What is a PCCI engine

Regulation of the partially homogenized combustion in the compression-ignition engine

The most challenging part of the engine combustion development is the reduction of pollutants (e.g. CO-, THC-, NOX-, soot-, etc.) and CO2emissions. Therefore new combustion techniques are required to enable a clean efficient combustion. For compression ignition engines two technologies are the focus of our work. The first is the so called rate shaping. With multipe injection events the energy conversion inside the combustion chamber can be manipulted in order the influence of the efficiency and the emission formation for the high temperature combustion (HTC) close to the top dead center (TDC). The other concept is the low temperature combustion (LTC). Early injection events are used together with high amounts of exhaust gas recirculation (EGR) in order to extend the ignition delay. This enables a partly partly premixed compression ignition (PCCI) which is controlled by a later main injection. Both technologies have different benefits and disadvantages.

Our work will focus on developing a combustion and controller models to combine both technologies to take the highest benefit from both processes. Figure 1 shows a scheme of the combustion controller. The low temperature combustion and the pressure trace of the high temperature combustion will be predifined. By manipulting the injection events the model predict the combustion and apply this to the engine test bench. In-cylinder pressure sensors are used in order to focus the control of the HTC. An additonional sensor will be mounted inside the combustion chamber in order to analyze the LTC enabled with PCCI.

The project is part of the research group FOR2401 which focus on "Optimization-based multi-scale control of low-temperature engine combustion processes" sponsored by the DFG (German Research Foundation).