Toward a Cleaner Car

Most of the smog that shrouds U.S. cities is belched by the internal combustion engine. The surest solution would be to ban all cars from cities —a proposal that actually passed the California state senate in July before it was killed in a house committee. Another is to build fume-free auto engines run by electricity or even nuclear power. But none of this is likely to delight Detroit automakers or the politically potent oil industry. Is there any compromise solution?

Perhaps. Taking a tip from the oilfields, where pumps are powered by natural gas, the Los Angeles-based Pacific Lighting Service Co. has applied the same principle to auto engines. After yearlong tests of six cars and trucks fueled by natural gas, the company reports a dramatic decrease in air pollution. Because natural gas burns cleanly, the vehicles emitted almost no hydrocarbons. Measuring the emissions with infra-red light, engineers found that carbon monoxide in the exhaust fell from 28 grams per mile with gasoline to 2 with natural gas; nitrous oxides dropped from 4 grams to .5. Already the company has started converting 1,100 other vehicles in its fleet to natural gas. Last month the Federal Government began testing the Pacific Lighting system for possible use on its own 51,000 vehicles.

More Mileage. In switching cars to natural gas, the big advantage is that the internal-combustion engine can be retained. The only requirement is a natural-gas mixer that fits on top of the carburetor and feeds the new fuel to the present combustion chambers. A dashboard control permits the driver to switch from natural gas in polluted areas to regular gasoline on the open road. With natural gas, the company claims, engine oil lasts up to a year, sparkplugs fire for 50,000 miles, and valve jobs are usually unnecessary. Better yet, 100 cu. ft. of natural gas gives about 15% more mileage than a gallon of gasoline and costs about 63% less.

Despite these advantages, Detroit is skeptical. Though General Motors has offered conversion units for the past year, it has sold only a few—mainly to truckers in the South, where natural gas is plentiful. For motorists, the Pacific Lighting system has not solved a key problem: the bulky gas cylinders require most of a car's trunk space. The $300 charge for converting a car to natural gas is also likely,to deter all but ardent conservationists.'Still, the prospect of greater operating economy could attract fleet owners, start mass production, and eventually lower the conversion charge. If all U.S. vehicles ran on natural gas, its advocates claim, smog could be reduced by as much as 90%.