Abstract: An engine analyzer, for analyzing ignition voltage or current signals in an engine of the kind in which each spark plug is fed with a succession of pulses, alternate pulses producing real sparks to ignite the petrol/air mixture, the other pulses producing wasted sparks at a point of the engine operating cycle remote from ignition, the analyzer including circuitry to pass the real spark pulse and inhibit passage of the wasted spark pulses.

Abstract: A testing device is disclosed for testing structural parts and functions of motor vehicles according to a test program having successive program stages. The testing device comprises a program switch for establishing circuit connections associated with the stages of the test program and for controlling a first indicator device for reproduction of the corresponding measurements. The program switch of the device further controls a second indicator device for reproduction of stored, rated measurements associated with the program stages so that a direct comparison of the rated and actual measurements can be quickly made.

Abstract: An ignition circuit tester including a pick-up coil assembly for inductive coupling with and location closely along a circuit element to be tested, an amplifier circuit for amplifying a signal picked up by the coil assembly, and a meter to indicate the signal.

Abstract: The spark voltage waveform at the secondary of the ignition coil of an internal combustion (IC) engine is sensed over a plurality of successive engine cycles. The instantaneous sub-cyclic position of the engine crankshaft is measured at successive crankshaft angle increments within each engine cycle and each sensed spark voltage signal is identified by the instantaneous value of crankshaft position at which it appears, thereby providing identification of each spark voltage signal with an associated cylinder of the engine. The number of samples for each cylinder together with the peak KV voltage magnitude and time duration of each are measured and the maximum, minimum and mean values of peak KV and spark duration for the spark signals associated with each cylinder together with the number of samples obtained are compared with the values obtained for each other cylinder to provide an indication of the relative sub-cyclic ignition efficiency of the ignition secondary circuit and the individual cylinders.

Abstract: To permit tests of: ignition timing; dwell angle; engine speed; and voltage levels, a pulse train is provided derived from the ignition system of the engine; the pulse train is applied to a frequency multiplier, preferably a phase locked loop (PLL) which provides a sequence of output pulses having a pulse repetition rate which is a multiple of the frequency of the signals or pulses of the pulse train. An AND gate has the multiplied signals applied thereto and is enabled, selectively, in accordance with the desired test. The output of the AND gate is applied to a counter which counts multiplied pulses within the interval of enabling of the AND gate, the output being applied to a digital indicator to provide a direct readable digital output; preferably, the multiplication rate is selected to provide a digital output indication which is directly readable in desired units.

Abstract: Equipment for diagnosis of internal combustion, carburetor type engines, comprising a meter, a probe introduced in the engine 1-st cylinder high voltage circuit, a stroboscope complete with trigger, as well as resistors, rheostats and capacitors connected to a change-over switch to select the desired type of duty, which with the selector switch in specific operating position, make the circuits for checking various operating variable parameters of the engine under the test.