Abstract: A powertrain includes a diesel compression engine and an electric machine operatively coupled thereto and effective to rotate the engine during engine cranking. Cold engine cranking is accomplished in a staged manner including a first stage wherein the engine is cranked to a first speed below the resonant speed of the coupled engine and electric machine combination for a first duration and thereafter cranked to a second speed above the resonant speed for a second duration. Transition out of cranking at the first and second speeds is accomplished when relative combustion stability is demonstrated. Cranking at the first or second speed is aborted when excessive crank times or if low battery voltages are observed. A third stage is included wherein the engine is cranked to a third speed below the engine idle speed. Transition out of cranking at the third speed is accomplished when relative combustion stability is demonstrated, whereafter normal engine control takes over.

Abstract: A method for providing traction control in vehicle powertrain systems is particularly adapted for traction control in a powertrain system of a hybrid electric vehicle comprising an internal combustion engine, an electric machine and a transmission that is operatively coupled to the electric machine and the engine and adapted to provide a transmission torque output in response to a transmission torque input received as a torque output from either or both of the engine and the electric machine. The method is adapted to utilize conventional traction control and engine control hardware, software and communication standards to implement traction control. In one embodiment of the invention, a conventional traction controller is used to detect a wheel spin condition and provide a plurality of first output torque command messages in response thereto.

Abstract: A hybrid vehicle includes a powertrain having a retarded diesel engine, an electric machine and energy storage system. The engine and motor are operatively coupled through one or more planetary gearsets and selective coupling paths in accordance with application and release of various torque transfer devices to a drivetrain via an output. Regenerative and retarded engine braking are coordinated to provide priority to energy return to an energy storage system in accordance with predetermined power flow limits. Power flow in excess of the limits are handled by increased engine retard braking contributions via engine speed increases.

Abstract: A condition of impaired speed and torque control of a parallel electrically variable transmission due to factors beyond nominal modeling and estimation errors is diagnosed under low speed operation. The transmission includes at least one electric machine and a motor torque controller for regulating the transmission input speed and output torque. The motor torque controller includes an open-loop control path based on predetermined torques and accelerations and a closed loop control path based on input speed error. The presence of a larger than expected closed-loop correction magnitude, combined with low output speed and one or more other conditions is used to diagnose a condition of potential torque error, in which case the transmission control is altered to prevent unwanted operation.

Abstract: A hybrid vehicle includes a powertrain having a retarded diesel engine, an electric machine and energy storage system. The engine and motor are operatively coupled through one or more planetary gearsets and selective coupling paths in accordance with application and release of various torque transfer devices to a drivetrain via an output. Regenerative and retarded engine braking are coordinated to provide priority to energy return to an energy storage system in accordance with predetermined power flow limits.

Abstract: A hybrid powertrain has a transmission including a motor and a sensor for sensing rotation of the transmission output member. Motor speed signals are available from the motor controller. Speed signals representative of output speed are calculated from both the speed sensor and the motor speed in conjunction with known speed relationships between the motor and the output. A variety of in-range and dropped signal diagnostics is performed for the sensors and are used in the development of a set of software switches for selecting which of the speed sources is used as the output speed.