| 摘要 |
<p>A capacitor discharge engine ignition system includes an ignition coil having a primary winding and a secondary winding for coupling to an engine ignition spark plug. A first electronic switch has primary current conducting electrodes in circuit with an ignition charge storage capacitor and the primary winding of the ignition coil, and a control electrode responsive to trigger signals for operatively connecting the ignition charge storage capacitor to discharge through the primary winding of the ignition coil. A charge/trigger coil arrangement generates periodic signals in synchronism with operation of the engine. The charge coil generates a charge signal to charge the ignition charge storage capacitor, while the trigger coil generates a trigger signal for triggering discharge of the capacitor through the ignition coil. An electronic circuit for controlling timing of the trigger signals as a function of engine speed includes a second electronic switch in the form of an SCR having primary anode and cathode current conducting electrodes operatively connected to the control electrode ofthe first electronic switch, and a control gate electrode. An RC circuit, including a resistor and a capacitor, is operatively connected to the charge coil and the gate electrode of the SCR to prevent application of trigger signals to the control electrode of the first electronic switch during occurrence of the charge signal, and thereby control timing of application of the trigger signal to the control electrode of the first electronic switch. A third electronic switch has primary current conducting electrodes connected between the trigger coil and the control electrode of the first electronic switch, and a control electrode connected through a zener diode to the ignition charge storage capacitor. The third electronic switch prevents application of trigger signals to the control electrode of the first electronic switch at low engine speeds until the voltage stored on the ignition charge storage capacitor exceeds the zener breakdown voltage of the zener diode. <IMAGE></p> |
