Method and system for improving the response of a hybrid vehicle

Abstract

Power transmission operating method comprising: Stopping fuel delivery to all engine cylinders and adjusting an actual total number of engine cylinders with operating poppet valves and an actual total number of engine cylinders with deactivated poppet valves in response to a braking torque in the powertrain during vehicle deceleration via a controller; and Adjusting the rotation of the internal combustion engine in response to a vehicle in which the internal combustion engine is not in a sport mode and an electric machine having torque capacity to provide braking torque in the powertrain.

Description

Area

[0001] The present description relates to methods and a system for operating a hybrid powertrain including an internal combustion engine and an electric machine for propelling a vehicle. The methods and systems may be particularly useful for hybrid vehicles that include cylinders that can be deactivated. Background and brief presentation

[0002] A hybrid vehicle may include an internal combustion engine and an electric motor to propel the vehicle. The internal combustion engine may be stopped and not rotating if the driver demand torque can be met via the electric motor. Stopping the internal combustion engine can save fuel and reduce vehicle emissions. However, if a human driver requests a large increase in torque output in the powertrain, the internal combustion engine may need to be restarted to meet the driver demand torque. The driver may notice that maximum torque in the powertrain is only available after the internal combustion engine has started and reaches a powertrain speed. The internal combustion engine may take more than one or two seconds to start and reach a speed at which it can provide torque to the powertrain.As a result, the driver and passengers may notice a delay in the torque delivered to the powertrain. This delay in torque generation can be distracting.

[0003] The inventor herein has recognized the above-mentioned problems and has developed a powertrain operating method comprising: adjusting fuel delivery to all engine cylinders and adjusting an actual total number of cylinders of an engine with operating poppet valves and an actual total number of cylinders of the engine with deactivated poppet valves in response to a desired braking torque in the powertrain during vehicle deceleration via a controller.

[0004] By operating different internal combustion engine cylinders in different valve modes while no fuel is injected into an internal combustion engine during vehicle deceleration, it may be possible to provide braking in the powertrain while enhancing the ability of a powertrain to provide torque in response to a demand for increased internal combustion engine torque after combustion in internal combustion engine cylinders has ceased. For example, if a small amount of braking is demanded in the powertrain and an electric machine has the capacity to provide the desired braking in the powertrain, an internal combustion engine may be rotated with its valves kept closed to reduce internal combustion engine pumping losses.As the engine continues to rotate, engine start-up time can be reduced by eliminating the need to accelerate the engine from zero speed to the transmission speed before torque can be delivered to the transmission from the engine. If a larger amount of braking torque is required in the transmission, the engine cylinders can be operated with valves that open and close, allowing the desired braking in the transmission to be provided by the engine and electric motor, while still preventing fuel from being injected into the engine.

[0005] The present description can provide several advantages. For example, the approach can reduce engine start-up time. Furthermore, the approach can reduce the response time of the powertrain to a request to increase torque in the powertrain. Additionally, the approach can improve the vehicle's fuel efficiency.

[0006] The above advantages as well as other advantages and features of the present description will be readily apparent from the following detailed description when read alone or in conjunction with the accompanying drawings.

[0007] It should be understood that the foregoing summary is provided to introduce, in a simplified form, a selection of concepts further described in the detailed description. It is not intended to identify important or significant features of the claimed subject matter, the scope of which is defined solely in the claims following the detailed description. Furthermore, the claimed subject matter is not limited to implementations that overcome any disadvantages noted above or in any part of this disclosure. Brief description of the drawings

[0008] The advantages described herein will become more fully apparent from reading an example of an embodiment, referred to herein as the detailed description, whether read in isolation or with reference to the drawings, in which: Fig. 1 is a schematic diagram of an internal combustion engine; Fig. 2A, Fig. 2B and Fig. 2C are schematic representations of three example hybrid vehicle powertrains; Fig. 3A and Fig. 3B show exemplary combustion engines with deactivating valves; Fig. 4 shows an exemplary hybrid vehicle operating sequence; and Fig. 5 shows an exemplary method for operating a hybrid vehicle. Detailed description

[0009] This description relates to controlling the powertrain operation of a hybrid vehicle. The hybrid vehicle may include an internal combustion engine as described in Fig. 1. The internal combustion engine may be included in a power transmission or drive train of a hybrid vehicle, as shown in Fig. 2A-2C. The internal combustion engine may also include deactivating cylinders and deactivating poppet valves, as shown in Fig. 3A and Fig. 3B. The hybrid power transmission or drive train can be configured as shown in the operating sequence Fig. 4. The hybrid vehicle can be operated according to the method of Fig. 5 are operated.

[0010] With reference to Fig. 1, an internal combustion engine 10 comprising a plurality of cylinders, of which one cylinder is in Fig. 1, is controlled by an electronic internal combustion engine controller 12. The internal combustion engine 10 consists of the cylinder head 35 and block 33, which enclose the combustion chamber 30 and the cylinder walls 32. The piston 36 is positioned therein and reciprocates via a connection to the crankshaft 40. The flywheel 97 and the ring gear 99 are coupled to the crankshaft 40. The optional starter 96 (e.g., a low-voltage electric machine (operating at less than 30 volts)) includes the pinion shaft 98 and the pinion gear 95. The pinion shaft 98 can selectively advance the pinion gear 95 to engage the ring gear 99. The starter 96 can be mounted directly in the front of the internal combustion engine or in the rear of the internal combustion engine. In some examples, the starter 96 may selectively supply torque to the crankshaft 40 via a belt or chain.In one example, the starter 96 is in a ground state when it is not engaging the engine crankshaft.

[0011] As shown, the combustion chamber 30 communicates with the intake manifold 44 and the exhaust manifold 48 via a corresponding intake poppet valve 52 and exhaust poppet valve 54. Each intake and exhaust valve may be operated by an intake camshaft 51 and an exhaust camshaft 53. The position of the intake camshaft 51 may be determined by the intake camshaft sensor 55. The position of the exhaust camshaft 53 may be determined by the exhaust camshaft sensor 57. The intake valves may be held closed throughout an entire engine cycle while the engine is rotating by deactivating the intake valve actuator 59, which may operate the intake valves electrically, hydraulically, or mechanically. Alternatively, intake valves may be opened and closed during a cycle of the engine. The exhaust valves may be held closed throughout an entire engine cycle (e.g.,The exhaust valves can be kept closed (two engine revolutions) while the engine is rotating by deactivating the exhaust valve actuator 58, which can operate the exhaust valves electrically, hydraulically, or mechanically. Alternatively, exhaust valves can be opened and closed during one engine cycle.

[0012] As shown, fuel injector 66 is positioned to inject fuel directly into cylinder 30, known to those skilled in the art as direct fuel injection. Fuel injector 66 delivers liquid fuel proportional to the pulse width of controller 12. Fuel is delivered to fuel injector 66 by a fuel system (not shown) that includes a fuel tank, a fuel pump, and a fuel rail (not shown). In one example, a two-stage, high-pressure fuel system may be used to generate higher fuel pressure.

[0013] Additionally, the intake manifold 44 is shown communicating with the turbocharger compressor 162 and the engine air intake 42. In other examples, the compressor 162 may be a supercharger compressor. The shaft 161 mechanically couples the turbocharger turbine 164 to the turbocharger compressor 162. The optional electronic throttle 62 adjusts a position of the throttle plate 64 to control airflow from the compressor 162 to the intake manifold 44. The pressure in the boost chamber 45 may be related to a throttle inlet pressure because the inlet of the throttle 62 is located within the boost chamber 45. The throttle outlet is located within the intake manifold 44. In some examples, the throttle 62 and the throttle plate 64 may be positioned between the intake valve 52 and the intake manifold 44 such that the throttle 62 is a port throttle.Wastegate 163 can be adjusted via controller 12 to allow exhaust gases to selectively bypass turbine 164 to control the speed of compressor 162. Air cleaner 43 cleans air entering engine air intake 42.

[0014] A distributorless ignition system 88 provides an ignition spark to the combustion chamber 30 in response to the controller 12 via the spark plug 92. A wideband lambda (Universal Exhaust Gas Oxygen - UEGO) sensor 126 is shown coupled to the exhaust manifold 48, which is upstream of the catalytic converter 70. Alternatively, the UEGO sensor 126 may be replaced with a binary lambda sensor.

[0015] In one example, the catalyst 70 may include multiple catalyst modules. In another example, multiple emission control devices, each including multiple modules, may be used. In one example, the catalyst 70 may be a three-way catalyst.

[0016] The control 12 is in Fig. 1 as a conventional microcomputer including: a microprocessor unit 102, input / output channels 104, read-only memory 106 (e.g., non-volatile memory), random access memory 108, keep-alive memory 110, and a conventional data bus.The controller 12 is illustrated as receiving various signals from sensors coupled to the internal combustion engine 10, in addition to those signals previously discussed, including: the engine coolant temperature (ECT) from temperature sensor 112 coupled to a cooling sleeve 114; a position sensor 134 coupled to an accelerator pedal 130 to detect the force applied by a human driver 132; a position sensor 154 coupled to the brake pedal 150 to detect the force applied by a human driver 132; an engine manifold pressure (MAP) measurement from pressure sensor 122 coupled to the intake manifold 44; an engine position sensor from a Hall effect sensor 118 that detects the position of the crankshaft 40; a measurement of the air mass entering the combustion engine from sensor 120; and a measurement of the throttle position from sensor 68.Atmospheric pressure may also be sensed for processing by controller 12 (sensor not shown). In a preferred aspect of the present description, engine position sensor 118 generates a predetermined number of evenly spaced pulses with each revolution of the crankshaft, from which engine speed (RPM) can be determined.

[0017] Controller 12 can also receive human driver inputs from input device 140. Input device 140 can include a display panel and a keyboard or virtual keyboard. A human can input requests related to the vehicle's driving mode via input device 140.

[0018] During operation, each cylinder in the internal combustion engine 10 typically undergoes a four-stroke cycle: The cycle includes the intake stroke, the compression stroke, the power stroke, and the exhaust stroke. During the intake stroke, the exhaust valve 54 generally closes and the intake valve 52 opens. Air is introduced into the combustion chamber 30 via the intake manifold 44, and the piston 36 moves toward the bottom of the cylinder to increase the volume in the combustion chamber 30. The position where the piston 36 is near the bottom of the cylinder and at the end of its stroke (e.g., when the combustion chamber 30 is at its largest volume) is commonly referred to by those skilled in the art as bottom dead center (BDC).

[0019] During the compression stroke, the intake valve 52 and the exhaust valve 54 are closed. The piston 36 moves toward the cylinder head to compress the air within the combustion chamber 30. The point at which the piston 36 is at the end of its stroke and closest to the cylinder head (e.g., when the combustion chamber 30 is at its smallest volume) is commonly referred to by those skilled in the art as top dead center (TDC). In a process referred to below as injection, fuel is introduced into the combustion chamber. In a process referred to below as ignition, the injected fuel is ignited by known ignition means, such as the spark plug 92, resulting in combustion.

[0020] During the power stroke, the expanding gases push the piston 36 back to BDC. The crankshaft 40 converts piston motion into rotating shaft torque. Finally, during the exhaust stroke, the exhaust valve 54 opens to release the combusted air-fuel mixture to the exhaust manifold 48, and the piston returns to TDC. It should be noted that the foregoing is merely an example, and that the timing for opening and / or closing the intake and exhaust valves may vary, such as to provide positive or negative valve overlap, late intake valve closing, or various other examples.

[0021] Fig. 2A is a block diagram of a vehicle 225 including a drivetrain or transmission 200. The drivetrain of Fig. 2A includes the Fig. 1. The powertrain 200 is shown to include the vehicle system controller 255, the engine controller 12, the electric machine controller 252, the transmission controller 254, the energy storage device controller 253, and the brake controller 250. The controllers may communicate via the Controller Area Network (CAN) 299. Each of the controllers may provide information to other controllers, such as torque output limits (e.g., the torque output of the device or component is controlled not to be exceeded), torque input limits (e.g., the torque input of the device or component is controlled not to be exceeded), torque output of the controlled device, sensor and actuator data, diagnostic information (e.g.,Information regarding a degraded transmission, information regarding a degraded internal combustion engine, information regarding a degraded electric machine, information regarding degraded brakes). Further, the vehicle system controller 255 may provide commands to the internal combustion engine controller 12, the electric machine controller 252, the transmission controller 254, and the brake controller 250 to satisfy driver input requests and other requests based on vehicle operating conditions.

[0022] For example, in response to a driver releasing an accelerator pedal and the vehicle speed, the vehicle system controller 255 may request a desired wheel torque or wheel power level to provide a desired degree of vehicle deceleration. The desired wheel torque may be provided by the vehicle system controller 255 requesting a first braking torque from the electric machine controller 252 and a second braking torque from the braking controller 250, wherein the first and second torques provide the desired braking torque at the vehicle wheels 216.

[0023] In other examples, the distribution of control of powertrain devices may be distributed differently than in Fig. 2A. For example, a single controller may take the place of the vehicle system controller 255, the engine controller 12, the electric machine controller 252, the transmission controller 254, and the brake controller 250. Alternatively, the vehicle system controller 255 and the engine controller 12 may be a single unit, while the electric machine controller 252, the transmission controller 254, and the brake controller 250 are standalone controllers.

[0024] In this example, the powertrain 200 may be driven by the internal combustion engine 10 and the electric machine 240. The internal combustion engine 10 may be connected to an internal combustion engine starting system that is Fig. 1, via a belt integrated starter / generator (BISG) 219 or via a powertrain integrated starter / generator (ISG) 240, also known as an electric motor / generator. The powertrain ISG 240 (e.g., high-voltage electric machine (operating at greater than 30 volts)) may also be referred to as an electric machine, an electric motor, and / or a generator. Further, the torque of the internal combustion engine 10 may be adjusted via a torque actuator 204, such as a fuel injector, a throttle, etc.

[0025] The BISG is mechanically coupled to the internal combustion engine 10 via the belt 231. The BISG can be coupled to the crankshaft 40 or a camshaft (e.g., 51 or 53). The BISG can be operated as an electric motor when supplied with electrical energy via the electrical energy storage device 275. The BISG can be operated as a generator, which supplies the electrical energy storage device 275 with electrical energy.

[0026] Engine output torque may be transmitted through flywheel 215 to an input or first side of the powertrain disconnect clutch 235. The disconnect clutch 236 may be electrically or hydraulically actuated. The downstream or second side 234 of the disconnect clutch 236 is shown mechanically coupled to the ISG input shaft 237.

[0027] The ISG 240 is operable to provide torque to the drive 200 or to convert driveline torque into electrical energy to be stored in the electrical energy storage device 275. The ISG 240 is in electrical communication with the energy storage device 275. The ISG 240 has a higher output torque capacity than the starter 96, which is Fig. 1, or the BISG 219. Further, the ISG 240 directly drives the driveline 200 or is directly driven by the driveline 200. The ISG 240 rotates at the same speed as the driveline 200. The electrical energy storage device 275 (e.g., high-voltage battery or power source) may be a battery, capacitor, or inductor. The downstream side of the ISG 240 is mechanically coupled to the impeller 285 of the torque converter 206 via the shaft 241. The upstream side of the ISG 240 is mechanically coupled to the disconnect clutch 235. The ISG 240 may provide positive torque or negative torque to the driveline 200 by operating as an electric motor or a generator, as commanded by the electric machine controller 252.

[0028] The torque converter 206 includes a turbine 286 for outputting torque to an input shaft 270. The transmission input shaft 270 mechanically couples the torque converter 206 to the automatic transmission 208. The torque converter 206 also includes a torque converter bypass clutch (TCC) 212. Torque is transferred directly from the impeller 285 to the turbine 286 when the TCC is locked. The TCC is electrically operated by the controller 254. Alternatively, the TCC may be hydraulically locked. In one example, the torque converter may be referred to as a component of the transmission.

[0029] When the torque converter clutch 212 is fully disengaged, the torque converter 206 transfers engine torque to the automatic transmission 208 via a fluid transfer between the torque converter turbine 286 and the torque converter impeller 285, enabling torque increase. Conversely, when the torque converter clutch 212 is fully engaged, the engine output torque is transferred directly to an input shaft 270 of the transmission 208 via the torque converter clutch. Alternatively, the torque converter clutch 212 may be partially engaged, allowing adjustment of the amount of torque directly delivered to the transmission.The transmission controller 254 may be configured to adjust the amount of torque transmitted by the torque converter 212 by adjusting the torque converter lock-up clutch in response to various engine operating conditions or based on a driver-based engine operating request.

[0030] The torque converter 206 also includes the pump 283, which pressurizes fluid to operate the release clutch 236, the forward clutch 210, and the transmission clutches 211. The pump 283 is driven by the impeller 285, which rotates at the same speed as the ISG 240.

[0031] The automatic transmission 208 includes transmission clutches (e.g., gears 1-10) 211 and the forward clutch 210. The automatic transmission 208 is a fixed-ratio transmission. The transmission clutches 211 and the forward clutch 210 can be selectively engaged to change a ratio of an actual total number of revolutions of the input shaft 270 to an actual total number of revolutions of the wheels 216. The transmission clutches 211 can be engaged or disengaged by adjusting fluid supplied to the clutches via shift control solenoid valves 209. Torque output from the automatic transmission 208 can also be transmitted to the wheels 216 to propel the vehicle via the output shaft 260. Specifically, the automatic transmission 208 may transmit input drive torque to the input shaft 270 in response to a driving condition of the vehicle before transmitting output drive torque to the wheels 216.The transmission controller 254 selectively activates or engages the TCC 212, the transmission clutches 211, and the forward clutch 210. The transmission controller also selectively deactivates or disengages the TCC 212, the transmission clutches 211, and the forward clutch 210.

[0032] Furthermore, a frictional force may be applied to the wheels 216 by applying the friction wheel brakes 218. In one example, the friction wheel brakes 218 may be applied in response to the driver pressing their foot on a brake pedal (not shown) and / or in response to instructions in the brake controller 250. Further, the brake controller 250 may apply the brakes 218 in response to information and / or requests from the vehicle system controller 255. Likewise, a frictional force on the wheels 216 may be reduced by releasing the wheel brakes 218 in response to the driver removing their foot from a brake pedal, as well as in response to instructions from the brake controller and / or instructions and / or information from the vehicle system controller. For example, the vehicle brakes may apply a frictional force to the wheels 216 via the controller 250 as part of an automated engine stop procedure.

[0033] The vehicle system controller 255 may also communicate vehicle suspension settings to the suspension controller 280. The suspension of the vehicle 225 may be adjusted to critically damp, over-damp, or under-damp the vehicle suspension via variable dampers 281.

[0034] In response to a request to accelerate the vehicle 225, the vehicle system controller may receive a driver demand torque or power request from an accelerator pedal or other device. The vehicle system controller 255 then allocates a portion of the requested driver demand torque to the engine and the remaining portion to the ISG 240 or BISG 219. The vehicle system controller 255 requests the engine torque from the engine controller 12 and the ISG torque from the electric machine controller 252. If the ISG torque plus the engine torque is less than a transmission input torque limit (e.g., a threshold not to be exceeded), the torque is delivered to the torque converter 206, which then provides at least a portion of the requested torque to the transmission input shaft 270.The transmission controller 254 selectively locks the torque converter clutch 212 and engages gears via the transmission clutches 211 in response to shift schedules and TCC lock-up schedules, which may be based on input shaft torque and vehicle speed. Under some conditions, when it is desired to charge the electrical energy storage device 275, a boost torque (e.g., a negative ISG torque) may be required while a non-zero driver demand torque is present. The vehicle system controller 255 may request increased engine torque to overcome the boost torque to match the driver demand torque.

[0035] In response to a request to decelerate the vehicle 225 and provide regenerative braking, the vehicle system controller may provide a negative desired wheel torque based on the vehicle speed and the brake pedal position. The vehicle system controller 255 then allocates a portion of the negative desired wheel torque to the ISG 240 (e.g., desired driveline wheel torque) and / or engine 10 and the remaining portion to the friction brakes 218 (e.g., desired friction brake wheel torque). Further, the vehicle system controller may notify the transmission controller 254 that the vehicle is in a regenerative braking mode, so the transmission controller 254 shifts gears 211 based on a unique shift schedule to increase regeneration efficiency.The ISG 240 supplies negative torque to the transmission input shaft 270, but the negative torque provided by the ISG 240 may be limited by the transmission controller 254, which outputs a limit on the negative torque of the transmission input shaft (e.g., a threshold not to be exceeded). Further, the negative torque of the ISG 240 may be limited (e.g., limited to less than a negative torque threshold) based on the operating conditions of the electrical energy storage device 275, by the vehicle system controller 255, or the electric machine controller 252. The internal combustion engine 10 may also provide negative torque by ceasing fuel delivery to the engine cylinders.Engine cylinders may be deactivated, with intake and exhaust valves opening and closing during engine rotation, or with the intake and exhaust valves held closed for one or more engine cycles while the engine rotates. Any portion of a desired negative wheel torque that cannot be provided by the engine 10 and / or ISG 240 due to transmission or ISG limitations may be allocated to the friction brakes 218, such that the desired wheel torque is provided by a combination of the negative wheel torque from the friction brakes 218 and the ISG 240.

[0036] Accordingly, the torque control of the various drive components may be monitored by the vehicle system controller 255 with local torque control for the engine 10, the transmission 208, the electric machine 240, and the brakes 218 provided via the engine controller 12, the electric machine controller 252, the transmission controller 254, and the brake controller 250.

[0037] As one example, engine torque output may be controlled by adjusting a combination of spark timing, fuel pulse width, fuel pulse timing, and / or air charge by controlling throttle opening and / or valve timing, valve lift, and boost pressure for turbocharged or supercharged internal combustion engines. In the case of a diesel engine, controller 12 may control engine torque output by controlling a combination of fuel pulse width, fuel pulse timing, and air charge. In all cases, engine control may be performed on a cylinder-by-cylinder basis to control engine torque output.

[0038] The electric machine controller 252 may control the torque output and electrical energy generation from the ISG 240 by adjusting the current flowing to and from field and / or armature windings of the ISG, as is known in the art.

[0039] The transmission controller 254 receives the transmission input shaft position via position sensor 271. The transmission controller 254 may convert the transmission input shaft position to an input shaft speed by differentiating a signal from the position sensor 271 or counting a number of known angular distance pulses for a predetermined time interval. The transmission controller 254 may receive the transmission output shaft torque from the torque sensor 272. Alternatively, the sensor 272 may be a position sensor or a torque and position sensor. If the sensor 272 is a position sensor, the controller 254 may count shaft position pulses over a predetermined time interval to determine the transmission output shaft speed. The transmission controller 254 may also differentiate a transmission output shaft speed to determine the transmission output shaft acceleration.The transmission controller 254, the engine controller 12, and the vehicle system controller 255 may also receive additional transmission information from the sensors 277, which may include, but are not limited to, pump output line pressure sensors, transmission hydraulic pressure sensors (e.g., transmission clutch fluid pressure sensors), ISG temperature sensors, and BISG temperatures and ambient temperature sensors.

[0040] The brake controller 250 receives wheel speed information via the wheel speed sensor 221 and braking requests from the vehicle system controller 255. The brake controller 250 may also receive brake pedal position information from the brake pedal sensor 154 located in Fig. 1, directly or via CAN 299. The brake controller 250 may provide braking in response to a wheel torque command from the vehicle system controller 255. The brake controller 250 may also provide anti-lock and vehicle stability braking to enhance vehicle braking and stability. As such, the brake controller 250 may provide a wheel torque limit (e.g., a negative wheel torque threshold not to be exceeded) to the vehicle system controller 255 so that negative ISG torque does not cause the wheel torque limit to be exceeded. For example, if the controller 250 outputs a negative wheel torque limit of 50 Nm, the ISG torque is adjusted to provide less than 50 Nm (e.g., 49 Nm) of negative torque at the wheels, including consideration of the transmission gearing.

[0041] Now, with reference to Fig. 2B, an alternative power transmission or drive train 200 is shown. The power transmission from Fig. 2B contains many of the same components as in Fig. 2A. Components in Fig. 2B, which has the same numerical values ​​as in Fig. 2A are the same components. Furthermore, the same components operate in the same manner. Therefore, descriptions of similar components may be omitted for the sake of brevity.

[0042] The powertrain 200 includes the internal combustion engine 10, which is mechanically coupled to the ISG 240 via shaft 237. The ISG 240 is mechanically coupled to a dual-clutch transmission (DCT) 285 via shaft 241. The DCT 285 includes a first clutch 281, a second clutch 282, and a gear case 283. The DCT 285 outputs torque to the shaft 260 to deliver torque to the vehicle wheels 216. The transmission controller selectively opens and closes the first clutch 281 and the second clutch 282 to shift the DCT 285.

[0043] Now, with reference to Fig. 2C shows an example of an alternative power transmission 200. The power transmission from Fig. 2C includes many of the same components as in Fig. 2A. Components in Fig. 2C, which has the same numerical values ​​as in Fig. 2A are the same components. The powertrain 200 includes the combustion engine 10 and the torque actuator 204 as shown in Fig. 1. The engine 10 provides torque to the planetary gear set 233, and the generator 228 operates in a speed control mode to control the delivery of engine torque to the single-stage shifting system 276. The output from the generator 228 provides electrical energy to the energy storage device 275 and the engine 273. The electrical energy storage device 275 may supply electrical power to the engine 273 via the variable voltage controller 279 when the engine 10 is not operating. The electrical energy storage device may be a battery, a capacitor, or other electrical energy storage device. The electric motor 273 may also operate in a generator mode for regenerative braking.Torque from the internal combustion engine 10 and electric motor 273 may be combined in the single-stage switching system 276 to provide torque to the vehicle wheels 216 via a mechanical power path. The controller 12 controls the operation of the internal combustion engine 10, the generator 228, and the electric motor 273 to adjust the power delivered to the vehicle wheels 216. Thus, the power transmission from . Fig. 2C no transmission with several fixed gear ratios for delivering power from the combustion engine and electric motor to the vehicle wheels.

[0044] Now, with reference to Fig. 3A, an exemplary multi-cylinder internal combustion engine 10 is shown, illustrating the deactivation of the intake and exhaust valve actuators. The internal combustion engine includes cylinders and associated components as shown in Fig. 1. The internal combustion engine 10 includes eight cylinders 310. Each of the eight cylinders is numbered, and the cylinder numbers are included in the cylinders. The fuel injectors 66 selectively supply fuel to each of the cylinders that are activated (e.g., combusting fuel during an engine cycle). Cylinders 1-8 may be selectively deactivated to improve engine fuel efficiency when less than the full torque capacity of the engine is demanded. Further, intake and exhaust valves of selected cylinders may be deactivated to change pumping characteristics of the engine. For example, cylinders 2, 3, 5, and 8 (e.g., a fixed pattern of deactivated cylinders) may be deactivated during an engine cycle (e.g.,Two revolutions for a four-stroke engine) may be deactivated and may be deactivated for a plurality of engine cycles while engine speed and load are constant or vary slightly. During another engine cycle, a second fixed pattern of cylinders 1, 4, 6, and 7 may be deactivated. Further, other patterns of cylinders may be selectively deactivated based on vehicle operating conditions. Additionally, engine cylinders may be deactivated such that a fixed pattern of cylinders is not deactivated over a plurality of engine cycles. Instead, cylinders that are deactivated may change from one engine cycle to the next engine cycle.

[0045] The internal combustion engine 10 may also include deactivating valve actuators 58 and 59. The deactivating valve actuators make it possible to control whether air is introduced into each individual cylinder on a cycle-by-cycle basis. During some internal combustion engine cycles, when air is introduced into a cylinder, fuel may be added to the air and an ignition spark introduced to produce power during that event. The burned gases may then be exhausted into the adjacent exhaust manifold. During other internal combustion engine cycles, when air is introduced, no fuel may be added and no combustion may occur. The fresh air may then be exhausted into the adjacent exhaust manifold. During other cycles, the intake and exhaust valves may be deactivated so that no air is introduced or exhausted.

[0046] Each cylinder includes variable intake valve operators 59 and variable exhaust valve operators 58. An internal combustion engine cylinder can be deactivated by its variable intake valve operators 59 and variable exhaust valve operators, which keep the cylinder's intake and exhaust valves closed throughout an entire cylinder cycle. An internal combustion engine cylinder can be activated by its variable intake valve operators 59 and variable exhaust valve operators 58, which open and close the cylinder's intake and exhaust valves during a cylinder cycle. The internal combustion engine 10 includes a first cylinder bank 304 including four cylinders, 1, 2, 3, and 4. The internal combustion engine 10 also includes a second cylinder bank 302 including four cylinders, 5, 6, 7, and 8. The cylinders of each bank can be active or deactivated during an internal combustion engine cycle.

[0047] Now, with reference to Fig. 3B, an exemplary multi-cylinder internal combustion engine 10 is shown, illustrating the deactivation of the intake and exhaust valve actuators. The internal combustion engine includes cylinders and associated components as shown in Fig. 1. The internal combustion engine 10 includes four cylinders 310. Each of the four cylinders is numbered, and the cylinder numbers are included in the cylinders. The fuel injectors 66 selectively supply fuel to each of the cylinders that are activated (e.g., combusting fuel during a cycle of the internal combustion engine, with intake and exhaust valves opening and closing during a cycle of the cylinder that is active).

[0048] The internal combustion engine 10 may also include deactivating valve actuators 58 and 59. The deactivating valve actuators make it possible to control whether air is introduced into each individual cylinder on a cycle-by-cycle basis. During some internal combustion engine cycles, when air is introduced into a cylinder, fuel may be added to the air and an ignition spark introduced to produce power during that event. The burned gases may then be exhausted into the adjacent exhaust manifold. During other internal combustion engine cycles, when air is introduced, no fuel may be added and no combustion may occur. The fresh air may then be exhausted into the adjacent exhaust manifold. During other cycles, the intake and exhaust valves may be deactivated so that no air is introduced or exhausted.

[0049] Cylinders 1-4 may be selectively deactivated (e.g., during an engine cycle in which intake and exhaust valves are kept closed, not burning fuel, for an entire cycle of the deactivated cylinder) to improve engine fuel economy when less than the engine's full torque capacity is demanded. For example, cylinders 2 and 3 (e.g., a fixed pattern of deactivated cylinders) may be deactivated during a plurality of engine cycles (e.g., two revolutions for a four-stroke engine). During another engine cycle, a second fixed pattern of cylinders 1 and 4 may be deactivated over a plurality of engine cycles. Further, other patterns of cylinders may be selectively deactivated based on vehicle operating conditions.Additionally, engine cylinders can be deactivated so that a fixed pattern of cylinders is not deactivated across multiple engine cycles. Instead, deactivated cylinders can change from one engine cycle to the next. In this way, the deactivated engine cylinders can rotate or change from one engine cycle to the next.

[0050] The internal combustion engine 10 includes a single cylinder bank 350 containing four cylinders 1-4. The cylinders of the individual bank can be active or deactivated during an internal combustion engine cycle. Each cylinder includes variable intake valve operators 59 and variable exhaust valve operators 58. An internal combustion engine cylinder can be deactivated by its variable intake valve operators 59 and variable exhaust valve operators 58, which keep the cylinder's intake and exhaust valves closed during a cylinder cycle. An internal combustion engine cylinder can be activated by its variable intake valve operators 59 and variable exhaust valve operators 58, which open and close the cylinder's intake and exhaust valves during a cylinder cycle.

[0051] Thus, the systems Fig. 1-3B provides a system comprising: an internal combustion engine; an electric machine coupled to the internal combustion engine; a transmission coupled to the electric machine; and a vehicle system controller having executable instructions stored in non-volatile memory to operate internal combustion engine cylinders with valves opening and closing and without fuel in response to a torque capacity of the electric machine being less than a desired braking torque in the powertrain, and instructions stored in non-volatile memory to operate internal combustion engine cylinders with valves closed over a plurality of internal combustion engine cycles and without fuel in response to the torque capacity of the electric machine being greater than the desired braking torque for the powertrain.The system further includes a clutch for disconnecting the transmission between the engine and the electric machine. The system includes the stepped transmission being a dual-clutch transmission. The system further includes additional instructions for determining whether a speed of a vehicle is outside a range of vehicle speeds. In other examples, the engine may be coupled to a planetary gear set, wherein the planetary gear set is coupled to a generator. The generator may be coupled to a transmission case along with an electric motor. The transmission case may be coupled to vehicle tires.

[0052] Now, with reference to Fig. 4 shows an operating sequence of the hybrid power transmission. The sequence of Fig. 4 may be made in accordance with the procedure Fig. 5 together with or in connection with the system Fig. 1-3B. The Fig. 4 shown courses occur simultaneously and are aligned in time.

[0053] The first course from above in Fig. Figure 4 is a plot of the desired transmission input shaft torque versus time. The vertical axis represents the desired transmission input shaft torque. The desired transmission input shaft torque is zero on the vertical plane, which corresponds to the horizontal axis. The desired transmission shaft torque is positive and increases in the direction of the vertical axis arrow, pointing upwards. The desired transmission shaft torque is negative and decreases in the direction of the vertical axis arrow, pointing downwards. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure. The horizontal line 402 represents a negative torque capacity of an electric motor in the powertrain (e.g., 240 from Fig. 2A and Fig. 2B) during the present vehicle operating conditions. The electric motor has no capacity to provide negative torques of a magnitude greater than (e.g., desired transmission input torque traces below horizontal line 402) on horizontal line 402.

[0054] The second course from the top in Fig. 4 is a plot of a state of the vehicle's sport operating mode versus time. The vehicle is in a sport operating mode when the trace is at a higher level near the vertical axis arrow. The vehicle is not in a sport mode when the trace is at a lower level near the horizontal axis. When entering and exiting the sport operating mode, several vehicle operating parameters may be changed. For example, in sport mode, the vehicle's suspension characteristics may be changed. In particular, damping of the vehicle's suspension may be adjusted to overdamp (e.g., stiffen) in response to entering the sport mode from a nominal vehicle operating mode. On the other hand, in a touring or nominal suspension mode, the vehicle's dampers may be adjusted such that the vehicle's suspension is underdamped.Sport mode may also include powertrain adjustments such as shifting transmission gears at higher vehicle speeds compared to when the vehicle is not in a sport mode. Also, engine ignition timing may be advanced, and a throttle transfer function that translates throttle position into driver-demand torque may increase engine torque at lower throttle inputs than when the vehicle is not operating in a sport mode. Furthermore, when entering sport mode from touring mode, valve timing may be adjusted. Thus, vehicle performance may be increased when entering sport mode compared to operation in other vehicle modes.

[0055] The third course from the top in Fig. Figure 4 is a graph of the engine fuel delivery state versus time. The vertical axis represents the engine fuel delivery state, and fuel is delivered to the engine when the trace is at a higher level near the vertical axis arrow. Fuel is not delivered to the engine when the trace is at a lower level near the horizontal axis.

[0056] The fourth course from the top in Fig. Figure 4 is a plot of the number of internal combustion engine cylinders with active poppet valves versus time. Cylinder poppet valves are active when they open and close during one internal combustion engine cycle. The vertical axis represents the actual total number of internal combustion engine cylinders with active poppet valves, and the actual total number of active poppet valves is listed along the vertical axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

[0057] The fifth course from the top in Fig. Figure 4 is a graph of the engine rotation state versus time. The vertical axis represents the engine rotation state, and the engine is rotating when the trace is at a higher level near the vertical axis arrow. The engine is not rotating and is stopped when the trace is near the horizontal axis. The horizontal axis represents time, and time increases from the left side of the figure to the right side of the figure.

[0058] The sixth course from the top in Fig. Figure 4 is a plot of vehicle speed versus time. The vertical axis represents vehicle speed, and vehicle speed increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the figure to the right side. The horizontal line 404 represents a vehicle speed above which the vehicle's internal combustion engine must not stop rotating.

[0059] At time T0, the vehicle is at an average speed below threshold speed 504, and the desired transmission input torque is positive. The vehicle is in sport mode, and fuel is being delivered to the internal combustion engine. The internal combustion engine operates with eight cylinders featuring active poppet valves that admit air into the cylinders and exhaust combustion byproducts from the internal combustion engine cylinders. The internal combustion engine is also rotating.

[0060] At time T1, the desired transmission input shaft torque transitions from positive torque to negative torque (not shown) in response to a reduction in driver demand torque. The desired transmission input shaft torque is a small negative value that is within the electric motor's ability to provide, as indicated by trace 501 located above horizontal line 502. The vehicle remains in sport mode, and the vehicle speed is less than threshold 504. Combustion in the engine cylinders is not desired, so fuel efficiency may be improved. The judgment that combustion is not desired may be based on the vehicle speed and the low driver demand torque.Fuel delivery to the engine is terminated to suspend combustion in the engine cylinders shortly after the driver demand torque is reduced and the actual total number of cylinders with active poppet valves decreases from eight to zero. The engine continues to rotate. Thus, in response to the negative transmission input torque demand and the vehicle being in a sport mode, the termination of combustion in an internal combustion engine, rotation of the engine, and reduction of the actual total number of cylinders with active poppet valves are provided.

[0061] At time T2, the desired transmission input shaft torque transitions from a negative value to a positive value in response to an increase in driver demand torque (not shown). Combustion in the engine is restarted by activating fuel delivery to the engine as indicated by the fuel delivery state transitioning to a higher stage. The actual total number of cylinders with activated poppet valves also increases from zero to eight, allowing combustion in the engine cylinders to restart. Because the engine has continued to rotate, the engine is started quickly without over-cranking the engine. Vehicle speed begins to increase in response to the increasing desired transmission input shaft torque and the reactivation of combustion in the engine. The vehicle remains in a sport mode.After the vehicle reaches a steady speed, the torque required to maintain speed can be reduced. The desired transmission input shaft torque decreases, and the number of active cylinders decreases from eight to four between time T2 and time T3.

[0062] At time T3, the desired transmission input shaft torque again transitions from positive torque to negative torque in response to a reduction in driver demand torque (not shown). The desired transmission input shaft torque is a large negative value that is not within the electric motor's capability to provide, as indicated by trace 501 located below horizontal line 502. The vehicle remains in sport mode, and the vehicle speed is less than threshold 504. Combustion in the engine cylinders is not desired, so fuel efficiency may be improved. Fuel delivery to the engine is terminated to suspend combustion in the engine cylinders shortly after the driver demand torque is reduced and the actual total number of cylinders with active poppet valves increases from four to six.The total number of active cylinders with active poppet valves only increases by two cylinders. This is because the engine can provide increased braking torque when the engine cylinders are operated with activated poppet valves. Pumping losses of the engine are increased compared to when the engine is rotated when all cylinder poppet valves of the engine are deactivated and held in a closed position while the engine rotates. Thus, to increase negative braking in the powertrain, two engine cylinders are operated with active poppet valves while the fuel flow to the engine is stopped and the engine continues to rotate, as indicated by the engine rotation state.In this way, terminating combustion in an internal combustion engine, rotating the internal combustion engine, operating some cylinders with active poppet valves, and operating some cylinders with deactivated poppet valves as shown in response to the negative transmission input torque demand and the vehicle being in a sport mode is provided.

[0063] At time T4, the desired transmission input shaft torque transitions from a negative value to a positive value in response to an increase in driver demand torque (not shown). Combustion in the engine is restarted by activating fuel delivery to the engine as indicated by the fuel delivery state transitioning to a higher stage. The actual total number of cylinders with activated poppet valves also increases from six to eight, allowing combustion in the engine cylinders to restart. Because the engine has continued to rotate, the engine is started quickly without having to overcrank the engine. Vehicle speed begins to increase in response to the increasing desired transmission input shaft torque and the reactivation of combustion in the engine. The vehicle remains in a sport mode.

[0064] Between time T4 and time T5, the human driver transitions the vehicle from Sport mode to a nominal mode (e.g., Touring) to reduce vehicle power. By reducing vehicle power, it may be possible to improve the vehicle's fuel efficiency and ride quality on less smooth roads. The vehicle transitions from Sport mode to a nominal mode as indicated by the vehicle's Sport mode selection state.

[0065] At time T5, the desired transmission input shaft torque again transitions from positive torque to negative torque in response to a reduction in driver demand torque (not shown). The desired transmission input shaft torque is a negative value that is within the electric motor's ability to provide, as indicated by trace 501 located above horizontal line 502. The vehicle remains out of sport mode, and the vehicle speed is less than threshold 504. Combustion in the engine cylinders is not desired, so fuel efficiency may be improved. Fuel delivery to the engine is terminated to suspend combustion in the engine cylinders shortly after the driver demand torque is reduced and the actual total number of cylinders with active poppet valves decreases from eight to zero.However, during this period of low driver demand torque, the engine stops rotating. By stopping engine rotation and deactivating the cylinder poppet valves in a closed state, sending fresh air to the engine catalyst can be avoided, allowing the catalyst to remain in an efficient operating state. Thus, in response to the negative transmission input torque demand and the vehicle not being in a sport mode, stopping combustion in an engine, stopping engine rotation, and stopping poppet valve operation in the engine cylinders is provided.

[0066] At time T6, the desired transmission input shaft torque transitions from a negative value to a positive value in response to an increase in driver demand torque (not shown). Combustion in the engine is restarted by enabling fuel delivery to the engine, as indicated by the fuel delivery state transitioning to a higher stage. The actual total number of cylinders with activated poppet valves also increases from zero to eight, allowing combustion in the engine cylinders to restart.

[0067] Because the engine's rotation has been stopped, engine start-up time may increase, but fuel consumption may be reduced. Vehicle speed begins to increase in response to the increasing desired transmission input shaft torque and the reactivation of combustion in the engine. The vehicle remains out of Sport mode.

[0068] In this way, a powertrain can transition between various fuel delivery states, cylinder deactivation modes, and engine rotation states in response to a desired transmission input shaft torque, vehicle speed, and vehicle mode selection. Furthermore, the total number of cylinders with active poppet valves can be determined based on the requested transmission input shaft torque and the ability of an electric motor in the powertrain to provide the requested transmission input shaft torque.

[0069] Now, with reference to Fig. 5 discloses a method for operating a hybrid vehicle. The method of Fig. 5 can be integrated into the system as executable instructions stored in non-volatile memory Fig. 1-3B may be included. In addition, sections of the procedure from Fig. 5 actions that are caused by the Fig. 1, Fig. 2A, Fig. 2B and Fig. 2C shown controller 12 to transfer a state of a device or actuator to the real world.

[0070] At 504, method 500 judges whether negative torque is requested in the driveline and no combustion is requested in the engine. Combustion in the engine may not be requested and negative torque in the driveline may be requested when a vehicle is moving at a threshold speed and a driver demand torque or requested tire torque is less than a threshold. By requesting negative torque in the driveline, the driveline may provide braking to reduce vehicle speed. Further, by terminating combustion in the engine, vehicle fuel consumption may be reduced. If method 500 judges that negative torque is requested in the driveline and no combustion is requested in the engine, the answer is yes and method 500 proceeds to 506.Otherwise, the answer is no and procedure 500 proceeds to the end.

[0071] At 506, method 500 judges whether or not the vehicle is in a sport mode. If the vehicle is in a sport mode, the vehicle operating parameters may be adjusted to improve vehicle performance as described above. Method 500 may judge that the vehicle is in a sport mode based on a state of a byte or word in memory. If method 500 judges that the vehicle is in a sport mode, the answer is yes and method 500 proceeds to 520. Otherwise, the answer is no and method 500 proceeds to 508.

[0072] At 508, method 500 judges whether the vehicle speed of the vehicle is outside a range in which stopping the rotation of the engine is permitted. In one example, method 500 determines that the vehicle is outside a speed range in which stopping the rotation of the engine is permitted if the vehicle speed is greater than a threshold speed. If method 500 judges that the vehicle is outside a speed range in which stopping the rotation of the engine is permitted, the answer is yes, and method 500 proceeds to 520. Otherwise, the answer is no, and method 500 proceeds to 510.

[0073] At 510, method 400 assesses whether or not an electric machine in the vehicle's powertrain has the capability to provide a desired negative torque in the powertrain for powertrain braking, according to the prevailing vehicle operating conditions, including battery state of charge. In one example, method 500 determines the capability of the electric machine to provide braking torque in the powertrain that decelerates the vehicle at a desired speed. If method 500 assesses that the electric machine has torque capacity to provide the desired amount of powertrain braking, the answer is yes, and method 500 proceeds to 530. Otherwise, the answer is no, and method 500 proceeds to 512.

[0074] At 512, method 500 resumes engine rotation by maintaining the engine's coupling to the powertrain and the vehicle tires. For example, the TCC may remain closed and the transmission clutches may be closed to maintain a connection between the engine and the tires. However, if engine rotation is stopped, the engine is restarted. Method 500 proceeds to 514.

[0075] At 514, method 500 determines an actual total number of engine cylinders to be deactivated with poppet valves in a closed position while the engine rotates through an engine cycle. By deactivating the engine cylinders with the cylinder's poppet valves closed, the engine's pumping power may be reduced, so that braking in the powertrain may be less while the engine rotates. In one example, method 500 determines a negative amount of torque the engine can produce by deactivating one or more engine cylinders and keeping intake and exhaust poppet valves closed over a cylinder cycle.The negative amount of torque produced by a cylinder when its intake and exhaust poppet valves are held closed with no combustion in the cylinder may be empirically determined and stored in controller memory via a table or function indexed by engine speed and temperature. Alternatively, engine speed and temperature may be inputs to an empirically determined function that outputs a negative amount of torque produced by a cylinder that is not combusting air and fuel during an engine cycle, where the cylinder's intake and exhaust poppet valves are also held closed throughout an engine or cylinder cycle (e.g., cylinder deactivation for deceleration (DCCO) cylinder mode).

[0076] Method 500 also determines an amount of negative torque a cylinder produces over an engine cycle when combustion in the cylinder is complete and the cylinder's intake and exhaust poppet valves open and close during a cylinder or engine cycle (e.g., cylinder mode of engine fuel shutoff during deceleration (DFSO)). The negative amount of torque produced by a cylinder when its intake and exhaust poppet valves open and close without combustion in the cylinder may be determined empirically and stored in control memory via a table or function indexed by engine speed and engine temperature.Alternatively, the engine speed and temperature can be inputs to an empirically determined function that outputs a negative amount of torque produced by a cylinder producing no air and fuel with operating poppet valves during an engine cycle (e.g., DFSO cylinder mode).

[0077] Method 500 then selects an actual total number of engine cylinders to operate in DCCO mode and an actual total number of cylinders to operate in DFSO mode to provide the requested braking torque in the driveline determined at 510. Method 500 selects cylinders to operate in DFSO mode and DCCO mode based on the engine's ability to provide braking torque closest to the desired braking torque. In one example, method 500 first determines the engine braking torque when all engine cylinders are in DCCO mode. If the requested engine braking torque is less than or equal to the engine braking torque produced when all engine cylinders are operating in DCCO mode, all engine cylinders are placed in DCCO mode.If the requested engine braking torque is greater than the engine braking torque when all engine cylinders are in DCCO mode, the engine braking torque is increased by increasing the number of engine cylinders in DFSO mode until all engine cylinders are in DFSO mode or an engine braking torque greater than the requested engine braking torque is provided. For example, if 36 Nm of engine braking torque is requested and the engine cylinders provide 3 Nm of braking torque when operating without combustion in DCCO mode and 5 Nm of braking torque when operating without combustion in DFSO mode, method 500 first determines that the engine can provide 8 * 3 = 24 Nm of braking torque when all eight engine cylinders are operating in DCCO mode.Since 24 Nm of engine braking torque is less than 36 Nm of braking torque, method 600 increases the actual total number of engine cylinders operating in DFSO mode to one that provides (7 * 3) + (1 * 5) = 26 Nm of braking torque. The number of engine cylinders operating in DFSO is increased until the actual total number of engine cylinders in DFSO mode equals six, with the remaining two cylinders of the eight-cylinder engine remaining in DCCO mode. In this way, the actual total number of engine cylinders in DCCO mode and the actual total number of engine cylinders in DFSO mode may be determined. Method 500 proceeds to 516.

[0078] At 516, method 500 adjusts fuel delivery to the cylinders to be operated in DCCO mode and the cylinders to be operated in DFSO mode. Additionally, method 500 deactivates poppet valves in cylinders operating in DCCO mode so that intake and exhaust poppet valves remain closed during a cylinder or engine cycle. Each engine cylinder is operated in DCCO mode or DFSO mode. The actual total number of engine cylinders operating in DCCO mode is determined as at 514. The actual total number of engine cylinders operating in DFSO mode is determined as at 514.The engine continues to rotate via vehicle tires, which transfer kinetic energy to the engine so that when additional engine torque is called for, the engine cylinders can be activated to begin rapidly combusting air and fuel without accelerating the engine from zero speed. Method 500 proceeds to exit.

[0079] At 530, method 500 stops the rotation of the engine. The rotation of the engine is terminated by ceasing fuel delivery to the engine and decoupling the engine from the vehicle tires. The engine may be decoupled from the vehicle tires via transmission clutches. Method 500 proceeds to exit.

[0080] At 520, method 600 assesses whether or not an electric machine in the vehicle's powertrain has the capability to provide a desired negative torque in the powertrain for powertrain braking, according to the prevailing vehicle operating conditions, including battery state of charge. In one example, method 500 determines the capability of the electric machine to provide braking torque in the powertrain that decelerates the vehicle at a desired speed. If method 500 assesses that the electric machine has torque capacity to provide the desired amount of powertrain braking, the answer is yes and method 500 proceeds to 522. Otherwise, the answer is no and method 500 proceeds to 514.

[0081] At 522, method 500 stops fuel delivery to all engine cylinders and deactivates intake and exhaust valves in a closed state so that the valves remain closed throughout an engine or cylinder cycle. The engine continues to rotate via the supply of kinetic energy from the vehicle tires to the engine, so that when additional engine torque is called for, the engine cylinders can be activated to begin rapidly combusting air and fuel without accelerating the engine from zero speed. Thus, the engine cylinders can be quickly reactivated to improve engine response time due to a change in engine torque when one or more rotating engine cylinders are not combusting air and fuel.

[0082] Thus, the procedure Fig. 5 provides a powertrain operating method comprising: adjusting fuel delivery to all engine cylinders and adjusting, via a controller, an actual total number of cylinders of an engine with operating poppet valves and an actual total number of cylinders of the engine with deactivated poppet valves in response to a desired braking torque in the powertrain during vehicle deceleration. The method further comprises rotating the engine in response to the desired braking torque in the powertrain. The method includes the poppet valves including intake and exhaust valves, and further comprising rotating the engine via power supplied via vehicle tires while fuel delivery is terminated.The method further includes adjusting the rotation of the internal combustion engine in response to a vehicle in which the internal combustion engine is not in a sport mode and an electric machine has torque capacity to provide the desired braking torque in the powertrain. The method further includes starting the internal combustion engine to rotate the internal combustion engine in response to the desired braking torque in the powertrain and insufficient negative torque capacity of an electric machine to provide the desired braking torque in the powertrain.

[0083] The procedure from Fig.5 also provides a powertrain operating method comprising: rotating an internal combustion engine and maintaining poppet valves of a cylinder of the internal combustion engine closed over a first engine cycle in response to a vehicle operating in a sport mode and an electric machine having torque capacity to provide the desired braking torque in the powertrain; and adjusting rotation of the internal combustion engine in response to the vehicle not operating in the sport mode and the electric machine having torque capacity to provide the desired braking torque in the powertrain. The method includes where the sport mode improves vehicle performance (e.g., the power output of the internal combustion engine may be increased by advancing spark timing for internal combustion engine operating conditions).The method further includes operating a first actual total number of cylinders of the internal combustion engine with poppet valves of the first actual total number of cylinders kept closed over a second engine cycle, and operating a second actual total number of cylinders with poppet valves of the second actual total number of cylinders opening and closing during the second internal combustion engine cycle in response to the vehicle being in sport mode and the electric machine not having torque capacity to provide the desired braking torque in the driveline.

[0084] The method further includes adjusting combustion in the internal combustion engine while the internal combustion engine is rotating. The method includes continuing to rotate the internal combustion engine via energy supplied to the internal combustion engine from the tires of the vehicle. The method includes stopping rotation of the internal combustion engine by decoupling the internal combustion engine from the vehicle tires and ceasing combustion in the internal combustion engine. The method further includes adjusting the supply of fuel to the internal combustion engine in response to the vehicle operating in sport mode and the electric machine having the torque capacity to provide the desired braking torque in the driveline.The method further includes operating a portion of engine cylinders with intake and exhaust valves opening and closing over an engine cycle in response to the electric machine having insufficient torque capacity to provide the desired braking torque in the driveline.

[0085] It should be noted that the example control and estimation routines included herein may be used with different internal combustion engine and / or vehicle system configurations. The control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and executed by the control system, including the controller in combination with the various sensors, actuators, and other internal combustion engine hardware. The specific routines described herein may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. Accordingly, various illustrated acts, operations, and / or functions may be performed in the illustrated order, in parallel, or in some cases, may be omitted.Likewise, the processing order is not necessarily required to achieve the features and advantages of the exemplary embodiments described herein, but rather is provided for ease of illustration and description. One or more of the illustrated acts, operations, and / or functions may be performed repeatedly depending on the particular strategy employed. Furthermore, at least a portion of the described acts, operations, and / or functions may graphically represent code to be programmed into non-transitory memory of the computer-readable storage medium in the control system.The control actions may also transform the operating state of one or more sensors or actuators in the physical world when the described actions are performed by executing the instructions in a system that includes the various engine hardware components in combination with one or more controllers.

[0086] This concludes the description. A reading of this description by a person skilled in the art will reveal many changes and modifications without deviating from the spirit and scope of the description. For example, this description can be applied to I3, I4, I5, V6, V8, V10, and V12 internal combustion engines operating on natural gas, gasoline, diesel, or alternative fuel configurations.

Claims

[1] Power transmission operating method comprising: Stopping fuel delivery to all engine cylinders and adjusting an actual total number of engine cylinders with operating poppet valves and an actual total number of engine cylinders with deactivated poppet valves in response to a braking torque in the powertrain during vehicle deceleration via a controller; and Adjusting the rotation of the internal combustion engine in response to a vehicle in which the internal combustion engine is not in a sport mode and an electric machine having torque capacity to provide braking torque in the powertrain. [2] The method of claim 1, wherein the poppet valves include inlet and exhaust valves and further comprising: Turning the internal combustion engine using energy supplied through vehicle wheels while fuel delivery is complete. [3] The method of claim 1, wherein the braking torque in the power transmission is a negative braking torque in the power transmission. [4] The method of claim 1, further comprising rotating the internal combustion engine in response to the braking torque in the powertrain. [5] The method of claim 4, further comprising starting the internal combustion engine to rotate the internal combustion engine in response to the braking torque in the powertrain and a lack of negative torque capacity of the electric machine to provide the braking torque in the powertrain. [6] Power transmission operating method comprising: Rotating an internal combustion engine and maintaining poppet valves of a cylinder of the internal combustion engine closed over a first internal combustion engine cycle in response to a vehicle operating in a sport mode and an electric machine having torque capacity to provide braking torque in the driveline; and Stopping the rotation of the internal combustion engine in response to the vehicle not operating in sport mode and the electric machine having torque capacity to provide braking torque in the powertrain. [7] The method of claim 6, further comprising operating a first actual total number of cylinders of the internal combustion engine with poppet valves of the first actual total number of cylinders kept closed over a second engine cycle, and operating a second actual total number of cylinders with poppet valves of the second actual total number of cylinders opening and closing during the second internal combustion engine cycle in response to the vehicle being in sport mode and the electric machine having no torque capacity to provide the braking torque in the driveline. [8] The method of claim 6, wherein the sport mode increases the performance of the vehicle. [9] The method of claim 6, further comprising adjusting the supply of fuel to the internal combustion engine in response to the vehicle operating in sport mode and the electric machine having the torque capacity to provide the braking torque in the driveline. [10] System comprising: an internal combustion engine; an electric machine coupled to the internal combustion engine; a transmission coupled to the electric machine; and a vehicle system controller having executable instructions stored in non-volatile memory to operate engine cylinders with opening and closing valves and without fuel in response to a torque capacity of the electric machine being less than a braking torque in the powertrain, and instructions stored in non-volatile memory to operate engine cylinders with closed valves over a plurality of engine cycles and without fuel in response to the torque capacity of the electric machine being greater than the braking torque for the powertrain; and executable instructions for adjusting the rotation of the internal combustion engine in response to a vehicle in which the internal combustion engine is not in a sport mode and an electric machine having torque capacity to provide braking torque in the powertrain. [11] The system of claim 10, further comprising a power transmission disconnect clutch between the internal combustion engine and the electric machine. [12] The system of claim 10, wherein the transmission is a dual clutch transmission. [13] The system of claim 10, further comprising additional instructions to determine whether a speed of a vehicle is outside a range of vehicle speeds. [14] The system of claim 10, further comprising an electric motor and a single-stage gearbox, wherein the electric machine and the electric motor are coupled to the single-stage gearbox.

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