Trailer Brake Inlet Valve Control for Automatic Reversing

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Solution Overview

Problem

Conventional braking systems for trailer vehicles, especially those with hydraulic or pneumatic overrun brakes, face issues during reversing, where the trailer brakes undesirably when the towing vehicle moves forward, leading to vibrations and safety concerns, and manual intervention is required to prevent permanent deactivation of the brake system, which can result in increased braking distances and reduced traffic safety.

Innovation Solution

A braking system with an electrically actuated inlet valve integrated into the brake circuit, controlled by a unit that adjusts the valve between flow-through and blocking positions based on brake pressure and wheel speed signals to prevent brake medium flow during reversing, eliminating the need for manual intervention and ensuring the brake system remains operational.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the trailer is equipped with hydraulic or pneumatic overrun brakes, then the braking performance is improved, but the system becomes more complex and requires manual intervention during reversing

Engineering Contradiction:
Improvebraking performanceVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the purely mechanical automatic reversing system with an electronically controlled inlet valve system. The control unit receives signals from sensors (brake pressure sensor, wheel speed sensor) and automatically controls the inlet valve to block brake medium supply during reversing, eliminating the need for manual mechanical intervention while maintaining reliable braking performance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The braking system performs self-service by automatically detecting reversing conditions through sensors and controlling the inlet valve without requiring manual intervention. The system monitors brake pressure and wheel speed to determine when reversing is occurring and autonomously adjusts the brake medium flow accordingly.

Inventive Principle:
Principle #25Self-service

2Extent of automation

If manual intervention is required to return the actuating element to normal position after reversing, then the automatic reversing function works, but the ease of operation deteriorates and safety risks increase

Engineering Contradiction:
Improveautomatic reversing functionVSAvoidease of operation
Core Design Contradiction:
Extent of automationVSEase of operation

Solution Approach 1:

The system provides complete automation by using sensors to detect reversing conditions and automatically controlling the inlet valve. The control unit monitors brake pressure and wheel speed signals, and autonomously blocks or allows brake medium flow without requiring any manual intervention to return components to normal position, eliminating the forgetting risk entirely.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements feedback control by using brake pressure sensors and wheel speed sensors to continuously monitor the braking state and detect reversing conditions. The control unit processes these feedback signals and automatically adjusts the inlet valve position accordingly, creating a closed-loop control system that eliminates manual intervention requirements.

Inventive Principle:
Principle #23Feedback

3Reliability

If the inlet valve blocks brake medium flow during reversing, then unintended brake deactivation is prevented, but the device complexity increases

Engineering Contradiction:
Improvebrake system reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical blocking mechanisms with an electrically controlled inlet valve system. The valve is actuated by an electromagnetic coil controlled by a control unit, which simplifies the mechanical structure while improving reliability. The electronic control system can precisely manage brake medium flow based on sensor inputs without requiring complex mechanical linkages.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Device complexity

If the automatic reversing system is purely mechanical, then the device complexity is reduced, but the reliability deteriorates due to risk of accidental activation during deceleration

Engineering Contradiction:
Improvedevice complexityVSAvoidactivation reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system uses feedback from brake pressure sensors and wheel speed sensors to accurately determine when reversing is occurring. The control unit processes these signals and only blocks brake medium flow when both conditions confirm reversing, preventing accidental activation during normal deceleration while maintaining simple overall system architecture.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces the purely mechanical reversing detection mechanism with an electronically controlled system that uses sensor feedback. This substitution improves reliability by enabling more precise detection of reversing conditions through electronic sensors that can distinguish between normal deceleration and actual reversing, while keeping the physical valve mechanism relatively simple.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP4126607B1Brake system for a trailer vehicle, and trailer vehicle comprising such a brake system
Publication Date: 2024.06.05 VOLKSWAGEN AG
  • EP4126607B1 patent drawingFigure 1
  • EP4126607B1 patent drawingFigure 2
  • EP4126607B1 patent drawingFigure 3

AI summary

The invention relates to a brake system (7) for a trailer vehicle (3), comprising a brake circuit (17, 18); an actuation device (14), by means of which a brake pressure in the brake circuit (17, 18) can be adjusted; an inlet valve (23) which is arranged in the brake circuit (17, 18) between the actuation device (14) and a wheel brake element (16); a control unit (24) that can be used to adjust the inlet valve (23) into a blocking position in which a flow of a brake fluid (21) into the wheel brake element (16) is blocked; a brake pressure sensor (25), by means of which the control unit (24) can be provided with a brake pressure sensor signal; and a wheel rotational speed sensor system (30), by means of which the control unit (24) can be provided with a wheel rotational speed signal. According to the invention, the control unit (24) is designed to detect a reverse movement of the trailer vehicle (3) on the basis of the brake pressure sensor signal and the wheel rotational speed signal and on the basis thereof adjust the inlet valve (23) into the blocking position for the duration of the reverse movement. The invention additionally relates to a trailer vehicle (3) comprising a brake system (7).