Hybrid Vehicle Motor Generator Direct Coupling
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Solution Overview
Problem
Existing hybrid vehicle systems face limitations in torque capacity and efficiency, particularly when using a single motor for power running and regenerative drives, due to the configuration of the motor and variator, which can lead to increased costs and mass with dual-motor systems or inefficiencies in torque transmission.
Innovation Solution
A hybrid vehicle system is designed with a single motor generator and an automatic transmission that includes a forward-reverse travel switching mechanism, allowing the motor to directly couple with the drive wheels without the variator, enabling efficient power running and regenerative drives by decoupling the variator during specific operational states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the motor is disposed upstream of the variator, then the motor can contribute to torque input to the variator, but the torque capacity of the variator becomes a limitation and it is difficult to increase torque capacity outputted to drive wheels
Solution Approach 1:
The power transmission path is segmented into multiple independent paths: one path through the variator for continuous variable transmission, and another direct path from the motor to the drive wheels bypassing the variator. This segmentation allows the motor to directly output torque to the drive wheels without being limited by the variator's torque capacity, while the variator handles torque conversion for engine power.
Solution Approach 2:
A clutch mechanism is introduced as an intermediary device to selectively connect or disconnect the motor from the drive wheels. This clutch allows the motor to be coupled to the drive wheels when additional torque is needed, and disconnected when the variator alone suffices, thereby overcoming the variator's torque capacity limitation without requiring a completely different transmission architecture.
2Power
If a dual-motor system is used to increase torque capacity, then more power can be outputted to drive wheels, but costs and mass increase
Solution Approach 1:
The single motor is designed to perform multiple functions: it can directly drive the drive wheels for power running, act as a generator for regenerative braking by being directly coupled to the drive wheels, and be selectively engaged or disengaged based on driving conditions. This multi-functionality eliminates the need for a second motor while maintaining the capability to provide high torque output when needed.
3Loss of energy
If the motor is disposed downstream of the variator, then the motor can be coupled to drive wheels, but in electric travel or regenerative operation the motor and drive wheels are coupled via the variator which degrades efficiency
Solution Approach 1:
The motor is extracted from the traditional downstream position behind the variator and placed in a direct coupling position with the drive wheels. This extraction allows the motor to bypass the variator entirely during electric travel and regenerative operation, eliminating the transmission losses associated with variator operation while maintaining the ability to use the variator when engine power is required.
Data Source
AI summary
A hybrid vehicle system includes an engine, a transmission mechanism, first and second clutch mechanisms, a motor generator, and a forward-reverse travel switching mechanism. The engine outputs torque. The transmission mechanism converts the torque at a predetermined transmission gear ratio. The first clutch mechanism allows and disallows power transmission between the transmission mechanism and a drive wheel. The motor generator is coupled to a power transmission path between the first clutch mechanism and the drive wheel. The second clutch mechanism allows and disallows power transmission between the motor generator and the drive wheel. The forward-reverse travel switching mechanism is coupled to a power transmission path between the engine and the transmission mechanism. The forward-reverse travel switching mechanism is coupled to a countershaft. The forward-reverse travel switching mechanism switches among a forward-travel direct coupling state, a reverse-travel direct coupling state, and a neutral state.