Engine Start Diagnosis via Crankshaft Speed Threshold
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Solution Overview
Problem
Existing engine start abnormality diagnosis systems are inefficient in quickly identifying the cause of long cranking abnormalities, which prolongs troubleshooting and repair time, as they struggle to distinguish between combustion and electric system abnormalities during the engine starting process.
Innovation Solution
An engine start abnormality diagnosis apparatus equipped with a rotation speed detector and an abnormality diagnosis processor that determines the cause of long cranking abnormalities by comparing the rotation speed of the crankshaft during the latter stage of the compression stroke with a predetermined threshold, distinguishing between electric system and combustion abnormalities based on the detected speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing engine start abnormality diagnosis systems are used, then the diagnosis process can identify long cranking abnormalities, but the troubleshooting and repair time is prolonged due to inability to quickly distinguish between combustion and electric system abnormalities
Solution Approach 1:
The diagnosis method segments the abnormality identification process by detecting crankshaft rotation speed at specific engine phases (compression stroke, expansion stroke, exhaust stroke, intake stroke) and comparing the speeds across different phases. This phase-based segmentation enables precise identification of whether the abnormality originates from combustion or electric system issues, significantly improving diagnostic accuracy while reducing troubleshooting time
Solution Approach 2:
The system performs preliminary detection of crankshaft rotation speed during the compression stroke phase, which occurs early in the engine cycle. By detecting and comparing rotation speeds at this preliminary stage with subsequent phases, the system can quickly determine the abnormality cause before completing full troubleshooting procedures, thereby reducing overall diagnostic time
Data Source
AI summary
An engine start abnormality diagnosis apparatus determines a cause of a long cranking abnormality in which, when an engine including cylinders is started, start of the engine is not completed even if a cranking period is equal to or greater than a predetermined time. The engine start abnormality diagnosis apparatus includes a rotation speed detector and an abnormality diagnosis processor. The rotation speed detector detects a rotation speed of a crankshaft of the engine when at least one of the cylinders is in a latter stage of a compression stroke. The abnormality diagnosis processor determines that the cause of the long cranking abnormality is an electric system abnormality when the rotation speed is less than a predetermined threshold, and determines that the cause of the long cranking abnormality is a combustion abnormality when the rotation speed is equal to or greater than the threshold.