Methanol engines -- possible new entry in the high-mileage race
Automotive engineer Dick Passamaneck has worked on racing engines for Dan Gurney and other race car drivers. Now, working at the Solar Energy Research Institute (SERI), he is involved in a race of another sort. The object is to come up with a practical automobile engine that will be safe, efficient, and fueled by something other than petroleum.
He and his colleagues are in the middle of fitting a prototype engine, which they feel will do all these things, into a Chevrolet Citation. They expect to have it running this May.
Sitting in pieces in the engine well, the power plant doesn't look at all radical. In fact, the modifications are relatively small, but significant. The engine is still mostly a standard General Motors model. But the compression ratio has been increased to 14 to 1 and the carburetor is gone. In its place is a series of mysterious-looking cylinders nested around the engine.
These, Mr. Passamaneck explains, allow the car to use methanol rather than gasoline. Methanol can be made from wood and crop refuse or coal. Volkswagen, among other auto manufacturers, has designed cars that run on pure methanol. But methanol has one major drawback. The amount of chemical energy it contains per gallon is half that of gasoline. Estimates of the cost of mass-producing methanol put it at about 70 percent more than that of refining gasoline. so, to make it economical, a methanol-burning engine must be substantially more efficient than a gasoline engine.
The SERI engineers have attacked this efficiency question in a unique fashion. Instead of burning methanol directly, they boil it into a vapor and then use heat from the exhaust to convert it into a gas consisting of hydrogen and carbon monoxide.
"This gas has 20 percent more energy than the methanol it was made from. In the reactor [a cylinder three feet long and nine inches in diameter] some of the energy in the exhaust is converted into chemical energy in the gas," Passamaneck explains.
Ford Motor Company fuel specialist Serge Gratch says the Passamaneck system "is an extremely interesting concept. Sooner or later we will try an experiment along similar lines. Of course, it has yet to prove itself under real conditions."
A caravan of alcohol and gasohol-powered Fords currently is making a cross-country tour. But the methanol-fueled Ford engine is only slightly more efficient than a gasoline motor.
Passamaneck's hydrogen-carbon monoxide gas has a number of advantages over both gasoline and straight hydrogen, a fuel that has generated considerable research interest in the past few years. The mixture can be burned at a high compression, which increases efficiency. In low power conditions, it can be run one-third leaner than gasoline, decreasing fuel consumption substantially.
Furthermore, the carbon monoxide counteracts hydrogen's tendency to ignite prematurely. Creating hydrogen catalytically just before it is burned takes care of the hydrogen storage problem that has perplexed proponents of hydrogen as a fuel. Other methods for storing hydrogen, which, when heated by the exhaust, would release hydrogen gas.
The engine has just completed a series of stringent dynamometer tests in which it averaged 50 percent more efficiency than a conventional gasoline engine.
"We think we can get this up to 100 percent," says Passamaneck. If this goal is achieved, the engine would get the same mileage per gallon of methanol as a normal engine gets per gallon of gasoline. Thus a methanol-fueled car would be substantially less expensive to run.
On the basis of these tests, Passamaneck also expects the engine to have power equivalent to or better than a normal gasoline engine. For starting and periods of high power, the engineers are installing injectors to inject methanol directly into the cylinders. Also, turbocharging increases the engine's performance more dramatically than it does with gasoline engines, he reports.
Japanese car companies, among others, are working on similar engine designs. But "none of them have put a car on the road yet: We hope to be the first," says the auto engineer.
The engine's emissions have not yet been measured but Passamaneck does not expect this to be a major problem. The only difficulty might be with nitrogen oxides, he maintains.
The engine's cost remains a crucial question. The catalyst is made of inexpensive copper and zinc, compared with the platinum in the catalytic converters currently used to clean auto exhaust. The rest of the parts required , primarily a series of heat-exchangers, are relatively commonplace and inexpensive. Nonetheless, a detailed engineering study must be carried out before costs can be compared with those of a standard engine.
Even if it turns out to be slightly more expensive, the SERI researchers say they believe that, in return, such a car would be substantially safer than today's autos. Methanol vaporizes and dissipates faster than gasoline and burns cooler, Passamaneck points out.* Since 1964, when two drivers were killed in a flaming crash, cars racing at the Indianapolis Speedway have run on methanol because of the greater safety, he adds.