| 摘要 |
PURPOSE:To make ignition timing determinable without using a crank angle sensor by performing ignition at a time when output of a cylinder internal pressure sensor has reached a cylinder internal pressure calculated value corresponding to an ignition timing crank angle. CONSTITUTION:At a microcomputer 14, reference ignition timing corresponding to intake pressure out of an intake pressure sensor 4 and engine speed out of an ignition period is read out of a reference ignition timing map stored in a read-only memory 6. Next, optimum timing data at a combustion pressure peak position are read out of intake pressure and engine speed maps stored in the read-only memory 6. In succession, a difference mean value at the combustion pressure peal position is calculated, and thereby an ignition timing compensation value is operated, compensating the reference ignition timing. Then, an operation resulting value of cylinder internal pressure corresponding to the ignition timing after compensation calculated out of the intake pressure is compared with an output value of the cylinder internal pressure sensor 14 by a comparator 18, and if both values are accorded with each other, an igniter 11 is driven and ignition takes place. With this constitution, ignition timing control is performed without using a crank angle sensor. |
