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Title: Diesel engines vs. spark ignition gasoline engines -- Which is ``greener``?

Criteria emissions, i.e., NO{sub x}, PM, CO, CO{sub 2}, and H{sub 2}, from recently manufactured automobiles, compared on the basis of what actually comes out of the engines, the diesel engine is greener than spark ignition gasoline engines and this advantage for the diesel engine increases with time. SI gasoline engines tend to get out of tune more than diesel engines and 3-way catalytic converters and oxygen sensors degrade with use. Highway measurements of NO{sub 2}, H{sub 2}, and CO revealed that for each model year, 10% of the vehicles produce 50% of the emissions and older model years emit more than recent model year vehicles. Since 1974, cars with SI gasoline engines have uncontrolled emission until the 3-way catalytic converter reaches operating temperature, which occurs after roughly 7 miles of driving. Honda reports a system to be introduced in 1998 that will alleviate this cold start problem by storing the emissions then sending them through the catalytic converter after it reaches operating temperature. Acceleration enrichment, wherein considerable excess fuel is introduced to keep temperatures down of SI gasoline engine in-cylinder components and catalytic converters so these parts meet warranty, results in 2,500 times more CO and 40 times moremore » H{sub 2} being emitted. One cannot kill oneself, accidentally or otherwise, with CO from a diesel engine vehicle in a confined space. There are 2,850 deaths per year attributable to CO from SI gasoline engine cars. Diesel fuel has advantages compared with gasoline. Refinery emissions are lower as catalytic cracking isn`t necessary. The low volatility of diesel fuel results in a much lower probability of fires. Emissions could be improved by further reducing sulfur and aromatics and/or fuel additives. Reformulated fuel has become the term covering reducing the fuels contribution to emissions. Further PM reduction should be anticipated with reformulated diesel and gasoline fuels.« less
Authors:
 [1]
  1. Dept. of Energy, Washington, DC (United States)
Publication Date:
OSTI Identifier:
334053
Report Number(s):
CONF-970799--PROC.
ON: DE99000798; TRN: IM9917%%17
Resource Type:
Conference
Resource Relation:
Conference: 1997 diesel engine emissions reduction workshop, San Diego, CA (United States), 27-31 Jul 1997; Other Information: PBD: [1997]; Related Information: Is Part Of Proceedings of the 1997 diesel engine emissions reduction workshop; PB: 488 p.
Research Org:
Dept. of Energy Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Transportation Technologies, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; 33 ADVANCED PROPULSION SYSTEMS; DIESEL ENGINES; SPARK IGNITION ENGINES; ENVIRONMENTAL IMPACTS; COMPARATIVE EVALUATIONS; AIR POLLUTION; CATALYTIC CONVERTERS; PERFORMANCE; DIESEL FUELS; GASOLINE