| 摘要 |
In order to vary the timing of the ignition of an air/fuel mixture in a cylinder of an internal-combustion engine as a function of engine speed, a flip-flop is set by an engine-controlled switch at a predetermined point t0 in the cycle, in a position preceding by an angle alpha 0 the upper-dead-center position of an associated piston, to effect a rapid discharge and to start a slow recharge, at constant rate, of a capacitor C1 forming part of a time/voltage converter. The maximum voltage attained by this capacitor at the end of a cycle, as a measure of cycle length T, is registered in an ancillary capacitor C3 as another capacitor C2, forming part of a voltage/time converter, also begins charging at time t0 at a rate making the charges of capacitors C2 and C3 equal on or before the attainment of the UDC position. This equality is detected by a comparator which thereupon, at a time t0+t gamma , resets the flip-flop to trigger an igniter for the associated cylinder. The charging rate of capacitor C2 may be modified by one or more sensing circuits responsive to external parameters and/or by one or more threshold circuits upon the charge of capacitor C1 or C2 reaching a predetermined level. Capacitors C2 and C3 are discharged upon the resetting of the flip-flop, the recharging of capacitor C3 beginning shortly thereafter.
|
