Transmission Clutch Control for Vehicle Launch
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Solution Overview
Problem
Automatic engine starting and stopping can lead to undesirable transmission control, resulting in increased transmission degradation and poor vehicle launch performance, as existing systems lack effective methods to adjust clutch engagement based on real-time battery current and torque demands.
Innovation Solution
Adjusting the position of the transmission clutch in response to battery current during engine cranking, reducing clutch force when battery current exceeds a threshold to conserve battery life and increase torque transfer during engine restarts, and increasing clutch force when less than desired torque is transferred to improve vehicle launch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the clutch force is increased during engine cranking to improve vehicle launch, then torque transfer is improved, but battery current draw increases and battery life decreases
Solution Approach 1:
The clutch control system dynamically adjusts clutch engagement force based on real-time battery current measurements during engine cranking. The controller monitors battery current and modulates clutch actuator commands to optimize the balance between torque transfer requirements and battery power availability, transitioning from static to adaptive control
Solution Approach 2:
The system implements a feedback loop where battery current is continuously sensed during engine cranking and fed back to the clutch controller. This feedback enables the controller to adjust clutch engagement force in response to actual battery conditions, creating a closed-loop control system that adapts to varying power availability
2Duration of action of stationary object
If the clutch engagement is delayed during engine restart to conserve battery, then battery life is improved, but vehicle launch performance deteriorates
Solution Approach 1:
The system performs preliminary assessment of battery current conditions before finalizing clutch engagement timing and force. By evaluating battery state in advance during the cranking phase and pre-positioning the clutch for optimal engagement, the system prepares the powertrain for efficient torque transfer while preserving battery resources
Solution Approach 2:
The controller changes clutch engagement parameters (timing, force, duration) based on measured battery current characteristics. By adjusting these parameters dynamically rather than using fixed engagement profiles, the system optimizes the trade-off between launch performance and battery conservation for each specific operating condition
3Device complexity
If traditional transmission control is used during automatic engine stops and starts, then system simplicity is maintained, but transmission degradation increases
Solution Approach 1:
The transmission control system uses readily available sensor data (battery current, engine state) that already exists in the vehicle's control network. By leveraging existing sensor information and integrating clutch control with the automatic start-stop logic, the system achieves enhanced transmission protection without requiring separate dedicated sensors or complex additional hardware
Data Source
AI summary
Methods and systems for controlling a vehicle powertrain that may be automatically stopped and started are presented. In one example, a method adjusts a position of a transmission clutch in response to battery current during engine cranking. The method may reduce clutch wear and improve vehicle launch from a stop.