Hybrid Vehicle Engine Speed Control for Smooth Mode Transition
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Solution Overview
Problem
Hybrid electric vehicles experience sudden changes in engine rotation speed when transitioning from series travel mode to engine travel mode, leading to reduced marketability due to noise and vibration issues.
Innovation Solution
A control device that manages multiple travel modes by predicting and adjusting the engine rotation speed in stages to match the target speed when transitioning between modes, ensuring a smooth shift and preventing sudden changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the travel mode is shifted directly from the first travel mode to the second travel mode when a transition condition is satisfied, then the response speed of the vehicle control system is improved, but a sudden change in engine rotation speed occurs causing noise and vibration
Solution Approach 1:
The control device performs preliminary action by adjusting the engine rotation speed to a predicted rotation speed before the travel mode transition is completed. When a transition condition is satisfied, the control device calculates a predicted rotation speed corresponding to the vehicle speed at the timing of mode shift, and adjusts the engine rotation speed in advance to this predicted value, thereby preventing sudden speed changes and resulting noise and vibration during the transition to the second travel mode.
Solution Approach 2:
The control device applies dynamics by continuously adjusting the engine rotation speed based on real-time vehicle speed and predicted rotation speed. The engine rotation speed is dynamically modified toward the predicted rotation speed in response to the transition condition, allowing the system to adapt smoothly to the changing travel mode requirements without abrupt changes that cause noise and vibration.
2Object-generated harmful factors
If the engine rotation speed is adjusted in multiple stages to approach the predicted rotation speed, then the noise and vibration are reduced, but the time required for mode transition increases
Solution Approach 1:
The control device applies partial action by adjusting the engine rotation speed partially toward the predicted rotation speed during the transition period. The engine rotation speed is modified in a controlled manner to approach the predicted value without requiring complete stabilization before mode transition, thereby reducing noise and vibration while avoiding excessive transition time.
Data Source
AI summary
A control device of a vehicle configured to travel on a plurality of travel modes includes an internal combustion engine control unit and a travel mode control unit. When a difference between a rotation speed of an internal combustion at a time when a transition condition is satisfied and a predicted rotation speed is equal to or larger than a threshold value, the internal combustion engine control unit performs rotation speed control such that the rotation speed of the internal combustion engine approaches the predicted rotation speed, and the travel mode control unit shifts a travel mode to a second travel mode after the rotation speed control of the internal combustion engine control unit is completed. The rotation speed control is control in which the rotation speed is changed in a plurality of stages so as to approach the predicted rotation speed.