Volkswagen introduced its cleanest TDI engine. Initial tests conducted by VW have already shown promising results when the TDI engine succeeded in reducing nitrous oxide. For the Volkswagen Jetta, a new 2.0-liter commo9n rail diesel engine is used with a nitrogen oxide catalytic converter tank that meets the California Tier 2 / Bin 5 emission standard. – considered to be the most severe in the world. The first generation of TDI with a nitrogen system will be made in 2008 in the United States.
The main purpose of the TDI engine is to reduce emissions of nitric oxide. Volkswagen's Volkswagen Engineers team is working on engine development and the use of new post-processing technology. They have already achieved 90% less emissions of nitrogen oxides.
This drastic reduction is required to meet the Tier 2 / Bin 5 standard that applies to California and four other northeastern states: Massachusetts, New York, Vermont and Maine. — This norm limits NOx emissions to 70mg per mile. To comply with this standard, VW has decided to develop an entirely new emission cleanup technology.
Volkswagen has been able to develop two new systems linked to the oxidation catalytic converter and the particulate filter in the exhaust system. The new Nox catalytic converter technology of the tank is currently tested for Passat class cars. Nitrogen oxide is absorbed as a sponge, resulting in a high level of efficiency. As for the particulate filter, the system is cleaned regularly without the driver being aware of it. How? The engine management system changes the operating modes for a few seconds.
For the larger and heavier Volkswagen models, they will have a catalytic converter for selective catalytic reduction (SCR). The central component of SCR is an aqueous solution such as AdBlue, which is transported in an extra tank made of stainless steel or plastic. The aqueous solution also consists of 32.5% urea, which is continuously injected into the exhaust system in front of the SCR catalyst by means of a metering valve. The amount of the aqueous solution is obtained according to the flow of gas emissions.
The solution of urea, which is mixed with the aqueous solution, is gently sprayed onto the grid and converted to hot exhaust gas in ammonia before it reaches the catalytic converter. Ammonia then reacts with the nitrogen oxide in the catalytic converter and is separated into water and nitrogen.
The ammonia produced is not like ordinary ammonia in the sense that it is non-toxic, odorless and biodegradable. Volkswagen also intends to install the extra tank so that the car can be operated without any need for maintenance between the workshops. According to the US regulations, the whole system should operate at least 150,000 miles.