Crankshaft Rotation Direction Diagnosis in Engine Control
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Solution Overview
Problem
Existing control apparatuses for internal-combustion engines face inaccuracies in determining the rotating direction of the crankshaft, leading to incorrect crank angle detection and subsequent fuel injection and ignition issues, resulting in abnormal combustion and deteriorated exhaust properties.
Innovation Solution
A control apparatus that diagnoses the proper determination of the crankshaft's rotating direction by comparing the crank angle detected at engine stop with the estimated crank angle after starting, using a combination of crank angle and cam sensors to accurately determine forward or reverse rotation, thereby preventing incorrect fuel injection and ignition control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotation sensor is used to determine the rotating direction of the crankshaft, then the rotating direction can be detected, but variations and deterioration of the sensor or circuits lead to inaccurate pulse width and amplitude measurements, resulting in incorrect determination of the rotating direction
Solution Approach 1:
The system uses feedback by comparing the detected crank angle at engine stop with the estimated crank angle after engine start. This comparison provides feedback on whether the rotating direction was correctly determined, allowing the system to identify and correct determination errors without being directly affected by sensor variations.
Solution Approach 2:
The system performs preliminary detection of the crank angle at the moment of engine stop before the actual engine start. This preliminary action stores reference information that is later used to verify the correctness of rotating direction determination, enabling error detection before fuel injection and ignition are activated.
2Productivity
If the rotating direction is incorrectly determined, then the crank angle detection becomes incorrect, but the system continues to control fuel injection and ignition based on this incorrect information, causing abnormal combustion and deteriorated exhaust properties
Solution Approach 1:
The system performs preliminary detection and storage of the crank angle at engine stop before the engine is restarted. This preliminary action allows the system to prepare accurate reference information for fuel injection and ignition timing, preventing abnormal combustion while maintaining quick starting responsiveness.
Solution Approach 2:
The system implements a feedback mechanism that compares the detected crank angle with the estimated crank angle after engine start. This feedback loop identifies determination errors and prevents incorrect fuel injection and ignition control, thereby avoiding abnormal combustion and deteriorated exhaust properties.
Data Source
AI summary
A control apparatus and a control method diagnose whether an internal-combustion engine is rotated in forward or reverse directions is being properly implemented. Specifically, based on a pulse width WIPOS of a rotation signal POS output by a crank angle sensor, it is determined whether a crankshaft is rotated in the forward or the reverse directions. Based on the determination of the rotating direction of the crankshaft, a counter CNTPOS, which denotes a count value of rotation signal POS, is updated. At the time of restarting the engine, counter CNTPOS is updated, using a value on counter CNTPOSz at the time of stopping the engine as an initial value. If the value on counter CNTPOS at a crank angle position determined after the starting of the engine differs from an expected value, then the function for determining the rotating direction of the crankshaft is diagnosed to be abnormal.