Hybrid PTO Speed Interlock Control System
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Solution Overview
Problem
In hybrid electric vehicles, the engagement and disengagement of the power take off (PTO) coupler can cause gear grinding due to speed differences between the transmission and the traction motor/generator, leading to mechanical issues if the transmission's internal drive gearing is not fully stopped.
Innovation Solution
A control system that uses sensors to monitor the speed of the electric traction motor/generator and limits PTO engagement to periods when the motor/generator is turning below a predefined maximum speed, preventing gear clashes by intelligently controlling the PTO actuator through a CAN-based architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the PTO coupler is engaged when the transmission gearing is not fully stopped, then the PTO can be activated quickly, but gear grinding and mechanical damage occur due to speed differences between components
Solution Approach 1:
The control system performs preliminary speed verification before allowing PTO engagement. The processor checks whether the transmission output shaft speed is below the threshold value before activating the PTO coupler, ensuring the transmission gearing is sufficiently stopped to prevent gear grinding and mechanical damage.
Solution Approach 2:
The system continuously monitors transmission output shaft speed through a speed sensor and provides feedback to the processor. This feedback mechanism enables real-time determination of whether engagement conditions are met, preventing harmful engagement while allowing quick activation when safe.
2Adaptability or versatility
If the PTO coupler includes an intermediary coupling and decoupling mechanism, then engagement flexibility is improved, but speed mismatch between transmission and PTO components causes gear clashes
Solution Approach 1:
Before the PTO coupler engages, the control system preliminarily verifies that the transmission output shaft speed is below the threshold. This preliminary speed check ensures that even with the flexible intermediary coupling mechanism, the actual engagement occurs only when speed mismatch is minimized, preventing gear clashes.
Solution Approach 2:
The control system acts as an intermediary between the transmission and PTO coupler, mediating the engagement process by monitoring speed conditions and controlling the timing of coupling activation. This intermediary control prevents direct harmful interaction between mismatched speed components.
Data Source
AI summary
A hybrid-electric vehicle powertrain including a first prime mover and an electric traction motor/generator provides for electric operation of a power take off. A sensor indicates electric fraction motor/generator speed. A control system provides for limiting engagement of the power take off to the electric traction motor/generator through a transmission to periods when the electric traction motor/generator is turning a less than a predefined maximum speed.