Towing Vehicle Brake Pressure Release for Jammed Parking Valves
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Solution Overview
Problem
Existing braking systems for towing vehicles face challenges in reducing hardware and software complexity while ensuring that a parking lock can be engaged in case of an unintentionally jammed valve.
Innovation Solution
The proposed solution involves a direct connection between the reservoir, the parking brake system, and the trailer control system, utilizing the trailer control valve to reduce pressure and avoid additional components. This includes cyclically engaging a brake valve to control the parking brake and empty the pressure medium source when the control valve or redundancy valve is jammed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a direct connection between the reservoir and trailer control system is used to reduce pressure, then the hardware complexity is reduced and additional components are avoided, but the system must ensure reliable parking brake engagement even when valves are jammed
Solution Approach 1:
The trailer control valve is made multi-functional by using it both for its original purpose of controlling trailer brakes and as a pressure reduction mechanism for the parking brake system. This eliminates the need for separate dedicated pressure reduction components, thereby reducing hardware complexity while maintaining reliability through the existing valve's controlled operation.
Solution Approach 2:
The brake valve is designed to cyclically engage and disengage, using its own operational cycles to reduce pressure in the supply line. This self-service mechanism allows the system to reduce pressure without requiring external intervention or additional dedicated pressure reduction components, maintaining reliability while minimizing hardware complexity.
2Reliability
If the brake valve is cyclically engaged to reduce pressure in the supply line, then the parking brake can be actuated by spring brake cylinders, but the system requires precise pressure control to reach the lower limit value
Solution Approach 1:
The brake valve is operated periodically through cyclic engagement and disengagement. This periodic action gradually reduces pressure in the supply line to the required lower limit value, enabling reliable parking brake actuation by spring brake cylinders while simplifying the control mechanism compared to continuous precise pressure regulation.
Solution Approach 2:
The system incorporates pressure sensors that provide feedback on the pressure level in the supply line. This feedback enables the electronic control unit to monitor and adjust the cyclic operation of the brake valve, ensuring that pressure reaches the precise lower limit value needed for reliable parking brake engagement while maintaining ease of operation through automated control.
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 reduces the pressure in the brake cylinders to a lower limit value, allowing the spring brake cylinders to actuate the parking brake system effectively, while minimizing complexity and ensuring safe operation even with a jammed valve.
Implementation Method 1
a drive motor of the towing vehicle can cause a filling of the pressure medium source, e.g., by driving a compressor that intakes, compresses, and supplies air to the pressure medium source
Implementation Method 2
the pressure in the brake cylinders reaches a lower limit value so that the spring brake cylinders used can actuate the parking brake system
Data Source
AI summary
A braking system for a towing vehicle is disclosed. The braking system includes a pressure medium source for supplying pressurized pressure medium, a parking brake module having a control valve and a redundancy valve, a trailer control valve system for a trailer brake of a trailer vehicle towed by the towing vehicle, and an electronic control unit. The electronic control unit is configured to control the trailer control valve system in such a way that pressure medium escapes via the trailer control valve system into a non-pressurized environment, whereby the pressure medium source is emptied, when the control valve or the redundancy valve persist in the open state due to a mechanical defect and otherwise should be in the closed state, and when an ignition of the towing vehicle and a compressor for filling the pressure medium source are switched off.