| 摘要 |
An advance reference cylinder trigger generator that provides a more effective trigger signal to synchronize the horizontal sweep of a cathode ray tube based instrument used for troubleshooting, diagnosing and servicing of spark ignition internal combustion engines. The trigger pulses, Vpt, derived from the primary winding of an ignition coil are applied to a cylinder position counter (5) and, after being delayed by a delay circuit (4), to a cylinder count counter (8). When the value of cylinder position counter (5) equals or exceeds the value of cylinder count counter (8), an output from comparator (6) enables a monostable multivibrator (10) to produce an advance reference cylinder trigger Vat upon receipt of the next ignition coil derived trigger pulse, Vpt. Because the Vpt pulses lead spark plug discharge derived pulses, the Vpt pulses lead the spark plug discharge pulse associated with the Vpt pulse causing the firing of the monostable multivibrator.
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