| 摘要 |
PURPOSE:To set a timer mechanism at a target position, by executing a process for judging stable idling conditions of an engine, a process for storing actual-position data obtained by a timer position sensor as a learnt value, and a process for correcting the learnt value. CONSTITUTION:A control circuit 8 has an input buffer 9 at the input side, an output buffer 10 at the output side, and an MPU11, a ROM12 and a RAM13 at its middle section. In case that it is judged that the idling operation is stable, a timer piston 59 is moved to the right-side end by fully opening a timer control valve 6 and leaking oil in a high-pressure oil chamber 60 of a timer mechanism 58 into a low-pressure oil chamber 61. The mean value of a predetermined number of input data is calculated by taking out the output signal of a timer position sensor 7 and the learnt value obtained from the calculation is stored in the RAM13. When the idling operation becomes unstable, datum-position data is calculated from a data map of the datum timer position using engine-speed data and load data as parameters, and the timer mechanism is set at a target position by calculating the duty ratio of a pulse having a prescribed frequency from the data relating to the target timer position and the data relating to its actual position. |
