WHY THE DIESEL It is 81 years since Rudolph Diesel first patented the engine which bears his name-the DIESEL. His first engine used coal dust blown into the combustion chamber. It was extremely temperamental, and later experiments with other hydrocarbons, particularly diesel oil, were much more successful. The result was the birth, in 1893, of the first true "DIESEL ENGINE" in the sense we know it today. Why-after all these years-the renewed interest in an engine that has been built by the millions to power trucks, locomotives, zeppelins, and many stationary installations. The answer is that the peoples of the world have finally and collectively realized the urgent need for preservation and conservation of natural resources. Business Week quotes the State Department's Office of Fuels and Energy as expecting the average price of Middle East crude (oil) to jump from about $2.25 a barrel today to $5.00 by 1980. Oilmen are forecasting gasoline price hikes of 25-50% in the next 3 years alone. A price of $1.00 per gallon is on the horizon. That puts Detroit in a two way vise. While new gadgets are lowering pollution, they are also raising gas consumption. The pollution-tuned 1973 models gulp as much as 15% more gas than 1972 cars. By 1976 the penalty may be as high as 30%. Business Week further states that the National Research Council (a 14-man ad hoc committee of the National Academy of Sciences) believes the standard piston engine will continue to power cars into the 1980s along with Wankels and diesels. The N.R.C. has high hopes for the diesel. However foul its exhaust, this pressure ignited version of the reciprocating engine is a relatively mild polluter. Motor Trend magazine says that in the smog conscious Los Angeles area they are beginning to call the diesel "the ecology car." Motor Trend further says "intriguing is the fact that low emissions characteristics are inherent in the basic design of the diesel engine; no external add-ons-such as air pumps or thermal reactors-are necessary." The diesel-powered vehicle is showing promise as a contender in the national search for a "clean air" car. Preliminary tests conducted at Southwest Research Institute for the Environmental Protection Agency indicate that polluting emissions from a diesel engine can be substantially lower than from a conventional gasoline engine. Karl J. Springer, manager of the Emissions Research Laboratory of the Institute, reported results of a test comparing the emissions from two cars, one powered by a four-cylinder diesel engine and the other by a four-cylinder gasoline engine. "Results showed that the diesel-powered car produced noticeable levels of smoke and odor under certain driving conditions," Springer said. "But, when the emission of harmful substances was checked, the diesel released only about 30 per cent as much hydrocarbons, only 5 per cent as much carbon monoxide and only 50 per cent as much oxides of nitrogen as the conventional gasoline engine." The diesel-powered car emitted less carbon monoxide than the 1975-1976 federal standards specify, though it fell short of meeting the limits for hydrocarbons and oxides of nitrogen. Cleanliness is not such a difficult problem for diesels, suprisingly. Sure, a badly out-of-tune city bus stinks and smokes, but even its exhaust can be breathed without fatal results. Since there is an excess of air in the cylinder of a well-tuned diesel when the fuel is injected and combustion begins, only the smallest traces of CO exist in its exhaust, even smoke-laden exhaust. And a diesel kept in proper shape, an easier task than keeping gas engines tuned, by the way, need not smoke at all. Before ignition takes place in a diesel, the combustion chamber is almost twice as hot as that of a gas engine, so more of the hydrocarbons are consumed in the diesel combustion process. Oxides of nitrogen, the main element in photo-chemical smog, are a problem in diesels as well as in gas engines, but if a "pre-combustion chamber" is included in the head design, the problem is much reduced. It probably can be eliminated, and most efforts now are being directed toward turbocharging as a means to clean exhausts. First of all, diesel engines are the most efficient source of power for vehicles available today. They obtain more power from a gallon of fuel than any other engine type, and the fuel they use contains more energy (BTUs) per gallon than any other readily available fuel. There are reasons why most of this country's truck and train fleets are diesel-powered, and most of those reasons are economic. Diesels are cheaper to use than other kinds of engines. Take fuel costs as an example. A typical truck that does 100,000 miles per year will use about 25,000 gallons of gasoline. A comparable diesel will use about 16,666 gallons of cheaper fuel, and will require about half as much maintenance in the bargain. The main reason these diesels were developed is their excellent economy-particularly in the part-load range. Their economy is mainly due to higher air/fuel ratios, higher compression ratios, and lower intake pumping during part-load operation. A diesel, by the way, will run on a wide range of fuels, including gasoline (provided oil is mixed with it to provide injector lubrication), while a gasoline engine is so touchy that an 80-octane engine can be put out of commission by a few tanks of 100-octane fuel. And a 100-octane engine can die a horrible death if fed 80-octane fuel. But would their noise levels and odor emissions be acceptable to the American consumers? Perhaps. The odor problem reportedly has been almost eliminated. Noise from diesel engines comes in three categories: 1. 2. The roar of the fresh air entering the engine. Efficient filter design has overcome this problem. Noise from the exhaust system. Properly designed mufflers have done away with this. 3. Typical "diesel knock" which stems from the rapid pressure rise in the cylinders. The use of swirl chambers has minimized the knock so that it remains a problem only at idle. Under load, the knock is subdued. Even at idle, the noise levels are no higher than in a VW engine at idle. There are now 3 million VWs in the U.S., indicating those levels must be acceptable to large numbers of Americans. Diesels do not have electrical ignition systems, so, one saves the weight and complexity of the magnetos, spark plugs and the attendant wiring. Since diesels are all fuel-injected, there is no intake icing problem to worry about. And the safety aspects of diesels are excellent. Diesel fuel just does not burn very quickly in open air, and its vapors are not terribly explosive in closed spaces, provided they are not pressurized. Post-crash fires are hideous dangers with gasoline vehicles, and anything that can reduce their likelihood is vitally important. Peugeot installed its first diesel engine in a passenger car in 1923. We have built over 370,000 diesel engines of the type now being used during the past 11 years. Peugeot diesel equipped passenger cars are currently sold not only in our home country, France, but also throughout Europe, Asia, Africa, and South America, where they have gained a reputation for economy, reliability, and durability. |