Evaluate the influence of several parameters on the HCCI combustion process in a constant volume combustion chamber

The combustion process in a Homogeneous compression charge ignition (HCCI) engine is complex and determined by the dynamics of chemical reactions, while the combustion timing remains challenging to control. To control this process and expand the operating range of HCCI, it is necessary to change the compression ratio, adjust the opening/closing time of the intake and exhaust valves, and manage the temperature (including internal or external exhaust gas recirculation). This paper studies the effects of oxygen concentration in the intake air and ambient temperature inside the combustion chamber on the HCCI combustion process in a Constant Volume Combustion Chamber (CVCC) using 10% Biodiesel (B10) and conventional Diesel fuel (B0). The experimental results show that ambient temperature and oxygen concentration have a significant influence on the combustion process. Higher temperature and oxygen concentration increase the fuel–air mixing rate, reduce the ignition delay, and improve the combustion efficiency. It makes the heat release rate faster and the rise in pressure stronger. These results are essential for optimizing the combustion chamber design and operating parameters to improve engine performance while minimizing emissions.