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: This novel silent operating mode for a hybrid electric vehicle (HEV) reduces noise and emissions compared to traditional HEV operating modes. It is a complementary series of software control functions that allows the vehicle to operate with reduced noise and emissions where specifically needed, while phasing-in engine power where allowed. The method utilizes an energy storage system budget associated with a modal quantity of energy allocated for the mode, and is adapted to automatically adjust the operation of the vehicle to accommodate deviations from the budgeted energy amount. The mode also adjusts the vehicle operation in conjunction with changes in the parametric conditions of the ESS.

Abstract: Preferred operating points for a vehicle powertrain including an engine and a transmission are determined in accordance with a comprehensive operational mapping of input and output conditions and corresponding aggregate system losses corresponding to engine and transmission losses. In a hybrid transmission application, additional losses from motors and batteries are aggregated into the system losses and battery constraints are considered in determining preferred operating points.

Abstract: A driver-initiated low traction control method limits the drive torque of a motor vehicle during operation on low traction road surfaces. The low traction control mode is initiated by actuation of a switch or by moving a transmission range selector to a Low range while the vehicle is substantially stopped, and terminated by further actuation of the switch or by returning the range selector back to the Drive setting. The low traction control mode limits the engine torque as required to limit the drive wheel torque and its rate of change, so long as cruise control is inactive, the accelerator pedal setting is less than a reference level, and the transmission is operating in a gear other than its top gear. When the low traction control mode is terminated, the engine torque limits are progressively removed in a way that does not produce perceptible acceleration or deceleration of the vehicle.

Abstract: A method of operating a vehicle powertrain system comprising an electric motor and transmission where the electric motor is operably and selectively coupled to the transmission and adapted to provide an output torque contribution thereto, and the electric motor has a predetermined maximum motor output torque and a predetermined minimum motor output torque which are used to determine a range of permissible control points for at least one transmission control parameter.

Abstract: A method of operating a vehicle powertrain system comprising an electric motor and transmission where the electric motor is operably and selectively coupled to the transmission and adapted to provide an output torque contribution thereto, and the electric motor has a predetermined maximum motor output torque and a predetermined minimum motor output torque which are used to determine a range of permissible control points for at least one transmission control parameter.

Abstract: An preferred input torque for a hybrid powertrain is determined within a solution space of feasible input torques in accordance with a plurality of powertrain system constraints that results in a minimum overall powertrain system loss. Aggregate powertrain system losses are calculated at feasible input torques and a solution for the input torque corresponding to the minimum aggregate powertrain system loss is converged upon to determine the preferred input torque.

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 determining output torque limits of a powertrain including an electrically variable transmission relies upon a model of the electrically variable transmission. Transmission operating space is defined by electric machine torque constraints, engine torque constraints and battery power constraints. Output torque limits are determined at the limits of the transmission operating space.

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. Power flow in excess of the limits are handled by increased engine retard braking contributions via engine speed increases.

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 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: The normal control of an electrically-activated hydraulic valve armature is overridden to automatically and periodically open the armature for flushing out debris that has accumulated between the armature and a seat that the armature is designed to engage. The valve develops fluid pressure for maintaining engagement of a motor vehicle transmission clutch, and when excessive slippage of the clutch is detected, the armature is forced into engagement with the seat until the slippage is reduced or a predetermined period of time has elapsed, after which the armature is temporarily positioned away from the seat to provide full flow of hydraulic fluid across the seat to flush out debris that prevents the armature from engaging the seat. During Neutral operation of the transmission, the armature is continuously positioned away from the seat, and during low torque conditions the armature is temporarily positioned away from the seat.

Abstract: A method of operating a vehicle powertrain system comprising an electric motor and transmission where the electric motor is operably and selectively coupled to the transmission and adapted to provide an output torque contribution thereto, and the electric motor has a predetermined maximum motor output torque and a predetermined minimum motor output torque which are used to determine a range of permissible control points for at least one transmission control parameter.

Abstract: A method for determining output torque limits of a powertrain including an electrically variable transmission relies upon a model of the electrically variable transmission. Transmission operating space is defined by combined electric machine torque constraints and engine torque constraints. Output torque limits are determined at the limits of the transmission operating space.

Abstract: A method for providing an active engine stop of the engine of a hybrid electric vehicle. The method utilizes the electric machine to oppose the and rapidly stop the rotation of the engine at a controlled rate. The method includes the calculation of an input speed reduction trajectory using the engine speed when the active engine stop request is made and a predetermined speed reduction interval. The predetermined speed reduction interval is preferably less than a time from the active stop request to the shutoff command to the electric machine. The method provides rapid deceleration of the engine, particularly through the powertrain resonance speed, thereby reducing the amount of vibration energy dissipated through the powertrain and vehicle chassis. The method also removes the electric machine torques from the engine prior to achieving zero engine speed in order to avoid imparting a negative engine speed or counter-rotation of the engine.

Abstract: A method of testing an electric motor that is adapted to provide a desired electric motor output torque to a vehicle powertrain system comprising an engine and the electric motor which are operatively and selectively coupled to a transmission. The method includes the steps of determining an initial motor speed of the electric motor, determining a motor torque command as a function of the initial motor speed, applying the motor torque command to the electric motor to produce an output torque from the electric motor, measuring a resultant motor speed of the electric motor and establishing a motor status as a function of the resultant motor speed. The method may be implemented as a computer control and diagnostic algorithm.

Abstract: A vehicular powertrain includes operatively coupled engine, electrically variable transmission and driveline. During normal operation when all motors are operating as expected, the engine is operated in a torque control mode in accordance with a torque command provided by a system controller to an engine controller and engine speed is controlled by the motors. During operation when all motors are not operating as expected, the engine is operated in a speed control mode in accordance with a speed command provided by the system controller to the engine controller and engine load torque is controlled by the operative motors.

Abstract: A method for determining output torque limits of a powertrain including an electrically variable transmission relies upon a model of the electrically variable transmission. Transmission operating space is defined by electric machine torque constraints, engine torque constraints and battery power constraints. Output torque limits are determined at the limits of the transmission operating space.