Method and arrangement in a hybrid vehicle for matching engine and generator torques at times of engagement and disengagement

Abstract

Method for calibrating and synchronizing sensed operating torques of an engine and a generator in a planetary gear based hybrid electric vehicle is disclosed. The method includes providing a sensor that detects the operational torque of an engine of a hybrid electric vehicle at the engine's interface with a planetary gear system of the hybrid electric vehicle. A sensor is provided that detects the operational torque of a generator of a hybrid electric vehicle at the motor's interface with the planetary gear system of the hybrid electric vehicle. The planetary gear system of the hybrid electric vehicle is operated in a split mode so that the generator is directly linked to the engine and a reading of the sensor that detects the operational torque of the generator may be used to compute the operating torque of the engine. Paired values of sensed operational torques of the engine and the generator at like times are recorded. Each pair of recorded values are arithmetically processed and a calibrating value is computed therebetween. The sensing and recording of paired values is repeated at the same sensed generator and engine speeds and torques thereby enabling the calculation of computed average calibrating values at each of the particular sensed generator speeds suitable for subsequent utilization in computing corresponding engine torques in the future. The engine and the generator are controlled utilizing the average calibrating value at future times of transition between power-split mode and parallel mode of the planetary gear system so that the engine is substantially synchronized with the generator at the time of direct linkage across the planetary gear arrangement thereby avoiding driver detectible irregularities in the performance of the power train of the hybrid electric vehicle.