A method to assess the spark plug fouling propensity of an engine has been developed which uses a series of high load, short duration vehicle drive cycles. The engine is force-cooled between each test, enabling a high rate of testing. It is found that fouling causes a deterioration in engine performance over the course of a series of drive cycles, due to an increasing rate of engine misfires. A software routine has been developed which can detect misfires from high resolution engine speed data taken during the drive cycles. The method has been applied to assess the fouling propensity of spark plugs with different heat ratings. It was found that the spark plugs with a higher thermal resistance were most resistant to fouling. The electrical resistance of spark plugs, measured before and after a test, has been correlated with misfire level and shown to be a poor indicator of likely performance. Resistance has been found to fall significantly during a period of 30 minutes after a drive test. This is attributed to moisture condensing onto the spark plug.
The assessment of spark plug fouling propensity through vehicle drive cycle tests
Bewertung der Neigung zur Zündkerzenverschmutzung durch Fahrprüfzyklen
1993
8 Seiten, 9 Bilder, 3 Quellen
Aufsatz (Konferenz)
Englisch
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