Sparkplug voltage probe device having a capacitance compensating function for an internal combustion engine

In a sparkplug voltage probe device which detects a voltage applied to each of sparkplugs installed in an internal combustion engine by way of corresponding cables so as to analyze a burning condition in the internal combustion engine on the basis of the voltage applied to each of the sparkplugs;

• the sparkplug voltage probe device comprising:
• an insulator base attached to the internal combustion engine, an upper surface of the insulator base having a plurality of grooves in which the corresponding cables are placed;
• an electrode plate embedded in the insulator base along the grooves to form a static capacity between the electrode plate and an array of all the cables in the grooves, the electrode plate being geometrically adjusted toward any of the cables to smooth the static capacity so as to form a capacitance adjusting means, and thereby substantially even distribution of the static capacity static capacity so as to form a capacitance adjusting means, and thereby substantially even distribution of the static capacity between the electrode plate and the array of all the cables in a direction perpendicular to a length of the electrode plate;
• and
• a lead wire provided to electrically connect the electrode plate to a microcomputer.