| 摘要 |
PURPOSE:To obtain an ion current detector which does not require a special high-voltage power source by using a capacitor charged with part of ignition energy as a power source for detecting the ion current. CONSTITUTION:The energization of a primary coil generates a high voltage of a negative polarity from the output terminal of a secondary coil in synchronization with the operation of an engine and said voltage is impressed to an ignition plug 3. One of the two electrodes of an ion plug 4 is grounded and the other is connected with the minus electrode of a DC power source 5. The output from the secondary output terminal of an ignition coil 2 explodes the gaseous mixture by the ignition plug 3 and charges a capacitor 8 via a resistor 9 and diodes 10, 11 at the same instant. The charging voltage of the capacitor 8 is clamped to a prescribed value by a constant voltage diode 12 until the specified value of several hundreds V is attained. The charging voltage of the capacitor 8 is impressed to the electrode of the ion plug 4. Electric current flows to the closed circuit of the capacitor 8, the ion plug 4 and the resistor 6 and the ion current is converted to the voltage and is outputted from an output terminal 7 when the engine is in the combustion state. |
