Development of control algorithm for an HCCI (homogeneous charge compression ignition) engine

In HCCI engines, the air-fuel mixture is taken into the cylinder homogeneously. The air-fuel mixture, whose pressure and temperature rises in the cylinder, self ignites simultaneously in all parts of the cylinder. Combustion initiation in HCCI engines depends on many parameters such as inlet air temperature, air-fuel ratio and chemical properties of the fuel. For this reason, control algorithms are needed for HCCI engines where all parameters that have a direct or indirect effect on combustion can be controlled in a unique way. This study was conducted for the development of control algorithms in HCCI engines. For this, an experimental setup was prepared with a spark-ignition single-cylinder 2.8 kW generator engine. Cam, crank, pressure sensors, electronic throttle, electronic ignition system and port type fuel injection system have been added to the engine. Inlet air heater has been manufactured so that the engine can operate in HCCI mode. In order to measure the engine load, a load cell is connected to the generator connected to the engine. In order to test the engine at different loads, a 3.0 kW resistance load circuit has been produced that can absorb the electricity produced in the generator. A control panel has been developed for flexible control of experimental parameters. A graphical user interface program was developed with the Matlab Appdesigner program in order to monitor and control the experiment parameters. The crank angle was measured precisely by calculating the time between the signals obtained from the crank sensor and the two crank angles. With the developed algorithm, the time required for any crank angle or the crank angle at the end of any time could be determined precisely. In this way, the injection and ignition systems could be precisely controlled.