Vehicle Clutch Torque Handover During HEV-to-EV Shift Period
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Solution Overview
Problem
When switching from Hybrid Electric Vehicle (HEV) mode to Electric Vehicle (EV) mode, excessive torque change can cause a shock, leading to driver discomfort due to the disengagement of the engine from the wheels.
Innovation Solution
The vehicle control apparatus controls the clutch mechanism to be engaged for the entirety of a set shift period, decreasing engine torque and increasing motor generator power running torque during this transition, thereby reducing the shock experienced during mode switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the clutch mechanism is disengaged when switching from HEV mode to EV mode, then the engine is stopped and EV mode is achieved, but excessive torque change causes shock and driver discomfort
Solution Approach 1:
The control system maintains the clutch mechanism in an engaged state during a predetermined period before actually switching to EV mode. This preliminary engagement maintains the connection between the engine and transmission, preventing sudden torque changes and shock when the mode switching occurs, while still enabling the transition to EV operation.
2Object-affected harmful factors
If the clutch mechanism remains engaged during mode switching, then torque transmission is continuous, but the engine cannot be stopped for EV mode operation
Solution Approach 1:
The control system implements a timed preliminary engagement period where the clutch is maintained engaged before the actual mode switch. After this predetermined period elapses, the system then switches to EV mode with the clutch disengaged, allowing the engine to stop while having already prepared the system to avoid shock.
Solution Approach 2:
The control system dynamically adjusts the clutch mechanism's engagement state based on the switching phase. During the preliminary period, the clutch remains engaged for smooth torque transition; during EV mode operation after the period expires, the clutch transitions to disengaged state, enabling dynamic adaptation to different operational requirements.
Data Source
AI summary
A vehicle control apparatus includes a motor generator, an engine, a transmission mechanism, a clutch mechanism, and a control system configured to control the motor generator, the engine, the transmission mechanism and the clutch mechanism. The control system has a first traveling mode to engage the clutch mechanism and a second traveling mode to disengage the clutch mechanism. The control system is configured to set a shift period based on a transmission gear ratio of the transmission mechanism. The control system is configured to: control, upon switching from the first traveling mode to the second traveling mode, the clutch mechanism to be in a state where the clutch mechanism is engaged for an entirety of the shift period; and under the state where the clutch mechanism is engaged, decrease a torque of the engine and increase a power running torque of the motor generator.