Wheel Speed Sensor Thermal Measurement for Brake Maladjustment Detection

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Solution Overview

Problem

Conventional commercial vehicle brake systems often go undetected when out of adjustment, leading to increased stopping distances or overheating, which can impact braking performance and damage components, as existing monitoring approaches rely on rotor temperature estimation based on wheel speed and do not account for maladjustments effectively.

Innovation Solution

A system using wheel speed sensors to measure resistance values and determine temperatures, comparing them to predefined ranges and other sensors' temperatures to identify maladjustments, and generating adjustment signals to compensate for under- or over-adjusted brakes, thereby improving safety and preventing overheating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional rotor temperature estimation based on wheel speed is used, then braking performance monitoring is provided, but maladjusted brakes cannot be detected effectively

Engineering Contradiction:

Improvebrake monitoring reliabilityVSAvoidtemperature measurement precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical/indirect temperature estimation methods with direct thermal measurement using a thermistor sensor. Instead of estimating rotor temperature based on wheel speed and cooling models, the system directly measures the actual temperature at the wheel end where the brake component is located, providing precise detection of maladjusted brakes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a thermistor sensor as an intermediary measurement device between the brake component and the monitoring system. This sensor serves as a mediator that directly contacts or nears the brake assembly to capture accurate temperature data, which is then used to detect maladjustments that would otherwise remain undetected.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If manual brake inspection is performed, then maladjusted brakes can be detected, but vehicle downtime and operational complexity increase

Engineering Contradiction:

Improvebrake adjustment detectionVSAvoidoperational complexity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent enables the brake system to self-diagnose maladjustments through automatic temperature monitoring. The thermistor sensor continuously measures temperature, and the controller automatically compares readings against expected ranges to detect maladjusted brakes, eliminating the need for manual inspection by operators.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent implements a feedback mechanism where temperature data from the thermistor sensor is continuously fed back to the controller, which then determines whether the brake is properly adjusted. This closed-loop system provides real-time monitoring and automatic detection without requiring manual intervention.

Inventive Principle:

Principle #23Feedback

3Force

If over-adjusted brakes are allowed to operate, then brake pressure is maintained, but overheating and component damage occur

Engineering Contradiction:

Improvebrake pressureVSAvoidbrake temperature

Core Design Contradiction:

ForceVSTemperature

Solution Approach 1:

The patent applies preliminary anti-action by detecting temperature trends before critical overheating occurs. The controller monitors temperature readings and can identify maladjusted brakes that are trending toward overheating, allowing preventive action to be taken before actual damage occurs to brake components.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent uses a thermistor sensor, which is a relatively inexpensive and simple temperature sensing element. This cost-effective sensor provides continuous temperature monitoring to prevent expensive brake component damage from overheating, representing a low-cost protective measure against high-cost failures.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 solution allows for the detection and compensation of maladjusted brakes without manual inspection, enhancing vehicle safety, extending brake component life, and improving braking performance by adjusting brake pressure accordingly.

Implementation Method 1

determine a temperature of the individual wheel speed sensor as a function of the resistance value and ambient temperature

Methodology Applied

Scientific EffectResistive temperature detection: Electrical Resistance

Data Source

PatentUS10457263B2Brake adjustment detection using WSS based thermal measurement

Publication Date: 2019.10.29 BENDIX COMMERCIAL VEHICLE SYSTEMS LLC

AI summary

When detecting a maladjusted brake component on a commercial vehicle, wheel end temperature is determined as a function of resistance measured by a wheel speed sensor at a wheel end. The measured temperature is compared to low and high temperature thresholds defined by a thermal model, as well as to one or more other wheel speed sensor temperatures. If the measured temperature is below the low temperature threshold and substantially different than the one or more other wheel speed sensors, the brake is determined to be under-adjusted and brake force at the under-adjusted brake is increased. If the measured temperature is above the high temperature threshold and substantially different than the one or more other wheel speed sensors, then the brake is determined to be over-adjusted, and brake force is reduced or modulated at the over-adjusted brake to prevent overheating.