Abstract: Engine cylinder contribution analysis is provided. An engine cylinder contribution tester includes a displacement measurement device and a signal analyzer. The displacement measurement device detects engine block movements or displacement relative to a fixed position caused by a poorly contributing cylinder. The displacement measurement device provides a displacement signal to the signal analyzer. The signal analyzer includes a cylinder contribution module for evaluating the displacement signal. If a particular cylinder is contributing less than the average of the other cylinders, the displacement signal indicates engine block movement associated with a lack of contribution from that cylinder.

Abstract: Peak capture circuitry for measuring a peak value of a waveform characterized by a first portion having a first rate of change and a second portion having a relatively faster rate of change. Peak stretching circuitry stretches a portion of the waveform as a function of time. Digital signal processing circuitry samples an output waveform of the peak stretching circuitry for determining the peak value. Thus, despite any steeply sloped portion, samples can be reliably taken throughout the waveform for calculation of peak value.

Abstract: Method and apparatus for displaying ignition coil waveforms. The method includes disposing a plurality of capacitive elements adjacent a plurality of coil-over-plug ignition coils. Signals detected by the capacitive elements are supplied to an adapter in which signal gain, polarity, and range are selected according to a particular vehicle tested, and displayed.

Abstract: Peak capture circuitry for measuring a peak value of a waveform characterized by a first portion having a first rate of change and a second portion having a relatively faster rate of change. Peak stretching circuitry stretches a portion of the waveform as a function of time. Digital signal processing circuitry samples an output waveform of the peak stretching circuitry for determining the peak value. Thus, despite any steeply sloped portion, samples can be reliably taken throughout the waveform for calculation of peak value.

Abstract: An interface for coupling an engine analyzer to an engine having a distributorless ignition system includes a pair of pickup clamps for coupling signals from respective groups of spark plug wires. A logic cell array is supplied with spark plug secondary voltage polarity and pattern information, corresponding to an engine under test from a ROM. The technician is instructed as to which wires to place in each clamp. A semiconductor input switch is controlled by the logic cell array to sort the secondary voltages from the pickup clamps according to polarity. The real and the wasted sparks are then determined based upon the magnitude of the signals from the input switch. The apparatus permits a "rapid test" (of secondary voltages only) by developing a pseudo primary clock from the pickup clamp signals. A CPU in the interface is controllable by an external computer or by an operator keypad.

Abstract: An interface for coupling an engine analyzer to an engine having a distributorless ignition system includes a pair of pickup clamps for coupling signals from respective groups of spark plug wires. A logic cell array is supplied with spark plug secondary voltage polarity and pattern information, corresponding to an engine under test from a ROM. The technician is instructed as to which wires to place in each clamp. A semiconductor input switch is controlled by the logic cell array to sort the secondary voltages from the pickup clamps according to polarity. The real and the wasted sparks are then determined based upon the magnitude of the signals from the input switch. The apparatus permits a "rapid test" (of secondary voltages only) by developing a pseudo #1 primary clock from the pickup clamp signals. A CPU in the interface is controllable by an external computer or by an operator keypad.

Abstract: A method and apparatus of developing a stabilized power firing event signal for a cylinder in a wasted spark ignition system having pairs of complementarily connected cylinders, each with a spark plug connected to an opposite end of an independent ignition coil. The first and second firing event signals are developed for each spark plug upon firing of the ignition coil. The first and second signals are combined with like polarity in a summation circuit for eliminating common mode signal portions. The combined signal, which is now stabilized and accurately indicates spark duration, is used for capturing secondary ignition data and may be visually displayed for analysis.

Abstract: A method of determining the cylinder #1 power firing event in a wasted spark ignition system comprises developing a first signal comprising the integration of all power firing event signals, a second signal comprises the integration of all wasted firing event signals and comparing the amplitudes of the two signals to determine which represents the power firing events. The firing event signals are sorted for integration based upon knowledge of the polarity of spark plug firings, the cylinder firing order and the occurrence of a #1 cylinder firing event signal.