In Europe, diesels are a common site; they represent more than half of all new vehicles being sold there. They do not come as just small economy cars, but also upscale rides like the BMW 7-series, Jaguar S-TYPE, and Alfa Romeo 156.   Yet in America, the diesel choices are very limited to diesel pickups or passenger vehicles like the Mercedes-Benz E320 BLUETEC, VW Touareg TDI, and Jeep Grand Cherokee CDI.  With the growing concern for fuel economy, this is likely to change in the next few years, as diesels are on the rise in the USA.

A gasoline engine runs on the Otto cycle,  a vaporized mixture of gasoline and air is delivered to the combustion chamber, where it’s then compressed and ignited by a spark plug. In the Diesel cycle, air is compressed during the compression stroke and fuel is injected into hot, compressed air in the cylinder, spontaneously igniting the fuel; a compression ignition engine as opposed to a spark ignition engine.
Diesel fuel requires less refining than gasoline and is similar to kerosene, jet fuel, and heating oil. Diesel fuel is heavier, oilier, and evaporates much more slowly than gasoline.  A diesel engine gets more miles-per-gallon than an equivalent gasoline engine. This may be one reason they are common in Europe; fuel economy had always been a concern there, as high gas prices are nothing new (up to $6/ gallon).  Diesel engines are also more efficient because more power is produced as a result of the higher compression of the air/fuel mixture. Today’s gasoline engines have compression ratios of about 10:1 to 11:1, while the compression ratios in diesels can be as high as 25:1.  Although they are larger and heavier, and more expensive to build, they have a much longer lifetime then gasoline vehicles.

Rudolf Diesel obtained a German patent for the Diesel Cycle engine in 1892. Although Diesel invented the diesel engine, an American named Clessie L. Cummins can be credited with developing, and marketing the diesel for highway use in the U.S. in the early 1930s.   Mercedes-Benz offered the first diesel-powered production car, the Type 260D, in 1936, and usually has had at least one diesel car in its production year ever since.  In the 70s and 80s there was an increase in interest in America, as diesel cars from VW, Isuzu, and Peugeot were also available.  When GM joined the ranks an Oldsmobile-built diesel was offered between ’78 and ’85.  But the model had extensive problems, as the higher combustion force caused cracked cylinder blocks, blown heads, and wear on crankshafts.  From that point, there was a quick downturn in diesel vehicles in the States. Environmental concerns have also impacted America’s image of diesels. Many Americans envision diesels as highly polluting, black smoke emitting transportation. Yet what many do not know is that computerized, turbocharged diesel engines equipped with emission control devices have taken care of this pollution problem.  A modern diesel would only produce this smoke if there was a maintenance problem.  Unlike gasoline, diesel engine have to contend with significant amounts of particulate matter(soot), but carbon dioxide emissions (which are related to fuel consumption) are far less in a diesel,  making it better when it comes to this greenhouse gas.

Diesels have a promising future in this country.  Once they get over the stigma of heavy polluters, and people can see them for what they really are, highly fuel efficient  vehicles, their popularity will soar.