Pneumatic Trailer Control Valve with Dual-Outlet Backup
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Solution Overview
Problem
In towing vehicle-trailer combinations, the electrical and pneumatic brake circuits interfere, limiting the use of modern retarders and causing uneven braking, which results in increased wear and reduced braking efficiency, especially when the electrical signal fails, leading to inappropriate trailer braking.
Innovation Solution
The backup valve is connected to both control chambers, decoupling the electrical control circuit from the pneumatic control circuit, allowing independent electrical control of trailer brake pressure and ensuring the pneumatic circuit remains functional in case of electrical failures, thus enabling better utilization of retarders and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the backup valve is only upstream of the first control chamber, then the electrical control circuit can control trailer brake pressure, but the pneumatic signal incorrectly actuates the second control piston causing inappropriate trailer braking
Solution Approach 1:
The backup valve is segmented into two separate outlets: one outlet directs the pneumatic signal to the first control chamber, and a second outlet directs the pneumatic signal to the second control chamber. This segmentation allows independent control of each control piston, preventing the incorrect actuation that occurred when the pneumatic signal was only directed to the first control chamber.
2Loss of substance
If the electrical signal is used for brake blending with retarder, then wear is reduced, but the pneumatic circuit cannot be decoupled causing interference and limiting retarder utilization
Solution Approach 1:
The backup valve divides the pneumatic signal into two separate paths that can independently control the first and second control chambers. This allows the electrical control circuit to operate independently for brake blending with the retarder, while the pneumatic circuit remains available as a backup and can be decoupled when needed, enabling full utilization of the retarder without circuit interference.
Solution Approach 2:
The backup valve acts as an intermediary device that mediates between the electrical and pneumatic control circuits. It allows the pneumatic signal to be distributed to both control chambers independently, enabling the electrical circuit to control brake blending while the pneumatic circuit serves as a backup, thus resolving the interference between the two circuits and enabling full retarder utilization.
3Adaptability or versatility
If the backup valve controls both control chambers, then the circuits are decoupled for independent operation, but device complexity increases
Solution Approach 1:
The backup valve is designed with two separate outlets that segment the pneumatic signal distribution to the first and second control chambers. This segmentation enables independent operation of the electrical and pneumatic circuits while maintaining a relatively simple valve structure, as the segmentation is achieved through the valve's outlet configuration rather than through complex additional components.
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 solution allows for independent control of trailer brake pressure, reduces brake wear, and ensures compliance with legal braking requirements by decoupling the circuits, enabling better retarder usage and harmonized braking between the towing vehicle and trailer.
Implementation Method 1
the backup valve (7) seen from the foot brake module (14) the first control chamber (20) and at the same time the second control chamber (22) is arranged upstream
Implementation Method 2
the relay valve (8) modulates a brake pressure in the brake line (3) from a supply pressure
Data Source
AI summary
The pneumatic pilot-controlled trailer control module (1) has a pneumatic brake circuit with a back-up valve (7), which is controlled by an electronic control unit (13). The backup valve stays in connection with the two control chambers on the outlet side and is seen up-stream the foot brake module (14) of the two control chambers. An independent claim is also included for an electronic brake system with a pressure sensor.