Abstract: A control system for a modular hybrid electric vehicle operates an internal combustion engine at a torque level above the driver demanded torque improving the engine's efficiency. A traction motor driveably connected to the engine is operated at a torque level such that the combined torque satisfies the driver demand. The traction motor torque is limited to avoid inefficient combinations of speed and torque at which the motor is inefficient. During idle operation, the traction motor is operated at a torque determined from a battery state of charge and the engine is operated to maintain a predetermined speed. If the engine speed drops below a threshold, motor torque is adjusted to reduce the load on the engine to avoid stalling.

Abstract: A hybrid vehicle has an engine, an electric machine connected to the engine by an upstream clutch, a transmission gearbox connected to the electric machine by a downstream clutch, and a controller. The controller is configured to start the engine using one of a plurality of start sequences that control the electric machine, the upstream and downstream clutches. The engine start sequence is selected based on transmission gearbox input speed and a driver demand input. A method of controlling a hybrid vehicle is provided. An engine is selectively coupled to an electric machine by an upstream clutch with the electric machine selectively coupled to a transmission gearbox by a downstream clutch. The engine is started using a control sequence to control the electric machine, upstream clutch, and downstream clutch. The control sequence is determined by a vehicle state based on transmission gearbox input speed and a driver demand input.

Abstract: A system and method for controlling a vehicle having an electric traction motor coupled to a transmission by a clutch include modifying traction motor torque in response to the difference between rotational speed of a driveline component and the filtered rotational speed of the driveline component to reduce driveline oscillation when the clutch is locked. The traction motor torque may be modified in response to a vehicle event that may otherwise induce driveline oscillations, such as a transmission ratio change or regenerative braking, for example.

Abstract: A method for controlling a demand for engine power in a control for an engine in a hybrid electric vehicle with power-split characteristics. Following transitions from acceleration or deceleration operating modes to a steady-state operating mode, power demand excursions from road-load power are attenuated or avoided by filtering the power demand using a filter constant that changes within battery power constraints as a function of a normalized driver demand for power at traction wheels for the vehicle.