Particle Sensor Offset Detection in Vehicle Exhaust Filters
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Solution Overview
Problem
Existing methods for monitoring the functionality of particle filters in vehicle engines fail to reliably detect systematic offset errors in particle sensors, leading to incorrect filter diagnosis and potential non-detection of defective filters.
Innovation Solution
A method involving measuring particle concentration downstream of the particle filter at two distinct engine operating points, determining filter efficiency levels at each point, and detecting an offset error if the absolute difference between these levels exceeds a defined threshold, thereby accounting for potential sensor offset errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a particle sensor is used to monitor filter functionality, then filter damage can be detected, but systematic offset errors in the sensor lead to incorrect measurements and false diagnosis
Solution Approach 1:
The method changes the operating parameters of the engine to create two distinct operating points with different particle concentrations upstream of the filter. By comparing measurements at these different parameter states, the system can distinguish between actual filter performance changes and sensor offset errors, thereby resolving the measurement precision issue while maintaining reliability
Solution Approach 2:
The system uses feedback from particle concentration measurements at two different operating points to detect and compensate for sensor offset errors. The comparison of filter efficiency levels at different operating conditions creates a feedback mechanism that identifies systematic errors and prevents false diagnosis
2Loss of information
If filter efficiency is determined from particle concentration measurements, then filter functionality can be assessed, but sensor offset errors cause incorrect efficiency calculations
Solution Approach 1:
By varying the operating point of the engine to achieve different particle concentrations upstream of the filter, the method creates multiple measurement conditions. This parameter change allows the system to calculate filter efficiency at different operating points and detect offset errors that would otherwise corrupt the efficiency information
Solution Approach 2:
The method uses an excessive action by measuring at two operating points instead of one, which provides redundant information. This extra measurement allows the system to detect and compensate for offset errors, ensuring accurate filter efficiency assessment even when individual measurements are affected by sensor errors
Data Source
AI summary
The present disclosure relates to engines for a motor vehicle and some embodiments include a method for operating an exhaust train of a motor vehicle engine including: measuring a particle concentration downstream of a particle filter at a first operating point; determining the filter efficiency at the first operating point; changing operation of the engine to a second operating point to increase the particle emissions; measuring the particle concentration downstream of the filter at the second operating point; determining the filter efficiency at the second operating point; determining a difference between the efficiency levels; detecting an offset error, if the difference exceeds a defined threshold; and identifying a particle sensor as defective if an offset error is detected, rather than identifying the particle filter as defective.