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: Systems and methods for improving operation of an engine are presented. In one example, a position of a throttle is adjusted along with other actuators to improve engine starting.

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.

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 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: A method and a system for improving operation of a hybrid vehicle are presented. In one example, an engine exhaust after treatment device is cooled at an opportunistic time. The approach may provide improved cooling for exhaust after treatment devices and it may also improve vehicle emissions.

Abstract: A hybrid vehicle includes an engine, an electric machine selectively coupled to the engine, a transmission having a torque converter impeller coupled to the electric machine and a torque converter clutch configured to selectively couple the impeller to a turbine, and a controller configured to control pressure of the torque converter clutch responsive to estimated clutch capacity, which is adjusted by the controller to equal impeller torque responsive to impeller speed exceeding turbine speed during clutch disengagement. A model of estimated torque converter clutch capacity may be stored in memory and adapted to actual clutch capacity by applying a gain or offset determined during opening of the clutch.

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 hybrid vehicle includes an engine, an electric machine selectively coupled to the engine, a transmission having a torque converter impeller coupled to the electric machine and a torque converter clutch configured to selectively couple the impeller to a turbine, and a controller configured to control pressure of the torque converter clutch responsive to estimated clutch capacity, which is adjusted by the controller to equal impeller torque responsive to impeller speed exceeding turbine speed during clutch disengagement. A model of estimated torque converter clutch capacity may be stored in memory and adapted to actual clutch capacity by applying a gain or offset determined during opening of the clutch.

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 operating an engine with deactivating and non-deactivating valves are presented. In one example, a position of one or more volumetric efficiency control devices is changed in response to a request to deactivate one or more engine cylinders while at the same time the engine central throttle is adjusted. Spark timing may also be adjusted if engine air flow deviates from a desired engine air flow.

Abstract: Systems and methods for transitioning a torque source between speed control and torque control modes during a vehicle creep mode are disclosed. In one example, torque of an electric machine is adjusted in response to a torque converter model. The torque converter model provides for a locked or unlocked torque converter clutch.

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: Systems and methods for operating a hybrid powertrain that includes an engine and a motor/generator are described. The systems and methods align in time an estimated motor torque and an actual motor torque to provide an estimated driveline torque. The alignment compensates for communications delays between different controllers over a controller area network.

Abstract: A vehicle includes at least one autonomous driving sensor configured to detect a traffic flow pattern relative to an intersection. An autonomous mode controller is configured to determine the state of the traffic control device. The autonomous mode controller may estimate when the state of the traffic control device is likely to change based on the traffic flow pattern.

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.

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.