Patent ID: 7267115
Filing Date: 2007-09-11
Classification: F02P

Abstract:
1. An ignition apparatus for an internal combustion engine, comprising: an electronic control unit for outputting an ignition signal for controlling an ignition timing; an igniter for allowing and shutting off flow of a current to a primary coil of an ignition coil by means of a switching element based on the ignition signal from the electronic control unit to thereby cause a high voltage for ignition to be generated in a secondary coil of the ignition coil, taking out ions, which are produced in an ignition plug as a result of ignition, as an ion current through application of a bias voltage, converting the ion current into an ion current output signal, and outputting the ion current output signal to the electronic control unit; and a signal line for allowing both the ignition signal and the ion current output signal to be transmitted therethrough, wherein the igniter comprises: a waveform shaping circuit having an input terminal to which the signal line is connected and an electric load is also connected in parallel, for being adapted such that a voltage at the input terminal rises above a predetermined reference voltage to turn the switching element ON when the ignition signal is caused to flow through the electric load; and an ion current detecting/outputting circuit having an output terminal connected to the input terminal to output therefrom the ion current output signal obtained as a result of conversion of the ion current, for being adjusted such that the voltage at the input terminal at a time when the ion current output signal is outputted to the electronic control unit becomes lower than the reference voltage.