Hybrid EV Ignition Torque Control for Vibration Reduction
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Solution Overview
Problem
Hybrid electric vehicles experience vibration during engine ignition due to mechanical loss components like pumping torque, which also require higher average torque from the ignition motor, affecting startability.
Innovation Solution
A method for controlling a hybrid electric vehicle that predicts torque changes during engine ignition by considering motoring pressure, inertial, and combustion pressure torques, and applies correction torque to minimize vibration by inverting predicted torque components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ignition motor applies larger average torque to overcome pumping torque during engine ignition, then the engine can be started, but vibration increases and startability deteriorates
Solution Approach 1:
The controller predicts the torque change caused by pumping torque before it occurs during engine ignition, and applies correction torque in advance to counteract the harmful vibration. This preliminary anti-action allows the ignition motor to maintain smaller average torque while still preventing vibration, resolving the contradiction between reliable starting and vibration reduction.
Solution Approach 2:
The system uses feedback control by continuously monitoring engine rotation speed and calculating the torque change required to maintain stable rotation. The controller adjusts the correction torque based on the predicted pumping torque effects, enabling precise control that reduces vibration without requiring excessive average torque from the ignition motor.
2Reliability
If the ignition motor applies larger average torque to ensure reliable engine start, then engine ignition succeeds, but the required torque increases and startability performance deteriorates
Solution Approach 1:
By predicting the torque change before pumping torque acts on the engine, the system applies correction torque proactively. This allows the ignition motor to use smaller average torque while still ensuring reliable ignition, directly resolving the contradiction between ignition success rate and torque requirement.
Solution Approach 2:
The controller performs preliminary calculation of the torque change required to compensate for pumping torque effects before the actual ignition process. This preliminary action enables the ignition motor to be sized smaller while maintaining reliable start capability, improving overall system efficiency.
Data Source
AI summary
The present disclosure relates to a hybrid electric vehicle and a method for ignition control for the same. The hybrid electric vehicle includes a power train including an engine, a motor, and a shaft to which the engine and the motor are connected together. The vehicle also includes a controller configured to predict, during the ignition, a torque change in the shaft by determining whether to apply a vibrational contribution due to combustion pressure torque according to whether initial explosion has occurred during ignition of the engine, and control torque of the motor during the ignition based on the predicted torque change, which can reduce vibration in an ignition process of the hybrid electric vehicle and enhance startability by predicting vibration and applying antiphase torque during ignition.