Hybrid Vehicle Control Apparatus Torque Management
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Solution Overview
Problem
Hybrid vehicles face the issue of reverse engine operation due to variations in the operating response of the brake actuator when the locking mechanism transitions from a locked to an unlocked state, particularly during EV drive mode.
Innovation Solution
A control apparatus that reduces the absolute torque of the electric motor before changing the locking mechanism from a locked to an unlocked state, and optionally adjusts the torque direction or maintains the torque of a second electric motor to prevent reverse engine operation and ensure smooth transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the locking mechanism is changed from a locking state to an unlocking state during EV drive mode, then the engine can be operated to provide additional power, but a reverse rotary motion of the engine output shaft may occur due to variation in brake actuator response
Solution Approach 1:
The control device reduces the absolute value of electric motor torque before the locking mechanism transitions from locked to unlocked state. This preliminary action ensures that when the brake actuator releases the locking mechanism, the electric motor torque is already at a reduced level, preventing reverse rotation of the engine output shaft while still allowing the engine to be operated for additional power output.
2Reliability
If the electric motor torque is reduced before unlocking the output shaft, then reverse engine operation is prevented, but the vehicle power output may be temporarily reduced
Solution Approach 1:
The control device manages torque in a staged manner: first reducing electric motor torque before unlocking to prevent reverse operation, then subsequently increasing or maintaining power output through coordinated engine operation and second electric motor operation. This periodic control sequence ensures both reliability during transition and adequate power output during operation.
Data Source
AI summary
A control apparatus for a hybrid vehicle is provided with a differential mechanism having a first rotary element, a second rotary element serving as an input rotary member and connected to an engine, and a third rotary element serving as an output rotary member, an electric motor connected to said first rotary element, and a locking mechanism configured to fix an output shaft of said engine to a stationary member, the control apparatus comprising: an electric motor drive control portion configured to reduce an absolute value of a torque of said electric motor before said locking mechanism is changed from a locking state in which said output shaft is fixed to the stationary member while a drive force of said electric motor is transmitted to said third rotary element, to an unlocking state in which said output shaft is released from the stationary member.