Electropneumatic Trailer Parking Brake By-Wire Control When Uncoupled

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Solution Overview

Problem

Existing electropneumatic trailer parking brake systems lack ease of use and electrical or electronic control, particularly when the trailer is uncoupled, which hinders controllability in automated or semi-autonomous driving scenarios.

Innovation Solution

An electropneumatic trailer parking brake system with an electronic control unit that receives electrical signals to control a pilot valve arrangement, allowing for by-wire controllability, and includes a trailer control unit with electronic and pneumatic elements for independent operation, enabling manual and electronic actuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a trailer control valve in the towing vehicle is used to provide spring pressure for pneumatic control, then the parking brake system can be controlled from the towing vehicle, but the trailer lacks independent electrical or electronic control capability when uncoupled

Engineering Contradiction:
Improvecontrollability of trailer parking brakeVSAvoidindependent operation capability when uncoupled
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system separates control functions into two independent parts: a trailer control valve for pneumatic control from the towing vehicle, and a separate electronic control unit with pilot valve arrangement on the trailer for independent electrical control. This segmentation allows the trailer to operate independently when uncoupled while maintaining compatibility with towing vehicle control when coupled.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The parking brake system is designed to accept multiple types of control signals: pneumatic signals from the towing vehicle's trailer control valve and electrical signals from the trailer's own electronic control unit. The main valve unit can respond to either control method, providing universal control capability that works whether the trailer is coupled or uncoupled.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If pneumatic control only is used, then the system structure is simpler, but electrical or electronic control options for improved usability are not available

Engineering Contradiction:
Improveelectrical or electronic control optionVSAvoidsystem structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A pilot valve arrangement is introduced as an intermediary component that translates electrical control signals into pneumatic control signals. The electronic control unit generates electrical signals that actuate the pilot valve, which then controls the pneumatic flow to the main valve unit. This intermediary approach enables electrical control while maintaining compatibility with the existing pneumatic brake system architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system replaces purely pneumatic control with an electro-pneumatic control system. The electronic control unit with pilot valve arrangement substitutes for traditional mechanical or purely pneumatic control mechanisms, enabling by-wire controllability while maintaining the pneumatic actuation of the brake cylinders. This substitution improves usability and enables automated control options.

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

3Extent of automation

If the trailer parking brake system lacks electronic control capability, then the system is easier to operate manually, but controllability in automated or semi-autonomous driving functions is hindered

Engineering Contradiction:
Improveautomated or semi-autonomous control capabilityVSAvoidmanual operation simplicity
Core Design Contradiction:
Extent of automationVSEase of operation

Solution Approach 1:

The electronic control unit on the trailer provides self-service control capability, allowing the trailer to manage its own parking brake function independently of the towing vehicle's control systems. The electronic control unit receives operating signals and directly controls the pilot valve arrangement, enabling automated or semi-autonomous driving functions to control the trailer brakes without requiring manual intervention or complex integration with the towing vehicle's control systems.

Inventive Principle:
Principle #25Self-service

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

Provides improved controllability and usability of trailer parking brakes, allowing for electronic control even when uncoupled, enhancing safety and control during automated or semi-autonomous operations.

Implementation Method 1

a spring accumulator pressure at the parking brake port

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a main valve unit receiving the supply pressure, which is designed to control a spring accumulator pressure at the parking brake port depending on a control pressure applied to a control port

Methodology Applied
Scientific EffectPneumatics: Pressure Gradient

Data Source

PatentEP4466166B1Electropneumatic trailer parking brake system, trailer, trailer coupling
Publication Date: 2026.01.28 ZF CV SYST GLOBAL GMBH
  • EP4466166B1 patent drawingFigure 1
  • EP4466166B1 patent drawingFigure 2
  • EP4466166B1 patent drawingFigure 3

AI summary

The invention relates to an electro-pneumatic trailer parking brake system (102) for a trailer (201), comprising an electro-pneumatic trailer parking brake module (100), which is designed for releasing or engaging the trailer parking brake system (102) according to an operating signal (SB) and has a supply connection (20) for receiving a supply pressure (pV), a parking brake connection (21) for connecting a parking brake cylinder (24), a main valve unit (50) which is designed to control a spring force pressure (pF) at the parking brake connection (21) according to a control pressure (pS), and a pilot control valve assembly (70) for providing the control pressure (pS). According to the invention, an electronic control unit (300) is provided which is designed to receive the operating signal (SB) in the form of an electrical operating signal (SBE) for releasing or engaging the electro-pneumatic trailer parking brake system (102) and to provide an electrical switch signal (S, S1, S2) at the pilot control valve assembly (70) according to the electrical operating signal (SB), wherein the pilot control valve assembly (70) is designed to provide the control pressure (pS) according to the electrical switch signal (S, S1, S2).