Diesel is a petroleum-based fuel that contains higher energy content than gasoline. This greater energy content, coupled with the efficiency of compression ignition, explains why diesel vehicles get better gas mileage. Diesel fuel vehicles deliver 20 to 40 percent better fuel economy than their gasoline counterparts.

Clean diesel is an evolutionary systems-based process that combines advancements in diesel engines, cleaner burning fuels, and emissions control systems, all working and optimized together. State-of-the-art engines, cleaner-burning fuels, such as ultra-low sulfur diesel fuel (ULSD), and effective emissions-control systems are the three pillars of clean diesel technology. ULSD is a refined diesel fuel that has much lower sulfur content compared to regular diesel fuel, resulting in dramatic diesel emission reductions. ULSD is required for the precise engine and advanced exhaust treatment technology of all MY08 diesel vehicles: E320 BLUETEC Luxury Sedans, ML320 CDI SUVs, GL320 CDI SUVs, and R320 CDI SUVs.

Common-rail Direct Injection. CDI is a fuel-injection system that maintains a constant level of high fuel pressure (according to speed and throttle) in each of the engine's six injector valves. With the precision to control several stages of injection with each cylinder stroke, fuel injection using the CDI system softens diesel "power pulses," resulting in smoother, quieter, and more powerful performance with cleaner emissions.

The third generation of CDI technology is incorporated into the latest Mercedes-Benz V-6 diesel engine, featured in the E320 BLUETEC Luxury Sedan, ML320 CDI SUV, GL320 CDI SUV, and R320 CDI SUV. The V-6 diesel engine uses the most advanced diesel engine technology. This includes four valves per cylinder, the third-generation CDI system with state-of-the-art piezoelectric fuel injectors, and a turbocharger with Variable Nozzle Turbine (VNT) and exhaust gas recirculation. This diesel engine is smoother, more efficient, and more compact — yet also more robust and powerful than the inline-6-cylinder diesel engine that it replaces.

Extensive development work has made this a surprisingly quiet engine. Thanks to new technology mentioned above, pilot injection — a small quantity just before the primary injection — softens the pulse of diesel combustion. Also, the engine block is contoured to minimize noise. These features make the engine smoother, more efficient, and more compact — yet also more robust and powerful than the inline-6-cylinder diesel engine that it replaces.

BLUETEC incorporates additional emissions control technology. An advanced DeNOx (nitrogen-oxide-reducing) storage catalytic converter and a selective catalytic reduction (SCR) catalytic converter work together with the standard oxidizing catalytic converter and particulate filter to further reduce regulated emissions.

To meet even more stringent emissions requirements, the BLUETEC system could be equipped with another module — AdBlue injection, replacing the DeNOx storage catalytic converter. A water-based urea solution, AdBlue is carried in its own tank and metered into the exhaust in minute quantities — quantities so small that the tank only needs to be refilled during routinely scheduled maintenance. When AdBlue is injected into pre-cleaned exhaust gas, ammonia (NH3) is released, converting nitrogen oxides into harmless nitrogen (and water) in the downstream SCR catalytic converter. Called SCR for selective catalytic reduction, this process creates the most effective method of diesel exhaust gas after-treatment currently available. In Europe, AdBlue injection has already proven effective in more than 15,000 Mercedes-Benz commercial vehicles.

Diesel engines have long been recognized as an affordable technology capable of delivering superior fuel economy in both city and highway driving. While in stop-and-go traffic, hybrids often run on battery power and are most efficient while driving in a city, and typically have a significant price premium over their gasoline counterparts.

A recent comparative test drive showed that the advanced diesel engine can be more efficient than the hybrid over a long drive. The test drive, conducted by Auto Bild magazine, compared the performance of two Mercedes-Benz ML320 CDI (European specification) vehicles and a Lexus RX 400h with a gasoline hybrid system on a drive across the U.S., from the east coast to the west coast. Click here to read the full press release.

There are approximately 55,000 diesel stations in the U.S. — nearly one of every three gas stations across the country. You can find them with a touch of your i-button. Eighty percent of U.S. diesel fueling stations will supply the ultra-low sulfur diesel fuel required by the CDI and BLUETEC models as of mid-October 2006, as required by the U.S. government.

Mercedes-Benz USA now approves the use of B5 bio diesel (standard automotive diesel with maximum five percent bio diesel content) in all Common Rail Direct Injection Diesel (CDI) engines. As bio diesel can be refined from a variety of raw materials resulting in widely varying properties, the only approved bio diesel content is one that meets ASTM D6751 specification and that has additionally the necessary oxidation stability (min. 6h, proved with EN14112 method) to prevent damages to the system from deposits and/or corrosion.

Please ask your service station for further information. If the B5 bio diesel blend is not sufficiently labeled to clearly indicate that it meets the above standards, please do not use it. The Mercedes-Benz Limited Warranty does not cover damage caused by the use of fuels not meeting Mercedes-Benz approved fuel standards.

E85 is composed of 85 percent ethyl alcohol (ethanol) and just 15 percent petroleum. E85 is designed for use in Flexible Fuel Vehicles, referred to as FFVs. FFVs may fuel with either E85 and/or gasoline interchangeably. Most FFVs are still fueled with gasoline, but the availability of E85 and FFVs is expected to increase in the next few years. Model Year 2003-05 C320 Sedans/Wagons/Coupes (non-4MATIC), Model Year 2004-05 C240 Sedans/Wagons (non-4MATIC), and the Model Year 2007 C230 Sport Sedans are E85 compatible.

Fuel cell technology produces electricity and heat through controlled, electrochemical reactions in the fuel cell between hydrogen and oxygen, with water being released as a by-product. Efficiently harnessed, this energy can be utilized to drive vehicles via an electric motor. Stacking one fuel cell behind the other, enough power is generated to drive the vehicle, as well as to provide power for the numerous electrical applications in the vehicle, such as air conditioning systems, additional safety functions, or mobile office applications.

There are currently approximately 30 Mercedes-Benz F-Cell test vehicles undergoing real-world testing in the U.S. These cars are part of DaimlerChrysler's 100+ Fuel Cell demonstration fleet, which include transit buses and Sprinter vans. These vehicles emit no harmful emissions; water is the only by-product and emission. It is currently expected that the first series-produced models will be available between 2012 and 2015.