VW Readies Improved Diesel for U.S. Market

Later this year Volkswagen AG will begin replacing its popular 2.0-liter 4-cylinder "clean diesel" engine option in the U.S. with a more powerful and fuel efficient version with the same displacement.

The engine, dubbed EA288, shares only the same bore spacing with the outgoing oil burner, according to the company. The revised powerplant hikes power output 10 hp to 150 hp. Torque is unchanged at 236 lb-ft.

VW currently offers 12 diesel-powered passenger vehicles in the U.S. They accounted for 24% of the company's sales in 2013 and about 80% of last year's entire American diesel car market. Last year VW topped 100,000 diesel sales in the U.S. for the first time.

The EA288 will be available this autumn in 2015 model Beetle, Golf, Jetta and Passat models. The engine also will begin to replace the current 2.0-liter oil burner option in Audi models.

The outgoing diesel is about 30% more fuel efficient than a gasoline engine of comparable power with a U.S. combined city/highway fuel economy rating of about 42 mpg. VW promises an unspecified improvement over those numbers with the EA288.

Design changes for the new engine include a modular lower-pressure exhaust gas recirculation system, intercooler integrated into the intake manifold, exhaust aftertreatment system relocated closer to the engine, low-friction camshaft and balance shaft bearings, lower-friction piston rings and a two-stage oil pump.

VW says the improvements reduce internal engine friction by about 15% and cut engine-out emissions by 40%.

A new three-stage cooling system improves cold-start heating and in-cabin heater performance. The first circuit circulates water only through the cylinder head, EGR cooler and heat exchanger. As the engine warms, a second circuit opens to move water through the crankcase. The third cooling circuit modulates intake air temperature.