Magnetorheological Clutch Coil Temperature Virtual Sensor

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Solution Overview

Problem

Traditional power steering systems experience inefficiencies due to continuous operation of hydraulic power steering pumps, leading to energy losses, and there is a need for monitoring and diagnosing the operating conditions of magnetorheological (MR) clutches connected to these pumps, particularly the coil temperature, to ensure durability and reliability.

Innovation Solution

A controller system that processes input signals from a vehicle's dynamic operating conditions to estimate the temperature of the MR clutch coil, triggering remedial actions or data storage algorithms if the temperature exceeds a threshold, without the need for a physical temperature sensor, using a look-up table calibrated with supply voltage, duty cycle, and current signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a physical temperature sensor is installed to monitor MR clutch coil temperature, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvecoil temperature measurementVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a virtual copy of the temperature sensor by using electrical parameters (voltage, current, duty cycle) to model and estimate the coil temperature through a look-up table, eliminating the need for a physical temperature sensor while maintaining diagnostic capability

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the physical temperature sensing mechanism with an electrical-based estimation system that uses existing electrical signals and a pre-calibrated look-up table to determine coil temperature, substituting mechanical/thermal sensing with electrical computation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a physical temperature sensor is installed to monitor MR clutch coil temperature, then reliability is improved, but manufacturing cost increases

Engineering Contradiction:

Improvesystem reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent makes the existing electrical signals serve multiple functions - they are used both for controlling the MR clutch operation and for estimating the coil temperature, eliminating the need for separate sensing hardware

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the power steering pump operates continuously to provide required flow and pressure, then power steering reliability is improved, but energy loss increases

Engineering Contradiction:

Improvepower steering reliabilityVSAvoidpump energy loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent makes the power steering pump operation dynamic by using the MR clutch to continuously adjust the pump speed based on actual steering demand, allowing the pump to operate at variable speeds rather than running continuously at fixed speed, thereby reducing energy losses during low-demand conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements periodic or demand-based activation of the power steering assistance through the MR clutch, which modulates the pump operation based on steering torque requirements, allowing the system to activate assistance only when needed rather than continuous operation

Inventive Principle:

Principle #19Periodic action

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

Enables efficient monitoring and diagnosis of MR clutch coil temperature, reducing system complexity and cost by providing a virtual sensor, allowing for timely remedial actions and data storage in case of over-temperature conditions, thus enhancing the reliability and efficiency of the power steering system.

Implementation Method 1

a MR clutch (125) having an excitation coil (230)

Methodology Applied

Scientific EffectElectromagnetism: Electromagnet

Implementation Method 2

magnetorheological (MR) clutch

Methodology Applied

Scientific EffectMagnetorheological effect: Magnetorheological Fluid

Data Source

PatentUS7302329B2Apparatus, system and method for magnetorheological clutch diagnostics

Publication Date: 2007.11.27 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

An apparatus and method for monitoring and diagnosing the coil temperature of a magnetorheological (MR) clutch connected to a power steering pump of a vehicle is disclosed. The apparatus includes a processing circuit, and a storage medium, readable by the processing circuit, for storing instructions for execution by the processing circuit for receiving a plurality of input signals representative of dynamic operating conditions relating to the vehicle, using the input signals to generate an output signal representative of a temperature of the coil of the MR clutch, determining from the output signal whether the temperature of the coil exceeds a threshold limit, and in response to the temperature of the coil exceeding a threshold limit, triggering at least one of a remedial action and a data storage algorithm.