularly offset from each other by a first taper angle Θ. Similarly, as shown inFIG. 11, which presents a front view of the valve member360, the second opposing side surfaces365of the tapered portion362are angularly offset from each other by an angle α. In this manner, the tapered portion362of the valve member360is tapered in two dimensions.

Said another way, the tapered portion362of the valve member360has a width W measured along a first axis Y that is normal to the longitudinal axis Lv. Similarly, the tapered portion362has a thickness T (not to be confused with the wall thickness of any portion of the valve member) measured along a second axis Z that is normal to both the longitudinal axis Lv and the first axis Y. The tapered portion362has a two-dimensional taper characterized by a linear change in the width W and a linear change in the thickness T. As shown inFIG. 10, the width of the tapered portion362increases from a value of W1at one end of the tapered portion362to a value of W2at the opposite end of the tapered portion362. The change in width along the longitudinal axis Lv defines the first taper angle Θ. Similarly, as illustrated inFIG. 11, the thickness of the tapered portion362increases from a value of T1at one end of the tapered portion362to a value of T2at the opposite end of the tapered portion362. The change in thickness along the longitudinal axis Lv defines the second taper angle α.

In the illustrated embodiment, the first taper angle Θ and the second taper angle α are each between 2 and 10 degrees. In some embodiments, the first taper angle Θ is the same as the second taper angle α. In other embodiments, the first taper angle Θ is different from the second taper angle α. Selection of the taper angles can affect the size of the valve member and the nature of the seal formed by the sealing portions372and the interior surface334of the cylinder head332. In some embodiments, for example, the taper angles Θ, α can be as high as 90 degrees. In other embodiments, the taper angles Θ, α can be as low as 1 degree. In yet other embodiments, as discussed in more detail herein, a valve member can be devoid of a tapered portion (i.e., a taper angle of zero degrees).

Although the tapered portion362is shown and described as having a single, linear taper, in some embodiments a valve member can include a tapered portion having a curved taper. In other embodiments, as discussed in more detail herein, a valve member can have a tapered portion having multiple tapers. Moreover, although the side surfaces164,165are shown as being angularly offset substantially symmetrical to the longitudinal axis Lv, in some embodiments, the side surfaces can be angularly offset in an asymmetrical fashion.

As shown inFIGS. 10,11and13, the tapered portion362includes eight sealing portions372, each extending continuously around the perimeter of the outer surface363of the tapered portion362. The sealing portions372are arranged such that two of the sealing portions372are disposed adjacent each flow passage368. In this manner, as shown in FIG.8, when the cylinder head assembly330is in the closed position each of the sealing portions372is in contact with a portion of the interior surface334of the cylinder head332such that each flow passage368is fluidically isolated from the each cylinder flow passage348and/or each gas manifold flow passage344. Conversely, when the cylinder head assembly330is in the opened position each of the sealing portions372is disposed apart from the interior surface334of the cylinder head332such that each flow passage368is in fluid communication with the corresponding cylinder flow passages348and the corresponding gas manifold flow passages344.

Although the sealing portions372are shown and described as extending around the perimeter of the outer surface363substantially normal to the longitudinal axis Lv of the valve member360, in some embodiments, the sealing portions can be at any angular relation to the longitudinal axis Lv. Moreover, in some embodiments, the sealing portions372can be angularly offset from each other.

Although the sealing portions372are shown and described as being a locus of points continuously extending around the perimeter of the outer surface363of the tapered portion362in a linear fashion when viewed in a plane parallel to the longitudinal axis Lv and the first axis Y (i.e.,FIG. 10), in some embodiments, the sealing portions can continuously extend around the outer surface in a non-linear fashion. For example, in some embodiments, the sealing portions, when viewed in a plane parallel to the longitudinal axis Lv and the first axis Y, can be curved. In other embodiments, for example, as shown inFIG. 14, the sealing portions can be two-dimensional.FIG. 14shows a valve member460having a tapered portion472, a first stem portion476and a second stem portion477. As described above, the tapered portion includes four flow passages468therethrough. The tapered portion also includes two sealing portions472disposed about each flow passage468and extending continuously around the perimeter of the outer surface463of the tapered portion462(for clarity, only two sealing portions472are shown). In contrast to the sealing portions372described above, the sealing portions472have a width X as measured along the longitudinal axis Lv of the valve member460.

As illustrated inFIG. 12, the tapered portion362has an elliptical cross-section, which can allow for both a sufficient taper and flow passages of sufficient size. In other embodiments, however, the tapered portion can have any suitable cross-sectional shape, such as, for example, a circular cross-section, a rectangular cross-section and the like.

As shown inFIGS. 10-13, the valve member360is monolithically formed to include the first stem portion376, the second stem portion377and the tapered portion362. In other embodiments, however, the valve member includes separate components coupled together to form the first stem portion, the second stem portion and the tapered portion. In yet other embodiments, the valve member does not include a first stem portion and/or a second stem portion. For example, in some embodiments, a cylinder head assembly includes a separate component disposed within the valve pocket and configured to engage a valve lobe of a camshaft and a portion of a valve member such that a force can be directly transmitted from the camshaft to the valve member. Similarly, in some embodiments, a cylinder head assembly includes a separate component disposed within the valve pocket and configured to engage a spring and a portion of a valve member such that a force can be transmitted from the spring to the valve member.

Although the sealing portions372and the outer surface363are shown and described as being monolithically constructed, in some embodiments, the sealing portions can be separate components coupled to the outer surface of the tapered portion. For example, in some embodiments, the sealing portions can be sealing rings that are held into mating grooves on the outer surface of the tapered portion by a friction fit. In other embodiments, the sealing portions are separate components that are bonded to the outer surface of the tapered portion by any suitable means, such as, for example, chemical bonding, thermal bonding and the like. In yet other embodiments, the sealing portions include a coating applied to the outer surface of the tapered portion by any suitable manner, such as for example, electrostatic spray deposition, chemical vapor deposition, physical vapor deposition, ionic exchange coating, and the like.

The valve member360can be fabricated from any suitable material or combination of materials. For example, in some embodiments, the tapered portion can be fabricated from a first material, the stem portions can be fabricated from a second material different from the first material and the sealing portions, to the extent that they are separately formed, can be fabricated from a third material different from the first two materials. In this manner, each portion of the valve member can be constructed from a material that is best suited for its intended function. For example, in some embodiments, the sealing portions can be fabricated from a relatively soft stainless steel, such as for example, unhardened 430FR stainless steel, so that the sealing portions will readily wear when contacting the interior surface of the cylinder head. In this manner, the valve member can be continuously lapped during use, thereby ensuring a fluid-tight seal. In some embodiments, for example, the tapered portion can be fabricated from a relatively hard material having high strength, such as for example, hardened440stainless steel. Such a material can provide the necessary strength and/or hardness to resist failure that may result from repeated exposure to high temperature exhaust gas. In some embodiments, for example, one or both stem portions can be fabricated from a ceramic material configured to have high compressive strength.

In some embodiments, the cylinder head332, including the interior surface334that defines the valve pocket338, is monolithically constructed from a single material, such as, for example, cast iron. In some monolithic embodiments, for example, the interior surface334defining the valve pocket338can be machined to provide a suitable surface for engaging the sealing portions372of the valve member360such that a fluid-tight seal can be formed. In other embodiments, however, the cylinder head can be fabricated from any suitable combination of materials. As discussed in more detail herein, in some embodiments, a cylinder head can include one or more valve inserts disposed within the valve pocket. In this manner, the portion of the interior surface configured to contact the sealing portions of the valve member can be constructed from a material and/or in a manner conducive to providing a fluid-tight seal.

Although the flow passages368are shown and described as extending through the tapered portion362of the valve member360and having a first opening369and a second opening370, in other embodiments, the flow passages do not extend through the valve member.FIGS. 15 and 16show a top view and a front view, respectively, of a valve member560according to an embodiment in which the flow passages568extend around an outer surface563of the valve member560. Similar to the valve member360described above, the valve member560includes a first stem portion576, a second stem portion577and a tapered portion562. The tapered portion562defines four flow passages568and eight sealing portions572, each disposed adjacent to the edges of the flow passages568. Rather than extending through the tapered portion562, the illustrated flow passages568are recesses in the outer surface563that extend continuously around the outer surface563of the tapered portion562.

In other embodiments, the flow passages can be recesses that extend only partially around the outer surface of the tapered portion (seeFIGS. 24 and 25, discussed in more detail herein). In yet other embodiments, the tapered portion can include any suitable combination of flow passage configurations. For example, in some embodiments, some of the flow passages can be configured to extend through the tapered portion while other flow passages can be configured to extend around the outer surface of the tapered portion.

Although the valve members are shown and described above as including multiple sealing portions that extend around the perimeter of the tapered portion, in other embodiments, the sealing portion does not extend around the perimeter of the tapered portion. For example,FIG. 17shows a perspective view of a valve member660according to an embodiment in which the sealing portions672extend continuously around the openings669of the flow passages668. Similar to the valve members described above, the valve member660includes a first stem portion676, a second stem portion677and a tapered portion662. The tapered portion662defines four flow passages668extending therethrough. Each flow passage668includes a first opening669and a second opening (not shown) disposed opposite the first opening. As described above, the first opening and the second opening of each flow passage668are configured to align with corresponding gas manifold flow passages and cylinder flow passages, respectively, defined by the cylinder head (not shown).

The tapered portion662includes four sealing portions672disposed on the outer surface663of the tapered portion662. Each sealing portion672includes a locus of points that extends continuously around a first opening669. In this arrangement, when the cylinder head assembly is in the closed configuration, the sealing portion672contacts a portion of the interior surface (not shown) of the cylinder head (not shown) such that the first opening669is fluidically isolated from its corresponding gas manifold flow passage (not shown). Although shown as including four sealing portions672, each extending continuously around a first opening669, in some embodiments, the sealing portions can extend continuously around the second opening670, thereby fluidically isolating the second opening from the corresponding cylinder flow passage when the cylinder head assembly is in the closed configuration. In other embodiments, a valve member can include sealing portions extending around both the first opening669and the second opening670.

FIG. 18shows a perspective view of a valve member760according to an embodiment in which the sealing portions772are two-dimensional. As illustrated, the valve member760includes a tapered portion772, a first stem portion776and a second stem portion777. As described above, the tapered portion includes four flow passages768therethrough. The tapered portion also includes four sealing portions772each disposed adjacent each flow passage768and extending continuously around a first opening769of the flow passages768. The sealing portions772differ from the sealing portions672described above, in that the sealing portions772have a width X as measured along the longitudinal axis Lv of the valve member760.

FIG. 19shows a perspective view of a valve member860according to an embodiment in which the sealing portions872extend around the perimeter of the tapered portion862and extend around the first openings869. Similar to the valve members described above, the valve member860includes a first stem portion876, a second stem portion877and a tapered portion862. The tapered portion862defines four flow passages868extending therethrough. Each flow passage868includes a first opening869and a second opening (not shown) disposed opposite the first opening. The tapered portion862includes sealing portions872disposed on the outer surface863of the tapered portion862. As shown, each sealing portion872extends around the perimeter of the tapered portion862and extends around the first openings869. In some embodiments, the sealing portions can comprise the entire space between adjacent openings.

As discussed above, in some embodiments, a cylinder head can include one or more valve inserts disposed within the valve pocket. For example,FIGS. 20 and 21show a portion of a cylinder head assembly930having a valve insert942disposed within the valve pocket938. The illustrated cylinder head assembly930includes a cylinder head932and a valve member960. The cylinder head932has a first exterior surface935configured to be coupled to a cylinder (not shown) and a second exterior surface936configured to be coupled to a gas manifold (not shown). The cylinder head932has an interior surface934that defines a valve pocket938having a longitudinal axis Lp. The cylinder head932also defines four cylinder flow passages948and four gas manifold flow passages944, configured in a manner similar to those described above.

The valve insert942includes a sealing portion940and defines four insert flow passages945that extend through the valve insert. The valve insert942is disposed within the valve pocket938such that a first portion of each insert flow passage945is aligned with one of the gas manifold flow passages944and a second portion of each insert flow passage945is aligned with one of the cylinder flow passages948.

The valve member960has a tapered portion962, a first stem portion976and a second stem portion977. The tapered portion962has an outer surface963and defines four flow passages968extending therethrough, as described above. The tapered portion962also includes multiple sealing portions (not shown) each of which is disposed adjacent one of the flow passages968. The sealing portions can be of any type discussed above. The valve member960is disposed within the valve pocket938such that the tapered portion962of the valve member960can be moved along a longitudinal axis Lv of the valve member960within the valve pocket938between an opened position (FIGS. 20 and 21) and a closed position (not shown). When in the opened position, the valve member960is positioned within the valve pocket938such that each flow passage968is aligned with and in fluid communication with one of the insert flow passages945, one of the cylinder flow passages948and one of the gas manifold flow passages944. Conversely, when in the closed position, the valve member960is positioned within the valve pocket938such that the sealing portions are in contact with the sealing portion940of the valve insert942. In this manner, the flow passages968are fluidically isolated from the cylinder flow passages948and/or the gas manifold flow passages944.

As shown inFIG. 21, the valve pocket938, the valve insert942and the valve member960all have a circular cross-sectional shape. In other embodiments, the valve pocket can have a non-circular cross-sectional shape. For example, in some embodiments, the valve pocket can include an alignment surface configured to mate with a corresponding alignment surface on the valve insert. Such an arrangement may be used, for example, to ensure that the valve insert is properly aligned (i.e., that the insert flow passages945are rotationally aligned to be in fluid communication with the gas manifold flow passages944and the cylinder flow passages948) when the valve insert942is installed into the valve pocket938. In other embodiments, the valve pocket, the valve insert and/or the valve member can have any suitable cross-sectional shape.

The valve insert942can be coupled within the valve pocket938using any suitable method. For example, in some embodiments, the valve insert can have an interference fit with the valve pocket. In other embodiments, the valve insert can be secured within the valve pocket by a weld, by a threaded coupling arrangement, by peening a surface of the valve pocket to secure the valve insert, or the like.

FIG. 22shows a cross-sectional view of a portion of a cylinder head assembly1030according to an embodiment that includes multiple valve inserts1042. AlthoughFIG. 22only shows one half of the cylinder head assembly1030, one skilled in the art should recognize that the cylinder head assembly is generally symmetrical about the longitudinal axis Lp of the valve pocket, and is similar to the cylinder head assemblies shown and described above. The illustrated cylinder head assembly1030includes a cylinder head1032and a valve member1060. As described above, the cylinder head1032can be coupled to at least one cylinder and at least one gas manifold. The cylinder head1032has an interior surface1034that defines a valve pocket1038having a longitudinal axis Lp. The cylinder head1032also defines three cylinder flow passages (not shown) and three gas manifold flow passages1044.

As shown, the valve pocket1038includes several discontinuous, stepped portions. Each stepped portion includes a surface substantially parallel to the longitudinal axis Lp, through which one of the gas manifold passages1044extends. A valve insert1042is disposed within each discontinuous, stepped portion of the valve pocket1038such that a sealing portion1040of the valve insert1042is adjacent the tapered portions1061of the valve member1060. In this arrangement, the valve inserts1042are not disposed about the gas manifold flow passages1044and therefore do not have an insert flow passage of the type described above.

The valve member1060has a central portion1062, a first stem portion1076and a second stem portion1077. The central portion1062includes three tapered portions1061, each disposed adjacent a surface that is substantially parallel to the longitudinal axis of the valve member Lv. The central portion1062defines three flow passages1068extending therethrough and having an opening disposed on one of the tapered portions1061. Each tapered portion1061includes one or more sealing portions of any type discussed above. The valve member1060is disposed within the valve pocket1038such that the central portion1062of the valve member1060can be moved along a longitudinal axis Lv of the valve member1060within the valve pocket1038between an opened position (shown inFIG. 22) and a closed position (not shown). When in the opened position, the valve member1060is positioned within the valve pocket1038such that each flow passage1068is aligned with and in fluid communication with one of the cylinder flow passages (not shown) and one of the gas manifold flow passages1044. Conversely, when in the closed position, the valve member1060is positioned within the valve pocket1038such that the sealing portions on the tapered portions1061are in contact with the sealing portion1040of the corresponding valve insert1042. In this manner, the flow passages1068are fluidically isolated from the gas manifold flow passages1044and/or the cylinder flow passages (not shown).

Although the cylinder heads are shown and described above as having the same number of gas manifold flow passages and cylinder flow passages, in some embodiments, a cylinder head can have fewer gas manifold flow passages than cylinder flow passages or vice versa. For example,FIG. 23shows a cylinder head assembly1160according to an embodiment that includes a four cylinder flow passages1148by only one gas manifold flow passage1144. The illustrated cylinder head assembly1130includes a cylinder head1132and a valve member1160. The cylinder head1132has a first exterior surface1135configured to be coupled to a cylinder (not shown) and a second exterior surface1136configured to be coupled to a gas manifold (not shown). The cylinder head1132has an interior surface1134that defines a valve pocket1138within which the valve member1160is disposed. As shown, the cylinder head1132defines four cylinder flow passages1148and one gas manifold flow passage1144, configured similar to those described above.

The valve member1160has a tapered portion1162, a first stem portion1176and a second stem portion1177. The tapered portion1162defines four flow passages1168extending therethrough, as described above. The tapered portion1162also includes multiple sealing portions each of which is disposed adjacent one of the flow passages1168. The sealing portions can be of any type discussed above.

The cylinder head assembly1130differs from those described above in that when the cylinder head assembly1130is in the closed configuration (seeFIG. 23), the flow passages1168are not fluidically isolated from the gas manifold flow passage1144. Rather, the flow passages1168are only isolated from the cylinder flow passages1148, in a manner described above.

Although the engines are shown and described as having a cylinder coupled to a first surface of a cylinder head and a gas manifold coupled to a second surface of a cylinder head, wherein the second surface is opposite the first surface thereby producing a “straight flow” configuration, the cylinder and the gas manifold can be arranged in any suitable configuration. For example, in some instances, it may be desirable for the gas manifold to be coupled to a side surface1236of a the cylinder head.FIGS. 24 and 25show a cylinder head assembly1230according to an embodiment in which the cylinder flow passages1248are substantially normal to the gas manifold flow passages1244. In this manner, a gas manifold (not shown) can be mounted on a side surface1236of the cylinder head1232.

The illustrated cylinder head assembly1230includes a cylinder head1232and a valve member1260. The cylinder head1232has a bottom surface1235configured to be coupled to a cylinder (not shown) and a side surface1236configured to be coupled to a gas manifold (not shown). The side surface1236is disposed adjacent to and substantially normal to the bottom surface1235. In other embodiments, the side surface can be angularly offset from the bottom surface by an angle other than 90 degrees. The cylinder head1232has an interior surface1234that defines a valve pocket1238having a longitudinal axis Lp. The cylinder head1232also defines four cylinder flow passages1248and four gas manifold flow passages1244. The cylinder flow passages1248and the gas manifold flow passages1244differ from those previously discussed in that the cylinder flow passages1248are substantially normal to the gas manifold flow passages1244.

The valve member1260has a tapered portion1262, a first stem portion1276and a second stem portion1277. The tapered portion1262includes an outer surface1263and defines four flow passages1268. The flow passages1268are not lumens that extend through the tapered portion1262, but rather are recesses in the tapered portion1262that extend partially around the outer surface1263of the tapered portion1262. The flow passages1268include a curved surface1271to direct the flow of gas through the valve member1260in a manner that minimizes the flow losses. In some embodiments, a surface1271of the flow passages1268can be configured to produce a desired flow characteristic, such as, for example, a rotational flow pattern in the incoming and/or outgoing flow.

The tapered portion1262also includes multiple sealing portions (not shown) each of which is disposed adjacent one of the flow passages1268. The sealing portions can be of any type discussed above. The valve member1260is disposed within the valve pocket1238such that the tapered portion1262of the valve member1260can be moved along a longitudinal axis Lv of the valve member1260within the valve pocket1238between an opened position (FIGS. 24 and 25) and a closed position (not shown), as described above.

Although the flow passages defined by the valve member have been shown and described as being substantially parallel to each other and substantially normal to the longitudinal axis of the valve member, in some embodiments the flow passages can be angularly offset from each other and/or can be offset from the longitudinal axis of the valve member by an angle other than 90 degrees. Such an offset may be desirable, for example, to produce a desired flow characteristic, such as, for example, swirl or tumble pattern in the incoming and/or outgoing flow.FIG. 26shows a cross-sectional view of a valve member1360according to an embodiment in which the flow passages1368are angularly offset from each other and are not normal to the longitudinal axis Lv. Similar to the valve members described above, the valve member1360includes a tapered portion1362that defines four flow passages1368extending therethrough. Each flow passage1368has a longitudinal axis Lf. As illustrated, the longitudinal axes Lf are angularly offset from each other. Moreover, the longitudinal axes Lf are offset from the longitudinal axis of the valve member by an angle other than 90 degrees.

Although the flow passages1368are shown and described as having a linear shape and defining a longitudinal axis Lf, in other embodiments, the flow passages can have a curved shape characterized by a curved centerline. As described above, flow passages can be configured to have a curved shape to produce a desired flow characteristic in the gas entering and/or exiting the cylinder.

FIG. 27is a perspective view of a valve member1460according to an embodiment that includes a one-dimensional tapered portion1462. The illustrated valve member1460includes a tapered portion1462that defines three flow passages1468extending therethrough. The tapered portion includes three sealing portions1472, each of which is disposed adjacent one of the flow passages1468and extends continuously around an opening of the flow passage1468.

The tapered portion1462of the valve member1460has a width W measured along a first axis Y that is normal to a longitudinal axis Lv of the tapered portion1462. Similarly, the tapered portion1462has a thickness T measured along a second axis Z that is normal to both the longitudinal axis Lv and the first axis Y. The tapered portion1462has a one-dimensional taper characterized by a linear change in the thickness T. Conversely, the width W remains constant along the longitudinal axis Lv. As shown, the thickness of the tapered portion1462increases from a value of T1at one end of the tapered portion1462to a value of T2at the opposite end of the tapered portion1462. The change in thickness along the longitudinal axis Lv defines a taper angle α.

Although the valve members have been shown and described as including at least one tapered portion that includes one or more sealing portions, in some embodiments, a valve member can include a sealing portion disposed on a non-tapered portion of the valve member. In other embodiments, a valve member can be devoid of a tapered portion.FIG. 28is a front view of a valve member1560that is devoid of a tapered portion. The illustrated valve member1560has a central portion1562, a first stem portion1576and a second stem portion1577. The central portion1562has an outer surface1563and defines three flow passages1568extending continuously around the outer surface1563of the central portion1562, as described above. The central portion1562also includes multiple sealing portions1572each of which is disposed adjacent one of the flow passages1568and extends continuously around the perimeter of the central portion1562.

In a similar manner as described above, the valve member1560is disposed within a valve pocket (not shown) such that the central portion1562of the valve member1560can be moved along a longitudinal axis Lv of the valve member1560within the valve pocket between an opened position and a closed position. When in the opened position, the valve member1560is positioned within the valve pocket such that each flow passage1568is aligned with and in fluid communication with the corresponding cylinder flow passages and gas manifold flow passages (not shown). Conversely, when in the closed position, the valve member1560is positioned within the valve pocket such that the sealing portions1572are in contact with a portion of the interior surface of the cylinder head, thereby are fluidically isolating the flow passages1568.

As described above, the sealing portions1572can be, for example, sealing rings that are disposed within a groove defined by the outer surface of the valve member. Such sealing rings can be, for example, spring-loaded rings, which are configured to expand radially, thereby ensuring contact with the interior surface of the cylinder head when the valve member1560is in the closed position.

Conversely,FIGS. 29 and 30show portion of a cylinder head assembly1630that includes multiple 90 degree tapered portions1631in a first and second configuration, respectively. AlthoughFIGS. 29 and 30only show one half of the cylinder head assembly1630, one skilled in the art should recognize that the cylinder head assembly is generally symmetrical about the longitudinal axis Lp of the valve pocket, and is similar to the cylinder head assemblies shown and described above. The illustrated cylinder head assembly1630includes a cylinder head1632and a valve member1660. The cylinder head1632has an interior surface1634that defines a valve pocket1638having a longitudinal axis Lp and several discontinuous, stepped portions. The cylinder head1632also defines three cylinder flow passages (not shown) and three gas manifold flow passages1644.

The valve member1660has a central portion1662, a first stem portion1676and a second stem portion1677. The central portion1662includes three tapered portions1661and three non-tapered portions1667. The tapered portions1661each have a taper angle of 90 degrees (i.e., substantially normal to the longitudinal axis Lv). Each tapered portion1661is disposed adjacent one of the non-tapered portions1667. The central portion1662defines three flow passages1668extending therethrough and having an opening disposed on one of the non-tapered portions1667. Each tapered portion1661includes a sealing portion that extends around the perimeter of the outer surface of the valve member1660.

The valve member1660is disposed within the valve pocket1638such that the central portion1662of the valve member1660can be moved along a longitudinal axis Lv of the valve member1660within the valve pocket1638between an opened position (shown inFIG. 29) and a closed position (shown inFIG. 30). When in the opened position, the valve member1660is positioned within the valve pocket1638such that each flow passage1668is aligned with and in fluid communication with one of the cylinder flow passages (not shown) and one of the gas manifold flow passages1644. Conversely, when in the closed position, the valve member1660is positioned within the valve pocket1638such that the sealing portions on the tapered portions1661are in contact with a corresponding sealing portion1640defined by the valve pocket1638. In this manner, the flow passages1668are fluidically isolated from the gas manifold flow passages1644and/or the cylinder flow passages (not shown).

Although some of the valve members are shown and described as including a first stem portion configured to engage a camshaft and a second stem portion configured to engage a spring, in some embodiments, a valve member can include a first stem portion configured to engage a biasing member and a second stem portion configured to engage an actuator. In other embodiments, an engine can include two camshafts, each configured to engage one of the stem portions of the valve member. In this manner, the valve member can be biased in the closed position by a valve lobe on the camshaft rather than a spring. In yet other embodiments, an engine can include one camshaft and one actuator, such as, for example, a pneumatic actuator, a hydraulic actuator, an electronic solenoid actuator or the like.

FIG. 31is a top view of a portion of an engine1700according to an embodiment that includes both camshafts1714and solenoid actuators1716configured to move the valve member1760. The engine1700includes a cylinder1703, a cylinder head assembly1730and a gas manifold (not shown). The cylinder head assembly1730includes a cylinder head1732, an intake valve member1760I and an exhaust valve member1760E. The cylinder head1732can include any combination of the features discussed above, such as, for example, an intake valve pocket, an exhaust valve pocket, multiple cylinder flow passages, at least one manifold flow passage and the like.

The intake valve member1760I has tapered portion1762I, a first stem portion1776I and a second stem portion1777I. The first stem portion1776I has a first end1778I and a second end1779I. Similarly, the second stem portion1777I has a first end1792I and a second end1793I. The first end1778I of the first stem portion1776I is coupled to the tapered portion1762I. The second end1779I of the first stem portion1776I includes a roller-type follower1790I configured to engage an intake valve lobe1715I of an intake camshaft1714I. The first end1792I of the second stem portion1777I is coupled to the tapered portion1762I. The second end1793I of the second stem portion1777I is coupled to an actuator linkage1796I, which is coupled a solenoid actuator1716I.

Similarly, the exhaust valve member1760E has tapered portion1762E, a first stem portion1776E and a second stem portion1777E. A first end1778E of the first stem portion1776E is coupled to the tapered portion1762E. A second end1779E of the first stem portion1776E includes a roller-type follower1790E configured to engage an exhaust valve lobe1715E of an exhaust camshaft1714E. A first end1792E of the second stem portion1777E is coupled to the tapered portion1762E. A second end1793E of the second stem portion1777E is coupled to an actuator linkage1796E, which is coupled a solenoid actuator1716E.

In this arrangement, the valve members1760I,1760E can be moved by the intake valve lobe1715I and the exhaust valve lobe1715E, respectively, as described above. Additionally, the solenoid actuators1716I,1716E can supply a biasing force to bias the valve members1760I,1760E in the closed position, as indicated by the arrows F (intake) and J (exhaust). Moreover, in some embodiments, the solenoid actuators1716I,1716E can be used to override the standard valve timing as prescribed by the valve lobes1715I,1715E, thereby allowing the valves1760I,1760E to remain open for a greater duration (as a function of crank angle and/or time).

Although the engine1700is shown and described as including a solenoid actuator1716and a camshaft1714for controlling the movement of the valve members1760, in other embodiments, an engine can include only a solenoid actuator for controlling the movement of each valve member. In such an arrangement, the absence of a camshaft allows the valve members to be opened and/or closed in any number of ways to improve engine performance. For example, as discussed in more detail herein, in some embodiments the intake and/or exhaust valve members can be cycled opened and closed multiple times during an engine cycle (i.e., 720 crank degrees for a four stroke engine). In other embodiments, the intake and/or exhaust valve members can be held in a closed position throughout an entire engine cycle.

The cylinder head assemblies shown and described above are particularly well suited for camless actuation and/or actuation at any point in the engine operating cycle. More specifically, as previously discussed, because the valve members shown and described above do not extend into the combustion chamber when in their opened position, they will not contact the piston at any time during engine operation. Accordingly, the intake and/or exhaust valve events (i.e., the point at which the valves open and/or close as a function of the angular position of the crankshaft) can be configured independently from the position of the piston (i.e., without considering valve-to-piston contact as a limiting factor). For example, in some embodiments, the intake valve member and/or the exhaust valve member can be fully opened when the piston is at top dead center (TDC).

Moreover, the valve members shown and described above can be actuated with relatively little power during engine operation, because the opening of the valve members is not opposed by cylinder pressure, the stroke of the valve members is relatively low and/or the valve springs opposing the opening of the valves can have relatively low biasing force. For example, as discussed above, the stroke of the valve members can be reduced by including multiple flow passages therein and reducing the spacing between the flow passages. In some embodiments, the stroke of a valve member can be 2.3 mm (0.090 in.).

In addition to directly reducing the power required to open the valve member, reducing the stroke of the valve member can also indirectly reduce the power requirements by allowing the use of valve springs having a relatively low spring force. In some embodiments, the spring force can be selected to ensure that a portion of the valve member remains in contact with the actuator during valve operation and/or to ensure that the valve member does not repeatedly oscillate along its longitudinal axis when opening and/or closing. Said another way, the magnitude of the spring force can be selected to prevent valve “bounce” during operation. In some embodiments, reducing the stroke of the valve member can allow for the valve member to be opened and/or closed with reduced velocity, acceleration and jerk (i.e., the first derivative of the acceleration) profiles, thereby minimizing the impact forces and/or the tendency for the valve member to bounce during operation. As a result, some embodiments, the valve springs can be configured to have a relatively low spring force. For example, in some embodiments, a valve spring can be configured to exert a spring force of 110 N (50 lbf) when the valve member is both in the closed position and the opened position.

As a result of the reduced power required to actuate the valve members1760I,1760E, in some embodiments, the solenoid actuators1716I,1716E can be 12 volt actuators requiring relatively low current. For example, in some embodiments, the solenoid actuators can operate on 12 volts with a current draw during valve opening of between 14 and 15 amperes of current. In other embodiments, the solenoid actuators can be 12 volt actuators configured to operate on a high voltage and/or current during the initial valve member opening event and a low voltage and/or current when holding the valve member open. For example, in some embodiments, the solenoid actuators can operate on a “peak and hold” cycle that provides an initial voltage of between 70 and 90 volts during the first 100 microseconds of the valve opening event.

In addition to reducing engine parasitic losses, the reduced power requirements and/or reduced valve member stroke also allow greater flexibility in shaping the valve events. For example, in some embodiments the valve members can be configured to open and/or close such that the flow area through the valve member as a function of the crankshaft position approximates a square wave.

As described above, in some embodiments, the intake valve member and/or the exhaust valve member can be held open for longer durations, opened and closed multiple times during an engine cycle and the like.FIG. 32is a schematic of a portion of an engine1800according to an embodiment. The engine1800includes an engine block1802defining two cylinders1803. The cylinders1803can be, for example, two cylinders of a four cylinder engine. A reciprocating piston1804is disposed within each cylinder1803, as described above. A cylinder head1830is coupled to the engine block1802. Similar to the cylinder head assemblies described above, the cylinder head1830includes two electronically actuated intake valves1860I and two electronically actuated exhaust valves1860E. The intake valves1860I are configured to control the flow of gas between an intake manifold1810I and each cylinder1803. Similarly, the exhaust valves1860E control the exchange of gas between an exhaust manifold1810E and each cylinder.

The engine1800includes an electronic control unit (ECU)1896in communication with each of the intake valves1860I and the exhaust valves1860E. The ECU is processor of the type known in the art configured to receive input from various sensors, determine the desired engine operating conditions and convey signals to various actuators to control the engine accordingly. In the illustrated embodiment, the ECU1896is configured determine the appropriate valve events and provide an electronic signal to each of the valves1860I,1860E so that the valves open and close as desired.

The ECU1896can be, for example, a commercially-available processing device configured to perform one or more specific tasks related to controlling the engine1800. For example, the ECU1896can include a microprocessor and a memory device. The microprocessor can be, for example, an application-specific integrated circuit (ASIC) or a combination of ASICs, which are designed to perform one or more specific functions. In yet other embodiments, the microprocessor can be an analog or digital circuit, or a combination of multiple circuits. The memory device can include, for example, a read only memory (ROM) component, a random access memory (RAM) component, electronically programmable read only memory (EPROM), erasable electronically programmable read only memory (EEPROM), and/or flash memory.

Although the engine1800is illustrated and described as including an ECU1896, in some embodiments, an engine1800can include software in the form of processor-readable code instructing a processor to perform the functions described herein. In other embodiments, an engine1800can include firmware that performs the functions described herein.

FIG. 33is a schematic of a portion of the engine1800operating in a “cylinder deactivation” mode. Cylinder deactivation is a method of improving the overall efficiency of an engine by temporarily deactivating the combustion event in one or more cylinders during periods in which the engine is operating at reduced loads (i.e. when the engine is producing a relatively low amount of torque and/or power), such as, for example, when a vehicle is operating at highway speeds. Operating at reduced loads is inherently inefficient due to, among other things, the high pumping losses associated with throttling the intake air. In such instances, the overall engine efficiency can be improved by deactivating the combustion event in one or more cylinders, which requires the remaining cylinders to operate at a higher load and therefore with less throttling of the intake air, thereby reducing the pumping losses.

When the engine1800is operating in the cylinder deactivation mode, cylinder1803A, which can be, for example cylinder #4 of a four cylinder engine, is the firing cylinder, operating on a standard four stroke combustion cycle. Conversely, cylinder1803B, which can be, for example, cylinder #3 of a four cylinder engine, is the deactivated cylinder. As shown inFIG. 33, the engine1800is configured such that the piston1804A within the firing cylinder1803A is moving downwardly from top dead center (TDC) towards bottom dead center (BDC) on the intake stroke, as indicated by arrow AA. During the intake stroke, the intake valve1860IA is opened thereby allowing air or an air/fuel mixture to flow from the intake manifold1810I into the cylinder1803A, as indicated by arrow N. The exhaust valve1860EA is closed, such that the cylinder1803A is fluidically isolated from the exhaust manifold1810E.

Conversely, the piston1804B within the deactivated cylinder1803B is moving upwardly from BDC towards TDC, as indicated by arrow BB. As illustrated, the intake valve1860IB is opened thereby allowing air to flow from the cylinder1803B into the intake manifold1810I, as indicated by arrow P. The exhaust valve1860EB is closed such that the cylinder1803B is fluidically isolated from the exhaust manifold1810E. In this manner, the engine1800is configured so that cylinder1803B operates to pump air contained therein into the intake manifold1810I and/or cylinder1803A. Said another way, cylinder1803B is configured to act as a supercharger. In this manner, the engine1800can operate in a “standard” mode, in which cylinders1803A and1803B operate as naturally aspirated cylinders to combust fuel and air, and a “pumping assist” mode, in which cylinder1803B is deactivated and the cylinder1803A operates as a boosted cylinder to combust fuel and air.

Although the engine1800is shown and described operating in a cylinder deactivation mode in which one cylinder supplies air to another cylinder, in some embodiments, an engine can operate in a cylinder deactivation mode in which both the exhaust valve and the intake valve of the non-firing cylinder remain closed throughout the entire engine cycle. In other embodiments, an engine can operate in a cylinder deactivation mode in which the intake valve and/or exhaust valve of the non-firing cylinder is held open throughout the entire engine cycle, thereby eliminating the parasitic losses associated with pumping air through the non-firing cylinder. In yet other embodiments, an engine can operate in a cylinder deactivation mode in which the non-firing cylinder is configured to absorb power from the vehicle, thereby acting as a vehicle brake. In such embodiments, for example, the exhaust valve of the non-firing cylinder can be configured to open early so that the compressed air contained therein is released without producing any expansion work.

FIGS. 34-36are graphical representations of the valve events of a cylinder of a multi-cylinder engine operating in a standard four stroke combustion mode, a first exhaust gas recirculation (EGR) mode and a second EGR mode respectively. The longitudinal axes indicate the position of the piston within the cylinder in terms of the rotational position of the crankshaft. For example, the position of 0 degrees occurs when the piston is at top dead center on the firing stroke of the engine, the position of 180 degrees occurs when the piston is at bottom dead center after firing, the position of 360 degrees occurs when the piston is at top dead center on the gas exchange stroke, and so on. The regions bounded by dashed lines represent periods during which an intake valve associated with the cylinder is opened. Similarly, the regions bounded by solid lines represent the periods during which an exhaust valve associated with the cylinder is opened.

As shown inFIG. 34, when the engine is operating in a four stroke combustion mode, the compression event1910occurs after the gaseous mixture is drawn into the cylinder. During the compression event1910, both the intake and exhaust valves are closed as the piston moves upwardly towards TDC, thereby allowing the gaseous mixture contained in the cylinder to be compressed by the motion of the piston. At a suitable point, such as, for example −10 degrees, the combustion event1915begins. At a suitable point as the piston moves downwardly, such as, for example, 120 degrees, the exhaust valve open event1920begins. In some embodiments, the exhaust valve open event1920continues until the piston has reached TDC and has begun moving downwardly. Moreover, as shown inFIG. 34, the intake valve open event1925can begin before the exhaust valve open event1920ends. In some embodiments, for example, the intake valve open event1925can begin at 340 degrees and the exhaust valve open event1920can end at 390 degrees, thereby resulting in an overlap duration of 50 degrees. At a suitable point, such as, for example, 600 degrees, the intake valve open event1925ends and a new cycle begins.

In some embodiments, a predetermined amount of exhaust gas is conveyed from the exhaust manifold to the intake manifold via an exhaust gas recirculation (EGR) valve. In some embodiments, the EGR valve is controlled to ensure that precise amounts of exhaust gas are conveyed to the intake manifold.

As shown inFIG. 35, when the engine is operating in the first EGR mode, the intake valve associated with the cylinder is configured to convey exhaust gas from the cylinder directly into the intake manifold (not shown inFIG. 35), thereby eliminating the need for a separate EGR valve. As shown, the compression event1910′ occurs after the gaseous mixture is drawn into the cylinder. During the compression event1910′, both the intake and exhaust valves are closed as the piston moves upwardly towards TDC, thereby allowing the gaseous mixture contained in the cylinder to be compressed by the motion of the piston. As described above, at a suitable point, the combustion event1915′ begins. Similarly, at a suitable point the exhaust valve open event1920′ begins. At a suitable point during the exhaust valve event1920′, such as, for example, at 190 degrees, the first intake valve open event1950occurs. Because the first intake valve open event1950can be configured to occur when the pressure of the exhaust gas within the cylinder is greater than the pressure in the intake manifold, a portion of the exhaust gas will flow from the cylinder into the intake manifold. In this manner, exhaust gas can be conveyed directly into the intake manifold via the intake valve. The amount of exhaust gas flow can be controlled, for example, by varying the duration of the first intake valve open event1950, adjusting the point at which the first intake valve open event1950occurs and/or varying the stroke of the intake valve during the first intake valve open event1950.

As shown inFIG. 35, the second intake valve open event1925′ can begin before the exhaust valve open event1920′ ends. As described above, at suitable points, the first intake valve open event1950ends, the second intake valve open event1925′ ends and a new cycle begins.

As shown inFIG. 36, when the engine is operating in the second EGR mode, the exhaust valve associated with the cylinder is configured to convey exhaust gas from the exhaust manifold (not shown) directly into the cylinder (not shown inFIG. 35), thereby eliminating the need for a separate EGR valve. As shown, the compression event1910″ occurs after the gaseous mixture is drawn into the cylinder. During the compression event1910″, both the intake and exhaust valves are closed as the piston moves upwardly towards TDC, thereby allowing the gaseous mixture contained in the cylinder to be compressed by the motion of the piston. As described above, at a suitable point, the combustion event1915″ begins. Similarly, at a suitable point the first exhaust valve open event1920″ begins.

As described above, the intake valve open event1925″ can begin before the first exhaust valve open event1920″ ends. At a suitable point during the intake valve open event1925″, such as, for example, at 500 degrees, the second exhaust valve open event1960occurs. Because the second exhaust valve open event1960can be configured to occur when the pressure of the exhaust gas within the exhaust manifold is greater than the pressure in the cylinder, a portion of the exhaust gas will flow from the exhaust manifold into the cylinder. In this manner, exhaust gas can be conveyed directly into the cylinder via the exhaust valve. The amount of exhaust gas flow into the cylinder can be controlled, for example, by varying the duration of the second exhaust valve open event1960, adjusting the point at which the second exhaust valve open event1960occurs and/or varying the stroke of the exhaust valve during the second exhaust valve open event1960. As described above, at suitable points, the second exhaust valve open event1970ends, the intake valve open event1925″ ends and a new cycle begins.

Although the valve events are represented as square waves, in other embodiments, the valve events can have any suitable shape. For example, in some embodiments the valve events can be configured to as sinusoidal waves. In this manner, the acceleration of the valve member can be controlled to minimize the likelihood of valve bounce during the opening and/or closing of the valve.

In addition to allowing improvements in engine performance, the arrangement of the valve members shown and described above also results in improvements in the assembly, repair, replacement and/or adjustment of the valve members. For example, as previously discussed with reference toFIG. 5and as shown inFIG. 37the end plate323is removably coupled to the cylinder head332via cap screws317, thereby allowing access to the spring318and the valve member360for assembly, repair, replacement and/or adjustment. Because the valve member360does not extend below the first surface335of the cylinder head (i.e., the valve member360does not protrude into the cylinder303), the valve member360can be installed and/or removed without removing the cylinder head assembly330from the cylinder303. Moreover, because the tapered portion362of the valve member360is disposed within the valve pocket338such that the width and/or thickness of the valve member360increases away from the camshaft314(e.g., in the direction indicated by arrow C inFIG. 5), the valve member360can be removed without removing the camshaft314and/or any of the linkages (i.e., tappets) that can be disposed between the camshaft314and the valve member360. Additionally, the valve member360can be removed without removing the gas manifold310. For example, in some embodiments, a user can remove the valve member360by moving the end plate323such that the valve pocket338is exposed, removing the spring318, removing the alignment key398from the keyway399and sliding the valve member360out of the valve pocket338. Similar procedures can be followed to replace the spring318, which may be desirable, for example, to adjust the biasing force applied to the first stem portion377of the valve member360.

Similarly, an end plate322(seeFIG. 5) is removably coupled to the cylinder head332to allow access to the camshaft314and the first stem portion376for assembly, repair and/or adjustment. For example, as discussed in more detail herein, in some embodiments, a valve member can include an adjustable tappet (not shown) configured to provide a predetermined clearance between the valve lobe of the camshaft and the first stem portion when the cylinder head is in the closed configuration. In such arrangements, a user can remove the end plate322to access the tappet for adjustment. In other embodiments, the camshaft is disposed within a separate cam box (not shown) that is removably coupled to the cylinder head.

FIG. 38is a flow chart illustrating a method2000for assembling an engine according to an embodiment. The illustrated method includes coupling a cylinder head to an engine block,2002. As described above, in some embodiments, the cylinder head can be coupled to the engine block using cylinder head bolts. In other embodiments, the cylinder head and the engine block can be constructed monolithically. In such embodiments, the cylinder head is coupled to the engine block during the casting process. At2004, a camshaft is then installed into the engine.

The method then includes moving a valve member, of the type shown and described above, into a valve pocket defined by the cylinder head,2006. As previously discussed, in some embodiments, the valve member can be installed such that a first stem portion of the valve member is adjacent to and engages a valve lobe of the camshaft. Once the valve member is disposed within the valve pocket, a biasing member is disposed adjacent a second stem portion of the valve member,2008, and a first end plate is coupled to the cylinder head, such that a portion of the biasing member engages the first end plate,2010. In this manner, the biasing member is retained in place in a partially compressed (i.e., preloaded) configuration. The amount of biasing member preload can be adjusted by adding and/or removing spacers between the first end plate and the biasing member.

Because the biasing member can be configured to have a relatively low preload force, in some embodiments, the first end plate can be coupled to the cylinder head without using a spring compressor. In other embodiments, the cap screws securing the first end plate to the cylinder head can have a predetermined length such that the first end plate can be coupled to the cylinder without using a spring compressor.

The illustrated method then includes adjusting a valve lash setting,2012. In some embodiments, the valve lash setting is adjusted by adjusting a tappet disposed between the first stem portion of the valve member and the camshaft. In other embodiments, a method does not include adjusting the valve lash setting. The method then includes coupling a second end plate to the cylinder head,2014, as described above.

FIG. 39is a flow chart illustrating a method2100for replacing a valve member in an engine without removing the cylinder head according to an embodiment. The illustrated method includes moving an end plate to expose a first opening of a valve pocket defined by a cylinder head,2102. In some embodiments, the end plate can be removed from the cylinder head. In other embodiments, the end plate can be loosened and pivoted such that the first opening is exposed. A biasing member, which is disposed between a second end portion of the valve member and the end plate, is removed,2104. In this manner, the second end portion of the valve member is exposed. The valve member is then moved from within the valve pocket through the first opening,2106. In some embodiments, the camshaft can be rotated to assist in moving the valve member through the first opening. A replacement valve member is disposed within the valve pocket,2108. The biasing member is then replaced,2110, and the end plate is coupled to the cylinder head2112, as described above.

FIGS. 40-43are schematic illustrations of top view of a portion of an engine3100having a variable travel valve actuator assembly3200, according to an embodiment. The engine3100includes an engine block (not shown inFIGS. 40-43), a cylinder head3132, a valve3160and an actuator assembly3200. The engine block defines a cylinder3103(shown in dashed lines) within which a piston (not shown inFIGS. 40-43) can be disposed. The cylinder head3132is coupled to the engine block such that a portion of the cylinder head3132covers the upper portion of the cylinder3103thereby forming a combustion chamber. The cylinder head3132defines a valve pocket3138and four cylinder flow passages (not shown inFIGS. 40-43). The cylinder flow passages are in fluid communication with the valve pocket3138and the cylinder3103. In this manner, as described herein, a gas (e.g., an exhaust gas or an intake gas) can flow between a region outside of the engine3100and the cylinder3103via the cylinder head3132.

The valve3160has a first end portion3176and a second end portion3177, and defines four flow openings3168(only one of the flow openings is labeled inFIGS. 40-43). The flow openings3168correspond to the cylinder flow passages of the cylinder head3132. Although the valve3160is shown as defining four flow openings3168, in other embodiments, the valve3160can define any number of flow openings (e.g., one, two, three, or more). In some embodiments, the valve3160can be a tapered valve similar to the valve360shown and described above.

The valve3160is movably disposed within the valve pocket3138of the cylinder head3132. More particularly, the valve3160can move within the valve pocket3138between a closed position (e.g.,FIGS. 40 and 42) and multiple different opened positions (e.g.,FIGS. 41 and 43). When the valve3160is in the closed position, each flow opening3168is offset (or out of alignment with) from the corresponding cylinder flow passages. Moreover, when the valve3160is in the closed position, at least a portion of the valve3160is in contact with a portion of the interior surface of the cylinder head3132that defines the valve pocket3138such that the cylinder flow passages are fluidically isolated from the cylinder3103. In some embodiments, the valve3160can include a sealing portion (not shown inFIGS. 40-43), such as for example, a tapered surface, configured to engage a surface of the cylinder head3132to fluidically isolate the cylinder3103from the region outside of the engine3100.

As shown inFIGS. 40 and 42, when the valve3160is in the closed position, the first end portion3176of the valve is offset from an end plate3123by a distance dc1. A spring3118is disposed between the first end portion3176of the valve3160and an end plate3123. The spring3118exerts a force on the valve3160in the direction shown by the arrow CC inFIG. 40to bias the valve3160in the closed position. When the valve3160is in the closed position, the valve3160can be prevented from moving further in the direction shown by the arrow CC by any suitable mechanism. Such mechanisms can include, for example, mating tapered surfaces of the valve3160and the valve pocket3138, a mechanical end-stop, a magnetic device or the like.

As described in more detail below, the actuator assembly3200is configured to selectively vary the distance through which the valve3160travels when moving between the closed position and an opened position. Similarly stated, the valve3160can be moved between the closed position (FIGS. 40 and 42) and any number of different opened positions.FIG. 41illustrates the valve3160in a fully opened position, or the opened position corresponding to a first configuration of the actuator assembly3200.FIG. 43illustrates the valve3160in a partially opened position, or the opened position corresponding to a second configuration of the actuator assembly3200. When the valve3160is in an opened position, each flow opening3168of the valve3160is at least partially aligned with the corresponding cylinder flow passages. Moreover, when the valve3160is in an opened position, a portion of the valve3160is spaced apart from the interior surface of the cylinder head3132that defines the valve pocket3138such that the cylinder flow passages are in fluid communication with the cylinder3103. Thus, when the valve3160is in an opened position, a gas (e.g., an exhaust gas or an intake gas) can flow between a region outside of the engine3100and the cylinder3103via the cylinder head3132.

As shown inFIG. 41when the valve is in the first opened position (i.e., the fully opened position), the first end portion3176of the valve is offset from the end plate3123by a distance dop1. Thus, the distance through which the valve3160travels when moved from the closed position to the first opened position is represented by equation (1).
Travel1=dc1−dop1(1)
As shown inFIG. 43when the valve is in the second opened position (i.e., the partially opened position), the first end portion3176of the valve is offset from the end plate3123by a distance dop2, which is greater than the distance dop1. Thus, the distance through which the valve3160travels when moved from the closed position to the second opened position is less than the distance through which the valve3160travels when moved from the closed position to the first opened position. The distance through which the valve3160travels when moved from the closed position to the second opened position is represented by equation (2).
Travel2=dc1−dop2(2)

The actuator assembly3200includes a valve actuator3210and a variable travel actuator3250. The valve actuator3210includes a housing3240, a solenoid coil3242, a push rod3212and an armature3222. A first end portion3243of the housing3240is movably coupled to the cylinder head3132. In this manner, as described in more detail below, the housing3242(and therefore the valve actuator3210) can move relative to the cylinder head3132. The solenoid coil3242is fixedly coupled within the first end portion3243of the housing3240. Similarly stated, the solenoid coil3242is disposed within the housing3240such that movement of the solenoid coil3242relative to the housing3240is prevented.

The push rod3212has a first end portion3213and a second end portion3214. The second end portion3214of the push rod3212is disposed within the housing3240and is coupled to the armature3222. More particularly, the second end portion3214of the push rod3212is coupled to the armature3222such that movement of the armature3222results in movement of the push rod3212. A portion of the push rod3212is movably disposed within the solenoid coil3242. In this manner, the armature3222and the push rod3212can move relative to the solenoid coil3242. In use, when the solenoid coil3242is energized with an electrical current, a magnetic field is produced that exerts a force upon the armature3222in a direction shown by the arrows DD and FF inFIGS. 41 and 43, respectively. The magnetic force causes the armature3222and the push rod3212to move relative to the solenoid coil3242(and the housing3240), as shown by the arrows DD and FF inFIGS. 41 and 43, respectively. The armature3222and the push rod3212move relative to the solenoid coil3242through a distance Sd (i.e., the solenoid stroke) until the armature3222contacts the solenoid coil3242. When the solenoid coil3242is de-energized, the armature3222can travel in a direction opposite the direction shown by the arrows DD and FF until the armature contacts a second end portion4244of the housing4240. In some embodiments, the valve actuator4210includes a biasing member configured to urge the armature3222into contact with the second end portion of the housing4240.

The first end portion3213of the push rod3212is disposed outside of the housing3240. More particularly, when the housing3240is coupled to the cylinder head3132, the first end portion3213of the push rod3212is disposed within the valve pocket3138adjacent the second end portion3177of the valve3160. More particularly, as shown inFIGS. 40 and 42, when the valve3160is in the closed position and the solenoid coil3242is not energized, the first end portion3213of the push rod3212is spaced apart from the second end portion3177of the valve3160. The distance between the first end portion3213of the push rod3212and the second end portion3177of the valve3160is referred to as the valve lash (identified as L1inFIG. 40and L2inFIG. 42). Providing clearance (i.e., valve lash) between the push rod3212and the valve3160can ensure that the valve3160will be operate properly (e.g., be fully seated when in the closed position) regardless of the thermal growth of the valve train components, manufacturing tolerances of the valve train components, and/or the like.

In use, when the solenoid coil3242is energized and the push rod3212moves as shown by the arrow DD, the first end portion3213of the push rod3212contacts the second end portion3177of the valve3160. When the force exerted by the push rod3212on the valve3160is greater than the biasing force exerted by the spring3118, the valve3160is moved from the closed position (e.g.,FIG. 40) to an opened position (e.g.,FIG. 41). As described above, because the valve actuator3210is electrically operated, the valve3160can be moved between the closed position and an opened position independently from the rotational position of a camshaft or a crankshaft of the engine3100.

The variable travel actuator3250is configured to move the housing3240(and therefore, the valve actuator3210) relative to the cylinder head3132. In this manner, as described below, the variable travel actuator3250can selectively vary the distance through which the valve3160travels when moving between the closed position and an opened position. More particularly, the valve travel is related to the solenoid stroke Sd and the valve lash as indicated by equation (3).
Travel=Sd−L(3)
Thus, the valve travel can be adjusted by changing the solenoid stroke Sd and/or the valve lash L.

As shown inFIG. 40, when the actuator assembly3200is in the first (or full opening) configuration, the housing3240is positioned relative to the cylinder head3132such that the valve lash setting has a value of L1. Accordingly, the travel of the valve3160when the actuator assembly3200is in the first configuration is represented by equation (4).
Travel1=Sd−L1=dc1−dop1(4)
As shown inFIG. 42, when the actuator assembly3200is in the second (or partial opening) configuration, the housing3240is positioned relative to the cylinder head3132such that the valve lash setting has a value of L2, which is greater than L1. Similarly stated, when the actuator assembly3200is in the second (or partial opening) configuration, the housing3240is moved relative to the cylinder head3132as shown by the arrow EE inFIG. 42, thereby increasing the valve lash setting to a value of L2. Accordingly, the travel of the valve3160when the actuator assembly3200is in the second configuration is represented by equation (5).
Travel2=Sd−L2=dc1−dop2(5)

The variable travel actuator3250can include any suitable mechanism for moving the valve actuator3210relative to the cylinder head3132as shown by the arrow EE inFIG. 42. For example, in some embodiments, the variable travel actuator3250can include an electronic actuator that moves the valve actuator3210linearly relative to the cylinder head3132. Similarly stated, in some embodiments, the variable travel actuator3250can include an electronic actuator that translates the valve actuator3210relative to the cylinder head3132. For example, in some embodiments, the variable travel actuator3250can include a rack and pinion arrangement to translate the valve actuator3210relative to the cylinder head3132. In other embodiments, the variable travel actuator3250can rotate the valve actuator3210relative to the cylinder head. For example, in some embodiments, the housing3240can include a threaded portion configured to mate with a corresponding threaded portion in the cylinder head3132such that rotation of the housing3240relative to the cylinder head3132results in movement as shown by the arrow EE inFIG. 42.

As described above, the variable travel actuator3250varies the valve travel by selectively varying the valve lash L while maintaining a constant solenoid stroke Sd. In this manner, the electro-mechanical characteristics of the valve actuator3210remain substantially constant when the actuator assembly3200is moved between the first configuration and the second configuration. Accordingly, the current to energize the solenoid coil3242need not change as a function of the configuration of the actuator assembly3200.

As shown inFIGS. 40-43, the spring3118is disposed adjacent the opposite end of the valve3160(i.e., the first end portion3176) from the actuator assembly3200. This arrangement allows the variable travel actuator3250of the actuator assembly3200to move the valve actuator3210relative to the cylinder head3132without changing the functional characteristics of the spring3118. More particularly, the variable travel actuator3250of the actuator assembly3200can move the valve actuator3210relative to the cylinder head3132without changing the length of the spring3118when the valve3160is in the closed position (i.e., the initial length of the spring3118). In the illustrated embodiment, the initial length of the spring3118corresponds to the distance dc1between the end plate3123and the first end portion3176of the valve3160. By maintaining a substantially constant initial length of the spring3118, the variable travel actuator3250of the actuator assembly3200can move the valve actuator3210relative to the cylinder head3132without changing the biasing force exerted by the spring3118on the valve3160. Accordingly, the valve3160can be actuated in a repeatable and/or precise manner regardless of the configuration of the actuator assembly3200.

In addition to decreasing the valve travel, selectively increasing the lash (e.g., from L1to L2) can result in a longer time for the valve3160to begin moving after the solenoid3242is energized. Accordingly, in some embodiments, the timing of the actuation can be adjusted and/or offset as a function of the valve lash. For example, in some embodiments, the engine3100can include an electronic control unit or ECU (not shown) configured to automatically adjust the actuation timing as a function of the change in valve lash (e.g., L1to L2) when the actuation assembly3200is moved between the first configuration and the second configuration. In some embodiments, for example, the ECU can be configured to receive an input corresponding to the valve lash setting of the valve when the actuation assembly is in the first configuration (e.g., the full opening configuration) and adjust the actuation timing as a function of the actual change in valve lash setting. In this manner, the ECU can control the actuation timing for a particular engine, rather than based on nominal values for a general engine design.

Although the actuator assembly3200is shown as having only one partial opening configuration (e.g.,FIGS. 42 and 43), the actuator assembly3200can be moved between the full opening configuration and any number of partial opening configurations. For example, the actuator assembly3200can be moved between a full opening configuration, a first partial opening configuration (in which the valve travel is approximately ¾ of the full opening valve travel), a second partial opening configuration (in which the valve travel is approximately ½ of the full opening valve travel) and a third partial opening configuration (in which the valve travel is approximately ¼ of the full opening valve travel). In another example, the actuator assembly3200can be moved between the full opening configuration and an infinite number of partial opening configurations. For example in some embodiments, the actuator assembly3200can adjust the distance between the closed position and the opened position to any value between approximately zero inches and 0.090 inches. By selectively varying the distance between the opened position and the closed position (e.g., the valve travel), the actuator assembly3200can accurately and/or precisely control the amount and/or flow rate of gas flow into and/or out of the cylinder3103. More particularly, the valve travel can be varied in conjunction with the timing and duration of the valve opening event to provide the desired gas flow characteristics as a function of the engine operating conditions (e.g., low idle, road cruising conditions or the like). In some embodiments, the control afforded by this arrangement allows the engine gas exchange process to be controlled using only the valve3160and the actuator assembly3200, thereby removing the need for a throttle valve upstream of the cylinder head3132.

Although the top view schematic illustrations shown inFIGS. 40-43show the valve3160moving between the closed position and an opened position in a direction substantially normal to a center line (not shown) of the cylinder3103, in other embodiments, the valve3160can move in any suitable direction relative to the cylinder3103and/or the cylinder head3132. For example, in some embodiments, the valve3160can move substantially parallel to a center line of the cylinder3103. In other embodiments, the valve3160can move in a direction non-parallel to and non-normal to a center line of the cylinder3103.

Although the variable travel actuator3250is shown and described above as varying the valve travel by selectively varying the valve lash L while maintaining a constant solenoid stroke Sd, in other embodiments, a variable travel actuator can vary the valve travel by selectively varying the solenoid stroke while maintaining a substantially constant valve lash setting. For example,FIGS. 44 and 45are schematic illustrations of top view of a portion of an engine4100having a variable travel valve actuator assembly4200, according to an embodiment. The engine4100includes an engine block (not shown inFIGS. 44 and 45), a cylinder head4132, a valve4160and an actuator assembly4200. The engine block defines a cylinder4103(shown in dashed lines) within which a piston (not shown inFIGS. 44 and 45) can be disposed. The cylinder head4132is coupled to the engine block such that a portion of the cylinder head4132covers the upper portion of the cylinder4103thereby forming a combustion chamber. The cylinder head4132defines a valve pocket4138and four cylinder flow passages (not shown inFIGS. 44 and 45). The cylinder flow passages are in fluid communication with the valve pocket4138and the cylinder4103. In this manner, as described above, a gas (e.g., an exhaust gas or an intake gas) can flow between a region outside of the engine4100and the cylinder4103via the cylinder head4132.

The valve4160has a first end portion4176and a second end portion4177, and defines four flow openings4168(only one of the flow openings is labeled inFIGS. 44 and 45). The flow openings4168correspond to the cylinder flow passages of the cylinder head4132. Although the valve4160is shown as defining four flow openings4168, in other embodiments, the valve4160can define any number of flow openings (e.g., one, two, three, or more). In some embodiments, the valve4160can be a tapered valve similar to the valve360shown and described above.

The valve4160is movably disposed within the valve pocket4138of the cylinder head4132. More particularly, the valve4160can move within the valve pocket4138between a closed position (as shown inFIGS. 44 and 45) and multiple different opened positions (not shown inFIGS. 44 and 45). When the valve4160is in the closed position, the cylinder flow passages are fluidically isolated from the cylinder4103, as described above. A spring4118is disposed between the first end portion4176of the valve4160and an end plate4123. The spring4118exerts a force on the valve4160to bias the valve4160in the closed position, as described above. Similar to the arrangement described above with reference to the engine3100, the valve4160can be moved between the closed position (FIGS. 44 and 45) and any number of different opened positions. When the valve4160is in an opened position, the cylinder flow passages are in fluid communication with the cylinder4103. Thus, when the valve4160is in an opened position, a gas (e.g., an exhaust gas or an intake gas) can flow between a region outside of the engine4100and the cylinder4103via the cylinder head4132.

The actuator assembly4200includes a valve actuator4210and a variable travel actuator4250. The valve actuator4210includes a housing4240, a solenoid coil4242, a push rod4212and an armature4222. A first end portion4243of the housing4240is fixedly coupled to the cylinder head4132. The solenoid coil4242is movably disposed within the first end portion4243of the housing4240. In this manner, as described in more detail below, the solenoid coil4242can be selectively moved to vary the solenoid stroke, and therefore the valve travel.

The push rod4212has a first end portion4213and a second end portion4214. The second end portion4214of the push rod4212is disposed within the housing4240and is coupled to the armature4222. More particularly, the second end portion4214of the push rod4212is coupled to the armature4222such that movement of the armature4222results in movement of the push rod4212. A portion of the push rod4212is movably disposed within the solenoid coil4242. In this manner, the armature4222and the push rod4212can move relative to the solenoid coil4242. In use, when the solenoid coil4242is energized the armature4222and the push rod4212are moved relative to the solenoid coil4242(and the housing4240) until the armature4222contacts the solenoid coil4242. Similarly stated, when the solenoid coil4242is energized the armature4222and the push rod4212move relative to the solenoid coil4242a distance (i.e., the solenoid stroke). When the solenoid coil4242is de-energized, the armature4222can move in an opposite direction until the armature contacts a second end portion4244of the housing4240. In some embodiments, the valve actuator4210includes a biasing member configured to urge the armature4222into contact with the second end portion of the housing4240.

The first end portion4213of the push rod4212is disposed outside of the housing4240. More particularly, when the housing4240is coupled to the cylinder head4132, the first end portion4213of the push rod4212is disposed within the valve pocket4138adjacent the second end portion4177of the valve4160. As shown inFIGS. 44 and 45, when the valve4160is in the closed position and the solenoid coil4242is not energized, the first end portion4213of the push rod4212is spaced apart from the second end portion4177of the valve4160by a distance L (the valve lash). In use, when the solenoid coil4242is energized and the push rod4212moves, the first end portion4213of the push rod4212contacts the second end portion4177of the valve4160. When the force exerted by the push rod4212on the valve4160is greater than the biasing force exerted by the spring4118, the valve4160is moved from the closed position (e.g.,FIGS. 44 and 45) to an opened position (not shown).

The variable travel actuator4250is configured to move the solenoid coil4242within the housing4240relative to the armature4222and/or the push rod4212, as shown by the arrow HH inFIG. 45. In this manner, the actuator assembly4200can be moved between a first (or full opening) configuration, as shown inFIG. 44, and a second (or partial opening) configuration, as shown inFIG. 45. Although shown as having only one partial opening configuration, the actuator assembly4200can have any number of different partial opening configurations, as described above. As shown inFIG. 44, when the actuator assembly4200is in the first configuration, the armature4222is spaced apart from the solenoid4242when the solenoid is de-energized by a distance Sd1(i.e., the solenoid stroke when the actuator assembly4200is in the first configuration). As shown inFIG. 45, when the actuator assembly4200is in the second configuration, the armature4222is spaced apart from the solenoid4242when the solenoid is de-energized by a distance Sd2(i.e., the solenoid stroke when the actuator assembly4200is in the second configuration), which is less than the distance Sd1.

As described above, the valve travel is related to the solenoid stroke and the valve lash. Accordingly, the actuator assembly4200can selectively vary the valve travel by adjusting the solenoid stroke. Moreover, because the housing4240is fixedly coupled to the cylinder head4132, the position of the push rod4212relative to the valve4160when the solenoid4242is de-energized remains substantially constant when the actuator assembly4200is moved from the first configuration to the second configuration. Similarly stated, the valve lash L remains substantially constant when the actuator assembly4200is moved from the first configuration to the second configuration.

As shown inFIGS. 44 and 45, the variable travel actuator4250is coupled to the solenoid coil4242via a connector4251. In this manner, movement and/or force produced by the variable travel actuator4250can result in movement of the solenoid4242within the housing4240. More particularly, when the variable travel actuator4250rotates as shown by the arrow GG inFIG. 45, the solenoid coil4242moves within the housing4240as shown by the arrow HH inFIG. 45. The connector4251can be any suitable connector, such as, for example, a rod, a cable, a belt or the like. Moreover, the variable travel actuator4250can include any suitable mechanism for moving the solenoid coil4242within the housing4240, such as, for example, a stepper motor, an electronic actuator, a hydraulic actuator, a pneumatic actuator and/or the like.

FIGS. 46 and 47are perspective views of an engine5100having a variable travel intake valve actuator assembly5200and a variable travel exhaust valve actuator assembly5300, according to an embodiment. The engine5100includes an engine block5102, a cylinder head assembly5130, an intake valve actuator assembly5200and an exhaust valve actuator assembly5300. The engine block5102defines a cylinder5103(shown in dashed lines inFIGS. 51,52,59and60) within which a piston (not shown) can be disposed. The cylinder head assembly5130is coupled to the engine block5102such that a portion of the cylinder head assembly5130covers the upper portion of the cylinder5103to form a combustion chamber. A gas manifold5110is coupled to an upper surface of the cylinder head assembly5130. The gas manifold5110defines an exhaust gas pathway5112and an intake air pathway5111. In use, exhaust gas can be conveyed from the cylinder5103and into the exhaust gas pathway5112via the cylinder head assembly5130. Similarly, intake air (and/or any suitable intake charge) can be conveyed from the intake air pathway5111into the cylinder5103via the cylinder head assembly5130.

The cylinder head assembly5130includes a cylinder head5132, an intake valve5160I and an exhaust valve5160E. Referring toFIGS. 51-53, the cylinder head5132defines an intake valve pocket5138I within which the intake valve5160I is movably disposed. The cylinder head5132defines a set of cylinder flow passages5148I and a set of intake manifold flow passages5144I. Each of the cylinder flow passages5148I is in fluid communication with the cylinder5103(shown in dashed lines) and the intake valve pocket5138I. Similarly, each of the intake manifold flow passages5144I is in fluid communication with the intake air pathway5111of the gas manifold5110and the intake valve pocket5138I of the cylinder head5132. As described in more detail herein, in this arrangement, when the intake valve5160I is in the closed position (e.g.,FIG. 51), the intake pathway5111of the gas manifold5110is fluidically isolated from the cylinder5103. Conversely, when the intake valve5160I is in an opened position (e.g.,FIGS. 52 and 53), the intake pathway5111of the gas manifold5110is in fluid communication with the cylinder5103. Accordingly, the timing and/or amount of intake air conveyed into the cylinder5103can be controlled by varying the opening and closing events of the intake valve5160I. Although the intake valve5160I is shown as having two opened positions (FIGS. 52 and 53), as described in more detail below, the intake valve actuator assembly5200can selectively vary the distance through which the intake valve5160I travels when moved between the closed position and the opened position. In this manner, the intake valve5160I can be moved between the closed position and any number of different partially opened positions.

Referring toFIGS. 59-61, the cylinder head5132defines an exhaust valve pocket5138E within which the exhaust valve5160E is movably disposed. The cylinder head5132defines a set of cylinder flow passages5148E and a set of exhaust manifold flow passages5144E. Each of the cylinder flow passages5148E is in fluid communication with the cylinder5103(shown in dashed lines) and the exhaust valve pocket5138E. Similarly, each of the exhaust manifold flow passages5144E is in fluid communication with the exhaust pathway5112of the gas manifold5110and the exhaust valve pocket5138E of the cylinder head5132. As described in more detail herein, in this arrangement, when the exhaust valve5160E is in the closed position (e.g.,FIG. 59), the exhaust pathway5112of the gas manifold5110is fluidically isolated from the cylinder5103. Conversely, when the exhaust valve5160E is in an opened position (e.g.,FIGS. 60-61), the exhaust pathway5112of the gas manifold5110is in fluid communication with the cylinder5103. Accordingly, timing and/or amount of exhaust gas conveyed out of the cylinder5103can be controlled by varying the opening and closing events of the exhaust valve5160E. Although the exhaust valve5160E is shown as having only two opened positions (FIGS. 60 and 61), as described in more detail below, the exhaust valve actuator assembly5300can selectively vary the distance through which the exhaust valve5160E travels when moved between the closed position and the opened position. In this manner, the exhaust valve5160E can be moved between the closed position and any number of different partially opened positions.

Referring toFIGS. 54-56, the intake valve5160I has tapered portion5162I, a first end portion5176I and a second end portion5177I, and defines a center line CLI. As shown inFIG. 55, the second end portion5177I defines a threaded opening5178I within which the intake pull rod5212is threadedly coupled. The second end portion5177I includes a spring engagement surface5179against which the intake valve spring5118I is disposed (see e.g.,FIGS. 51-53). In this manner, the intake valve5160I can be biased in the closed position within the intake valve pocket5138I.

The tapered portion5162I of the intake valve5160I includes a first surface5164I and a second surface5165I. As shown inFIG. 56, the first surface5164I and the second surface5165I are each curved surfaces having a radius of curvature RIabout an axis parallel to the center line CLI. Although the first surface5164I and the second surface5165I are shown has having the same radius of curvature, in other embodiments, the radius of curvature of the first surface5164I can be different from the radius of curvature of the second surface5165I. Similarly stated in some embodiments, the tapered portion5162I of the intake valve5160I can be asymmetrical when viewed in a plane substantially normal to the center line CLI. The radius of curvature RIcan have any suitable value. In some embodiments, the radius of curvature RIcan be approximately 114 mm (4.5 inches).

As shown inFIG. 54, which illustrates a top view of the intake valve5160I, the tapered portion5162I of the intake valve5160I has a first taper angle Θ1. Similarly stated, a width of the tapered portion5162I as measured along a first axis normal to the center line CLIlinearly decreases along the center line CLI. As shown inFIG. 55, which presents a side view of the intake valve5160I, the first surface5164I and the second surface5165I are angularly offset from each other by a second taper angle αI. Similarly stated, a thickness of the tapered portion5162I as measured along a second axis normal to the center line CLIlinearly decreases along the center line CLI. In this manner, the tapered portion5162I of the intake valve5160I is tapered in two dimensions. The first taper angle ΘIand the second taper angle αIcan have any suitable value. For example, in some embodiments, the first taper angle ΘIhas a value of between approximately 3 degrees and approximately 10 degrees and the second taper angle αIhas a value of approximately 10 degrees (5 degrees for each side).

The tapered portion5162I of the intake valve5160I defines a set of flow passages5168I therethrough (only one flow passage is labeled inFIGS. 54 and 55). As shown inFIG. 55, the flow passages5168I are angularly offset from the center line CLIof the intake valve5160I by an angle βIgreater than ninety degrees. Similarly stated, a longitudinal axis AFPof each flow passage5168I is non-normal to the center line CLI. In this manner, as shown inFIGS. 51-53, when the intake valve5160I is disposed within the intake valve pocket5138I such that the center line CLIof the intake valve5160I is non-normal to a center line CLcylof the cylinder, the longitudinal axis AFPof each flow passage5168I is substantially normal to the center line CLcylthe cylinder.

As shown inFIG. 54, each flow passage5168I does not have the same shape and/or size as the other flow passages5168I. Rather, the size of the flow passages5168I closer to the ends of the tapered portion5162I is smaller than the size of the flow passages5168I at the center of the tapered portion5162I. In this manner, the size (e.g., length) of the flow passages5168I can correspond to the size and/or shape of the cylinder5103.

The first surface5164I of the tapered portion5162I and the second surface5165I of the tapered portion5162I each include a set of sealing portions (not shown inFIGS. 54-56) that correspond to the flow passages5168I. As described above, the sealing portions substantially circumscribe the openings of the first surface5164I and the second surface5165I. Thus, when the intake valve5160I is in the closed position, the sealing portions engage and/or contact the surface of the cylinder head5132that defines the intake valve pocket5138I such that the cylinder flow passages5148I and the intake manifold flow passages5144I are fluidically isolated from the intake valve pocket5138I.

Referring toFIGS. 62-64, the exhaust valve5160E has tapered portion5162E, a first end portion5176E and a second end portion5177E, and defines a center line CLE. As shown inFIG. 63, the second end portion5177E defines a threaded opening5178E within which the exhaust pull rod5312is threadedly coupled. The tapered portion5162E of the exhaust valve5160E includes a first surface5164E and a second surface5165E. As shown inFIG. 64, the first surface5164E and the second surface5165E are each curved surfaces having a radius of curvature REabout an axis parallel to the center line CLI. Although the first surface5164E and the second surface5165E are shown has having the same radius of curvature, in other embodiments, the radius of curvature of the first surface5164E can be different from the radius of curvature of the second surface5165E. Similarly stated in some embodiments, the tapered portion5162E of the exhaust valve5160E can be asymmetrical when viewed in a plane substantially normal to the center line CLI. The radius of curvature REcan have any suitable value. In some embodiments, the radius of curvature REcan be approximately can be approximately 47 mm (1.85 inches).

As shown inFIG. 62, which illustrates a top view of the exhaust valve5160E, the tapered portion5162E of the exhaust valve5160E has a first taper angle ΘE. Similarly stated, a width of the tapered portion5162E as measured along a first axis normal to the center line CLElinearly decreases along the center line CLE. As shown inFIG. 63, which presents a side view of the exhaust valve5160E, the first surface5164E and the second surface5165E are angularly offset from each other by a second taper angle αE. Similarly stated, a thickness of the tapered portion5162E as measured along a second axis normal to the center line CLElinearly decreases along the center line CLE. In this manner, the tapered portion5162E of the exhaust valve5160E is tapered in two dimensions. The first taper angle ΘEand the second taper angle αEcan have any suitable value. For example, in some embodiments, the first taper angle ΘEhas a value of between approximately 3 degrees and approximately 10 degrees and the second taper angle αEhas a value of approximately 10 degrees (5 degrees for each side).

The tapered portion5162E of the exhaust valve5160E defines a set of flow passages5168E therethrough (only one flow passage is labeled inFIGS. 62 and 63). As shown inFIG. 63, the flow passages5168E are angularly offset from the center line CLEof the exhaust valve5160E by an angle βEgreater than ninety degrees. Similarly stated, a longitudinal axis AFPof each flow passage5168E is non-normal to the center line CLE. In this manner, as shown inFIGS. 59-61, when the exhaust valve5160E is disposed within the exhaust valve pocket5138E such that the center line CLEof the exhaust valve5160E is non-normal to a center line CLcylof the cylinder, the longitudinal axis AFPof each flow passage5168E is substantially normal to the center line CLcylthe cylinder.

As shown inFIG. 62, each flow passage5168E does not have the same shape and/or size as the other flow passages5168E. Rather, the size of the flow passages5168E closer to the ends of the tapered portion5162E is smaller than the size of the flow passages5168E at the center of the tapered portion5162E. In this manner, the size (e.g., length) of the flow passages5168E can correspond to the size and/or shape of the cylinder5103.

The first surface5164E of the tapered portion5162E and the second surface5165E of the tapered portion5162E each include a set of sealing portions (not shown inFIGS. 62-64) that correspond to the flow passages5168E. As described above, the sealing portions substantially circumscribe the openings of the first surface5164E and the second surface5165E. Thus, when the exhaust valve5160E is in the closed position, the sealing portions engage and/or contact a surface of the cylinder head5132that defines the exhaust valve pocket5138E such that the cylinder flow passages5148E and the exhaust manifold flow passages5144E are fluidically isolated from the exhaust valve pocket5138E.

Referring to FIGS.49and51-53, the intake valve5160I is movably disposed within the intake valve pocket5138I of the cylinder head5132. A plug5182is disposed within the intake valve pocket5138I adjacent the second end portion5177I of the intake valve5160I. The plug5182has a tapered outer surface that corresponds to the shape of the intake valve pocket5138I. In this manner, the outer surface of the plug5182and the surface defining the intake valve pocket5138I can form a substantially fluid-tight seal. Moreover, the tapered outer surface of the plug5182prevents further inward movement of the plug5182when the plug5182is disposed within the intake valve pocket5138I. A spacer5184is disposed at least partially within the intake valve pocket5138I in contact with the plug5182. The spacer5184provides a mechanism by which the plug5182can be securely coupled within the intake valve pocket5138I. The spacer5184can be coupled within the valve pocket5138I by a set screw, a clamping force exerted by the housing5270or the like.

As shown inFIG. 52, when the intake valve5160I is in the fully opened position, the spring engagement surface5179of the intake valve5160I is spaced apart from the end of the plug5182. Thus, the plug5182does not provide a positive stop to limit the travel of the intake valve5160I within the valve pocket5138I. Rather, as described more detail below, the travel of the intake valve5160I is controlled by the intake valve actuator assembly5200. Moreover, as shown inFIGS. 51-53, the sleeve5182defines a spring groove5183within which an end portion of the intake valve spring5118I is disposed. The opposite end portion of the intake valve spring5118I is in contact with the spring engagement surface5179of the intake valve5160I. In this manner, the intake valve5160I is biased in the closed position within the intake valve pocket5138I.

Referring toFIGS. 49,59-61, the exhaust valve5160E is movably disposed within the exhaust valve pocket5138E of the cylinder head5132. A plug5180is disposed within the exhaust valve pocket5138E adjacent the second end portion5177E of the exhaust valve5160I. The plug5180has a tapered outer surface that corresponds to the shape of the exhaust valve pocket5138I. In this manner, the outer surface of the plug5180and the surface defining the exhaust valve pocket5138E can form a substantially fluid-tight seal. Moreover, when the plug5180is disposed within the exhaust valve pocket5138I, the tapered arrangement prevents further inward movement of the plug5182. A spacer5181is disposed at least partially within the exhaust valve pocket5138E in contact with the plug5180. The spacer5181provides a mechanism by which the plug5180can be securely coupled within the exhaust valve pocket5138I, as described above.

As shown inFIG. 60, when the exhaust valve5160E is in the fully opened position, the shoulder of the exhaust valve5160E is spaced apart from the end of the plug5182. In this manner, the plug5182does not provide a positive stop to limit the travel of the exhaust valve5160E within the valve pocket5138I. Rather, as described more detail below, the travel of the exhaust valve5160E is controlled by the exhaust valve actuator assembly5300. In contrast to the intake valve train, as shown inFIGS. 59-61, the exhaust valve spring5118E is disposed outside of the exhaust valve pocket5138E. In this manner, the exhaust valve spring5118E is not exposed to the high temperatures associated with the exhaust gas. As discussed in more detail herein, the exhaust valve spring5118E is disposed within the exhaust valve actuator assembly5300.

As described in more detail below, the intake actuator assembly5200is configured to move the intake valve5160I between its closed position and its opened position and selectively vary the distance through which the intake valve5160I travels when moving between its closed position and an opened position. Similarly stated, the intake actuator assembly5200is configured to move the intake valve5160I between its closed position (FIG. 51) and any number of different opened positions. Referring toFIG. 50, the intake actuator assembly5200includes a housing5270that contains a valve actuator5210and a variable travel actuator5250. More particularly, the housing5270defines a first cavity5272, within which the valve actuator5210is disposed, and a second cavity5275, within which a portion of the variable travel actuator5250is disposed. As shown inFIGS. 46 and 47, the housing5270is coupled to the cylinder head5132such that at least a portion of the first cavity5272is aligned with the intake valve pocket5138I. In this manner, as described in more detail below, the valve actuator5210can engage and/or actuate the intake valve5160I. Note thatFIGS. 51-53shows the housing5270as being spaced apart from the cylinder head5132for purposes of clarity.

The valve actuator5210is a electronic actuator configured to move the intake valve5160I between its closed position and its opened position. The valve actuator5210includes a solenoid assembly5230, a pull rod5212and an armature5222. The solenoid assembly5230includes a solenoid casing5240, a solenoid coil5242and an end stop5231. The solenoid casing5240has a threaded portion5246corresponding to a threaded portion5273side wall of the housing5270that defines the first cavity5272. Similarly stated, the outer surface of the solenoid casing5240includes male threads configured to mate with the female threads5273within the first cavity5272of the housing5270. In this manner, the solenoid assembly5230can be threadedly coupled within the first cavity5272of the housing5270. Thus, rotation of the solenoid assembly5230relative to the housing5270results in axial movement of the solenoid assembly5230within the first cavity5272, as shown by the arrow II inFIG. 53. In this manner, as described in more detail below, the solenoid stroke (i.e., the distance between the solenoid assembly5230and the armature5222when the solenoid is not energized) can be selectively adjusted.

The solenoid coil5242is disposed within the solenoid casing5240such that the lead wire5241of the solenoid coil5242are accessible from a region outside of the solenoid casing5240. Moreover, the solenoid coil5242is fixedly disposed within the solenoid casing5240. Similarly stated, the solenoid coil5242is disposed within the housing5240such that movement of the solenoid coil5242relative to the housing5240is prevented.

The end stop5231has a flanged portion5237and an end surface5235. The flanged portion5237is coupled to the solenoid casing5240such that the solenoid coil5242is enclosed and/or contained within the solenoid casing5240. The flanged portion5237can be coupled to the solenoid casing5240in any suitable manner, such as, for example, using cap screws, a snap ring, a welded joint, an adhesive and/or the like. When the end stop5231is coupled to the solenoid casing5240, the end surface5235is disposed within the central opening of the solenoid coil5242(see e.g.,FIGS. 51-53). The end surface5235of the end stop5231defines a groove5236within which an end portion of the armature spring5232is disposed. As described in more detail below, the end surface5235contacts the armature5222when the solenoid assembly5230is energized.

Referring toFIG. 57, the armature5222defines a lumen5225therethrough, and includes a flange5221and a contact surface5228. The lumen5225is counter-bored such that an inner surface of the armature5222has a shoulder5226. As described in more detail below, the shoulder5226is configured to engage the head5218of the pull rod5212to limit the axial movement of the armature5222relative to the pull rod5212. The flange5221has a diameter smaller than a diameter of the inner surface5274of the first cavity5272of the housing5270(see e.g.,FIG. 50). In this manner, the armature5222can move within the first cavity5272of the housing5270when the solenoid assembly5240is energized and/or de-energized. The contact surface5228of the armature5222defines a groove5227within which an end portion of the armature spring5232is disposed.

The pull rod5212has a first end portion5213and a second end portion5214. The second end portion5214of the pull rod5212is coupled to the armature5222. More particularly, as shown inFIG. 57, the second end portion5214of the pull rod5212has a head5218and defines a retaining ring groove5219within which a retaining ring5220is disposed. The second end portion5214of the pull rod5212is disposed within the lumen5225of the armature5222such that the head5218of the pull rod5212can engage and/or contact the shoulder5226of the armature5222to limit axial movement of the armature5222relative to the pull rod5212in a direction shown by the arrow JJ inFIG. 57.

When the second end portion5214of the pull rod5212is coupled to the armature5222, the retaining ring5220is configured to contact the flange5221of the armature5222to limit axial movement of the armature5222relative to the pull rod5212in a direction shown by the arrow KK inFIG. 57. As shown inFIG. 57, the distance d1between the head5218and the snap ring5220is greater than the distance d2between the shoulder5226of the armature5222and the flange5221of the armature. In this manner, when the second end portion5214of the pull rod5212is coupled to the armature5222, the armature5222can move axially relative to the pull rod5212by a predetermined amount (i.e., the difference between d1and d2). Moreover, as described above, a first end of the armature spring5232is disposed within the groove5236of the end stop5231and a second end of the armature spring5232is disposed within the groove5227of the armature5222. Thus, when the solenoid assembly5230is not energized, the armature5222is biased in a position such that the flange5221is in contact with the snap ring5220. Accordingly, when the solenoid assembly5230is energized, the armature5222initially travels relative to the pull rod5212in the direction shown by the arrow JJ inFIG. 57. When the shoulder5226of the armature5222contacts the head5218of the pull rod5212, the armature5222and the pull rod5212move together until the contact surface5228of the armature engages and/or contacts the end surface5235of the end stop5231. By allowing the armature5222to move relative to the pull rod5212when the solenoid assembly5230is energized, the armature5222can accelerate and thereby generate an impulse force before engaging the pull rod5212. This arrangement can provide more repeatable and/or reliable valve opening performance.

The distance through which the armature5222can move axially relative to the pull rod5212(i.e., the difference between d1and d2) can be any suitable amount. In some embodiments, for example, the difference between the spacing of the head5218and the groove5219(d1) and the thickness of the armature5222(d2) is between 0.015 inches and 0.050 inches. In other embodiments, the difference between d1and d2is approximately 0.030 inches.

As described above, the first end portion5213of the pull rod5212is coupled to second end portion5177I of the intake valve5160I. More particularly, the first end portion5213of the pull rod5212includes a male threaded portion disposed within the female threaded opening5178I of the intake valve5160I. Accordingly, axial movement of the pull rod5212results in axial movement of the intake valve5160I. In some embodiments, a lock nut can be disposed about the first end portion5213of the pull rod5212to limit rotational movement of the pull rod5212relative to the intake valve5160I (i.e., to prevent the pull rod5212from “backing out” of the threaded opening5178I of the intake valve5160I).

In use, when the solenoid coil5242is energized with an electrical current, a magnetic field is produced that exerts a force upon the armature5222in a direction shown by the arrow LL inFIG. 52. The magnetic force causes the armature5222to move relative to (and towards) the solenoid coil5242, as shown by the arrow LL inFIG. 52and the arrow JJ inFIG. 57. As described above, the armature5222initially travels relative to the pull rod5212. When the shoulder5226of the armature5222contacts the head5218of the pull rod5212, and the force exerted by the pull rod5212on the intake valve5160I is greater than the biasing force exerted by the spring5118I, the armature5222and the pull rod5212move together, thereby causing the intake valve5160I to move from the closed position (FIG. 51) to the opened position (FIG. 52). The armature5222and pull rod5212travel together until the contact surface5228of the armature5222engages and/or contacts the end surface5235of the end stop5231. When the solenoid coil5242is energized, the armature5222travels through a distance Sd (i.e., the solenoid stroke as shown inFIG. 51). The distance through which the pull rod5212(and therefore the intake valve5160I) travels is the difference between the solenoid stroke and the difference between d1and d2, as given by equation (6).
Travel=Sd−(d1−d2)  (6)
Thus, the travel of the intake valve5160I can be adjusted by changing the solenoid stroke Sd.

When the solenoid coil5242is de-energized, the force exerted by the intake valve spring5118I causes the intake valve5160I, the pull rod5212and armature5222to travel in a direction opposite the direction shown by the arrow LL inFIG. 52. Additionally, the force exerted by the armature spring5232moves the armature5222relative to the pull rod5212such that the flange5221of the armature5222is in contact with the snap ring5220.

The variable travel actuator5250is configured to selectively vary the distance through which the intake valve5160I travels when moving between the closed and an opened position. More particularly, the variable travel actuator5250is configured to selectively adjust the stroke of the solenoid assembly5230. In this manner, the intake valve5160I can be moved between the closed position and any number of different partially opened positions. Moreover, because the valve actuator5210is electrically operated, the valve5160can be moved between the closed position and an opened position independently from the rotational position of a camshaft or a crankshaft of the engine5100.

As shown inFIG. 50, the variable travel actuator5250includes a motor5262, a drive belt5260and a driven ring5252. As described herein, the variable travel actuator5250is configured to selectively rotate the solenoid assembly5230within the housing5270to adjust the solenoid stroke Sd (see e.g.,FIG. 51). The motor5262includes a drive shaft5263and a drive member5265. The motor5262can be, for example a stepper motor, such as the Model 23Y104S-LWB 2A/phase series stepper motor available from Anaheim Automation, Inc. The motor5262is coupled to the housing5270via a motor housing5264. The motor housing5264aligns the motor6262relative to the housing5270such that the drive member5265is disposed within the second cavity5275of the housing5270.

The driven ring5252includes an outer surface5254having a series of protrusions (e.g., teeth or knurling). The driven ring5252is coupled to the end stop5231of the solenoid assembly5230such that rotation of the driven ring5252results in rotation of the solenoid assembly5230. The driven ring5252can be coupled to the end stop5231in any suitable manner. For example, in some embodiments, the driven ring5252can be coupled to the end stop5231via cap screws, a welded joint, an adhesive, a snap-ring and/or the like. The drive belt5260is disposed about the drive member5265and the outer surface5254of the driven ring5252. In this manner, rotational movement of the drive shaft5263can be transferred to the solenoid assembly5230via the drive belt5260.

A position ring5257is coupled to the driven ring5252such that the position ring rotates with the driven ring5252. The position ring5257includes a protrusion5258(see e.g.,FIG. 58) configured to engage the sensor5266. In this manner, the rotational position of the solenoid assembly5230can be measured electronically. Although the sensor5266is shown as sensing the rotational position of the solenoid assembly5230via contact with the protrusion5258, in other embodiments, the sensor5266can use any suitable mechanism for sensing the position of the solenoid assembly5230. For example, in some embodiments, the sensor5266can include an optical shaft encoder configured to provide an electronic output associated with the rotational position of the solenoid assembly5230.

The variable travel actuator5250is configured to selectively vary the valve travel by moving the intake valve actuator assembly5200between any number of different configurations corresponding to the position of the solenoid assembly5130within the housing5270. For example,FIGS. 51 and 52show the intake valve actuator assembly5200in a first (or full opening) configuration, andFIG. 53shows the intake valve actuator assembly5200in a second (or partial opening) configuration. When the intake valve actuator assembly5200is in the full opening configuration, end surface5235of the end stop5231is spaced apart from a shoulder of the housing5270by a distance d3. The shoulder is identified only as a reference point for purposes of showing the position of the solenoid assembly5230within the housing5270. Thus, when the intake valve actuator assembly5200is in the full opening configuration, the solenoid stroke Sd is at its maximum value. Accordingly, when the solenoid assembly5230is energized, the intake valve5160I moves from the closed position (FIG. 51) to the fully opened position (FIG. 52). When the intake valve5160I is in the fully opened position, each flow opening5168I of the intake valve5160I is substantially aligned with the corresponding intake manifold flow passages5144I and cylinder flow passages5148I.

To move the intake valve actuator assembly5200to another configuration (e.g., the partial opening configuration, as shown inFIG. 53), the motor5262is energized thereby causing rotational motion of the drive shaft5263. The rotational movement of the drive shaft5263is transmitted to the driven ring5252via the belt5260, thereby causing the solenoid assembly5230to rotate within the housing5270, as shown by the arrow MM inFIG. 53. Because the solenoid assembly5230is threadedly coupled to the housing5270, the rotation of the solenoid assembly5230results in axial movement of the solenoid assembly5230within the housing5270, as shown by the arrow NN inFIG. 53.

When the intake valve actuator assembly5200is in the partial opening configuration, end surface5235of the end stop5231is spaced apart from a shoulder of the housing5270by a distance d4that is less than the distance d3. Thus, when the intake valve actuator assembly5200is in the partial opening configuration, the solenoid stroke (not shown inFIG. 53) less than the maximum value Sd. Accordingly, when the solenoid assembly5230is energized, the intake valve5160I moves from the closed position (FIG. 51) to the partially opened position (FIG. 53). When the intake valve5160I is in the partially opened position, each flow opening5168I of the intake valve5160I is partially aligned with the corresponding intake manifold flow passages5144I and cylinder flow passages5148I. Thus, when the intake valve5160I is in the partially opened position, the intake air flow rate through the cylinder head assembly5130is less than the air flow rate through the cylinder head assembly5130when the intake valve5160I is in the fully opened position.

In a similar manner as described above with reference to the intake actuator assembly5200, the exhaust actuator assembly5300is configured to move the exhaust valve5160E between its closed position and its opened position and selectively vary the distance through which the exhaust valve5160E travels when moving between its closed position and an opened position. Similarly stated, the exhaust actuator assembly5300is configured to move the exhaust valve5160E between its closed position (FIG. 59) and any number of different opened positions (e.g.,FIGS. 60 and 61). Referring toFIG. 58, the exhaust actuator assembly5300includes a housing5370that contains a valve actuator5210and a variable travel actuator5250.

The housing5370defines a first cavity5372, a second cavity5375and a third cavity5376. The first cavity5372is defined by a side wall that includes a female threaded portion5373that corresponds to the male threads5246on the solenoid casing5240. In this manner, a portion of the valve actuator5210is movably disposed within the first cavity5372. As described above with reference to the intake actuator assembly5200, a portion the variable lift actuator5250is disposed within the second cavity5375.

As shown inFIGS. 58-61, the third cavity5376contains the exhaust valve spring5118E. The side wall that defines the third cavity5376includes a spring shoulder5377against which a first end of the exhaust valve spring5118E is disposed. A second end of the exhaust valve spring5118E is disposed within a groove5317of a lock nut5316coupled to the first end5213of the pull rod5212. In this manner, the exhaust valve5160E is biased in the closed position within the exhaust valve pocket5138E. By disposing the exhaust valve spring5118E outside of the exhaust valve pocket5138E, the exhaust valve spring5118E is not directly exposed to hot exhaust gases. Additionally, the side wall adjacent the third cavity5376defines a coolant passage5378within which coolant can flow to further maintain the exhaust valve spring5118E and associated components below a desired temperature.

As shown inFIGS. 46 and 47, the housing5370is coupled to the cylinder head5132such that at least a portion of the first cavity5372and the third cavity5376are aligned with the exhaust valve pocket5138E. In this manner, as described above, the valve actuator5210can engage and/or actuate the exhaust valve5160E. As shown inFIG. 58, the housing5370is coupled to the cylinder head5132via a cooling plate5380. The cooling plate5380includes a set of cooling passages5382(only one is identified inFIG. 58), at least one of which is in fluid communication with the coolant passage5378of the housing5370. In this manner, the cooling plate5380can further promote the transfer of heat away from the exhaust valve spring5118E, the valve actuator assembly5210and/or components of the exhaust valve train. Note thatFIGS. 59-61show the housing5270and the cooling plate5380as being spaced apart from the cylinder head5132for purposes of clarity.

The valve actuator5210of the exhaust valve actuator assembly5300is the same as the valve actuator5210disposed within the intake valve actuator assembly5200as shown and described above. Similarly, the variable travel actuator5250of the exhaust valve actuator assembly5300is the same as the variable travel actuator5250disposed within the intake valve actuator assembly5200as shown and described above. Accordingly, the components within and the operation of the valve actuator5210and the variable travel actuator5250are not described below. In other embodiments, the exhaust valve actuator assembly5300can include a valve actuator and/or a variable travel actuator different from the valve actuator5210and/or the variable travel actuator5250, respectively. For example, in some embodiments, the solenoid assembly of the exhaust valve actuator can produce a different opening force than the solenoid assembly5230.

The only substantial difference between the exhaust valve actuator assembly5300and the intake valve actuator assembly5200is that, as described above, the exhaust valve spring5118E is disposed within the housing5370rather than within the exhaust valve pocket5138E. More particularly, as shown inFIGS. 59-61, the lock nut5316is disposed about the first end portion5213of the pull rod5212. In some embodiments, the lock nut5216can limit rotational movement of the pull rod5212relative to the exhaust valve5160E (i.e., to prevent the pull rod5212from “backing out” of the threaded opening5178E of the exhaust valve5160E). The lock nut5316includes a spring grove5317within which an end portion of the exhaust valve spring5118E is disposed. In this manner, as described above, the exhaust valve5160E is biased in the closed position (see e.g.,FIG. 59).

The variable travel actuator5250is configured to selectively vary the exhaust valve travel by moving the exhaust valve actuator assembly5300between any number of different configurations corresponding to the position of the solenoid assembly5130within the housing5370. For example,FIGS. 59 and 60show the exhaust valve actuator assembly5300in a first (or full opening) configuration, andFIG. 61shows the exhaust valve actuator assembly5300in a second (or partial opening) configuration. When the exhaust valve actuator assembly5300is in the full opening configuration, end surface5235of the end stop5231is spaced apart from a shoulder of the housing5370by a distance d5. The shoulder is identified only as a reference point for purposes of showing the position of the solenoid assembly5230within the housing5370. Thus, when the exhaust valve actuator assembly5300is in the full opening configuration, the solenoid stroke Sd is at its maximum value. Accordingly, when the solenoid assembly5230is energized, the exhaust valve5160E moves from the closed position (FIG. 59) to the fully opened position (FIG. 60). When the exhaust valve5160E is in the fully opened position, each flow opening5168E of the exhaust valve5160E is substantially aligned with the corresponding exhaust manifold flow passages5144E and cylinder flow passages5148E.

When the exhaust valve actuator assembly5300is in the partial opening configuration, end surface5235of the end stop5231is spaced apart from a shoulder of the housing5370by a distance d6that is less than the distance d5. Thus, when the exhaust valve actuator assembly5300is in the partial opening configuration, the solenoid stroke (not shown inFIG. 61) less than the maximum value Sd. Accordingly, when the solenoid assembly5230is energized, the exhaust valve5160E moves from the closed position (FIG. 59) to the partially opened position (FIG. 61). When the exhaust valve5160E is in the partially opened position, each flow opening5168E of the exhaust valve5160E is partially aligned with the corresponding exhaust manifold flow passages5144E and cylinder flow passages5148E. Thus, when the exhaust valve5160E is in the partially opened position, the exhaust gas flow rate through the cylinder head assembly5130is less than the exhaust gas flow rate through the cylinder head assembly5130when the exhaust valve5160E is in the fully opened position.

Although the intake valve actuator assembly5200and the exhaust valve actuator assembly5300are shown as having only one partial opening configuration (e.g.,FIGS. 53 and 61, respectively), the intake valve actuator assembly5200and the exhaust valve actuator assembly5300can be moved between the full opening configuration and any number of partial opening configurations. For example in some embodiments, the intake valve actuator assembly5200and/or the exhaust valve actuator assembly5300can adjust the distance between the closed position and the opened position of the intake valve5160I and/or the exhaust valve5160E, respectively, to any value between approximately zero inches and 0.090 inches. By selectively varying the distance between the opened position and the closed position (e.g., the valve travel), the intake valve actuator assembly5200and/or the exhaust valve actuator assembly5300can accurately and/or precisely control the amount and/or flow rate of gas flow into and/or out of the cylinder5103. More particularly, the intake valve and/or exhaust valve travel can be varied in conjunction with the timing and duration of the respective valve opening event to provide the desired gas flow characteristics as a function of the engine operating conditions (e.g., low idle, road cruising conditions or the like). Moreover, because the intake valve5160I and the exhaust valve5160E are not disposed within the cylinder5103when the intake valve5160I and the exhaust valve5160E are in their respective partially opened and/or fully opened positions, the timing of the valve opening can be adjusted without concern for the possibility of valve-to-piston contact. In some embodiments, the control afforded by this arrangement allows the engine gas exchange process to be controlled using only the intake valve5160I and the exhaust valve5160E, thereby removing the need for a throttle valve upstream of the cylinder head5132.

This arrangement allows the valve events and/or engine throttling to be tailored for a particular engine operating condition, as well as for a particular engine performance rating or “package.” For example, in certain situations, a particular base engine design (e.g., a 2.2 liter, V6) is used in many different markets (e.g., Europe, California, other U.S. states, high altitude markets and the like), each having different performance and/or emissions requirements. To accommodate the different markets, manufacturers may change the rating or performance “package” of the base engine by changing certain hardware (e.g., the camshafts, the pistons, the fuel injection system or the like). In some embodiments, the valve systems and methods of control described herein can be used to provide multiple different engine ratings or performance “packages” without requiring that engine hardware be changed.

For example,FIG. 65is a schematic illustration of an engine6100according to an embodiment. The engine6100includes an engine block6102defining at least one cylinder (not identified inFIG. 65). A cylinder head assembly6130is coupled to the engine block6102. The cylinder head assembly6130can be any of the cylinder head assemblies shown and described above, and can include, for example, a tapered valve such as the valves5160I and5160E shown and described above. The engine6100includes an intake valve actuator assembly6200and an exhaust valve actuator assembly6300. The intake valve actuator assembly6200is configured to open the intake valve of the engine6100at a predetermined time, for a predetermined duration and/or at a predetermined amount of valve travel, as described above. The exhaust valve actuator assembly6300is configured to open the exhaust valve of the engine6100at a predetermined time, for a predetermined duration and/or at a predetermined amount of valve travel, as described above.

The engine6100includes an electronic control unit (ECU)6196in communication with the intake valve actuator assembly6200and the exhaust valve actuator assembly6300. The ECU6196is processor of the type known in the art configured to receive input from various sensors (e.g., an engine speed sensor, an exhaust oxygen sensor, an intake manifold temperature sensor or the like), determine the desired engine operating conditions and convey signals to various actuators to control the engine accordingly. As described below, the ECU6196is configured determine the desired valve events (e.g., the opening time, duration of opening and/or valve travel) and provide an electronic signal to the intake valve actuator assembly6200and the exhaust valve actuator assembly6300so that the intake and exhaust valves open and close as desired.

The ECU6196includes a memory component within which a series of calibration tables are stored. The calibration tables can also be referred to as calibration maps and/or data arrays. The calibration tables can include, for example, a table specifying a target fueling level for the engine6100as a function of throttle position, a table specifying a target fuel injector timing and duration as a function of engine operating conditions (e.g., speed and fueling level), a table specifying a target ignition timing as a function of engine operating conditions, and/or the like. The memory of the ECU6196also includes calibration tables associated with the intake valve and/or the exhaust valve.FIGS. 66-68are tabular representations of calibration tables for the intake valve. Although the calibration tables shown inFIGS. 66-68are for the intake valve, the memory of the ECU6196can include similar tables for the exhaust valve.

FIG. 66is a valve travel calibration table6410. The valve travel calibration table6410is a “three dimensional table” that includes a first axis6412specifying the target engine speed (e.g., in revolutions per minute). The valve travel calibration table6410includes a second axis6414specifying the target engine fueling level per operating cycle (e.g., in cubic millimeters of fuel per engine cycle). Although the first axis6412and the second axis6414specify the target speed and fueling level, respectively, in other embodiments, the axes of the valve travel calibration table6410can specify any suitable target engine operating parameter (e.g., target power output, ambient temperature, exhaust oxygen level or the like). The body6416of the valve travel calibration table6410includes the target valve travel setting (in units of percentage of the maximum travel) for each engine speed (from the first axis6412) and each target fueling level (from the second axis6414). In other embodiments, the body6416of the calibration table6410can specify the target valve travel in units of length of travel (e.g., inches), steady state airflow at a given valve travel, or the like. The data values provided in the valve travel calibration table6410are provided for example only and are not intended to limit the data that can be included in the valve travel calibration table6410.

FIG. 67is a valve opening calibration table6420. The valve opening calibration table6420is a “three dimensional table” that includes a first axis6422specifying the target engine speed (e.g., in revolutions per minute). The valve opening calibration table6420includes a second axis6424specifying the target engine fueling level per operating cycle (e.g., in cubic millimeters of fuel per engine cycle). Although the first axis6422and the second axis6424specify the target speed and fueling level, respectively, in other embodiments, the axes of the valve opening calibration table6420can specify any suitable target engine operating parameter (e.g., target power output, ambient temperature, exhaust oxygen level or the like). The body6426of the valve opening calibration table6420includes the target valve opening timing (in units of the angular position of the crankshaft in degrees) for each engine speed (from the first axis6422) and each target fueling level (from the second axis6424). In other embodiments, the body6426of the valve opening calibration table6420can specify the target opening timing in units of time (e.g., milliseconds), relative crankshaft position (e.g., after the fuel injector shuts off), or the like. The data values provided in the valve opening calibration table6420are provided for example only and are not intended to limit the data that can be included in the valve opening calibration table6420.

FIG. 68is a valve duration calibration table6430. The valve opening calibration table6420is a “three dimensional table” that includes a first axis6432specifying the target engine speed (e.g., in revolutions per minute). The valve duration calibration table6430includes a second axis6434specifying the target engine fueling level per operating cycle (e.g., in cubic millimeters of fuel per engine cycle). Although the first axis6432and the second axis6434specify the target speed and fueling level, respectively, in other embodiments, the axes of the valve duration calibration table6430can specify any suitable target engine operating parameter (e.g., target power output, ambient temperature, exhaust oxygen level or the like). The body6436of the valve duration calibration table6430includes the target valve closing timing (in units of the angular position of the crankshaft in degrees) for each engine speed (from the first axis6432) and each target fueling level (from the second axis6434). In other embodiments, the body6436of the valve duration calibration table6430can specify the target valve open duration in units the crank angle period during which the valve is opened, in units of time (e.g., milliseconds), or the like. The data values provided in the valve duration calibration table6430are provided for example only and are not intended to limit the data that can be included in the valve duration calibration table6430.

During operation of the engine6100, the ECU6196can control the valve events (e.g., the opening time, duration of opening and/or valve travel of the intake and/or exhaust valve) using the calibration tables6410,6420and/or6430. More particularly, when the engine is operating at a particular set of operating conditions (e.g., engine speed and fueling level), the ECU6196can determine the target valve travel by interpolating (or “looking up”) the target valve travel in the valve travel calibration table6410based on the target engine speed and the target fueling level. The target engine speed can be, for example, the engine speed as measured by an engine speed sensor. Under certain conditions (e.g., transient conditions), the target engine speed can be a calculated target based on the current measured engine speed and the temporal history of the measured engine speed (e.g., the rate of change of the engine speed). Similarly, the target fueling level can be, for example, the fueling level as measured determined from another calibration table. Under certain conditions (e.g., transient conditions), the target fueling level can be a calculated target based on the current value for the fueling level and the temporal history of the fueling level (e.g., the rate of change of the fueling level).

Similarly, the ECU6196can determine the target valve opening timing by interpolating (or “looking up”) the target valve opening timing in the valve opening calibration table6420based on the target engine speed and the target fueling level. Similarly, the ECU6196can determine the target valve open duration by interpolating (or “looking up”) the target valve duration in the valve duration calibration table6430based on the target engine speed and the target fueling level.

In this manner, the ECU6296, the intake valve actuator assembly6200and/or the exhaust valve actuator assembly6300can collectively control the amount and/or flow rate of gas into and/or out of the cylinder during engine operation. More particularly, the intake valve and/or exhaust valve timing, duration and/or travel can be varied to provide the desired gas flow characteristics as a function of the engine operating conditions (e.g., low idle, road cruising conditions or the like). In some embodiments, the control afforded by this arrangement allows the engine gas exchange process to be controlled using only the intake valve and/or the exhaust valve, thereby removing the need for a throttle valve upstream of the cylinder head. In such embodiments, the “throttle position” as referenced above, does not refer to the position of a throttle valve, but rather refers to a position of an accelerator pedal, which corresponds to a desired fueling level of the engine.

In some embodiments, the ECU6196can include one or more “cold start” calibration tables that include target valve travel, timing and/or duration values for use during engine start up. In some embodiments, for example, the ECU6196can be configured to open the exhaust valve early (e.g., at a crank angle position of less than 140 crank angle degrees after top dead center on the firing stroke) during a start up event. In this manner, the temperature of the exhaust gas exiting the cylinder can be increased, thereby heating up the catalytic converter faster than could be done with standard exhaust valve events.

In some embodiments, the ECU6196can include one or more altitude calibration tables that include target valve travel, timing and/or duration values for use when the engine is operating at high altitudes. For example, in some embodiments, an altitude calibration table can include a first axis that specifies atmospheric pressure.

In some embodiments, the ECU6196can include an idle stability algorithm that adjusts the target valve travel, timing and/or duration values for the valves of a cylinder of a multi-cylinder engine independently from the target valve travel, timing and/or duration values for the valves of an adjacent cylinder of the engine. In this manner, an intake valve of a first cylinder can have a different lift, opening timing and/or duration than an intake valve of a second cylinder. Such an arrangement can allow the engine to maintain idle stability at very low speeds. For example, in some embodiments, such an idle stability algorithm can allow the engine to maintain idle stability at engine speeds below 500 revolutions per minute.

Although the engine6100is illustrated and described as including an ECU6196, in some embodiments, an engine6100can include software in the form of processor-readable code instructing a processor to perform the functions described herein. In other embodiments, an engine6100can include firmware that performs the functions described herein.

While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Where methods described above indicate certain events occurring in certain order, the ordering of certain events may be modified. Additionally, certain of the events may be performed concurrently in a parallel process when possible, as well as performed sequentially as described above. While the embodiments have been particularly shown and described, it will be understood that various changes in form and details may be made.

For example, although the valves5160I and5160E are shown and described above as having a tapered portion, in other embodiments, the valves5160I and/or5160E can be substantially non-tapered. Although the valves5160I and5160E are shown and described above as being disposed outside of the cylinder5103when moved between their respective closed and opened positions, in other embodiments, a portion of the intake valve5160I and/or a portion of the exhaust valve5160E can be disposed within the cylinder5103when in the opened (or partially opened) position.

Although the engine5100is shown and described as including a single cylinder, in some embodiments, an engine can include any number of cylinders in any arrangement. For example, in some embodiments, an engine can include any number of cylinders in an in-line arrangement. In other embodiments, any number of cylinders can be arranged in a vee configuration, an opposed configuration or a radial configuration.

Although movement of the drive shaft5263is shown as being transferred to the solenoid assembly5230via the drive belt5260, in other embodiments, the rotational movement of the drive shaft5263can be transferred to the solenoid assembly5230via any suitable mechanism, such as, for example, hydraulically, via a gear drive, or the like.

Although various embodiments have been described as having particular features and/or combinations of components, other embodiments are possible having a combination of any features and/or components from any of embodiments as discussed above. For example, in some embodiments, a variable travel actuator can selectively vary the valve travel by varying both the valve lash, similar to the variable travel actuator3250, and the solenoid stroke, similar to the variable travel actuator4250.