Vehicle PTO Clutch Control Under Slip and Thermal Limits
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Solution Overview
Problem
Power take off (PTO) units in vehicles often fail to supply rated torque due to temperature thresholds and efficiency losses, leading to potential degradation and reduced functionality.
Innovation Solution
Maintaining or increasing the closing force of the PTO clutch and reducing the torque output of the electric machine when clutch slip exceeds a threshold, thereby reducing temperature and preventing degradation while continuing to supply mechanical power to external devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the PTO operates at high torque output, then power delivery to external devices is improved, but temperature increases causing degradation
Solution Approach 1:
The PTO system dynamically adjusts torque output based on real-time temperature monitoring. When temperature exceeds thresholds, the system automatically reduces torque delivery to prevent degradation, creating a dynamic operating regime that adapts to thermal conditions rather than maintaining fixed high-power output
Solution Approach 2:
The system changes operational parameters (torque output, rotational speed) in response to temperature changes. By monitoring temperature and adjusting torque delivery accordingly, the system transitions between different operating states to balance power delivery with thermal management
2Reliability
If the PTO clutch slip is reduced to prevent degradation, then reliability is improved, but power delivery capability deteriorates
Solution Approach 1:
The system applies partial torque reduction rather than complete shutdown when clutch slip is detected. By reducing torque output to a level that prevents degradation while maintaining some power delivery, the system achieves partial action that balances reliability with continued operational capability
Solution Approach 2:
The PTO system continuously monitors clutch slip conditions and uses this feedback to adjust torque output. When slip exceeds thresholds, the system responds by reducing torque delivery, creating a closed-loop control mechanism that maintains reliability while preserving power delivery when conditions permit
3Duration of action of stationary object
If the PTO is stopped to prevent degradation, then longevity is improved, but operational continuity deteriorates
Solution Approach 1:
The system takes preliminary action by reducing torque output before critical degradation occurs. By proactively adjusting torque when temperature or slip approaches problematic thresholds, the system prevents the need for complete shutdowns while still protecting against degradation
Solution Approach 2:
The PTO system implements periodic monitoring and adjustment of operating parameters. Through continuous temperature and slip monitoring with periodic torque adjustments, the system maintains operational continuity while periodically preventing degradation conditions
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 reduces the likelihood of PTO degradation, allows external devices to continue operating, and enables operators to adjust loads for smoother power delivery by identifying high-torque rotational angles.
Implementation Method 1
slip of the clutch...causing the power take off to operate outside of a desired operating range, torque output of an electric machine may be reduced so that power take off clutch slip may be reduced. In addition, a temperature of the power take off device may be reduced after torque output of the electric machine is reduced since the power take off clutch may slip less
Data Source
AI summary
Systems and methods for operating a power take off of a vehicle are described. In one example, operation of the power take off may be maintained even when slip of a power take off clutch is detected. In particular, the power take off may be operated at a lower output until the power take off may handle larger loads.