The New Diesel Passenger Cars

Diesel engines in passenger vehicles have long been popular in Europe. More than 50 percent of new cars sold in Europe are diesel powered.

Some stateside Mercedes passenger vehicles and a few Jeep Grand Cherokees have diesels, but most US diesels are in heavy-duty pickups. The American market for diesel-powered vehicles is close to achieving critical mass. Diesel powered passenger vehicles will soon be seen on US roads.

After spending thousands of cold nights sleeping only a few feet from a rattling, vibrating diesel engine, and breathing the sooty exhaust for a living, I was skeptical about plans to introduce diesel vehicles to the US passenger car market.

But now some analysts predict that thrifty diesels will outsell hybrid-powered vehicles in a couple seasons.

Researchers at J.D. Power and Associates predict that diesel engined autos will account for more than 10 percent of American passenger car sales by 2015.

The New Diesels: Clean and Green

With stirrings in Congress for increased Corporate Average Fuel Economy (CAFE) and a carbon emissions scare in progress at EPA, changes are coming to the US auto industry.

If a Democratic victory seems inevitable for 2008, the auto industry may support quick lame-duck legislation to pre-empt more radical regulation.

New designs have transformed the car-sized diesels from the slow, noisy, sooty powerplants of the 1980's.

The new diesel powered vehicles are seen as a green alternative to pricey hybrids. Hybrids, as currently implemented, are most economical in stop and go traffic. At highway speeds, the hybrid's engine is doing all the work, so real highway mileage can be less than the EPA advertised. Most US driving is highway miles, which includes commuting.

Diesel vehicles excel at highway mileage.

Because diesel fuel packs more energy per pound than gasoline, diesel vehicles offer 30 percent better fuel economy than gas powered cars.

And less fuel burned means less carbon dioxide greenhouse gas.

Distilled in the same refineries as gasoline, diesel fuel has historically been high in sulfur.

But new Ultra Low Sulfur Diesel (ULSD) requirements from the Environmental Protection Agency have spurred the evolution of cleaner, quieter small diesels.

Hybrids are the target. Both diesel and hybrid vehicles have a cost premium at purchase. The diesel price bump is expected to be about half that for a hybrid. At current fuel prices, hybrids must run for many miles to reach a payback point. The break-even point is close to the life expectancy of the battery pack.

Diesel drivers may recover the initial premium in as little as four years after the vehicle’s purchase. Those running high miles will hit break-even sooner. After that there is profit.

I have seen well maintained commercial diesels go 1 million miles before major overhaul. How long will the car diesels last?

Auto manufacturers remember the disaster that happened to the tire business when radial tires, lasting 40K miles, displaced bias-ply tires, which lasted 10K miles. They won't build cars that last.

Diesel's efficiency advantage, relative to hybrids, is greatest in larger vehicles operated on the highway. Crossovers and SUVs will be the initial applications.

New post-combustion technologies, particulate traps and oxidative converters, clean up the once noxious exhaust.

Urea injection systems blow a biodegradable, ammonia-based mist into the exhaust gas, where a catalyst reduces oxides of nitrogen and carbon monoxide.

EPA is on record as opposing urea injection because it relies on periodic servicing to maintain clean emissions. Can drivers be trusted to refill the urea tank?

Turbos and computer controlled fuel injection cure the diesel's reputation as a noisy slowpoke.

Computer assisted engine design has shaved weight, making modern diesel passenger car engines lighter and higher revving.

By 2009, diesel cars will meet the identical emissions standards required of gasoline powered vehicles.

Vehicle Builders Announce Diesels

The Germans (Mercedes, BMW, and VW), have the lead in diesel technology, closely followed by Honda. Toyota is heavily invested in hybrids, but has purchased an interest in diesel builder Isuzu.

The 2007 Mercedes-Benz E320 Bluetec is the first automobile sold in the US to burn low-sulfur diesel.

Mercedes has built diesel passenger cars since the 1930s and leads in diesel technology.

Mercedes' E320 Blutec features a three-liter turbocharged V6 diesel. Making 208 hp at 3800 rpm and 388 lb-ft of torque across a wide rpm band, the new mill propels the 3860 pound sedan from 0-60 in just 6.6 seconds.

What is most impressive is the 27 mpg city/37 mpg highway EPA fuel economy ratings which accompany the performance. A 21 gallon fuel tank allows highway cruising range to 700 miles.

The 2007 Mercedes-Benz E320 Bluetec proves that, in luxury vehicles, diesels can be fast and economical.

Great, but the E320 options out near $60K, what about the rest of us?

The Detroit 3-again, lagging in diesel technology, are racing to build fuel-saving diesel engines for their domestic light trucks.

Volkswagen promises a 50-state-legal (California compliant) diesel in Jettas, and possibly New Beetles, by early 2008

The 140 hp diesel Jetta is estimated to deliver 45 mpg on the highway.

Honda recently announced advanced converters eliminating the need for controversial urea injection. Honda aspires to deliver 50-state -clean diesel cars in 2009.

GM plans to offer diesel engines in Saturn Aura and a Cadillac sedan around 2010.

By then, Honda, BMW, the New Chrysler, Nissan, and Audi will produce diesel-powered passenger cars and SUVs.

Ford Motor Co. says it has no plans to offer diesel cars, citing the cost premium in passenger cars. Yes, a $3000 premium for a diesel engine on a $15,000 compact car is a deal killer. But luxury cars, crossovers, and sport utility vehicle buyers can absorb the initial cost. These sophisticated consumers can calculate the payback period.

So, in the short term, hybrid technology is the green solution for compact cars and diesel engines should be considered for mid-sized and up. Could this be Honda's reason for dropping the Accord Hybrid for 2008?

Used diesels have higher resale prices, they last longer.

Consumers can anticipate a bunch of clean, quiet diesel cars coming by 2009. Presently only 5 percent of America's passenger fleet is diesel powered, but this is the fastest changing car market since the 1920's.