| 摘要 |
An object of this invention is to promptly detect a crank angle based on in-cylinder pressures and easily compensate for a detection error by processing that has a low computational load. An ECU 50 calculates an in-cylinder pressure ratio (P n+1 /P n ) based own in-cylinder pressures P n and P n+1 at two crank angles separated by a predetermined angle ”¸. The ECU 50 includes map data that represents relations between volume ratio parameters (V n º /V n+1 º ) calculated using in-cylinder volume V n and V n+1 at the crank angles, and the crank angles. Therefore, when cranking, a crank angle can be detected based on the in-cylinder pressure ratio and the map data earlier than a conventional cylinder discrimination operation. Gains included in the in-cylinder pressures P n and P n+1 can be removed by dividing the two pressures, and exponential operations and the like can be eliminated by using the map data to thus suppress the computational load. |
