Trailer Brake Line Pressure Sensing for Faster Combination Braking
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Solution Overview
Problem
Existing methods for controlling the brakes of a vehicle combination, particularly agricultural tractors with multiple trailers, face challenges in accurately determining the trailer status and line volume of the brake control line, leading to potential delays in brake actuation due to corrosion, dirt, or broken signal lines, and varying line lengths.
Innovation Solution
A method utilizing an electronically controlled brake control valve with magnetic switching valves, where a target pressure is produced in the brake control line through pulse-like openings, and the pressure variation and switching states are monitored to determine the trailer status and line volume by comparing characteristic values with reference values stored in a data memory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electric contacts of the trailer plug-socket are used to determine trailer status, then the trailer status can be detected, but the detection may fail due to corrosion, dirt, or broken signal lines
Solution Approach 1:
The patent uses pneumatic pressure as an intermediary medium to transmit trailer status information. Instead of relying on electric contacts that can corrode or break, the system uses the presence or absence of pneumatic pressure in the brake control line to indicate whether a trailer is coupled. This intermediary pneumatic signal is more reliable as it cannot be corroded or disconnected like electrical contacts.
Solution Approach 2:
The patent replaces the electrical detection system with a pneumatic-mechanical detection system. The trailer status is determined by measuring pneumatic pressure characteristics (pressure build-up rate, pressure level, pressure decay) in the brake control line, substituting the unreliable electrical contact-based detection with a more robust mechanical-pneumatic measurement approach.
2Adaptability or versatility
If the brake control line length is increased to accommodate multiple trailers, then more trailers can be coupled, but the line volume increases causing delayed brake actuation
Solution Approach 1:
The patent applies preliminary action by pre-determining the brake control line volume through pressure measurement before actual braking occurs. The control unit measures the pressure build-up characteristics to calculate the line volume, which indicates the number of coupled trailers. Based on this pre-determined volume information, the system can pre-adjust the brake control strategy to compensate for the expected delay, ensuring timely brake actuation regardless of line length.
Solution Approach 2:
The patent makes the brake control system dynamic by continuously monitoring pressure characteristics and adapting the control strategy based on the detected line volume. The system dynamically adjusts brake control parameters according to the actual trailer configuration detected through pressure measurement, optimizing brake response time for each specific configuration rather than using a fixed control approach.
3Speed
If a pressure pulse is delivered to enable rapid brake actuation, then brake response time is reduced, but the pressure level and duration must be precisely controlled based on line volume
Solution Approach 1:
The patent uses feedback by continuously monitoring the pressure build-up characteristics in the brake control line and using this information to determine the actual line volume. The control unit measures the pressure gradient or pressure build-up time, compares it with reference values, and adjusts the pressure pulse characteristics accordingly. This closed-loop feedback ensures that the pressure pulse is optimally controlled for each specific trailer configuration, achieving rapid brake response without excessive complexity.
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 accurate and rapid determination of trailer status and line volume, ensuring delay-free brake actuation by adjusting the brake control pressure based on real-time conditions, enhancing the control of vehicle combinations with trailers.
Implementation Method 1
an inlet valve and an outlet valve, which are in each case in the form of magnetic switching valves
Implementation Method 2
the brake control pressure present in the brake control line after a predetermined time interval since the inlet valve was closed is determined as a residual pressure by sensor means
Data Source
AI summary
A method is disclosed for controlling the brakes of a vehicle combination that includes a tractor vehicle and at least one trailer vehicle. A brake control valve in the tractor vehicle has magnetic switching valves that controlled by an electronic control unit, including an inlet valve and an outlet valve. To determine a current trailer status, it is determined whether the tractor vehicle is connected to a trailer vehicle and/or the line volume of the brake control line. A target pressure to be produced in the brake control line is specified and is produced by pulse-like opening of the inlet valve and/or the outlet valve. The brake control pressure in the brake control line is measured during the pressure build-up of pressure and a characteristic value for the trailer status and/or for the line volume of the brake control line is determined.