| 摘要 |
PURPOSE:To enable continuation of operation even if a crank angle sensor breaks down by calculating ignition timing from an output signal of cylinder internal pressure detecting means when rotary position detecting means breaks down to conduct ignition according to the calculation result. CONSTITUTION:When a crank angle sensor 1 breaks down, an engine is ignited according to an output signal from a cylinder internal pressure sensor 13. That is, an output signal of the cylinder internal pressure sensor 13 is applied to an differentiating circuit 15 through I/F 14 to be differentiated, and the differential result is applied to a comparing circuit 16 to be compared with a designated level applied to an input terminal 17. Thus, an output pulse string is obtained. The leading edge point of the first pulse is detected by CPU 5, and according to the detection signal, an igniter 10 is driven to ignite the engine. The leading edge point of the pulse is positioned on this side of TDC of the engine. Accordingly, even if a crank angle sensor 1 breaks down, the operation of an engine can be contiued. |
