Abstract:
A vehicle having an engine, a starter-generator, and a controller is disclosed. The controller is configured to respond to an engine start command, operate the engine to produce excess torque beyond a demand torque, and in response to engine speed achieving a threshold, operate the starter-generator to load the engine to consume the excess torque and drive the engine speed toward an electric machine speed, and engage a clutch to couple the engine and an electric machine.
Abstract:
A hybrid powertrain includes an engine having a crankshaft and a throttle body, and an electric machine having a rotor selectively coupled to the crankshaft via a disconnect clutch. A transmission of the powertrain includes a torque converter having an impeller fixed to the rotor, a turbine disposed on an input shaft of the transmission, and a bypass clutch configured to selectively transmit torque from the impeller to the turbine. A vehicle controller is programmed to, in response to the bypass clutch being open or slipping and the disconnect clutch being closed, command a throttle position of the throttle body based on an error between measured and estimated speeds of the impeller.
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 and configured to operate in torque control and in speed control. The powertrain further includes a transmission having a torque converter with an impeller fixed to the rotor, a turbine disposed on an input shaft of the transmission, and a bypass clutch configured to selectively transmit torque from the impeller to the turbine. A controller is configured to, in response to the motor switching from torque control to speed control, generate a torque command for the motor that defines a magnitude derived from an error between measured and estimated speeds of the impeller obtained during torque control to prevent a spike in motor speed when the motor switches from torque control to speed control.
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:
A vehicle includes an engine, electric machine, starter-generator, and a controller. The engine and electric machine are each configured to propel the vehicle. The starter-generator is coupled to the engine and is configured to adjust engine speed during an engine start-up event. The controller is programmed to, in response to engine speed increasing towards a target speed during an engine start-up event, generate a target drag torque with the starter-generator to reduce overshoot of the target engine speed.
Abstract:
A vehicle includes an engine, and a transmission including a torque converter having an impeller. The vehicle further includes an electric machine configured to provide drive torque to the impeller. The impeller is selectively coupled to the engine via a clutch. At least one vehicle controller is configured to, in response to the engine being OFF, the transmission being in DRIVE, a vehicle speed being zero and a brake pedal being released beyond a threshold position, command the electric machine to provide a torque to the impeller. The torque is a predetermined feedforward torque adjusted by a feedback torque that is based on a difference between measured and calculated speeds. The speeds may be the speeds of the electric machine.
Abstract:
A vehicle includes a powertrain having an electric machine configured to selectively apply regenerative braking torque to decelerate the vehicle. The vehicle also includes a controller programmed to control a rate of change of a regenerative braking torque limit during a transmission downshift that occurs during a regenerative braking event based on a change in speed of an output shaft of the powertrain caused by the transmission downshift.
Abstract:
A hybrid electric vehicle includes an engine and an electric machine, both capable of providing propulsion power. A clutch is configured to selectively couple the engine to the electric machine. At times, the vehicle may be subject to excessive loads, such as a large amount of weight in the vehicle or the vehicle towing another object. At least one controller is programmed to engage the clutch and start the engine in response to a load of the vehicle exceeding a predetermined threshold and a release of the brake pedal while the vehicle is stopped and in drive. This increases available engine torque prior to vehicle launch in anticipation of an upcoming acceleration demand.
Abstract:
A vehicle is provided with a powertrain including an electric motor, an internal combustion engine, and a turbocharger. The vehicle further includes a controller programmed to apply a variable filter to engine torque commands that are responsive to driver demand. The filter affects commands having a rate of increase greater than a predetermined threshold such that corresponding rates of increase in both engine torque and turbocharger speed are limited to respective rates less than the maximum available levels in order to reduce a surge in engine output emissions. The controller additionally issues commands for motor torque such that overall powertrain torque satisfies the driver demand.
Abstract:
A vehicle includes an engine having a crankshaft, a transmission having an input, and a torque converter mechanically coupled to the input. The vehicle further includes an electric machine mechanically coupled to the torque converter, a clutch configured to mechanically couple the electric machine and crankshaft, and one or more controllers. The one or more controllers are programmed to, in response to the transmission being in a drive or reverse gear and a speed of the vehicle being less than a predetermined value in an absence of driver demand, control the electric machine to achieve a target speed to cause the torque converter to output torque such that the speed of the vehicle approaches a generally constant speed less than or equal to the predetermined value when the vehicle is on a generally flat grade.