Mercedes GL420 Diesel Reduces Emissions

While Japanese automakers seem to think gas-electric hybrid engines are the fuel-saving technology of choice, European manufacturers have stayed loyal to diesels. Diesel is popular in the Old World, as it gets around 30 percent better mileage than conventional gas. Unfortunately, it also has a reputation for sooty, particulate-filled exhaust. That's supposed to change with the newest round of diesel cars.

One of them is Mercedes-Benz's Vision GL420 Bluetec concept, an adaptation of the GL-Class SUV that combines the automaker's latest emissions technology with a V-8 diesel engine to deliver an estimated 24 mpg. Bluetec engines use a series of particulate filters and specialized catalytic converters to reduce particulate and nitrogen oxide emissions, two major culprits behind the legislative hurdles that have prevented the use of diesel fuel in several states.

• GL420 Bluetec makes 290 horsepower and 515 pounds-feet of torque
• The diesel-powered GL320 CDI, whose non-Bluetec V-6 makes 215 hp and 398 pounds-feet of torque
• Gas-powered GL450, whose V-8 makes 335 hp and 339 pounds-feet of torque.
• Mercedes says that the GL420 Bluetec gets around 24 mpg in combined city and highway driving, a figure that beats the GL320 CDI (23 mpg) and GL450 (16 mpg).