LIFT CAPABILITIES

CROSS-REFERENCE TO RELATED APPLICATION:

[0001] The present application claims the benefit of the filing date of U.S. Provisional Application Ser. No. 63/239,539 filed on September 1, 2021, which is incorporated herein by reference.

BACKGROUND

[0002] The present invention relates to an internal combustion engine system, and more particularly, but not exclusively, relates to valve trains for internal combustion engines that include a rocker system with cylinder deactivation and selective valve lift capabilities.

[0003] Cylinder deactivation at low engine loads can be accomplished by leaving the intake and exhaust valves of part of the engine cylinders closed during certain operating conditions to save fuel and operate with increased efficiency. Cylinder deactivation typically requires switching the cam profile that operates on the deactivated cylinders from a nominal profile to a zero profile. Compression release braking can be accomplished with cam profiles that open the exhaust valves for a braking lift during corresponding crank angles that provide compression release from the cylinders. Thus, there is a continuing demand for further contributions in this area of technology.

SUMMARY

[0004] In an embodiment of the present application, a rocker system for an internal combustion engine is disclosed. The rocker system includes at least one input rocker lever rotatable about an engine component in response to motion received from at least one camshaft lobe of a camshaft. The rocker system also includes at least one output rocker lever rotatable about the engine component. The at least one output rocker lever is configured to control opening and closing of at least one exhaust valve or at least one intake valve associated with a cylinder of the internal combustion engine. The rocker system also includes at least one valve lift switch operable to connect the at least one input rocker lever and the at least one output rocker lever to one another for transferring motion from the at least one camshaft lobe to the at least one exhaust valve or the at least one intake valve, and disconnect the at least one input rocker lever and the at least one output rocker lever from one another. The rocker system further includes at least one additional input rocker lever or output rocker lever connectable to the at least one output rocker lever with the at least one valve lift switch.

[0005] In another embodiment, a rocker system for an internal combustion engine is disclosed. The rocker system includes a first input rocker lever rotatable about an engine component in response to motion received from a first camshaft lobe of a camshaft, and a second input rocker lever rotatable about an engine component in response to motion received from a second camshaft lobe of the camshaft. The rocker system includes at least one output rocker lever rotatable about the engine component, and the at least one output rocker lever being configured to control opening and closing of at least one exhaust valve or at least one intake valve associated with a cylinder of the internal combustion engine. The rocker system includes a first valve lift switch and a second valve lift switch. The first valve lift switch is operable to connect the first input rocker lever to the at least one output rocker lever to transfer motion from the first camshaft lobe to the at least one exhaust valve or the at least one intake valve. The second valve lift switch is operable to connect the second input rocker lever to the at least one output rocker lever to transfer motion from the second camshaft lobe to the at least one exhaust valve or the at least one intake valve. The first and second valve lift switches are operable to disconnect the respective first and second input rocker levers from the at least one output rocker lever so that motion from the first and second camshaft lobes is not transferred to the at least one output rocker lever. [0006] This summary is provided to introduce a selection of concepts that are further described below in the illustrative embodiments. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a schematic view of one embodiment of an internal combustion engine system with a valve train that provides alternate valve lift and cylinder deactivation capabilities for at least one cylinder.

[0008] FIG. 2 is a diagrammatic and schematic view of one embodiment of a cylinder of the internal combustion engine system of FIG. 1 and a schematic of a valve actuation mechanism. [0009] FIG. 3 is a graphical representation of example lift profiles for the intake valves and the exhaust valves of the cylinders of the internal combustion engine system of FIG. 1 during a standard operating mode and an exemplary braking operating mode.

[0010] FIG. 4 is a perspective view showing a valve actuation system and the intake valves and the exhaust valves of a cylinder of the internal combustion engine system of FIG. 1.

[0011] FIG. 5 is an elevation view of the valve actuation system and the intake valves and the exhaust valves of FIG. 4.

[0012] FIG. 6 is a perspective of one embodiment of a rocker system of the valve actuation system of FIG. 4.

[0013] FIG. 7 is a plan view of the rocker system of FIG. 6.

[0014] FIG. 8 is an elevation view of the rocker system of FIG. 6.

[0015] FIGs. 9-11 are sectional views of the rocker system of FIG. 6 showing standard lift, cylinder deactivation, and auxiliary lift operating modes, respectively.

[0016] FIG. 12 is an elevation view of another embodiment of a rocker system for a cylinder of the internal combustion engine of FIG. 1.

[0017] FIG. 13 is a plan view of the rocker system of FIG. 12.

[0018] FIGs. 14-16 are sectional views of the rocker system of FIG. 12 showing standard lift, cylinder deactivation, and braking operating modes, respectively.

[0019] FIGs. 17-18 are section views showing an assembly method for the rocker system of FIG. 12.

[0020] FIG. 19 is a perspective view of another embodiment of a rocker system for a cylinder of the internal combustion engine of FIG. 1.

[0021] FIGs. 20-22 are section views of the rocker system of FIG. 19 showing standard lift, cylinder deactivation, and braking operating modes, respectively.

[0022] FIG. 23 is another section view of the rocker system of FIG. 19 showing a stop pin. [0023] FIG. 24 is a perspective view of the rocker system of FIG. 23 showing the stop pin.

[0024] FIG. 25 is a perspective view of another embodiment of a rocker system for a cylinder of the internal combustion engine of FIG. 1.

[0025] FIG. 26 is a plan view of the rocker system of FIG. 25.

[0026] FIG. 27 is an elevation view of the rocker system of FIG. 25.

[0027] FIG. 28 is a section view of the rocker system of FIG. 25.

[0028] FIG. 29 is a perspective view of another embodiment of a rocker system for a cylinder of the internal combustion engine of FIG. 1.

[0029] FIG. 30 is a section view of the rocker system of FIG. 29.

[0030] FIG. 31 is a plan view of another embodiment of intake and exhaust side rocker systems for two cylinders of the internal combustion engine of FIG. 1.

[0031] FIG. 32 is a section view of an exhaust side rocker system of FIG. 31.

[0032] FIG. 33 is a plan view of another embodiment rocker system for a cylinder of the internal combustion engine of FIG. 1.

[0033] FIG. 35 is a plan view of another embodiment rocker system for a cylinder of the internal combustion engine of FIG. 1.

[0034] FIG. 36 is a plan view of another embodiment rocker system for a cylinder of the internal combustion engine of FIG. 1.

[0035] FIG. 37 is a plan view of another embodiment rocker system for a cylinder of the internal combustion engine of FIG. 1.

[0036] FIG. 38 is a plan view of another embodiment rocker system for a cylinder of the internal combustion engine of FIG. 1.

[0037] FIG. 39 is a plan view of another embodiment rocker system for a cylinder of the internal combustion engine of FIG. 1.

[0038] FIG. 40 is a plan view of another embodiment rocker system for a cylinder of the internal combustion engine of FIG. 1.

[0039] FIG. 41 is a plan view of another embodiment rocker system for a cylinder of the internal combustion engine of FIG. 1. DETAILED DESCRIPTION OF REPRESENTATIVE EMBODIMENTS

[0040] While the present invention can take many different forms, for the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications of the described embodiments, and any further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates.

[0041] With reference to FIGs. 1-41, embodiments of the present application include unique systems that operate one or more cylinders 14 of an internal combustion engine 12 using one or more of cylinder deactivation for low load efficiency improvement, standard or nominal lift for the intake and/or exhaust valves of the cylinders 14, and selective lift for one or more of the cylinders 14 in order to provide, for example, compression release braking or swirl in the corresponding cylinder 14. Other embodiments include systems relating to an internal combustion engine system 10 with a valve train that is configured so that one or more cylinders 14 can operate under nominal exhaust valve and intake valve lifts, cylinder deactivation, and/or selective intake and/or exhaust valve lifts that vary in lift height and/or lift timing from the standard lift thereof.

[0042] In an embodiment, a rocker system 100, 300, 500, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700 for an internal combustion engine 12 is disclosed herein according to an embodiment of the disclosure. The rocker system 100, 300, 500, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700 includes at least one input rocker lever 104, 106, 108, 304, 306, 308, 504, 506, 508, 706, 806, 808, 904, 906, 994, 996, 1010, 1110, 1202, 1310, 1410, 1412, 1510, 1512, 1514, 1610, 1612, 1710, 1712 rotatable about an engine component 120 in response to motion received from at least one camshaft lobe 92a, 94a, 92b, 94b, 92c, 94c of a camshaft 92, 94, and at least one output rocker lever 102, 302, 502, 702, 704, 802, 804, 902, 992, 1002, 1004, 1102, 1302, 1304, 1402, 1502, 1504, 1602, 1702, 1802 rotatable about the engine component 120. The at least one output rocker lever 102, 302, 502, 702, 704, 802, 804, 902, 992, 1002, 1004, 1102, 1302, 1304, 1402, 1502, 1504, 1602, 1702, 1802 is configured to control opening and closing of at least one exhaust valve 24 or at least one intake valve 22 associated with a cylinder 14 of the internal combustion engine 12. The rocker system 100, 300, 500, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700 includes at least one valve lift switch 150, 200, 350, 400, 550, 600, 750, 850, 870, 920, 940 operable to connect the at least one input rocker lever 104, 106, 108, 304, 306, 308, 504, 506, 508, 706, 806, 808, 904, 906, 994, 996, 1010, 1110, 1202, 1310, 1410, 1412, 1510, 1512, 1514, 1610, 1612, 1710, 1712 and the at least one output rocker lever 102, 302, 502, 702, 704, 802, 804, 902, 992, 1002, 1004, 1102, 1302, 1304, 1402, 1502, 1504, 1602, 1702, 1802 to one another for transferring motion from the at least one camshaft lobe 92a, 94a, 92b, 94b, 92c, 94c to the at least one exhaust valve 24 or the at least one intake valve 22, and disconnect the at least one input rocker lever 104, 106, 108, 304, 306, 308, 504, 506, 508, 706, 806, 808, 904, 906, 994, 996, 1010, 1110, 1202, 1310, 1410, 1412, 1510, 1512, 1514, 1610, 1612, 1710, 1712 and the at least one output rocker lever 102, 302, 502, 702, 704, 802, 804, 902, 992, 1002, 1004, 1102, 1302, 1304, 1402, 1502, 1504, 1602, 1702, 1802 from one another. The rocker system 100, 300, 500, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700 includes at least one additional input rocker lever or output rocker lever 102, 302, 502, 702, 704, 802, 804, 902, 992, 1002, 1004, 1102, 1302, 1304, 1402, 1502, 1504, 1602, 1702, 1802 connectable to the at least one output rocker lever 102, 302, 502, 702, 704, 802, 804, 902, 992, 1002, 1004, 1102, 1302, 1304, 1402, 1502, 1504, 1602, 1702, 1802 with the at least one valve lift switch 150, 200, 350, 400, 550, 600, 750, 850, 870, 920, 940.

[0043] According to another embodiment of the present disclosure, a rocker system 100, 300, 500, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700 for an internal combustion engine 12 is disclosed. The rocker system 100, 300, 500, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700 includes a first input rocker lever 104, 304, 504, 706, 806, 904, 994, 1010, 1110, 1202, 1310, 1410, 1510, 1610, 1710 rotatable about an engine component 120 in response to motion received from a first camshaft lobe 92a, 94a of a camshaft 92, 94; a second input rocker lever 106, 108, 306, 308, 506, 508, 808, 906, 996, 1412, 1512, 1514, 1612, 1712 rotatable about the engine component 120 in response to motion received from a second camshaft lobe 92b, 94b of the camshaft 92, 94; and at least one output rocker lever 102, 302, 502, 702, 704, 802, 804, 902, 992, 1002, 1004, 1102, 1302, 1304, 1402, 1502, 1504, 1602, 1702, 1802 rotatable about the engine component 120. The at least one output rocker lever 102, 302, 502, 702, 704, 802, 804, 902, 992, 1002, 1004, 1102, 1302, 1304, 1402, 1502, 1504, 1602, 1702, 1802 is configured to control opening and closing of at least one exhaust valve 24 or at least one intake valve 22 associated with a cylinder 14 of the internal combustion engine 12. The rocker system 100, 300, 500, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700 also includes a first valve lift switch 150, 350, 550, 750, 850, 920 and a second valve lift switch 200, 400, 600, 870, 940. The first valve lift switch 150, 350, 550, 750, 850, 920 is operable to connect the first input rocker lever 104, 304, 504, 706, 806, 904, 994, 1010, 1110, 1202, 1310, 1410, 1510, 1610, 171 O to the at least one output rocker lever 102, 302, 502, 702, 704, 802, 804, 902, 992, 1002, 1004, 1102, 1302, 1304, 1402, 1502, 1504, 1602, 1702, 1802 to transfer motion from the first camshaft lobe 92a, 94a to the at least one exhaust valve 24 or the at least one intake valve 22. The second valve lift switch 200, 400, 600, 870, 940 is operable to connect the second input rocker lever 106, 108, 306, 308, 506, 508, 808, 906, 996, 1412, 1512, 1514, 1612, 1712 to the at least one output rocker lever 102, 302, 502, 702, 704, 802, 804, 902, 992, 1002, 1004, 1102, 1302, 1304, 1402, 1502, 1504, 1602, 1702, 1802 to transfer motion from the second camshaft lobe 92b, 94b to the at least one exhaust valve 24 or the at least one intake valve 22. The first 150, 350, 550, 750, 850, 920 and second valve lift switches 200, 400, 600, 870, 940 are operable to disconnect the respective first 104, 304, 504, 706, 806, 904, 994, 1010, 1110, 1202, 1310, 1410, 1510, 1610, 1710 and second input rocker levers 106, 108, 306, 308, 506, 508, 808, 906, 996, 1412, 1512, 1514, 1612, 1712 from the at least one output rocker lever 102, 302, 502, 702, 704, 802, 804, 902, 992, 1002, 1004, 1102, 1302, 1304, 1402, 1502, 1504, 1602, 1702, 1802 so that motion from the first and second camshaft lobes 92a, 94a, 92b, 94b is not transferred to the at least one output rocker lever 102, 302, 502, 702, 704, 802, 804, 902, 992, 1002, 1004, 1102, 1302, 1304, 1402, 1502, 1504, 1602, 1702, 1802.

[0044] With reference to FIG. 1, an internal combustion engine system 10 is shown that includes, for example, an internal combustion engine 12. Any engine type is contemplated, including compression ignition, spark-ignition, and combinations of these. The engine 12 can include a plurality of cylinders 14. FIG. 1 illustrates the plurality of cylinders 14 in an arrangement that includes six cylinders 14 in an in-line arrangement for illustration purposes only. Any number of cylinders and any arrangement of the cylinders suitable for use in an internal combustion engine 12 can be utilized. The number of cylinders 14 that can be used can range, for example, from two cylinders to eighteen or more. Furthermore, the following description at times will be in reference to one of the cylinders 14. It is to be realized that corresponding features in reference to the cylinder 14 described in FIG. 2 and at other locations herein can be present for all or a subset of the other cylinders 14 of engine 12 unless noted otherwise.

[0045] As discussed herein, internal combustion engine system 10 includes a valve actuation system with a rocker system, embodiments of which are discussed further below, configured to open and close the intake valves and/or the exhaust valves of an associated cylinder 14 of engine 12. The rocker system includes at least one output rocker lever selectively connectable one or more input rocker levers to achieve a functional mode of operation. Functional modes of operation that can be achieved by the rocker system of the present disclosure include, for example, nominal or standard intake and exhaust valve operations, Miller cycling intake valve operations, four stroke engine compression braking exhaust valve operations, cylinder deactivation for the intake and/or exhaust valves, two stroke engine compression braking for the intake and exhaust valves, variable swirl intake valve operation, and/or dynamic skip fire.

[0046] One exemplary embodiment for the cylinder 14 is shown in FIG. 2, it being understood that any suitable cylinder embodiment is contemplated herein. Cylinder 14 typically houses a piston 16 that is operably attached to a crankshaft 18 that is rotated by reciprocal movement of piston 16 in a combustion chamber 28 of the cylinder 14. Within a cylinder head 20 of the cylinder 14, there is at least one intake valve 22, at least one exhaust valve 24, and in certain embodiments a fuel injector 26 that provides fuel to the combustion chamber 28 formed by cylinder 14 between the piston 16 and the cylinder head 20. In other embodiments, fuel can be provided to combustion chamber 28 by port injection, or by injection in the intake system, upstream of combustion chamber 28. Furthermore, in the discussion that follows, each cylinder 14 includes two intake valves 22 and two exhaust valves 24, but such is not required in all embodiments.

[0047] The term “four stroke” herein means the following four strokes - intake, compression, power, and exhaust - that the piston 16 completes during two separate revolutions of the engine’s crankshaft 18, which is a combustion cycle. A stroke begins either at a top dead center (TDC) when the piston 16 is at the top of cylinder head 20 of the cylinder 14, or at a bottom dead center (BDC), when the piston 16 has reached its lowest point in the cylinder 14.

[0048] Referring further to FIG. 3, there is shown example nominal or standard intake and exhaust valve opening and closing profiles during a combustion cycle for the intake valves (IV1) and the exhaust valves (EVI). During the intake stroke for IV1, the piston 16 descends away from cylinder head 20 of the cylinder 14 to a bottom (not shown) of the cylinder, thereby reducing the pressure in the combustion chamber 28 of the cylinder 14. A combustion charge is created in the combustion chamber 28 by an intake of air through the intake valves 22 when the intake valves 22 are opened.

[0049] The fuel from the fuel injector 26 can be supplied by, for example, a high pressure common-rail system 30 (FIG. 1) that is connected to the fuel tank 32. Fuel from the fuel tank 32 is suctioned by a fuel pump (not shown) and fed to the common-rail fuel system 30. The fuel fed from the fuel pump is accumulated in the common-rail fuel system 30, and the accumulated fuel is supplied to the fuel injector 26 of each cylinder 14 through a fuel line 34. The accumulated fuel in common rail system can be pressurized to boost and control the fuel pressure of the fuel delivered to combustion chamber 28 of each cylinder 14. However, as mentioned above, any type of fuel delivery system is contemplated.

[0050] During the compression stroke in a standard mode of operation, the intake valves 22 and the exhaust valves 24 are closed as shown by IV1 and EVI in FIG. 3. The piston 16 returns toward TDC and fuel is injected near TDC in the compressed air in a main injection event, and the compressed fuel-air mixture ignites in the combustion chamber 28 after a short delay. In the instance where the engine 12 is a diesel engine, this results in the combustion charge being ignited. The ignition of the air and fuel causes a rapid increase in pressure in the combustion chamber 28, which is applied to the piston 16 during its power stroke toward the BDC. Combustion phasing in combustion chamber 28 is calibrated so that the increase in pressure in combustion chamber 28 pushes piston 16, providing a net positive in the force/work/power of piston 16.

[0051] During the exhaust stroke, the piston 16 is returned toward TDC while the exhaust valves 24 are open, as shown by EVI in FIG. 3. This action discharges the burnt products of the combustion of the fuel in the combustion chamber 28 and expels the spent fuel-air mixture (exhaust gas) out through the exhaust valves 24. The next combustion cycle occurs using these same intake and exhaust valve opening closing profiles, unless a cylinder deactivation condition or alternative valve lift condition is desired, as discussed further below.

[0052] Referring back to FIG. 1, the intake air flows through an intake passage 36 and intake manifold 38 before reaching the intake valves 22. The intake passage 36 may be connected to a compressor 40a of a turbocharger 40 and an intake throttle 42. The intake air can be purified by an air cleaner (not shown), compressed by the compressor 40a and then aspirated into the combustion chamber 28 through the intake throttle 42. The intake throttle 42 can be controlled to influence the air flow into the cylinder(s) 14.

[0053] The intake passage 36 can be further provided with an optional cooler 44 that is provided downstream of the compressor 40a. In one example, the cooler 44 can be a charge air cooler (CAC). In this example, the compressor 40a can increase the temperature and pressure of the intake air, while the CAC 44 can increase a charge density and provide more air to the cylinders. In another example, the cooler 44 can be a low temperature aftercooler (LTA). The CAC 44 uses air as the cooling media, while the LTA uses coolant as the cooling media.

[0054] The exhaust gas flows out from the combustion chamber 28 into an exhaust passage 46 from an exhaust manifold 48 that connects the cylinders 14 to exhaust passage 46. The exhaust passage 46 is connected to a turbine 40b and a wastegate 50 of the turbocharger 40 and then into an aftertreatment system 52. The exhaust gas that is discharged from the combustion chamber 28 drives the turbine 40b to rotate. The wastegate 50 is a device that enables part of the exhaust gas to by-pass the turbine 40b through a passageway 54. The wastegate 50 can include a control valve 56 that can be an open/closed (two position) type of valve, or a full authority valve allowing control over the amount of by-pass flow, or anything between. The exhaust passage 46 can further or alternatively include an exhaust throttle 58 for adjusting the flow of the exhaust gas through the exhaust passage 46. The exhaust gas, which can be a combination of by-passed and turbine flow, then enters the aftertreatment system 52. Other embodiments contemplate a variable inlet turbine, systems with no turbine, and/or systems with no compressor.

[0055] Optionally, a part of the exhaust gas can be recirculated into the intake system via an EGR passage (not shown.) The EGR passage can be connected the exhaust passage upstream of the turbine 40b to the intake passage 36 downstream of the intake air throttle 42. Alternatively or additionally, a low pressure EGR system (not shown) can be provided downstream of turbine 40b and upstream of compressor 40a. An EGR valve can be provided for regulating the EGR flow through the EGR passage. The EGR passage can be further provided with an EGR cooler and a bypass around the EGR cooler.

[0056] The aftertreatment system 52 may include one or more devices useful for handling and/or removing material from exhaust gas that may be harmful constituents, including carbon monoxide, nitric oxide, nitrogen dioxide, hydrocarbons, and/or soot in the exhaust gas. In some examples, the aftertreatment system 52 can include at least one of a catalytic device and a particulate matter filter. The catalytic device can be a diesel oxidation catalyst (DOC) device, ammonia oxidation (AMOX) catalyst device, a selective catalytic reduction (SCR) device, three- way catalyst (TWC), lean NOX trap (LNT) etc. The reduction catalyst can include any suitable reduction catalysts, for example, a urea selective reduction catalyst. The particulate matter filter can be a diesel particulate filter (DPF), a partial flow particulate filter (PFF), etc. A PFF functions to capture the particulate matter in a portion of the flow; in contrast the entire exhaust gas volume passes through the particulate filter.

[0057] A controller 80 is provided to receive data as input from various sensors, and send command signals as output to various actuators. Some of the various sensors and actuators that may be employed are described in detail below. The controller 80 can include, for example, a processor, a memory, a clock, and an input/output (VO) interface.

[0058] The system 10 includes various sensors such as an intake manifold pressure/temperature sensor 70, an exhaust manifold pressure/temperature sensor 72, one or more aftertreatment sensors 74 (such as a differential pressure sensor, temperature sensor(s), pressure sensor(s), constituent sensor(s)), engine sensors 76 (which can detect the air/fuel ratio of the air/fuel mixture supplied to the combustion chamber, a crank angle, the rotation speed of the crankshaft, etc ), and a fuel sensor 78 to detect the fuel pressure and/or other properties of the fuel, common rail 38 and/or fuel injector 26. Any other sensors known in the art for an engine system are contemplated.

[0059] System 10 can also include various actuators for opening and closing the intake valves 22, for opening and closing the exhaust valves 24, for injecting fuel from the fuel injector 26, for opening and closing the wastegate valve 56, for the intake throttle 42, and/or for the exhaust throttle 58. The actuators are not illustrated in FIG. 1, but one skilled in the art would know how to implement the mechanism needed for each of the components to perform the intended function. Furthermore, in one embodiment, the actuators for opening and closing the intake and exhaust valves 22, 24 are provided as a part of a valve actuation (VA) system 90, such as shown schematically in FIG. 2.

[0060] Referring to FIGs. 4-11, further details regarding one embodiment of VA system 90 is shown that is applicable to provide cylinder deactivation of one or more of the cylinders 14 under cylinder deactivation conditions and/or an alternative lift profile for the intake and/or exhaust valve(s) of the one or more cylinders 14, in addition to the standard lift profile discussed above. FIGs. 4-5 show a first VA system 90a for the intake side and a second VA system 90b for the exhaust side, which may be collectively and individually referred to herein as VA system 90. The VA system 90 can be provided for operation of one or both of the intake valves 22, for operation of one or both of the exhaust valves 24, for operation of one of the intake valves 22 and one of the exhaust valves 24, or for operation of all of the intake and exhaust valves 22, 24. In addition, the VA system 90a can provide one or more lift profiles for the intake valves 22 that differ from the one or more lift profiles for the exhaust valves 24.

[0061] Specifically, the VA system 90a includes a rocker system 100a that is configured to engage the lobes of the intake side camshaft 92 along one of more of the cylinders 14. Alternatively or additionally, the VA system 90b may include a same, similar, or different rocker system 100b that is configured to engage the lobes of the exhaust side camshaft 94 along one of more of the cylinders 14. The rocker systems 100a, 100b may be individually or collectively referred to as rocker system 100 herein.

[0062] In the illustrated embodiment, camshaft 92 includes three camshaft lobes 92a, 92b, 92c that provide at least two different valve lift profiles for the intake valves 22, and camshaft 94 includes three camshaft lobes 94a, 94b, 94c that provide at least two different valve lift profiles for the exhaust valves 94. Other embodiments contemplate only two lobes, or more than three lobes, on one or both of the camshafts 92, 94. The three camshaft lobes of the respective camshaft in the illustrated embodiment may provide, for example, a nominal or standard lift profile for the associated valve(s) 22, 24 and one or more auxiliary lift profiles for the associated valve(s) 22, 24 that differs from the standard lift profile in height and/or timing of the valve lift from its respective valve seat.

[0063] Referring further to FIGs. 6-8, rocker system 100 includes an output rocker lever 102, a first input rocker lever 104, a second input rocker lever 106, and a third input rocker lever 108 that are each rotatably mounted to an engine component 120, such as a rocker shaft, in side-by- side relation. First input rocker lever 104 includes a first roller 110 that is direct or indirect contact with the corresponding camshaft lobe 92a, 94a. Second input rocker lever 106 includes a second roller 112 that is direct or indirect contact with the corresponding camshaft lobe 92b, 94b. Third input rocker lever 108 includes a third roller 114 that is direct or indirect contact with the corresponding camshaft lobe 92c, 94c. [0064] As discussed further below, one or more of the input rocker levers 104, 106, 108 is controlled to be selectively connectable with the output rocker lever 102 to transfer motion from the respective camshaft lobe(s) 92a, 94a, 92b, 94b, 92c, 94c to the connected one(s) of the intake valves 22 or exhaust valves 24. In addition, the input rocker levers 104, 106, 108 can be controlled to be selectively disconnected from the output rocker lever 102 so that no valve lift is provided during cylinder deactivation. The controllable connection and disconnection of output rocker 102 and input rockers 104, 106, and/or 108 can occur by engagement from output rocker 102 to input rockers 104, 106, and/or 108; by engagement from input rockers 104, 106, and/or 108 to output rocker 102; and combinations thereof.

[0065] A biasing mechanism 122 includes springs 124, 126, 128 that are each in contact with output rocker lever 102 and with respective ones the input rocker levers 104, 106, 108 to bias the corresponding rollers 110, 112, 114 into direct or indirect contact with the respective camshaft lobes 92a, 94a, 92b, 94b, 96a, 96c. Hydraulic lash adjusters 130, 132 also illustrated that are connected to respective arms 102a, 102b of the output rocker lever 102 and also to the corresponding ones of the intake valves 22 or exhaust valves 24. The lash adjusters 130, 132 may also be mechanical lash adjusters. Biasing mechanism 122 is located on a side of rocker system 100 opposite hydraulic lash adjusters 130, 132 in the illustrated embodiment, although such positioning is not required.

[0066] In another embodiment, an adjusting screw or elephant foot may be provided in lieu of or in addition to lash adjusters 130, 132. A rocker pedestal 134 may also be provided for mounting to the cylinder head 20, but embodiments without a rocker pedestal 134 are also contemplated. In addition, embodiments without a rocker shaft are contemplated, with the rocker levers being mountable about any suitable engine component 120, such as an end-pivot integrated into the cylinder head to which the rocker lever(s) are mounted.

[0067] The rocker system 100 includes a first valve lift switch 150 that is controlled for selectively connecting and disconnecting first input rocker lever 104 and output rocker lever 102 to one another to transfer motion from or prevent the transfer of motion from the associated camshaft lobe 92a, 94a to the connected ones of the intake and/or exhaust valves 22, 24. The rocker system 100 also includes a second valve lift switch 200 that is controlled for selectively connecting and disconnecting one or both of second and third input rocker levers 106, 108 and output rocker lever 102 to one another to transfer motion from or prevent the transfer of motion from the associated camshaft lobes 92b, 94b, 92c, 94c to the connected ones of the intake and/or exhaust valves 22, 24.

[0068] Referring further to FIGs. 9-11, first valve lift switch 150 is housed in a bore 152 that extends in and from output rocker lever 102 to first input rocker lever 104. First switch 150 includes a first valve lift pin assembly 154 that includes a spring-biased first valve lift pin 156 comprising multiple shear pin parts 170, 172, 174 in abutting, end-to-end engagement. First valve lift pin 156 is normally biased via springs 158a, 158b to an engaged position such that first input rocker lever 104 is connected to output rocker lever 102, as shown in FIG. 9. In the engaged position, the valve lift pin 156 spans the joints 160, 162 between the rocker levers 102, 104, forming shear interfaces 160a, 162a at joints 160, 162. The engaged position of first valve lift switch 150 is used during operating conditions in which the standard or nominal lift for the intake or exhaust valves 22, 24 is desired from the camshaft lobes 92a, 94a.

[0069] In order to disconnect or decouple rocker levers 102, 104 from one another, hydraulic fluid pressure is supplied into bore 152 from the rocker shaft 120 of engine 12 via the hydraulic system of engine 12 through opening 166, and into the space 164 at one end of bore 152. The hydraulic pressure displaces valve lift pin 156 into contact with base 168, compressing springs 158a, 158b, as shown in FIG. 10 and FIG. 11. In this condition, the junction between shear pin parts 170, 172 is aligned with joint 160, and the junction between shear pin parts 172, 174 is aligned with joint 162. This disengaged position removes the shear interfaces 160a, 162a since no part of first valve lift pin 156 spans the joints 160, 162. As a result, rotation of the first input rocker lever 104 is not transferred to output rocker lever 102, and the motion imparted by the camshaft lobes 92a, 94a is not transferred to the intake or exhaust valves 22, 24 but rather is taken up by the bias spring 124. The disengaged position for first valve lift switch 150 is used during operating conditions in which cylinder deactivation is desired, and/or during which an alternate lift profile from the second and third input rockers 106, 108 is desired from camshaft lobes 92b, 94b, 92c, 94c.

[0070] Second valve lift switch 200 is housed in a bore 202 that extends in and from output rocker lever 102, to second input rocker lever 106, and to third input rocker lever 108. Second valve lift switch 200 includes a second valve lift pin assembly 204 that includes a second valve lift pin 206 comprising multiple shear pin parts 220, 222 in abutting, end-to-end engagement. Second valve lift pin 206 is normally biased via spring 208 to a disengaged position, as shown in FIGs. 9 and 10.

[0071] In the engaged position shown in FIG. 11, the second input rocker lever 106 and third input rocker lever 108 are connected to output rocker lever 102. In the engaged position, the valve lift pin 206 spans the joints 210, 212 between the rocker levers 102, 106, 108, forming shear interfaces 210a, 212a at joints 210, 212. The engaged position of second valve lift switch 200 is used during operating conditions in which the alternative lift for the intake or exhaust valves 22, 24 is desired from the camshaft lobes 92b, 94b, 92c, 94c via the input rocker levers 106, 108. In order to connect or couple rocker levers 102, 106, 108 to one another, hydraulic fluid pressure is supplied into bore 202 from rocker shaft 120 of engine 12 via the hydraulic system of engine 12 through an opening 216, and into the control pressure space 214 at one end of bore 202. The hydraulic fluid pressure displaces valve lift pin 206 into contact with base 218, compressing spring 208, as shown in FIG. 11.

[0072] In the disengaged condition of FIGs. 9 and 10, the junction between shear pin parts 220, 222 is aligned with joint 210, and the end of shear pin part 222 is located within output rocker lever 102 so that shear pin part 222 does not span joint 212. This disengaged position removes the shear interfaces 210a, 212a since no part of second valve lift pin 206 spans the joints 210, 212. As a result, rotation of the second and third input rocker levers 106, 108 are not transferred to output rocker lever 102, and the motion imparted by the camshaft lobes 92b, 94b, 92c, 94c is not transferred to the intake or exhaust valves 22, 24 but rather taken up by bias springs 126, 128. The disengaged position for second valve lift switch 200 is used during operating conditions in which cylinder deactivation is desired, or during which a nominal or standard lift profde from the first input rocker 104 is desired from camshaft lobes 92a, 94a.

[0073] FIGs. 12-18 illustrate another embodiment rocker system 300. Rocker system 300 can be similar to rocker system 100 discussed above, and the discussion that follows is directed to further features of rocker system 300. One or more aspects or features of rocker system 100 discussed above can be provided for rocker system 300, and vice versa.

[0074] Referring to FIGs. 12-13, rocker system 300 includes an output rocker lever 302, a first input rocker lever 304, a second input rocker lever 306, and a third input rocker lever 308 that are each rotatably mountable to an engine component 120, such as rocker shaft. First input rocker lever 304 includes a first roller 310 for direct or indirect contact with the corresponding camshaft lobe 92a, 94a. Second input rocker lever 306 includes a second roller 312 for direct or indirect contact with the corresponding camshaft lobe 92b, 94b. Third input rocker lever 308 includes a third roller 314 that is direct or indirect contact with the corresponding camshaft lobe 92c, 94c.

[0075] One or more of the input rocker levers 304, 306, 308 is selectively connectable with the output rocker lever 302 to transfer motion from the respective camshaft lobe(s) 92a, 94a, 92b, 94b, 92c, 94c to the connected one(s) of the intake valves 22 or exhaust valves 24. In addition, the input rocker levers 304, 306, 308 can be disconnected from the output rocker lever 302 so that no valve lift is provided during cylinder deactivation. The connection and disconnection of output rocker 302 and input rockers 304, 306, and/or 308 can occur by engagement from output rocker 302 to input rockers 304, 306, and/or 308; by engagement from input rockers 304, 306, and/or 308 to output rocker 302; and combinations thereof.

[0076] A biasing mechanism 322 includes springs 324, 326, 328 that are each in contact with output rocker lever 302 and a respective one of the input rocker levers 304, 306, 308 to bias the corresponding rollers 310, 312, 314 into direct or indirect contact with the respective camshaft lobes. Biasing mechanism 322 differs from biasing mechanism 122 in that the spring 324 for the first input rocker lever 304 is provided on the same side of the rocker assembly as the lash adjusters 330, 332. Lash adjusters 330, 332, which can be mechanical or hydraulic, are connected to respective arms 302a, 302b of the output rocker lever 302 and the corresponding ones of the intake valves 22 or exhaust valves 24.

[0077] The rocker system 300 includes a first valve lift switch 350 for selectively connecting and disconnecting first input rocker lever 304 to output rocker lever 302 to transfer motion from or prevent the transfer of motion from the associated camshaft lobe 92a, 94a to the connected ones of the intake and/or exhaust valves 22, 24. The rocker system 300 also includes a second valve lift switch 400 for selectively connecting and disconnecting one or both of second and third input rocker levers 306, 308 to output rocker lever 302 to transfer motion or prevent the transfer of motion from the associated camshaft lobes 92b, 94b, 92c, 94c to the connected ones of the intake and/or exhaust valves 22, 24.

[0078] Referring further to FIGs. 14-16, first valve lift switch 350 is housed in a bore 352 that extends in and from output rocker lever 302 to first input rocker lever 304. First valve lift switch 350 includes a first valve lift pin assembly 354 that includes a first valve lift pin 356 comprising multiple shear pin parts 370, 372 normally biased away from one another via spring 358 to an engaged position such that first input rocker lever 304 is connected to output rocker lever 302, as shown in FIG. 14. In the engaged position, the valve lift pin 356 spans the joints 360, 362 between the rocker levers 302, 304, forming shear interfaces 360a, 362a at joints 360, 362. The engaged position of first switch 350 is used during operating conditions in which the standard or nominal lift for the intake or exhaust valves 22, 24 is desired from the camshaft lobes 92a, 94a. [0079] In order to disconnect or decouple rocker levers 302, 304 from one another, hydraulic fluid pressure is supplied into bore 352 from rocker shaft 120 of the engine 12 via the hydraulic system of engine 12 through openings 366a, 366b, and into the spaces 364a, 364b at the opposite ends of bore 352. The hydraulic fluid pressure displaces shear pin parts 370, 372 toward one another by compressing spring 358, as shown in FIG. 15 and FIG. 16. In this condition, the shear pin parts 370, 372 are moved entirely into first input rocker lever 304. This disengaged position removes the shear interfaces 360a, 362a since no part of first valve lift pin 356 spans the joints 360, 362. As a result, rotation of the first input rocker lever 304 is not transferred to output rocker lever 302, and the motion imparted by the camshaft lobes 92a, 94a is not transferred to the intake or exhaust valves 22, 24. The disengaged position for first valve lift switch 350 is used during operating conditions in which cylinder deactivation is desired, or during which an alternate lift profile from the second and third input rockers 306, 308 is desired from camshaft lobes 92b, 94b, 92c, 94c.

[0080] Second valve lift switch 400 is housed in a bore 402 in output rocker lever 302, second input rocker lever 306, and third input rocker lever 308. Second valve lift switch 400 includes a second valve lift pin assembly 404 that includes a second valve lift pin 406 comprising multiple shear pin parts 420, 422 in bore 402. Shear pin part 420 and shear pin part 422 are normally biased toward one another via springs 408, 409 and against a central base 418 in bore 402 to a disengaged position, as shown in FIGs. 14 and 15.

[0081] In the engaged position shown in FIG. 16, the second input rocker lever 306 and third input rocker lever 308 are connected to output rocker lever 302. In the engaged position, the shear pin parts 420, 422 of shear pin 406 span the joints 410, 412 between the rocker levers 302, 306, 308, forming shear interfaces 410a, 412a at joints 410, 412. The engaged position of second valve lift switch 400 is used during operating conditions in which the alternative lift for the intake or exhaust valves 22, 24 is desired from the camshaft lobes 92b, 94b, 92c, 94c via the input rocker levers 306, 308. In order to connect or couple rocker levers 302, 306, 308 to one another, hydraulic fluid pressure is supplied into bore 402 from the rocker shaft 120 of engine 12 via the hydraulic system of engine 12 through opening 416, and into the control pressure space 414 of bore 402 between shear pin parts 420, 422. The hydraulic fluid pressure displaces shear pin parts 420, 422 off of base 418, compressing springs 408, 409 so that the shear pin parts span joints 410, 412, as shown in FIG. 16.

[0082] In the disengaged condition, the shear pin parts 420, 422 are located within output rocker lever 302 so that shear pin parts 420, 422 do not span joints 410, 412. This disengaged position removes the shear interfaces 410a, 412a since no part of second valve lift pin 406 spans the joints 410, 412. As a result, rotation of the second and third input rocker levers 306, 308 is not transferred to output rocker lever 302, and the motion imparted by the camshaft lobes 92b, 94b, 92c, 94c is not transferred to the intake or exhaust valves 22, 24. The disengaged position for second valve lift switch 400 is used during operating conditions in which cylinder deactivation is desired, or during which a nominal or standard lift profile from the first input rocker lever 304 is desired from camshaft lobes 92a, 94a.

[0083] FIGs. 17-18 show an example assembly process for assembling output rocker lever 302 with first input rocker lever 304. In FIG. 17, shear pin parts 370, 372 can be held in position via temporary assembly pins 450, 452 inserted into assembly bores 454, 456, respectively, in output rocker lever 302. The assembly pins 450, 452 hold the shear pin parts 370, 372 in a retracted position in output rocker lever 302 with spring 358 compressed therebetween. Once the input rocker lever 304 is aligned with output rocker lever 302, the assembly pins 450, 452 can be removed, allowing the shear pin parts 370, 372 to spring into position and span the joints 410, 412 to complete the assembly. Each shear pin part 370, 372 can be provided with a slot 458, 460, respectively, to receive a screwdriver or other tool to assist in aligning the respective shear pin part 370, 372 to receive the corresponding assembly pin 450, 452.

[0084] FIGs. 19-24 illustrate another embodiment rocker system 500. Rocker system 500 can be similar to rocker systems 100, 300 discussed above, and the discussion that follows is directed to further features of rocker system 500. One or more aspects or features of rocker systems 100, 300 discussed above can be provided for rocker system 500, and vice versa.

[0085] Referring to FIG. 19, rocker system 500 includes an output rocker lever 502, a first input rocker lever 504, a second input rocker lever 506, and a third input rocker 508, that are each rotatably mountable to an engine component 120, such as a rocker shaft. First input rocker lever 504 includes a first roller 510 for direct or indirect contact with the corresponding camshaft lobe 92a, 94a. Second input rocker lever 506 includes a second roller 512 for direct or indirect contact with the corresponding camshaft lobe 92b, 94b. Third input rocker lever 508 includes a third roller 514 for direct or indirect contact with the corresponding camshaft lobe 92c, 94c. [0086] One or more of the input rocker levers 504, 506, 508 is controlled to selectively connect with the output rocker lever 502 to transfer motion from the respective camshaft lobe(s) 92a, 94a, 92b, 94b, 92c, 94c to the connected one(s) of the intake valves 22 or exhaust valves 24. In addition, the input rocker levers 504, 506, 508 can be controlled to selectively disconnect from the output rocker lever 502 so that no valve lift is provided during cylinder deactivation. The controlled connection and disconnection of output rocker 502 and input rockers 504, 506, and/or 508 can occur by engagement from output rocker 502 to input rockers 504, 506, and/or 508; by engagement from input rockers 504, 506, and/or 508 to output rocker 502; and combinations thereof.

[0087] A biasing mechanism includes brake biasing springs 524, 526 that are each in contact with respective ones of the input rocker levers 506, 508 and output rocker lever 502, and a standard biasing spring 522 in contact with input rocker lever 504 and output rocker lever 502 to bias the corresponding rollers 510, 512, 514 into direct or indirect contact with the respective camshaft lobes. Lash adjusters 530, 532, which can be mechanical or hydraulic, are connected the output rocker lever 502 and the corresponding ones of the intake valves 22 or exhaust valves 24.

[0088] The rocker system 500 includes a first valve lift switch 550 for selectively connecting and disconnecting first input rocker lever 504 to output rocker lever 502 to transfer motion from or prevent the transfer of motion from the associated camshaft lobe 92a, 94a to the connected ones of the intake and/or exhaust valves 22, 24. The rocker system 500 also includes a second valve lift switch 600 for selectively connecting and disconnecting input rocker levers 506, 508 to output rocker lever 502 to transfer motion or prevent the transfer of motion from the associated camshaft lobes 92b, 94b, 92c, 94c to the connected ones of the intake and/or exhaust valves 22, 24.

[0089] Referring further to FIGs. 20-22, first valve lift switch 550 is housed in a bore 552 that extends between output rocker lever 502 and first input rocker lever 504. First valve lift switch 550 includes a first valve lift pin assembly 554 that includes a first valve lift pin 556 comprising multiple shear pin parts 570, 572, 574 normally biased into contact with one another via spring 558 to an engaged position against an end base 518 such that first input rocker lever 504 is connected to output rocker lever 502, as shown in FIG. 20. In the engaged position, the valve lift pin 556 spans the joints 560, 562 between the rocker levers 502, 504, forming shear interfaces 560a, 562a at joints 560, 562. The engaged position of first switch 550 is used during operating conditions in which the standard or nominal lift for the intake or exhaust valves 22, 24 is desired from the camshaft lobes 92a, 94a.

[0090] In order to disconnect or decouple rocker levers 502, 504 from one another, hydraulic fluid pressure is supplied into bore 552 from rocker shaft 120 of the engine 12 via the hydraulic system of engine 12 through into a control volume 566 at an end of bore 552 opposite spring 558. The hydraulic fluid pressure in control volume 566 displaces shear pin parts 570, 572, 574 off of end base 518 toward the opposite end of bore 552, compressing spring 558, as shown in FIG. 21 and FIG. 22. In this condition, the end-to-end junctions of the shear pin parts 570, 572, 574 are moved into alignment with joints 560, 562. This alignment position removes the shear interfaces 560a, 562a since no part of first valve lift pin 556 spans the joints 560, 562. As a result, rotation of the first input rocker lever 504 is not transferred to output rocker lever 502, and the motion imparted by the camshaft lobes 92a, 94a is not transferred to the intake or exhaust valves 22, 24. The disengaged position for first valve lift switch 550 is used during operating conditions in which cylinder deactivation is desired, or during which an alternate lift profile from the second and third input rockers 506, 508 is desired from camshaft lobes 92b, 94b, 92c, 94c. [0091] Second valve lift switch 600 is housed in a bore 602 in output rocker lever 502, second input rocker lever 506, and third input rocker lever 508. Second valve lift switch 600 includes a second valve lift pin assembly 604 that includes a second valve lift pin 606 comprising multiple shear pin parts 620, 622, 624 in bore 602. Shear pin parts 620, 622, 624 are normally biased into end-to-end contact with one another via spring 608 and against an end base 618 in bore 602 to a disengaged position, as shown in FIGs. 20 and 21.

[0092] In the engaged position shown in FIG. 22, the second input rocker lever 506 and third input rocker lever 508 are connected to output rocker lever 502. In the engaged position, the shear pin parts 620, 622, 624 of shear pin 606 span the joints 610, 612 between the rocker levers 502, 506, 508, forming shear interfaces 610a, 612a at joints 610, 612. The engaged position of second valve lift switch 600 is used during operating conditions in which the alternative lift for the intake or exhaust valves 22, 24 is desired from the camshaft lobes 92b, 94b, 92c, 94c via the input rocker levers 506, 508. In order to connect or couple rocker levers 502, 506, 508 to one another, hydraulic fluid pressure is supplied into bore 602 from the rocker shaft 120 of engine 12 via the hydraulic system of engine 12 through opening 616, and into the control pressure space 614 of bore 602 at end base 618. The hydraulic fluid pressure displaces shear pin parts 620, 622, 624 off of end base 618, compressing spring 608 so that the shear pin parts span joints 610, 612, as shown in FIG. 22.

[0093] In the disengaged condition, the shear pin parts 620, 622, 624 are located within output rocker lever 502 and input rocker levers 506, 508 so that shear pin parts 620, 622, 624 do not span joints 610, 612. This disengaged position removes the shear interfaces 610a, 612a since no part of second valve lift pin 606 spans the joints 610, 612. As a result, rotation of the second and third input rocker levers 506, 508 is not transferred to output rocker lever 502, and the motion imparted by the camshaft lobes 92b, 94b, 92c, 94c is not transferred to the intake or exhaust valves 22, 24. The disengaged position for second valve lift switch 600 is used during operating conditions in which cylinder deactivation is desired, or during which a nominal or standard lift profile from the first input rocker lever 504 is desired from camshaft lobes 92a, 94a.

[0094] Referring to FIGs. 23-24, rocker system 500 is shown with multiple stop pins 580 engaged to each of the input rocker levers 504, 506, 508. Output rocker lever 502 includes stop member projections 582 that contact stop members 580 when the parts of bores 552, 602 are aligned with one another. Stop pins 580 are configured to prevent over-rotation of the output rocker lever 502 in the clockwise direction of FIG. 23. Stop pins 580 also prevent over-rotation of the input rocker levers 504, 506, 508 in the counterclockwise direction. This ensures the portions of bore 552 and/or bore 602 that house the various parts of valve lift pins 556, 606 are in alignment with one another along the base circle of the respective cam lobes even as the lash adjustment of the intake valves 22 and/or exhaust valves 24 varies. The aligned portions of bores 552, 602 allow smooth actuation of the valve lift pins 556, 606 to selectively engage input rockers 504, 506, 508 with output rocker 502.

[0095] Referring to FIGs. 25-28, another embodiment rocker system 700 is shown. Rocker system 700 can be similar to rocker systems 100, 300, 500 discussed above, and the discussion that follows is directed to further features of rocker system 700. One or more aspects or features of rocker systems 100, 300, 500 discussed above can be provided for rocker system 700, and vice versa.

[0096] Referring to FIGs. 25-27, rocker system 700 includes a first output rocker lever 702, a second output rocker lever 704, and a first input rocker lever 706, that are each rotatably mountable to an engine component 120, such as a rocker shaft. A retaining ring 121 can be provided to secure rocker levers 702, 704, 706 on rocker shaft 120. Second output rocker lever 704 includes a first roller 710 for direct or indirect contact with the corresponding camshaft lobe 92a, 94a. First input rocker lever 706 includes a second roller 712 for direct or indirect contact with the corresponding camshaft lobe 92b, 94b. If desired, one or more additional input rocker levers can be provided for direct or indirect contact with other camshaft lobes if additional valve lift functionality is desired.

[0097] The second output rocker lever 704 is controllable to selectively connect with the first output rocker lever 702 to transfer motion from the respective camshaft lobe(s) 92a, 94a to the connected one(s) of the intake valves 22 or exhaust valves 24. In addition, the second output rocker lever 704 and/or input rocker lever(s) 706 can be controlled to be connected to one another and disconnected from the first output rocker lever 702 so that an alternative valve lift can be provided to second output rocker lever 704 from input rocker lever 706. The connection and disconnection of output rocker levers 702, 704 and input rocker lever(s) 706 can occur by engagement from first output rocker lever 702 to rocker levers 704, 706; by engagement from second output rocker lever 704 to first output rocker lever 702 and to input rocker lever 706; by engagement from input rocker lever 706 to second output rocker lever 704; and combinations thereof.

[0098] A biasing mechanism includes biasing springs 724, 726 that are each in contact with output rocker lever 702 and respective ones of the output rocker lever 704 and input rocker lever 706 to bias the corresponding rollers 710, 712, into direct or indirect contact with the respective camshaft lobes. Lash adjusters 730, 732, which can be mechanical or hydraulic, are connected the output rocker levers 702, 704 and the corresponding ones of the intake valves 22 or exhaust valves 24.

[0099] The rocker system 700 includes a valve lift switch 750 that is controllable for selectively connecting and disconnecting first output rocker lever 702 from second output rocker input rocker 704, and simultaneously connect second output rocker lever 704 to input rocker lever 706 transfer motion from or prevent the transfer of motion from the associated camshaft lobes to the connected ones of the intake and/or exhaust valves 22, 24. The rocker system 700 may also include additional valve lift switches such as those disclosed herein that are controlled for selectively connecting and disconnecting additional input rocker levers for added functionality, such as cylinder deactivation, two-stroke braking, etc.

[0100] Referring further to FIG. 28, valve lift switch 750 is housed in a bore 752 that extends in and from first output rocker lever 702, second output rocker lever 704, and input rocker lever 706. Valve lift switch 750 includes a first valve lift pin assembly 754 that includes a first valve lift pin 756 comprising multiple shear pin parts 770, 772 normally biased by spring 758, 759 to connect first and second output rocker levers 702, 704 and disconnect input rocker lever 706, as shown in FIG. 28. In the engaged position, the valve lift pin 756 spans the joint 760 between the rocker levers 702, 704, forming shear interfaces 760a at joint 760. The engaged position of switch 750 is used during operating conditions in which the standard or nominal lift for the intake or exhaust valves 22, 24 is desired from the camshaft lobes 92a, 94a.

[0101] In order to disconnect or decouple output rocker levers 702, 704 from one another, hydraulic fluid pressure is supplied into bore 752 from rocker shaft 120 of the engine 12 via the hydraulic system of engine 12 through into a control volume 766 at an end of bore 752 opposite springs 758, 759. The hydraulic fluid pressure in control volume 766 displaces shear pin parts 770, 772 toward the opposite end of bore 752, compressing springs 758, 759. In this condition, the shear pin part 770 is moved out of first input rocker lever 702 into alignment with joint 760. This alignment position removes the shear interface 760a since no part of first valve lift pin 756 spans the joint 760. As a result, rotation of the second output rocker lever 704 is not transferred to first output rocker lever 702, and the motion imparted by the camshaft lobes 92a, 94a is not transferred to the intake or exhaust valves 22, 24.

[0102] Actuation of valve lift switch 750 also simultaneously connects input rocker lever 706 with second output rocker lever 704. Displacement of shear pin part 770 displaces shear pin part 772 so that shear pin part 770 spans joint 762 and shear pin part 772 spans joint 764, creating shear interfaces between rocker levers 704, 706 at joints 762, 764. This actuated position for valve lift switch 750 is used during operating conditions in which braking or other alternative valve lift is desired for the valve connected to second output rocker 704 an alternate camshaft lobe 92b, 94b, 92c, 94c via input rocker lever 706. Other embodiments contemplate the use of other input rockers and/or valve lift switches to connect other input rockers and/or to provide cylinder deactivation.

[0103] Referring to FIGs. 29-30, another embodiment rocker system 800 is shown. Rocker system 800 can be similar to rocker systems 100, 300, 500, 700 discussed above, and the discussion that follows is directed to further features of rocker system 800. One or more aspects or features of rocker systems 100, 300, 500, 700 discussed above can be provided for rocker system 800, and vice versa.

[0104] Rocker system 800 includes a first output rocker lever 802, a second output rocker lever 804, a first input rocker lever 806, and a second input rocker lever 808, that are each rotatably mountable to an engine component 120, such as a rocker shaft. First input rocker lever 806 includes a first roller 810 for direct or indirect contact with the corresponding camshaft lobe 92a, 94a. Second input rocker lever 808 includes a second roller 812 for direct or indirect contact with the corresponding camshaft lobe 92b, 94b. If desired, one or more additional input rocker levers can be provided for direct or indirect contact with other camshaft lobes if additional valve functionality is desired.

[0105] The first input rocker lever 806 is selectively connectable with the first and second output rocker levers 802, 804 to transfer motion from the respective camshaft lobe(s) 92a, 94a to the connected one(s) of the intake valves 22 or exhaust valves 24. In addition, the second input rocker lever 808 can be connected to second output rocker lever 804 so that an alternative valve lift can be provided to second output rocker lever 804 from second input rocker lever 808. The connection and disconnection of output rocker levers 802, 804 and input rocker levers 806, 808 can occur by engagement from the output rocker levers to the input rocker levers, from the input rocker levers to the output rocker levers, and combinations thereof.

[0106] A biasing mechanism includes biasing springs 824, 826, 828 that are each in contact with respective ones of the output rocker levers 802, 804 and the input rocker levers 806, 808 to bias the corresponding rollers 810, 812, into direct or indirect contact with the respective camshaft lobes. Lash adjusters 830, 832, which can be mechanical or hydraulic, are connected the output rocker levers 802, 804 and the corresponding ones of the intake valves 22 or exhaust valves 24. [0107] The rocker system 800 includes a first valve lift switch 850 that can be controlled for selectively connecting and disconnecting first output rocker lever 802 and second output rocker input rocker 804 with first input rocker lever 806. Similar to the valve lift switches discussed above, first valve lift switch 850 includes a valve lift pin assembly 854 including a valve lift pin 856 with multiple shear pin parts 858, 860, 862. In the engaged position, shear pin parts 860, 862 span joints 864, 866 at shear interfaces 864a, 866a to connect first input rocker lever 806 to output rocker levers 802, 804. Valve lift pin 856 can be hydraulically actuated to compress springs 852, 853 and align the end-to-end abutments of shear pin parts 858, 860, 862 with joints 864, 866 to decouple first input rocker lever 806 from output rocker levers 802, 804, such as for cylinder deactivation.

[0108] Rocker system 800 includes a second valve lift switch 870 to selectively connect second input rocker lever 808 to second output rocker lever 804 in order to provide an alternative valve lift profile from a different cam lobe. Second valve lift switch 870 includes a valve lift pin assembly 874 including first and second pin parts 876, 878 that are normally biased into second input rocker 808 with springs 880, 882. Hydraulic fluid pressure is used to actuate first and second pin parts 876, 878 away from one another to span joints 884, 886 between second input rocker lever 808 and second output rocker lever 804. The second input rocker lever 808 can be connected to second output rocker lever 804 during, for example, exhaust braking.

[0109] Referring to FIGs. 31-32, a number of exhaust rocker systems 900a, 900b (collectively and individually referred to as exhaust rocker systems 900) and intake rocker systems 990a, 990b (collectively and individually referred to as intake rocker systems 990) are shown along two cylinders 14 of an engine. The intake rocker system 990 includes a pair of output rocker levers 992 each connected to the intake valves with a cross-head 998. Intake rocker system 990 also includes two input rocker levers 994, 996 that are selectively connected and disconnected from the respective output rocker levers 992 to provide the desired intake valve lift profile.

[0110] Each exhaust rocker system 900 includes an output rocker lever 902 connected to a single exhaust valve 24 for each cylinder 14. Exhaust rocker system 900 also includes a first input rocker lever 904 and a second input rocker lever 906 that are selectively connected and disconnected from output rocker lever 902 to provide the desired valve lift.

[OHl] For example, as shown in FIG. 32, a first valve lift switch 920 is provided for selectively connecting and disconnecting output rocker lever 902 and first input rocker lever 904. Similar to the valve lift switches discussed above, first valve lift switch 920 includes a valve lift pin assembly 924 including a valve lift pin 926 with multiple shear pin parts 928, 930. In the normally engaged position, valve lift pin 926 is biased by spring 932 so that shear pin part 928 spans joint 934 to connect first input rocker lever 904 to output rocker lever 902. Valve lift pin 926 can be hydraulically actuated to compress spring 932 and align the end-to-end abutments of shear pin parts 928, 930 with joint 934 to decouple first input rocker lever 904 from output rocker lever 902, such as for cylinder deactivation.

[0112] Exhaust rocker system 900 includes a second valve lift switch 940 to selectively connect second input rocker lever 906 to output rocker lever 902 in order to provide an alternative valve lift profile from a different cam lobe. Second valve lift switch 940 includes a valve lift pin assembly 944 including first and second pin parts 946, 948 that are normally biased with spring 952 to align the end-to-end abutment of pin parts 946, 948 with joint 954. Hydraulic fluid pressure is used to actuate first and second pin parts 946, 948 to compress spring 952 and span joint 954 with first pin part 946 between second input rocker lever 906 and output rocker lever 902. The second input rocker lever 906 can be connected to output rocker lever 902 during, for example, exhaust braking.

[0113] Referring to FIG. 33, another embodiment rocker system 1000 is shown. Rocker system 1000 includes a first output rocker lever 1002 and a second output rocker lever 1004, each rotatable about an engine component 120, such as a rocker shaft. Any suitable engine component is contemplated about which rocker levers can be rotated. Each of the first and second output rocker levers 1002, 1004 includes mechanical lash adjusters 1006, 1008. In another embodiment, lash adjusters 1006, 1008 are hydraulic lash adjusters rather than mechanical lash adjusters. Rocker system 1000 also includes an input rocker lever 1010 rotatable about an engine component 120. Input rocker lever 1010 is functionally associated with the first and second output rocker levers 1002, 1004, and operates in two modes to impart a lift profile to the first and second output rocker levers 1002, 1004. As used herein, a lift profile may also include a partial lift profile.

[0114] In a first mode, the input rocker lever 1010 operates in either an activated or deactivated state. In the activated state the input rocker lever 1010 engages with the first and second output rocker levers 1002, 1004, causing rotational motion of the first and second output rocker levers 1002, 1004 with the cam lobe acting on roller 1020. Alternatively, the first and second output rocker lever 1002, 1004 engage the input rocker lever 1010. In the deactivated state, the input rocker lever 1010 disengages with the first and second output rocker levers 1002, 1004 and absorbs the motion of the cam lobe 1020 through lost motion devices 1012, 1014. Lost motion devices 1012, 1014 may include, for example, compressible bodies capable of exerting a reactionary forces, coil springs, spiral springs, wave springs or hydraulic cylinders. In the deactivated state of the first mode, the valve motions for the connected intake and exhaust valves 22, 24 can be shut-off.

[0115] In the second mode, the input rocker lever 1010 operates in either an activated or deactivated state. In the activated state, the input rocker lever 1010 engages with either the first or second output rocker lever 1002, 1004, causing rotational motion of the associated engaged rocker lever 1002, 1003. Alternatively, one of the first or second output rocker levers 1002, 1004 engages the input rocker lever 1010. The unassociated output rocker lever 1002, 1004 is disengaged, and the motion of the cam lobe is absorbed through the corresponding lost motion device 1012, 1014. In the deactivated state, the input rocker lever 1010 disengages with the first and second output rocker levers 1002, 1004 and absorbs the motion of the cam lobe through lost motion devices 1012, 1014. In the deactivated state of the second mode, the valve motions for the connected intake and/or exhaust valves 22, 24 can be shut-off.

[0116] Referring to FIG. 34, another embodiment rocker system 1100 is shown. Rocker system 1100 includes a single output rocker lever 1102 rotatable about an engine component 120. Output rocker lever 1102 is configured to impart motion on two intake valves 22 or two exhaust valves 24, and is configured with mechanical lash adjusters 1106, 1108. In another embodiment, lash adjusters 1106, 1108 are hydraulic lash adjusters rather than mechanical lash adjusters. Rocker system 1100 also includes an input rocker lever 1110 rotatable about an engine component 120. Input rocker lever 1110 imparts a lift profile to the output rocker lever 1102 via roller 1120 receiving motion from a cam lobe.

[0117] The input rocker lever 1110 can operate in either an activated or deactivated state. In the activated state, the input rocker lever 1110 engages with the output lever 1102, causing rotational motion of the output rocker lever 1102. Alternatively, the output rocker lever 1102 engages the input rocker lever 1110. In the deactivated state, the input rocker lever 1110 disengages with the output rocker lever 1102 and absorbs the motion of the cam lobe through a lost motion device 1112.

[0118] Referring to FIG. 35, another embodiment rocker system 1200 is shown. Rocker system 1200 is similar to rocker system 1000, and like components are designated with similar reference numerals. However, rocker system 1200 includes a second input rocker lever 1202 that is rotatable about an engine component 120 in response to motion imparted by a second cam lobe on cam roller 1206.

[0119] Second input rocker lever 1202 operates in two modes. In a first mode, the first input rocker lever 1010 is selectively engageable with both output rocker levers 1002, 1004. In an activated state of the second input rocker lever 1202 in the first mode, second input rocker lever 1202 and the associated output rocker lever 1002 are engaged with one another while first input rocker lever 1010 is deactivated, causing rotational motion of the associated output rocker lever 1002 only with second input rocker lever 1202. In the deactivated state of the second input rocker lever 1202, the second input rocker lever 1202 disengages with the associated output rocker lever 1002 and absorbs the motion of the cam lobe through lost motion device 1204. In the first mode, second input rocker lever 1202 can therefore be in an inversely activated/deactivated state with the first input lever 1010 relative to the engagement with both output rocker levers 1002, 1004. Also, in the first mode of second input rocker lever 1202, the second input rocker lever 1202 can be can be simultaneously deactivated with first input rocker lever 1010 from the corresponding one of the output rocker levers 1002, 1004, or in an inversely activated/deactivated state the first input rocker lever 1010.

[0120] In the second mode of second input rocker lever 1202, the first input rocker lever 1010 is controlled to be selectively engageable with only one of the output rocker levers 1002, 1004. In the activated state of the second input rocker lever 1202 in the second mode, the second input rocker lever 1202 engages with the associated output rocker lever 1002, causing rotational motion of the associated output rocker lever 1002. In the deactivated state of the second input rocker lever 1202, the second input lever 1202 disengages with the associated output rocker lever 1002 and absorbs the motion of the cam lobe through lost motion device 1204. In the second mode of the second input rocker lever 1202, second input rocker lever 1202 can be in a simultaneously activated state with the first input lever 1010 to engage different ones of input rocker levers 1002, 1004. Also, in the second mode of the second input rocker lever 1202, second input rocker lever 1202 and first input rocker lever 1010 can be simultaneously deactivated, or inversely deactivated from one another.

[0121] In the activated state of the second input rocker lever 1202 in the first and second modes, the second input rocker lever 1202 can impart at least one of normal lift event, braking lift event, late intake valve closing (LIVC), early intake valve closing (EIVC), late intake valve opening (LIVO), early intake valve opening (EIVO), early exhaust valve opening (EEVO), early exhaust valve closing (EEVC), late exhaust valve closing (LEVC), late exhaust valve opening (LEVO), internal exhaust gas recirculation (i-EGR) lift events, reduced lift, increased lift, early extended dwell, or late extended dwell on a second valve 22, 24 independently of the first valve 22, 24. [0122] Referring to FIG. 36, another embodiment rocker system 1300 is shown. Rocker system 1300 includes a combined input/output rocker lever 1302 rotatable about an engine component 120. Combined input/output rocker lever 1302 includes a lash adjuster 1306. Rocker lever assembly 1300 also includes a second output rocker lever 1304 rotatable about an engine component 120, and second output rocker lever 1304 includes a lash adjuster 1308.

[0123] The combined input/output rocker lever 1302, functionally associated with the second output rocker lever 1304, imparts a fixed lift profile onto a first valve and selectively imparts the same lift profile to the second output rocker lever 1304. The second output rocker lever 1304 operates in either an activated or deactivated state in association with the combined input/output rocker lever 1302. In the activated state, the combined input/output rocker lever 1302 and the second output rocker lever 1304 are engaged, causing rotational motion of the second output rocker lever 1304. In the deactivated state, the combined input/output rocker lever 1302 and the second output rocker lever 1304 are disengaged, and the motion of the cam lobe is absorbed through lost motion device 1312.

[0124] A second input rocker lever 1310, functionally associated with the second output rocker lever 1304, can impart a lift profile to second output rocker lever 1304. The second input rocker lever 1310 operates in an inversely activated/deactivated state to the combined input/output rocker lever 1302, and also can be in a simultaneously deactivated with combined input/output rocker lever 1302.

[0125] In the activated state of the second input rocker lever 1310, second input rocker lever 1310 engages with the second output rocker lever 1304, causing rotational motion of the second output rocker lever 1304. In the deactivated state, the second input rocker lever 1310 disengages with the second output rocker lever 1304 and absorbs the motion of the cam lobe through a lost motion device 1314. In the activated state, the second input rocker lever 1310 can impart at least one of normal lift event, braking lift event, LIVC, EIVC, LIVO, EIVO, EEVO, EEVC, LEVC, LEVO, i-EGR lift events, reduced lift, increased lift, early extended dwell or late extended dwell on a second valve independently of the first valve. [0126] Referring to FIG. 37, a rocker system 1400 is shown that is similar to rocker system 1100, and similarly includes a single output rocker lever 1402 rotatable about an engine component 120. Output rocker lever 1402 is configured to impart motion on two intake valves 22 or two exhaust valves 24, and is configured with lash adjusters 1406, 1408. Rocker system 1400 also includes a first input rocker lever 1410 and a second input rocker lever 1412, each rotatable about an engine component 120. Lost motion devices 1414, 1416 are associated with respective ones of the first and second input rocker levers 1410, 1412

[0127] Each of the first and second input rocker levers 1410, 1412 are functionally associated with the output rocker lever 1402 and imparts a lift profile to the output rocker lever 1402. The second input rocker lever 1412 operates in either an inversely activated state to the first input rocker lever 1410, and either in a simultaneously deactivated state or inversely deactivated state with first input rocker lever 1410. In the activated state, the second input rocker lever 1412 engages with the output rocker lever 1402, causing rotational motion of the output rocker lever 1402.

[0128] In the deactivated state, the second input rocker lever 1412 disengages with the output rocker lever 1402 and absorbs the motion of the cam lobe through lost motion device 1416. In the activated state, the second input rocker lever 1412 can impart at least one of braking lift event, LIVC, EIVC, LIVO, EIVO, EEVO, EEVC, LEVC, LEVO, i-EGR lift events, reduced lift, increased lift, early extended dwell or late extended dwell on two or more intake valves 22 or exhaust valves 24 simultaneously.

[0129] FIGs. 38-41 illustrate other arrangements of rockers systems. For example, in FIG. 38 rocker system 1500 is similar to rocker system 1400, but includes first and second output rocker levers 1502, 1504 that are selectively engageable to three input rocker levers 1510, 1512, 1514. In FIG. 39 rocker system 1600 includes a single combined input/output rocker lever 1602 that is selectively engageable to two input rocker levers 1610, 1612.

[0130] FIG. 40 illustrates a rocker system 1700 that includes a combined input/out rocker lever 1702, a second output rocker 1704, and two input rocker levers 1710, 1712. FIG. 41 illustrates a rocker system 1800 that includes a single output rocker lever 1802 that is selectively engageable to three input rocker levers 1810, 1812, 1814.

[0131] The rocker systems 100, 300, 500, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700 disclosed herein can be used in any type of valve train, including type II, type III, type IV, and/or type V valve trains. The rocker systems 100, 300, 500, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700 allow multiple modes of operation to be provided at the intake and/or exhaust valve for one or more cylinders 14 of engine 12 using a single hydraulic actuator. The modes of operation can include, for example, a standard lift profile, no lift for cylinder deactivation, and an alternate lift profile. The alternate lift profile can be to provide, for example, engine braking, such as four stroke compression braking or two stroke compression braking. An example two stoke compression braking valve lift profile for the intake and exhaust valves is shown in FIG. 3 with IV2 and EV2. Other alternative lift profiles are also contemplated other than those for compression braking, including LIVC, EIVC, LIVO, EIVO, EEVO, EEVC, LEVC, LEVO, i-EGR lift events, reduced lift, increased lift, early extended dwell or late extended dwell for one or more of the intake valves 22 and/or exhaust valves 24.

[0132] Valve actuation systems of any engine can be upgraded with using the rocker systems of the present disclosure. For example, the valve actuation system can be upgraded from a standard lift function for the intake and exhaust valves to include cylinder deactivation or four stroke compression braking. The valve actuation system can also be upgraded from a standard lift function for the intake and exhaust valves to include cylinder deactivation and four stroke compression braking. The valve actuation system can also be upgraded from a standard lift function for the intake and exhaust valves to include cylinder deactivation and two stroke compression braking.

[0133] During operation of the internal combustion engine system 10, the controller 80 can receive information from the various sensors listed above through I/O interface(s), process the received information using a processor based on an algorithm stored in a memory of the controller 80, and then send command signals to the various actuators through the I/O interface. For example, the controller 80 can receive information regarding cylinder deactivation condition, an engine braking request, a vehicle or engine speed request, a combustion condition, an aftertreatment temperature condition, and/or an engine load condition. The controller 80 is configured to process the conditions and/or requests, and then based on the control strategy, send one or more command signals to one or more actuators to provide cylinder deactivation and/or an alternate valve lift profile using the associated camshaft lobes and input rocker levers. [0134] The controller 80 can be configured to implement the disclosed cylinder deactivation and alternative valve lift strategies using VA system 90 incorporating the rocker systems disclosed herein. In one embodiment, the disclosed method and/or controller configuration include the controller 80 providing a cylinder deactivation command or an alternate valve lift command in response to a cylinder deactivation condition or an engine operating condition that is based on one or more signals from one or more of the plurality of sensors described above for internal combustion engine system 10. The cylinder deactivation and alternative valve lift commands control VA mechanism 90 to switch the camshaft lobes for input to provide the desired intake and exhaust valve closure or opening and closing lift profile and/or timing.

[0135] The control procedures implemented by the controller 80 can be executed by a processor of controller 80 executing program instructions (algorithms) stored in the memory of the controller 80. The descriptions herein can be implemented with internal combustion engine system 10. In certain embodiments, the internal combustion engine system 10 further includes a controller 80 structured or configured to perform certain operations to control internal combustion engine system 10 in achieving one or more target conditions. In certain embodiments, the controller forms a portion of a processing subsystem including one or more computing devices having memory, processing, and communication hardware. The controller may be a single device or a distributed device, and the functions of the controller 80 may be performed by hardware and/or by instructions encoded on a computer readable medium.

[0136] In certain embodiments, the controller 80 includes one or more modules structured to functionally execute the operations of the controller. The description herein including modules emphasizes the structural independence of the aspects of the controller, and illustrates one grouping of operations and responsibilities of the controller. Other groupings that execute similar overall operations are understood within the scope of the present application. Modules may be implemented in hardware and/or software on a non-transient computer readable storage medium, and modules may be distributed across various hardware or other computer components.

[0137] Certain operations described herein include operations to interpret or determine one or more parameters. Interpreting or determining, as utilized herein, includes receiving values by any method known in the art, including at least receiving values from a datalink or network communication, receiving an electronic signal (e.g. a voltage, frequency, current, or PWM signal) indicative of the value, receiving a software parameter indicative of the value, reading the value from a memory location on a non-transient computer readable storage medium, receiving the value as a run-time parameter by any means known in the art, and/or by receiving a value by which the interpreted or determined parameter can be calculated, and/or by referencing a default value that is interpreted or determined to be the parameter value.

[0138] Various aspects of the present disclosure are contemplated as described in the claims. In one aspect, a rocker system for an internal combustion engine is provided. The rocker system includes at least one input rocker lever rotatable about an engine component in response to motion received from at least one camshaft lobe of a camshaft and at least one output rocker lever rotatable about the engine component. The at least one output rocker lever is configured to control opening and closing of at least one exhaust valve or at least one intake valve associated with a cylinder of the internal combustion engine. The rocker system also includes at least one valve lift switch operable to connect the at least one input rocker lever and the at least one output rocker lever to one another for transferring motion from the at least one camshaft lobe to the at least one exhaust valve or the at least one intake valve, and to disconnect the at least one input rocker lever and the at least one output rocker lever from one another. The rocker system also includes at least one additional input rocker lever or output rocker lever connectable to the at least one output rocker lever with the at least one valve lift switch.

[0139] In an embodiment, the rocker system includes a lash adjuster that connects the at least one of the exhaust valve or the at least one intake valve to the output rocker lever.

[0140] In an embodiment, the at least one input rocker lever includes a first input rocker lever and a second input rocker lever that are each rotatable about the engine component in response to motion received from respective ones of a first camshaft lobe and a second camshaft lobe of the camshaft.

[0141] In a refinement of the above embodiment, the at least one valve lift switch is operable to connect each of the first and second input rocker levers to the at least one output rocker lever. In another refinement, the at least one valve lift switch includes a first valve lift switch for selectively connecting the first input rocker lever to the at least one output rocker lever and a second valve lift switch for selectively connecting the second input rocker lever to the at least one output rocker lever. [0142] In still a further refinement the first valve lift switch includes a first pin assembly housed in a first bore that extends between the at least one output rocker lever and the first input rocker lever. The first pin assembly includes a first valve lift pin movable in the first bore from a first position in which the first valve lift pin connects the at least one output rocker lever to the first input rocker lever so that the at least one output rocker lever and the first input rocker lever rotate about the engine component together to a second position in the first bore in which the first valve lift pin is housed in one of the at least one output rocker lever and the first input rocker lever so the first input rocker lever is disconnected from the at least one output rocker lever and rotation of the first input rocker lever is not transferred to the at least one output rocker lever. In addition, the second valve lift switch includes a second pin assembly housed in a second bore that extends between the at least one output rocker lever and the second input rocker lever. The second pin assembly includes a second valve lift pin movable in the second bore from a first position in which the second valve lift pin connects the at least one output rocker lever to the second input rocker lever so that the at least one output rocker lever and the second input rocker lever rotate about the engine component together to a second position in the second bore in which the second valve lift pin is housed in one of the at least one output rocker lever and the second input rocker lever so the second input rocker lever is disconnected from the at least one output rocker lever and rotation of the second input rocker lever about the engine component is not transferred to the at least one output rocker lever.

[0143] In a further refinement, in a cylinder deactivation mode of operation, the first valve lift pin and the second valve lift pin are each placed in the second positions in the first bore and the second bore, respectively, so that rotation of the first input rocker lever and rotation of the second input rocker lever about the engine component is not transferred to the at least one output rocker lever.

[0144] In a further refinement, in a standard lift mode of operation, the first valve lift pin is placed in the first position in the first bore and the second valve lift pin is placed in the second position in the second bore so that rotation of the first input rocker lever about the engine component is transferred to the at least one output rocker lever and rotation of the second input rocker lever about the engine component is not transferred to the at least one output rocker lever. [0145] In a further refinement, in an auxiliary lift mode of operation, at least the second valve lift pin is placed in the first position in the second bore so that rotation of the second input rocker lever about the engine component is transferred to the at least one output rocker lever.

[0146] In a further refinement, the first valve lift pin includes first and second shear pin parts in the first bore that are biased away from one another to the first position, and are movable via hydraulic fluid pressure from the first position to the second position. The valve lift pin also includes third and fourth shear pin parts in the second bore that are biased toward from one another to the second position, and are movable via hydraulic fluid pressure from the second position to the first position.

[0147] In a further refinement, the first valve lift pin includes first and second shear pin parts in abutting engagement with one another in the first bore that are biased to the first position, and are movable via hydraulic fluid pressure from the first position to the second position. The second valve lift pin in the second bore is biased to the second position, and is movable via hydraulic fluid pressure from the second position to the first position.

[0148] In an embodiment, the at least one input rocker lever includes a standard lift input rocker lever rotatable about the engine component in response to motion received from a first camshaft lobe of the camshaft, a first auxiliary lift input rocker lever rotatable about the engine component in response to motion received from a second camshaft lobe of the camshaft, and a second auxiliary lift input rocker lever rotatable about the engine component in response to motion received from a third camshaft lobe of the camshaft.

[0149] In a refinement of this embodiment, the at least one output rocker lever includes a rocker body with a first arm spaced from a second arm. The first and second arms are configured for placement around the engine component and form a space therebetween for receipt of the standard lift input rocker lever. The first auxiliary lift input rocker lever is positioned on the engine component on a side of the first arm opposite the standard lift input rocker lever, and the second auxiliary lift input rocker lever is positioned on the engine component on a side of the second arm opposite the standard lift input rocker lever.

[0150] In a refinement of the embodiment, each of the standard lift input rocker lever, the first auxiliary lift input rocker lever, and the second auxiliary lift input rocker levers include a roller in direct or indirect contact with the respective ones of the first, second and third camshaft lobes of the camshaft. [0151] In a further refinement, each of the standard lift input rocker lever, the first auxiliary lift input rocker lever, and the second auxiliary lift input rocker lever is engaged to respective ones of first, second and third biasing springs that contact the output rocker lever and bias the rollers into direct or indirect contact with the respective ones of the first, second and third camshaft lobes of the camshaft.

[0152] According to another aspect, a rocker system for an internal combustion engine is provided. The rocker system includes a first input rocker lever rotatable about an engine component in response to motion received from a first camshaft lobe of a camshaft, a second input rocker lever rotatable about an engine component in response to motion received from a second camshaft lobe of the camshaft, and at least one output rocker lever rotatable about the engine component. The at least one output rocker lever is configured to control opening and closing of at least one exhaust valve or at least one intake valve associated with a cylinder of the internal combustion engine. The rocker system also includes a first valve lift switch and a second valve lift switch. The first valve lift switch is operable to connect the first input rocker lever to the at least one output rocker lever to transfer motion from the first camshaft lobe to the at least one exhaust valve or the at least one intake valve. The second valve lift switch is operable to connect the second input rocker lever to the at least one output rocker lever to transfer motion from the second camshaft lobe to the at least one exhaust valve or the at least one intake valve. The first and second valve lift switches are operable to disconnect the respective first and second input rocker levers from the at least one output rocker lever so that motion from the first and second camshaft lobes is not transferred to the at least one output rocker lever.

[0153] In an embodiment, the first valve lift switch is housed in a first bore extending between the at least one output rocker lever and the first input rocker lever, and the second valve lift switch is housed in a second bore extending between the at least one output rocker lever and the second input rocker lever.

[0154] In an embodiment, the first valve lift switch and the second valve lift switch are each hydraulically controlled to connect and disconnect the corresponding one of the first input rocker lever and the second input rocker lever to the at least one output rocker lever.

[0155] In an embodiment, the rocker system includes a third input rocker lever rotatable about the engine component in response to motion received from a third camshaft lobe of the camshaft. The third input rocker lever is connectable to the at least one output rocker lever with the second switch to transfer motion from the third camshaft lobe to the at least one exhaust valve or the at least one intake valve. The third rocker lever is disconnectable from the at least one output rocker lever so that motion from the third camshaft lobe is not transferred to the at least one output rocker lever.

[0156] In an embodiment, the rocker system includes a second output rocker lever rotatable about the engine component. The second output rocker lever is configured to control opening and closing of at least one other exhaust valve or at least one other intake valve associated with a cylinder of the internal combustion engine. The first switch is operable to connect and disconnect the second output rocker lever from the at least one output rocker lever.

[0157] While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain exemplary embodiments have been shown and described. Those skilled in the art will appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

[0158] In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary.