| 摘要 |
PURPOSE:To detect the ignition failure of each cylinder of internal combustion engine, by detecting an oxygen concentration signal from an oxygen sensor mounted to an exhaust pipe. CONSTITUTION:An output terminal of a lead wire 9 of an oxygen sensor 1 is connected to an input terminal 14 of an ignition failure detecting circuit 10. The ignition failure detecting circuit 10 is provided with an integration amplifying circuit 11 for inputting an oxygen concentration signal from an oxygen sensor, a comparator 12 for comparing the output signal of the integration amplifying circuit 11 with a reference voltage signal previously set, and a monitor lamp 13 for an ignition failure to an operator when the comparing signal is a high level. It is acertained that the oxygen sensor 1 is brought into higher than a given temperature after starting an engine, and an opening degree of a throttle is controlled so that the number of revolutions of an engine attains a given value. In the case of, for example, 6-cylinder type internal combustion engine, if each cylinder is ignited, the voltage signal of the oxygensensor generates an output waveform shown in (A), and if an ignition failure occurs to some cylinder, it generates a cone-shaped waveform (B) at a constant timing, which results in easily finding an ignition error. |
