LOS ANGELES (AP) _ A new chemical process that might reduce smog and acid rain from vehicle and power plant pollutants drew cautious praise from federal energy and environmental officials and an automobile industry spokesman.

''This invention has exciting potential for both pollution control and the greater use of cleaner, efficient diesel engines in industry and on the road,'' U.S. Energy Secretary John S. Herrington said from Washington.

The process, which uses an acid often added to swimming pools to extend the activity of chlorine disinfectant, was reported today in the British journal Nature by chemist Robert A. Perry and engineer Dennis Siebers, of Sandia National Laboratories' Combustion Research Facility in Livermore.

In a laboratory test, Perry and Siebers fed exhaust from a diesel engine over cyanuric acid, and found they could remove more than 90 percent of the nitrogen oxides in the exhaust.

Perry said he hopes his invention will reduce smog and contribute toward solving the acid rain problem. Nitrogen oxides react in air to help form photochemical smog and the nitric acid component in acid rain.

It will take five years to incorporate the process into practical devices to cut nitrogen oxide emissions from diesel and non-diesel motor vehicles, electric power plants and factories that make plastics, solvents and explosives, Perry said.

Harry Weaver, environmental affairs director for the Motor Vehicles Manufacturers Association, said in a telephone interview from Detroit that it is not certain motorists would accept the new method, which would involve periodically adding cyanuric acid to their cars.

Nevertheless, Weaver said he has ''the highest respect'' for Perry and Siebers, and ''if they say they've got something, it certainly deserves a thorough evaluation.''

''It's been very hard to find ways to control nitrogen oxide emissions from diesels'' because they can't use the catalytic converters that cut nitrogen oxide emissions from all non-diesel U.S. cars by roughly half, said Jeff Alson, assistant to the director of the Environmental Protection Agency's emission control technology division.

''This would be a breakthrough if it provided a relatively inexpensive way to do that,'' Alson said Wednesday from Ann Arbor, Mich.

Alson and Weaver said it must be demonstrated that Perry's process doesn't produce other harmful pollutants or hinder vehicle performance, an assessment echoed by John R. Holmes, research director for California's Air Resources Board.

Perry said the process should boost engine performance and cost about the same as catalytic converters, and won't produce other pollutants except for an acceptably small increase in carbon monoxide.

''We're sufficiently interested that we'd like to learn a lot more about it ... and perhaps provide some funding to explore this further,'' Holmes said.

The new process is most likely to be used on coal-fired power plants because the sulfur in coal neutralizes another pollution control technique being tested on natural gas- and oil-fired power plants, Perry said.

As soon as he can raise about $1 million in venture capital, he plans to quit Sandia and form a private company to develop his invention into practical anti-pollution devices. Sandia doesn't conduct applied research, so the Energy Department waived its title to his invention while retaining the right to use it without paying license fees.

AT&T Technologies Inc. operates Sandia National Laboratories under contract to the Energy Department.