Trailer Control Valve Pneumatic Pre-Pressurization for Synchronized Braking
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Solution Overview
Problem
Hydraulically braked towing vehicles coupled with pneumatically braked trailers experience delays in pneumatic brake pressure response due to low hydraulic braking pressures, leading to the trailer 'running up' and uneven braking distribution between the towing vehicle and trailer.
Innovation Solution
A method that controls and regulates pneumatic brake pressure in the trailer control valve by activating an actuator to generate hydraulic brake pressure, which then influences a pneumatic valve to pre-emptively generate pneumatic brake pressure before the hydraulic brake pressure reaches its response pressure, using driving operation parameters to adjust the pneumatic pressure application and duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional trailer control valves with inlet-exhaust valves are used, then the valve can provide required opening cross sections, but the response pressure is delayed (2-8 bar range) causing the trailer to run up
Solution Approach 1:
The patent applies preliminary action by using a pneumatic pre-pressurization circuit that activates before the hydraulic brake pressure reaches the response pressure threshold. A pneumatic valve receives control pressure from the hydraulic circuit and opens the inlet valve early, allowing pneumatic brake pressure to build up in advance. This preliminary pneumatic action ensures the trailer brake is ready to engage synchronously with the towing vehicle, eliminating the time delay caused by conventional hydraulic-only response mechanisms.
Solution Approach 2:
The patent introduces a pneumatic pre-pressurization circuit as an intermediary system between the hydraulic brake actuator and the trailer brake application. This intermediary pneumatic circuit receives control pressure from the hydraulic circuit through a pneumatic valve and uses it to trigger early inlet valve opening. The pneumatic intermediary translates the hydraulic control pressure into premature pneumatic brake pressure generation, bridging the response time gap without modifying the primary hydraulic braking system.
2Use of energy by moving object
If the hydraulic brake pressure is kept low in modern braking devices, then the braking system is more efficient, but the control volume for trailer control valve is severely limited
Solution Approach 1:
The patent combines pneumatic and hydraulic systems to overcome the volume limitation imposed by low hydraulic brake pressure. The pneumatic pre-pressurization circuit uses compressed air stored in a reservoir to generate the necessary control pressure for early inlet valve opening. This pneumatic supplement provides sufficient control volume and pressure buildup capability without requiring increased hydraulic system pressure, maintaining energy efficiency while enabling adequate trailer brake control.
3Area of stationary object
If the closing and opening stroke of the inlet-exhaust valve is increased, then the opening cross section is sufficient, but the stroke of the pneumatic weighing piston and hydraulic relay piston must also increase
Solution Approach 1:
The patent uses preliminary pneumatic action to achieve sufficient valve opening without requiring increased piston strokes. By pre-pressurizing the pneumatic circuit before the hydraulic pressure reaches response threshold, the system generates adequate pneumatic brake pressure early in the braking process. This allows the inlet valve to open sufficiently through pneumatic pressure buildup rather than requiring mechanically larger piston strokes, maintaining compact valve dimensions while ensuring adequate opening cross section for brake pressure flow.
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 ensures controlled and synchronized braking between the towing vehicle and trailer, preventing trailer overrun and improving braking efficiency by adjusting pneumatic pressure based on real-time driving conditions.
Implementation Method 1
a first piston surface (19) is subjected to the hydraulic brake pressure (pH) in a hydraulic pressure chamber (22)
Implementation Method 2
a second piston surface (44) can be acted upon pneumatically in a pneumatic pressure chamber (45)
Implementation Method 3
The force relationships on the weighing piston can be influenced via two separate control circuits
Data Source
AI summary
The method involves coupling a towing vehicle with a pneumatically limited hanger, and pneumatically-operating a hydraulic activated and complemented trailer control valve (4) by pneumatic pressure. Hydraulic braking pressure is generated by a brake actuator (8) for a service brake tube of the drawing vehicle. A piston area in the trailer control valve is loaded by the hydraulic braking pressure. The pneumatic pressure is forward controlled by the trailer control valve and is regulated dependent driving operating conditions during driving operation of the pneumatic pressure.