Why Iveco decided to adopt the SCR system
The SCR system chosen by Iveco represents the ideal compromise between two fundamental objectives engine designers had set themselves in order to meet customer requirements. On the one hand, improve engine performance to reduce fuel consumption and running costs, at the same time extending the life of engine components; on the other, comply with emission limits established by European authorities to safeguard the environment. Clearly, the progressive reduction in fuel consumption per tonne of goods transported means engines give off less CO2, the gas responsible for warming the planet.
Iveco began studies on SCR reduction in 1994 at its Arbon Research and Development Centre in Switzerland (Iveco Motoren Vorschung) as a member of a consortium created together with other manufacturers. Iveco has also explored the EGR solution and adopted it on the light commercial vehicle range, given that for this type of use it represents the ideal compromise between various factors (consumption, weight, cost).
Given the high average annual kilometres travelled by medium and heavy vehicles, the benefit obtained by reducing fuel consumption became the top priority. Furthermore, the SCR approach has no negative effect on lubricant quality or the interval between oil changes. In fact the low particulate content in the combustion chamber further extends these intervals. Similarly, the system isn't sensitive to the sulphur content of diesel fuel.
Unlike EGR technology the SCR approach doesn't require increased use of the engine cooling system. Everyone knows that high powered vehicles need larger radiators and the size of these poses serious layout problems on heavy vehicles. Also, increasing fan performance drains power and negatively affects fuel consumption.