Abstract: A direct current power supply applies a positive voltage between the center electrode and the ground electrode of a spark plug in an internal combustion engine after discharge of the spark plug. Ionic current flowing between the electrodes due to the positive voltage is measured by a current sensor. The ionic current caused by the positive voltage is due to electrons, so it has a large magnitude and can be easily measured.

Abstract: A test and maintenance method and apparatus for an ignition system of an internal combustion engine, such as an outboard marine engine, which includes an advanced timing schedule, a nonadvanced timing schedule, and a circuit for switching between the two schedules or disabling both schedules based upon engine operating conditions. The ignition system includes an opto-electronic time base generator which produces two sets of timing pulses relative to crankshaft position which are nonadvanced timing pulses and advanced timing pulses. The time base generator comprises two LED phototransistor pairs and an encoder disk attached to the crankshaft with slots to interrupt the radiation path between each LED-phototransistor pair. The encoder disk is provided with a synchronizing slot, multiple timing slots associated with the cylinders of the engine, and a direction slot. The test function of the apparatus verifies the timing and sequence of timing pulses.

Abstract: A timing analyzer for engine diagnostic testing includes a variable sensitivity knob for testing ignition timing for both a conventional four stroke engine and a DIS four stroke engine. The timing analyzer has a pickup which is adapted to be placed around a lead from a spark plug in the engine. During spark plug firing, a current spike appears in the spark plug lead. The timing analyzer is adapted to be triggered when a current spike above a selected threshold level is detected. When the timing analyzer is triggered, a pulse of light is produced from the nose cone of the analyzer. During engine operation, the spark plugs are continuously being fired, which creates a strobe light effect from the analyzer. The timing analyzer is aimed at timing marks on the engine block, and at a single mark on the rotating flywheel, which permit the engine to be properly timed.

Abstract: Ignition timing of an internal combustion engine of an automotive vehicle is automatically adjusted by idling the engine with a distributor whose coil terminal and spark plug terminals are disconnected from ignition circuit and detecting an spurious ignition signal for a specified cylinder from the distributor. The distributor is turned with respect to the engine through an angle in accordance with a difference between a rotated angle of the crankshaft of the engine from a detection of the spurious ignition signal to a provision of a top dead center signal and a predetermined angle of the crankshaft for an expected ignition timing.

Abstract: An apparatus for testing an i.c.e. ignition system of the kind including an ignition coil and a semi-conductor switch means controlling current interruption in the coil primary, includes a voltage comparator connected to compare the voltage across the switch means with a predetermined voltage. The comparator output starts a monostable timer circuit, the output of which is gated with the output of the comparator to produce an output signal only if the voltage across the switch means falls below the predetermined voltage within a predetermined time duration.

Abstract: A test apparatus for testing electronic ignition systems includes a circuit for detecting the interruption of ignition coil primary current and triggering a 100 .mu.S monostable. A coil current detector detects when coil current flow is recommenced and the signals from this detector and the monostable are combined via a gate to indicate satisfactory operation if the detector detects current re-commencement within 100 .mu.S of the previous current interruption.

Abstract: An apparatus and method for detecting a defective distributor is shown. The apparatus includes an input system providing the time of each cylinder firing after an initial firing of cylinder #1. A processor then determines the deviation between the actual time of firing and an optimum time thereof.

Abstract: The apparatus for testing a device controlling the ignition of an engine comprises rotary driving means for driving the device and simulating the driving of the device in normal operation; an angular encoder mechanically coupled to the driving means for providing a series of clock pulses the frequency of which is a function of the speed of rotation of the driving means; means for producing a pulse signal representing the ignition initiating signal delivered by the device when it operates in the course of its use with the internal combustion engine; at least one circuit for measuring an angular parameter of operation of the device, the measuring circuit being connected to the encoder and to the pulse signal producing means for producing a measurement signal formed by a series of measurement pulses each of which occurs respectively in the course of a revolution of the driving means, each pulse representing the angular parameter to be measured and a display device for displaying the number of clock pulses occurr