Tuesday, September 23, 2008

Look toward the future – Crafter BlueMotion study with AdBlue technology




-Crafter BlueMotion with high roof consumes just 9.1 liters on average
-Concept car already fulfills Euro-5 standard thanks to SCR catalytic converter with AdBlue technology

In a world premiere, Volkswagen Commercial Vehicles is presenting the Crafter BlueMotion concept vehicle at the International Automobile Show in Hanover (September 25 to October 02). For the first time, the company has applied the pioneering economical BlueMotion concept to a high-roof van of the 3.5 tonne class. Powered by a 80 kW / 109 PS strong common rail turbo-diesel, the Crafter BlueMotion as a panel van with high roof and long wheelbase (4.33 meter) consumes just 9.1 liters diesel per 100 kilometers on average. This value represents a savings of 1.0 liter compared to the production version. Of course, the van with its high-tech diesel engine satisfies the Euro-5 emissions standard that becomes law in Fall 2009.

Compared to the production vehicle, CO2 emissions were reduced by 10 percent to 241 g/km. Engine developers were able to lower nitrogen oxide emissions (NOx) by 43 percent. Making a significant contribution here is the SCR catalytic converter with AdBlue technology being implemented in a Crafter for the first time.

The engineers and designers of Volkswagen Commercial Vehicles achieved these first-class fuel economy and emission values on two levels that merge under the BlueMotion badge. First level: aerodynamic optimization. Second and decisive level: high-tech powertrain and emissions control system. The concept car is also equipped with tire pressure monitoring and cruise control system, so that these parameters that have a significant impact on fuel economy can always be ideally calibrated too.

Furthermore, the engineers utilized regeneration – generation of electrical energy during braking – to reduce fuel consumption. Background: thanks to regeneration, battery recharging can be reduced in certain operating phases, or it may be deactivated entirely. Instead, the battery is efficiently recharged with “cost-free” braking energy in overrun operation. This specific energy management system saves on fuel. Use of a variable-control pump (VDP) for power steering also reduces fuel consumption.

The large frontal area of the Crafter’s structural design together with its high roof, made designers seek fine tuning in details. These details include a new radiator grille profile that gives the wind less surface area to catch hold of. In addition, a rear spoiler offers further aerodynamic improvements.

Modifications to the Crafter powertrain and a high-tech emissions control system had a crucial impact on the vehicle’s low fuel consumption and emission values and made it possible to decisively fulfill the Euro-5 standard.

Engine: Here Volkswagen Commercial Vehicles chose a common-rail five cylinder with 109 PS and 2,461 cm3 displacement. The production version of this 280 Newton-meter strong engine is paired with a 6-speed transmission and a diesel particulate filter as standard equipment. On the Crafter BlueMotion concept car, the engine – coupled to a rear axle with a high gear ratio (3.923:1, ECO axle) and a transmission optimized for fuel economy – is an engine version that was specially adapted, by internal
engine modifications, to a supplemental emission control system that utilizes a so-called SCR catalytic converter together with AdBlue technology.

The acronym SCR stands for “Selective Catalytic Reduction”, an internationally recognized term. “Selective” refers to the fact that this catalytic converter has a very special task: its purpose is to selectively convert nitrogen oxide (NOx) components of the exhaust gas to nitrogen and water without forming undesirable side products. It was developed precisely for this highly specialized task. Important: despite the SCR catalytic converter, in parallel the Crafter BlueMotion concept vehicle will be equipped with an oxidation catalytic converter and a diesel particulate filter.

Back to the SCR catalytic converter: conversion of the nitrogen oxides is accomplished by use of a synthetically produced, water-based urea solution by the name of AdBlue that is stored in an auxiliary tank on the Crafter. This substance consists of 32.5 percent urea and is continuously sprayed into the exhaust gas upstream of the SCR catalytic converter. It is metered according to the mass flow rate of the exhaust gas; engine management – informed by a NOx sensor downstream of the SCR catalytic converter – precisely controls the process.




Atomized into a fine vapor through a screen, the urea reacts in the SCR catalytic converter with the nitrogen oxides and splits them into nitrogen and water. The water-based AdBlue additive is nontoxic, odor-free and biodegradable.

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