Electropneumatic Trailer Valve Unit for Rapid Brake Pressure Output
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Solution Overview
Problem
Conventional electropneumatic trailer control systems require the trailer protection valve to switch before brake pressure can be output, leading to delays in pressure buildup and detection of trailer attachment, especially in North American variants where no check valve is provided, resulting in inefficiencies and potential air leakage.
Innovation Solution
An electropneumatic trailer control-valve unit with a pneumatically switched trailer protection valve that switches from a first to a second position when the trailer operating pressure exceeds a predetermined threshold, allowing for immediate brake pressure output and detection of trailer attachment, and optionally integrates a redundancy valve for enhanced air economy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the trailer protection valve is configured to switch before brake pressure can be output, then the system ensures safety by preventing brake pressure output when no trailer is attached, but this causes delays in pressure buildup and detection of trailer attachment
Solution Approach 1:
The brake-pressure pilot-control unit outputs control pressure in advance through the open trailer protection valve, and the brake-pressure main-valve unit prepares to output brake pressure immediately upon valve switching. This preliminary action eliminates the delay between valve switching and brake pressure output, while the valve's safety function remains intact as it only opens when trailer attachment is confirmed
2Loss of energy
If a check valve is provided in the red coupling head to prevent air leakage, then air economy is improved, but the device complexity increases and the system is less adaptable to different regional variants
Solution Approach 1:
The trailer protection valve serves multiple functions: it acts as a check valve to prevent air leakage when no trailer is attached, and simultaneously serves as a control element for enabling brake pressure output when a trailer is attached. This multi-functionality eliminates the need for a separate check valve, reducing component count while maintaining air economy across different regional variants
Solution Approach 2:
The invention merges the functions of the check valve and the trailer protection valve into a single integrated trailer protection valve. This combination reduces the number of components from two separate valves to one, simplifying the system structure while achieving both air leakage prevention and trailer attachment control functions
3Reliability
If the trailer protection valve is switched pneumatically requiring pressure buildup, then the valve switching is reliable, but the detection of trailer attachment is delayed
Solution Approach 1:
The brake-pressure pilot-control unit outputs control pressure in advance through the open trailer protection valve before the valve needs to switch. This preliminary pressure buildup eliminates the delay caused by pneumatic switching, as the pressure is already available immediately when the valve switches upon trailer attachment detection
Solution Approach 2:
The brake-pressure pilot-control unit acts as an intermediary that prepares the control pressure in advance, decoupling the valve switching reliability requirement from the detection speed requirement. The intermediary ensures the valve switches reliably while the system responds quickly to trailer attachment
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
Enables rapid output of brake pressures and improved detection of trailer attachment, reducing air leakage and enhancing system efficiency by allowing brake pressure output before the trailer protection valve switches, and providing redundancy pressure management for better air economy.
Implementation Method 1
a pneumatically switched trailer protection valve with a protection-valve control port which is connected to the trailer operating-pressure port for receiving the trailer operating pressure, wherein the trailer protection valve switches from a first switching position into a second switching position if the trailer operating pressure exceeds a predetermined first threshold value
Data Source
AI summary
An electropneumatic trailer control-valve unit for a vehicle, including a storage port for coupling a store of compressed air for a trailer, a brake-pressure port, a brake-pressure pilot-control unit configured to output at least one first control pressure, a brake-pressure main-valve unit configured to receive the at least one first control pressure and to output a brake pressure at a brake-pressure port, a trailer operating-pressure port configured to receive a trailer operating pressure, and a pneumatically switched trailer protection valve with a protection-valve control port which is connected to the trailer operating-pressure port for receiving the trailer operating pressure, wherein the trailer protection valve switches from a first switching position into a second switching position if the trailer operating pressure exceeds a predetermined first threshold value, and wherein the trailer operating pressure is a supply control pressure.