Well Toto, we’re not in a Kenworth anymore. In fact, there’s never been a diesel quite like this one. In an automotive first, Mercedes began producing passenger diesels in 1936, three years before the one in which Toto and Dorothy ran in theaters. A period of worldwide strife followed, but soon after you could acquire Mercedes diesels here in America. Sales of these peaked in the 1980s, a victim of clean air legislation and the taint given all such engines by the General Motors versions of them. Soon, all that cheap diesel fuel and road-warrior romance wasn’t worth a load of postholes as people began regarding the cars as stinking, noisy, soot-spewing nuisances ill-suited to the demands of me-generation status-acquisition.

Perhaps that’s why today it comes as a surprise that – in addition to getting better mileage – those diesel engines produced about 25% fewer carbon dioxide emissions than did their conventionally fueled counterparts.

Improving on this, the new six-cylinder Mercedes E320 CDI uses fully electronic fuel injection not only to further lower diesel emissions, but to moderate the engines’ noise. Moreover, the car’s CDI – or “Common-rail Diesel Injection” technology – supplies the motor’s injectors with a constant flow of fuel under very high pressure. This combines with the heat of highly compressed air to combust fuel in a way that obviates the need for spark plugs. According to the company’s product PR specialist Michelle Murad, this not only makes the new power plant more economical than were diesels of yore, but faster as well.

By reducing their traditionally undesirable aspects, Volkswagen, Jeep, and Mercedes are trying to bring back diesels as attractive alternatives to both hybrid and conventional engines. That said, we should note that because diesels release higher amounts of nitrogen oxides than do gasoline-powered cars, they aren’t sold in states with the most-stringent emissions standards, including California and New York.

Smokeless, odorless, and significantly quieter than previous diesels, the new Mercedes motor can be found bolted into the engine bay of one of its midrange E-Series luxury cars, the E320. E-Series cars are German-built rear-drivers (all-wheel drive is an option on some models) that are spruce iterations of the rakish yet dignified styling of Mercedes. Mercedes builds its E-Series cars as solidly as the Emerald City and makes them go like flying monkeys. All come with traction control, curtain side airbags, TeleAid road assistance, and antilock brakes.

As an E320, our “Granite Grey” test car had 16-inch wheels. Its luxurious leather and walnut-trimmed interior played against the notion that there’s no place like home. The smart dashboard contained large gauges that were easy to use (as long as you weren’t fussing with the screen-based auto system), and ample front seats employed Dynamic Drive systems that inflate bolstering in response to maneuvers. (Blow-up dolls are probably more practical on an everyday basis, but we appreciated the wow factor). Back seats were supportive, although an occupation by more than two passengers seriously taxed their capacity for comfort.

As a CDI, the $50,000 test car had a turbocharged version of the 201-horsepower six described so effusively above. This engine enables the CDI to claim a fuel economy rating of between 27 and 37 miles a gallon. For at least part of the time, we headed the thing toward Kansas.

The solid-feeling CDI fires up with a light rush of diesel clatter that soon disappears into the car’s solid-feeling ambience. Initial acceleration seems stifled – as if one were pushing a bank safe into the wind on a cushion of air – but owing to the torque delivery made possible by the car’s fuel injectors and turbocharger, further acceleration can whisk you up to speed as if borne aloft on a tornado. Once there, E320 drivers will find that the car’s ride quality remains stable while its steering performs nimbly, both effects enhanced by driver-controlled suspension-tuning features. Finally, the cornering E320 enjoys certain grip and controlled lean, although its strong brakes lack progressive feel.

It’s not as roomy as a Lexus LS 430 or as nimble as a BMW 5 Series, but get behind the wheel of an E320 CDI and your cares will melt away like a wetted wicked witch. Besides, as a luxurious high-tech diesel, the Merc really hasn’t very much American competition.