Technologies for (pilot) injection quantity control in modern common rail diesel engines

Clean, powerful and efficient automobiles are the entry card into the automotive future. Unfortunately, simultaneously to the big progress in exhaust gas cleaning technology on the one side, more challenging testing cycles and also the focus on “customer usage conditions” do exist as challenging legal requirements on the other side. As a consequence, low engine out emissions still are important for the OEM and here the fuel injection system plays a substantial role.With the introduction of Common Rail technology the concept of “multiple injections” e.g. a mix of 1-5 pilot injections, up to 2 main injections and 1-3 post injections became a standard. Different to gasoline engines, were (global) λ-control covers a big portion of fuel injection control, diesel engines suffer from poor knowledge on the real injection pattern – that is the precise and physical correct split of the injections.