Abstract: Systems and methods for operating a hybrid vehicle are presented. In one example, an integrated starter/generator (ISG) provides torque to restart an engine after the engine has been shut down and before engine speed is zero. An opening of a throttle is delayed to reduce driveline torque disturbances during engine restarting.

Abstract: Systems and methods for performing closed-in-bore diagnostics for a hybrid vehicle are presented. In one example, select operating conditions may be evaluated before closed-in-bore diagnostics may be initiated. In addition, charging of one or more batteries may be reduced to ensure that an engine throttle may operate with a small opening amount to evaluate the presence or absence of sludge in the engine throttle.

Abstract: Systems and methods for performing closed-in-bore diagnostics for a hybrid vehicle are presented. In one example, select operating conditions may be evaluated before closed-in-bore diagnostics may be initiated. In addition, charging of one or more batteries may be reduced to ensure that an engine throttle may operate with a small opening amount to evaluate the presence or absence of sludge in the engine throttle.

Abstract: Systems and methods for operating a hybrid vehicle are presented. In one example, an integrated starter/generator (ISG) provides torque to restart an engine after the engine has been shut down and before engine speed is zero. An opening of a throttle is delayed to reduce driveline torque disturbances during engine restarting.

Abstract: A hybrid vehicle includes an engine, an electric machine, a traction battery electrically connected to the electric machine, and a controller. The controller is programmed to, in response to the vehicle approaching a decline, overrepresent a state of charge (SOC) of the traction battery to cause a torque command to the engine to decrease and a torque command to the electric machine to increase such that discharge of the traction battery increases in advance of the decline.

Abstract: A method and system for operating a hybrid vehicle that includes an integrated starter/generator and a driveline disconnect clutch is described. In one example, the method determines whether or not to rotate an engine via an electric machine while propelling a vehicle via the electric machine according to vehicle efficiency.

Abstract: A hybrid vehicle includes an engine, an electric machine, a traction battery electrically connected to the electric machine, and a controller. The controller is programmed to, in response to the vehicle approaching a decline, overrepresent a state of charge (SOC) of the traction battery to cause a torque command to the engine to decrease and a torque command to the electric machine to increase such that discharge of the traction battery increases in advance of the decline.

Abstract: Methods and systems are provided for controlling engine operation in a hybrid electric vehicle equipped with stop/start capabilities under conditions where requested power or torque is in a hysteresis region between an engine pull up threshold and an engine pull down threshold. In one example, a method comprises obtaining an adjusted engine pull down threshold upon the requested power or torque remaining in the hysteresis region for more than a threshold duration, and commanding the engine deactivated in response to the adjusted engine pull down threshold being equivalent to the requested power or torque. In this way, a motor/generator may be used to meet the requested torque response rather than the engine under such conditions, which may improve fuel economy.

Abstract: A method and system for operating a hybrid vehicle that includes an integrated starter/generator and a driveline disconnect clutch is described. In one example, the method determines whether or not to rotate an engine via an electric machine while propelling a vehicle via the electric machine according to vehicle efficiency.

Abstract: A system and method for controlling a hybrid vehicle having an engine, a traction motor, and an automatic step-ratio transmission having a plurality of selectable discrete gear ratios include operating the electric machine to provide output torque associated with a first operating point selected based on driver demand torque and a current powertrain speed during transient operation, operating the electric machine to provide an output torque associated with a second operating point selected based on the driver demand torque and the current powertrain speed during steady state operation, and controlling the engine torque based on a difference between the driver demand torque and the electric machine torque.

Abstract: A system and method for controlling a hybrid vehicle having an engine and a traction motor include operating the engine at an operating point selected based on system efficiency, operating the electric machine to provide an electric machine torque responsive to a difference between a driver demand torque and the engine torque associated with the operating point, and limiting a rate of change of the electric machine torque in response to a rate of change of the driver demand torque. The electric machine torque rate limit may vary continuously responsive to the rate of change of driver demand torque and whether the driver demand torque is increasing or decreasing.

Abstract: Systems and methods for operating a vehicle that includes an engine that may be automatically stopped and started are described. In one example, a requested driver demand power may be filtered via a first order low pass filter in response to a powertrain speed. The filtered requested driver demand power may be a basis for automatically stopping and starting an engine.

Abstract: Methods and systems are provided for controlling engine operation in a hybrid electric vehicle equipped with stop/start capabilities under conditions where requested power or torque is in a hysteresis region between an engine pull up threshold and an engine pull down threshold. In one example, a method comprises obtaining an adjusted engine pull down threshold upon the requested power or torque remaining in the hysteresis region for more than a threshold duration, and commanding the engine deactivated in response to the adjusted engine pull down threshold being equivalent to the requested power or torque. In this way, a motor/generator may be used to meet the requested torque response rather than the engine under such conditions, which may improve fuel economy.

Abstract: Systems and methods for operating a vehicle that includes an engine that may be automatically stopped and started are described. In one example, a requested driver demand power may be filtered via a first order low pass filter in response to a powertrain speed. The filtered requested driver demand power may be a basis for automatically stopping and starting an engine.