Volkswagen has just unveiled its cleanest TDI engine ever built. Powering the Jetta, this 2.0-liter common rail diesel mill can reduce nitrogen oxide (NOx)
emissions by 90 percent thanks to its reservoir catalytic converter. Production is expected to begin in the United States in 2008.
Volkswagen had to significantly raise the bar to comply with California's regulations, which limit NOx emissions to 70 mg per mile. In order to reach this magic mark, the German carmaker developed two systems connected to the oxidation catalytic converter and the particle filter in the exhaust system. The system is regularly and automatically cleaned without the driver noticing.
An ingenious technology
Larger and heavier models like the Passat feature the Selective Catalytic Reduction (SCR) catalytic converter. The central element is an aqueous solution called AdBlue (32.5 percent is comprised of urea), which is transported in an additional tank made from stainless steel or plastic. The solution is continuously injected into the exhaust system where it is finely atomized by a grille and converted into ammonia. The ammonia then reacts with the NOx in the catalytic converter and separates it into nitrogen and water. According to American regulations, the complete system must be fully functional for at least 150,000 miles.
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Volkswagen had to significantly raise the bar to comply with California's regulations, which limit NOx emissions to 70 mg per mile. In order to reach this magic mark, the German carmaker developed two systems connected to the oxidation catalytic converter and the particle filter in the exhaust system. The system is regularly and automatically cleaned without the driver noticing.
An ingenious technology
Larger and heavier models like the Passat feature the Selective Catalytic Reduction (SCR) catalytic converter. The central element is an aqueous solution called AdBlue (32.5 percent is comprised of urea), which is transported in an additional tank made from stainless steel or plastic. The solution is continuously injected into the exhaust system where it is finely atomized by a grille and converted into ammonia. The ammonia then reacts with the NOx in the catalytic converter and separates it into nitrogen and water. According to American regulations, the complete system must be fully functional for at least 150,000 miles.
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