EGR Reverse Hose Diagnostic via Flow Dominance

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Solution Overview

Problem

Current methods for executing reverse hose diagnostics in EGR systems are prone to inaccuracies due to ghost flow noise, especially when the EGR valve is closed, leading to incomplete or misleading results.

Innovation Solution

Executing the reverse hose diagnostic when the EGR flow rate exceeds a threshold, with the EGR valve open, to minimize the impact of ghost flow noise and ensure more accurate delta pressure measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the reverse hose diagnostic is executed with the EGR valve closed, then the diagnostic can be performed without EGR flow, but the ghost flow noise causes inaccurate or incomplete diagnostic results

Engineering Contradiction:

Improveease of executing reverse hose diagnosticVSAvoidaccuracy of delta pressure measurement

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the operational parameter of the EGR valve from closed position to open position during the reverse hose diagnostic. By opening the EGR valve to allow actual EGR flow, the system transforms the diagnostic condition from a static no-flow state to a dynamic flow state, where the real EGR flow dominates over ghost flow noise and provides accurate delta pressure measurements for hose orientation determination

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the previously harmful effect of requiring EGR valve closure into a beneficial condition. Instead of closing the valve which creates ghost flow noise problems, the system opens the valve to allow genuine EGR flow, which then serves as the dominant signal that overrides the ghost flow noise, transforming the diagnostic challenge into a solution where actual flow becomes the advantage

Inventive Principle:

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

2Measurement precision

If the delta pressure sensor is positioned upstream of the EGR valve, then the sensor can measure EGR flow, but contaminants in the EGR degrade the sensor

Engineering Contradiction:

Improveability to measure EGR flowVSAvoidsensor durability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent inverts the traditional sensor positioning approach. Instead of placing the delta pressure sensor upstream of the EGR valve where it would be exposed to hot EGR contaminants, the sensor is repositioned downstream of the EGR valve. This inversion allows the sensor to measure the pressure differential caused by EGR flow indirectly, while being protected from the harsh thermal and chemical environment of the exhaust gas

Inventive Principle:

Principle #13The other way round (Inversion)

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 increases the likelihood of completing the diagnostic successfully by ensuring that EGR flow dominates over ghost flow noise, resulting in more reliable hose orientation determination and reduced errors in EGR system diagnostics.

Implementation Method 1

a delta pressure sensor downstream of the EGR valve between the EGR valve and an intake manifold... sensing a delta pressure via the delta pressure sensor

Methodology Applied

Scientific EffectPressure differential measurement: Pressure Gradient

Data Source

PatentUS11215532B2Methods and systems for exhaust gas recirculation system diagnostics

Publication Date: 2022.01.04 FORD GLOBAL TECH LLC

AI summary

Methods and systems are provided for an EGR system reverse hose diagnostic. In one example, a method includes executing the reverse hose diagnostic in response to an EGR flowrate exceeding a threshold flow rate.