Variable displacement engines including different cam lobe profiles

Abstract

The present application relates to variable displacement engines including cams with different cam lobe profiles, and provides methods and systems for engines including cams with different cam lobe profiles. In one example, cams of a first cam set actuate multiple deactivatable cylinder valves, and cams of a second cam set actuate multiple non-deactivatable cylinder valves. The cams of the first cam set have different cam profiles relative to the cams of the second cam set.

Description

Technical Field

[0001] The present description generally relates to methods and systems for an internal combustion engine including cams having different lobe profiles. Background Art

[0002] An internal combustion engine can be configured to operate with a variable number of activated or deactivated cylinders to increase fuel economy while optionally maintaining an overall exhaust mixture air-fuel ratio approximately stoichiometric. This operation may be referred to as VDE (variable displacement engine) operation. In some examples, a portion of the engine's cylinders may be disabled during selected conditions, where the selected conditions may be defined by parameters such as engine speed and / or load thresholds and various other operating conditions such as vehicle speed. The control system may enable and / or disable selected cylinders by adjusting a plurality of cylinder valve deactivators that affect the operation of the cylinders' intake and exhaust valves.

[0003] Each cylinder valve deactivator may be a rolling finger follower of a deactivatable valvetrain, wherein each rolling finger follower is switchable from an activated mode to a deactivated mode (and vice versa). During conditions in which the rolling finger follower is in the activated mode, the outer arm of the rolling finger follower is driven by rotation of a camshaft cam to move a poppet valve, wherein movement of the poppet valve controls the flow of gas into or out of the engine's combustion chamber. In the deactivated mode, the outer arm is not driven by the cam, so that the rotational motion of the cam is not transferred to the poppet valve, resulting in lost motion.

[0004] However, the rolling finger followers of a deactivatable valve assembly are typically produced with inherent nominal lash and lash maximum wear characteristics that are different from those of a non-deactivatable rolling finger follower. These characteristics may result in different lift amounts and / or different lift timings for the poppet valves driven by the deactivatable rolling finger followers. An example method for addressing these issues is shown by Hendriksma et al. in U.S. Patent 7,322,329. Therein, the valve deactivation roller hydraulic valve lifter assembly process includes correlating the leak test results of each lash adjuster with the residual lash test results to minimize the total length variation in the deactivatable roller hydraulic valve. Another example method is shown by Hicks in U.S. Patent 6,513,471. Therein, the timing of the exhaust cam driving the valve of the deactivatable cylinder is advanced relative to the timing of the exhaust cam driving the valve of the non-deactivatable cylinder. This results in the amount of overlap in the opening time of the valve of the deactivatable cylinder being approximately the same as the overlap of the valve of the non-deactivatable cylinder.

[0005] However, the inventors herein have recognized potential issues with such systems. As one example, reducing the length variation between valve deactivation roller hydraulic valve lifters can reduce the amount of variation in lift and / or lift timing of the lift valves driven by the lifters, but this does not address the difference in lift and / or lift timing between deactivatable lift valves and non-deactivatable lift valves. As another example, advancing the timing of the cam associated with a deactivatable valve relative to the cam associated with a non-deactivatable valve can increase engine control complexity and reduce engine efficiency. Summary of the Invention

[0006] In one example, the above problem can be solved by a system comprising: a camshaft including a first plurality of cams and a second plurality of cams, each cam of the first plurality of cams having a first cam lobe profile and each cam of the second plurality of cams having a different second cam lobe profile; a plurality of deactivatable cylinder valves actuated by the first plurality of cams; and a plurality of non-deactivatable cylinder valves actuated by the second plurality of cams. In this manner, each of the deactivatable cylinder valves and the non-deactivatable cylinder valves can have the same valve opening rate and valve closing rate, as well as the same amount of valve overlap.

[0007] As an example, each cam of the first plurality of cams and the second plurality of cams includes an outer surface that tapers from a base segment of the cam to a nose segment of the cam. The outer surface of each cam of the first plurality of cams has a different curvature than the corresponding outer surface of each cam of the second plurality of cams. By configuring the cams in this manner, the second plurality of cams actuates the valves of the non-deactivatable cylinders with the same timing and lift as the valves of the deactivatable cylinders actuated by the first plurality of cams. By actuating the valves with the same timing and lift, combustion stability of an engine including the cams and cylinders can be increased.

[0008] It should be understood that the above summary is provided to introduce some concepts further described in the detailed description in a simplified form. It is not intended to identify key or essential features of the claimed subject matter, the scope of which is defined solely by the appended claims. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A variable displacement engine including a combustion chamber having intake and / or exhaust valves actuated via a camshaft is schematically shown.

[0010] Figure 2A series of engines is shown including a first engine having non-deactivatable cylinder valves driven by a cam having a first cam lobe profile and a second engine having deactivatable cylinder valves driven by a cam having a second cam lobe profile and non-deactivatable cylinder valves driven by a cam having a third cam lobe profile.

[0011] Figure 3 An intake camshaft and an exhaust camshaft of a variable displacement engine are shown, where each camshaft includes a first set of cams having a first cam lobe profile and a second set of cams having a second cam lobe profile.

[0012] Figure 4 Description of the cam lobe profile relative to a cam for an engine that does not include deactivatable cylinder valves Figure 3 A first cam lobe profile and a second cam lobe profile of a cam are shown.

[0013] Figure 5 A graph is shown illustrating the valve lift profiles of the intake and exhaust valves of a first engine including only non-deactivatable intake valves and non-deactivatable exhaust valves, in contrast to the valve lift profiles of the deactivatable intake and deactivatable exhaust valves of a second engine including both deactivatable and non-deactivatable intake and exhaust valves.

[0014] Figure 6 A diagram illustrating valve lift profiles for a non-deactivatable intake valve and a non-deactivatable exhaust valve relative to a second engine is shown. Figure 5 A graph of the valve lift profiles of the deactivatable intake valves and deactivatable exhaust valves of a second engine.

[0015] Figures 3 and 4 Shown to scale, but other relative dimensions may be used if desired. DETAILED DESCRIPTION

[0016] The following description relates to systems and methods for engines including cams having different cam profiles. Figure 1 The engine shown in FIG) includes a plurality of cylinders, each cylinder having at least one intake valve and at least one exhaust valve. Figure 2 As shown, the engine may be the second engine of a family of engines, wherein the first engine of the family of engines includes only non-deactivatable cylinders, and wherein the second engine includes both non-deactivatable cylinders and deactivatable cylinders. Figure 3As shown, the intake valves and exhaust valves are driven by a plurality of cams via the rotation of the camshaft of the engine. Each camshaft of the second engine includes a first set of cams having a first cam lobe profile and a second set of cams having a second cam lobe profile. The valves driven by the first set of cams can be switched from the start mode to the deactivation mode (and vice versa), and the valves driven by the second set of cams cannot be switched between the start mode and the deactivation mode. Figure 4 As shown, the first cam lobe profile may have a different outer surface curvature relative to the second cam lobe profile. Figure 6 As shown, the difference in curvature of the first set of cams relative to the curvature of the second set of cams results in a reduction in the amount by which the valve lift profiles of the deactivatable valves of the second engine differ relative to the valve lift profiles of the non-deactivatable valves of the second engine. Figure 5 As shown, the difference in valve lift profiles between the deactivatable valves of the second engine and the non-deactivatable valves of the first engine, which includes only non-deactivatable cylinders, is greatly reduced. By reducing the difference in valve lift profiles between the deactivatable valves and the non-deactivatable valves of the second engine via the first and second cam groups, combustion stability and fuel efficiency of the engine can be increased, and noise, vibration, and harshness (NVH) of the engine can be reduced, especially at idle speeds.

[0017] Figure 1 An example of a combustion chamber or cylinder of internal combustion engine 10 is depicted. Engine 10 may be controlled at least partially by a control system including controller 12 and by input from a vehicle operator 130 via an input device 132. In this example, input device 132 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP. Cylinder 14 of engine 10 (also referred to herein as a "combustion chamber") may include combustion chamber walls 136 with a piston 138 positioned therein. Cylinder 14 is covered by a cylinder head 157. Piston 138 may be coupled to a crankshaft 140 so that reciprocating motion of the piston is translated into rotational motion of the crankshaft. Crankshaft 140 may be coupled to at least one drive wheel of a passenger vehicle via a transmission system. Furthermore, a starter motor (not shown) may be coupled to crankshaft 140 via a flywheel to enable a starting operation of engine 10.

[0018] Cylinder 14 may receive intake air via a series of intake passages 142, 144, and 146. Intake passage 146 may also communicate with other cylinders of engine 10 in addition to cylinder 14. In some examples, one or more of the intake passages may include a boosting device such as a turbocharger or supercharger. For example, Figure 1Engine 10 is shown configured with a turbocharger including a compressor 174 arranged between intake passages 142 and 144, and an exhaust turbine 176 arranged along exhaust passage 148. Where the boosting device is configured as a turbocharger, compressor 174 may be at least partially powered by exhaust turbine 176 via shaft 180. However, in other examples, such as where engine 10 is provided with a supercharger, exhaust turbine 176 may optionally be omitted, where compressor 174 may be powered by mechanical input from a motor or the engine. A throttle 162 including a throttle plate 164 may be provided along the intake passage of the engine for varying the flow rate and / or pressure of intake air provided to the engine cylinders. For example, throttle 162 may be configured as Figure 1 It is shown positioned downstream of compressor 174 , but alternatively may be provided upstream of compressor 174 .

[0019] Exhaust passage 148 may also receive exhaust gas from other cylinders of engine 10 in addition to cylinder 14. Exhaust gas sensor 128 is shown coupled to exhaust passage 148 upstream of emission control device 178. For example, sensor 128 may be selected from various suitable sensors for providing an indication of exhaust air-fuel ratio, such as a linear oxygen sensor or UEGO (Universal or Wide Range Exhaust Gas Oxygen), a two-state oxygen sensor or EGO (as depicted), a HEGO (Heated EGO), a NOx, HC, or CO sensor. Emission control device 178 may be a three-way catalyst (TWC), a NOx trap, various other emission control devices, or combinations thereof.

[0020] Each cylinder of engine 10 includes one or more intake valves and one or more exhaust valves. For example, cylinder 14 is shown including at least one intake poppet valve 150 and at least one exhaust poppet valve 156 located at an upper region of cylinder 14. In some examples, each cylinder of engine 10, including cylinder 14, may include at least two intake poppet valves and at least two exhaust poppet valves located at an upper region of the cylinder.

[0021] exist Figure 1 In the example of FIG, intake valve 150 and exhaust valve 156 are actuated (eg, opened and closed) via respective cam actuation systems 153 and 154. Cam actuation systems 153 and 154 each include one or more cams mounted on one or more camshafts (similar to Figure 214 and may include one or more additional intake and / or exhaust valves for cylinder 14. For example, cylinder 14 may include one or more additional intake valves controlled via electric valve actuation and one or more additional exhaust valves controlled via electric valve actuation.

[0022] Cylinder 14 may have a compression ratio, which is the ratio of volumes when piston 138 is at bottom center to when it is at top center. In one example, the compression ratio is in the range of 9:1 to 10:1. However, in some examples using different fuels, the compression ratio may be increased. This may occur, for example, when using a higher octane fuel or a fuel with a higher latent enthalpy of vaporization. The compression ratio may also be increased if direct injection is used due to its effect on engine knock.

[0023] In some examples, each cylinder of engine 10 may include a spark plug 192 housed in cylinder head 157 for initiating combustion. In select operating modes, ignition system 190 can provide an ignition spark to combustion chamber 14 via spark plug 192 in response to spark advance signal SA from controller 12. However, in some embodiments, spark plug 192 may be omitted, such as where engine 10 may initiate combustion by auto-ignition or by injection of fuel, as may be the case with some diesel engines.

[0024] In some examples, each cylinder of engine 10 may be configured with one or more fuel injectors for providing fuel thereto. As a non-limiting example, cylinder 14 is shown as including two fuel injectors 166 and 170. Fuel injectors 166 and 170 may be configured to deliver fuel received from fuel system 8. As shown in FIG. Figure 2 and Figure 3 As illustrated, fuel system 8 may include one or more fuel tanks, fuel pumps, and fuel rails. Fuel injector 166 is shown coupled directly to cylinder 14 for injecting fuel directly therein in proportion to the pulse width of signal FPW-1 received from controller 12 via electronic driver 168. In this manner, fuel injector 166 provides what is known as direct injection of fuel (hereinafter referred to as "DI") into combustion cylinder 14. Although Figure 1Injector 166 is shown positioned to the side of cylinder 14, but alternatively, it may be located on top of the piston, such as near spark plug 192. Due to the lower volatility of some alcohol-based fuels, such a location may improve mixing and combustion when the engine is operated on alcohol-based fuels. Alternatively, the injector may be located on top and near the intake valve to improve mixing. Fuel may be delivered to fuel injector 166 from a fuel tank of fuel system 8 via a high-pressure fuel pump and a fuel rail. The fuel tank may also have a pressure transducer that provides a signal to controller 12.

[0025] Fuel injector 170 is shown arranged in intake passage 146, rather than in cylinder 14, in a configuration that provides what is known as port injection of fuel (hereafter referred to as "PFI") into the intake port upstream of cylinder 14. Fuel injector 170 may inject fuel received from fuel system 8 in proportion to the pulse width of signal FPW-2 received from controller 12 via electronic driver 171. Note that a single driver 168 or 171 may be used for both fuel injection systems, or multiple drivers may be used as depicted, such as driver 168 for fuel injector 166 and driver 171 for fuel injector 170.

[0026] In an alternative example, each of fuel injectors 166 and 170 may be configured as a direct fuel injector for injecting fuel directly into cylinder 14. In yet another example, each of fuel injectors 166 and 170 may be configured as a port fuel injector for injecting fuel upstream of intake valve 150. In other examples, cylinder 14 may include only a single fuel injector that is configured to receive different fuels from the fuel system in varying relative amounts as a fuel mixture and further configured to inject the fuel mixture directly into the cylinder as a direct fuel injector or to inject the fuel mixture upstream of the intake valve as a port fuel injector. Thus, it should be understood that the fuel system described herein should not be limited to the specific fuel injector configurations described herein by way of example.

[0027] During a single cycle of the cylinder, fuel may be delivered to the cylinder via both injectors. For example, each injector may deliver a portion of the total fuel injection for combustion in cylinder 14. Furthermore, as described below, the distribution and / or relative amount of fuel delivered from each injector may vary with operating conditions (such as engine load, knock, and exhaust temperature). Port-injected fuel may be delivered during an open intake valve event, a closed intake valve event (e.g., substantially prior to the intake stroke), and during both open and closed intake valve operations. Similarly, for example, direct-injected fuel may be delivered during the intake stroke, partially during the preceding exhaust stroke, during the intake stroke, and partially during the compression stroke. Thus, even for a single combustion event, the injected fuel may be injected from the port and direct injectors at different timings. Furthermore, for a single combustion event, multiple injections of the delivered fuel may be performed per cycle. Multiple injections may be performed during the compression stroke, the intake stroke, or any suitable combination thereof.

[0028] Fuel injectors 166 and 170 may have different characteristics, such as differences in size. For example, one injector may have a larger spray orifice than the other. Other differences include, but are not limited to, different spray angles, different operating temperatures, different directional targets, different injection timings, different injection characteristics, different locations, etc. Furthermore, different effects may be achieved depending on the distribution ratio of the injected fuel between injectors 170 and 166.

[0029] The fuel tanks in the fuel system 8 can hold fuels of different fuel types, such as fuels with different fuel qualities and different fuel compositions. The differences can include different alcohol contents, different water contents, different octane numbers, different heats of vaporization, different fuel blends and / or combinations thereof. An example of a fuel with different heats of vaporization can include gasoline as a first fuel type with a lower heat of vaporization, and ethanol as a second fuel type with a larger heat of vaporization. In another example, the engine can use gasoline as the first fuel type, and an alcohol such as E85 (which contains approximately 85% ethanol and 15% gasoline) or M85 (which contains approximately 85% methanol and 15% gasoline) containing a fuel blend as the second fuel type. Other feasible substances include water, methanol, a mixture of alcohol and water, a mixture of water and methanol, a mixture of alcohol, etc.

[0030] In another example, the two fuels may be alcohol blends having different alcohol compositions, where the first fuel type may be a gasoline alcohol blend with a lower alcohol concentration, such as E10 (which contains approximately 10% ethanol), and the second fuel type may be a gasoline alcohol blend with a higher alcohol concentration, such as E85 (which contains approximately 85% ethanol). Furthermore, the first and second fuels may also differ in other fuel quality aspects, such as differences in temperature, viscosity, octane rating, etc. Furthermore, the fuel characteristics of one or both fuel tanks may change frequently, for example, due to daily variations in tank refilling.

[0031] In some examples, vehicle 5 may be a hybrid vehicle having multiple torque sources available to one or more wheels 55. In other examples, vehicle 5 is a conventional vehicle having only an engine or an electric vehicle having only one or more electric motors. In the illustrated example, vehicle 5 includes engine 10 and electric motor 52. Electric motor 52 may be a motor or a motor / generator. When one or more clutches are engaged, crankshaft 140 of engine 10 and electric motor 52 are connected to wheels 55 via transmission 54. In the depicted example, first clutch 56 is disposed between crankshaft 140 and electric motor 52, and second clutch 97 is disposed between electric motor 52 and transmission 54. Controller 12 may send signals to the actuators of each clutch (e.g., first clutch 56 and / or second clutch 97) to engage or disengage the clutches, thereby connecting or disconnecting crankshaft 140 from electric motor 52 and components connected thereto, and / or connecting or disconnecting electric motor 52 from transmission 54 and components connected thereto. Transmission 54 may be a gearbox, a planetary gear system, or another type of transmission. The powertrain can be configured in various ways to include parallel, series, or series-parallel hybrid vehicles.

[0032] The electric motor 52 receives power from the traction battery 58 to provide torque to the wheels 55. The electric motor 52 may also operate as a generator to provide power to the rechargeable battery 58, such as during braking operations.

[0033] As mentioned above, Figure 1 Only one cylinder of multi-cylinder engine 10 is shown. Thus, each cylinder may similarly include its own set of intake / exhaust valves, (one or more) fuel injectors, spark plugs, etc. It should be appreciated that engine 10 may include any suitable number of cylinders, including 2, 3, 4, 5, 6, 8, 10, 12, or more. Furthermore, each of these cylinders may include a reference cylinder 14 represented by Figure 1 Some or all of the various components described and depicted.

[0034] Engine 10 is a variable displacement engine, and cylinder 14 may be one of a plurality of deactivatable cylinders or a non-deactivatable cylinder of engine 10. For example, one or more valves (e.g., intake valve 150 and / or exhaust valve 156) of cylinder 14 may be adjusted from an activated mode to a deactivated mode (and vice versa) by controller 12. For example, cylinder 14 may be a deactivatable cylinder, wherein intake valve 150 and exhaust valve 156 are each coupled to a corresponding deactivatable valve assembly. In some examples, in response to a signal transmitted by controller 12 to the deactivatable valve assembly, the deactivatable valve assembly may adjust the operating mode of its corresponding coupled valve. Intake valve 150 is shown coupled to deactivatable valve assembly 151, and exhaust valve 156 is shown coupled to deactivatable valve assembly 152.

[0035] In one example, controller 12 may transmit an electrical signal to deactivatable valve assembly 151 to adjust the operating mode of intake valve 150 from an activated mode to a deactivated mode (or vice versa), and / or controller 12 may transmit an electrical signal to deactivatable valve assembly 152 to adjust the operating mode of exhaust valve 156 from an activated mode to a deactivated mode (or vice versa). In another example, each of the deactivatable valve assemblies (e.g., deactivatable valve assembly 151 and deactivatable valve assembly 152) may include a rocker arm coupled to a hydraulic lash adjuster. For example, deactivatable valve assembly 151 may include a hydraulic lash adjuster configured to reduce the clearance (e.g., the amount of lash) between the rocker arm and an intake cam of cam actuation system 153. Adjusting the pressure of the oil flowing into the hydraulic lash adjuster and / or the rocker arm may adjust the hydraulic lash adjuster and / or the rocker arm (respectively) from an activated mode to a deactivated mode (and vice versa).

[0036] In one example, in a startup mode, a rocker arm of a deactivatable valve assembly 151 coupled to an intake valve 150 is pressed into engagement with an intake cam of a cam actuation system 153 (e.g., pressed into engagement by a hydraulic lash adjuster), such that rotational motion of the intake cam of the cam actuation system 153 (e.g., rotational motion caused by rotation of a camshaft coupled to the intake cam of the cam actuation system 153 by engine 10) is translated into pivotal motion of the rocker arm, and the pivotal motion of the rocker arm is translated into linear motion of the intake valve 150. The linear motion of the intake valve 150 enables intake air to flow through the intake passage 146 and into the cylinder 14. For example, as the intake valve 150 moves toward the cylinder 14 (e.g., toward an open position), intake air flow around the intake valve 150 from the intake passage 146 and into the cylinder 14 may increase. As intake valve 150 moves away from cylinder 14 (e.g., toward a closed position), intake air flow around intake valve 150 from intake passage 146 and into cylinder 14 may decrease. In this way, movement of intake valve 150 provides cylinder 14 with intake air for combustion within cylinder 14. Similarly, in the starting mode, movement of exhaust valve 156 (e.g., via deactivatable valve assembly 152) causes the combusted fuel / air mixture to be expelled from cylinder 14 into exhaust passage 148.

[0037] However, in the deactivated mode, the rocker arm coupled to intake valve 150 is not pressed into engagement with the intake cam of cam actuation system 153 (e.g., not pressed into engagement by a hydraulic lash adjuster). Thus, rotational motion of the intake cam of cam actuation system 153 is not translated into pivotal motion of the rocker arm, and intake valve 150 does not move from a closed position toward an open position. During operating conditions in which intake valve 150 is in the deactivated mode, intake air does not flow into cylinder 14 (e.g., via intake passage 146). Similarly, during operating conditions in which exhaust valve 156 is in the deactivated mode, combustion gases are not exhausted from cylinder 14 (e.g., via exhaust passage 148). By deactivating both intake valve 150 and exhaust valve 156, fuel / air combustion within cylinder 14 can be prevented for a period of time (e.g., one or more complete cycles of engine 10). Additionally, during operating conditions where both intake valve 150 and exhaust valve 156 are in the deactivated mode, controller 12 may reduce the amount of fuel provided to cylinder 14 (e.g., via electrical signals transmitted to fuel injector 170 and / or fuel injector 166) and / or may reduce the amount of spark produced by spark plug 192 positioned within cylinder 14.

[0038] While operation of cylinder 14 is adjusted via deactivatable valve assemblies 151 and 152 as described above, in some examples (such as Figure 2In the examples shown and described below, operation of one or more cylinders of engine 10 may not be adjusted via the deactivatable valve assemblies. For example, engine 10 may include four cylinders (e.g., cylinder 14), where operation of a first pair of cylinders is adjusted via the deactivatable valve assemblies, and operation of a second pair of cylinders is not adjusted via the deactivatable valve assemblies.

[0039] In the above examples, transmitting the electrical signal to the deactivatable valve assembly via the controller may include transmitting the electrical signal to one or more hydraulic fluid valves fluidically coupled to corresponding hydraulic lash adjusters and / or rocker arms to adjust the hydraulic fluid valves to a fully closed position, a fully open position, or a plurality of positions between the fully closed position and the fully open position. In some examples, moving the one or more hydraulic fluid valves to an open position may increase the pressure of the oil at the hydraulic lash adjusters and / or rocker arms to operate the cylinder valves (e.g., intake valve 150 and exhaust valve 156) in the deactivated mode, and moving the hydraulic fluid valves to a closed position may not increase the pressure of the oil at the hydraulic lash adjusters and / or rocker arms to operate the cylinder valves in the activated mode.

[0040] Although operation of the intake valve 150 is described above as an example, the exhaust valve 156 can be operated in a similar manner (eg, where the operating mode of the exhaust valve 156 is adjusted via the deactivatable valve assembly 152 ).

[0041] The controller 12 Figure 1 Various sensors receive signals and use Figure 1 The controller 12 may control various actuators of the inlet valve 150 to adjust engine operation based on received signals and instructions stored in the memory of the controller. For example, adjusting the intake valve 150 from an activated mode to a deactivated mode may include adjusting an actuator of the intake valve 150 (e.g., the deactivatable valve assembly 151) to adjust the amount of movement of the intake valve 150 relative to the cylinder 14. For example, as described above, the controller 12 may transmit an electrical signal to a hydraulic fluid valve of the deactivatable valve assembly 151 (where the deactivatable valve assembly 151 is coupled to the intake valve 150) to move the hydraulic fluid valve of the deactivatable valve assembly 151 from a closed position to an open position. Moving the hydraulic fluid valve of the deactivatable valve assembly 151 to the open position may increase the pressure of the hydraulic fluid (e.g., oil) at the hydraulic lash adjuster and / or rocker arm of the deactivatable valve assembly 151. The increased pressure causes the rocker arm to disengage from the intake valve 150, thereby adjusting the intake valve to the deactivated mode. Similarly, controller 12 may transmit an electrical signal to the hydraulic fluid valve of deactivatable valve assembly 151 to move the hydraulic fluid valve to an open position and thereby adjust intake valve 150 to the activated mode.

[0042] Adjusting the rocker arm between the activated mode and the deactivated mode may adjust one or more corresponding cylinders of the engine from the activated mode to the deactivated mode (and vice versa).

[0043] The controller 12 Figure 1 10 is shown as a microcomputer including a microprocessor unit 106, input / output ports 108, an electronic storage medium for executable programs and calibration values (shown in this particular example as a non-transitory read-only memory chip 110 for storing executable instructions), a random access memory 112, a fail-safe memory 114, and a data bus. In addition to those signals previously discussed, controller 12 may also receive various signals from sensors coupled to engine 10, including: a sensed mass air flow (MAF) measurement from a mass air flow sensor 122; an engine coolant temperature (ECT) from a temperature sensor 116 coupled to a cooling sleeve 118; a profile ignition pickup signal (PIP) from a Hall effect sensor 120 (or other type) coupled to a crankshaft 140; a throttle position (TP) from a throttle position sensor; and an absolute manifold pressure signal (MAP) from sensor 124. Controller 12 may generate an engine speed signal, RPM, based on signal PIP. Manifold pressure signal MAP from a manifold pressure sensor may be used to provide an indication of vacuum, or pressure, in the intake manifold.Controller 12 may infer engine temperature based on engine coolant temperature.

[0044] Figure 2 An engine line (e.g., a series of engines) 205 is schematically shown including a first engine 201 and a second engine 203. The first engine 201 and the second engine 203 each include a plurality of identical components. Each identical component included in the first engine 201 and the second engine 203 may be labeled similarly.

[0045] The first engine 201 and the second engine 203 each include the same engine block 200. The engine block 200 forms a plurality of cylinders 204, and the cylinders 204 are connected by a cylinder head (such as Figure 1 The cylinder head 157 shown and described above is covered. Figure 2 In the example shown, engine block 200 includes eight cylinders 204 positioned in a V-shaped arrangement (e.g., with a first cylinder bank 216 positioned opposite a second cylinder bank 218 across a centerline 265 of engine block 200, with first cylinder bank 216 and second cylinder bank 218 each including four cylinders 204). In other examples, engine block 200 may include only a single cylinder bank and / or a different number of cylinders (e.g., three, four, six, twelve, etc.).

[0046] Each of the first engine 201 and the second engine 203 includes a plurality of camshafts adapted to actuate the intake and exhaust valves of the cylinders 204. Specifically, the cylinders 204 of the first cylinder bank 216 include intake valves actuated by the first intake camshaft 206 and exhaust valves actuated by the first exhaust camshaft 208, and the cylinders 204 of the second cylinder bank 218 include intake valves actuated by the second intake camshaft 212 and exhaust valves actuated by the second exhaust camshaft 214. The first intake camshaft 206, the first exhaust camshaft 208, the second intake camshaft 212, and the second exhaust camshaft 214 of the first engine 201 are identical to the first intake camshaft 206, the first exhaust camshaft 208, the second intake camshaft 212, and the second exhaust camshaft 214 of the second engine 203, respectively.

[0047] Although the first engine 201 and the second engine 203 each include the same camshaft, cylinders, cylinder banks, and engine blocks as described above, the first engine 201 and the second engine 203 each have different cam configurations, intake valve assembly configurations, and exhaust valve assembly configurations relative to each other. For example, each cylinder 204 of the first engine 201 may receive air flow through a corresponding intake valve assembly 260 from among the plurality of identical intake valve assemblies, and combusted air / fuel (e.g., exhaust gas) may flow out of each cylinder 204 of the first engine 201 through a corresponding exhaust valve assembly from among the plurality of identical exhaust valve assemblies 261.

[0048] Each intake valve assembly 260 of the first engine 201 is coupled to a corresponding cam of a plurality of identical intake cams 220, and each exhaust valve assembly 261 of the first engine 201 is coupled to a corresponding cam of a plurality of identical exhaust cams 221. Each intake cam 220 of the first engine 201 is identical to each other intake cam 220 of the first engine 201, and each exhaust cam 221 of the first engine 201 is identical to each other exhaust cam 221. For example, each of the intake cams 220 of the first engine 201 has the same shape and size (e.g., the same cam lobe profile, which may be referred to herein as a first intake cam lobe profile or a conventional intake cam lobe profile) as each other intake cam 220 of the first engine 201. Similarly, each of the exhaust cams 221 of the first engine 201 has the same shape and size (e.g., the same cam lobe profile, which may be referred to herein as a first exhaust cam lobe profile or a conventional exhaust cam lobe profile) as each other exhaust cam 221 of the first engine 201.

[0049] Each intake valve assembly 260 of the first engine 201 is identical to each other intake valve assembly 260 of the first engine 201, and each exhaust valve assembly 261 of the first engine 201 is identical to each other exhaust valve assembly 261 of the first engine 201. The intake valve assemblies 260 each include a non-deactivatable intake valve that can be driven by a non-deactivatable rocker arm coupled to a non-deactivatable hydraulic lash adjuster. The exhaust valve assemblies 261 each include a non-deactivatable exhaust valve that can be driven by a rocker arm coupled to a non-deactivatable hydraulic lash adjuster. As referred to herein, a non-deactivatable intake valve refers to an intake valve that is not adjustable from a startup mode (e.g., a mode in which the intake valve opens and closes to allow intake air to flow into the cylinder in response to rotation of a cam that engages the intake valve via a non-deactivatable rocker arm and a non-deactivatable hydraulic lash adjuster) to a deactivatable mode (e.g., a mode in which the intake valve does not open and remains in a closed position during a full rotation of the cam so that intake air does not flow into the cylinder via the intake valve). Similarly, a non-deactivatable exhaust valve refers to an exhaust valve that is not adjustable from a startup mode (e.g., a mode in which the exhaust valve opens and closes to allow exhaust air to flow out of the cylinder in response to rotation of a cam that engages the exhaust valve via a non-deactivatable rocker arm and a non-deactivatable hydraulic lash adjuster) to a deactivatable mode (e.g., a mode in which the exhaust valve does not open and remains in a closed position during a full rotation of the cam so that exhaust air does not flow out of the cylinder via the exhaust valve). A non-deactivatable hydraulic lash adjuster is one that is not adjustable from an activated mode (e.g., a mode in which the lash adjuster converts the rotational motion of the cam into pivotal motion of the rocker arm) to a deactivated mode (e.g., a mode in which the rotational motion of the cam is not converted into pivotal motion of the rocker arm). Similarly, a non-deactivatable rocker arm is one that is not adjustable from an activated mode (e.g., a mode in which the rotational motion of the cam is converted into pivotal motion of the rocker arm) to a deactivated mode (e.g., a mode in which the rotational motion of the cam is not converted into pivotal motion of the rocker arm).

[0050] Cylinders that are configured to receive intake air only via non-deactivatable intake valves and to exhaust combustion gases (e.g., burned fuel / air) only via non-deactivatable exhaust valves may be referred to herein as non-deactivatable cylinders. As an example, each cylinder 204 of the first engine 201 is a non-deactivatable cylinder (e.g., each intake valve assembly 260 coupled to the cylinder 204 includes a non-deactivatable intake valve, and each exhaust valve assembly 261 coupled to the cylinder 204 includes a non-deactivatable exhaust valve).

[0051] However, the second engine 203 includes a first plurality of cylinders that cannot be deactivated and a second plurality of cylinders that can be deactivated. Specifically, each cylinder 204 of the second engine 203 that cannot be deactivated is coupled to a corresponding intake valve assembly 260 including a non-deactivatable intake valve and a corresponding exhaust valve assembly 261 including a non-deactivatable exhaust valve. For example, Figure 2 As shown, outer cylinders 270 of the second engine 203 (eg, cylinders 204 positioned at opposite ends of the first and second cylinder banks 216 and 218 in the direction of the centerline 265 ) are non-deactivatable cylinders.

[0052] Each intake valve assembly 260 of the non-deactivatable cylinders of the second engine 203 is driven by rotation of one of the intake cams 230, and each exhaust valve assembly 261 of the non-deactivatable cylinders of the second engine 203 is driven by rotation of one of the exhaust cams 231. For example, the non-deactivatable cylinders of the first cylinder bank 216 of the second engine 203 (e.g., the outer cylinders 270) include intake valve assemblies 260 driven by rotation of the intake cams 230 coupled to the intake camshaft 206, and exhaust valve assemblies 261 driven by rotation of the exhaust cams 231 coupled to the exhaust camshaft 208. The non-deactivatable cylinders of the second cylinder bank 218 of the second engine 203 similarly include intake valve assemblies 260 driven by rotation of the intake cams 230 coupled to the intake camshaft 212, and exhaust valve assemblies 261 driven by rotation of the exhaust cams 231 coupled to the exhaust camshaft 214. Each intake cam 230 driving the intake valve assembly of the non-deactivatable cylinder is identical in shape and size, and each exhaust cam 231 driving the exhaust valve assembly of the non-deactivatable cylinder is identical in shape and size. For example, each intake cam 230 includes the same intake cam lobe profile (which may be referred to herein as the second intake cam lobe profile), and each exhaust cam 231 includes the same exhaust cam lobe profile (which may be referred to herein as the second exhaust cam lobe profile).

[0053] The second plurality of cylinders (eg, deactivatable cylinders) includes an innermost cylinder 272 positioned between the outer cylinders 270 of the first cylinder bank 216 and the outer cylinders 270 of the second cylinder bank 218 in the direction of the centerline 265. Figure 2In the example shown, the deactivatable cylinder is the innermost cylinder 272, but in other examples, the second engine 203 may include a different arrangement of deactivatable cylinders relative to non-deactivatable cylinders (e.g., wherein the deactivatable and non-deactivatable cylinders are positioned in an alternating arrangement, wherein the outer cylinders 270 are deactivatable and the innermost cylinders 272 are non-deactivatable, etc.). In one example, the outer cylinders 270 of the first cylinder bank 216 may be deactivatable, while the innermost cylinders 272 may be non-deactivatable, and the outer cylinders 270 of the second cylinder bank 218 may be non-deactivatable, while the innermost cylinders 272 of the second cylinder bank 218 may be deactivatable. Other examples of relative arrangements of deactivatable and non-deactivatable cylinders are possible. Each of the deactivatable cylinders is coupled to a corresponding intake valve assembly 262 including a deactivatable intake valve and a corresponding exhaust valve assembly 263 including a deactivatable exhaust valve.

[0054] As referred to herein, a deactivatable intake valve refers to an intake valve that is adjustable from a startup mode (e.g., a mode in which the intake valve opens and closes to allow intake air to flow into the cylinder in response to rotation of a cam that engages the intake valve via a rocker arm and a hydraulic lash adjuster) to a deactivation mode (e.g., a mode in which the intake valve does not open and remains in a closed position during a full rotation of the cam so that intake air does not flow into the cylinder via the intake valve). Similarly, a deactivatable exhaust valve refers to an exhaust valve that is adjustable from a startup mode (e.g., a mode in which the exhaust valve opens and closes to allow exhaust air to flow out of the cylinder in response to rotation of a cam that engages the exhaust valve via a rocker arm and a hydraulic lash adjuster) to a deactivation mode (e.g., a mode in which the exhaust valve does not open and remains in a closed position during a full rotation of the cam so that exhaust air does not flow out of the cylinder via the exhaust valve). A deactivatable hydraulic lash adjuster refers to a lash adjuster that is adjustable from an activated mode (e.g., a mode in which the lash adjuster converts the rotational motion of the cam into pivotal motion of the rocker arm) to a deactivated mode (e.g., a mode in which the rotational motion of the cam is not converted into pivotal motion of the rocker arm). A deactivatable rocker arm refers to a rocker arm that is adjustable from an activated mode (e.g., a mode in which the rotational motion of the cam is converted into pivotal motion of the rocker arm) to a deactivated mode (e.g., a mode in which the rotational motion of the cam is not converted into pivotal motion of the rocker arm).

[0055] In some examples, in response to the above reference Figure 1The controller 12 of the illustrated engine 10 may transmit electrical signals to the intake valve assembly 262 and the exhaust valve assembly 263, and the deactivatable intake valves and the deactivatable exhaust valves may be adjusted from an activated mode to a deactivated mode (and vice versa). For example, the controller may transmit electrical signals to one or more hydraulic fluid valves of the intake valve assembly 262 to adjust the oil pressure at the corresponding deactivatable hydraulic lash adjusters and / or deactivatable rocker arms of the intake valve assembly 262, and adjusting the oil pressure may adjust the intake valve assembly 262 from an activated mode to a deactivated mode (or vice versa). While the intake valve assembly 262 is described above as an example, the exhaust valve assembly 263 may be adjusted from an activated mode to a deactivated mode (and vice versa) in a similar manner (e.g., in response to the controller adjusting the oil pressure at the corresponding deactivatable hydraulic lash adjusters and / or deactivatable rocker arms of the exhaust valve assembly 263).

[0056] Each intake valve assembly 262 of the deactivatable cylinder is driven by rotation of one of the intake cams 240, and each exhaust valve assembly 263 of the deactivatable cylinder is driven by rotation of one of the exhaust cams 241. For example, the deactivatable cylinders of the first cylinder bank 216 of the second engine 203 (e.g., the innermost cylinder 272) include intake valve assemblies 262 driven by rotation of the intake cam 240 coupled to the intake camshaft 206, and exhaust valve assemblies 263 driven by rotation of the exhaust cam 241 coupled to the exhaust camshaft 208. The deactivatable cylinders of the second cylinder bank 218 of the second engine 203 similarly include intake valve assemblies 262 driven by rotation of the intake cam 240 coupled to the intake camshaft 212, and exhaust valve assemblies 263 driven by rotation of the exhaust cam 241 coupled to the exhaust camshaft 214. Each intake cam 240 driving the intake valve assembly of the deactivatable cylinder is identical in shape and size, and each exhaust cam 241 driving the exhaust valve assembly of the deactivatable cylinder is identical in shape and size. For example, each intake cam 240 includes the same intake cam lobe profile (which may be referred to herein as the third intake cam lobe profile), and each exhaust cam 241 includes the same exhaust cam lobe profile (which may be referred to herein as the third exhaust cam lobe profile).

[0057] As described above, the intake valve assemblies 260 of the first engine 201 are each driven by an intake cam 220, and each intake cam 220 has the same size and shape (e.g., each intake cam 220 has a first intake cam lobe profile). The exhaust valve assemblies 261 of the first engine 201 are each driven by an exhaust cam 221, and each exhaust cam 221 has the same size and shape (e.g., each exhaust cam 221 has a first exhaust cam lobe profile). Because each cylinder 204 of the first engine 201 includes the same intake valve assembly 260, the same exhaust valve assembly 261, intake cams 220 of the same size and shape, and exhaust valves 221 of the same size and shape, each cylinder 204 of the first engine 201 has the same amount of intake valve overlap and exhaust valve overlap relative to each other cylinder 204 of the first engine 201 for each single complete combustion cycle (e.g., the cylinder's intake stroke, compression stroke, power stroke, and exhaust stroke). However, as described above, each cylinder 204 of the first engine 201 is a non-deactivatable cylinder. Therefore, none of the cylinders 204 of the first engine 201 can be adjusted to a deactivation mode. For example, the controller of the first engine 201 may not send an electrical signal to the valve assemblies (e.g., the intake valve assembly 260 and / or the exhaust valve assembly 261) of the first engine 201 in order to deactivate one or more of the cylinders 204 of the first engine 201 (e.g., to prevent combustion of air / fuel within one or more cylinders, such as by closing an intake valve of the intake valve assembly 260 and / or an exhaust valve of the exhaust valve assembly 261).

[0058] However, the second engine 203 includes a deactivatable cylinder (e.g., innermost cylinder 272) and a non-deactivatable cylinder (e.g., outer cylinder 270), and the intake valve assembly 260 and exhaust valve assembly 261 of the non-deactivatable cylinder are different from the intake valve assembly 262 and exhaust valve assembly 263 of the deactivatable cylinder. As described above, the intake valve assembly 262 each includes a deactivatable intake valve, and the exhaust valve assembly 263 each includes a deactivatable exhaust valve. In one example, as described above, the deactivatable intake valve in each intake valve assembly 262 can be adjusted from an activation mode to a deactivation mode (and vice versa) by adjusting the oil pressure at the corresponding deactivatable hydraulic lash adjuster and / or deactivatable rocker arm coupled to the deactivatable intake valve, and the deactivatable exhaust valve in each exhaust valve assembly 263 can be adjusted from an activation mode to a deactivation mode (and vice versa) by adjusting the oil pressure at the corresponding deactivatable hydraulic lash adjuster and / or deactivatable rocker arm coupled to the deactivatable exhaust valve.

[0059] Intake valve assembly 262 and exhaust valve assembly 263 may include different components (e.g., deactivatable rocker arms and deactivatable hydraulic lash adjusters with different internal oil passages, pins, springs, bearings, etc.) relative to non-deactivatable intake valve assembly 260 and non-deactivatable exhaust valve assembly 261, which enables intake valve assembly 262 and exhaust valve assembly 263 to be adjusted from an activated mode to a deactivated mode. However, the different components of intake valve assembly 262 and exhaust valve assembly 263 may result in deactivatable intake valve assembly 262 and deactivatable exhaust valve assembly 263 having different operating characteristics relative to non-deactivatable intake valve assembly 260 and non-deactivatable exhaust valve assembly 261.

[0060] In one example, the intake valve assembly 262 and the exhaust valve assembly 263 may each include a deactivatable rocker arm having a clearance (e.g., a gap) positioned within the body of the deactivatable rocker arm, and the clearance may cause the rollers of the rocker arm to engage the corresponding cam differently than the rollers of the rocker arms of the non-deactivatable valve assembly. For example, the intake valve assembly 262 may include a deactivatable rocker arm having rollers that engage the intake cam 240 of the intake camshaft 206. The clearance within the body of each deactivatable rocker arm of the intake valve assembly 262 may cause the rollers of each deactivatable rocker arm to press against the corresponding engaged intake cam 240 with a first amount of force. However, the rollers of the non-deactivatable rocker arms of the intake valve assembly 260 of the second engine 203 may press against their corresponding engaged intake cam 230 with a second amount of force, where the second amount of force is different from the first amount of force.

[0061] The amount of engagement of the roller of the deactivatable rocker arm with the intake cam 240 is different relative to the amount of engagement of the roller of the non-deactivatable rocker arm with the intake cam 230, and the amount of engagement of the roller of the deactivatable rocker arm with the exhaust cam 241 is different relative to the amount of engagement of the roller of the non-deactivatable rocker arm with the exhaust cam 231. The shape and / or size of the intake cam 240 (e.g., the cam having the third intake cam lobe profile) is different from the shape and / or size of the intake cam 230 (e.g., the cam having the second intake cam lobe profile), and the shape and / or size of the exhaust cam 241 (e.g., the cam having the third exhaust cam lobe profile) is different from the shape and / or size of the exhaust cam 231 (e.g., the cam having the second exhaust cam lobe profile). Therefore, the amount of overlap between the intake valve driven by the intake cam 240 and the exhaust valve driven by the exhaust cam 241 (e.g., the valve of a deactivatable cylinder) is the same as the amount of overlap between the intake valve driven by the intake cam 230 of the second engine 203 and the exhaust valve driven by the exhaust cam 231 of the second engine 203 (e.g., the valve of a non-deactivatable cylinder of the second engine 203). The overlap of the intake and exhaust valves as described above refers to the amount of valve lift of the intake and exhaust valves during the duration that both the intake and exhaust valves are in the open position, which duration occurs during a single combustion cycle of the cylinder to which the intake and exhaust valves are each coupled.

[0062] By configuring the intake cam 240 with the third intake cam lobe profile and the exhaust cam 241 with the third exhaust cam lobe profile, the performance and / or durability of the intake valve assembly 262, the exhaust valve assembly 263, the intake cam 240, and / or the exhaust cam 241 may be increased. For example, engaging the intake cam with the first intake cam lobe profile or the second intake cam lobe profile with the intake valve assembly 262 of a deactivatable cylinder of the second engine 203 and engaging the exhaust cam with the first exhaust cam lobe profile or the second exhaust cam lobe profile with the exhaust valve assembly 263 of a deactivatable cylinder of the second engine 203 may result in increased noise, vibration, and / or harshness (NVH) during operation of the second engine 203. The increased NVH results from the differences in the components of the intake and exhaust valve assemblies 262 and 263 (e.g., rocker arms having a body with a void positioned therein) relative to the components of the intake and exhaust valve assemblies 260 and 261 (as described above). However, by combining an intake cam having a third intake cam lobe profile (e.g., intake cam 240) with the intake valve assemblies 262 of the deactivatable cylinders of the second engine 203 (e.g., Figure 2 ) and engages an exhaust cam having a third exhaust cam lobe profile (e.g., exhaust cam 241) with an exhaust valve assembly 263 (e.g., exhaust valve assembly 263) of a deactivatable cylinder of the second engine 203. Figure 2Engagement of the intake cam 240, the exhaust cam 241, the intake valve assembly 262 and / or the exhaust valve assembly 263 may reduce degradation.

[0063] Because the third intake cam lobe profile (e.g., the shape of the intake cam 240) is different from the first intake cam lobe profile (e.g., the shape of the intake cam 220 of the first engine 201), and because the third exhaust cam lobe profile (e.g., the shape of the exhaust cam 241) is different from the first exhaust cam lobe profile (e.g., the shape of the exhaust cam 221 of the first engine 201), the amount of valve overlap of the deactivatable cylinders of the second engine 203 is different from the amount of valve overlap of the non-deactivatable cylinders of the first engine 201. In order to configure each cylinder of the second engine 203 to have the same amount of valve overlap relative to every other cylinder of the second engine 203 (e.g., the same amount of overlap as a deactivatable cylinder having an intake valve actuated by the intake cam 240 and an exhaust valve actuated by the exhaust cam 241), the intake valves of the non-deactivatable cylinders of the second engine 203 (e.g., the outer cylinders 270) are actuated by the intake cam 230 having a second intake cam lobe profile, and the exhaust valves of the non-deactivatable cylinders of the second engine 203 are actuated by the exhaust cam 231 having a second exhaust cam lobe profile. The second intake cam lobe profile is different from the first intake cam lobe profile of the intake cam 220 of the first engine 201, and the second exhaust cam lobe profile is different from the first exhaust cam lobe profile of the exhaust cam 221 of the first engine 201. In addition, because the intake valve assembly 260 and the exhaust valve assembly 261 of the non-deactivatable cylinder of the second engine 203 include different components having different operating characteristics (as described above) relative to the intake valve assembly 262 and the exhaust valve assembly 263 of the deactivatable cylinder of the second engine 203, the second intake cam lobe profile is different from the third intake cam lobe profile, and the second exhaust cam lobe profile is different from the third exhaust cam lobe profile, thereby enabling the valves (e.g., intake valves and exhaust valves) of the non-deactivatable cylinder of the second engine 203 to have the same amount of overlap as the valves of the deactivatable cylinder of the second engine 203.

[0064] By configuring the intake and exhaust cams of second engine 203 in this manner, the intake and exhaust valves of each deactivatable and non-deactivatable cylinder of second engine 203 have the same amount of overlap, resulting in increased combustion stability (particularly during operating conditions where the engine is operated with each cylinder in the start mode). For example, during engine idling, each cylinder can be in the start mode, and because the valve overlap for each cylinder is the same (e.g., due to intake cam 230 having the second intake cam lobe profile, exhaust cam 231 having the second exhaust cam lobe profile, intake cam 240 having the third intake cam lobe profile, and exhaust cam 241 having the third exhaust cam lobe profile), the difference in the amount of gas (e.g., unburned intake air and / or burned air / fuel) remaining within each cylinder after each combustion cycle can be reduced. For example, the amount of gas residing in one of the deactivatable cylinders immediately following a combustion cycle of the deactivatable cylinder may be the same as the amount of gas residing in one of the non-deactivatable cylinders immediately following a combustion cycle of the non-deactivatable cylinder. By configuring each cylinder (e.g., a deactivatable cylinder and a non-deactivatable cylinder) to have the same amount of residual gas as described above (e.g., by configuring each cylinder to have the same amount of valve overlap), the torque balance of each cylinder may be increased.

[0065] Reference below Figure 4 An example of a first intake cam lobe profile, a second intake cam lobe profile, and a third intake cam lobe profile is described. As described below, a first exhaust cam lobe profile, a second exhaust cam lobe profile, and a third exhaust cam lobe profile may have a similar relative configuration. Figures 5 and 6 Example valve lift amounts corresponding to each cam lobe profile (eg, an intake cam lobe profile and an exhaust cam lobe profile) are described.

[0066] Figure 3 Shows something like Figure 2 The first camshaft 302 and the second camshaft 322 of the second engine 203 shown and described above are shown. For example, the first camshaft 302 is similar to the first intake camshaft 206 of the first cylinder bank 216, and the second camshaft 322 is similar to the first exhaust camshaft 208 of the first cylinder bank 216, wherein the first intake camshaft 206, the first exhaust camshaft 208, and the first cylinder bank 216 are referred to above. Figure 2The first camshaft 302 includes a first plurality of cams 303 (which may be referred to herein as a first cam set) and a second plurality of cams 312 (which may be referred to herein as a second camshaft), and the second camshaft 322 includes a third plurality of cams 334 (which may be referred to herein as a third cam set) and a fourth plurality of cams 332 (which may be referred to herein as a fourth cam set). For illustrative purposes, the first camshaft 302 includes a first plurality of cams 303 (which may be referred to herein as a first cam set) and a second plurality of cams 312 (which may be referred to herein as a second camshaft). Figure 3 However, in this article reference Figures 2 to 3 Examples of relative shapes and sizes of cams are described by Figure 4 shown and described further below.

[0067] The first cam group 303 includes intake cams 304 and 310, and the third cam group 334 includes exhaust cams 324 and 330. The intake cams 304 and 310 may be similar to Figure 2 The intake cam 230 shown in FIG. 1 may have a second intake cam lobe profile as described above. The exhaust cams 324 and 330 may be similar to Figure 2 The exhaust cam 231 shown in FIG. 2 may have a second exhaust cam lobe profile as described above. The second cam group 312 includes intake cams 306 and 308, and the fourth cam group 332 includes exhaust cams 326 and 328. The intake cams 306 and 308 may be similar to Figure 2 The intake cam 240 shown may include a third intake cam lobe profile as described above. The exhaust cams 326 and 328 may be similar to Figure 2 The exhaust cam 241 is shown and may include a third exhaust cam lobe profile as described above. The intake cams 304 and 310 of the first cam set 303 actuate non-deactivatable intake valves coupled to non-deactivatable cylinders of the engine (e.g., similar to the non-deactivatable intake valves of the intake valve assembly 260 of the second engine 203 described above), and the intake cams 306 and 308 of the second cam set 312 actuate deactivatable intake valves coupled to deactivatable cylinders of the engine (e.g., similar to the deactivatable intake valves of the intake valve assembly 262). The exhaust cams 324 and 330 of the third cam group 334 drive the non-deactivatable exhaust valves of the non-deactivatable cylinders coupled to the engine (e.g., similar to the non-deactivatable exhaust valves of the exhaust valve assembly 261 of the second engine 203 as described above), and the exhaust cams 326 and 328 of the fourth cam group 332 drive the deactivatable exhaust valves of the deactivatable cylinders coupled to the engine (e.g., similar to the deactivatable exhaust valves of the exhaust valve assembly 263 of the second engine 203 as described above).

[0068] Each camshaft is driven by a corresponding pulley, and each pulley is driven by the engine's crankshaft. For example, first camshaft 302 is driven by rotation of first pulley 316 about rotational axis 320 (e.g., in rotational direction 342), and second camshaft 322 is driven by rotation of second pulley 338 about rotational axis 336 (e.g., in rotational direction 344), wherein first pulley 316 and second pulley 338 are each driven by the engine's crankshaft via first belt 318 and second belt 340, respectively. In some examples, first pulley 316 and second pulley 338 can be coupled together (e.g., via a belt or chain) such that first pulley 316 and second pulley 338 rotate at the same rate. In other examples, first pulley 316 and second pulley 338 can rotate at different rates.

[0069] As referenced above Figure 2 As described, the amount of valve overlap of the cylinder valves (e.g., intake and exhaust valves) driven by rotation of the first camshaft 302 and the second camshaft 322 is the same for each cylinder of the engine. For example, the amount of valve overlap of the non-deactivatable intake valve driven by the intake cam 304 of the first camshaft 302 and the non-deactivatable exhaust valve driven by the exhaust cam 324 of the second camshaft 322 is the same as the amount of valve overlap of the deactivatable intake valve driven by the intake cam 306 of the first camshaft 302 and the deactivatable exhaust valve driven by the exhaust cam 326 of the second camshaft 322 (e.g., as described above, this is because the intake cam 304 has the second intake cam lobe profile and the exhaust cam 324 has the second exhaust cam lobe profile, and the intake cam 306 has the third intake cam lobe profile and the exhaust cam 326 has the third exhaust cam lobe profile). By configuring the engine to have the same amount of valve overlap for each cylinder, the combustion stability of the engine is increased, particularly during operating conditions where each cylinder is in a start-up mode. In some examples, the combustion stability of the engine is similar to that described above with reference to Figure 2 The combustion stability of the first engine 201 described is comparable, wherein the engine including the first camshaft 302 and the second camshaft 322 also includes deactivatable cylinders that can be adjusted to a deactivation mode to increase fuel efficiency. In this way, engine performance can be increased and engine noise, vibration, and harshness can be reduced.

[0070] Figure 4 The first cam 401, the second cam 403, and the third cam 405 of the engine are shown positioned to align with each other along a common rotational axis 432 to illustrate the relative differences between the cam lobe profiles of each cam. In one example, the first cam 401 may be similar to Figure 2 The intake cam 220 shown schematically and described above, the second cam 403 may be similar to Figure 2The intake cam 230 is schematically shown and Figure 3 The intake cams 304 and 310 are shown, and the third cam 405 may be similar to Figure 2 The intake cam 240 and Figure 3 The intake cams 306 and 308 shown and described above. The first cam 401 includes a first intake cam lobe profile 400, the second cam 403 includes a second intake cam lobe profile 402, and the third cam 405 includes a third intake cam lobe profile 404. In some examples, the rotational axis 432 can be the rotational axis of the camshaft (e.g., as described above with reference to FIG. Figure 3 The rotation axis 320 or the rotation axis 336 described above). Figures 2 to 3 Example cam lobe profiles similar to the first intake cam lobe profile 400, the second intake cam lobe profile 402, and the third intake cam lobe profile 404 are depicted. The first intake cam lobe profile 400 (similar to Figure 1 The first intake cam lobe profile of the cam 220 shown and described above) is shown in shortest dashed lines, and the second intake cam lobe profile 402 (similar to Figure 2 The cam 230 shown and the above reference Figure 3 The second intake cam lobe profile of the cams 304 and 310 depicted in FIG. 1 is shown in longer dashed lines, and the third intake cam lobe profile 404 (similar to FIG. Figure 2 The third intake cam lobe profile of the illustrated cam 240 and the cams 306 and 308 described above is shown in solid lines. As referred to herein, "cam lobe profile" and "lobe profile" refer to the shape and size of an outer surface (e.g., outer contour) of a cam adapted to engage a component of a valve assembly (e.g., a roller of a rocker arm), wherein rotation of the cam may cause the outer surface to press against the component of the valve assembly to open and / or close the valves of the valve assembly.

[0071] Each of the first cam 401, the second cam 403 and the third cam 405 is Figure 4 , for relative comparison of each cam lobe profile (e.g., first intake cam lobe profile 400, second intake cam lobe profile 402, and third intake cam lobe profile 404, respectively). In other examples, first cam 401, second cam 403, and third cam 405 may be compared to Figure 4 However, in each embodiment, the first intake cam lobe profile 400, the second intake cam lobe profile 402, and the third intake cam lobe profile 404 are each different relative to each other (e.g., the first cam 401, the second cam 403, and the third cam 405 are each shaped differently and have different outer profiles relative to each other).

[0072] As described above, each cam (e.g., first cam 401, second cam 403, and third cam 405) is aligned with each other cam along rotational axis 432 for comparison of each intake cam lobe profile. Rotational axis 432 extends through the center of each cam's base circle segment 418 in a direction perpendicular to base circle segment 418 (e.g., orthogonal to the plane in which the entire base circle segment 418 lies). Each cam includes a nose positioned radially away from rotational axis 432 relative to each other cam. For example, first cam 401 includes nose 423, second cam 403 includes nose 421, and third cam 405 includes nose 420. Each nose is positioned at a different distance from rotational axis 432 than each other nose. For example, nose 420 of third cam 405 is positioned away from rotation axis 432 by a first length 416, nose 421 of second cam 403 is positioned away from rotation axis 432 by a second length that is less than first length 416, and nose 423 of first cam 401 is positioned away from rotation axis 432 by a third length that is less than the second length. First length 416 is the length from rotation axis 432 to axis 422, the second length is the length from rotation axis 432 to axis 450, and the third length is the length from rotation axis to axis 451, wherein axis 422 is arranged tangentially to and located along nose 420, axis 450 is arranged tangentially to and located along nose 421, and axis 451 is arranged tangentially to and located along nose 423.

[0073] As described above, the nose 423 of the first cam 401, the nose 421 of the second cam 403, and the nose 420 of the third cam 405 are each positioned at different lengths away from the rotation axis 432. For example, the nose 420 of the third cam 405 is positioned at the first length 416 away from the rotation axis 432, and the nose 421 of the second cam 403 and the nose 423 of the first cam 401 are each positioned at a length less than the first length 416 away from the rotation axis 432. Figure 2As described above, the deactivatable intake valve assembly and the deactivatable exhaust valve assembly (e.g., intake valve assembly 262 and exhaust valve assembly 263 described above) may each include a deactivatable rocker arm having a clearance (e.g., a gap) positioned within the body of the deactivatable rocker arm. In the example described herein, the clearance of the deactivatable rocker arm of the deactivatable intake valve assembly may result in a different amount of engagement of the roller of the deactivatable rocker arm with the corresponding cam (e.g., the third cam 405) than the amount of engagement of the roller of the non-deactivatable rocker arm of the non-deactivatable valve assembly with the corresponding cam (e.g., the first cam 401). Due to the clearance of the deactivatable rocker arm and the increased length (e.g., first length 416) of the nose 420 of the third cam 405 from the axis of rotation 432 (e.g., relative to the length of the nose 421 of the second cam 403 from the axis of rotation 432, and the length of the nose 423 of the first cam 401 from the axis of rotation 432), the lift height of the valve (e.g., an intake valve or an exhaust valve) driven by the deactivatable rocker arm engaged with the third cam 405 in the fully open position may be different from the lift height of the valve driven by the non-deactivatable rocker arm engaged with the first cam 401 in the fully open position.

[0074] As described above, the nose 450 of the second cam 403 is positioned away from the rotational axis 432 by a second length, wherein the second length is less than the first length 416. In this configuration, although the nose 421 of the second cam 403 and the nose 420 of the third cam 405 are each positioned away from the rotational axis by different amounts (e.g., lengths), due to the presence of clearance for the deactivatable rocker arm engaged with the third cam 405, the valve driven by the second cam 403 can have the same amount of valve lift in the fully open position as the valve driven by the third cam 405. In other words, the nose 421 of the second cam 403 and the nose 420 of the third cam 405 can each be positioned away from the rotational axis 432 by different amounts, thereby compensating for the clearance for the deactivatable rocker arm engaged with the third cam 405 and providing the same lift height for the valves driven by the second cam 403 and the third cam 405.

[0075] The nose of each cam is the portion of each cam that is located farthest from the axis of rotation 432 (e.g., the portion of each lobe of each cam). Figure 2 During operating conditions in which the rollers of a rocker arm of the intake valve assembly 260 (shown in FIG. 1 and described above) are engaged, the nose 420 presses against the rocker arm to provide a maximum amount of valve lift relative to operating conditions in which other portions of the cam are engaged with the rollers. In other words, during operating conditions in which the nose is engaged with the rollers of the rocker arm, the rocker arm's corresponding coupled valve can move to a fully open position (e.g., a position such as one in which intake air flows into the cylinder through the valve).

[0076] Each cam further includes a base segment 428. Base segment 428 is the outer segment of each cam located closest to the rotational axis 432. Base segment 428 is located along the periphery of base circle segment 418 and corresponds to a portion of each cam that provides the minimum amount of valve lift during an operating condition in which base segment 428 engages a roller of a rocker arm. In other words, during an operating condition in which base segment 428 engages a roller of a rocker arm, the corresponding coupled valve of the rocker arm can move to (or remain in) a fully closed position.

[0077] Each cam includes a base segment 428 that engages a ramp segment 430 at a first axis 424 and a second axis 426, wherein the first axis 424 and the second axis 426 extend radially away from the rotation axis 432. The ramp segment 430 and the nose 420 together form a lobe (e.g., a cam lobe) of each cam (e.g., the first cam 401, the second cam 403, and the third cam 405). Figure 4 In the example shown, the first axis 424 is angled at a first angle 433 relative to the length 416, and the second axis 426 is angled at a second angle 435 relative to the length 416, wherein the first angle 433 and the second angle 435 are the same angular amount in opposite directions about the rotation axis 432. In other examples, the first angle 433 and the second angle 435 can be angles of different amounts relative to each other, and / or the first angle 433 and the second angle 435 can be angles of different amounts relative to each other. Figure 4 The quantities shown are angles of different magnitudes.

[0078] The ramp segment 430 of each cam is a portion that is located farther from the rotation axis 432 than the length 425 between the base segment 428 and the rotation axis 432 (e.g., the radius of the base segment 428) and closer to the rotation axis 432 than the length between the nose of the cam and the rotation axis 432 (e.g., the length 416 between the nose 420 of the third cam 405 and the rotation axis 432). Figure 2 During operating conditions in which the rollers of a rocker arm of the intake valve assembly 260 (shown in FIG. 1 and described above) are engaged, the ramp segment 430 presses against the rocker arm to provide an amount of valve lift that is greater than the base segment 428 and less than the nose. In other words, during operating conditions in which the ramp segment 430 is engaged with the rollers of the rocker arm, the corresponding coupled valve of the rocker arm can be driven (e.g., can be moved) to a plurality of positions between the fully closed position and the fully open position (as described above).

[0079] As shown in the enlarged view of inset 406, an outer surface 440 of the first cam 401 forms a ramp segment of the first cam 401, an outer surface 442 of the second cam 403 forms a ramp segment of the second cam 403, and an outer surface 444 of the third cam 405 forms a ramp segment of the third cam 405. The outer surface 440 of the first cam 401 tapers toward the nose 423 and base segment 428 of the first cam 401 at a first curvature, the outer surface 442 of the second cam 403 tapers toward the nose 421 and base segment 428 of the second cam 403 at a second curvature, and the outer surface 444 of the third cam 405 tapers toward the nose 420 and base segment 428 of the third cam 405 at a third curvature, wherein the first curvature, the second curvature, and the third curvature are each different relative to one another. For example, the outer surface 440 of the first cam 401 is positioned a shorter distance from the rotation axis 432 than the distance between the outer surface 442 of the second cam 403 and the rotation axis 432. Additionally, the outer surface 440 of the first cam 401 is positioned a shorter distance from the rotation axis 432 than the distance between the outer surface 444 of the third cam 405 and the rotation axis 432. In other words, the thickness of the second cam 403 along the entire circumference of the ramp segment of the second cam 403 (e.g., at the outer surface 442 of the second cam 403) is greater than the thickness of the first cam 401 along the entire circumference of the ramp segment of the first cam 401 (e.g., at the outer surface 440 of the first cam 401), and the thickness of the third cam 405 along the entire circumference of the ramp segment of the third cam 405 (e.g., at the outer surface 444 of the third cam 405) is greater than the thickness of the second cam 403 along the entire circumference of the ramp segment of the second cam 403.

[0080] For example, as indicated by an example axis 408 disposed perpendicular to the outer surface 440 of the first cam 401 at a location along the perimeter of the ramp segment of the first cam 401, a corresponding outer surface 442 of the second cam 403 aligned with the axis 408 is positioned a distance 410 from the outer surface 440 of the first cam 401, and a corresponding outer surface 444 of the third cam 405 aligned with the axis 408 is positioned a distance 412 from the outer surface 440 of the first cam 401, where the distance 412 is greater than the distance 410. In some examples, the curvature (e.g., angle of curvature) of the outer surface 442 of the second cam 403 and the curvature of the outer surface 444 of the third cam 405 can be similar to the curvature of the outer surface 440 of the first cam 401. Figure 4In the view shown, the outer surface 442 of the second cam 403 is offset from the outer surface 440 of the first cam 401 by a first amount, and the outer surface 444 of the third cam 405 is offset from the outer surface 440 of the first cam 401 by a second amount, wherein the first amount and the second amount each vary along the curvature of the outer surface 440 of the first cam 401, and wherein the second amount is greater than the first amount at each position along the outer surface 440 of the first cam 401 (e.g., such that for each position along the outer surface 440 of the first cam 401, an axis positioned perpendicular to the position is aligned with both the corresponding position at the outer surface 442 of the second cam 403 and the corresponding position at the outer surface 444 of the third cam 405, wherein the corresponding position at the outer surface 444 is farther away from the position on the outer surface 440 along the axis than the corresponding position at the outer surface 442).

[0081] By configuring the cams to have different shapes (e.g., cam lobe profiles) as described above, the first cam 401, the second cam 403, and the third cam 405 each engage with a valve assembly (e.g., an intake valve assembly and / or an exhaust valve assembly) of an engine cylinder in a different manner. For example, because the length 416 from the rotational axis 432 to the nose 420 of the third cam 405 is greater than the length from the rotational axis 432 to the nose 421 of the second cam 403, and because the third cam 405 is configured to drive a deactivatable valve assembly and the second cam 403 is configured to drive a non-deactivatable valve assembly of the same engine, the valves driven by the second cam 403 and the third cam 405 have the same amount of lift (e.g., the amount of opening of the valve in a fully open position relative to a fully closed position, where the fully open position corresponds to the maximum pivoting amount of the rocker arm coupled to the valve due to engagement of the nose with the rocker arm). The amount of lift may also be referred to herein as lift height.

[0082] Similarly, because the third cam 405 is adapted to actuate a deactivatable valve of the engine (such as Figure 2 The second cam 403 is adapted to actuate a non-deactivatable valve of the same engine (e.g., a valve of the intake valve assembly 260 of the second engine 203), so that the curvature of the third cam 405 (e.g., the outer surface 444 of the third cam 405) is different from the curvature of the second cam 403 (e.g., the outer surface 442 of the second cam 403), so that the valve lift rate, valve closing rate, and valve overlap of each deactivatable valve and non-deactivatable valve of the engine are the same for each cylinder. For example, as described above with reference to Figure 2As described above, the deactivatable valve assembly coupled to the third cam 405 may include different components than the non-deactivatable valve assembly coupled to the second cam 403 (e.g., a deactivatable rocker arm and a deactivatable hydraulic lash adjuster having different internal oil passages, pins, springs, bearings, etc.). Consequently, the deactivatable valve assembly may have different inherent operating characteristics than the non-deactivatable valve assembly (e.g., a different amount of rocker arm pivot resistance, a different amount of lubrication, etc.). The different curvatures of the second cam 403 and the third cam 405 enable the valves of the deactivatable valve assembly to be driven by the third cam 405 at the same valve opening and closing rates as the valves of the non-deactivatable valve assembly driven by the second cam 403. In other words, the second cam 403 drives the valves of the non-deactivatable valve assembly, and the third cam 405 drives the valves of the deactivatable valve assembly, so that the difference in the inherent operating characteristics of the valve assemblies is compensated by the shapes of the second cam 403 and the third cam 405, resulting in the valves having the same opening and closing rates.

[0083] Additionally, configuring the second cam 403 and the third cam 405 in this manner enables each non-deactivatable cylinder to include a valve actuated by the same cam as the second cam 403, and each deactivatable cylinder to include a valve actuated by the same cam as the third cam 405, to have the same intake and exhaust valve overlap, as described below with reference to FIG. Figures 5 and 6 As described in the example of FIG. , configuring the valves of the non-deactivatable cylinders to have the same valve lift timing, valve overlap, and valve lift amount as the deactivatable cylinders via the second cam 403 and the third cam 405 can increase combustion stability of the engine by reducing torque imbalance between each cylinder and reducing variation (e.g., difference) in the amount of air and exhaust gas (e.g., combusted fuel / air) residing in each cylinder of the engine after each combustion cycle. For example, each cylinder can have the same amount of air and / or exhaust gas residuals relative to every other cylinder of the engine during each combustion cycle.

[0084] While the first cam 401, the second cam 403, and the third cam 405 described above are intake cams, the exhaust cams may include a similar relative configuration (e.g., a shape difference between each exhaust cam relative to each other exhaust cam similar to the shape difference between the first cam 401, the second cam 403, and the third cam 405). In one example, an engine that includes only non-deactivatable cylinders may include an intake cam having only a first intake cam profile and an exhaust cam having only a first exhaust cam lobe profile (which may be referred to herein as a fourth cam lobe profile). In another example, an engine that includes both deactivatable and non-deactivatable cylinders (as described above) may include a deactivatable intake valve assembly actuated by a cam similar to the third cam 405 coupled to the deactivatable cylinders of the engine as described above. The deactivatable cylinders may also be coupled to a deactivatable exhaust valve assembly actuated by an exhaust cam having a first exhaust cam lobe profile (which may be referred to herein as a fifth cam lobe profile). A non-deactivatable cylinder of the same engine coupled to a non-deactivatable intake valve assembly driven by a cam similar to the second cam 403 described above may additionally be coupled to a non-deactivatable exhaust valve assembly driven by an exhaust cam having a third exhaust cam lobe profile (which may be referred to herein as a sixth cam lobe profile). The fourth cam lobe profile, the fifth cam lobe profile, and the sixth cam lobe profile are completely different from one another. The exhaust cam having the fifth cam lobe profile is shaped differently (e.g., having different ramp segments, lengths from the axis of rotation to the nose, etc.) relative to the exhaust cam having the sixth cam lobe profile, and the difference in shape may result in the exhaust valves driven by each exhaust cam having the same valve lift timing and valve lift amount (e.g., similar to the examples described above with reference to the intake valves, the second cam 403, and the third cam 405).

[0085] Figure 5 Show instructions in a similar way to the above reference Figure 2 A graph 500 of deactivatable intake valve and deactivatable exhaust valve lift amounts during a single combustion cycle of a deactivatable cylinder of the second engine 203 is depicted. The graph 500 is further illustrated in a manner similar to that described above with reference to FIG. Figure 2 The lift amount of the non-deactivatable intake valve and the non-deactivatable exhaust valve during a single combustion cycle of the non-deactivatable cylinder of the engine of the first engine 201. Figure 5 In the example shown, the deactivatable intake valve may be included in a similar Figure 2 The exhaust valve may be included in a valve assembly similar to the valve assembly 262 shown and described above. Figure 2 In the valve assembly of the valve assembly 263 shown and described above, where the valve assembly 262 is composed of a valve having a third intake cam lobe profile (e.g., Figure 4The non-deactivatable intake valves may be included in a configuration similar to the Figure 2 The non-deactivatable exhaust valves may be included within a valve assembly of the valve assembly 260 of the first engine 201 shown, and the non-deactivatable exhaust valves may be included in a valve assembly similar to the valve assembly 261 of the first engine 201, wherein the valve assembly 260 is driven by an intake cam 220 having a first intake cam lobe profile (e.g., the first intake cam lobe profile 400), and the valve assembly 261 is driven by a cam 221 having a first exhaust cam lobe profile.

[0086] Curve 508 shows the amount of lift (e.g., opening amount) of the exhaust valve of a deactivatable cylinder of an engine similar to second engine 203, and curve 510 shows the amount of lift of the intake valve of the same deactivatable cylinder. Curves 508 and 510 correspond to the amount of valve lift during a single combustion cycle of the deactivatable cylinder.

[0087] Curve 512 illustrates the amount of lift of the exhaust valve of a non-deactivatable cylinder of an engine similar to the first engine 201, and curve 514 illustrates the amount of lift of the intake valve of the same non-deactivatable cylinder. Curves 512 and 514 correspond to the amount of valve lift during a single combustion cycle of the non-deactivatable cylinder, where the single combustion cycle of the non-deactivatable cylinder has the same phase (e.g., relative crankshaft and camshaft angles) as the single combustion cycle of the deactivatable cylinder.

[0088] As shown in graph 500, each of the non-deactivatable valves has the same first amount of valve lift in a fully open position as indicated by axis 511, and each of the deactivatable valves has the same second amount of valve lift in a fully open position as indicated by axis 513, wherein the first amount is different from the second amount. Figure 4 As described above, the length (e.g., length 416) from the rotational axis to the nose of the cam that actuates the deactivatable intake valve (e.g., from rotational axis 432 to nose 420) can be different from the length from the rotational axis to the nose of the cam that actuates the non-deactivatable intake valve (e.g., nose 423 of first cam 401). Similarly, the nose of the cam that actuates the non-deactivatable exhaust valve can be positioned at a different distance from the rotational axis of the cam relative to the distance between the rotational axis and the nose of the cam that actuates the deactivatable exhaust valve. Consequently, the deactivatable intake valve and the non-deactivatable intake valve are actuated with different amounts of valve lift (e.g., valve opening) in the fully open position, and the deactivatable exhaust valve and the non-deactivatable exhaust valve are actuated with different amounts of valve lift in the fully open position.

[0089] In addition, as shown in the first illustration 502, the opening rate of the deactivatable exhaust valve of the engine similar to the second engine 203 is different from the opening rate of the non-deactivatable exhaust valve of the engine similar to the second engine 201. For example, at the crank angle θ1 shown in the first illustration 502, the deactivatable exhaust valve of the second engine begins to open (e.g., begins to move away from the fully closed position toward the fully open position). However, the non-deactivatable exhaust valve of the first engine does not begin to open until crank angle θ2, where crank angle θ2 is greater than crank angle θ1 (as shown by angle 517). At crank angle θ2, the valve lift of the deactivatable exhaust valve has increased by an amount 516 that is greater than the valve lift of the non-deactivatable exhaust valve. Therefore, the deactivatable exhaust valve and the non-deactivatable exhaust valve each continue to move toward the fully open position at different valve opening rates after crank angle θ2.

[0090] Second inset 504 illustrates valve overlap of a deactivatable exhaust valve with a deactivatable intake valve of the same cylinder of the same engine (e.g., the same cylinder and engine including the deactivatable exhaust valve), with curve 510 illustrating valve lift of the intake valve. Additionally, second inset 504 illustrates valve overlap of a non-deactivatable exhaust valve with a non-deactivatable intake valve of the same cylinder of the same engine (e.g., the same cylinder and engine including the non-deactivatable exhaust valve), with curve 514 illustrating valve lift of the intake valve.

[0091] At crank angle θ4, shown in the second inset 504, the deactivatable intake valve of the second engine begins to open (e.g., begins to move away from a fully closed position toward a fully open position). However, the non-deactivatable intake valve of the first engine does not begin to open until crank angle θ5, where crank angle θ5 is a crank angle amount greater than crank angle θ4 (as shown by angle 519). At crank angle θ5, the valve lift of the deactivatable intake valve has increased by an amount 521 greater than the valve lift of the non-deactivatable intake valve. Therefore, the deactivatable and non-deactivatable intake valves each continue to move toward the fully open position at different valve opening rates after crank angle θ5. For example, due to the different valve opening rates, the valve lift of the deactivatable intake valve at crank angle θ6 is greater than the valve lift of the non-deactivatable intake valve by an amount 525, where amount 525 is greater than amount 521.

[0092] Additionally, at crank angle θ5, second inset 504 illustrates the deactivatable exhaust valve and the non-deactivatable exhaust valve moving from a partially open position (e.g., a partially closed position relative to a fully open position at crank angle θ3, where crank angle θ3 is the crank angle at which both curve 512 and curve 508 intersect axis 511) toward a fully closed position at different valve closing rates. At crank angle θ5, the valve lift of the deactivatable exhaust valve is greater than the valve lift of the non-deactivatable exhaust valve by an amount 520. Due to the different valve closing rates, the non-deactivatable exhaust valve moves to a fully closed position at crank angle θ6, while the deactivatable exhaust valve moves to a fully closed position at crank angle θ7, where crank angle θ7 is greater than crank angle θ6 (as indicated by angle 527). Consequently, at crank angle θ6, the valve lift of the deactivatable exhaust valve is greater than the valve lift of the non-deactivatable exhaust valve by an amount 523.

[0093] As shown in third inset 506, the deactivatable intake valve and the non-deactivatable intake valve move from a partially open position (e.g., a partially closed position relative to a fully open position at crank angle θ8, where crank angle θ8 is the crank angle at which both curve 510 and curve 514 intersect axis 511) toward a fully closed position at different valve closing rates. At crank angle θ9, the valve lift of the deactivatable intake valve is greater than the valve lift of the non-deactivatable intake valve by an amount 522. Due to the different valve closing rates, the non-deactivatable intake valve moves to the fully closed position at crank angle θ9, while the deactivatable intake valve moves to the fully closed position at crank angle θ10, where crank angle θ10 is greater than crank angle θ9 (as shown by angle 529).

[0094] Figure 6 Show instructions as above reference Figure 5 600 of the intake and exhaust valve lift amounts for the deactivatable cylinders described with reference to graph 500 and depicted in the same engine including deactivatable cylinders (e.g., similar to the engine described above with reference to FIG. Figure 2 The amount of intake and exhaust valve lift during a single combustion cycle of a non-deactivatable cylinder of the second engine 203 described.

[0095] Graph 600 shows (respectively) the diagrams described above with reference to Figure 5 Graph 600 further illustrates curve 608 illustrating the valve lift amount of a non-deactivatable exhaust valve, and curve 610 illustrating the valve lift amount of a non-deactivatable intake valve (e.g., a valve having a valve lift corresponding to curves 508 and 510 as described above) of the same engine including the above-described deactivatable exhaust valve and deactivatable intake valve.

[0096] The first illustration 602 shows a diagram similar to the one in the reference above. Figure 5Specifically, the first inset 602 shows the opening rate of the deactivatable exhaust valve (as shown by curve 508) relative to the opening rate of the non-deactivatable exhaust valve (as shown by curve 608). Figure 5 In the example of the first illustration 502 shown, since the non-deactivatable exhaust valve is provided by a cam having a first exhaust cam lobe profile (e.g., similar to Figure 2 The exhaust cam 221 of the first engine 201 shown is driven and the deactivatable exhaust valve is driven by a cam having a third exhaust cam lobe profile (e.g., similar to the cam 241 of the second engine 203 and Figure 3 The deactivatable exhaust valve and the non-deactivatable exhaust valve have different valve opening rates (as shown by the valve lift amount 516 between curve 508 and curve 512). Figure 6 In the example shown in the first illustration 602 of FIG, since the deactivatable exhaust valve is actuated by a cam having a third exhaust cam lobe profile and the non-deactivatable exhaust valve is actuated by a cam having a second exhaust cam lobe profile different from the first exhaust cam lobe profile (e.g., similar to Figure 2 The cam 231 of the second engine 203 is shown as well as Figure 3 The deactivatable exhaust valve and the non-deactivatable exhaust valve have the same valve opening rate (such as there is no similar difference between the curve 508 and the curve 608). Figure 5 The difference in amount 512 is shown).

[0097] By configuring the deactivatable exhaust valves and non-deactivatable exhaust valves of the same engine to have the same valve opening rate (e.g., valve lift rate) via a cam including the second exhaust cam lobe profile and the third exhaust cam lobe profile as described above, combustion stability of the engine can be increased. In one example, configuring the exhaust valves of the deactivatable cylinders and the non-deactivatable cylinders to have the same valve opening rate can reduce the difference in the amount of combustion gas (e.g., combusted air / fuel) remaining in each engine cylinder relative to each other cylinder after each complete combustion cycle.

[0098] The second illustration 604 shows a diagram similar to the one in the reference above. Figure 5 Specifically, second illustration 604 illustrates valve overlap of a deactivatable exhaust valve (as indicated by curve 508) with a deactivatable intake valve (as indicated by curve 510) of the same cylinder, and additionally illustrates valve overlap of a non-deactivatable exhaust valve (indicated by curve 608) of the same engine with a non-deactivatable intake valve of the same cylinder (e.g., the same non-deactivatable cylinder coupled to the non-deactivatable exhaust valve). Figure 5In the example of the second illustration 504 shown, since the non-deactivatable exhaust valve is provided by a cam having a first exhaust cam lobe profile (e.g., similar to Figure 2 The deactivatable exhaust valves are driven by cams having a third exhaust cam profile (e.g., similar to cams 241 and 242 of the second engine 203). Figure 3 The deactivatable exhaust valve and the non-deactivatable exhaust valve have different valve closing rates (as shown by the valve lift amount 520 between curve 508 and curve 512). Figure 6 In the example shown in the second illustration 604 of FIG, since the deactivatable exhaust valve is actuated by a cam having a third exhaust cam lobe profile, and the non-deactivatable exhaust valve is actuated by a cam having a second exhaust cam lobe profile (e.g., similar to Figure 2 The cam 231 of the second engine 203 is shown as well as Figure 3 The deactivatable exhaust valve and the non-deactivatable exhaust valve have the same valve closing rate (e.g., there is no similar difference between the curve 508 and the curve 608). Figure 5 The difference in amount 520 is shown).

[0099] The second inset 604 further illustrates the opening rate of the deactivatable intake valve of the engine (as shown by curve 510) relative to the opening rate of the non-deactivatable intake valve of the same engine (as shown by curve 610). Figure 5 In the example of the second illustration 504 shown, since the non-deactivatable intake valve is provided by a cam having a first intake cam lobe profile (e.g., similar to Figure 2 The cam 220 of the first engine 201 is shown as well as Figure 4 The deactivatable intake valve is driven by a cam having a third intake cam lobe profile (e.g., similar to the cam 240 of the second engine 203, Figure 3 Cams 306 and 308 are shown and Figure 4 The deactivatable intake valve and the non-deactivatable intake valve have different valve opening rates (as shown by the valve lift amount 525 between the curve 510 and the curve 514). Figure 6 In the example shown in the second illustration 604 of FIG, since the deactivatable intake valve is actuated by a cam having a third intake cam lobe profile and the non-deactivatable intake valve is actuated by a cam having a second intake cam lobe profile (e.g., similar to Figure 2 The cam 230 of the second engine 203 is shown. Figure 3 Cams 304 and 310 are shown and Figure 4The deactivatable intake valve and the non-deactivatable intake valve have the same valve opening rate (such as there is no similar difference between the curve 510 and the curve 610). Figure 5 The difference in amount 525 is shown).

[0100] By configuring the deactivatable exhaust valves and the deactivatable intake valves to have the same amount of valve overlap relative to the valve overlap of the non-deactivatable exhaust valves and non-deactivatable intake valves of the same engine, combustion stability can be increased. As described above, because each of the exhaust valves has the same valve closing rate and each of the intake valves has the same valve opening rate, each of the cylinders (e.g., the deactivatable cylinders and the non-deactivatable cylinders) has the same amount of valve overlap. In one example, configuring the cylinders to each have the same amount of valve overlap can increase combustion stability and / or reduce torque imbalance in one or more cylinders. For example, as described above, the difference in the amount of combustion gases (e.g., burned air / fuel) remaining in each engine cylinder relative to each other cylinder after each complete combustion cycle can be reduced.

[0101] The third illustration 606 shows a diagram similar to the one in the reference above. Figure 5 Specifically, the third inset 606 shows the valve closing rate of the deactivatable intake valve (as shown by curve 510) relative to the valve closing rate of the non-deactivatable intake valve of the same cylinder (as shown by curve 610). As described above, Figure 5 In the example of the third illustration 506 shown, since the non-deactivatable intake valve is provided by a cam having a first intake cam lobe profile (e.g., similar to Figure 2 The cam 220 of the first engine 201 is shown as well as Figure 4 The deactivatable intake valve is driven by a cam having a third intake cam lobe profile (e.g., similar to the cam 240 of the second engine 203, Figure 3 Cams 306 and 308 are shown and Figure 4 The deactivatable intake valve and the non-deactivatable intake valve have different valve closing rates (as shown by the valve lift amount 522 between the curve 510 and the curve 514). Figure 6 In the example shown in the third illustration 606 of FIG, since the deactivatable intake valve is actuated by a cam having a third intake cam lobe profile, and the non-deactivatable intake valve is actuated by a cam having a second intake cam lobe profile (e.g., similar to FIG. Figure 2 The cam 230 of the second engine 203 is shown. Figure 3 Cams 304 and 310 are shown and Figure 4The deactivatable intake valve and the non-deactivatable intake valve have the same valve closing rate (such as there is no similar difference between the curve 510 and the curve 610). Figure 5 The difference in amount 522 is shown).

[0102] By configuring the deactivatable intake valves and non-deactivatable intake valves of the same engine to have the same valve closing rate via cams having different cam lobe profiles as described above, combustion stability can be increased. In one example, configuring the deactivatable intake valves and non-deactivatable intake valves of the same engine to have the same valve closing rate can increase combustion stability and / or reduce the difference in the amount of combustion gases (e.g., burned air / fuel) remaining in each engine cylinder relative to each other cylinder after each complete combustion cycle. Additionally, in the above reference to Figure 6 In the depicted configuration, deactivatable intake valves and non-deactivatable intake valves of the same engine may have the same amount of valve lift (as indicated by axis 513 ), and deactivatable exhaust valves and non-deactivatable exhaust valves of the same engine may have the same amount of valve lift.

[0103] Figures 3 and 4 An example configuration with relative positioning of various components is shown. If shown as being in direct contact with each other or directly coupled, such elements may be referred to as being in direct contact or directly coupled, respectively, at least in one example. Similarly, elements shown as being adjacent or adjacent to each other may be adjacent or adjacent to each other, respectively, at least in one example. As an example, components arranged to be in coplanar contact with each other may be referred to as being in coplanar contact. As another example, in at least one example, elements are positioned to be spaced apart from each other, with only space between them and no other components, which may be referred to as such. As another example, elements shown as being above / below each other, on opposite sides of each other, or on the left or right side of each other may be referred to as such. In addition, as shown in the accompanying drawings, in at least one example, the topmost element or point of an element may be referred to as the "top" of a component, and the bottommost element or point of an element may be referred to as the "bottom" of a component. As used herein, top / bottom, up / down, above / below may be relative to the vertical axis of the accompanying drawings and are used to describe the positioning of the elements of the accompanying drawings relative to each other. Thus, in one example, an element shown as being above other elements is positioned vertically above the other elements. As yet another example, shapes of elements depicted in the accompanying drawings may be referred to as having those shapes (e.g., such as being round, straight, flat, curved, rounded, chamfered, angled, etc.). Furthermore, in at least one example, elements shown as crossing each other may be referred to as crossing elements or crossing each other. Furthermore, in one example, an element shown as being inside another element or an element shown as being outside another element may be referred to as such.

[0104] In this way, the engine is configured to have deactivatable intake valves and deactivatable exhaust valves driven by a cam including a third cam lobe profile to offset the different operating characteristics of the deactivatable valve assembly relative to the non-deactivatable valve assembly. The engine is also configured to have non-deactivatable intake valves and non-deactivatable exhaust valves driven by a cam including a second cam lobe profile so that the intake valves and exhaust valves of each cylinder have the same valve opening rate, valve closing rate, and valve overlap relative to every other cylinder of the same engine. The technical effect of configuring the deactivatable valves to be driven by a cam having a third cam lobe profile and configuring the non-deactivatable valves to be driven by a cam having a second cam lobe profile is to increase combustion stability and reduce the difference in the amount of combustion gases (e.g., burned air / fuel) remaining in each engine cylinder after each complete combustion cycle relative to the amount of combustion gases in every other cylinder of the same engine.

[0105] In one embodiment, a system includes: a camshaft including a first plurality of cams and a second plurality of cams, each cam of the first plurality of cams having a first cam lobe profile and each cam of the second plurality of cams having a different second cam lobe profile; a plurality of deactivatable cylinder valves actuated by the first plurality of cams; and a plurality of non-deactivatable cylinder valves actuated by the second plurality of cams. In a first example of the system, each valve of the plurality of deactivatable cylinder valves is drivable from a fully closed position to a fully open position by a corresponding cam of the first plurality of cams, each valve of the plurality of non-deactivatable cylinder valves is drivable from a fully closed position to a fully open position by a corresponding cam of the second plurality of cams, and an amount of lift of each valve of the plurality of deactivatable cylinder valves from the fully closed position to the fully open position is the same amount as an amount of lift of each valve of the plurality of non-deactivatable cylinder valves from the fully closed position to the fully open position. A second example of the system optionally includes the first example, and further includes wherein the first cam lobe profile includes a first base segment, a first nose, and a first bevel segment, the second cam lobe profile includes a second base segment, a second nose, and a second bevel segment, and wherein the radius of the first base segment and the radius of the second base segment are the same length. A third example of the system optionally includes one or both of the first and second examples, and further includes wherein the length from the center of the first base segment to the first nose in a radial direction of the first base segment and the length from the center of the second base segment to the second nose in a radial direction of the second base segment are different lengths. A fourth example of the system optionally includes one or more or each of the first to third examples, and further includes wherein the first bevel segment tapers toward the first nose and the first base segment at a first curvature, wherein the second bevel segment tapers toward the second nose and the second base segment at a second curvature, and wherein the first curvature is different from the second curvature. A fifth example of the system optionally includes one or more or each of the first to fourth examples, and further includes wherein each position along the entire circumference of the first ramp segment is offset by a greater amount in a direction away from the rotational axis of the camshaft than each corresponding position along the entire circumference of the second ramp segment. A sixth example of the system optionally includes one or more or each of the first to fifth examples, and further includes wherein each cam of the first plurality of cams includes a first nose positioned a first length from the rotational axis of the camshaft in a radial direction of the rotational axis, and each cam of the second plurality of cams includes a second nose positioned a second, different length from the rotational axis of the camshaft in a radial direction.The seventh example of the system optionally includes one or more or each of the first to sixth examples, and also includes wherein the plurality of deactivatable cylinder valves driven by a first plurality of cams are adapted to have a first valve lift when driven by the cam lobe of each cam of the first plurality of cams, wherein the plurality of non-deactivatable cylinder valves driven by a second plurality of cams are adapted to have a second valve lift when driven by the cam lobe of each cam of the second plurality of cams, and wherein the first valve lift is equal to the second valve lift.

[0106] In another embodiment, a system includes an intake camshaft and an exhaust camshaft; a first intake cam and a second intake cam coupled to the intake camshaft, the first intake cam having a different cam lobe profile than the second intake cam, the first intake cam being adapted to actuate an intake valve of a first engine cylinder and the second intake cam being adapted to actuate an intake valve of a second engine cylinder; and a first exhaust cam and a second exhaust cam coupled to the exhaust camshaft, the first exhaust cam having a different cam lobe profile than the second exhaust cam, the first exhaust cam being adapted to actuate an exhaust valve of the first engine cylinder and the second exhaust cam being adapted to actuate an exhaust valve of the second engine cylinder. In the first example of the system, the cam lobe profile of the first intake cam is different from the cam lobe profile of the first exhaust cam, and the cam lobe profile of the second intake cam is different from the cam lobe profile of the second exhaust cam. The second example of the system optionally includes the first example and further includes the following: valve overlap of the intake and exhaust valves of the first cylinder within a single combustion cycle of the first cylinder is the same amount as valve overlap of the intake and exhaust valves of the second cylinder within a single combustion cycle of the second cylinder. A third example of the system optionally includes one or both of the first and second examples, and further includes wherein a valve opening rate of the intake valve of the first cylinder within a single combustion cycle of the first cylinder is the same as a valve opening rate of the intake valve of the second cylinder within a single combustion cycle of the second cylinder. A fourth example of the system optionally includes one or more or each of the first through third examples, and further includes wherein a valve closing rate of the exhaust valve of the first cylinder within a single combustion cycle of the first cylinder is the same as a valve closing rate of the exhaust valve of the second cylinder within a single combustion cycle of the second cylinder. A fifth example of the system optionally includes one or more or each of the first through fourth examples, and further includes wherein the intake valve and the exhaust valve of the first engine cylinder are non-deactivatable valves each actuated by a corresponding non-deactivatable rocker arm, and wherein the intake valve and the exhaust valve of the second engine cylinder are deactivatable valves each actuated by a corresponding deactivatable rocker arm.A sixth example of the system optionally includes one or more or each of the first to fifth examples, and also includes wherein the first engine cylinder and the second engine cylinder are arranged in a first cylinder bank, and also includes an opposed second cylinder bank, the second cylinder bank including: a second intake camshaft and a second exhaust camshaft; a third intake cam and a fourth intake cam coupled to the second intake camshaft, the third intake cam having the same cam lobe profile as the first intake cam, and the fourth intake cam having the same cam lobe profile as the second intake cam, the third intake cam being suitable for driving an intake valve of a third engine cylinder arranged in the second cylinder bank, and the fourth intake cam being suitable for driving an intake valve of a fourth engine cylinder arranged in the second cylinder bank; and a third exhaust cam and a fourth exhaust cam coupled to the second exhaust camshaft, the third exhaust cam having the same cam lobe profile as the first exhaust cam, and the fourth exhaust cam having the same cam lobe profile as the second exhaust cam, the third exhaust cam being suitable for driving an exhaust valve of the third engine cylinder, and the fourth exhaust cam being suitable for driving an exhaust valve of the fourth engine cylinder.

[0107] In one embodiment, a series of engines includes: a first engine including a first plurality of cylinders having only a first set of non-deactivatable intake valves and a first camshaft including a first plurality of cams adapted to actuate the first set of non-deactivatable intake valves, wherein all cams of the first plurality of cams have the same first cam lobe profile; and a second engine including a second plurality of cylinders having a second set of non-deactivatable intake valves, a third plurality of cylinders having a third set of deactivatable intake valves, and a second camshaft including a second plurality of cams adapted to actuate the second set of non-deactivatable intake valves and a third plurality of cams adapted to actuate the third set of deactivatable intake valves, wherein the second plurality of cams have a second cam lobe profile and the third plurality of cams have a third cam lobe profile, wherein the first cam lobe profile, the second cam lobe profile, and the third cam lobe profile are all different from one another. In the first example of the series, each cam of the first plurality of cams, the second plurality of cams, and the third plurality of cams has a different length from a nose of each cam to a base segment of each cam along an axis perpendicular to the nose. The second example of the series optionally includes the first example, and further includes wherein: the first plurality of cylinders further includes only a first group of non-deactivatable exhaust valves, and the first engine further includes a third camshaft, the third camshaft including a fourth plurality of cams suitable for driving the first group of non-deactivatable exhaust valves, wherein all cams of the fourth plurality of cams have the same fourth cam lobe profile; and the second group of non-deactivatable exhaust valves is coupled to the second plurality of cylinders, the third group of deactivatable exhaust valves is coupled to the third plurality of cylinders, and the second engine includes a fourth camshaft, the fourth camshaft including a fifth plurality of cams suitable for driving the second group of non-deactivatable exhaust valves and a sixth plurality of cams suitable for driving the third group of deactivatable exhaust valves, wherein the fifth plurality of cams has a fifth cam lobe profile, and the sixth plurality of cams has a sixth cam lobe profile, wherein the fourth cam lobe profile, the fifth cam lobe profile and the sixth cam lobe profile are all different from each other. The third example of the series optionally includes one or both of the first and second examples, and also includes wherein each cylinder of the first plurality of cylinders is coupled to a corresponding intake valve of a first group of non-deactivatable intake valves and a corresponding exhaust valve of a first group of non-deactivatable exhaust valves, the intake valves and the exhaust valves having a first amount of valve overlap in each combustion cycle of their corresponding coupled cylinders; wherein each cylinder of the second plurality of cylinders is coupled to a corresponding intake valve of a second group of non-deactivatable intake valves and a corresponding exhaust valve of a second group of non-deactivatable exhaust valves, the intake valves and the exhaust valves of the second group having a second amount of valve overlap in each combustion cycle of their corresponding coupled cylinders; wherein each cylinder of the third plurality of cylinders is coupled to a corresponding intake valve of a third group of deactivatable intake valves and a corresponding exhaust valve of a third group of deactivatable exhaust valves, the intake valves and the exhaust valves of the third group having a third amount of valve overlap in each combustion cycle of their corresponding coupled cylinders; and wherein the second amount and the third amount are the same amount of overlap that is different from the first amount.The fourth example of the series optionally includes one or more or each of the first to third examples, and also includes wherein each valve of the second group of non-deactivatable intake valves and the third group of deactivatable intake valves has the same first opening rate and the same first closing rate, and wherein each valve of the first group of non-deactivatable intake valves has a different second opening rate and a different second closing rate.

[0108] In another representation, an engine includes: an intake camshaft and an exhaust camshaft; a first intake cam and a second intake cam coupled to the intake camshaft, the first intake cam and the second intake cam having different outer surface curvatures (e.g., profiles), the first intake cam being adapted to drive a non-deactivatable intake valve of a first engine cylinder and the second intake cam being adapted to drive a deactivatable intake valve of a second engine cylinder; a first exhaust cam and a second exhaust cam coupled to the exhaust camshaft, the first exhaust cam and the second exhaust cam having different outer surface curvatures (e.g., profiles), the first exhaust cam being adapted to drive a non-deactivatable exhaust valve of the first engine cylinder and the second exhaust cam being adapted to drive a deactivatable exhaust valve of the second engine cylinder; a transmission; and an electric motor selectively coupled to the transmission via one or more clutches, the electric motor being adapted to drive the transmission.

[0109] It should be noted that the example control and estimation routines included herein can be used with various engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in a non-transitory memory and can be performed by a control system including a controller in conjunction with various sensors, actuators and other engine hardware. The specific routines described herein may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc. Thus, the various actions, operations and / or functions shown can be performed in the order shown, in parallel, or omitted in some cases. Similarly, the order of processing is not required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. Depending on the specific strategy used, one or more of the described actions, operations and / or functions may be repeated. In addition, the described actions, operations and / or functions can be graphically represented as code to be programmed into the non-transitory memory of a computer-readable storage medium in the engine control system, wherein the described actions are performed by executing instructions in conjunction with an electronic controller in a system including various engine hardware components.

[0110] It should be understood that the configurations and routines disclosed herein are exemplary in nature, and these specific embodiments are not to be construed in a limiting sense, as many variations are possible. For example, the above technology can be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations disclosed herein, as well as other features, functions, and / or properties.

[0111] The appended claims particularly point out certain combinations and subcombinations regarded as novel and non-obvious, which may refer to "an" element or "a first" element or their equivalent, which should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amendment of the appended claims or by presentation of new claims in this or a related application. Amendments to the appended claims or presentation of new claims, whether broader, narrower, equal, or different in scope to the original claims, are deemed included within the subject matter of the present disclosure.

Claims

1. A system for an engine, comprising: a camshaft comprising a first plurality of cams and a second plurality of cams, each cam in the first plurality of cams having a first cam lobe profile and each cam in the second plurality of cams having a second cam lobe profile different from the first cam lobe profile; a plurality of deactivatable cylinder valves actuated by said first plurality of cams; as well as a plurality of non-deactivatable cylinder valves actuated by said second plurality of cams; wherein the first cam lobe profile comprises a first base segment, a first nose, and a first ramp segment, and the second cam lobe profile comprises a second base segment, a second nose, and a second ramp segment, and wherein a radius of the first base segment and a radius of the second base segment are the same length amount; and wherein a length from a center of the first base segment to the first nose in a radial direction of the first base segment and a length from a center of the second base segment to the second nose in a radial direction of the second base segment are different amounts.

2. The system according to claim 1, wherein each valve of the plurality of deactivatable cylinder valves is capable of being driven from a fully closed position to a fully open position by a corresponding cam of the first plurality of cams, each valve of the plurality of non-deactivatable cylinder valves is capable of being driven from a fully closed position to a fully open position by a corresponding cam of the second plurality of cams, and the lift amount of each valve of the plurality of deactivatable cylinder valves from the fully closed position to the fully open position is the same amount as the lift amount of each valve of the plurality of non-deactivatable cylinder valves from the fully closed position to the fully open position.

3. The system of claim 1 , wherein the first ramp segment tapers toward the first nose and the first base segment at a first curvature, wherein the second ramp segment tapers toward the second nose and the second base segment at a second curvature, and wherein the first curvature is different from the second curvature.

4. The system of claim 1 , wherein each location along the entire circumference of the first ramp segment is offset a greater amount in a direction away from the rotational axis of the camshaft than each corresponding location along the entire circumference of the second ramp segment.

5. The system of claim 1 , wherein each cam of the first plurality of cams includes the first nose positioned a first length away from the rotational axis of the camshaft in a radial direction of the rotational axis of the camshaft, and each cam of the second plurality of cams includes the second nose positioned a second, different length away from the rotational axis of the camshaft in the radial direction.

6. A system according to claim 5, wherein the plurality of deactivatable cylinder valves driven by the first plurality of cams are adapted to have a first valve lift when driven by the cam lobe of each cam of the first plurality of cams, wherein the plurality of non-deactivatable cylinder valves driven by the second plurality of cams are adapted to have a second valve lift when driven by the cam lobe of each cam of the second plurality of cams, and wherein the first valve lift is equal to the second valve lift.

7. A method for an engine, comprising: driving an intake valve of a first engine cylinder via rotation of a first intake cam and driving an intake valve of a second engine cylinder via rotation of a second intake cam, the first intake cam and the second intake cam each being coupled to an intake camshaft, the first intake cam having a different cam lobe profile than the second intake cam; as well as driving an exhaust valve of a first engine cylinder via rotation of a first exhaust cam and driving an exhaust valve of a second engine cylinder via rotation of a second exhaust cam, the first exhaust cam and the second exhaust cam each being coupled to an exhaust camshaft, the first exhaust cam having a different cam lobe profile than the second exhaust cam, The first intake cam and the second intake cam have different lengths along an axis perpendicular to the nose of each cam from the nose to the center of the base segment of each cam.

8. The method of claim 7, wherein the cam lobe profile of the first intake cam is different from the cam lobe profile of the first exhaust cam, and wherein the cam lobe profile of the second intake cam is different from the cam lobe profile of the second exhaust cam.

9. The method of claim 7 further comprising actuating the intake valve and the exhaust valve of the first engine cylinder to have a first amount of valve overlap within a single combustion cycle of the first engine cylinder, and actuating the intake valve and the exhaust valve of the second engine cylinder to have a second amount of valve overlap within a single combustion cycle of the second engine cylinder, the first amount of valve overlap being the same as the second amount of valve overlap.

10. The method of claim 7, wherein the intake valve of the first engine cylinder is driven to have a first valve opening rate within a single combustion cycle of the first engine cylinder, the intake valve of the second engine cylinder is driven to have a second valve opening rate within a single combustion cycle of the second engine cylinder, and the first valve opening rate is the same as the second valve opening rate.

11. The method of claim 7, wherein the exhaust valve of the first engine cylinder is driven to have a first valve closing rate within a single combustion cycle of the first engine cylinder, the exhaust valve of the second engine cylinder is driven to have a second valve closing rate within a single combustion cycle of the second engine cylinder, and the first valve closing rate is the same as the second valve closing rate.

12. The method of claim 7, wherein driving the intake valve of the first engine cylinder via the first intake cam includes engaging the first intake cam with a first non-deactivatable rocker arm, driving the exhaust valve of the first engine cylinder via the first exhaust cam includes engaging the first exhaust cam with a second non-deactivatable rocker arm, driving the intake valve of the second engine cylinder via the second intake cam includes engaging the second intake cam with a first deactivatable rocker arm, and driving the exhaust valve of the second engine cylinder via the second exhaust cam includes engaging the second exhaust cam with a second deactivatable rocker arm.

13. The method of claim 7, wherein the first engine cylinder and the second engine cylinder are disposed in a first cylinder bank, and the method further comprising: driving an intake valve of a third engine cylinder disposed in an opposed second cylinder bank via rotation of a third intake cam, and driving an intake valve of a fourth engine cylinder disposed in the second cylinder bank via rotation of a fourth intake cam, the third and fourth intake cams being each coupled to a second intake camshaft, the third intake cam having a cam lobe profile identical to the first intake cam, and the fourth intake cam having a cam lobe profile identical to the second intake cam; as well as The exhaust valve of the third engine cylinder is driven by the rotation of a third exhaust cam, and the exhaust valve of the fourth engine cylinder is driven by the rotation of a fourth exhaust cam, the third exhaust cam and the fourth exhaust cam are each coupled to a second exhaust camshaft, the third exhaust cam has a cam lobe profile that is the same as that of the first exhaust cam, and the fourth exhaust cam has a cam lobe profile that is the same as that of the second exhaust cam.

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