Search for new fuels brings us to soy oil?

"Fill 'er up with soy oil, please." You may not hear this at your favorite service station anytime soon. But in the search for alternative fuels across the United States, the soybean, used in everything from artificial bacon bits to livestock feed, is helping power some buses and tractors this spring:

* Scientists at Ohio State University are operating a campus bus with a special blend of soybean cooking oil and diesel fuel.

* Farmers in Russellville, Ky., are using a 50/50 mixture of table-grade soybean cooking oil and diesel to test-drive their tractors.

The Ohio State researchers are finding that a blend of 20 percent soy oil and 80 percent diesel works best for buses.

"Our tests show this blend gives a slightly better fuel consumption than straight diesel fuel and also produces less smoke than pure diesel," says Dr. Helmuth Engelman, an engineer at the university. "The engine seems to run smoother on the soy oil-diesel mixture than on pure diesel."

Not only did this fuel come from America's most abundant crop -- American Soybean Association (ASA) president Allan Aves says the bean is "No. 1 in terms of acres harvested" -- but the oil at Ohio State was recovered from the school's cafeterias, where it had been used for cooking French fries.

The farmers in Kentucky, meanwhile, have found that a 50/50 mixture "gave us full power under load and seemed to burn cleanest," says Kentucky Soybean Association member Richard Dickenson.

But there may be one drawback to the spread of soy oil as a motor fuel -- price.

Says Mr. Dickenson: "We paid $2 per gallon for our last bulk purchase of soy oil. That's almost double the cost of diesel fuel."

Nevertheless, he says: "Our objective is not just to have an alternate source of fuel for our tractors. We want to use a significant amount of soy oil so as to increase demand and thereby increase the price of our product."

On the other hand, the oil's great adaptability, coupled with its abundance -- soy stocks are brimming over because of the US embargo on grain sales to the Soviet Union -- could make price less of a problem.

John Shipp, a tractor dealer who has been working with the Kentucky farmers on developing soy oil fuel, says, "The thing that interested me in soy oil was that it would burn in diesel engines without any engine modification."

However, Mr. Shipp and others say more research is needed to make sure there are no harmful effects from using soy oil. In fact, the ASA already has asked the US Department of Energy to fund new research on soy fuels.

Not everyone is convinced that the soybean ought to be used as a source of motor fuel, however -- even some in the industry itself. One of these is ASA president Aves, who said in a recent interview with the Monitor here in New York that he was no entirely convinced that soybeans ought to be used extensively for fuel when the world has so much need for protein.