Research Projects

Project at a Glance

Title: Effects of Phase 1 and Phase 2 gasoline on evaporative and exhaust emissions from light-duty vehicles

Principal Investigator / Author(s): Dudek, Clark, Lucas

Contractor: Automotive Testing Laboratories

Contract Number: a132-183

Research Program Area: Emissions Monitoring & Control

Topic Areas: Mobile Sources & Fuels, Stationary Sources


Automotive Testing Laboratories, Inc. performed a study of evaporative and exhaust emissions generated by gasoline powered vehicles using California fuels. The four fuels used in this study were designed to represent a California pre-1992 Base gasoline, 1992 California Phase 1 gasoline. The Splash Blended Ethanol gasoline used the same hydrocarbon base as the California Phase 2 gasoline and was included to examine the effects of allowing a one psi exemption for Reid Vapor Pressure (RVP) (for the addition of ethanol as an oxygenate) which was under consideration in California at the time of the proposal. Eleven conventional vehicles covering a range of technologies (1973-1990) were tested under the then new California Test Procedure for evaporative emissions (ARB mail-out 92-10). Exhaust and evaporative emissions were analyzed. Selected tests were speciated for hydrocarbons, aldehydes, and / or alcohols. The mass emissions and toxic results were analyzed to determine the impact of the fuels on exhaust and evaporative emissions. Most of the conclusions drawn from the data produced by this study were well supported by previous studies. However, there was a statistically significant result which did not conform to the trends of previous studies that investigated the effects of fuel formulation on emissions. Both the 1996 California Phase 2 and the Splash Blended Ethanol fuels tended to produce lower exhaust NOx emissions when compared to the pre-1992 California Base and the 1992 California Phase 1 fuels. The 1996 California Phase 2 fuel exhaust NOx reductions were determined to be statistically significant.


For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893

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