Exhaust Sensor Cooling Verification Without Battery Drain

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Solution Overview

Problem

Existing engine control systems for diesel engines lack the necessary hardware to verify sensor functionality without drawing power from the vehicle battery, making it difficult to ensure sensors are 'cold' before diagnostic testing as required by regulations.

Innovation Solution

A method that processes temperature data from sensors along the exhaust gas flow path to determine if sensors have cooled sufficiently, allowing diagnostic testing to proceed without relying on battery power by using a processor to analyze temperature differences and reference values, thus avoiding the need for 'keep alive memory' or similar features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a timer is used to measure engine off time to verify sensor functionality, then sensor cold status can be confirmed, but power must be drawn from the vehicle battery to run the timer

Engineering Contradiction:

Improvesensor functionality verificationVSAvoidbattery power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces the electrical timer-based measurement system with a thermal-based measurement system. Instead of using an electrical timer that consumes battery power, the system uses temperature sensors to measure the thermal state of the exhaust system, which indirectly indicates whether the engine has been off long enough for sensors to cool down. This substitution eliminates the need for continuous battery power during engine-off periods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The exhaust system itself serves as the measurement medium. The thermal mass and cooling rate of the exhaust system naturally provide information about engine off-time without requiring external power sources. The system uses its own thermal characteristics to determine when sensors are ready for testing, making the measurement process self-powered.

Inventive Principle:

Principle #25Self-service

2Reliability

If keep alive memory or similar hardware features are added to measure engine off time, then sensor functionality can be verified, but device complexity increases

Engineering Contradiction:

Improvesensor functionality verificationVSAvoidhardware requirements

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex electrical hardware (keep alive memory, timers, power management circuits) with simple thermal sensing hardware. Temperature sensors are already present in exhaust systems for other purposes, and their data can be repurposed to determine sensor readiness, eliminating the need for dedicated time-measurement hardware.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent makes existing temperature sensors serve multiple functions: their primary function for exhaust temperature monitoring and a secondary function for determining sensor cold status. This multi-functionality eliminates the need for separate hardware components dedicated solely to time measurement.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7533519B2Three sensor comparison rationality test

Publication Date: 2009.05.19 INT ENGINE INTPROP CO LLC

AI summary

Testing of temperature sensors (28, 30, 32) in an emission control system, such as in an exhaust system (10) of a diesel engine, serves to condition further component and/or system testing by determining that sufficient sensor cooling has occurred and that no sensor is “stuck within range” using a strategy (50).