The year-long test, which began last fall on more than 180 urban commercial vehicles from seven Southern California fleets, was initiated by ARCO on its new EC Diesel fuel and is continuing under BP Amoco, which recently acquired ARCO. The test is designed to evaluate the effectiveness of new low sulfur diesel fuels, combined with exhaust filters that trap particulates, compared to existing California-spec diesel fuel, which is considered one of the nation's cleanest.
Participants in the test demonstration study include San Diego School District buses, City of Los Angeles refuse and street maintenance trucks, Los Angeles Mass Transit buses, Santa Monica Big Blue buses, Ralph's Grocery tractor-trailer trucks, Hertz rental maintenance trucks, and BP Amoco gasoline tanker trucks.
Initial testing was done by West Virginia University's mobile laboratory. According to the study, overall emission reductions in the test vehicles averaged between 90 and 99 percent for particulate matter, hydrocarbons and carbon monoxide. Along with West Virginia's lab, UC Riverside and the California Air Resources Board will be conducting additional emission testing.
The test results are being attributed primarily to the low sulfur content of BP Amoco's new fuel that has a maximum sulfur content of 15 parts per million, and its use with catalytic exhaust filters. The sulfur content of diesel fuel used by most California fleet operators is almost 10 times greater, at an average of 120 ppm. Diesel fuel used in other parts of the country averages 340 ppm but can contain up to 500 ppm. The ultra-low sulfur content of the fuel is important because it enables the catalytic exhaust particulate traps on diesel engines to function.
"We are very pleased that the emission results are even better than we expected," said Mike Hoffman, BP Amoco's business unit leader, who runs its Los Angeles refinery. "Even though diesel fuel has been increasingly scrutinized by air quality advocates, this data shows that this new low sulfur fuel, working with particulate filters, will be similar to alternative fuels in reducing emission levels resulting in healthier air quality. Most importantly, it's available now, well in advance of anticipated regulatory requirements aimed at helping reduce emissions in Southland urban fleets."