Engine Misfire Diagnosis via Pattern Segmentation
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Solution Overview
Problem
Existing engine fault diagnosis methods for misfires are time-consuming and inefficient, particularly when misfires are non-repeating or difficult to replicate, making it challenging to identify faulty regions in multicylinder engines.
Innovation Solution
A fault diagnosing method and system that uses an external diagnosing machine to communicate with the engine control unit, detecting misfire patterns and tracking down faulty regions by analyzing diagnostic fault codes, engine data, and repeating misfire conditions, including compression pressure and air-fuel ratio tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a test is conducted on each region that may possibly be responsible for a misfire, then the faulty region can be identified, but the diagnosis becomes highly tedious and time-consuming
Solution Approach 1:
The patent segments the misfire diagnosis process by classifying misfires into distinct patterns (successive misfires, random misfires, single-cylinder misfires, multi-cylinder misfires). Each pattern corresponds to specific faulty regions, allowing the diagnosis to focus on relevant areas rather than testing all regions uniformly. This segmentation enables the system to identify the faulty region efficiently by matching the observed misfire pattern to predefined categories.
Solution Approach 2:
The patent performs preliminary classification of misfire patterns before conducting detailed regional testing. By first detecting and categorizing the misfire pattern using the misfire detecting function, the system prepares the diagnosis pathway in advance. This preliminary action eliminates the need for exhaustive testing of all regions, as the classification guides which specific regions should be investigated next.
2Measurement precision
If a misfire test is performed to identify faulty regions, then the faulty region can be tracked down, but the test becomes difficult to perform if the misfire is not repeated or is difficult to repeat
Solution Approach 1:
The patent employs feedback mechanisms where the misfire detecting function continuously monitors engine operation and provides real-time data about misfire occurrences. The system uses this feedback to classify misfire patterns and update the diagnosis accordingly. Even if misfires are not repeated during testing, the feedback from initial misfire detection allows the system to identify patterns and proceed with targeted diagnosis of the faulty region.
Solution Approach 2:
The misfire detecting function serves itself by automatically detecting, classifying, and providing data for diagnosis without requiring manual intervention to induce or observe repeated misfires. The system leverages naturally occurring misfires and uses its own detection capabilities to generate the necessary diagnostic information, eliminating the need for external testing procedures that require misfire repetition.
3Measurement precision
If comprehensive tests are conducted to track down faulty regions, then diagnostic accuracy is improved, but the number of man-hours required increases significantly
Solution Approach 1:
The patent creates a universal misfire classification system that handles multiple types of misfires (successive, random, single-cylinder, multi-cylinder) through a single integrated approach. The misfire detecting function serves multiple purposes: detecting misfires, classifying patterns, and guiding diagnosis. This multi-functionality eliminates the need for separate testing procedures for different misfire types, significantly improving diagnosis efficiency while maintaining comprehensive coverage.
Solution Approach 2:
The patent changes the diagnostic parameter from exhaustive regional testing to misfire pattern classification. By shifting the basis of diagnosis from physical region-by-region testing to analyzing temporal and spatial patterns of misfires, the system achieves high diagnostic accuracy with minimal intervention. This parameter change transforms the diagnosis from a time-intensive physical testing process to an efficient data analysis process.
Data Source
AI summary
In the present fault diagnosis method and the fault diagnosis system for an engine, an external diagnosis device: obtains continuous data on the incidences of misfire by misfiring cylinders from the vehicle's side with regard to the actually occurring misfire or past incidences of misfire; detects a misfire pattern, which is to be classified according to the presence of continuous incidences of misfire, on the basis of the continuous data; and narrows down a fault site in accordance with the misfire pattern.