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Paper Number: 2012-01-1151
Published: April 2012
Authors & Affiliations:
Timothy J. Jacobs
Texas A&M University
Louis J. Camilli, Joseph E. Gonnella
A key element to achieving vehicle emission certification for most light-duty vehicles using spark-ignition engine technology is prompt catalyst warming. Emission mitigation largely does not occur while the catalyst is below its “light-off temperature”, which takes a certain time to achieve when the engine starts from a cold condition. If the catalyst takes too long to light-off, the vehicle could fail its emission certification; it is necessary to minimize the catalyst warm up period to mitigate emissions as quickly as possible. This study examined how pulsed energy spark plugs using an embedded capacitor directly to the center electrode, to produce a 5MW electrical discharge that conditions the fuel charge at the molecular level during the spark event. This discharge forms a plasma field with very high ultraviolet photon energy around the spark gap. The plasma field extends into the combustion chamber and sensitizes a large portion of the fuel air mixture, thus greatly enhancing combustion during cold start. This allows a vehicle to reach the light-off temperature level more quickly while reducing unburned hydrocarbon emissions.