Exhaust Temperature Rate of Change for Aftertreatment Theft Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional anti-theft devices for exhaust after-treatment systems in internal combustion engines cannot detect the removal of the system from the exhaust pipe without cutting the electrical wiring of the temperature sensor, leading to ineffective theft detection.
Innovation Solution
A control device is implemented in the internal combustion engine that calculates the temperature of exhaust flowing into and out of the exhaust after-treatment system, determining the rate of change over time for both temperatures, and uses this information to judge if the system has been removed from the exhaust pipe by analyzing the difference between these rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical wiring cutting detection is used to detect exhaust after-treatment system removal, then theft detection capability is improved, but detection reliability deteriorates when wiring is not cut
Solution Approach 1:
The patent changes the detection parameter from electrical wiring integrity to exhaust temperature characteristics. By monitoring the rate of change of exhaust temperature and comparing it between upstream and downstream of the after-treatment system, the system can detect removal without relying on electrical wiring status, thus resolving the contradiction between theft detection capability and detection accuracy
Solution Approach 2:
The patent replaces the electrical detection system (wiring cut detection) with a thermal detection system (exhaust temperature monitoring). This substitution allows detection of system removal based on thermal characteristics rather than electrical continuity, eliminating the false negative problem when wiring is not cut
2Object-affected harmful factors
If temperature sensor wiring is monitored for theft detection, then anti-theft function is improved, but false negatives occur when wiring remains intact
Solution Approach 1:
The detection parameter is changed from electrical wiring status to exhaust temperature rate of change. This allows the system to reliably detect removal events regardless of wiring integrity, eliminating false negatives while maintaining theft prevention capability
Solution Approach 2:
The exhaust temperature serves as an intermediary parameter that indirectly indicates the presence or removal of the after-treatment system. By monitoring how the exhaust temperature changes as it passes through the system, the system can detect removal without directly monitoring wiring integrity
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 solution allows for accurate detection of the removal of the exhaust after-treatment system from the exhaust pipe, enhancing theft prevention and reducing false positives due to sensor placement variations.
Implementation Method 1
it is possible to utilize a heat capacity of an exhaust after-treatment system to detect removal of an exhaust after-treatment system from an exhaust pipe
Data Source
AI summary
A control device comprising a first exhaust temperature calculation part calculating a temperature of exhaust flowing into a PM trapping device as a first exhaust temperature, a second exhaust temperature calculation part calculating a temperature of exhaust flowing out from the PM trapping device as a second exhaust temperature, a rate of change over time calculation part calculating a rate of change over time of the first exhaust temperature and a rate of change over time of the second exhaust temperature, and a judgment part judging if the PM trapping device is in a removed state removed from the exhaust passage based on a difference between the rate of change over time of the first exhaust temperature and the rate of change over time of the second exhaust temperature.