Why Diesel Engines Should Rule the World of Efficiency

When people talk about efficient vehicles, they usually are referring to electrics, hybrid-electrics, or ultra-compact cars.  Few in North America would think of diesels as being “efficient.”  In America, the term “diesel” has become synonymous with over-large pickup trucks and highway big rigs hauling tens of tons of freight.

The reality is, diesel is the most efficient current technology in wide use.  It’s just not widely used in the Americas.  In Europe, it rules the road.  There’s a reason for that.

While diesel fuel has more oil in it, it actually uses less oil in its production than does gasoline.  This is because it is a much simpler refinery process.  Add to that the fact that, once it’s being used in the engine, it’s much more energy dense and efficient, and you can see why diesel might be considered better than gasoline for fuels.  Never mind the potential of bio-based diesel (think “Bio Willie”) and its far simpler refinery process than corn-based ethanol.

“But,” you say, “diesel is that stuff that spews those nasty black clouds from the exhaust pipe!  We can’t have that!”  That’s where your prejudice is showing.  Even big rigs rarely spew that black smoke anymore thanks to re-burning technologies and emissions capture additions to the modern diesels of today.

Consider this further fact: a 2011 Volkswagen Jetta in gasoline gets roughly 31mpg highway and 24mpg in the city.  That same Jetta in the diesel TDI gets 42mpg highway and 30mpg in the city.  Make that diesel car a wagon and you still get 39/29 for mileage.  How’s that for a family toter?

Another problem with hybrids and electrics is price premium.  All that extra technology under the hood (and added weight) means that the car costs more.  That’s why the Chevrolet Volt, which is basically an upscale Cruz, costs about $40,000.  Even with government incentives, the car doesn’t compare to  diesel efficiency on the pocketbook, which has the same price point (or less) and is far more roomy and luxurious (given that current diesels are nearly all German models).

In fact, to further the point, a hybrid-electric or range-extended electric like the Volt would greatly benefit from replacing the gas-burner under the hood with a diesel.  Diesel engines have a sweet spot that maximizes energy output versus energy being used.  Compared to the same in gasoline cars, this sweet spot is far more efficient.  That would mean even more savings on that hybrid technology.

Now here’s a final kicker for you: guess what type of car won the Green Car of the Year Award at the Los Angeles Auto Show two years in a row?  Yep, diesels.

There are many advantages to diesel that you won’t see in the near-term with other efficiency technology.  Best of all, it’s readily available, requires little or no infrastructure change, nothing new of the driver using it, and has a far longer engine lifespan to boot.  All with little or no cost premium.