Engine spark timing system with knock retard and wide open throttle advance

摘要

In a spark ignition internal combustion engine with power output controlled by a throttle, a throttle switch provides a wide open throttle signal and a knock sensor provides a knock level signal. A normal spark pulse train, corrected for intake manifold vacuum, engine speed and dwell angle, is fed through a shift register which delays each spark pulse by a fixed number of counts. A pulse train generator responsive to crankshaft rotation produces a crankshaft reference angle pulse each fixed number of degrees of crankshaft rotation; and these pulses are counted by the shift register to provide a normal spark timing. First and second up-down counters are responsive to the knock detector, the first up-down counter counting up with excessive knock and being effective to delay the counting of the shift register by a period proportional to its count, the second up-down counter being responsive to the wide open throttle switch to count downward with excessive knock and insert extra pulses between the pulses of the pulse train generator in number proportional to its count to advance spark from the normal setting.