Trailer Brake Fade Detection and Torque Gain Control
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Solution Overview
Problem
Friction-based speed reduction systems in vehicles and trailers experience fade due to heat, leading to reduced torque and ineffective speed control.
Innovation Solution
A control system adjusts the gain of negative torque commands to the vehicle and trailer systems to mitigate fade by reducing torque when detected, monitoring performance, and gradually increasing gain once fade is resolved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If friction-based speed reduction systems are used to generate negative torque, then speed control capability is improved, but torque output decreases when temperature increases due to heat
Solution Approach 1:
The control system continuously monitors the performance of friction-based speed reduction systems by comparing commanded negative torque with actual vehicle acceleration/deceleration. When fade is detected (actual torque < expected torque), the system reduces the gain of speed reduction commands to prevent overheating and maintain reliable speed control.
Solution Approach 2:
The system dynamically adjusts the gain parameter of speed reduction commands based on detected fade conditions. By changing the gain parameter in response to temperature-induced performance degradation, the system maintains effective speed control while preventing further overheating of the friction-based systems.
2Force
If gain of speed reduction commands is increased to improve speed control, then negative torque is increased, but heat generation increases causing fade
Solution Approach 1:
The control system periodically evaluates fade conditions by comparing actual vehicle response against expected response from commanded negative torque. This periodic assessment allows the system to adjust gain levels dynamically, increasing torque when cool and reducing torque when heating occurs, creating a cyclical adaptation pattern that prevents sustained overheating.
Solution Approach 2:
The system transitions from static gain settings to dynamic gain adjustment based on real-time fade detection. The gain parameter becomes a dynamic variable that adapts to changing thermal conditions of the friction-based speed reduction systems, allowing optimal torque delivery while preventing thermal runaway.
3Duration of action of stationary object
If friction-based speed reduction systems operate continuously, then speed control is maintained, but fade occurs due to accumulated heat
Solution Approach 1:
Continuous monitoring of torque delivery effectiveness provides feedback on the thermal state of friction-based systems. When fade is detected during continuous operation, the system reduces gain to allow cooling, preventing permanent damage and maintaining long-term reliability of the speed control function.
Solution Approach 2:
The system proactively reduces gain before complete thermal failure occurs by detecting early signs of fade through performance monitoring. This preventive approach cushions against catastrophic failure by allowing gradual cooling while maintaining adequate speed control, extending the safe continuous operation window.
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
The system effectively maintains consistent speed control by preventing torque reduction and ensuring the friction-based systems do not overheat, thereby enhancing vehicle and trailer performance.
Implementation Method 1
friction-based speed reduction systems of a trailer that is being towed by the vehicle
Implementation Method 2
negative torque (torque tending to reduce vehicle speed) generated by friction devices of the vehicle and/or trailer is increased or decreased when the gain is increased or decreased. Known friction-based devices to reduce vehicle speed may fade (i.e. provide reduced torque) when a temperature of the friction-based devices increases due to heat generated by the friction-base devices.
Data Source
AI summary
A vehicle includes a speed control system that is configured to increase and decrease vehicle speed when a command is received from a control system. The speed control system may include an engine that provides positive torque, and a friction-based system that is configured to provide negative torque to decrease vehicle speed. The control system may provide negative torque commands to activate a friction-based system of a trailer, and a trailer torque can be adjusted by changing a gain of negative torque commands to the trailer. The control system may utilize a baseline gain if trailer fade is not detected. The control system may decrease the gain of negative torque commands to the trailer if the negative torque of the trailer for an applied gain decreases with time.