CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Pat. App. No. 62/416,495, filed November 2, 2016, U.S. Provisional Pat. App. No. 62/492,576, filed May 1 , 2017, U.S. Provisional Pat. App. No. 62/520, 198, filed June 15, 2017, and U.S. Provisional Pat. App. No. 62/580,266, filed November 1 , 2017, the contents of which are incorporated herein by reference thereto.

FIELD

[0002] The present disclosure relates generally to valve actuation systems of internal combustion engines and more particularly to a cam-camless cylinder head and associated systems and operations.

BACKGROUND

[0003] Internal combustion engines have a cylinder head mounted to an engine block that at least partially forms a plurality of cylinder combustion chambers. The cylinder head has multiple intake ports and multiple exhaust ports. Valves regulate the passage of gas into and out of the combustion chamber.

[0004] Cam operated valves are mechanically coupled to a rotating cam directly or through one or more of a variety of components that assist in transforming the rotational kinetic energy of the cam to linear motion of the valves. One of the exhaust valves and one of the intake valves are mechanically coupled to the cam. Electrohydraulic actuators actuate separate intake and exhaust valves of a particular cylinder as part of a camless system. The electrohydraulic actuators are in fluid communication with a high pressure fluid source.

[0005] Traditionally, camless systems have used externally mounted (outside of the valve train actuation system) hydraulic pumps to power the pressure rail that feeds the hydraulic actuators. This generally is due to the lack of any mechanical driven hardware that could drive a pump located in the vicinity of the camless hydraulic actuators. [0006] The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

SUMMARY

[0007] In one aspect, an engine valve actuation system for an internal combustion engine that includes a cylinder head mounted to a cylinder block to form at least one combustion chamber is provided. The engine valve actuation system includes a first valve movable between an opened position and a closed position to selectively open a first port on the cylinder head, a second valve movable between an opened position and a closed position to selectively open a second port on the cylinder head, a rocker arm that moves based on rotation of a cam, and wherein one of the first and second valves is actuated mechanically by the rocker arm and the other of the first and second valves is actuated by a hydraulic pressure supply system. The hydraulic pressure supply system includes at least one pump configured to deliver a hydraulic fluid to a hydraulic actuator that actuates the hydraulically actuated valve.

[0008] In addition to the foregoing, the described engine valve actuation system may include one or more of the following features: wherein the first valve is an intake valve and the second valve is an exhaust valve; wherein the first valve is an exhaust valve and the second valve is an intake valve; wherein the at least one pump comprises a first, second and third pump; a pressure rail that communicates hydraulic fluid from the at least one pump to the hydraulic actuator; a pressure regulation valve that controls hydraulic fluid exiting from the pressure rail; a hydraulic fluid reservoir that delivers hydraulic fluid to the at least one pump by way of a fluid supply line; and a fluid return line that routes hydraulic fluid from the pressure rail, through the pressure regulation valve and back to the fluid reservoir.

[0009] In addition to the foregoing, the described engine valve actuation system may include one or more of the following features: wherein the at least one pump is a piston pump having a pump body that slidably receives a plunger that is translated along a pumping chamber as a result of cam motion; wherein the pump body further defines a pump inlet that receives hydraulic fluid from the fluid reservoir and a pump outlet that delivers hydraulic fluid to the pressure rail; wherein the pump body further comprises an outlet check valve positioned between the pumping chamber and the pump outlet; and wherein the at least one pump is driven by the cam or is electrically driven.

[0010] In addition to the foregoing, the described engine valve actuation system may include one or more of the following features: wherein the pump includes a flow control valve assembly that controls the volume of hydraulic fluid pumped by the pump; wherein the flow control valve assembly includes an armature rod connected to a control valve plate that is normally biased toward a closed position by a biasing member; wherein the valve assembly includes a solenoid that is electronically controlled by an engine control unit (ECU) to regulate rail pressure; and wherein the ECU is programmable to provide at least two variable valve actuation (WA) configurations to alter a valve train profile.

[0011] In addition to the foregoing, the described engine valve actuation system may include one or more of the following features: wherein the at least two WA configurations include at least two of: early exhaust valve closing (EEVC), late exhaust valve closing (LEVC), early exhaust valve opening (EEVO), late exhaust valve opening (LEVO), early intake valve closing (EIVC), late intake valve closing (LIVC), early intake valve opening, late intake valve opening, swirl, cylinder deactivation, internal exhaust gas recirculation (EGR), four stroke braking, two stroke braking and variable stroke braking; wherein the ECU receives a signal from a vehicle global positioning system (GPS) having a WA configuration of the WA configurations; wherein the ECU determines a most efficient WA profile based on a vehicle's location identified by the GPS; and wherein a WA configuration is provided based on at least one of vehicle route, traffic pattern, ozone action day, fuel economy and grade change.

[0012] In addition to the foregoing, the described engine valve actuation system may include one or more of the following features: wherein the internal combustion engine is a gasoline engine; wherein the internal combustion engine is a dual fuel engine; wherein the internal combustion engine is a diesel engine; wherein the internal combustion engine is a natural gas engine; wherein the rocker arm is configured for cylinder deactivation; and wherein the cylinder head is a self-contained cylinder head comprising all of the first valve, second valve, and rocker arm and having a self- contained hydraulic fluid supply.

[0013] In addition to the foregoing, the described engine valve actuation system may include one or more of the following features: wherein the at least one pump is an array of pumps; wherein the pumps are arranged linearly; wherein the pump array includes a housing defining a plurality of cavities, each cavity configured to receive one pump; wherein the housing includes an upper housing and a lower housing; wherein the housing defines a space, the space receiving a camshaft having a plurality of cams each configured to selectively engage one pump; a biasing mechanism disposed between each pump and the housing, the biasing mechanism configured to bias the pump toward the camshaft; and wherein the biasing mechanism is a wave spring.

[0014] In another aspect, an engine valve actuation system for an internal combustion engine that includes a cylinder head is provided. The engine valve actuation system includes a first intake valve movable between an open position and a closed position to selectively open and close a first intake port of the engine, a first exhaust valve movable between an open position and a closed position to selectively open and close a first exhaust port of the engine, a second valve movable between an open position and a closed position to selectively open and close a second port of the engine, a rotating cam mechanically coupled to the first intake valve and the first exhaust valve, the rotating cam selectively actuating the first intake valve and the first exhaust valve between the respective open and closed positions, and a hydraulic valve actuator coupled to the second valve to selectively actuate the second valve between the open and closed positions. The hydraulic valve actuator is supported by an actuator retention member coupled to the cylinder head.

[0015] In addition to the foregoing, the described engine valve actuation system may include one or more of the following features: wherein the actuator retention member is disposed between a valve spring and the cylinder head; and a feed rail fluidly coupled to the hydraulic valve actuator, wherein the actuator retention member is coupled between the feed rail and the engine head.

[0016] In another aspect, a hydraulic actuator configured to selectively actuate a valve of an internal combustion engine between an open position and a closed position is provided. The hydraulic actuator includes an actuator housing defining a piston cavity, a piston cavity inlet port, a high pressure inlet, and a low pressure port. A two- stage piston is disposed at least partially within the piston cavity and having a small diameter piston slidably disposed within a piston bore of a large diameter piston, the two-stage piston having an upper surface formed by both the small and large diameter pistons. An actuator valve is disposed within the actuator housing and in fluid communication with the inlet port, the high pressure port, the low pressure port and a volume defined by the actuator housing and the two-stage piston upper surface. An aperture extends transversely through the small diameter piston proximate the upper surface.

[0017] In addition to the foregoing, the described hydraulic actuator may include one or more of the following features: a tubular member disposed within the transversely extending aperture; wherein the small diameter piston includes a cap disposed on an end of an insert; wherein the actuator housing defines an inner shoulder configured to prevent further movement of the large diameter piston in one direction; wherein the actuator housing defines a second inner shoulder configured to prevent further movement of the large diameter piston in one direction; wherein the actuator housing defines at least one fastener aperture configured to receive a fastener for coupling the actuator housing to a hydraulic fluid feed rail; and wherein the large diameter piston is disposed directly adjacent an inner surface of the actuator housing.

[0018] In another aspect, an engine valve assembly for an internal combustion engine is provided. The assembly includes an outer valve and an inner valve slidably disposed within the outer valve. When a force is applied to a top of the inner and outer valves, the inner valve is configured to open before the outer valve to relieve pressure in a combustion chamber of the engine.

[0019] In addition to the foregoing, the described engine valve assembly may include one or more of the following features: at least one port formed in the outer valve; a spring keeper coupled to the outer valve; a biasing mechanism configured to be disposed between the spring keeper and a portion of the engine, the biasing mechanism configured to bias the outer valve into a closed position; wherein the biasing mechanism is a coil spring; a second biasing mechanism disposed between the outer valve and the inner valve, the second biasing mechanism configured to bias the inner valve into a closed position; wherein the second biasing mechanism is a coil spring; and wherein the outer valve includes a bore formed therein, the second biasing mechanism disposed at least partially within the bore.

[0020] In another aspect, an engine valve actuation system for an internal combustion engine that includes a cylinder head mounted to a cylinder block to form at least one combustion chamber is provided. The engine valve actuation system includes a first valve movable between an opened position and a closed position to selectively open a first port on the cylinder head, a second valve movable between an opened position and a closed position to selectively open a second port on the cylinder head, a rocker arm that moves based on rotation of a cam, and wherein one of the first and second valves is actuated mechanically by the rocker arm and the other of the first and second valves is actuated by a high pressure fuel supply for the internal combustion engine.

[0021] In addition to the foregoing, the described engine valve actuation system may include one or more of the following features: a hydraulic pressure supply system configured to deliver a hydraulic fluid to a hydraulic actuator that actuates the other of the first and second valves, wherein the hydraulic fluid is at least partially pressurized by the high pressure fuel supply; a pressure intensifier disposed between the high pressure fuel supply and the hydraulic fluid and configured to transfer pressure therebetween; and a pressure reducer disposed between the high pressure fuel supply and the hydraulic fluid and configured to transfer pressure therebetween.

[0022] In another aspect, a method of reducing lift on a valvetrain having mechanically actuated engine valves and hydraulically actuated engine valves is provided. The method includes determining a lift profile for the mechanically actuated engine valves, determining a point on the lift profile where each port of the valvetrain is choked, determining which port of the valvetrain will choke first, and coupling a hydraulic actuator to an engine valve associated with the port that will choke first.

[0023] In addition to the foregoing, the described method may include one or more of the following features: lowering a lift of the engine valve associated with the port that will choke first, the lift being at a point on the lift profile below the choke point; operating the hydraulic actuator such that the engine valve associated with the port that will choke first will have a steeper lift profile such that the engine valve will open and close faster than the mechanically actuated engine valves while providing at least equivalent flow; operating the hydraulic actuator such that the lift profile of the engine valve associated with the port that will choke first includes a plateau between the opening and closing of the lift profile; and providing a proud-style engine valve for the engine valve associated with the port that will choke first. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0025] FIG. 1 is a partially exploded perspective view of a cylinder head constructed in accordance to one prior art example;

[0026] FIG. 2 is a sectional view taken along line 2-2 of the cylinder head of FIG. 1.

[0027] FIG. 3 is a schematic illustration of a cam-camless engine provided by a cam-driven high pressure oil pump according to one example of the present disclosure;

[0028] FIG. 4 is a sectional view of a piston pump of the cam-camless engine of FIG. 3 according to one example of the present disclosure;

[0029] FIG. 5 is a sectional view of a piston pump that provides additional flow control and reduces power consumption, the piston pump constructed in accordance to another example of the present disclosure;

[0030] FIG. 6 illustrates various oil pressures of the flow control valve of the present disclosure;

[0031] FIG. 7 is a cross-sectional view of an array of piston pumps for a cam- camless engine according to one example of the present disclosure;

[0032] FIG. 8 is another cross-sectional view of the array of piston pumps shown in FIG. 7;

[0033] FIG. 9 is a partial sectional view of a valve train configuration having a pumping system that is actuated by a rocker arm instead of a camshaft according to another example of the present disclosure;

[0034] FIG. 10 illustrates various cam-camless profiles that may be provided with a cylinder head of the present disclosure;

[0035] FIG. 1 1 is an illustration of a deactivation rocker arm that may be used in conjunction with the cam-camless valve train system;

[0036] FIG. 12 is a perspective view of a partial cylinder head according to one example of the present disclosure;

[0037] FIG. 13 is a sectional view of a cylinder head according to another example of the present disclosure;

[0038] FIG. 14 is a sectional view of a cylinder head according to yet another example of the present disclosure; [0039] FIG. 15 is a perspective view of a cylinder head according to yet another example of the present disclosure;

[0040] FIG. 16 is a perspective view of a portion of the cylinder head shown in FIGS. 12-15;

[0041] FIG. 17 is perspective view of an example hydraulic actuator that may be used with the cylinder heads shown in FIGS. 12-16, according to one example of the present disclosure;

[0042] FIG. 18 is a side view of the hydraulic actuator shown in FIG. 17;

[0043] FIG. 19 is a cross-sectional view of the hydraulic actuator shown in FIG. 17 taken along line 19-19;

[0044] FIG. 20 is a cross-sectional view of the hydraulic actuator shown in FIG. 18 taken along line 20-20;

[0045] FIG. 21 is a cross-sectional view of an engine valve according to one example of the present disclosure;

[0046] FIG. 22 is a cross-sectional view of a two-stage nested engine valve assembly, in a first position, according to one example of the present disclosure;

[0047] FIG. 23 is a cross-sectional view of the nested engine valve assembly shown in FIG. 22 is a second position;

[0048] FIG. 24 is a cross-sectional view of the nested engine valve assembly shown in FIG. 22 in a third position;

[0049] FIG. 25 is a cross-sectional view of another two-stage nested engine valve assembly, in a first position, according to one example of the present disclosure;

[0050] FIG. 26 is a cross-sectional view of the nested engine valve assembly shown in FIG. 25 in a second position;

[0051] FIG. 27 is a cross-sectional view of the nested engine valve assembly shown in FIG. 25 in a third position;

[0052] FIG. 28 is a graph illustrating an engine valve lift profile according to one example of the present disclosure;

[0053] FIG. 29 is a graph illustrating an engine valve lift profile according to one example of the present disclosure; and

[0054] FIG. 30 is a graph illustrating an engine valve lift profile according to one example of the present disclosure.

DETAILED DESCRIPTION [0055] In a cam-camless valve train system, a camshaft and rocker arms, and in some cases push rods, are arranged to open up a set of valves mechanically. Since these mechanically moving components (camshaft, rocker arms, and in some cases pushrods) are present in the vicinity of the cam-camless hydraulic actuators, these components could be used to power the pumping mechanism that supplies hydraulic pressure for actuation of the cam-camless hydraulic actuators. The present teachings incorporate a piston pump within the cam-camless actuation assembly. The present disclosure represents a reduction in components, shorter hydraulic pumping paths, a lower cost solution due to the reduction in components, and the potential for implementing a self-contained cylinder head where alternate oils and long lasting oils can be used to extend, or possibly eliminate oil changes.

[0056] With initial reference to FIG. 1 , a cylinder head constructed in accordance to one prior art example is shown and generally identified at reference 100. Additional description may be found in commonly owned U.S. Patent No. 9, 157,339, the contents of which are expressly incorporated herein by reference. The cylinder head 100 is configured to be mounted on an engine block of a diesel engine (not shown). However, the same may be applicable to other types of internal combustion engines such as those consuming gasoline, biofuels or other fuels. An engine block on which the cylinder head 100 can be mounted can contain piston bores, and pistons can be inserted into such bores to form combustion chambers (not shown). The cylinder head 100 can form the top portion of the combustion chambers when mounted on the engine block.

[0057] The cylinder head 100 is for use with cylinders of an inline six cylinder engine. However the teachings may be applicable to other engine configurations as well, such as straight engine configurations, and a different number of cylinders more or less than twelve. For example, the present teachings are applicable to engines having six, eight and ten cylinders.

[0058] The cylinder head 100 shown in FIG. 1 includes a hybrid valve actuation system wherein both mechanical and electrohydraulic actuation mechanisms are used to open and close engine valves of a particular cylinder. When mounted on an engine block, the cylinder head 100 forms part of six combustion chambers. The head 100 includes twenty-four engine valves in total, four for each of the combustion chambers partially formed by the cylinder head. A feed rail 101 can be mounted at the top of the cylinder head 100, and includes two high pressure conduits 103 that supply high pressure hydraulic fluid to electrohydraulic actuators 104. A low pressure drain conduit 105 allows hydraulic fluid to flow from the electrohydraulic actuators 104.

[0059] As shown in FIG. 2, two engine valves 102 corresponding to one of the cylinders are actuated by an electrohydraulic actuator 104. The other two engine valves 102 of the cylinder are mechanically actuated by a cam 1 12 and rocker arms 1 14. It is contemplated that in some configurations using engine braking, only one of the valves 102 (per cylinder) associated with the exhaust is actuated by an electrohydraulic actuator 104. Alternatively, only one of the valves 102 (per cylinder) associated with the intake is actuated by an electrohydraulic actuator 104. The cylinder head 100 includes intake ports 106 and exhaust ports 108 through which air enters and combusted gas leaves the combustion chamber, respectively, during engine operation.

[0060] The engine valves 102 actuated by electrohydraulic actuators 104 open and close respective passages from the combustion chamber to intake and exhaust ports 106, 108. Thus, one of the intake ports 106 for a particular cylinder is regulated by one of the electrohydraulic actuators 104, and one of the exhaust ports 108 is also regulated by one of the electrohydraulic actuators 104. For a particular cylinder, the entry and exit of gas from the combustion chamber is regulated in part by the valves 102 that are actuated mechanically, and in part by valves 102 actuated by electrohydraulic actuators 104. When closed, the engine valves 102 are seated against valve seats 1 10. Mechanical actuation of engine valves 102 is achieved by the rotating cam 1 12, which periodically transfers motion to rocker arm 1 14, which in turn transfers linear motion to the engine valves 102.

[0061] Turning now to FIG. 3, a cylinder head 200 constructed in accordance to one example of the present disclosure is shown and generally includes a hydraulic pressure supply system 202. The cylinder head 200 can have a hybrid valve actuation system wherein both mechanical and electrohydraulic actuation mechanisms are used to open and close the engine valves of a particular cylinder. As will also be discussed herein, the present disclosure provides a programmable variable valve assembly with a cam-camless configuration. In some examples, programmable levels of engine braking can be included such as actuation closer to top dead center (TDC) for more power and more noise, or further away from TDC for less power and less noise. It is appreciated that the same may be used for two or four stroke braking. [0062] The hydraulic pressure supply system 202 incorporates cam-driven high pressure oil pumps, collectively referred to at reference 210 that provide the oil rail pressure into a common rail 212. Alternatively, one or more of the pumps described herein may be electrically actuated, for example by a solenoid. It is appreciated that the common rail 212 may take the place of the feed rail 101 (FIG. 1 ). In the example shown, the cam-driven high pressure oil pumps 210 include oil pumps 210a, 210b and 210c. In a typical design, the volume of oil pumped is constant and the power can be reduced by controlling the pressure in the supply rail. A pressure regulation valve 220 is provided in the cam-camless pressure rail 212 and controls oil exiting therefrom.

[0063] In one example, all of the components shown in FIG. 1 can be located in the cylinder head assembly. Explained further, the features on FIG. 1 can be provide in a self-contained cylinder head without requiring oil connection to other engine system components. This would provide the opportunity to optimize the oil for the valve train system. The oil pumps 210 can be driven off a camshaft having multiple lobes (for example, as shown in FIGS. 7 and 8). The number of lobes is dependent on maximum engine speed pump piston displacement and flow demand. A typical camshaft will have three to six lobes per camshaft revolution to stroke the pumps 210 and provide the required flow to actuate hydraulic actuators 222.

[0064] With continued reference to FIG. 3, the oil pumps 210 receive oil from an oil reservoir 228 that delivers oil to the oil pumps 210 by way of an oil supply line 230. A low pressure pump 232 can deliver the oil into the oil supply line 230, and a filter 240 can be configured in-line with the oil supply line 230. Oil delivery lines, collectively identified at reference 244, route oil from the oil pumps 210 into the common rail 212, and a pressure sensor 248 can be coupled to the common rail 212 for sensing a rail pressure thereat. An oil return line 250 can route oil from the common rail 212, through the pressure regulation valve 220, and back to the oil reservoir 228. Return lines (not particularly shown) may also be provided from the actuators 222 to the oil reservoir 228.

[0065] With particular reference to FIG. 4, a piston pump 210a constructed in accordance to one example of the present disclosure will be described. It will be appreciated that the other piston pumps 210b and 210c may be constructed similarly. The piston pump 210a includes a pump body 260 slidably receiving a plunger 262 that is translated along a pumping chamber 266 as a result of cam motion. The pump body 260 further defines a pump inlet 270 and a pump outlet 272. The pump inlet 270 receives oil from the oil supply line 230, and the pump outlet 272 sends pumped oil through the oil delivery lines 244 to the common rail 212. An inlet check valve 280 can be positioned between the pump inlet 270 and the pumping chamber 266, and an outlet check valve 282 can be positioned between the pumping chamber 266 and the pump outlet 272. In some examples, the pump 210 can be configured to provide gasoline to a gas direct injection (GDI) system as well as the valve actuation system.

[0066] Turning now to FIG. 5, a cam-driven variable stroke high pressure oil pump 310 constructed in accordance to another example of the present disclosure is shown. It will be appreciated that the oil pump 310 is an alternative to the pump 210. In some examples, one oil pump 310 may be provided in place of oil pump 210a in the same system with oil pumps 210b and 210c giving greater flexibility. The high pressure oil pump 310 includes a pump body 312 defining a pump inlet 314, a pump outlet 316, and a pumping chamber 320. A plunger 330 is translated along the pumping chamber 320 as a result of cam motion. The cam-driven variable stroke high pressure oil pump 310 can alternatively be used in the hydraulic pressure supply system 202 described above. The high pressure oil pump 310 provides oil rail pressure with additional flow control and reduced power consumption, and includes a flow control valve assembly 340 located at the pump inlet 314.

[0067] The pressure and volume of oil pumped by the high pressure oil pump 310 is controlled by the flow control valve assembly 340, which can be electronically controlled by an engine control unit (ECU) 336. Similar function and control may be used for oil pumps 210. The flow control valve assembly 340 can include an armature rod 342 connected to a control valve plate 344 that can be normally biased toward a closed position by a biasing member 346. The valve assembly 340 includes a solenoid 348 electronically controlled by the ECU 336 to regulate oil rail pressure. As such, the oil pressure can be regulated by controlling the flow control valve assembly 340 during the stroke of the pump 310 to regulate how much of the stroke is allowed to draw oil into the pumping chamber 320. The high pressure oil pump 310 can include an outlet check valve 350 and a relief path 352 having a pressure relief valve 354.

[0068] With additional reference to FIG. 6, operation of the high pressure oil pump 310 will be described. Oil enters the pumping chamber 320 during downward motion of the plunger 330 through the open control valve assembly 340. The control valve assembly 340 opens during this time due to the valve being held open by the spring and the suction of the control valve plate (piston) 344. This results in a lower pressure in the pumping chamber 320 as compared to the oil inlet 314 and oil flows into the pumping chamber 320. If the solenoid 348 remains de-energized during the upward stroke of the cam and plunger 330, the valve stays open due to the spring force, preventing the pump 310 from developing pressure.

[0069] The oil pump 310 thus delivers no oil to the oil rail 212. If the solenoid 348 is energized during the upward stroke, the control valve assembly 340 closes and the low pressure inlet 314 is sealed off from the pumping chamber 320. This allows high pressure to be developed in the pumping chamber 320. Once enough pressure has been developed, the outlet check valve 350 opens and pressurized oil is delivered to the oil rail 212. The quantity of oil delivered by the oil pump 310 can be adjusted by controlling the exact moment in the upward plunger stroke that the solenoid 348 is energized. The earlier the valve closes, the higher the quantity of oil delivered to the oil rail 212. The earlier the coil is energized, the earlier the valve closes and the higher the quantity of oil that can be delivered to the rail 212.

[0070] The relief path 352 using the pressure relief valve 354 is provided to prevent over-pressurization of the oil rail 212, however, this relief path 352 is not normally used for oil pressure control. The relief pressure setting is set higher than the maximum pressure expected during normal engine operation. Operating the relief valve 354 in this manner results in higher engine efficiency through reduced oil pump drive losses. For example, during periods of time when actuation of the hydraulic valves is not required, no oil will flow out of the oil rail 212 because the hydraulic actuators are disabled. In such a case, the solenoid 348 can be left de-energized and the rail pressure will remain at its previous set point without the oil pumps 310 adding any additional oil, thus saving pumping work.

[0071] Turning now to FIGS. 7 and 8, an array 400 of piston pumps 402 constructed in accordance to one example of the present disclosure is shown. The piston pump array 400 may be utilized with a hydraulic pressure supply system (e.g., 202) of a cylinder head (e.g., 200). In the example embodiment, the piston pumps 402 are arranged linearly and have outputs synchronized with the power consumption events of the cam-camless actuators. The array 400 generally includes an upper housing 404 and a lower housing 406, which can be coupled to the cylinder head. A first space or cavity 408 is defined by the upper and lower housings 404, 406 and is configured to receive a camshaft 410 for rotation therein. A plurality of cams 412 are disposed on the camshaft 410 and include one or more lobes 414 (FIG. 8) for selectively actuating the piston pumps 402.

[0072] The upper housing 404 defines a plurality of second spaces or cavities 416 each configured to receive one piston pump 402. As illustrated, each piston pump 402 includes a main body 420 that includes a seal 422 and a roller 424. The seal 422 is configured to seal against the upper housing 404, and the roller 424 is rotatably mounted within the main body 420. The roller 424 is disposed for engagement with one cam 412. A biasing member 426 (e.g. , a wave spring) is disposed between the main body 420 and the upper housing 404, and is configured to bias the roller 424 toward the cam 412. During operation, the camshaft 410 rotates the cams 412 such that lobes 414 engage rollers 424 and push the main bodies 420 upward (as shown in FIG. 7). After further rotation, biasing members 426 force the main bodies 420 back downward towards the camshaft 410. As such, the upward and downward translation of the main bodies 420 within the second cavities 416 creates a pumping force.

[0073] Turning now to FIG. 9, a cylinder head 500 constructed in accordance to another example of the present disclosure is shown and generally includes a hydraulic pressure supply system 502. The hydraulic pressure supply system 502 is actuated by a rocker arm 510 instead of a camshaft. The rocker arm 510 provides motion to a plunger 512 movable within a chamber 514 to pressurize a high pressure rail 520 similar to described above with the common rail 212. The layout can be similar as shown in FIG. 3 above and/or the configuration of pump 310. However, it will be appreciated that the number of pumps can vary depending on the flow demands, loading of the rocker arm and the pump piston size. In this regard, the configuration can include only a few piston pumps or one for each rocker arm.

[0074] Turning now to FIGS. 5, 10, and 1 1 , additional features of the present disclosure will be described. The flow control valve assembly 340 is electronically controlled by ECU 336 (FIG.5) to regulate oil rail pressure. In one configuration, the ECU 336 is programmable to ultimately provide distinct WA profiles. In one implementation a vehicle global positioning (GPS) system 380 can communicate with a satellite 382. The GPS system 380 can communicate with the satellite 382 (it is appreciated that while one satellite 382 is shown, the GPS system 380 can communicate simultaneously with one or more satellites) to determine a vehicle's location (latitude and longitude) as well as elevation. Based on a vehicles location, the ECU 336 can determine the most efficient WA profile. For example it may be desirable to operate along a distinct WA profile for city driving compared to rural transit. By way of example only, the ECU 336 can be configured to run cylinder deactivation and/or early intake valve closing (ElVC) while in a downtown urban area. Likewise, the ECU 336 can be configured to run late intake valve closing (LIVC) in rural areas. Similarly, the ECU 336 can be configured to run an optimized WA profile based on vehicle route, traffic pattern, ozone action day, fuel economy, elevation changes and other factors. It is contemplated that a customer and/or equipment provider can communicate with the ECU 336 to modify valve operating conditions upon various service intervals or even real time.

[0075] FIG. 10 illustrates various cam-camless profiles that may be provided with the cylinder head 200 of the present disclosure. In particular, similar hardware can be provided for achieving distinct WA profiles including early exhaust valve closing (EEVC), late exhaust valve closing (LEVC), early exhaust valve opening (EEVO), late exhaust valve opening (LEVO), early intake valve closing (ElVC), late intake valve closing (LIVC), early intake valve opening (EIVO), late intake valve opening (LIVO), swirl, cylinder deactivation, internal exhaust gas recirculation (EGR), four stroke braking, two stroke braking and variable stroke braking.

[0076] FIG. 1 1 illustrates a cam-camless layout for use with cylinder deactivation. For cylinder deactivation, the use of deactivation rocker arms 614 may be used on three of the cylinders in addition to the camless valves. Deactivation can be achieved by not activating the camless valves and deactivating the mechanical rocker arms on three cylinders.

[0077] Turning now to FIG. 12, an example cylinder head 700 constructed in accordance to one example is illustrated. FIG. 13 illustrates cylinder head 700 with a first structural configuration to support valve actuators, and FIG. 14 illustrates cylinder head 700 with a second structural configuration to support valve actuators, as described herein in more detail.

[0078] Cylinder head 700 is configured to be mounted on an engine block of a diesel engine. However, the present teachings are not limited to diesel engines, and are applicable to other types of internal combustion engines such as those consuming gasoline, biofuels, or other fuels. An engine block on which the cylinder head 700 can be mounted can contain piston bores to form combustion chambers. The cylinder head 700 can form the top portion of the combustion chambers when mounted on the engine block. [0079] The illustrated cylinder head 700 is for use with a six cylinder engine. However, the present teachings are applicable to other engine configurations as well, such as straight engine configurations, and different numbers of cylinders more or less than six. For example, the present teachings are applicable to engines having eight, ten, and twelve cylinders.

[0080] The cylinder head 700 shown in FIG. 12 includes a hybrid valve actuation system wherein both mechanical and electrohydraulic actuation mechanisms are used to open and close engine valves 702 of a particular cylinder. When mounted on an engine block, the cylinder head 700 forms part of six combustion chambers. The cylinder head 700 includes twenty-four engine valves in total, four for each of the combustion chambers partially formed by the cylinder head. A feed rail 704 (FIGS. 13 and 14) can be mounted at the top of cylinder head 700. The feed rail 704 has two high pressure conduits 706 that supply high pressure hydraulic fluid to electrohydraulic actuators 708 discussed further herein, and a low pressure drain conduit 710 that allows hydraulic fluid to flow from the electrohydraulic actuators 708.

[0081] FIGS. 13 and 14 illustrate sectional views of the cylinder head 700 shown in FIG. 1 1. However, FIG. 13 illustrates cylinder head 700 with first structural configuration having actuator retention members 712 at the base of springs 714, and FIG. 14 illustrates cylinder head 700 with a second structural configuration having one or more actuator retention members 716 at the top of the actuators 708.

[0082] As shown in FIG. 14, each actuator retention member 716 includes an upper connection flange 730, a lower connection flange 732, and a pair of support arms 734 extending therebetween. The upper connection flange 730 is coupled to an upper surface of a shoulder 736 of the feed rail 704 by a plurality of fasteners 738. The lower connection flange 732 can be coupled to the engine block by a fastener 740. As illustrated, the upper and lower connection flanges 730, 732 and the support arms 734 can have an outwardly extending web or lip 742 to increase the strength thereof. FIG. 15 illustrates another alternative structural configuration for actuator retention members 716 that is similar to the embodiment shown in FIG. 14 except it includes a wider web 744 that increases in width as it extends from the upper connection flange 730 to the lower connection flange 732.

[0083] In the illustrated examples, two of the engine valves 702 corresponding to one of the cylinders are actuated by electrohydraulic actuators 708. The other two engine valves 702 are mechanically actuated by a cam 718 and rocker arms 720. As shown in FIG. 16, the electrohydraulic actuators 708 can be coupled to a lower surface 750 of the feed rail 704 by a plurality of fasteners 752.

[0084] The cylinder head 700 includes intake and exhaust ports 722, 724 through which air enters and combusted gas leaves the combustion chamber, respectively, during engine operation. The engine valves 702 actuated by electrohydraulic actuators 708 open and close respective passages from the combustion chamber to intake and exhaust ports 722, 724. Thus, one of the intake ports 722 for a particular cylinder is regulated by one of the electrohydraulic actuators 708 and one of the exhaust ports 724 is also regulated by one of the electrohydraulic actuators 708. For a particular cylinder, the entry and exit of gas from the combustion chamber is regulated in part by the valves 702 that are actuated mechanically and in part by valves 702 actuated by electrohydraulic actuators 708. When closed, the engine valves 702 are seated against valve seats 726.

[0085] Mechanical actuation of engine valves 702 is achieved through the rotating cam 718 periodically transferring motion to rocker arm 720, which in turn transfers linear motion to engine valves 702. Such mechanical actuation illustrates one possible type of mechanical valve actuation according to the present disclosure. Other forms of mechanical actuation may also be implemented to transform the rotational motion of a cam to kinetic energy or mechanical potential energy, and ultimately to translational motion of engine valves 702. Such mechanisms include a rotating cam placed in direct contact with an engine valve 702, or by including one or both of a lash adjuster and rocker arm between a cam and engine valve. Still other combinations of various valve train components are possible in order to achieve mechanical actuation of an engine valve. Such components include but are not limited to rocker arms, including deactivating rocker arms and variable lift rocker arms, pushrods, hydraulic lash adjusters and tappets.

[0086] FIGS. 17-20 illustrate one example of electrohydraulic actuator 708 that may be used with cylinder head 700.

[0087] In the example embodiment, and with particular reference to FIG. 20, electrohydraulic actuator 708 generally includes a two stage hydraulic piston 802 having a large diameter piston member 804 partially disposed within a cavity 806 of an actuator housing 808. The large diameter piston member 804 has a cylindrically- shaped piston head 810 at one end 81 1 in fluid communication with hydraulic fluid that fills a volume 812. The volume 812 is formed in part by the housing 808, including the walls of the cavity 806, an upper surface 814 of the piston head 810 and an upper surface 816 of one end 817 of a small diameter piston 818. The piston head 810 has a cylindrical shape, and the cavity 806 has a size and shape that permits a close fit between the cavity 806 and piston 804, which in turn minimizes leaking of pressurized fluid from volume 812.

[0088] The small diameter piston member 818 includes a cap 880 disposed at end 817, and an insert 882. An aperture 884 is formed transversely through cap 880 and insert 882, and is configured to receive a tubular member 886. The insert 882 comes into contact with the engine valve 702, which contact causes the engine valve 702 to move in response to the motion of the piston 802. In other aspects of the present teachings, the insert 882 may be integrated into an engine valve 702.

[0089] The small diameter piston member 818 is disposed within a tubular piston bore 820 in the large diameter piston member 804. Portions of the piston bore 820 have a shape complementary to the small diameter piston member 818. This complementary shape limits the motion of the small diameter piston member 818 with respect to the large diameter piston member 804. The small diameter piston member 818 has a cylindrically shaped outer surface 822 distal to the volume 812 relative to a frustoconical outer surface 828 of the small diameter piston member 818. The large diameter piston member 804 has a cylindrically shaped inner surface 823 that has a shape complimentary to the cylindrically shaped outer surface 822, and a frustoconical inner surface 832 that has a shape complimentary to the frustoconical outer surface 828. The complementary shapes limit the motion of the small diameter piston member 818 toward the volume 812.

[0090] The small diameter piston member 818 has another cylindrically shaped outer surface 824 proximal to the volume 812 relative to the frustoconical outer surface 828 of the small diameter piston member 818. The large diameter piston member 804 also has another cylindrically shaped inner surface 830 that has a shape complimentary to the cylindrically shaped outer surface 824 proximal to volume 812. The bore 820 is narrower at a stop 826 than the diameter of the cylindrically shaped outer surface 824 of small diameter piston member 818. The stop 826 thus limits the downward motion of the small diameter piston member 804.

[0091] According to one aspect of the present teachings, the actuator housing 808 of the hydraulic actuator 708 includes a valve housing 834 and a piston guide 836 (see FIG. 19). In the illustrated actuator housing 808, the valve housing 834 is mounted above the piston guide 836. The piston 802 is partially inserted within the piston guide 836, which can be defined by one or more shoulders defined in an interior of the actuator housing 808.

[0092] In the illustrated example, the hydraulic actuator 708 includes a two position solenoid-based flow valve 838. The flow valve 838 includes a high pressure inlet 840, and low pressure outlets 842. The flow valve 838 also includes volume inlet ports 844 that permit fluid to enter the volume 812 from the high pressure inlet 840, or allow fluid to exit the volume 812 through the low pressure outlets 842. During operation, the high pressure inlet 840 is in fluid communication with the high pressure fluid source, such as a high pressure feed conduit 706 of the feed rail 704 described above, while the low pressure outlets 842 are in fluid communication with the low pressure reservoir, such as the low pressure drain conduit 710 of the feed rail 704.

[0093] An actuator valve, such as the illustrated spool valve member 846, regulates the flow of hydraulic fluid between the high pressure inlet 840, low pressure outlet 842, and volume inlet port 844. The spool valve member 846 includes a magnetic material that is responsive to magnetic fields generated by the coils 848 of a solenoid that can be activated to shift the position of the spool valve member 846. The spool valve member 846 controls whether pressurized fluid flows into volume 812, which in turn controls actuation of the engine valve 702 coupled to the piston 802.

[0094] In other embodiments, one or more camless actuators may be utilized lifting half that of cam base systems to reduce parasitics by operating with less valve lift to reduce energy consumption of the actuators. Moreover, one or more proud-style engine valves 900 (FIG. 21) may be utilized to reduce the lift of the camless actuators and maintain flow. In the illustrated example, each engine valve 900 is disposed within a cylinder head 902 and includes a stem 904 and a base 906. When in the closed position shown in FIG. 21 , a lower surface 908 of the base 906 is disposed away from or proud of a lower surface 910 of the cylinder head 902. Accordingly, in the valve closed position, lower surface 908 is disposed a distance 'D' from the cylinder head lower surface 910. Such valves 900 are configured to increase flow rate at low lifts.

[0095] In other embodiments shown in FIGS. 22-27, the systems described herein may include one or more two-stage nested engine valves 1000 in place of one or more engine valves 102. However, it will be appreciated that engine valve 1000 may be utilized in various other internal combustion engines. [0096] FIGS. 22-24 illustrate one embodiment of nested engine valve 1000 that includes an inner valve 1002 slidably disposed within an outer valve 1004. The outer valve 1004 can be slidably disposed within a valve guide 1006 and can include a first end 1008 and an opposite second end 1010. The first end 1008 can be coupled to a spring keeper 1012, and the second end 1010 can include one or more ports 1014 formed therethrough. A biasing mechanism 1016 (e.g., a spring) can be disposed between the spring keeper 1012 and the cylinder head 1018 to bias the outer valve 1004 in an upward direction (as viewed in the FIGS.) into a closed position.

[0097] The typical engine valve on an internal combustion engine opens against engine cylinder compression. The force required to open an engine valve against engine compression is directly related to the size of the engine cylinder head. Nested engine valve 1000 provides an engine valve that requires a lower opening force while still maintaining a larger engine valve. When a force is applied to a top 1020 of the engine valve 1000, the smaller inner valve 1002 opens before the larger outer valve 1004. As such, the smaller inner valve 1002 opens first and relieves the built up pressure in the cylinder. Once the pressure is relieved, the larger outer valve 1004 can open to allow the cylinder to breathe. Accordingly, since the smaller inner valve 1002 has a smaller surface area, less force is required to open the inner valve 1002 to decompress the piston. As such, a reduced amount of energy is required to open the engine valve 1000 against pressure, thereby reducing vehicle fuel consumption.

[0098] FIG. 22 illustrates nested engine valve 1000 in a closed position. FIG. 23 illustrates nested engine valve 1000 in a decompression stroke position wherein only the smaller inner valve 1002 is opened. FIG. 24 illustrates nested engine valve 1000 in a full stroke position where both inner and outer valves 1002, 1004 are opened.

[0099] FIGS. 25-27 illustrate another embodiment of nested engine valve 1000 that includes an inner valve 1052 slidably disposed within an outer valve 1054. The outer valve 1054 can be slidably disposed within a valve guide 1056 and can include a first end 1058 and an opposite second end 1060. The first end 1058 can be coupled to a spring keeper 1062, and the second end 1060 can include one or more ports 1064 formed therethrough. A biasing mechanism 1066 (e.g., a spring) can be disposed between the spring keeper 1062 and the cylinder head 1068 to bias the outer valve 1054 in an upward direction (as viewed in the FIGS.) into a closed position.

[0100] Moreover, outer valve first end 1058 can include a bore 1070 configured to receive a second biasing mechanism 1072 (e.g., a spring) disposed between outer valve 1054 and a flange or top 1074 of the inner valve 1052. Biasing mechanism 1072 can be configured to bias the inner valve 1052 in an upward direction (as viewed in the FIGS.) into a seated position within outer valve 1054 (see FIG. 25).

[0101] As previously noted, the typical engine valve on an internal combustion engine opens against engine cylinder compression, and the force required to open an engine valve against engine compression is directly related to the size of the engine cylinder head. Nested engine valve 1000 provides an engine valve that requires a lower opening force while still maintaining a larger engine valve. When a force is applied to the top 1074 of the engine valve 1000, the smaller inner valve 1052 opens before the larger outer valve 1054. As such, the smaller inner valve 1052 opens first and relieves the built up pressure in the cylinder. Once the pressure is relieved, the larger outer valve 1054 can open to allow the cylinder to breathe. Accordingly, since the smaller inner valve 1052 has a smaller surface area, less force is required to open the inner valve 1052 to decompress the piston. As such, a reduced amount of energy is required to open the engine valve 1000 against pressure, thereby reducing vehicle fuel consumption.

[0102] FIG. 25 illustrates nested engine valve 1000 in a closed position. FIG. 26 illustrates nested engine valve 1000 in a decompression stroke position wherein only the smaller inner valve 1052 is opened. FIG. 27 illustrates nested engine valve 1000 in a full stroke position where both inner and outer valves 1052, 1054 are opened.

[0103] In other embodiments, the cylinder heads described herein can utilize vehicle fuel (e.g. , gasoline, diesel) as the driving fluid for the hydraulic actuators (e.g., 104, 222, 708) instead of oil or in combination with oil. High pressure fuel is typically available on vehicle engines for a common rail fuel injection system (e.g., 212, 704). The high pressure fuel can be utilized to power the camless hydraulic actuators (104, 222, 708). In some embodiments, a pressure intensifier (not shown) can be placed between the high pressure fuel line and the hydraulic oil line in order to transfer the high pressure of the fuel line to the hydraulic oil line. As such, the high pressure fuel at least partially powers or actuates the camless actuators (104, 222, 708).

[0104] In one example, high pressure fuel can be used to power the common rail fuel injection system and camless actuators using the common rail fuel pump. The high pressure fuel can interact directly with the camless system without the need for pressurized oil. In another example, a pressure intensifier or reducer can be used between the high pressure fuel and the hydraulic oil in order to actuate the camless actuators.

[0105] With reference now to FIG. 28, in other embodiments, a cylinder head (e.g., 100) with both cam and camless engine valve systems can operate in a normal intake lift profile with cam based actuators (e.g., mechanically actuated by a cam/rocker arm), as shown by line 1 102. However, the camless side of the cylinder head can be operated with a lower lift, as shown by line 1 104, which reduces energy usage while providing the same flow. Moreover, the camless side of the cylinder head can utilize proud engine valves such as, for example, proud-style engine valve 900 illustrated in FIG. 21. This further reduces the lift, as shown by line 1 106, which further reduces energy usage while providing the same flow.

[0106] With reference now to FIGS. 29 and 30, in other embodiments, a cylinder head (e.g., 100) with both a cam and camless engine valve systems can be designed to lower the camless actuator lift since energy usage to open the engine valve is proportional to lift. The lower the valve lift, the less energy used and the less impact on the vehicle fuel economy. The camless systems open valves against a valve spring, but the valve spring does not put energy back into the system when closing, as occurs with a cam based system. Further, cam based systems require higher lift to increase duration and maintain stability of the valvetrain. However, unlike cam based systems, the camless systems described herein can lift quicker, plateau lift, and close quicker. Accordingly, the camless lift does not need to be as high as cam based lift for equivalent flow.

[0107] FIGS. 29 and 30 illustrate a method of minimizing valve lift and energy usage for a camless actuator on a valvetrain having both cam and camless valve actuation systems. A first step includes determining at what point the port for each engine valve is choked (i.e., maximum flow volume), as shown by lines 1120 and 1 122 in FIG. 29. A second step includes determining which port will choke (i.e. , reach maximum flow volume) first. For example, as shown in FIG. 29, port two (line 1122) chokes before port one (line 1 120). The port that chokes first is chosen to accept the camless actuator (e.g., 104, 222, 708), while the port that chokes second is chosen to accept the cam based actuator. Accordingly, as shown in FIG. 30, the camless actuator can have a more aggressive lift (line 1 130) (e.g. , greater slope) than the cam based system (line 1 140). As such, for equivalent opening and closing, the flow created by the camless system will be equal to or greater than the flow created by the cam based system.

[0108] A third step includes lowering the camless lift with equivalent opening and closing to the cam based system for equivalent flow into the cylinder (intake) and equivalent flow out for the exhaust. This lowering of the camless lift is represented by line 1150 in FIG. 30. A fourth step includes altering the opening and closing (within cam based opening and closing) for the valve with the camless actuator to further lower the lift and obtain equivalent flow (or a little less) and still maintain engine power at a rated speed. This further lowering of the camless lift is represented by line 1160 in FIG. 30.

[0109] A fifth step includes implementing a proud-style engine valve (e.g., 900) or more flow efficient valve seats on the head such that the valve lift of the camless actuator can be further lowered to achieve equivalent or higher flow than the cam based system. This further lowering of the camless lift due to the implementation of proud-style valve or more flow efficient valve seats is represented by line 1 170 in FIG. 30.

[0110] The foregoing description of the examples has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular example are generally not limited to that particular example, but, where applicable, are interchangeable and can be used in a selected example, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.