Patent Description:
Internal combustion engines typically include a plurality of reciprocating pistons within combustion cylinders in a cylinder block. Combustion of a mixture of air and fuel causes the pistons to move in response to a rapid pressure and temperature rise in the combustion cylinders to rotate a crankshaft. Internal combustion engines commonly operate on a four-stroke cycle including an intake stroke of the pistons, a compression stroke, an expansion stroke, and an exhaust stroke. Various engine configurations alternatively employ a two-cycle pattern.

The combustion of fuel and air generates heat within the combustion cylinders that is transferred to the metallic surfaces of the engine, including cylinder or cylinder liner walls, the pistons, an engine head, etc. Various strategies for dissipating heat of combustion include conveyance of liquid coolant through the cylinder block, as well as conveyance of oil to surfaces of the pistons and associated apparatus.

In some internal combustion engines, notably compression-ignition diesel engines, piston cooling jets are commonly positioned below the pistons to spray engine oil at the pistons in order to keep the pistons from overheating. Engines traditionally utilize a fixed displacement oil pump that operates linearly in relation to engine speed. As a result, the oil pressure that is provided to spray cooling oil by way of the piston cooling jets can vary with pump and engine speed. When an engine is operating at a higher engine load, the heat of combustion can be sufficient that piston cooling by way of piston cooling jets is indispensable to operation. In other instances, the need for oil spray may be much reduced. Certain attempts have been made to regulate piston cooling jet spray to avoid wasting energy by way of wasted oil pressure and oil consumption when the need for piston cooling is reduced. One such strategy utilizes ball-spring check valves in each individual jet. This strategy can impact flow characteristics of oil conveyed through the jet, sometimes undesirably.

One known piston cooling jet configuration is known from <CIT>. In Berlinger a cooling nozzle includes a non-metallic body and a metallic insert. A passage configuration through the cooling nozzle apparently provides a smooth, reduced turbulence and reduced eddy flow pattern. The cooling nozzle is stated to be low cost and efficient. While the cooling jet/nozzle configuration of Berlinger undoubtedly has applications, there is always room for improvement and development of alternative strategies.

In one aspect, an engine includes a cylinder block having formed therein a plurality of cylinders extending between a top deck surface and a bottom block surface, and arranged between a front block end, and a back block end. The cylinder block further has formed therein a main oil gallery extending longitudinally between the front block end and the back block end, a spray jet gallery, a plurality of oil feed holes fluidly connected to the spray jet gallery, and a cross-hole fluidly connected to the main oil gallery and extending to the spray jet gallery. The cylinder block still further includes a plurality of oil spray jets each fluidly connected to one of the plurality of oil feed holes and oriented to spray oil upwardly into one of the plurality of cylinders, and an oil admission valve supported in the cylinder block and movable between a closed position where the oil admission valve blocks the spray jet gallery and each of the plurality of oil feed holes from the cross-hole, and an open position. <CIT> discloses an example of such an engine.

In another aspect, a cylinder block includes a cylinder block casting having formed therein a plurality of cylinders extending between a top deck surface and a bottom block surface, and arranged between a front block end, and a back block end. The cylinder block casting further has formed therein a main oil gallery extending longitudinally between the front block end and the back block end, a spray jet gallery extending longitudinally between the front block end and the back block end, a plurality of oil feed holes each opening from the spray jet gallery at a location longitudinally aligned with one of the plurality of cylinders, and a cross-hole fluidly connected to the main oil gallery and extending to the spray jet gallery. The cylinder block casting still further includes an outer casting surface, and a cast-in valve body forming a valve bore extending from the cross-hole to the outer casting surface.

In still another aspect, an engine includes a cylinder block having formed therein a plurality of cylinders extending between a top deck surface and a bottom block surface, and arranged between a front block end, and a back block end. The cylinder block further has formed therein a main oil gallery extending longitudinally between the front block end and the back block end, a spray jet gallery, a plurality of oil feed holes each fluidly connected to the spray jet gallery and longitudinally aligned with one of the plurality of cylinders, and a cross-hole fluidly connected to the main oil gallery and extending to the spray jet gallery. The cylinder block still further includes an oil admission valve supported in the cylinder block and movable between a closed position where the oil admission valve blocks the spray jet gallery and each of the plurality of oil feed holes from the cross-hole, and an open position.

Referring to <FIG>, there is shown an internal combustion engine <NUM>, according to one embodiment. Engine <NUM> includes a cylinder block <NUM> having a one-piece casting <NUM>. Cylinder block <NUM> and cylinder block casting <NUM> are referred to interchangeably herein at times. Cylinder block <NUM> has formed therein a plurality of cylinders <NUM> extending between a top deck surface <NUM> and a bottom block surface <NUM>. Cylinders <NUM> are arranged between a front block end <NUM>, and a back block end <NUM>. In the illustrated embodiment cylinders <NUM> are six in number and are in an inline arrangement between front block end <NUM> and back block end <NUM>. In other embodiments, cylinders <NUM> could be in a different arrangement such as a V-pattern, and could be of any number. Cylinder block <NUM> further forms a crankcase <NUM>, and a plurality of crank bearings <NUM> are coupled to cylinder block <NUM> to rotatably journal a crankshaft in a generally conventional manner. A first lateral side <NUM> of cylinder block <NUM> is shown at <NUM> and a second lateral side of cylinder block <NUM> is shown at <NUM>. First lateral side <NUM> and second lateral side <NUM> can also be understood as opposite lateral sides of crankcase <NUM>.

Although not illustrated in <FIG>, those skilled in the art will appreciate that each of cylinders <NUM> may be equipped with a piston, the pistons being coupled with a crankshaft by way of connecting rods in a generally conventional manner. Engine <NUM> may also include a front gear train positioned at front block end <NUM> and a back gear train positioned at back block end <NUM>, neither of which is illustrated. A front gear train could include a flywheel. A back gear train could include various gears for operating auxiliary equipment including a pump gear, a cam gear, and still others. A block flange <NUM> for mounting of gear train components is positioned at back block end <NUM>. It should be appreciated that the terms "front" and "back" are used herein only in an illustrative sense, and should not be taken to require any particular orientation or arrangement of cylinder block <NUM> or associated components in engine <NUM>. The positioning of components of a back gear train and a front gear train could be varied or reversed from that described. Engine <NUM> can be compression-ignited, structured to operate on a liquid fuel such as a liquid diesel distillate fuel that is directly injected by way of fuel injectors each positioned to extend into one of cylinders <NUM> and supported in an engine head. In other embodiments, engine <NUM> could be spark-ignited, prechamber-ignited, dual fuel liquid pilot-ignited, or have a variety of other configurations or operating strategies.

Referring also now to <FIG>, cylinder block <NUM> further has formed therein a main oil gallery <NUM> extending longitudinally between front block end <NUM> and back block end <NUM>. Cylinder block <NUM> further has formed therein a spray jet gallery <NUM>. Spray jet gallery <NUM> may also extend longitudinally between front block end <NUM> and back block end <NUM>. Also in the illustrated embodiment main oil gallery <NUM> is upon first lateral side <NUM> of crankcase <NUM> and spray jet gallery <NUM> is upon second lateral side <NUM> of crankcase <NUM>. A plurality of spray jet locations <NUM> are associated with a plurality of oil spray jets <NUM> each longitudinally aligned with one of cylinders <NUM> and structured to spray oil upwardly at or towards an underside of pistons within cylinders <NUM>, as further discussed herein.

Cylinder block <NUM> further has formed therein a plurality of oil feed holes <NUM> fluidly connected to spray jet gallery <NUM>, and a cross-hole <NUM> fluidly connected to main oil gallery <NUM> and extending to spray jet gallery <NUM>. A total of one oil feed connection may extend between main oil gallery <NUM> and spray jet gallery <NUM> and is formed by cross-hole <NUM>. Put differently, the sole fluid connection between main oil gallery <NUM> and spray jet gallery <NUM> may be one cross-hole <NUM>. Also in the illustrated embodiment spray jet gallery <NUM> includes a forward segment <NUM> arranged to feed oil to a forward set of oil feed holes <NUM>, and a back segment <NUM> arranged to feed oil to a back set of oil feed holes <NUM>. Cross-hole <NUM> may be approximately half-way fore and aft between front block end <NUM> and back block end <NUM> and may fluidly connect to spray jet gallery <NUM> at a location that is longitudinally between the forward set of oil feed holes <NUM> and the back set of oil feed holes <NUM>. Oil feed holes <NUM> may each be oriented so as to open downwardly from spray jet gallery <NUM>. Oil feed holes <NUM> may be arranged on-center with the respective one of cylinders <NUM> in some embodiments, meaning a center axis of each oil feed hole <NUM> is substantially aligned fore and aft with a center axis of one of cylinder <NUM>.

Engine <NUM> further includes a plurality of oil spray jets <NUM> each fluidly connected to, and typically fitted into, one of oil feed holes <NUM> and oriented to spray oil upwardly into one of cylinders <NUM>. As can best be seen from <FIG>, each of oil spray jets <NUM> can include an elongate, tubular structure having a jet inlet <NUM> within an oil feed hole <NUM>, and a jet outlet <NUM> positioned within a cylinder <NUM>. <FIG> also illustrate a cylinder liner <NUM> forming in part the combustion space of the associated cylinder <NUM>.

Engine <NUM> still further includes an oil admission valve <NUM> supported in cylinder block <NUM> and movable between a closed position where oil admission valve <NUM> blocks spray jet gallery <NUM> and each of oil feed holes <NUM> from cross-hole <NUM>, and an open position where oil admission valve <NUM> does not block spray jet gallery <NUM> and oil feed holes from cross-hole <NUM>. The oil admission valve <NUM> is, according to the invention, a three-way valve positioned fluidly between forward segment <NUM> and back segment <NUM> of a spray jet gallery <NUM>. Engine <NUM>, and in particular cylinder block casting <NUM>, may further include a cast-in valve body <NUM>. Cylinder block casting <NUM> further includes an outer casting surface <NUM> (a block outer surface). Cast-in valve body <NUM> forms a valve bore <NUM>, and a valve seat <NUM>. Valve bore <NUM> extends from cross-hole <NUM> to outer casting surface <NUM>. Valve seat <NUM> is located fluidly between cross-hole <NUM> and spray jet gallery <NUM>. Also in the illustrated embodiment cast-in valve body <NUM> includes a projecting valve boss <NUM> having a boss end surface <NUM>. Boss end surface <NUM> extends peripherally around valve bore <NUM> and forms a part of outer casting surface <NUM>. It can also be seen from <FIG> that a recess <NUM> is formed in valve boss <NUM>.

An oil admission valve according to the present disclosure may be the sole fluid connection control between cross-hole <NUM> and spray jet gallery <NUM>. As will be further apparent from the following description, oil admission valve <NUM> may operate passively, in response to an oil pressure supplied by way of cross-hole <NUM>, or actively and be electrically actuated. Referring also now to <FIG>, engine <NUM> may further include a spring biaser <NUM>, for example a coil spring, biasing oil admission valve <NUM> toward the closed position. Oil admission valve <NUM> may include a valve member <NUM>. Oil admission valve <NUM>, namely valve member <NUM> in the illustrated embodiment, may include an opening hydraulic surface <NUM> exposed to a fluid pressure of cross-hole <NUM>. Opening hydraulic surface <NUM> is in contact with valve seat <NUM> at the closed position. Oil admission valve <NUM> is also understood to define a valve axis of reciprocation <NUM>. Valve axis of reciprocation <NUM> may be colinear with a central bore axis (not numbered) of valve bore <NUM>. Cross-hole <NUM> also defines a cross-hole center axis <NUM>. Valve axis of reciprocation <NUM> intersects cross-hole axis <NUM>, as can been seen in <FIG>, in the illustrated embodiment.

It will be recalled oil admission valve <NUM> contacts valve seat <NUM> at the closed position. Opening hydraulic surface <NUM> may be planar, and valve seat <NUM> may be a flat seat. In other embodiments a conical opening hydraulic surface and a conical valve seat, spherical surfaces, or still another arrangement and/or structure might be used. A slide-type spool valve, a poppet valve, or still other valve configurations employing one or more valve members, may fall within the scope of the present disclosure. Oil admission valve <NUM>, namely valve member <NUM> in the illustrated embodiment, includes an outer peripheral surface <NUM> extending around valve axis of reciprocation <NUM> and exposed to spray jet gallery <NUM> at the closed position. Outer peripheral surface <NUM> can thus be understood to form a wetted surface of forward segment <NUM> of spray jet gallery <NUM> and a wetted surface of back segment <NUM> of spray jet gallery <NUM>, when oil admission valve <NUM> is at the closed position. Oil admission valve <NUM>, namely valve member <NUM> in the illustrated embodiment, may also include an inner peripheral surface <NUM>. Inner peripheral surface <NUM> may also extend around valve axis of reciprocation <NUM> and forms a spring pocket <NUM> receiving spring biaser <NUM>. Each of outer peripheral surface <NUM> and inner peripheral surface <NUM> may be cylindrical giving valve member <NUM> a shape akin to a bucket or pail. Oil admission valve <NUM> may form a valve assembly of valve member <NUM>, spring biaser <NUM>, and a cap <NUM>. Cap <NUM> may be engaged with cylinder block casting <NUM>, within cast-in valve body <NUM>. In particular, cap <NUM> may be attached to valve boss <NUM> within valve bore <NUM> and engaged by way of threads <NUM>. Threads <NUM> can include external threads, with valve bore <NUM> suitably internally threaded. Cap <NUM> is received partially within recess <NUM>. Tool engagement surfaces <NUM>, for example a conventional female or male socket hex or the like, may be formed on or in cap <NUM>.

Referring now to <FIG>, there is shown cylinder block casting <NUM> equipped with an electrical actuator <NUM>. It will be appreciated that cylinder block casting is structured for use with either of the oil admission valve configurations and actuation principles discussed herein. Electrical actuator <NUM> may be attached to valve boss <NUM> and coupled to an oil admission valve member <NUM>. Oil admission valve member <NUM> could be similar or identical to admission valve member <NUM> or could have a different configuration. Electrical actuator <NUM> includes an armature <NUM> coupled to valve member <NUM>, a solenoid <NUM>, and an electrical plug or connector <NUM>, for communicatively connecting to an engine control system. Electrical actuator <NUM> is structured to move oil admission valve/valve member <NUM> from a closed position to an open position, in a manner functionally analogous to the embodiment described above. In one example, valve member <NUM> is biased closed with a spring biaser, and electrical actuator <NUM> is energized to move valve member <NUM> from a closed position in opposition to a biasing force of the spring biaser. In another implementation electrical actuator <NUM> moves valve member <NUM> between stop positions without the assistance of a spring biaser, or valve member <NUM> could be biased open and electrically actuated to close. It should be appreciated that the present disclosure is not limited with respect to valve configuration or valve operation, contemplating embodiments where an oil admission valve is purely passive, embodiments where an oil admission valve is actuated electrically, or combinations of these strategies.

Referring to the drawings generally, it will be recalled that engine <NUM> will be equipped with an oil pump. Embodiments are contemplated where a fixed displacement oil pump is employed and operated linearly with engine speed. At a relatively lower engine speed, an outlet pressure of the oil pump will act upon opening hydraulic surface <NUM>, with the outlet oil pressure being conveyed to opening hydraulic surface <NUM> through main oil gallery <NUM> and cross-hole <NUM>. At a relatively lower engine speed, however, the oil pressure may not be sufficient to overcome a biasing force of spring biaser <NUM>. As such, spray jet gallery <NUM> will not be fluidly connected to cross-hole <NUM>, and oil will not spray from oil spray jets <NUM>. When engine speed increases sufficiently, however, an oil pressure acting on opening hydraulic surface <NUM> will increase to a pressure sufficient to overcome a biasing force of spring biaser <NUM>, and fluidly connect cross-hole <NUM> to spray jet gallery <NUM> resulting in initiation of a spraying of oil with oil spray jets <NUM>.

In another embodiment, engine <NUM> is equipped with an oil pump that can vary its outlet pressure, for example, an inlet metered oil pump, an outlet metered oil pump, or an oil pump otherwise operated to vary an oil outlet pressure. Using an oil pump that varies its outlet pressure independently of engine speed, the oil pump can be operated as desired to increase or decrease oil pressure and thereby control spraying of oil with oil spray jets <NUM> by hydraulically controlling the opening or closing of an oil admission valve.

Claim 1:
A cylinder block (<NUM>) having formed therein a plurality of cylinders (<NUM>) extending between a top deck surface (<NUM>) and a bottom block surface (<NUM>), and arranged between a front block end (<NUM>), and a back block end (<NUM>);
the cylinder block (<NUM>) further having formed therein a main oil gallery (<NUM>) extending longitudinally between the front block end (<NUM>) and the back block end (<NUM>), a spray jet gallery (<NUM>), a plurality of oil feed holes (<NUM>) fluidly connected to the spray jet gallery (<NUM>), and a cross-hole (<NUM>) fluidly connected to the main oil gallery (<NUM>) and extending to the spray jet gallery (<NUM>);
a plurality of oil spray jets (<NUM>) each fluidly connected to one of the plurality of oil feed holes (<NUM>) and oriented to spray oil upwardly into one of the plurality of cylinders (<NUM>); and
an oil admission valve (<NUM>) supported in the cylinder block (<NUM>) and movable between a closed position where the oil admission valve (<NUM>) blocks the spray jet gallery (<NUM>) and each of the plurality of oil feed holes (<NUM>) from the cross-hole (<NUM>), and an open position;
characterised in that the spray jet gallery (<NUM>) includes a forward segment (<NUM>) arranged to feed oil to a forward set of the oil feed holes (<NUM>) and a back segment (<NUM>) arranged to feed oil to a back set of the oil feed holes (<NUM>); and
the oil admission valve (<NUM>) includes a three-way valve positioned fluidly between the forward segment (<NUM>) and the back segment (<NUM>) of the spray jet gallery (<NUM>).