EGR Effective Flow Diagnosis Using Temperature Rise

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Solution Overview

Problem

Conventional methods for diagnosing EGR system effectiveness, such as comparing flows calculated by MAP and MAF sensors, often result in errors, leading to incorrect diagnoses of EGR system clogging or opening.

Innovation Solution

The proposed method involves measuring EGR differential pressure and gas temperature using sensors, calculating effective flow based on temperature rise, and determining valve positions to accurately diagnose EGR system clogging or opening by establishing relationships between flow and valve positions, thereby avoiding sensor-related errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If EGR effective flow is determined by calculating the difference between MAP sensor flow and MAF sensor flow, then the diagnosis method is simple to implement, but the measurement precision deteriorates due to large errors between the two sensors

Engineering Contradiction:

Improvediagnosis method simplicityVSAvoidEGR effective flow measurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical/sensor-based flow measurement system (MAP and MAF sensors) with a thermal-based measurement system using an EGR temperature sensor. Instead of calculating flow through pressure differential sensors, the system measures the temperature increase of EGR gas to determine effective flow, thereby avoiding the measurement errors inherent in the sensor-based differential calculation method

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from pressure-based flow calculation (using MAP and MAF sensors) to temperature-based flow measurement (using EGR temperature sensor). By measuring the temperature rise of EGR gas and correlating it with flow rate, the system achieves more accurate measurement without the errors associated with differential pressure sensor calculations

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If conventional sensor-based EGR flow diagnosis is used, then device complexity is low, but reliability deteriorates due to incorrect diagnosis of EGR clogging or opening

Engineering Contradiction:

Improvediagnosis system complexityVSAvoidEGR system diagnosis accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent replaces the unreliable sensor-based diagnosis system with a thermal measurement system. By using the EGR temperature sensor to measure gas temperature and infer flow effectiveness, the system achieves more reliable diagnosis of EGR clogging or opening conditions without significantly increasing overall system complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces temperature measurement as an intermediary parameter to diagnose EGR flow effectiveness. Instead of directly measuring flow or relying on differential pressure calculations, the system uses temperature rise of the EGR gas as an intermediate indicator that reliably indicates whether EGR flow is effective or blocked

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach enhances the accuracy of EGR effective flow diagnosis, preventing misdiagnosis and maintaining fuel efficiency by correctly identifying EGR system abnormalities.

Implementation Method 1

measuring an EGR gas temperature by an EGR gas temperature sensor

Methodology Applied

Scientific EffectTemperature measurement:

Implementation Method 2

checking an EGR differential pressure by an EGR pressure sensor on an intake line

Methodology Applied

Scientific EffectDifferential pressure measurement:

Data Source

PatentUS11492951B2EGR effective flow diagnosis method

Publication Date: 2022.11.08 HYUNDAI MOTOR CO LTD

AI summary

An Exhaust Gas Recirculation (EGR) effective flow diagnosis method includes: measuring an EGR gas temperature by an EGR gas temperature sensor under an EGR gas temperature rise condition of an EGR system on an intake line; determining the degree of the EGR gas temperature rise; and determining whether an EGR effective flow is excessive or insufficient according to the degree of the EGR gas temperature rise.