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BLUETEC: The Cleanest Diesel in the World

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January 11, 2006

BLUETEC: The Cleanest Diesel in the World

BLUETEC: The Cleanest Diesel in the World

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January 12, 2006 With the launch of the E 320 BLUETEC in the USA later this year, Mercedes-Benz will be offering the first series production car with BLUETEC diesel technology. The automotive manufacturer with the world's longest diesel tradition has modified specific aspects of the economical, powerful and robust 320 CDI engine, adding state-of-the-art emission-control technology to make it the cleanest diesel in the world. Mercedes-Benz has thus transformed the diesel engine into a clean and future-compatible system. The six-cylinder diesel engine combines V8 power with four-cylinder consumption: 155 kW/211 hp maximum output and 540 Nm maximum torque despite average fuel consumption of just 6.7 l/100 km or 35 mpg. BLUETEC technology is capable of producing the cleanest diesel vehicles in the world, and is more than capable of meeting the most stringent emissions regulations.

The BLUETEC vehicles that DaimlerChrysler showcased in Detroit at the NAIAS – the Mercedes-Benz E 320 BLUETEC, the Vision Mercedes-Benz GL 320 BLUETEC, and the Concept Car Jeep Grand Cherokee BLUETEC – are capable of being the most fuel-efficient and cleanest diesel passenger vehicles in their segments in the U.S.

BLUETEC can only achieve its full effect in passenger cars when it is used with diesel fuel that has a sulfur content of less than 15 ppm. Such fuel will further reduce the emissions of diesel vehicles already on the market in the U.S. This low-sulfur diesel has already been introduced throughout Europe and is expected to become available in the U.S. in the Q3 of 2006. DaimlerChrysler's first BLUETEC passenger car will be the Mercedes-Benz E 320 BLUETEC, which will be launched in the U.S. in Q3, 2006.

Offering its customers the very best has become something of a maxim at Mer-cedes Benz, not least when it comes to designing and constructing vehicles. This is especially true in the case of diesel, a drive technology which now accounts for more than 50 percent of the European market thanks mainly to the fact that it offers excellent economy, longevity and robustness without compromising on driving enjoyment. Economically state-of-the-art diesel vehicles from Mercedes-Benz are one answer to the unstoppable rise in fuel prices, including in the US. Now, the brand's innovative BLUETEC technology makes the already economical diesel alternative cleaner than ever before.

Mercedes-Benz was the first to implement Rudolf Diesel's combustion principle in a passenger car engine some 70 years ago. This technology is far more efficient than the gasoline engine and has been optimized over a period of many years. One innovation in particular – the common-rail direct injection system in conjunction with four valves per cylinder introduced in 1997 – has had a major impact on the development of the modern diesel engine. Since then, the abbreviation CDI has come to stand for unsurpassed fuel economy and a major boost in torque – which means it has better pulling power and is more fun to drive, meaning that diesel vehicles are often superior to similarly powered gasoline models.

If diesel models previously had any disadvantages compared to their gasoline counter-parts, then these related to specific diesel emissions, especially particulate matter and nitrogen oxides. However, since the introduction of the maintenance-free particulate filter for its diesel passenger cars in autumn 2003, Mercedes-Benz has also brought about a substantial reduction in particulate matter. And although it has succeeded in cutting nitrogen oxide emissions by some 75 percent through engine modifications alone in the past 15 years, Mercedes-Benz wants to go even further still. The objectives are clear: innovative exhaust gas aftertreatment methods give Mercedes Benz diesel engines the potential to comply with the world's most stringent emission standards and to be available in all 50 US states. In other words, Mercedes Benz will be able to offer the cleanest diesel in the world in every vehicle category. BLUETEC is the name for this new generation of high-tech diesel drives that will initially be launched in the US.

Today's Mercedes-Benz diesel engines also stand for agility, sportiness and reliability, as demonstrated before a world public last spring when three standard-specification E 320 CDI models broke a clutch of impressive records in Laredo (Texas). For one, a new average speed record of 224.823 km/h (139.699 mph) was set in a 30-day endur-ance test covering over 100,000 miles (160,934 km). These vehicles were also fitted with a sophisticated emission-control system, including a standard-specification main-tenance-free particulate filter. This meant that they were easily able to undercut the currently applicable EU 4 emission limits – a feat confirmed in the tests conducted by the TÜV (German technical inspection authority) following the grueling record-breaking drives.

The first BLUETEC vehicles available to customers in the US will be E 320 BLUETEC models, due for launch in Q3 2006. As well as delivering renowned economy, performance and reliability, these models comply with the world's most stringent emission standards.

By the time the BLUETEC generation is launched in the US in autumn 2006, low-sulfur diesel with a maximum sulfur content of 15 ppm will be available, thus reducing the previous upper limit of 500 ppm by a factor of 33. The US Environmental Protection Agency (EPA) has therefore laid the foundations for establishing sophisticated, fuel-efficient diesel vehicles in the US. This will result in a dramatic and immediate reduction in the emissions of all diesel vehicles in the US, representing a major step towards cutting emission levels in general. Sulfur, which occurs in mineral oil to varying degrees, has a corrosive effect in the engine as well as being a major cause of particulate matter. The introduction of a low-sulfur diesel fuel will enable the use of particulate filters and efficient nitrogen oxide after-treatment.

BLUETEC – leading-edge drive system

High torque and pulling power even at low engine speeds, impressive range and economic efficiency are decisive factors in the buying decisions of most motorists, including those in the US. Vehicles equipped with sophisticated diesel engines made by Mercedes-Benz are ideal for fulfilling these criteria, since they minimize fuel consumption while maximizing torque, range and driving enjoyment. In addition, they are extremely robust. Accompanied by innovative BLUETEC technology, this power-train has the potential to fulfill even the most stringent of emission requirements world-wide and specifically, in all 50 US states. Furthermore, it is ideally suited to the vehicle genres that are popular in the US such as large luxury sedans, SUVs, mini-vans, trucks and pickups. In addition, diesel really comes into its own in the traffic conditions that prevail in the US; steady cruising speeds on highways and long city-to-city distances.

This is even more important in a global situation in which energy and crude oil costs are expected to rise over the longer term. Diesel engines consume between 20 and 40 percent less fuel than their gasoline counterparts. In Western Europe, where fuel prices are double what they are in the US, a large number of motorists have already made the switch. More than half of European customers now opt for diesel passenger cars.

As fuel prices continue to rise in the US over the longer term, fuel economy will become a more important criterion when buying a new car. This is why analysts expect demand for clean diesel drive systems such as Mercedes-Benz BLUETEC to increase in the US, as in other countries. J.D. Power and Associates, a leading market research institute, forecasts that the market share for diesel passenger cars in the US, which currently stands at around 3.4 percent, will quadruple by the year 2015. Mercedes-Benz is convinced that, once BLUETEC technology has established itself, this forecast will appear conservative rather than optimistic.

Customers who opt for diesel models are especially appreciative of their excellent fuel consumption figures in real day-to-day driving conditions, which are very close to and sometimes even better than the officially quoted fuel consumption figures. One example of this was seen in a long-distance coast-to-coast fuel consumption test involving a Mercedes-Benz ML 320 CDI, carried out in the US by a German car magazine. On the route from New York to San Francisco, the all-wheel drive SUV consumed an average of just 9.2 liters per 100 km (equivalent to 25.6 mpg).

The latest example of outstanding economy was seen in a test drive involving a Mercedes-Benz S-Class featuring the new 320 CDI engine on a stretch of the famous Route 66 between Chicago and Los Angeles. In this test, conducted by two freelance journalists over a distance of 3563 km (2214 miles), the average fuel consumption came in at 6.5 liters per 100 km (36.2 mpg).

Diesel vehicles reduce dependence on oil imports

BLUETEC is not just the cleanest diesel technology in the world. It also ensures low fuel consumption in real terms, helping customers to make tangible fuel savings and, therefore, reducing the economy's dependence on oil imports. In the US, where there are concerns about ensuring fuel supplies over the longer term, this technology is set to play a key role, especially when one considers the fuel consumption advantages for the extremely popular SUVs and pickups (light trucks) which, as it stands, are pre-dominantly powered by large-displacement V8 gasoline engines.

Margo Oge, Head of the Office of Transportation and Air Quality at the US Environmental Protection Agency (EPA) presented the following figures back in March 2004: "If we had a light duty vehicle population that was one third diesels, that could save up to 1.4 million barrels of oil per day in the US, the amount of oil the US currently imports from Saudi Arabia. If we made these vehicles diesel hybrids, the oil savings would about double or up to 2 times the amount of oil Saudi Arabia ships to the US every day."

BLUETEC – the emission-control technology from Mercedes-Benz

The Mercedes-Benz development engineers have been advancing emission-control solutions for a number of years, one of the main aims being to ensure compliance with future emission standards in the US, Europe and Asia. One focus of these activities is devising effective and economical methods for reducing nitrogen oxides ("denoxing"). This technology for the cleanest diesel in the world is called BLUETEC.

In order to bring together all these technologies within a single, appropriate package, Mercedes-Benz is following a graduated plan that includes the following phases: • Optimization of the engines and their combustion processes to minimize untreated emissions. This includes electronic engine management, four valves per cylinder, third-generation common-rail direct injection with piezoelectric injectors, a turbocharger with variable nozzle turbine and exhaust gas recirculation. • Oxidizing catalytic converters to minimize emissions of carbon monoxide (CO) and unburned hydrocarbons (HC). • The particulate filter, fitted as standard in all Mercedes-Benz diesel cars in many countries since summer 2005, reduces particulate emissions by as much as 98 percent, thus easily undercutting even the current EU 4 particulate limits (0.025 g/km). This technology also ensures compliance with the US limits currently in force. • Nitrogen oxides – whose concentration is higher than in the exhaust gases of gasoline engines due to the specific combustion process in diesel engines – are reduced to such an extent that even the world's most stringent exhaust gas limits can be complied with. Here the so-called BLUETEC technology is utilised. This reduction is achieved either with an advanced DeNOx storage catalytic converter, available in the E 320 BLUETEC from autumn 2006, or with the more complex but even more effective AdBlue injection. This, combined with Selective Catalytic Reduction (SCR) creates the most effective method of exhaust gas after-treatment currently available. This enables nitrogen oxide levels to be reduced by up to 80 percent. The Mercedes Benz engineers will be show-casing the combination with AdBlue injection in the Vision GL 320 BLUETEC at the Detroit show and are developing the process for use as a standard system in passenger cars.

The SCR process is based on the injection of the reducing agent AdBlue into the exhaust gas stream. AdBlue is an aqueous urea solution that is carried in a separate tank. Since an average of around 0.1 liters per 100 km (2352.15 mpg or 1 to 3 percent of diesel consumption) is all that is required, the tank can be designed so that it only needs to be refilled when service staff are carrying out regular, scheduled maintenance. When AdBlue is injected into the pre-cleaned exhaust gas, ammonia (NH3) is released, causing the nitrogen oxides to be converted into harmless nitrogen (and water) in a downstream catalytic converter. The decisive factor in ensuring that the catalytic converter works extremely efficiently is precise metering in line with the current engine operating state. Choosing which technological solution to use depends both on the vehicle concept concerned and on the required "denoxing" rate.

BLUETEC already a success in commercial vehicles

However, BLUETEC technology is not altogether new as, in Europe, it has already been employed extremely effectively in Mercedes-Benz commercial vehicles with a GVW above six tonnes. This technology has proved a resounding success in more than 10,000 vehicles such as the Actros, Axor and Atego trucks. In this case, BLUETEC reduces the nitrogen oxide levels considerably, meaning that these vehicles already comply with the emission standards due to come into force for trucks from 2009. In Europe the AdBlue supply network already comprises some 1,500 filling points.

About the Author
Mike Hanlon After Editing or Managing over 50 print publications primarily in the role of a Magazine Doctor, Mike embraced the internet full-time in 1995 and became a "start-up all-rounder" – quite a few start-ups later, he founded Gizmag in 2002. Now he can write again.   All articles by Mike Hanlon
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