|The Touareg BlueTDI.|
Volkswagen chose Geneva as the venue to unveil its new Touareg BlueTDI SUV with a urea SCR (Selective Catalytic Reduction) system which meets the US Tier 2 Bin 5 NOx limit of 0.07 g/mi (0.043 g/km). The Euro 4 standard currently in force in Europe specifies a NOx limit of 0.25 g/km.
The 3.0-liter, 164 kW (220 hp) Touareg BlueTDI will join a Tier 2 Bin 5-compliant version of the Jetta to enter the market in all 50 states in the US in 2008. The Jetta will use a lean NOx trap rather than urea SCR. (Earlier post.) The two systems will debut in Europe a short time later, according to Volkswagen.
The SCR system in the Touareg uses an aqueous urea solution (AdBlue) stored in an auxiliary tank. The Touareg BlueTDI is also equipped with an oxidation catalytic converter and a diesel particulate filter.
AdBlue is consumed at an average rate of about 0.1 liter per 100 kilometers. Consumption and tank size are sized so that the AdBlue supply does not need to be replenished until the next scheduled service.
Besides introducing the SCR catalytic converter, the engineers at Volkswagen Automotive Group used a number of modifications to the V-6 engine in the Touareg BlueTDI to reduce engine-out emissions.
Combustion chamber sensors integrated in the glow plug monitor pressure conditions in each cylinder and report the data to engine management. This enables optimized control of injection and combustion in each cylinder; it is even possible to compensate for fluctuating qualities of fuel. This helps reduce raw emissions and optimizes smooth running and noise behavior.
The common rail injection system features a newly designed pump that builds up 2,000 bar of pressure. The piezo injectors feature smaller eight-hole nozzles that inject miniscule spray volumes into the combustion chambers. Together with the higher pressure, this produces an injection that is precise and dynamic.
Exhaust gas recirculation (EGR) lowers maximum temperatures in the combustion chambers and to reduces oxygen concentration, reducing the NOx emissions. Remaining NOx flows to the SCR catalytic converter for reduction.
Volkswagen staged a number of other diesel world premiers at Geneva, including:
The new Passat BlueMotion with fuel consumption of 5.1 liters/100km (46 mpg US) and CO2 emissions of 136 g/km.
The new Golf Variant. As a TDI diesel with 77 kW (103 hp) it consumes just 5.2 liters of diesel per 100 kilometers (45.2 mpg US) with CO2 emissions of 137 g/km.
New Phaeton V6 TDI. This 171 kW (230 hp) luxury sedan meets the Euro-5 standards that go into effect in 2009.