FOR 2401

Policy makers have set external page ambitious goals to further increase the thermal efficiency of internal combustion engines, since they are still an important technology for heavy-duty applications.

A possible approach to further improve compression-ignited engines is PCCI-combustion. This type of combustion shows great potential in further increasing thermal efficiency while at the same time lower engine-out pollutant emissions.

In contrast to conventional compression-ignited engines, the PCCI-process has a high sensitivity to the initial conditions in each cylinder. Feedforward control is no longer sufficient to ensure a stable combustion and hence feedback control of the combustion and air path is required. The controller must obtain an appropriate control signal for each engine cycle based on the cylinder-pressure of the previous cycle. This requires extremely fast computing times and is a difficult task due to the already existing complexity of the engine.

The knowledge gained from this research project is manifold. Firstly, the variable valve train can further improve the fuel consumption of conventional Diesel engines. Secondly, the valve train enables large control of the sensitive PCCI-combustion. Thirdly, the control system in combination with the novel valve train will be used to develop concepts for combustion control, with which the combustion process can be greatly influenced. This creates the possibility to consider the fuel as a further degree of freedom. With regard to the increasing use of regenerative fuels, the ability of an engine to adapt to different types of fuel and to burn them as efficiently as possible is of utmost interest.