Electro-Pneumatic Valve for Adjustable Trailer Brake Gain
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Solution Overview
Problem
Conventional tractor-trailer braking systems face challenges in accommodating varying outlet pressures due to fixed gain hydraulic trailer brake valves, which are inadequate for both lower and higher pressure requirements, especially in agricultural machines with hydraulic service brakes that operate at much higher pressures than pneumatic systems.
Innovation Solution
An electro-pneumatic brake system is introduced, featuring an electro-pneumatic valve for breakaway control, which allows for adjustable gain across the hydraulic trailer brake valve, enabling simultaneous engagement of tractor and trailer braking systems with hydraulic and pneumatic components, and includes a leak detection mechanism to ensure safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed gain hydraulic trailer brake valve is used, then the system structure is simple, but the braking performance cannot be adjusted for different pressure requirements
Solution Approach 1:
The patent applies dynamics by replacing the fixed gain hydraulic trailer brake valve with an electro-hydraulic valve that enables adjustable gain. This allows the braking performance to be dynamically adjusted according to different pressure requirements, transforming a static system into a flexible, adaptive one that can accommodate varying operational conditions.
Solution Approach 2:
The patent substitutes the purely mechanical fixed gain valve with an electro-hydraulic valve that combines electrical control with hydraulic actuation. This replacement introduces electronic adjustability while maintaining hydraulic power transmission, enabling precise control of braking force without the limitations of mechanical fixed-gain designs.
2Power
If hydraulic service brakes operating at high pressure are used in agricultural machines, then braking power is sufficient, but the system is incompatible with standard pneumatic trailer brake systems
Solution Approach 1:
The patent introduces an electro-hydraulic valve as an intermediary device between the high-pressure hydraulic service brake system and the pneumatic trailer brake system. This intermediary converts and regulates the hydraulic pressure to appropriate levels for pneumatic brake operation, enabling compatibility between systems with different pressure requirements while preserving the high braking power of the hydraulic system.
Solution Approach 2:
The patent applies parameter changes by using the electro-hydraulic valve to transform the pressure parameter from the high-pressure hydraulic domain to the lower-pressure pneumatic domain. This parameter transformation allows the trailer brake system to operate at its designed pressure level while being driven by a high-pressure hydraulic source, achieving both power and compatibility.
3Reliability
If a mechanical breakaway valve is used in pneumatic brake systems, then breakaway detection is achieved, but the system cannot accommodate hydraulic service brakes with different operating pressures
Solution Approach 1:
The patent replaces the mechanical breakaway valve with an electro-pneumatic valve that provides breakaway detection capability. This electro-pneumatic valve can sense pressure changes indicative of breakaway conditions and respond by applying trailer brakes, while simultaneously being capable of operating with both pneumatic and hydraulic pressure sources, thus achieving both reliability and adaptability.
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 ensures reliable and adjustable braking performance across different pressure ranges, enhancing safety and compliance with changing federal and international guidelines by enabling proportional and fail-silent operation, particularly suitable for agricultural machines with hydraulic service brakes.
Implementation Method 1
an electro-pneumatic valve for breakaway control
Implementation Method 2
hydraulic service brakes that utilize a much greater operating pressure than a pneumatic or air brake system
Data Source
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AI summary
A method of detecting a leak in an air trailer brake circuit of a trailer includes providing a controller, a base valve, a first sensor, a second sensor, a leak control valve having a solenoid, a pneumatic fluid supply, a first brake output, and a second brake output. The method further includes supplying a first pressure to an inlet of the base valve and outputting a second pressure from an outlet of the base valve. The first pressure is detected with the first sensor and the second pressure is detected with the second sensor. The method also includes communicating the detected first pressure and the second pressure to the controller, and comparing a difference between first pressure and the second pressure to a threshold. A leak is detected in the air trailer brake circuit if the difference satisfies the threshold.