Abstract: Systems and methods for operating an engine with a plurality of deactivating valves for deactivating engine cylinders are presented. In one example, a plurality of different cylinder operating modes may be available to operate the engine. Engine fuel consumption in each of the plurality of different cylinder operating modes is estimated and the engine may be operated in the cylinder mode that provides greatest fuel efficiency.

Abstract: Methods and systems are provided for monitoring torque delivery in a variable displacement engine using air flow metered via a throttle body model. During conditions when air flow estimation can be inaccurate, such as at wide open throttle, an induction ratio applied to the engine is constrained to 1.0, even if the operator torque demand is low. VDE degradation is inferred based on the commanded induction ratio relative to an actual induction ratio estimated based on the torque delivery.

Abstract: A system and method for modifying the engine pull-up (EPU) logic within a hybrid vehicle based on max motor torque that accounts for the drop or change in available motor torque due to the opening/slipping of a torque converter bypass clutch during engine starts is disclosed. An engine pull-up threshold is determined from max available motor torque at a virtual impeller speed, where the virtual impeller speed is the impeller speed that would result if the torque converter bypass clutch was open/slipping and transferring the same amount of torque.

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 speed control modes where torque output of a motor is adjusted responsive to different control parameters in the different control modes.

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, accelerator pedal position provides a basis for requesting vehicle acceleration and vehicle wheel torque is determined from the requested vehicle acceleration.

Abstract: A vehicle includes a step-ratio automatic transmission having clutches engageable to provide forward and reverse gears, an electric machine selectively coupled to the transmission, a main pump powered by the electric machine and supplying oil to actuate selected transmission clutches, a gear selector configured for selecting a transmission gear, and a controller configured to stop the electric machine when the gear selector selects park or neutral, to operate the electric machine in a speed control mode using a higher controller gain in response to the gear selector selecting forward or reverse while the electric machine is stopped until the electric machine and the main pump reach a first speed threshold to reduce engagement delay of at least one of the transmission clutches, and to operate the electric machine using a lower controller gain when the electric machine and the main pump exceed the first speed threshold.

Abstract: Methods and systems are provided for reducing engine torque using spark retard. In one example, a method may include calculating a spark timing for each firing event of a plurality of firing events individually in order to achieve a desired amount of reduced torque as an average torque over the plurality of firing events. An occurrence of random misfire may be reduced by rounding the spark timing for each firing event of the plurality of firing events to a stable region or a misfire region.

Abstract: Systems and methods for determining operation of a cylinder deactivating/reactivating device are disclosed. In one example, degradation of the cylinder deactivating/reactivating device is based on intake manifold oxygen concentration.

Abstract: Methods and systems are provided for monitoring torque delivery in a variable displacement engine using air flow metered via a throttle body model. During conditions when air flow estimation can be inaccurate, such as at wide open throttle, an induction ratio applied to the engine is constrained to 1.0, even if the operator torque demand is low. VDE degradation is inferred based on the commanded induction ratio relative to an actual induction ratio estimated based on the torque delivery.

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, values of an engine spark to engine torque relationship are adjusted to improve engine torque control. The engine is subsequently operated responsive to adjusted values of the engine spark to engine torque relationship.

Abstract: Systems and methods for operating an engine with a plurality of deactivating valves for deactivating engine cylinders are presented. In one example, a plurality of different cylinder operating modes may be available to operate the engine. Engine fuel consumption in each of the plurality of different cylinder operating modes is estimated and the engine may be operated in the cylinder mode that provides greatest fuel efficiency.

Abstract: Methods and systems are provided for rapidly charging a battery in a hybrid vehicle. In one example, a method includes charging a battery at a first rate via an engine transferring torque to a plurality of motor/generators while a vehicle speed is controlled based on a driver demand, and charging the battery at a second rate greater than the first rate via the plurality of motor/generators while the vehicle is autonomously controlled via a cruise control system. In this way, by charging the battery at the second rate while the vehicle speed is being controlled by the cruise control system, drivability issues related to engine torque production and/or motor/generator torque production may be minimized.

Abstract: Methods and systems are provided for operating a powertrain or driveline of a hybrid vehicle that includes two electric machines and a transmission are described. In one example, vehicle propulsion is maintained while transmission operating parameters are determined for improving transmission operation. In particular, a rear drive unit maintains vehicle speed and monitors torque delivered via an output of the transmission.

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: Systems and methods for improving operation of a hybrid vehicle are presented. In one example, driveline operation may be adjusted in response to operating the hybrid vehicle in a four wheel drivel low gear range. The approaches may improve vehicle drivability and reduce driveline degradation.

Abstract: Methods and systems are provided for operating a driveline of a hybrid vehicle that includes an internal combustion engine, a rear drive unit electric machine, an integrated starter/generator, and a transmission are described. In one example, inertia torque compensation is provided to counter inertia torque during a power-on upshift.

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, torque output from the engine and the electric machine is adjusted to provide controlled vehicle side slip during cornering by a vehicle.

Abstract: Methods and systems are provided for operating a driveline of a hybrid vehicle that may include an internal combustion engine, a rear drive unit electric machine, an integrated starter/generator, and a transmission are described. In one example, torque capacity of an on-coming clutch is adjusted during an inertia phase of a power-on upshift to improve shift smoothness.

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, where the transmission is downstream of the engine, and where the electric machine is downstream of the transmission. In one example, responsive to a driver-demanded wheel torque that exceeds a capacity of the electric machine, a vehicle acceleration plateau is avoided by transiently connecting a crankshaft of the engine to a low speed input shaft of the transmission while the engine is accelerating to a target speed.

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, where the transmission is downstream of the engine, and where the electric machine is downstream of the transmission. In one example, while the vehicle is being propelled solely via the electric machine, one or more gears of the transmission may be pre-engaged or selected, to prepare the driveline for an engine start event. In this way, driveline torque disturbance and delays in torque requests may be reduced or avoided upon a request for an engine start event.