Engine Controller Detects Detached Exhaust Purification Device
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Solution Overview
Problem
Existing controllers for internal combustion engines face challenges in accurately determining if an exhaust purification device, such as a particulate matter filter, is detached from the exhaust passage, leading to inaccuracies in anomaly detection.
Innovation Solution
A controller with processing circuitry that calculates temperature change amounts on both sides of the exhaust purification device during a fuel cutoff operation and determines if the deviation between these changes is within a threshold, indicating the device's attached or detached state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the controller compares temperature changes to detect filter removal, then anomaly detection capability is provided, but measurement precision is insufficient leading to inaccurate detection
Solution Approach 1:
The patent changes the parameter being measured from absolute temperature to temperature change rate (differential value). By calculating the differential value between upstream and downstream temperature changes, the system achieves more precise detection of filter removal anomalies. This parameter transformation allows the system to detect subtle thermal differences that indicate filter detachment, thereby improving measurement precision and detection accuracy simultaneously.
2Measurement precision
If the controller uses simple temperature comparison, then device complexity is low, but detection accuracy is insufficient
Solution Approach 1:
The controller performs preliminary calculations of temperature change rates for both upstream and downstream sides before comparing them. By pre-calculating the differential values and storing them for comparison, the system achieves high detection accuracy without requiring complex real-time processing during the actual detection moment. This preliminary action approach maintains relatively simple device architecture while improving measurement precision.
3Reliability
If the exhaust purification device is detached, then exhaust gas flows freely without thermal capacity effects, but anomaly detection becomes difficult to distinguish from normal operation
Solution Approach 1:
The system continuously monitors and compares the differential values of temperature changes between upstream and downstream sides, creating a feedback mechanism that distinguishes normal thermal capacity effects from abnormal filter removal conditions. By establishing reference ranges for the differential values during normal operation, the system can reliably detect anomalies when the values fall outside these ranges, thereby improving detection reliability without requiring additional thermal capacity information.
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 enhances the accuracy of anomaly detection by differentiating between the device being attached or detached based on temperature change deviations, improving the reliability of exhaust purification system monitoring.
Implementation Method 1
The heat of the exhaust gas conducted into the exhaust purification device is consumed by heat exchange with the exhaust purification device.
Data Source
AI summary
A controller for an internal combustion engine is configured to execute a determination process and an anomaly diagnosing process. The determination process is a process of determining that a deviation between a first change amount and a second change amount during a fuel cutoff operation is less than or equal to a threshold. The anomaly diagnosing process is a process of determining that an exhaust purification device is in a detached state when it is determined in the determination process that the deviation is less than or equal to the threshold. The first change amount and the second change amount are change amounts per unit time of the temperature of exhaust gas on the upstream side and the downstream side of the exhaust purification device, respectively.