Abstract: A vehicle includes an engine, a transmission, a clutch, and a controller. The clutch is configured to couple the engine and transmission during engine starts. The controller is programmed to, in response to an actual engine start time being greater than an upper threshold time for an engine start event, alter an engine start torque apply schedule for the clutch such that the actual engine start time is less than the upper threshold time for a next engine start event. The controller may be further programmed to, in response to the actual engine start time being less than a lower threshold time for the engine start event, alter the engine start torque apply schedule for the clutch such that the actual engine start time is greater than the lower threshold time for the next engine start event.

Abstract: A system and method for controlling engine starting in a hybrid vehicle having an engine, a first electric machine selectively coupled to the engine by a first clutch, a second electric machine coupled to the engine, a step-ratio transmission selectively coupled to the electric machine by a second clutch include starting the engine using either the first electric machine or the second electric machine based on engine stop position. The first electric machine may be a low voltage starter motor or integrated starter-generator. The system and method may use the first electric machine when the engine stop position is within a specified range of positions relative to a piston top dead center position associated with higher cranking torques.

Abstract: A method and a system for improving operation of a hybrid vehicle are presented. In one example, torque converter impeller torque from beginning to end of transmission shifting is adjusted in response to variable driveline inertia. The approach may improve transmission shifting and reduce driveline torque disturbances.

Abstract: Methods and systems are provided for controlling an engine system with a variable cam timing device. In one example, the variable cam timing device is operated to adjust engine valve timing differently at engine stop based on whether the engine stop is in response to an operator request or in response to an automatic controller initiated engine stop without an operator request.

Abstract: Method and systems are provided for adjusting an engine torque in response to changes in a desired engine torque. In one example, a method may comprise responsive to increasing desired engine torques, monotonically decreasing an alternator torque to a first level from a second level when not injecting fuel to engine cylinders, and stepping up the alternator torque from the first level to the second level while initiating engine combustion, and then monotonically decreasing the alternator torque from the second level to the first level in response to the alternator torque reaching the first level. In this way, a method may comprise adjusting a load exerted on an engine by an alternator mechanically coupled to said engine during both cylinder combustion, and during non-fueling conditions.

Abstract: Systems and methods for operating a hybrid vehicle driveline that includes an engine and a motor are presented. In one example, the systems and methods include one or more control modes where engine and/or motor speed or torque is adjusted responsive to different control parameters during a vehicle launch from zero speed or a creep speed.

Abstract: A control system is provided to account for differences in engine response times and motor response times during an upshift in a transmission. A vehicle includes a driveline that has an engine, a traction motor, and a transmission selectively connected in series. A control area network (CAN) connects a plurality of controllers. At least one of the controllers is programmed to, during an upshift in the transmission, output signals over the CAN to reduce torque of the traction motor. The controller also reduces the engine torque based on signal delays in the CAN.

Abstract: Systems and methods for operating a driveline of a hybrid vehicle are disclosed. In one example, an engine may enter or stay in one of two cylinder modes in response to a request to a negative torque capacity of an electric machine being insufficient to provide a desired driveline braking torque. One cylinder mode operates cylinders with cylinder valves held closed and without fuel being injected to the cylinders while the other cylinder mode operates cylinders with valves that open and close without fuel being injected to the cylinders.

Abstract: Systems and methods for operating a driveline of a hybrid vehicle are disclosed. In one example, an engine may enter or stay in one of two cylinder deactivation modes or enter or stay in a combustion mode in response to a request to downshift a transmission while a vehicle in which the engine resides is coasting.

Abstract: Systems and methods for starting an engine of a hybrid vehicle are disclosed. The systems and methods disclosed may apply to series or parallel hybrid driveline configurations. In one example, engine cranking torque may be adjusted in response to a variety of operating conditions so that the engine may be started faster or slower.

Abstract: Methods and systems are provided for controlling clutch capacity in a hybrid electric vehicle. In one example, a method includes adjusting values of a transfer function of a clutch of a dual clutch transmission in response to an operating condition of an engine and/or operating condition of an integrated starter/generator coupled to the engine while a vehicle is propelled via an electric machine coupled to the dual clutch transmission, and maintaining a driver demand wheel torque at vehicle wheels via adjusting torque of the electric machine in response to the operating condition of the engine and/or operating condition of the integrated starter generator. In this way the method may apply pressure to one of the clutches where engine speed is independently controlled to maintain positive or negative slip, thus enabling adaptation of positive and negative clutch transfer functions, which may improve driveline operation and shift quality.

Abstract: Methods and systems are provided for operating a driveline of a hybrid vehicle that includes an internal combustion engine, an electric machine, and a transmission are described. In one example, the engine is started and coupled to the driveline via closing a clutch of a dual clutch transmission. Speed of the engine and clutch pressure are controlled to reduce driveline torque disturbances and provide a desired wheel torque.

Abstract: A vehicle includes an engine, a transmission, a clutch, and a controller. The clutch is configured to couple the engine and transmission during engine starts. The controller is programmed to alter an engine start torque apply schedule for the clutch such that the actual engine start time is less than the upper threshold time for a next engine start event. The controller may be further programmed to, in response to the actual engine start time being less than a lower threshold time for the engine start event, alter the engine start torque apply schedule for the clutch such the actual engine start time is greater than the lower threshold time for a next engine start event.

Abstract: Systems and methods for improving operation of a hybrid vehicle are presented. In one example, an engine is couple to a transmission in response to a transmission upshift to reduce transmission output shaft torque disturbances.

Abstract: A vehicle system includes a user interface device and an autonomous mode controller. The user interface device receives a user input representing a driving mode selection. The autonomous mode controller commands one or more vehicle subsystems to operate in accordance with characteristics associated with the driving mode selection. Examples of characteristics can include how aggressively the vehicle accelerates or decelerates, a minimum distance from the vehicle to a front vehicle, or how frequently the vehicle changes lanes, among others.

Abstract: A system and method for controlling a hybrid vehicle having an engine selectively coupled by an upstream clutch to an electric machine, which is selectively coupled by a downstream clutch to a step-ratio transmission, include at least one controller programmed to control the engine and the electric machine in response to entering a lash zone in anticipation of a wheel torque reversal to adjust a gain applied to an active motor damping torque controller to reduce driveline oscillations and backlash.

Abstract: A hybrid powertrain includes an engine having a crankshaft, and an electric motor having a rotor selectively coupled to the crankshaft via a disconnect clutch. The powertrain further includes a transmission having a torque converter that has an impeller fixed to the rotor. A controller is configured to, in response to the engine starting, generate a torque command for the motor that defines a magnitude that is based on a difference between a target impeller speed and a measured impeller speed.

Abstract: A vehicle includes an engine having a crankshaft, a transmission, an electric machine, and at least one controller. The transmission includes a torque converter having a turbine fixed to a turbine shaft that is driveably connected to driven wheels of the vehicle. The torque converter includes an impeller and a bypass clutch configured to selectively lock the impeller and the turbine relative to each other. The electric machine includes a rotor selectively coupled to the crankshaft via a disconnect clutch and fixed to the impeller. The at least one controller is configured to generate a first torque command for the electric machine that defines a magnitude equal to driver-demanded torque while the bypass clutch is locked. The controller is further configured to, in response to a reduction in fluid pressure supplied to the bypass clutch, generate a second torque command for the electric machine that defines a magnitude equal to driver-demanded torque plus impeller inertia torque.

Abstract: Method and systems are provided for adjusting an engine torque in response to changes in a desired engine torque. In one example, a method may comprise responsive to increasing desired engine torques, monotonically decreasing an alternator torque to a first level from a second level when not injecting fuel to engine cylinders, and stepping up the alternator torque from the first level to the second level while initiating engine combustion, and then monotonically decreasing the alternator torque from the second level to the first level in response to the alternator torque reaching the first level. In this way, a method may comprise adjusting a load exerted on an engine by an alternator mechanically coupled to said engine during both cylinder combustion, and during non-fueling conditions.

Abstract: A hybrid vehicle having an engine, an electric machine, and a step-ratio transmission includes a controller programmed to, in response to an accelerator lift-pedal event when operating in a towing mode, learn a vehicle speed, and apply a lift-pedal torque when vehicle speed exceeds the learned vehicle speed, and apply an adjusted lift-pedal torque based on a gear ratio after downshifting the transmission to maintain a constant output shaft torque otherwise.