Trailer Brake Ramp Control for Tow Vehicle Stability

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Solution Overview

Problem

Vehicles towing trailers experience amplified side slip during sudden maneuvers due to the momentum of the trailer, which can compromise vehicle stability and make existing vehicle stability control systems less effective.

Innovation Solution

A trailer brake control system that includes an electronic control unit communicating with a vehicle stability control system to generate a trailer brake output signal that ramps up to a target value when the vehicle stability control flag is set, maintaining this value until the flag is cleared, and then ramps down, thereby assisting in stabilizing the vehicle by reducing trailer momentum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the vehicle stability control system applies trailer brakes during sudden maneuvers, then the vehicle stability is improved, but the abrupt braking action can cause additional instability and discomfort

Engineering Contradiction:

Improvevehicle stabilityVSAvoidabrupt braking action causing instability

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The system applies a ramp-up period before full braking force is applied to the trailer brakes. When the vehicle stability control flag is set, the trailer brake output signal gradually increases to a target value over a predefined ramp period, cushioning the abrupt braking action and preventing additional vehicle instability during sudden maneuvers

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The system dynamically adjusts the trailer brake output signal based on the vehicle stability control flag state. The brake signal transitions from a ramp-up phase when the flag is set to a hold phase at target value, and then to a ramp-down phase when the flag is cleared, creating a dynamic braking response that adapts to changing vehicle stability conditions

Inventive Principle:

Principle #15Dynamics

2Speed

If the trailer brake output signal is applied immediately when stability control is needed, then the response time is improved, but the abrupt action can compromise vehicle stability

Engineering Contradiction:

Improvebrake response speedVSAvoidvehicle stability

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

The system implements a ramp-up period that begins immediately when the vehicle stability control flag is set, cushioning the brake application while maintaining rapid response. The trailer brake output signal gradually increases to the target value over the ramp period, providing both quick response and stability by avoiding abrupt full-force braking

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the trailer brakes are applied with high force to counteract trailer momentum, then the vehicle stability control effectiveness is improved, but the risk of wheel lockup and loss of control increases

Engineering Contradiction:

Improvestability control effectivenessVSAvoidwheel lockup risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system uses a ramp-up period to gradually apply brake force rather than immediate full-force braking. This cushioning approach allows the trailer brakes to counteract trailer momentum effectively while reducing the risk of wheel lockup and loss of control by avoiding sudden high-force application

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The system dynamically controls the trailer brake output signal with three distinct phases: ramp-up to target value when stability control is needed, hold at target value to maintain stability, and ramp-down when control is no longer needed. This dynamic control maintains reliability by applying sufficient brake force while preventing wheel lockup through controlled force progression

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11891037B2Systems, vehicles, and methods for vehicle stability control and trailer brake control collaboration

Publication Date: 2024.02.06 TOYOTA JIDOSHA KK

AI summary

A system for controlling a trailer brake output circuit includes an electronic control unit having one or more processors and one or more memory modules. The trailer brake output circuit is configured to output a trailer brake output signal. Machine readable instructions cause the electronic control unit to: receive a signal from a vehicle stability control system indicating that a vehicle stability control flag is set, generate the trailer brake output signal in response to the vehicle stability control flag being set such that the trailer brake output signal ramps up to a target value over a predefined period of time, maintain the trailer brake output signal at the target value while the vehicle stability control flag is set, and output the trailer brake output signal such that the trailer brake output signal ramps down from the target value when the vehicle stability control flag changes from set to not set.