For many people, the thought of a diesel engine brings to mind some old, outdated stereotypes. Diesel
engines aren’t just for jacked up 4×4’s with huge tires that blow black smoke and massive construction
equipment that make as much noise as a jet. Those images have about as much to do with the diesel
engine’s efficiency as an abacus does with a laptop computer. Advances in diesel engine efficiency have
brought it a long way. In fact, they’re more fuel efficient than their gasoline counterparts. In the same
car, a diesel engine will get more miles per gallon than a gasoline one.
Historically, the diesel engine hasn’t run the cleanest. There was a time when this engine would pour
black smoke down the highway. Fortunately, advancements in technology have made that a thing of the
past. Wayne Killon, the general manager of product strategy and launch for Audi of America, said that,
“Technology like selective catalyst reduction, SCR for short eliminates harmful byproducts like oxides of
nitrogen. In this system a urea solution is injected into the exhaust stream where it reacts in a special
catalyst, breaking up dangerous NOx into harmless nitrogen and oxygen.”
Diesel fuel is made with a hydrocarbon mix that’s produced by distilling crude oil, and this makes diesel
fuel denser than gasoline. It has a higher boiling point than water as well, which gives it a lower
evaporation point than gas; regular gas will evaporate at room temperature. Gasoline is classified as
“flammable”, which means that all it needs to burn is a spark. Diesel is classified as combustible,
meaning that it needs both heat and compression to function. One gallon of diesel produces 22,000
BTUs more than one gallon of gasoline, as a result.
Diesel fuel is more efficient because it is thicker than gas, which means it is more energy dense. The
combustion of diesel emits less carbon monoxide and dioxide than gas, as well. Improvements in the
refining process and advances in engineering has created more power within the diesel engine. Less fuel
is needed to create the power, which means less fuel is burned—the diesel engine is more energy and
fuel efficient than it’s gasoline counterparts
