These days, one look at the prices posted at local gas stations can quickly throw vehicle owners into sticker shock. With the cost of fuel on the rise, diesel engines provide an attractive alternative to gasoline-burning vehicles. Although diesel engines have been around for eons, advances in technology and more stringent environmental regulations have prompted engineers to clean them up for modern-day use. As a result, the number of manufacturers entering (or reentering) the diesel market is increasing.
Mercedes-Benz brought its first turbodiesel sedan, the 300 SD, to American shores in 1977, and continued to offer diesel products in the U.S. through 1999, the last year the E300 Turbodiesel was sold here. In 1997, Mercedes introduced the world's first diesel engine with common-rail direct injection (CDI), but this bit of technology was initially limited to the European market. This CDI engine was the first application of an electronic fuel injection system for diesels, and was expected to make its way across the pond in a few years' time.
However, when the E-Class sedan was freshened for the 2000 model year, the previous diesel engine would no longer fit under the new, lower hood, so Mercedes decided to take a one-year hiatus from the American diesel market (with the intention of bringing the CDI engine to the U.S. in 2001). But, the brief hiatus extended itself another four years while Mercedes engineers perfected the CDI engine for entrance into the American market with the debut of the 2005 E320 CDI. Prospective buyers should note that the new diesel Benz will only be sold in 45 of our 50 states, as it will still not be able to meet the strict emissions requirements in California, Maine, Massachusetts, New York and Vermont.
The benefits of diesel engines are old news to Europeans. Diesel engines are reputed to get 20 to 30 percent better fuel economy and produce 20 to 30 percent less carbon monoxide and carbon dioxide than gasoline engines. With the cost of fuel in Europe near $5 per gallon, how could even a stodgy Brit argue with the convincingly low fuel consumption? But whatever the benefits, the drawbacks of diesel are well-known, too, mainly due to the inherently dirty, smelly properties of diesel fuel. Sulfur that is naturally present in diesel fuel is the main cause of high diesel tailpipe emissions. In untreated diesel fuel, there are as many as 500 parts per million of sulfur, but in recent times the maximum allowable content has been reduced to 350 ppm, allowing diesel engines to produce less unpleasant soot. This "clean" diesel fuel will become available in the U.S. in 2006. It's already in use in Europe, and is nearly sulfur-free, thus eliminating the yucky black smog.
But not only does the E320 CDI benefit from the current cleaner fuel, the CDI technology itself also improves the performance of diesels as we know them. CDI electronic injection provides more injection quantity control, which results in more power and lower exhaust emissions. Another CDI benefit is the high fuel pressure that is always available as soon as the injector valve opens, for as long as it stays open. Mechanical injection pumps used to require gradual buildup, but the CDI provides constant pressure and, therefore, greater torque. This makes the sedan's 3.2-liter, turbocharged inline six-cylinder feel invincible with its staggering torque rating of 369 pound-feet, which is available almost instantaneously at the push of the accelerator pedal. By comparison, the gasoline-equipped E320 also displaces 3.2 liters with its naturally aspirated V6 engine, but with a torque rating of only 232 lb-ft. Also, the E320 CDI gets 27/37 mpg for city and highway driving, respectively, compared to the E320 gasoline engine fuel economy of 19/27.
Drawing upon the speed and precision of the CDI electronic injection, Mercedes engineers found that by igniting a small quantity of fuel twice in rapid succession — before the main injection preheats the combustion chamber — they could make the pressure and temperature increases more gradual, and smooth out those spikes that result in the typical diesel noise. All of this means that the rumbling and clattering that used to signify the presence of a diesel-powered vehicle is nearly undetectable. In colder climates, you may be greeted with more diesel rumble upon startup, but as we learned during our stop-and-go test-drive through the southern U.S., when the engine was warm, you really had to listen at the engine compartment for the telltale tune of a diesel.
Beyond its power plant, there is little to distinguish the CDI from its gasoline-powered sibling. Both use the same standard five-speed automanual transmission, and have the same four-link front suspension design and five-link rear suspension. Power-assisted rack-and-pinion steering is also present, as is the Electronic Stability Program (ESP), a stability control system that comes standard on all Mercedes vehicles.
In fact, the V6 and inline six are nearly identical with the only interior CDI mark being the presence of a warning light for the glow plug operation. Outside, bystanders will be forced to scan the rear deck lid for the CDI emblem, especially when no diesel noise pollution is present as a giveaway.
Pricing for the 3,000 CDI units slated for U.S. allocation has not yet been announced, but Mercedes reps tell us that it will compete with the gasoline-powered E320 model, which has a base price of $48,795 (including destination). A 4Matic all-wheel-drive version of the diesel sedan is also scheduled to find its way into U.S. showrooms as soon as the year ends.
Although some consumers complain that diesel fuel is not available at all gas stations, our appreciation of the E320 CDI encourages us to point out that its availability increases each year and it costs approximately the same as midgrade unleaded gas. With the E320 CDI's 30-plus mpg fuel economy allowing fewer trips to said gas stations, we'd be hard-pressed to find fault with this E-Class iteration, which offers both fuel economy and luxury — certainly a mark of a well-rounded premium sedan.
Mercedes-Benz brought its first turbodiesel sedan, the 300 SD, to American shores in 1977, and continued to offer diesel products in the U.S. through 1999, the last year the E300 Turbodiesel was sold here. In 1997, Mercedes introduced the world's first diesel engine with common-rail direct injection (CDI), but this bit of technology was initially limited to the European market. This CDI engine was the first application of an electronic fuel injection system for diesels, and was expected to make its way across the pond in a few years' time.
However, when the E-Class sedan was freshened for the 2000 model year, the previous diesel engine would no longer fit under the new, lower hood, so Mercedes decided to take a one-year hiatus from the American diesel market (with the intention of bringing the CDI engine to the U.S. in 2001). But, the brief hiatus extended itself another four years while Mercedes engineers perfected the CDI engine for entrance into the American market with the debut of the 2005 E320 CDI. Prospective buyers should note that the new diesel Benz will only be sold in 45 of our 50 states, as it will still not be able to meet the strict emissions requirements in California, Maine, Massachusetts, New York and Vermont.
The benefits of diesel engines are old news to Europeans. Diesel engines are reputed to get 20 to 30 percent better fuel economy and produce 20 to 30 percent less carbon monoxide and carbon dioxide than gasoline engines. With the cost of fuel in Europe near $5 per gallon, how could even a stodgy Brit argue with the convincingly low fuel consumption? But whatever the benefits, the drawbacks of diesel are well-known, too, mainly due to the inherently dirty, smelly properties of diesel fuel. Sulfur that is naturally present in diesel fuel is the main cause of high diesel tailpipe emissions. In untreated diesel fuel, there are as many as 500 parts per million of sulfur, but in recent times the maximum allowable content has been reduced to 350 ppm, allowing diesel engines to produce less unpleasant soot. This "clean" diesel fuel will become available in the U.S. in 2006. It's already in use in Europe, and is nearly sulfur-free, thus eliminating the yucky black smog.
But not only does the E320 CDI benefit from the current cleaner fuel, the CDI technology itself also improves the performance of diesels as we know them. CDI electronic injection provides more injection quantity control, which results in more power and lower exhaust emissions. Another CDI benefit is the high fuel pressure that is always available as soon as the injector valve opens, for as long as it stays open. Mechanical injection pumps used to require gradual buildup, but the CDI provides constant pressure and, therefore, greater torque. This makes the sedan's 3.2-liter, turbocharged inline six-cylinder feel invincible with its staggering torque rating of 369 pound-feet, which is available almost instantaneously at the push of the accelerator pedal. By comparison, the gasoline-equipped E320 also displaces 3.2 liters with its naturally aspirated V6 engine, but with a torque rating of only 232 lb-ft. Also, the E320 CDI gets 27/37 mpg for city and highway driving, respectively, compared to the E320 gasoline engine fuel economy of 19/27.
Drawing upon the speed and precision of the CDI electronic injection, Mercedes engineers found that by igniting a small quantity of fuel twice in rapid succession — before the main injection preheats the combustion chamber — they could make the pressure and temperature increases more gradual, and smooth out those spikes that result in the typical diesel noise. All of this means that the rumbling and clattering that used to signify the presence of a diesel-powered vehicle is nearly undetectable. In colder climates, you may be greeted with more diesel rumble upon startup, but as we learned during our stop-and-go test-drive through the southern U.S., when the engine was warm, you really had to listen at the engine compartment for the telltale tune of a diesel.
Beyond its power plant, there is little to distinguish the CDI from its gasoline-powered sibling. Both use the same standard five-speed automanual transmission, and have the same four-link front suspension design and five-link rear suspension. Power-assisted rack-and-pinion steering is also present, as is the Electronic Stability Program (ESP), a stability control system that comes standard on all Mercedes vehicles.
In fact, the V6 and inline six are nearly identical with the only interior CDI mark being the presence of a warning light for the glow plug operation. Outside, bystanders will be forced to scan the rear deck lid for the CDI emblem, especially when no diesel noise pollution is present as a giveaway.
Pricing for the 3,000 CDI units slated for U.S. allocation has not yet been announced, but Mercedes reps tell us that it will compete with the gasoline-powered E320 model, which has a base price of $48,795 (including destination). A 4Matic all-wheel-drive version of the diesel sedan is also scheduled to find its way into U.S. showrooms as soon as the year ends.
Although some consumers complain that diesel fuel is not available at all gas stations, our appreciation of the E320 CDI encourages us to point out that its availability increases each year and it costs approximately the same as midgrade unleaded gas. With the E320 CDI's 30-plus mpg fuel economy allowing fewer trips to said gas stations, we'd be hard-pressed to find fault with this E-Class iteration, which offers both fuel economy and luxury — certainly a mark of a well-rounded premium sedan.
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