Abstract: The present invention is a metering system including a signal conditioning circuit, processor and output system. The signal conditioning circuit receives a state-indicating signal and responsively produces a repetitive digital signal compatible with the processor. The processor samples the repetitive digital signal, determines the period thereof and produces an output signal having a value related to the state-indicating signal. The output system displays the value of the output signal.

Abstract: The disclosure describes an improved automated engine diagnosing device employing a digital data processor computer and a cathode ray tube display monitor which displays engine parameter (i.e., condition) values in alphabetic, numeric, and graphical form. Some data is accumulated from the engine by means of direct digital measurements, whereas other data is obtained from the engine by an analog-to-digital converter. The data is then processed by the computer and displayed on the cathode ray tube display monitor.

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.