| 摘要 |
1,163,678. Ignition systems. ROBERT BOSCH G.m.b.H. March 22, 1968 [March 23, 1967], No. 13957/68. Heading F1B. An ignition system comprises an ignition coil 16, 18, an electronic switch 15, normally maintained in the non-conductive state, connected in series with the primary winding 16 of the ignition coil, a control device 14 for controlling the electronic switch and a contactless signal generator 13, for controlling the control device in timed relation to the rotation of the engine and thereby periodically switching on the electronic switch and switching it off again at the instant of ignition whereby current in the primary winding 16 of the ignition coil is interrupted and a high tension pulse is triggered in its secondary winding 18 for producing a spark at a sparking plug 11. The contactless signal generator and the control device are adapted to maintain the electronic switch conductive for an increasing proportion of the time interval between two successive ignition operations by advancing the instant of switching on the electronic switch relative to the instant of switching off in dependence upon engine speed at least over a part of the operating speed range of the engine. The signal generator 13 and control device may control the duration of the flow of current through the primary winding of the ignition coil in at least the lower engine speed range so that the duration is substantially constant. As shown the signal generator 13 is magnetically operable but in a modification not shown, it employs a photo-cell. Signal generators can be constructed having magnetic field dependent resistors. The ignition timing may be controlled centrifugally. |
