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:
A vehicle control system includes a controller that is programmed to, in response to an accelerator lift-pedal event, generate a drag torque, with at least one of an engine and electric machine, having a magnitude that is based on a deceleration fuel shut-off torque of the engine and a desired power output of the electric machine, and limit the drag torque to a threshold value that is based on the deceleration fuel shut-off torque.
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 vehicle includes a powertrain including an electric machine and a traction battery. The vehicle also includes at least one controller programmed to, during a transmission shift event, cause the electric machine to absorb torque. The torque absorption causes current generated by the electric machine to charge the battery according to a predetermined power transfer schedule defining a charge limit. The controller is further programmed to permit the current to exceed the charge limit for a predetermined duration of time in certain instances.
Abstract:
A vehicle includes an engine and an electric machine coupled to a transmission element. The electric machine is also selectively coupled with the engine by a clutch. The vehicle includes a belt integrated starter-generator (BISG) operatively coupled to the engine. An electronic controller includes one or more inputs adapted to receive a temperature measurement and a request to start the engine. The electronic controller is programmed to energize the BISG and the electric machine in response to receiving an engine start request and a temperature measurement being less than a threshold temperature measurement. The electronic controller is further programmed to close the disconnect clutch to apply torque from the electric machine to the engine in response to the electric machine achieving a threshold electric machine speed.
Abstract:
A vehicle includes a disconnect clutch selectively coupling an engine and an electric machine. The vehicle further includes a mechanical pump driven by the electric machine and operable to pressurize fluid for the clutch. The vehicle includes a controller programmed to, in response to the electric machine being inoperable, activate an auxiliary starter to start the engine, activate an electric pump operable to pressurize fluid to the clutch, and operate the engine to drive the mechanical pump.
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 system and method for controlling a vehicle powertrain including an engine and a motor operable to propel the vehicle includes reducing a torque of the motor at a first torque reduction rate from a torque level above a minimum motor torque in response to a deceleration request. A torque of the engine is reduced at a second torque reduction rate less than the first torque reduction rate in response to the deceleration request.
Abstract:
A powertrain controller for a vehicle may include input channels configured to receive start requests for an engine and operating condition data for an electric machine, and output channels configured to provide torque commands for the electric machine. The powertrain controller may further include control logic configured to, in response to receiving a start request for the electric machine while the operating condition data indicates that the electric machine is operating at a torque limit to drive the vehicle, generate torque commands that cause the electric machine to exceed the torque limit.