JPS57153967A - Ignition timing controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To detect abnormality of an engine through a state of torque down or the like during its operation in an ignition timing controller used with a knock sensor, by setting a delay angle to the second amount, larger than at normal time, when th abnormality is detected with knock sensor. CONSTITUTION:A knock signal 4 passes through a timer 10 and inverter 25, and is input to an AND circuit 26 then input to a counter 37 as a clock signal. While a fail decision signal 6 is input to an OR circuit 24 with a signal, passing buffers 21, 22, further input to a LOAD terminal of the counter 37. Further the signal 6 is input to analog switches 29, 30 as a control signal, passing through resistors 35, 36 to become signals 19, 19', turned to a level H at failure while L except at the failure, and the signals are input to the counter 37. These inputs cause the counter 37 to output a higher counting value than at normal time at fail time, and a delay angle at knock sensor abnormal time is set larger than a maximum delay angle at normal time through a D/A converter circuit 38 and ignition signal generator circuit 39.