Far from the smelly and messy clatter traps of twenty years ago, cars and SUVs powered by modern diesel engines run cleaner and more efficiently as automakers increase and improve the offer.
Guess what's coming back: Diesel engines.Automakers have introduced new diesel-powered models during 2004, and there are more in the pipeline.
Mercedes-Benz, which in 1936 debuted the 260 D, the world's first diesel car, is offering its first diesel model in several years: the 2005 E 320 CDI sedan.
With a highway fuel economy rating of 6.3 L/100 km (44 mpg) and a whopping 369 lb/ft of torque coming on as low as 1800 rpm, the six-cylinder-powered E 320 CDI can appeal to both fuel-conscious buyers and sport-minded drivers.
Indeed, the E 320 CDI's torque is 59 per cent greater than the 232 lb/ft at 3000 to 4800 rpm of the E 320 sedan's gasoline engine. The 201-horsepower diesel sedan's 0-100 km/h of 8.3 seconds is very close to the 7.7 seconds we recorded aboard the 221-hp E 320 gasoline-fed model, with our trusty electronic accelerometer.
Outstanding Diesels for SUVs Too
Not to be outdone, Volkswagen is now offering its award-winning 5.0-litre turbodiesel V10 in what has become the top model of the Touareg sport-utility line-up. This state-of-the-art engine delivers an amazing 553 lb/ft of torque at 2000 rpm, which helps vault the Touareg TDI from 0 to 100 km/h in a truly amazing 7.2 seconds, while letting this three and a half ton (3155 kg / 6956 lb) luxury SUV consume only 10.8 litres of diesel fuel per 100 kilometres of highway.
Moreover, VW has again made available a turbocharged diesel engine in its Passat GLS mid-size sedans and wagons. This thoroughly-modern 2.0-litre power plant has leading-edge common rail injection technology and produces a modest 134 horsepower but an impressive 247lb/ft of torque at a low 1900 rpm: Enough to accelerate the sedan from 0 to 100 km/h in an average of 10.4 seconds, in our usual electronic measures. A thoroughly acceptable performance, coupled to a highway fuel economy rating of 6.9 L/100 km.
For the 2005 model year, Jeep is adding a 2.8-litre turbocharged four-cylinder diesel to the list of options for its Liberty SUV. This new Italian-made (by top diesel specialist VM Motori) engine delivers a 295 lb/ft torque peak, which is more than even the Liberty's 3.7-litre gas V6 engine, rated at 235 lb/ft.
While larger SUVs such as the Ford Excursion have been offered with diesel engines over the years, the Liberty marks the first smaller-size SUV to offer a diesel option in almost twenty years, in the North American market. Ironically, Jeep had also been the last to have such a model: The Jeep Cherokee equipped with an optional Renault-built, 81-hp turbodiesel unit and first offered as a 1985 model.
All this comes at a moment when consumers are becoming more familiar with fuel-efficient gasoline-electric hybrids and begs the questions: Why diesels-and why now?
Diesels Didn't Disappear
Many consumers might have thought that diesel-powered passenger vehicles had, for the most part, disappeared from the market. It's true that interest in diesels on this continent, particularly in cars, had faded since the early 1980s when car buyers were more focused on fuel efficiency. Back then, even General Motors built and sold diesel-powered cars in this country.
As the memory of the oil shocks of the 1970s went away, buyers began to eschew diesels in favour of internal combustion engines that burn gasoline. Truth was, the old diesels could be loud, making the usual diesel engine racket under the hood. They were often also smelly, with telltale blue or black smoke, and familiar fuel odours emitting from the tailpipe.
"The technology of the time left a bad taste in the mouths of many and a lot of bad memories of smokey, smelly, clatter-trap cars," acknowledged Dieter Zetsche, president and chief executive officer at Chrysler.
With publicized concerns cropping up over the years about diesel emissions possibly being deleterious to health, it's not surprising that the demand for diesels in this country fell. However, diesel demand continued in the large pickup truck segment, where torque, towing performance, better fuel economy and long-term durability are areas where diesels can excel.
Europe Embraces Diesels
Diesels certainly didn't disappear in Western Europe, where they represent an estimated 35 per cent to 40 per cent of new models sold. Indeed, anyone who has visited France, Italy or Austria lately can attest to the widespread use of diesel cars. In France, diesels are in an estimated 60 per cent of new cars sold. In Austria: it's 70 per cent or more.
Chief reasons for popularity of diesels in Europe: The price of diesel is lower than that of gasoline, and diesel engines have greater fuel efficiency than gasoline engines. (It helps that filling stations often provide free gloves to keep drivers' hands from getting that diesel smell on them.)
Europeans also have come to prize the new diesel engines for their strong torque - an amazing amount of get up and go can be found in a diesel car - and for their durability.
Diesel Progress
Diesels has been improving and aren't the same as they were about 20 years ago.
Today's diesel engines for cars tend to use Common-rail Direct Injection technology - which is what the "CDI" in the Mercedes E 320 CDI model stands for, for example. This rail is a shared delivery "pipe" for all fuel injectors and allows the diesel fuel to get into engine cylinders at a consistent, very highly pressurized rate - roughly 23,000 psi in the E 320 CDI.
Electronic fuel injection systems used in today's diesel cars allow for varied injection timing and adjustment of the quantity of fuel injected, so vehicles can better respond to driver demands. Diesel engines for today's cars also tend to be turbocharged to ensure strong performance characteristics.
The electronics and common rail technology, along with newer particulate filter installations, have also helped the newer diesel engines better meet ever-stricter diesel emission regulations.
Things will get even better when cleaner diesel fuel, with less sulphur content than what is currently allowed, becomes available in this country. The currently timetable is for 2006.
North America Changing
No one in the auto industry is predicting that North Americans will join Europeans in their level of interest in diesels. Nonetheless, there are signs that things here are changing.
As gasoline prices increased over the last few years and even more so in recent months, Mercedes-Benz officials note that they have received regular requests from consumers who remember the carmaker's diesel-powered cars.
There are plenty to remember, since in the early 1980s more than 75 per cent of the Mercedes cars sold on this continent were diesel-powered. The last Mercedes with a diesel engine in this country was the E 300 Turbodiesel, which left the market in 1999.
Bharat Balasubramanian, vice president of engineering technologies and regulatory affairs at the Mercedes car group, said more than 50 per cent of the diesel-powered cars sold on the continent are "still running here on the roads."
Volkswagen, which never stopped selling diesel-powered versions of its Golf and Jetta models over the years and currently offers diesels in its New Beetle and Passat models, says its diesels are well received and never languish on dealer lots.
Indeed, a base Golf GL four door with 2-litre four-cylinder gasoline engine and manual transmission is rated at 9.8 L/100 km in city driving and 7.6 L/100 km on the highway. By comparison, a Golf GL four door with 1.9-litre turbocharged four-cylinder diesel engine is rated at 6.2 L/100 km in the city and 5.1 L/100 km on the highway.
Note that the 100-horsepower diesel engine in the Golf generates 177 lb/ft of torque starting as low as 1800 rpm and continuing to 2400 rpm for good acceleration and response, while the 115-horsepower gas engine in the Golf GL develops only 122 lb/ft of torque at 2600 rpm.
Challenges Ahead
Consumers need to know and be convinced that diesel engines of today aren't the same as the noisy ones from 20 years ago.
The best way to evaluate diesels is to test drive the new models that have them and compare these vehicles, back to back, with gasoline-powered versions of the same models.
The results could surprise you. For example, the '05 Mercedes-Benz E 320 CDI contains extra soundproofing and engine technology to help reduce the usual diesel engine rattle, or clatter, that's usually heard under the hood.
As a result, some consumers might be hard-pressed to notice, by the sound, that this new model is a diesel. Tests by Mercedes show the car is the quietest diesel the company has ever offered in Canada, with sounds at idle a mere 44 decibels compared with 42 decibels for the comparable gasoline-powered E-Class sedan. At full throttle, the diesel model actually is slightly quieter than the gasoline model, with noise measured at 72 decibels vs. 76 decibels from the gasoline engine.
Meantime, automakers are examining price in the whole consumer-appeal equation.
VW's Touareg with 310-horsepower V10 has a starting MSRP of $85,400. This is a stout $22,090 more than a Touareg with a 4.2-litre V8 that also delivers 310 horsepower but only 302 lb/ft of torque between 3000 and 4000 rpm.
Diesel cars in Europe typically come with a smaller price premium of $1,400 or more, versus a comparable gasoline model.
In Canada, VW's diesel-powered Golf GL hatchback with a manual transmission has a starting MSRP of $22,290, which is $2,060 higher than a comparable gasoline-powered Golf GL.
Mercedes put a $1,400 price premium on its 2005 E 320 CDI over the 2005 E 320 gasoline-powered six-cylinder sedan. The E 320 CDI has a starting MSRP of $74,400, to the latter's $73,000.
Despite all the changes, though, only time will tell how receptive Canadian consumers are to the rising number of diesel offerings.
But when some of our readers in Alberta start expressing an interest in diesel-powered cars because of rising fuel prices, we are inclined to believe that their more modern proponents have a bright future.
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| Jeep is bringing back the diesel engine's superior torque and frugality to the mid-size SUV class 20 model years after offering it in its landmark Cherokee. |
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| The Jeep Liberty CRD's engine is a 2.8-litre turbocharged four-cylinder unit by Italian diesel specialist VM Motori. It delivers a sturdy 295 lb/ft of torque. |
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| Mercedes-Benz pioneered diesel engines in passenger cars, back in 1936. This 2005 E 320 CDI sedan is its first diesel automobile since 1999. |
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| The Mercedes-Benz E 320 CDI's state-of-art 3.2-litre engine also uses high-pressure 'common-rail' direct injection to increase efficiency and lower emissions and fuel consumption. |
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| Volkswagen's support of the diesel engine never wavered in North America. For more than three decades, it was championed by its Rabbit, Golf (here), Jetta and Passat model lines. |
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| VW's award-winning, hugely powerful and remarkably stingy 5.0-litre turbodiesel V10 was offered here only briefly, under the hood of the carmaker's Touareg luxury SUV. |
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| Smart currently offers the littlest diesel engine in Canada; a 0.8-litre, 41-horsepower three-cylinder unit, as the only power plant available in its new Fortwo Cabrio and Coupé models. |