Importance

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Abstract

An ignition adapter for DIS four stroke engines provides conventional voltage waveforms for a diagnostic oscilloscope. Spark plug leads from a DIS four stroke engine are grouped together depending on their respective firing polarity. A first signal pickup is placed around the spark plug leads from the spark plugs of one signal polarity, for example a positive signal polarity, and a second signal pickup is placed around the spark plug leads from the spark plugs of opposite polarity, for example a negative signal polarity. A trigger pickup is placed around the #1 cylinder spark plug lead. The voltage waveforms received in the signal pickups are applied to the ignition adapter, summed and displayed on the oscilloscope as a conventional voltage waveform. The polarity of the waveform can be reversed using a polarity switch. The waveform received in the trigger pickup is applied to the ignition adapter and compared to a reference voltage. When the waveform exceeds the reference voltage, a voltage pulse is applied to the oscilloscope as a trigger pulse. The ignition adapter includes a trigger adjust that can be set to trigger the oscilloscope on the higher voltage levels present during the compression stroke of the DIS four stroke engine, thereby to emulate a conventional voltage waveform.

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First Claim