| 摘要 |
A stroke determination unit for a 4 -cycle engine uses intake pressure as a parameter to provide accurate stroke determination. A combined pressure combines the detected pressures of intake ports of the first to third cylinders, and stroke determination is carried out by recognizing, within a combined pressure waveform based on a detection value for the combined pressure, shapes of the combined pressure waveform for a specified phase period of a crankshaft. The pressure pattern recognition is carried out by storing variation patterns of pressure values measured within the specified crankshaft phase period, and collating patterns with a data map stored within an ECU. Alternatively, the pattern recognition is carried out by collating with condition equations representing "rising" or "upward peak". With the latter, pressure variation due to contamination such as electrical noise to the pressure sensor is made negligible, and noise suppression of the stroke determination unit is improved.
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