Cleaner-Burning Gasoline Performs Well in Vehicles, Equipment, State/Industry Panel Concludes
A panel of technical experts from the California Air Resources Board (ARB) and the oil and automotive industries has concluded that the cleaner-burning gasoline to be introduced in California in 1996 performs as well as current gasoline in motor vehicles and motorized equipment.
"The manufacturers of motor vehicles and gasoline agree with us that California's cleaner-burning gasoline will significantly reduce air pollution while enabling motor vehicles and other equipment to perform at the high level that Californians expect," ARB Chairman John D. Dunlap said.
"Cleaner-burning gasoline has been thoroughly tested and has broad-based support within industry," Dunlap said. By June 1996, all gasoline sold in California must meet ARB's cleaner-burning requirements. Cleaner-burning gasoline, known officially as California Reformulated Gasoline, will reduce smog-forming emissions from motor vehicles by 15 percent and human exposure to gasoline-based toxics by 30 to 40 percent.
Representatives of gasoline refiners, vehicle manufacturers, service station dealers, vehicle fleets and other industries and government agencies served on an advisory panel that helped oversee a six-month ARB test program to evaluate the performance of cleaner-burning gasoline. The panel evaluated the results of both the ARB test program and tests conducted by private companies.
The ARB on-road test program involved 829 vehicles in eight private and government fleets that drove about 5 million miles on cleaner-burning gasoline between February and August 1995. An additional 637 vehicles used commercially available gasoline and served as a control fleet. Chevron, Texaco, General Motors, Ford, Nissan and Harley-Davidson conducted their own tests of cleaner-burning gasoline.
The advisory panel's findings on the on-road tests include:
- In the ARB test program, cleaner-burning gasoline performed as well as conventional gasoline in terms of driveability, starting, idling, acceleration, power and safety.
- There was no meaningful difference between the frequency of fuel-system problems in vehicles using cleaner-burning gasoline and pre-1996 (conventional) gasoline. About 3 percent of the vehicles in both the test and control fleets experienced problems with fuel pumps, carburetors, fuel hoses and other components.
- The frequency of problems in the test and control vehicles was well within the expected frequency based on historical maintenance and repair data for the fleets in 1993 and 1994. Newer (1991 and later) vehicles in the test and control fleets did not experience any fuel-system problems. The small number of problems occurred in pre-1991 vehicles, generally with high mileages. The average model year of vehicles experiencing problems was 1986, and the average odometer reading was 95,000 miles (with a range of 24,000 to 202,000 miles).
- Average gas mileage from use of cleaner-burning gasoline was 1 percent less than from oxygenated gasoline currently used statewide, and 3 percent less than non-oxygenated gas available in northern and central California as late as October 1995. Because oxygenated fuel is now widespread in the state, the average expected change in gas mileage with cleaner-burning gasoline is 1 percent.
- Laboratory tests by Ford and a preliminary test by General Motors found that cleaner-burning gasoline should not affect fuel-system performance. The Nissan test data showed no adverse formation of deposits from the use of cleaner-burning gasoline. And the Harley-Davidson test program found that the gasoline caused no fuel-system problems in on-road motorcycles.
- The results of Chevron's test program are consistent with the ARB's and other test programs. Chevron used a cleaner-burning gas formulation in a 115-vehicle fleet containing a significantly greater percentage of older, high-mileage vehicles than the ARB fleets. An additional 115 control vehicles used conventional gasoline. Six Chevron test vehicles experienced fuel-system problems (compared to one control vehicle). However, the frequency of problems is consistent with the historical maintenance and repair data from the ARB fleets. When the data from the Chevron fleets is combined with the ARB results, it does not change the finding that the cleaner-burning gasoline performed as well as conventional fuel.
- Texaco found that very low aromatic fuels might accelerate the failure of some fuel-system components in high-mileage vehicles. The Texaco test fuels were unusual formulations that are not intended for sale to the public. A follow-up ARB analysis found that, even if such a fuel were put on the market, its effects would be lessened by commingling in the distribution system and dilution in the vehicle tank. In addition to the on-road vehicle tests, two state agencies and various private companies tested cleaner-burning gasoline in construction and industrial equipment, farm equipment, lawn and garden equipment, boats, snowmobiles and all-terrain vehicles. The advisory panel reviewed the test results and found that cleaner-burning gasoline should not affect off-road vehicles and motorized eqiuipment. No problems attributable to the gasoline were found in test equipment. Results of some off-road tests are still pending.