In 1892, Rudolf Diesel invented the compression-ignition (i.e., diesel) engine. The big difference between diesel engines and gasoline engines is that gasoline engines are typically of the spark-ignition type, relying on a spark-plug to ignite the air/fuel mixture, whereas compression-ignition simply relies on physics to cause the air/fuel mixture to ignite when it is compressed to around 5% of its original volume.
Diesel engines are significantly more efficient than their gasoline-powered counterparts, and have enjoyed more popularity in most parts of the world. Unfortunately, the U.S. is not one of those parts. Although a few manufacturers have offered diesel engines in their light-duty vehicles in the past, about the only mass-market diesel vehicles you can find in the U.S. today are powered by Volkswagen’s TDI technology. It seems other manufacturers would follow VW’s lead, given the sustained success of the TDI engines.
What’s the problem here? Maybe it’s marketing: American consumers still remember the horrible diesel engines of a few decades ago, and think of them as noisy, polluting, and slow, when in fact modern diesel engines are quiet, clean, and powerful. Maybe it’s cost – diesels generally cost a tad more than their gasoline counterparts; however, diesel engines are usually built “tougher” to withstand higher compression ratios, and frequently have greater lifetimes as a result. And then there’s the efficiency benefits.
…In a past season of Top Gear, the hosts had a contest to see who could drive from Basel, Switzerland, to Blackpool in the UK, driving any car of their choice, but using only one tank of fuel. Jeremy Clarkson figured it couldn’t be done, so he chose a car that would actually be enjoyable: a Jaguar XJ6 TDVI (diesel) with a fuel economy rating of 35 mpg, and a theoretical range of 655 miles. James May chose a Subaru Legacy diesel with a rating of 50 mpg, and a theoretical range of 706 miles. Richard Hammond chose a VW Polo Bluemotion with a 3-cylinder 1.4L engine that gets 74 mpg, but equiped with only a 10-gallon tank. Before setting off, they properly adjusted their tire pressures, and (in the ultimate display of hypermiling) even sealed the body-seams with tape!
The result? Richard arrived first, followed by Jeremy, who drove like a bat out of hell with the A/C and all accessories on to demonstrate that it couldn’t be done – proving himself wrong in the process. …Captain Slow didn’t quite make it. But, it was an excellent demonstration of the efficiency of diesel vehicles. Unfortunately, none of these cars are available in the United States. What will it take to change this?