US 4,788,505 AGranted

Advance reference cylinder trigger generator

AssigneePacific Northwest Electronics

InventorBill E. Bailey

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Abstract

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, V.sub.pt, 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 V.sub.at upon receipt of the next ignition coil derived trigger pulse, V.sub.pt. Because the V.sub.pt pulses lead spark plug discharge derived pulses, the V.sub.pt pulses lead the spark plug discharge pulse associated with the V.sub.pt pulse causing the firing of the monostable multivibrator.

Claims16

Dependent claims

An advance reference cylinder trigger generator suitable for use in a cathode ray tube based internal combustion engine analyzer, said advance reference cylinder trigger generator comprising:

(a) a cylinder position counter for receiving pulses derived from the complex waveform signals created at the primary winding of the coil of an internal combustion engine when coil energy is dissipated to create a spark discharge and producing a related cylinder position count value;
(b) a cylinder count counter for receiving said pulses derived from the complex waveform signals created at the primary winding of the coil of an internal combustion engine when coil energy is dissipated to create a spark discharge and producing a related number of cylinders count value;
(c) a latch connected to said cylinder count counter for receiving and storing said number of cylinders count value;
(d) a comparator connected to said cylinder position counter and said latch for receiving and comparing said cylinder position count value to said number of cylinders count value stored by said latch and providing an enable signal when said cylinder position count value matches said number of cylinders count value;
and,
(e) a trigger pulse generator connected to said comparator for receiving said enable signal and generating a trigger pulse.

3 more elements

Dependencies are inferred from the claim text.