Exhaust Gas Flap Fault Detection via Oxygen Variation

Solution Overview

Problem

Existing methods for checking the exhaust gas flap on a turbocharger are inadequate in accurately determining faults, as they rely on position feedback and cannot distinguish between faulty valve operation and other issues like leaks or contamination, which can lead to unsafe engine behavior.

Innovation Solution

A method involving variation of the fuel-to-air ratio in the fresh gas supplied to the internal combustion engine and determination of residual oxygen content in the exhaust gas system to identify if the valve is faulty by comparing the variation of residual oxygen content with a predetermined pattern, allowing for targeted detection of valve faults without position feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If position feedback is used to monitor exhaust gas flap position, then the position can be determined, but it is still not possible to distinguish between faulty valve operation and other issues like leaks or contamination

Engineering Contradiction:
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces exhaust gas oxygen content as an intermediary parameter to indirectly assess valve functionality. Instead of directly measuring valve position or relying on position feedback alone, the system measures oxygen content in the exhaust gas, which serves as a mediator that reflects the actual flow conditions and valve operation status, enabling distinction between valve faults and other issues.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback mechanism by continuously monitoring exhaust gas oxygen content and comparing it against expected values or trends. This feedback loop allows the system to detect deviations indicating valve faults and trigger appropriate responses, improving reliability beyond simple position monitoring.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If boost pressure observation is used for plausibility checking, then operation can be monitored, but specific faults cannot be identified due to similar effects from different issues

Engineering Contradiction:
Core Design Contradiction:
Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent changes the measurement parameter from boost pressure alone to exhaust gas oxygen content. This parameter change provides more specific information about valve operation, as oxygen content directly reflects the exhaust gas flow distribution affected by valve position, enabling specific fault identification while maintaining ease of operation through existing sensor infrastructure.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If exhaust gas flap position is monitored, then turbocharger power control can be ensured, but unsafe engine behavior may occur if faults are not accurately detected

Engineering Contradiction:
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical position feedback systems with a chemical/physical measurement approach using exhaust gas oxygen content analysis. This substitution provides more reliable information about actual valve functionality and flow conditions, improving turbocharger power control reliability and preventing unsafe engine behavior by accurately detecting valve faults.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enables precise identification of exhaust gas turbocharger faults, enabling continued engine operation and targeted maintenance, while reducing the risk of unsafe engine behavior by distinguishing between valve faults and other issues.

Implementation Method 1

variation of a fuel-to-air ratio in a fresh gas supplied to the internal combustion engine

Methodology Applied
Scientific EffectFuel-to-air ratio variation:

Implementation Method 2

determination of a residual oxygen content in the exhaust gas system

Methodology Applied
Scientific EffectResidual oxygen content determination:

Implementation Method 3

an exhaust gas flow exits the internal combustion engine, a first portion of said flow flowing through a turbine of the exhaust gas turbocharger into an exhaust gas system

Methodology Applied
Scientific EffectExhaust gas flow: Convection

Data Source

PatentUS9016062B2Checking an exhaust gas flap
Publication Date: 2015.04.28
  • US9016062B2 patent drawing
  • US9016062B2 patent drawing
  • US9016062B2 patent drawing

AI summary

A method is disclosed for checking a valve on an exhaust gas turbocharger of an internal combustion engine, wherein an exhaust gas flow exits the internal combustion engine, a first portion of said flow flowing through a turbine of the exhaust gas turbocharger into an exhaust gas system and a second portion flowing through the valve into the exhaust gas system, wherein said method includes the steps of varying a fuel-to-air ratio in a fresh gas supplied to the internal combustion engine, determining a residual oxygen content in the exhaust gas system, and determining that the valve is defective if a variation of the residual oxygen content occurs in a manner different than a predetermined manner of the variation of the fuel-to-air ratio in the fresh gas. A device for checking the valve can be integrated into an integrated engine control unit of the internal combustion engine.