One could say that Mercedes-Benz is getting into some funny stuff. I mean what else would you think if you heard that in the new Mercedes you bought, that they are putting urea (human waste) into your exhaust- personally I'd freak. Well to freak or not to freak they are doing it regardless, in four new Mercedes-Benz vehicles, 1 car and 3 SUV's. These four new cars will meet all of the new 8 emission standards for 45 of the United States, and the 2009 models will meet the 5 emission laws placed by the other five states basically making them available in all 50 states.
The system in these cars that is making this "gross" technology possible is called the Ad-Blue System, which is used in conjunction with a v-6 diesel engine. What the system does, is it adds pre-measured amounts of the urea based compound into the exhaust that is emitted from your cars exhaust pipe. When the diluted solution is injection into the exhaust stream it gets mixed with the heat of the exhaust causing the Nitrogen Oxide and Urea to reform as a harmless plain old Nitrogen.
The Ad-Blue solution is kept on board your vehicle in a tank, (hopefully a tank that doesn't leak, that would be gross). The Urea tank holds about seven gallons of the stuff and then at every 10,000 mile oil change the stuff gets re-filled at the Mercedes-Benz service station. This is to be comparable to that of diesel, if you were to run the tank dry, a counter on the car would let it start 20 times before refusing to run. To get a Mercedes with the Ad-Blue system it will be an added cost of $1500 dollars over the regular gasoline vehicle, but you will get 20-30 percent better fuel economy on the car. Sweet, its an environmentally friendly pee car, i want a pee car. "Hey how does your exhaust stay so clean? Well interesting you should ask, i just mix urea aka pee into it, to neutralize the harmful effects." "No way, can i pee on my exhaust too? "Nope, only Mercedes-Benz service stations can."
So the European car companies started this trend of Ad-Blue (Eu-ro-pee-in)(ha), anyways they are putting it in their vehicles that have larger diesel engines examples including the Mercedes-Benz ML320 BlueTEC, and the BMWX5 xDrive35d (both are SUV's, though)