Scania will start introducing its new engine platform for Euro 5 during 2007. On these new engines, Scania uses EGR (exhaust gas recirculation) without any aftertreatment to meet Euro 5 emissions requirements.
This technology does not require the driver/operator to handle any additives (i.e., AdBlue for SCR) when refuelling and no extra installations are needed on the vehicle.
During 2007 Scania will start introducing a new range of Euro 5 engines with EGR and with the new Scania XPI common-rail fuel injection system, starting in the mainstream long-haulage segment.
The new engines meet Euro 5 without any fuel penalty.—Hasse Johansson, Scania Group Vice President Research and Development
Scania introduced its first Euro 4 engines using EGR technology two years ago. Scania has since introduced a range of Euro 4 and Euro 5 engines using both EGR and SCR (selective catalytic reduction). (Earlier post.)
Scania EGR reduces the combustion temperature by recirculating a portion of the exhaust flow—up to 18% for Euro 4 and 25% for Euro 5—before the turbocharger and cooling it with the engine coolant before blending with the intake air, which in turn reduces the formation of nitrogen oxides (NOx).
The challenge consists in feeding exhaust gases into the intake air, which has a higher pressure. Scania has solved this with a patented venturi system. The Scania venturi is a constriction in the intake manifold that makes the compressed intake air travel faster. This creates a low-pressure area downstream of the constriction, which is used to suck the exhaust gases into the intake air. A simple valve system is used to regulate the flow in relation to engine load.
The engines use high-pressure fuel injection in combination with a maintenance-free oxidizing catalyst to reduces particulates and eliminates the diesel smell.