摘要:
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.
摘要:
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. The method preferably comprises a complementary series of software control functions that allow the vehicle to actively stop the engine.
摘要:
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.
摘要:
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. The plurality of first output torque command messages are used to obtain a torque reduction which is applied to a reference output torque to obtain a corresponding plurality of traction control output torque commands for the powertrain system during the wheel spin condition. A rate limit may also be applied to control the rate of change between successive ones of the traction control output torque commands in order to reduce the possibility of extension of the wheel spin condition, or recurrence of another wheel spin condition. Each traction control output torque command may be used to determine an associated traction control engine torque output command and traction control electric machine torque output command.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.