| 摘要 |
<p>Spark Duration Control for a Capacitor Discharge Ignition System An apparatus is provided for controlling ignition in an internal combustion engine having N cylinders and a capacitor discharge ignition system. The capacitor discharge system includes an ignition capacitor (18) which is maintained at a predetermined electrical potential by a charging circuit (14). N transformers (24a-f) are provided, each having a primary coil (26a-f) and a secondary coil (28a-f). The primary coils (26a-f) include first and second terminals (30a-f, 32a-f) and the secondary coils (28a-f) are electrically connected in parallel with the spark gap (22a-f) in an associated one of the cylinders. Selector switches (34a-f) are connected between the ignition capacitor (18) and an associated one of the primary first terminals (30a-f). The selector switches (34a-f) are normally biased open and are adapted to close in response to receiving cylinder select signals. The cylinder select signals are produced in response to a desired ignition sequence and for a period of time corresponding to a desired spark duration in an associated cylinder. A modulation switch (52) is connected between the primary coil second terminals (32a-f) and a source of low electrical potential. Control circuitry is provided for operating the modulation switch (52) while a selector switch (34a-f) is closed such that the current flowing in an associated primary coil (28a-f) initially rises to a first threshold sufficient to cause a spark to arc an associated spark gap. Thereafter the current is modulated between the first threshold and a second threshold lower than the first threshold to maintain the spark. The spark is maintained in this manner until the associated selector switch (34a-f) is opened.</p> |
