The penguin's motorcycling and Jeep blog

Saturday, May 21, 2011

Diesels in American vehicles

If you go to Europe, you see diesel-powered vehicles everywhere. Diesel engines typically get roughly 40% better fuel economy than gasoline engines -- for example, the VW Golf gets 23/33 city/highway in gas trim, 30/42 in diesel trim.

So why aren't diesels so popular here in America? Well, let me count the ways...

  1. No market for fuel economy. Fuel is $10/gallon in Europe right now. It's "only" $4/gallon here in the USA. So people don't care about fuel economy, they get the engine that's cheapest, and a gasoline engine is generally cheaper than a diesel because it doesn't have to be built as sturdy (due to lower compression and less torque).
  2. Poor diesel fuel. Even current "low sulphur" diesel fuel here in the U.S. would be illegal to sell in Europe, because it still has enough sulphur in it to cause soot (the black smoke you used to see coming out of the back of diesel-powered vehicles). This in turn means it's extremely expensive to certify diesel vehicles here in America, because you must add filters and traps and possibly urea injection in order to deal with the poor fuel. Not to mention the number that the crappy diesel fuel sold here in America does to injectors and fuel pumps... you go by the VW TDI forums, you'll find that VW has been replacing thousands of fuel pumps because gas stations mixed gasoline in their diesel tanks and wrecked the lubricousity of the fuel, thereby depriving the pump of lubrication and causing it to self-destruct.
  3. No volume. It costs roughly $100M to certify a new engine/transmission combination if you have to do major work to it in order to . If you sell 10,000 vehicles per year over the next 5 years with a given engine/transmission combination, that means you need to charge roughly $2,000 extra apiece to pay off the EPA certification costs. And see #1.
This situation especially pisses me off because I want to see a diesel engine in the Jeep Wrangler because the extra fuel economy would make longer expeditions more feasible. Fiat has a good 2.7L dual-turbo TDI engine that would work in the Wrangler. But they only sell 90,000 Wranglers per year so, assuming that they'd sell 10,000 diesel Wranglers per year (about what they sold the last time they put a diesel into the Grand Cherokee), it just doesn't make financial sense for them to do so. It just takes too much money, time, and effort to certify an engine/transmission combo to make it worthwhile to make a Euro-diesel engine work in a U.S. vehicle.

So next thing I'm waiting for is the 3.6L Pentastar engine to make it into the Wrangler. The Pentastar makes almost 300 horsepower. It was supposed to make it into the 2011 Wrangler but didn't, probably because it turns out that it makes too much horsepower for the old transmission and they had to use a new transmission but the new transmission is three inches longer, meaning they had to relocate the engine slightly forward to make room for the new transmission, meaning they had to put slightly longer sheetmetal on the front of the Jeep to make room for the engine being further forward, meaning it required more work than just swapping a new engine into the Wrangler. But with the 3.6L Pentastar and new sheetmetal, the Wrangler ought to get better mpg than it currently does. Not that this would be difficult... my Wrangler is averaging 12mpg in the city. Something to do with the aerodynamics of a barn door and big sticky tires...

-- Badtux the Auto Geek Penguin