Patent ID: 9127638
Filing Date: 2015-09-08
Classification: F02P

Abstract:
1. A control apparatus for an ignition system of an internal combustion engine, wherein the ignition system includes a spark coil having a primary coil and a secondary coil being electro-magnetically connected to the primary coil, and a spark plug that produces discharge sparks in between its center electrode and its ground electrode by applying a high voltage across both electrodes on the basis of the magnetic energy stored in the spark coil, comprising: one of two ends of the secondary coil is connected to a member having a standard electric potential of the control apparatus via a low-voltage side path, and another end of the secondary coil is connected to the center electrode via a connecting path; one of two ends of a constant-voltage path is connected to the connecting path while another end of the constant-voltage path is grounded, or both ends of the constant-voltage path is connected to a secondary coil; the constant-voltage path includes a constant-voltage element, wherein the constant-voltage element, in an occasion where current is supplied to the primary coil, allows current to flow through the constant-voltage path in a specified direction that permits the polarity of the inductive voltage generated in the secondary coil to turn from negative to positive, and, in an occasion where current supplied to the primary coil is cut off and the voltage applied across the terminals of the element becomes equal to or higher than a specified voltage, allows current to flow through the constant-voltage path in a direction opposite to the specified direction and decreases voltage corresponds to the level of the specified voltage, and further includes a current detecting means which detects a current passing through the constant-voltage path; and the control apparatus includes a deterioration judging means that determines deterioration as being caused in the spark plug on the basis of the fact that a period in which the current is detected by the current detecting means has become longer than a predetermined standard period.