Vehicle Sensor Shape Memory Alloy Actuator Debris Detection

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Solution Overview

Problem

Existing sensor systems for vehicles fail to effectively detect and clear debris such as ice or mud from surfaces, which can impede their functionality and line of sight, especially in inclement conditions.

Innovation Solution

A sensor system utilizing a shape memory alloy actuator and plunger mechanism that differentiates between debris-covered and debris-free states through temperature-dependent transitions, allowing for detection and potential cleaning of debris from vehicle surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a shape memory alloy actuator is used to detect and clear debris, then the sensor system can automatically clear debris from surfaces, but the device complexity increases due to the added actuator and plunger mechanism

Engineering Contradiction:

Improveautomatic debris clearingVSAvoidactuator and plunger mechanism

Core Design Contradiction:

Extent of automationVSDevice complexity

Solution Approach 1:

The shape memory alloy actuator is activated by thermal energy from the debris itself (ice or mud), allowing the system to clear its own surface without external intervention. The actuator autonomously transitions between states based on temperature changes, enabling self-powered debris removal that reduces the need for complex external actuation mechanisms.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The shape memory alloy changes its physical state (martensite to austenite) in response to temperature changes, which alters its mechanical properties and enables the actuator to generate force for plunger movement. This parameter-based actuation simplifies the control system while achieving automated debris clearing.

Inventive Principle:

Principle #35Parameter changes

2Strength

If the plunger is constrained during debris-covered conditions, then the actuator experiences higher stress that may damage the system, but the measurement precision of debris detection is reduced

Engineering Contradiction:

Improveactuator stress protectionVSAvoiddebris detection accuracy

Core Design Contradiction:

StrengthVSMeasurement precision

Solution Approach 1:

The resilient member is pre-positioned to engage with the plunger before debris accumulation occurs. When debris covers the sensor surface, the resilient member absorbs the stress that would otherwise be transmitted to the actuator, protecting it from damage while still allowing the system to detect the debris condition through the plunger's constrained movement.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The resilient member acts as an intermediary between the plunger and the actuator. It transmits the plunger's movement under normal conditions for accurate debris detection, but absorbs excessive stress when debris is present, thereby protecting the actuator while maintaining measurement capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the shape memory alloy transitions at a higher transformation temperature during debris-covered conditions, then the actuator can detect the presence of debris, but the energy consumption increases

Engineering Contradiction:

Improvedebris detection reliabilityVSAvoidthermal energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The thermal energy from the debris (ice or mud) that would normally be considered a harmful condition is converted into a useful signal. The debris's thermal properties cause the shape memory alloy to transition at a higher temperature, which reliably indicates debris presence while utilizing the debris's own thermal energy rather than requiring additional heating.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 reliable detection of debris and automatic cleaning, ensuring optimal vehicle component functionality and line of sight without manual intervention, improving operational efficiency and convenience.

Implementation Method 1

The actuator is formed from a shape memory alloy transitionable in response to a thermal activation signal between a first temperature-dependent state and a second temperature-dependent state

Methodology Applied

Scientific EffectShape memory alloy transition: Shape Memory Alloy

Implementation Method 2

a resilient member configured for translating the plunger within the cavity after the shape memory alloy transitions from the second temperature-dependent state to the first temperature-dependent state

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS8997563B2Vehicle sensor system

Publication Date: 2015.04.07 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A sensor system includes a housing defining a cavity, an actuator formed from an alloy transitionable between first and second states, a plunger attached to the actuator, and a resilient member configured for translating the plunger within the cavity. The plunger is not translatable during a first condition in which a coating of debris is disposed on the housing as the alloy transitions between the first and second states to define a first stress on the actuator. The plunger is translatable during a second condition in which the housing is substantially free from the coating as the alloy transitions to define a second stress on the actuator that is less than the first stress. The alloy transitions from the first to the second state at a first transformation temperature during the first condition, and at a second transformation temperature that is less than the first temperature during the second condition.