Motor Generator Torque Assist Control for Lock-Up Clutch Transitions
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Solution Overview
Problem
Existing vehicle drive technologies limit the use of motor generators to engine starting, not extending their functionality for torque assist during vehicle travel, which restricts drivability improvements.
Innovation Solution
A vehicle drive device and method that prohibits torque assist by a motor generator during lock-up transitions and permits it when specific conditions are met, except during lock-up transitions, allowing the motor generator to provide torque assist when the lock-up clutch is engaged or released, thereby enhancing drivability and fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If torque assist using motor generator is permitted during lock-up transition, then acceleration responsiveness is improved, but belt clamping force becomes insufficient causing transmission reliability issues
Solution Approach 1:
The control device prohibits torque assist during lock-up transition in advance before the transition occurs. This preliminary restriction prevents the belt clamping force from becoming insufficient during the critical transition period, ensuring transmission reliability while still allowing torque assist before and after the transition for acceleration responsiveness.
2Device complexity
If motor generator is used only for engine starting, then system simplicity is maintained, but drivability improvement is limited
Solution Approach 1:
The motor generator is extended from its traditional single function of engine starting to a multi-functional role that includes both engine starting and torque assist during vehicle travel. This universal application improves drivability and fuel efficiency while the control device manages the complexity by implementing conditional permission based on lock-up clutch state.
3Power
If torque assist is permitted during lock-up transition, then power output is increased, but belt slippage occurs reducing transmission efficiency
Solution Approach 1:
The control device proactively prohibits torque assist during lock-up transition before belt slippage can occur. This preliminary action prevents energy loss through slippage while still allowing torque assist to provide increased power output during stable operating conditions before and after the transition.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves acceleration responsiveness and fuel economy by allowing the motor generator to assist the engine torque during vehicle travel, preventing torque assist-related issues during lock-up transitions and optimizing energy recovery and consumption.
Implementation Method 1
a motor generator (MG) mechanically coupled to an output shaft (3) of the engine (2) via a belt (5)
Implementation Method 2
mechanically coupled to an output shaft of an engine via a belt
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A torque assist using a motor generator mechanically coupled to an output shaft of an engine via a belt is prohibited during a lock-up transition from a state where a lock-up clutch is released to a state where the lock-up clutch is engaged, and the torque assist using the motor generator is permitted when a condition for the execution of the torque assist is satisfied except during the lock-up transition.