Volkswagen Jetta to carry clean diesel
The last Jetta TDI sold in the U.S was the 2006 model, which had a 1.9-liter four-cylinder with 100 hp that was rated at 30 mpg city, 38 highway. That’s not bad but that diesel’s technology is almost a decade old.
Starting early 2008, the Jetta will again be available with a diesel - a 2.0-liter unit that pumps out 140 horsepower and 235 lb-ft of torque – but with all new technology this time. Though it’s the same displacement as the 2.0T FSI, the engines don’t have any the same major components.
Piezo injectors are used in the new engine’s fuel injection system. It operates at up to 1800 bar - that’s a dithering 26,000 psi. The ultrahigh pressures spur the diesel atomization and combusts completely, maximizing power yet minimizing pollution, smoke, and noise. Through variable turbine geometry turbocharger that helps minimize turbo lag, air is force-fed into the cylinders.
Best of all, the Clean Diesel is 50-state legal, meeting the ultra-strict BIN5 ULEV2 standards. It makes use of a selective catalytic reduction system that is maintenance-free for 120,000 miles; furthermore, no urea injection is needed. Despite the big bump in horsepower, the new engine produces a shocking 60 percent emission less than the old 1.9-liter.
A single housing with an oxidation catalyst (to manage hydrocarbons and carbon monoxide) and a particulate trap (to lessen smoke and particulate emissions) is mounted close to the engine. A Lean NOx trap that stores oxides of nitrogen, burning them off at regular intervals while driving, is located further down the exhaust stream.
That complex exhaust after treatment soaks up most of the fuel economy benefit by about ten percent. Engineers have seen fuel economy as high as 40 mpg in city driving and 60 mpg on the highway. Though EPA numbers haven’t been released yet, Volkswagen expects the ratings on the new, more difficult 2008 EPA test, to be almost the same as the 1.9-liter’s rating.
The Jetta Clean Diesel will be available standard with a 6-speed manual transmission.
