PistenBully-News team: Mr Kuhn, at the Interalpin 2013, the Kässbohrer Geländefahrzeug AG presented the PistenBully 600 SCR. What does SCR stand for?
Michael Kuhn: SCR means selective catalytic reduction. This is a method of exhaust gas aftertreatment for diesel engines which helps us to reach the limit values for the Tier 4i emission level.
PistenBully-News team: Could you please tell us how this method works?
Michael Kuhn: Among others, exhaust gas also contains nitrogen oxides (NOx). With the selective catalytic reduction, we use a catalytic converter in which the nitrogen oxides are reduced under the effect of AdBlue®. As a result, the exhaust gas then only contains N2 as pure nitrogen. This is a natural component of air. Thus, through the influence of AdBlue®, NOx turns into pure nitrogen and water vapour.
PistenBully-News team: The system wouldn't work without AdBlue®?
Michael Kuhn: That's correct. AdBlue® is a watery urea solution and the reactant with which the exhaust gas is purified in a multistage process in the SCR catalytic converter.
PistenBully-News team: And when you run out of AdBlue®? What will happen then?
Michael Kuhn: First the PistenBully will continue to run in its regular mode. However, the legislators have stipulated measures for this case. An on-board diagnosis device takes care that the emission values of the engine are actually adhered to. Should the vehicle run without the addition of AdBlue® for a longer period of time, the engine performance will be reduced step by step to make the driver refill it with AdBlue®.
PistenBully-News team: So that means that you as the manufacturer actually assume the responsibility that the emission standards are adhered to?
Michael Kuhn: Right, that is a topic that the legislators have decided this way to prevent misuse. We as the manufacturers are obliged to implement the legal stipulations.
PistenBully-News team: So in other words if the operator still tries to go without the AdBlue®, he has to live with the consequence that the vehicles run at a lower performance rate?
Michael Kuhn: Yes, the power reduction is actually that strong that the operation finally even becomes impossible. ?
PistenBully-News team: The introduction of the next emission standard Tier 4 final is just around the corner. When exactly will it be introduced? And which consequences will it have?
Michael Kuhn: The next emission level, Tier 4f, will become effective on 1 January 2014. It will then become necessary to comply with even stricter emission standards. In order to fulfil Tier 4 final, the exhaust gas aftertreatment systems have to be extended once again. Depending on the engine type and the performance class, additionally there will be an exhaust gas recirculation inside the engine, an oxidation catalytic converter and/or a particulate filter. But this will always be based on the SCR system. From 2014 on, it will be principally impossible to carry out the exhaust gas aftertreatment without AdBlue® since the strict emission limits can only be achieved with AdBlue®.
PistenBully-News team: What does this imply for the Kässbohrer Geländefahrzeug AG and its customers?
Michael Kuhn: We are optimally prepared for the introduction of Tier 4i and we will promote the further development of the vehicles towards Tier 4 final. Those customers who with their infrastructure already today pave the way for Tier 4i and thus for AdBlue® will be well prepared for the future.
PistenBully-News team: So that means that also in the future, engine technology will be clearly determined by exhaust gas purification and the addition of AdBlue®?
Michael Kuhn: Yes, exactly!
PistenBully-News team: Thank you very much for this informative talk.