Oxygen Sensor Diagnostics and Cleaning Method
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Solution Overview
Problem
Existing oxygen sensors in combustion engine vehicles are often unnecessarily replaced due to inert gas pollution, which can be mistaken for malfunctions, leading to unnecessary costs and handling.
Innovation Solution
A method that differentiates between sensor malfunctions and inert gas clogging by varying the fuel richness level setpoint and measuring oxygen and voltage variations, allowing for sensor cleaning and accurate malfunction detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor is packaged in an inert atmosphere to prevent oxidation of electrodes, then the sensor is protected from oxidation, but inert gases deposit on the electrodes causing measurement errors
Solution Approach 1:
The system performs preliminary diagnostic actions by varying the richness level setpoint and monitoring sensor responses before concluding the sensor is malfunctioning. This preliminary testing distinguishes between inert gas deposition and actual sensor failure, preventing premature replacement decisions
Solution Approach 2:
The sensor cleaning function allows the sensor to restore its own functionality by removing inert gas deposits through controlled heating and air supply, eliminating the need for manual intervention or premature replacement
2Reliability
If the control unit systematically advises sensor replacement when measurements are irrelevant, then false malfunctions due to inert gas pollution are identified, but unnecessary sensor replacements occur generating costs and handling
Solution Approach 1:
Before advising sensor replacement, the system performs preliminary diagnostic tests by varying the richness level setpoint and analyzing the sensor's voltage and oxygen level responses. This preliminary action distinguishes between inert gas deposition and actual sensor failure
Solution Approach 2:
The system uses feedback from the sensor's response to richness level variations to determine whether the sensor is merely clogged with inert gases or actually malfunctioning. The counter mechanism provides feedback on the number of cleaning cycles performed
3Measurement precision
If the richness level setpoint is varied to diagnose sensor status, then accurate differentiation between clogging and malfunction is achieved, but additional control steps and time are required
Solution Approach 1:
The system uses periodic variation of the richness level setpoint to elicit diagnostic responses from the sensor. By periodically changing the richness level and monitoring the sensor's voltage and oxygen level responses, the system efficiently diagnoses sensor status without requiring continuous complex testing
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 method reduces unnecessary sensor replacements by accurately distinguishing between clogging and malfunctions, ensuring only necessary replacements and allowing for sensor cleaning, thereby minimizing costs and handling.
Implementation Method 1
a sensor placed between the outlet of the engine and the inlet of the depollution system and configured to measure a parameter relating to the oxygen level in the exhaust gases exiting the engine, the sensor comprising two voltage measurement terminals
Implementation Method 2
the combustion phase of the combustion engine
Data Source
AI summary
This relates to a method for diagnosing a sensor for a motor vehicle, and to the vehicle, the method including: a) a step of detecting errors in the measurements taken by the sensor; b) a first phase of commanding the cleaning of the sensor; and c) a step of cancelling the detection of measurement errors by the sensor if the difference between the first variation in the richness level determined on the basis of the parameter relating to the pumping current and the second variation determined on the basis of the variation in the voltage across the terminals of the sensor is: i) less than a predefined maximum tolerance threshold; and ii) greater than a predefined minimum tolerance threshold.