Control valve bounce limiting mechanism for fuel injectors

A fuel injector control valve assembly is provided that comprises a valve actuating mechanism, a cage member that is operatively connected to the valve actuating mechanism, a poppet valve member that is operatively connected to the cage member and that defines a perimeter and a longitudinal axis, a valve sleeve member that is disposed about the poppet valve member, a shim that includes an upper surface that at least partially makes uninterrupted contact with the cage member and a lower surface that at least partially makes uninterrupted contact with the sleeve member, thereby providing a fluid seal about the perimeter of the poppet valve member, and a bounce limiting mechanism that is adjacent the shim and that is interposed between the cage member and at least one of either the poppet valve member and the valve sleeve member.

TECHNICAL FIELD

The present disclosure relates generally to fuel injectors that use a control valve for controlling the injection of fuel into a combustion chamber of an engine. More specifically, the present disclosure relates to valve bounce limiting mechanisms that help to prevent undesirable after-injections that occur subsequent to a desired main injection event for such fuel injectors.

BACKGROUND

Fuel injection is well known in the art for injecting fuel into a combustion chamber of an engine that is subsequently mixed with air or oxygen and then combusted for powering the engine. Fuel injectors often use control valves that control the timing and duration of a fuel injection event into the combustion chamber. As can be imagined, components of fuel injectors including the control valve may experience forces from other components or from its own inertia that causes the valve member to move. For example, when the control valve contacts another component including a valve seat or an actuating component intended to move the valve into the proper position, the control valve or another operatively connected component may move or bounce. This can lead to undesirable consequences.

By way of further example, the control valve may initiate a desirable main fuel injection event and then be moved to another position in order to stop this injection event. However, because of the forces, velocity and inertia transference of and between the various components including the valve member, the control valve may be unintentionally moved from a position where the fuel injection is prohibited to one where it is allowed due to its unintentional bouncing or other movement. This may lead to secondary, tertiary, or other after-injection events that are not intended and that may lead to an undesirable operation of the engine that leads to other problems such as poor engine performance and increased emissions. Hence, methods and devices for eliminating such valve bounce have been developed and employed.

Some control valve assemblies for fuel injectors use a lift shim that is interposed between components that move relative to each other such as a valve sleeve member and a cage member. Such lift shims have recesses that communicate the fluid that is immediately around the valve body with a pressure relief pocket or the like. These recesses are located on the top and bottom surfaces of the shim that contact the valve sleeve and cage members. It has been discovered that this shim design allows an undesirable amount of valve bounce in some applications.

Therefore, it is desirable to develop a mechanism for preventing or limiting valve bounce for a fuel injector than has yet been devised for such applications.

SUMMARY OF THE DISCLOSURE

A fuel injector control valve assembly is provided that comprises a valve actuating mechanism, a cage member that is operatively connected to the valve actuating mechanism, a poppet valve member that is operatively connected to the cage member and that defines a perimeter and a longitudinal axis, a valve sleeve member that is disposed about the poppet valve member, a shim that includes an upper surface that at least partially makes uninterrupted contact with the cage member and a lower surface that at least partially makes uninterrupted contact with the sleeve member, thereby providing a fluid seal about the perimeter of the poppet valve member, and a bounce limiting mechanism that is adjacent the shim and that is interposed between the cage member and at least one of either the poppet valve member and the valve sleeve member.

A fuel injector assembly is provided that comprises a main injection assembly including: a housing that defines a pressurized fuel chamber, a nozzle assembly that includes a check valve assembly, and a control valve assembly including: a valve actuating mechanism, a cage member that is operatively connected to the valve actuating mechanism, a poppet valve member that is operatively connected to the cage member and that defines a perimeter and a longitudinal axis, a valve sleeve member that is disposed about the poppet valve member, an inner shim that includes an upper surface that at least partially makes uninterrupted contact with the cage member and a lower surface that at least partially makes uninterrupted contact with the sleeve member, thereby providing a fluid seal about the perimeter of the poppet valve member, and an outer shim that is taller than the inner shim along the longitudinal axis and that makes uninterrupted contact with at least one of the cage member and the valve sleeve member and that is immediately adjacent the inner shim.

A fuel injector assembly is provided that comprises a main injection assembly including: a housing that defines a pressurized fuel chamber, a nozzle that includes a check valve assembly, and a control valve assembly including: a valve actuating mechanism, a cage member that is operatively connected to the valve actuating mechanism, a poppet valve member that is operatively connected to the cage member and that defines a perimeter and a longitudinal axis, a valve sleeve member that is disposed about the poppet valve member, and wherein the cage member includes a lower surface and the poppet valve member includes an upper surface, wherein the lower surface interfaces with the upper surface, and the lower surface of the cage member and the upper surface of the poppet valve member are configured to provide a separable joint between the poppet valve member and the cage member and at least one of the cage member and poppet valve member defines a groove that communicates only with a surface that forms the separable joint.

DETAILED DESCRIPTION

Many engines now use an electronic control unit or module that manages the fuel system of the engine. More specifically, the electronic control module (ECM) meters the timing and duration of the injection of fuel into a combustion chamber. The amount of fuel injected may be altered by changing the electric signal sent to any one fuel injector unit. When a control valve assembly is present in the fuel injector, a solenoid may be used to effectuate opening and closing of the control valve, which in turn, leads to the desired amount of fuel being injected into the combustion chamber. The electric signal in such a case may be a voltage that energizes the solenoid for a precise period of time. This opens the control valve. When the signal is removed, the solenoid de-energizes and the control valve closes. The voltage signal may be a 105 volt signal in some applications. Of course, the timing of the voltage signal may also control the timing of the fuel injection.

The ECM is instrumental in controlling the injection of fuel into the combustion chamber in order to optimize various performances of the engine. One such performance is the limiting of emissions. A FRC fuel position is determined to limit the amount of fuel that is injected into a certain amount of air to prevent increasing emissions past an allowable limit. This limit is based on the boost pressure present in the air meaning that as the boost pressure increases, then the FRC fuel position also increases. The rated fuel position is also determined based on the horsepower rating of the engine. The electronic control of the rated fuel position is similar to what was once achieved using rack stops and a torque spring on a mechanically governed engine. This rated fuel position also provides the horsepower and torque curves for a specific horsepower rating. These limits are typically programmed by the engine manufacturer into the personality module of the ECM, helping to prevent tampering by the end user that could lead to undesirable emissions of the engine.

The timing of the injection may be determined based on various engine parameters including the engine load, speed etc. The ECM is able to determine the top center position of any cylinder from the signal that is provided by an engine speed or timing sensor as is known in the art. The ECM then calculates when the fuel injection should occur for any cylinder relative to the top center position. Then, the ECM provides the signal to the fuel injector at the appropriate time for causing the fuel injection into the combustion chamber of the cylinder.

Referring now toFIG. 1, an example of a portion of an engine that may be controlled by an ECM and that may include a bounce limiting mechanism according to any of the embodiments discussed herein is shown. The bounce limiting mechanism cannot be clearly seen with reference toFIG. 1thru6but will be discussed in more detail with reference toFIG. 7thru11. It should be noted that the fuel injector and associated engine parts depicted inFIG. 1thru6are provided only as an example and that the configuration of a fuel injector and the manner in which fuel pressurization is achieved for injection may be altered as desired and may include anything known or that will be devised in the art including mechanically pressurized fuel injectors, hydraulically pressurized fuel injectors, common rail fuel injectors, etc. Hence, any discussion ofFIG. 1thru6is merely intended to provide context and understanding on how some fuel injectors and control valve assemblies may work that employ a bounce limiting mechanism as is disclosed in the present disclosure and may not actually use such a bounce limiting mechanism depending on the application.

The engine is shown inFIG. 1to comprise a fuel injector assembly100, a rocker arm assembly102, a cam shaft104and an adjustment nut106. Though not shown inFIG. 1, the cam shaft104is driven by an idler gear that is in turn driven by a front gear train by the crankshaft gear. The gears of the front gear train are timed properly to provide the proper relationship between piston and valve movement. This timing is achieved by correctly aligning the timing marks of the gears during assembly. Typically, the cam shaft has three cam shaft lobes for each cylinder. Two of these lobes operate the opening and closing of the intake and exhaust valves. The third lobe108provides the mechanical force necessary to pressurize the fuel in the fuel injector assembly100as will be explained in further detail momentarily.

In operation as the cam shaft104rotates, the third lobe108contacts the roller curved follower surface110of the rocker arm assembly102, which causes the rocker arm to pivot upwardly about its pivot point112on the right side of the pivot point112. This causes the rocker arm to pivot downwardly on the left side of the pivot point112, exerting force on the tappet114of the fuel injector assembly100, while also compressing the return spring116. The tappet114extends further into the fuel injector assembly100causing pressurization of the fuel. The adjustment nut106is located on top of the yoke118of the rocker arm assembly102that is used to connect the tappet114to the rocker arm assembly102. Rotating the nut106causes the nut106to travel upwardly or downwardly on the threaded end120of the tappet114, which may affect the amount of travel of the tappet or set the desired position of the plunger (not shown) in the injector. After the third lobe108passes the curved follower surface of the rocker arm assembly102, the return spring116will cause the rocker arm on the left side to pivot upwardly and return to its original position.

The ECM (not shown) typically controls the operation of the control valve assembly122through four stages for this type of fuel injector assembly100. These stages include pre-injection, injection, end-of-injection, and fill. As will be shown with reference toFIG. 2thru6, the fuel injector assembly uses a plunger that is disposed in a pressurized fuel chamber defined by a barrel or housing to pressurize the fuel to a pressure suitable for injection into the combustion chamber.

Focusing now onFIG. 2, it shows the fuel injector assembly100includes the main injector assembly124and the control valve assembly122. The components of the main injector assembly124include the tappet114, the plunger126, the housing128and the nozzle assembly130. The nozzle assembly130includes a nozzle housing132, check valve assembly134, a check valve return spring136, and nozzle tip138. The cartridge valve or control valve assembly122includes the solenoid140, armature142, poppet valve member144, a valve sleeve member146, an over-travel spring148, and a main return spring150.

The fuel injector assembly may be mounted in a bore disposed in the cylinder head of the engine which has an integral fuel supply passage (not shown). An injector sleeve (not shown) may also be provided that separates the fuel injector assembly from the engine coolant in the water jacket. Some engines use a stainless steel sleeve. Such sleeves may fit into the cylinder head with a light press fit.

As shown inFIG. 2, the fuel injector assembly100defines a series of passages that are interconnected or in fluid communication with each other and may be selectively separated from each other by the control valve122. That is to say, the fluid communication between the various passages may be turned on and off using the control valve122.

Starting at the nozzle tip138, it defines an injection passage152that surrounds the needle154of the check valve assembly134. The injection passage152is in fluid communication with a feed passage156that extends upwardly through the nozzle assembly130and that is in fluid communication with the pressurized fuel chamber158that is defined by the housing128of the main injector assembly124. Immediately above this space is the plunger126that may move downward and pressurize the fuel as will be described in further detail later herein. A reservoir160is in fluid communication with the pressurized fuel chamber158just to the left of the feed passage156. A first exhaust passage162is in fluid communication with the reservoir160and leads to a control valve chamber164that is disposed around the perimeter of the grooved portion166of the poppet valve member144. This control valve chamber164is in fluid communication with a second exhaust passage168that returns to a fuel tank or reservoir (not shown) at low pressure. The poppet valve member144selectively interrupts the fluid communication between the first and second exhaust passages in a manner that will be described momentarily.

Looking now atFIG. 3, the fuel injector assembly100is shown in its pre-injection configuration. Initially, the tappet114and plunger126are at their topmost position, naturally biased to this position by the return spring116. At this position, the volume of fuel present in the pressurized fuel chamber158is at its greatest. At this time, the ECM does not send a voltage signal to the solenoid140of the control valve assembly122, meaning that the solenoid is not energized and the poppet valve member144, armature142and any other components therebetween are naturally biased by the main and over-travel return springs150,148into their lowest position along the longitudinal axis A of the control valve assembly122, which is defined by the various components such as the poppet valve member144that have substantially cylindrical configurations. Other configurations of these components are considered within the scope of the present disclosure.

As a consequence, the groove166of the poppet valve member144is in simultaneous fluid communication with the first exhaust passage162, control valve chamber164, and second exhaust passage168. This establishes an open position for the poppet valve member144and control valve assembly122as will now be explained. The check valve134of the tip138is naturally biased to a closed position by the check valve return spring136. This check valve134remains closed until enough fuel pressure is supplied to the angled surface170of the needle154of the check valve. As the plunger126and tappet114move downwards (see arrows172,174) into the pressurized fuel chamber158as the rocker arms pivots down on the tappet, the pressure of the fuel is not increased significantly in the fuel injector assembly and therefore the check valve remains closed. This is true because the fuel is free to flow from the pressurized fuel chamber158, to the reservoir160, through the first exhaust passage162to the control valve chamber164past the open poppet valve member144, and finally through the second exhaust passage168(see arrows176) to a low pressure fuel reservoir (not shown) via the fuel supply passage in the cylinder head (not shown).

Looking now atFIG. 4, the injection stage and configuration of the fuel injector assembly100in this stage is shown. This stage immediately follows the pre-injection stage just described with reference toFIG. 3. As the plunger126moves downwardly, the ECM sends a voltage signal to the solenoid140of the control valve assembly122, which creates a magnetic field that attracts the armature142, moving it upwards against the return spring forces. This causes the other components of the control valve assembly122to also move upwards including the poppet valve member144(see arrow178) until it impinges on the poppet valve seat180formed by central bore of the valve sleeve member146. At this time, the poppet valve member144is in the closed position blocking any flow of fuel from the first exhaust passage162to the poppet valve chamber164and to the secondary exhaust passage168that leads to the low pressure fuel reservoir (not shown).

Consequently, the plunger126and tappet114continue to move downwards (see arrows172,174), which results in a high pressurization of the fuel in the pressurized fuel chamber158of the main injection assembly. This pressure may reach 5 to 10 ksi, which causes the fuel to flow through the feed passage156to the injection passage152(see arrows184) with enough force at the angled surface170at the tip of the needle154of the check valve134to overcome the force of the check valve return spring136, causing the check valve to open by moving the needle away from the needle seat182(see arrow186) and then fuel sprays out of the nozzle tip138into the combustion chamber (not shown). This is the start of the injection and continues until the ECM triggers opening of the control valve assembly that stops the injection.

FIG. 5illustrates the fuel injector assembly100in the end of injection stage or configuration. The injection is maintained while the plunger126moves downward as explained with reference toFIG. 4and the energized solenoid140keeps the poppet valve member144seated against the valve seat180, that is to say, in a closed configuration. When the ECM determines that injection should be stopped, the voltage signal to the solenoid is reduced to zero. As a result, the magnetic force pulling up on the poppet valve member144through the armature142and other components therebetween, is removed, allowing the return springs148,150to move the poppet valve member downwards along the longitudinal axis A (see arrow188). Once the poppet valve member144opens by moving away from the valve seat180, high pressure fuel from the pressurized fuel chamber158may flow (see arrows190) through the reservoir160, first exhaust passage162, around the poppet valve member144into the control valve chamber164, second exhaust passage168, then into the fuel supply passage (not shown) and finally into the low pressure fuel reservoir (not shown).

As a result, a rapid drop of pressure in the main injection assembly124occurs and the check valve134closes as the needle154moves downward (see arrow192), biased by the check valve return spring136and shuts off on the valve seat. This may occur once the injection pressure drops below 5 ksi. This ends the injection stage. Sometimes, the inertia of the various components of the control valve assembly122including the return springs148,150, may cause a bouncing or oscillating movement of the poppet valve member144that may cause after-injections as described earlier herein. However, a bounce limiting mechanism may be present in this injector assembly that helps prevent this as will be described later herein.

At this point, the pressurized fuel chamber158is mostly empty, needing to be refilled.FIG. 6shows the fuel injector assembly100in its fill configuration. The tappet114is forced upward (see arrow194) by the return spring116as the third lobe (not shown) is no longer pushing down on the tappet114. This also causes the plunger126to move upward (see arrow196), causing a vacuum or other pressure that is less than the fuel supply pressure to be present in the pressurized fuel chamber158. This causes fuel to flow from the fuel reservoir (not shown) through the fuel supply passage (not shown) into the second exhaust passage168(see arrows198). This direction is reversed from the pre-injection direction. Thus, the exhaust passages become fill passages162,168. The poppet valve member144is in the open position, allowing the fuel to enter the control valve chamber164, bypass the open poppet valve member144, and flow into the first fill passage (see arrows199). Finally, the fuel then enters the reservoir160and then the pressurized fuel chamber158. This continues until the plunger126and tappet114reach their topmost position. The fuel injector assembly100is now ready for the cycle to repeat itself starting with the pre-injection stage.

It should be noted that the pressurized fuel chamber in this embodiment is pressurized mechanically by the plunger, tappet and cam shaft. However, this pressurization may be caused by a plunger moved hydraulically. In yet other embodiments, this pressurization may achieved by providing direct fluid communication between the pressurized fuel chamber and a high pressure fuel source such as a common rail, etc.

Turning the reader's attention now toFIGS. 7 and 8, a fuel injector assembly that includes a main injection assembly similar to what has been previously described with reference toFIG. 1thru6may use a control valve assembly200similar to what is depicted inFIGS. 7 and 8. The control valve assembly200may include a valve actuating mechanism202, a cage member204that is operatively connected to the valve actuating mechanism202, a poppet valve member206that is operatively connected to the cage member204and that defines a perimeter208and a longitudinal axis A, a valve sleeve member210that is disposed about the poppet valve member206, and an inner shim212. The inner shim212may include an upper surface214that at least partially makes uninterrupted contact with the cage member204and a lower surface216that at least partially makes uninterrupted contact with the sleeve member210, thereby providing a fluid seal about the perimeter208of the poppet valve member206. That is to say, there are no flow paths provided on the upper and lower surfaces of the inner shim. A fluid drain line218may also be seen.

The valve actuating mechanism202may include the use of a solenoid, a piezoelectric device, or any other valve actuating mechanism known or that will be devised in the art.

The control valve assembly200may further comprise an outer shim220that is taller than the inner shim212along the longitudinal axis A and that makes uninterrupted contact with the valve sleeve member210. In this embodiment, the cage member204includes an upper surface222and the outer shim220is positioned adjacent the upper surface222of the cage member204and forms a gap224between the outer shim220and the upper surface222of the cage member204, creating a bounce limiting mechanism using squeeze film damping. This gap may be on the order of 0.1 to 0.5 mm. Other bounce limiting mechanisms may be used as will be described later herein. For this embodiment, the outer shim220sits on the upper surface226of the sleeve member210and is immediately adjacent the inner shim, making or nearly making contact with the inner shim. Also, the upper and lower surfaces of the outer shim lack any recesses to allow liquid to flow by it.

For this embodiment, the inner shim212and outer shim220are made from separate components. However, they may be made out of a unitary piece of material or may comprise separate components that are adhered to each other, preventing movement of the inner and outer shim members relative to each other along the longitudinal axis A. When they are made from separate components and are not adhered to each other, then the inside upper corner228of the outer shim220may be chamfered, allowing hydraulic forces to push the outer shim220in a downward direction as the cage member204approaches the poppet valve member206.

For this embodiment, the lower surface306of the cage member204(seeFIGS. 7-9) interfaces with the upper surface310of the poppet valve member206(seeFIGS. 7-9), and the lower surface306of the cage member204and the upper surface310of the poppet valve member206are configured to provide a separable joint between the poppet valve member206and the cage member204. An explanation of the structure leading to this separable joint is forthcoming. This separable joint may not be present in other embodiments.

The control valve assembly200ofFIGS. 7 and 8may operate in the following manner to achieve the closed configuration as shown in these figures. First, a command voltage is applied across the solenoid202to initiate the creation of a magnetic force. Second, the poppet valve member206, the pillar member230, the cage member204, the spacer member232, and the armature member234moves as one unit as the poppet valve member206moves through its lift distance236to the poppet seat238. This is true because the armature234, spacer member232, and the cage member204are bolted together, forcing them to move together. The pillar member230is biased upwardly by the auxiliary spring240, which causes the poppet valve member to also move upwardly through its bolted connection to the pillar member230. This illustrates how the poppet valve member206may be operatively connected to the armature234or other valve actuating mechanism202but other operative connections are possible such as having a solid or rigid connection between the armature and the poppet valve member.

The motion of the poppet valve member206stops as the poppet valve member reaches its seat238. This causes the injection of fuel into the combustion chamber by the fuel injector assembly. However, the cage member204, the spacer member232and the armature234may continue to move as it moves through the Assisted Valve Opening (AVO) distance (see243).

When it is desired to end injection, the command voltage ends and the magnetic force begins to decay. The timing spring244force begins to push the cage member204, spacer member232and armature234downwardly. These components move until the AVO distance243is exhausted, causing the poppet valve member204and pillar member230to move downwardly until the poppet valve member204moves off of the poppet seat238and back through the lift distance236until it reaches its original starting position. At this point the poppet valve member and the pillar member as well as the cage member, spacer member, and armature subassembly can oscillate or bounce in an uncontrollable manner which may cause valve performance problems. The bounce limiting mechanism may help to eliminate such problems by slowing the approach of the cage member to the poppet valve member.

Another proposed solution to this problem is to provide another bounce limiting mechanism by adding a fluid volume element between the poppet valve member and the cage member. This bounce limiting mechanism is illustrated byFIGS. 9 and 10that disclose a control valve assembly300that is similarly constructed and operated as the control valve assembly200ofFIGS. 7 and 8except for the following differences. The outer shim is eliminated and a single shim302is kept. In some embodiments, no shim may be needed or desired.

The cage member304includes a lower surface306and the poppet valve member308includes an upper surface310, wherein the lower surface306interfaces with the upper surface310, and the lower surface306of the cage member304and the upper surface310of the poppet valve member308are configured to provide a separable joint between the poppet valve member and the cage member and at least one of the cage member304and poppet valve member308defines a groove312that communicates only with a surface306,310that forms the separable joint. For this embodiment, both the cage member304and the poppet valve member308have such grooves312,312′.

Closer inspection of the geometry as best seen inFIG. 10shows that the lower surface306of the cage member304defines a groove312having sidewalls314and the upper surface310of the poppet valve member308defines a groove312′ having sidewalls314′ and the sidewalls of one groove align with the sidewalls of the other groove. This means that the grooves share the same width. The groove312of the cage member defines a depth D312along the longitudinal axis A and the groove312′ of the poppet valve member defines a depth D312′ along the longitudinal axis A, wherein the depth of the groove of the valve member is greater than the depth of the groove of the cage member. The grooves may have a width of approximately 1.5 mm and a depth of 1.5 mm. In some embodiments, the depth of the grooves may be different from the cage member to the valve member or the same. In yet other embodiments, the depth groove of the cage member may be greater than that of the valve member, etc. Also, the widths of the grooves may not be aligned and/or may have different widths than each other, etc.

It is to be understood that the grooves may have a substantially circular annular shape that is rotated about the longitudinal axis A but other configurations are considered to be within the scope of the present disclosure.

This bounce limiting mechanism would have little to no effect on the upward valve and armature motion or on the performance of the valve in the fully closed state. It may have a limited dampening effect on the valve and armature as they move downward from the fully closed state to the fully open state.

As the valve reaches its fully open state, over travels, and begins to move upward and back to its initial position, the fluid squeezed between the grooves will have a dampening effect and absorb some of the energy of the valve-armature system and limit the motion of the system. As a result, the ability of an extended or secondary injection event to form will also be limited.

INDUSTRIAL APPLICABILITY

In practice, a control valve assembly that uses any of the bounce limiting mechanisms described herein may be provided, sold, manufactured, bought etc. to refurbish or remanufacture existing fuel injector assemblies to help limit the problem of valve bounce. Similarly, a fuel injector assembly may also be provided, sold, manufactured, bought, etc. to provide a new fuel injector that is less prone to valve bounce than has been yet made available to the public. The fuel injector assembly may be new or refurbished, remanufactured, etc.

Referring back toFIGS. 7-10, the fuel injector control valve assembly200,300may comprise a valve actuating mechanism202, a cage member204,304that is operatively connected to the valve actuating mechanism202, a poppet valve member206,308that is operatively connected to the cage member204,304, and that defines a perimeter208and a longitudinal axis A, a valve sleeve member210that is disposed about the poppet valve member, and a shim302,212,220.

The shim212may include an upper surface214that at least partially makes uninterrupted contact with the cage member204and a lower surface216that at least partially makes uninterrupted contact with the sleeve member210, thereby providing a fluid seal about the perimeter208of the poppet valve member206. Also, a bounce limiting mechanism may be provided that is interposed between the cage member204,304and at least one of either the poppet valve member206,308and the valve sleeve member210. The bounce limiting mechanism may include the inner and outer shim ofFIGS. 7 and 8or the groove ofFIGS. 9 and 10.

When using a suitable bounce limiting mechanism such as the groove312ofFIGS. 9 and 10, the amount of valve bounce may be reduced as shown inFIG. 11. This is a graph of the position of a valve member versus time during various stages of a fuel injector. One curve (dotted line) shows the amount of undesirable valve travel at the end of injection and the subsequent undesirable valve bounce that occurs thereafter. A first and a second after-injection event are also common. Conversely, the second curve (solid line) shows that the amount of over travel of the valve member is reduced when the bounce limiting mechanism is employed and subsequent after-injection events are also reduced.

It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the apparatus and methods of assembly as discussed herein without departing from the scope or spirit of the invention(s). Other embodiments of this disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the various embodiments disclosed herein. For example, some of the equipment may be constructed and function differently than what has been described herein and certain steps of any method may be omitted, performed in an order that is different than what has been specifically mentioned or in some cases performed simultaneously or in sub-steps. Furthermore, variations or modifications to certain aspects or features of various embodiments may be made to create further embodiments and features and aspects of various embodiments may be added to or substituted for other features or aspects of other embodiments in order to provide still further embodiments.