Electrically Heated Catalyst Insulation Diagnosis
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Solution Overview
Problem
Existing exhaust gas purifying devices for internal combustion engines require multiple insulation resistance measurements during a vehicle trip to diagnose the state of electrically heated catalysts, leading to high power consumption.
Innovation Solution
An exhaust gas purifying device that acquires insulation resistance values at the start of each trip and uses index values or ratios to diagnose insulation abnormalities, reducing the need for multiple measurements within a trip, thereby minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple insulation resistance measurements are performed during a vehicle trip to diagnose the state of the electrically heated catalyst, then the diagnostic accuracy is improved, but the electric power consumption increases
Solution Approach 1:
The insulation resistance value is measured in advance at the start of each trip before the catalyst warm-up process begins. This preliminary measurement allows the diagnostic system to have baseline data available without requiring continuous measurements during the trip, thereby reducing power consumption while maintaining diagnostic capability.
Solution Approach 2:
The system compares the insulation resistance value measured at the current trip start with values from previous trips to determine whether insulation abnormality has occurred. This feedback mechanism enables accurate diagnosis by detecting changes in insulation resistance over time without requiring multiple measurements within a single trip.
2Use of energy by moving object
If insulation resistance value is measured only at the start of each trip, then the electric power consumption is reduced, but the ability to detect insulation abnormalities during the trip is weakened
Solution Approach 1:
The insulation resistance measurement is performed in advance at trip start, establishing a baseline value before catalyst operation begins. This preliminary action ensures that the measurement is taken when the catalyst is in a known state, improving the reliability of abnormality detection while minimizing power consumption.
Solution Approach 2:
The diagnostic processing compares the current trip's insulation resistance value with values from previous trips to detect insulation abnormalities. This inter-trip feedback mechanism compensates for the reduced measurement frequency by using historical data to identify trends and abnormalities that would indicate catalyst issues.
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
The device effectively diagnoses insulation abnormalities while significantly reducing electric power consumption for diagnosis, allowing for efficient carbon removal processing when necessary.
Implementation Method 1
a heating element arranged in an exhaust gas passage of an internal combustion engine and configured to generate heat when energized to heat a catalyst
Implementation Method 2
an insulation resistance detector configured to detect an insulation resistance value of the insulating member
Data Source
AI summary
An exhaust gas purifying device for an internal combustion engine includes: an electrically heated catalyst (EHC) including an insulating member; an insulation resistance detector; and a processor. The processor is configured to: acquire an insulation resistance value of the insulating member using the insulation resistance detector each time a trip of the vehicle starts; and execute diagnostic processing to diagnose the state of the EHC when the acquired insulation resistance value is equal to or less than a reference value. In the diagnostic processing, the processor is configured to determine whether or not there is an insulation abnormality of the EHC, based on an index value indicating the degree of decrease in an insulation resistance value of the insulating member of the current trip with respect to an insulation resistance value of the insulating member of one or more past trips including the last trip.