Abstract: A method and system for executing a shift from a first fixed gear to a second fixed gear in a powertrain system comprising a two-mode, compound-split, electro-mechanical transmission operative to receive a speed input from an engine is described. It includes deactivating an off-going clutch, and generating a time-based profile for rotational speed of an oncoming clutch. The input speed is controlled based upon the rotational speed of the oncoming clutch and an output of the transmission. The oncoming clutch is actuated, preferably when the input speed is synchronized with a rotational speed of an output shaft of the transmission multiplied by a gear ratio of the second fixed gear, preferably after a predetermined elapsed period of time in the range of 500 milliseconds.

Abstract: An apparatus and method are provided to execute synchronous shifting in a powertrain system having multiple torque-generative devices each operable to independently supply motive torque to the transmission device. The exemplary transmission device comprises a two-mode, compound-split, hybrid electromechanical transmission. Operation includes operating in an initial fixed gear ratio, operating the transmission in a mode operation, and, operating the transmission in a final fixed gear ratio. The control system reduces reactive torque of a clutch activating the initial gear, and deactivates the first torque-transfer device when the reactive torque is less than a predetermined value. It determines that speed of an input shaft to the transmission is substantially synchronized with a rotational speed of the second torque-transfer device, and actuates the second torque-transfer device.

Abstract: A method and apparatus to control acceleration of a vehicle equipped with an electrically variable transmission and including a regenerative braking system, each are operably connected to a vehicle driveline. The method and apparatus include determining which one of a preselected shift selector position for the transmission is commanded, and determining operator demand for acceleration, using inputs from throttle pedal and brake pedal. Vehicle acceleration is measured, and magnitude of commanded torque transferred from the electrically variable transmission and the regenerative braking system to the vehicle driveline is controlled based upon the commanded preselected shift selector position, the operator demand for acceleration, and the measured vehicle acceleration.

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: Clutch engagement is preferably determined in accordance with monitored pressure conditions within a clutch control chamber. Clutch slip is monitored and information respecting clutch engagement inferred therefrom is stored for subsequent retrieval and use in a redundant slip based clutch engagement determination. Clutch slip is also monitored for information respecting clutch disengagement for use in a redundant slip based clutch disengagement determination.

Abstract: The derivative of a noise-containing input signal is determined by using an aliased derivative to periodically reset a filtered version of a normally determined derivative. The aliased derivative is calculated using a slower update or sampling rate than the normally determined derivative, and the filtered version of the normally determined derivative is reset to a reset value at each update of the aliased derivative. The reset value is based on a weighted sum of the aliased derivative and the filter output. The periodically reset filter output closely follows an idealized derivative of the input signal, substantially eliminating the phase delay introduced by conventional filtering.

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 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: An electrically variable transmission has a pair of clutches and a first mode when the first clutch is applied and the second clutch released, a second mode when the second clutch is applied and the first clutch released, and a fixed-ratio mode when both clutches are applied. Upshifts and downshifts out of fixed-ratio are accomplished in accordance with a control based upon shift confidence factors determined in accordance with proportional and derivative input speed error quantities. Shift cycling is avoided by applying a variety of conditional tests intended to inhibit return to fixed-ratio operation.

Abstract: A shift control for an electrically variable transmission shifts between modes through a neutral mode wherein the output is decoupled from the transmission. Normally, shifts between modes are accomplished synchronously through a duration of fixed-ratio operation. Extreme driving conditions may invoke shifts through neutral mode. Ratio violations characterized by one mode being active in a preferred input/output ratio range for another mode are handled by a shift through neutral. Similarly, rapid acceleration and deceleration conditions likely to result in undesirable engine speeds if synchronous shifting is employed are handled by a shift through neutral.

Abstract: A multi-mode hybrid transmission has speed control provided via an open loop model derived as a function of preselected transmission accelerations and controlled and uncontrolled transmission torques. Motor torques are selected as the controlled torques and other preselected transmission torques are selected as the uncontrolled torques. The control also employs a closed loop control effort responsive to at least one preselected transmission speed error.

Abstract: Synchronous shift control in a multi-mode, hybrid transmission utilizes motor torques to control clutch synchronizations and torque conditions thereacross for substantially torque disturbance free shifting from one mode to another.

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.

Abstract: An electrically variable transmission has a pair of clutches and a first mode when the first clutch is applied and the second clutch released, a second mode when the second clutch is applied and the first clutch released, and a fixed-ratio mode when both clutches are applied. Upshifts and downshifts out of fixed-ratio are accomplished in accordance with a control based upon shift confidence factors determined in accordance with proportional and derivative input speed error quantities. Additional authority limits are placed upon the shift confidence factors in accordance with output speed derivative quantities. Additional override downshift control is provided in accordance with additional input speed condition determinations.