Abstract: The disclosure describes apparatus for determining the relative compression of the chambers of an internal combustion engine by analyzing the voltage or current waveform of the starter system during cranking. The waveform is rapidly and repetitively sampled by an analog-to-digital converter which converts the amplitude waveform into corresponding digital signals. A processor selects one of the signals having either a maximum or minimum value to represent each of the chambers. The processor automatically determines the number of chambers in the engine, determines the relative compression of the chambers and displays the result to the operator of the system.

Abstract: Various improvements in an analog oscilloscope for an automotive ignition analyzer are disclosed, including, among others, a short store circuit which enables the full amplitude of the firing line voltage to be displayed and a sweep trigger circuit which correlates engine speed and sweep length.

Abstract: A system for maintaining a diesel engine is disclosed herein. The system includes a timing light and tachometer.

Abstract: An interface for an ignition coil voltage analyzer is disclosed. The interface includes adaptive sample-and-store logic for secondary peak amplitude detection. The interface also generates timing pulses to effect and facilitate secondary voltage analysis, including frequency component analysis and time domain analysis.

Abstract: An automatic generator and regulator tester and method thereof. With the apparatus and method described herein, various performance characteristics of the generator and regulator are determined for comparison, automatically and electronically, to known, standardized performance characteristics.

Abstract: A diesel engine timing system including a pressure transducer coupled to the fuel injection line and an oscilloscope for visual display of the fuel pressure waveform. A timing light and tachometer are also responsive to the fuel line pressure.

Abstract: The disclosure describes an ignition system for an internal combustion engine fitted with a plurality of spark plugs. The engine rotates a distributor that includes a primary coil which induces voltages in a secondary coil. The secondary coil voltages are sequentially distributed to the spark plugs in order to operate the engine. The engine is provided with a source of common potential, generally referred to as chassis ground.Improved apparatus for displaying the waveform of the voltage produced by the secondary coil includes an oscilloscope having a first input and a second input. A conductive probe is positioned close to the secondary coil, and a single conductor operatively connects the probe to the first input of the oscilloscope. A second conductor operatively connects the second input of the oscilloscope to chassis ground so that the waveform of the voltage produced by the secondary coil is displayed on the oscilloscope.

Abstract: The disclosure describes an improved apparatus for testing a wheeled vehicle utilizing wheel-supporting rollers. All the wheel-supporting rollers are constrained to rotate at the same peripheral speed. Means are provided for measuring the angular acceleration or deceleration of the rollers.

Abstract: The disclosure describes apparatus for disabling selected cylinders of an internal combustion engine operated by periodic cycles of ignition signals. The apparatus prevents one or more predetermined ignition signals in each cycle from energizing engine components, such as spark plugs, which normally receive the ignition signals. In order to achieve this purpose, a clock pulse generator generates a uniform pulse in response to the receipt of each ignition signal from the engine. Three bistable flipflop circuits are used to produce output signals having states representative of the number of clock pulses received from the clock pulse generator. Gating circuitry returns the output signals to an initial state after receipt of a predetermined number of clock pulses, such as the number of cylinders in the engine being diagnosed. As the apparatus commences operation, removable setting means set the output signals to their initial state by means of a setting pulse generated by one of the ignition signals.

Abstract: In automatic diagnosis equipment for automobiles, it is essential for proper results that the datacarrier which carries the coded vehicle specifications corresponds with the vehicle to be tested. The present invention provides a system for checking correspondence between the datacarrier and the car to be tested which comprises a code-key in which the car characterizing code is recorded, said code corresponding with a code recorded on the datacarrier, and means for reading out the code on the code-key and the code on the datacarrier, for comparing them and for signaling and/or blocking the test program in the event of absence of agreement.

Abstract: The automatic output zeroing apparatus includes an energy storage device and a differential operational amplifier. The energy storage device, which is connected to one input of the differential operational amplifier, is charged to a voltage representing the free air voltage generated by the exhaust emission analyzer. The other input of the differential operational amplifier receives the pollution-indicating voltage generated by the exhaust emission analyzer. The differential operational amplifier produces a modified pollution-indicating voltage, representing the difference between the generated pollution-indicating voltage and the free air voltage.