Patent ID: 7581534
Filing Date: 2009-09-01
Classification: F02P

Abstract:
1. An internal combustion engine ignition device including an ignition coil having a primary coil and a secondary coil and a switching element that generates an ignition high voltage across the secondary coil of the ignition coil by flowing and interrupting a primary-coil current of the ignition coil, the internal combustion engine ignition device comprising: an ECU (electronic control unit) including a pulse generation circuit that supplies a coil-driver input signal line with a single pulse signal having an extremely short duration or a plurality of pulse signals, as an energization start signal Igt a pulse detection circuit that stores the energization start signal and the de-energization signal, that recognizes the single pulse signal or the plurality of pulse signals, received by way of the coil-driver input signal line from the pulse generation circuit, as the energization start signal or the de-energization signal, and that supplies an ignition signal to the switching element; an ion bias circuit that is connected to a low-voltage side of the secondary coil and generates an ion current; an ion-current detection circuit that detects an ion current flowing through the secondary coil; an ion-current output circuit that outputs an ion signal at the coil-driver input signal line, based on an output signal of the ion-current detection circuit; and an ion-signal detection/control circuit that is included in the ECU and that detects and controls an output signal of the ion-current output circuit, wherein, at a timing when the pulse generation circuit outputs neither the energization start signal nor the de-energization signal, the ion-signal detection/control circuit sets an input voltage Igt of a coil driver to a high level, and at a timing when the pulse generation circuit outputs the energization start signal or the de-energization signal, the input voltage Igt of the coil driver is lowered for an extremely short time from the high level to a low level, so that the pulse detection circuit recognizes the change in the input voltage Igt as the energization start signal or the de-energization signal and supplies an ignition signal to the switching element, and wherein, at a timing except the timing when the energization start signal and the de-energization signal is supplied to the pulse detection circuit, the ion-current output circuit outputs an ion signal at the coil-driver input signal line, based on an ion current detected by the ion-current detection circuit.