Study Of High Pressure Air Jet Controlled Compression Ignition On Diesel Pre-mixture

With the progress and development of industry, energy issues are more and more important currently. People have improved their consciousness of environmental protection. A new combustion concept called homogeneous charge compression ignition has been proposed to satisfy the high efficiency and low emission requirements in internal combustion engines.To achieve the precise control of premixed compression ignition combustion, high pressure air jet controlled compression ignition (JCCI) on diesel pre-mixture has been proposed. By adjusting the effective compression ratio, the decrease of the temperature and pressure at the end of compression ensures that the auto-ignition of the pre-mixture cannot occur. Near the top dead center, a certain amount of high pressure air is jetted into the cylinder, and mixes with original mixture in cylinder. The original mixture in the local region is compressed by the high pressure air, and the temperature and pressure rise up immediately to satisfy the auto-ignition conditions, thus the precise combustion phasing control for diesel pre-mixture is realized consequently.In this paper, the effects of high pressure air jet parameters and check valve outlet diameter on the maximum temperature rising in the constant volume combustion chamber (CVCC) were studied by using numerical simulation method. The main work in this paper is to establish the model of CVCC and simulate the air jet process with 3-D CFD software. The temperature and pressure in the CVCC impacted by high pressure air jet impingement were analyzed. The simulation results indicate that temperature in the local region rises up immediately by high pressure air jet impingement in the CVCC. The maximum temperature rising is higher with the increase of jet temperature and pressure and the check valve outlet diameter. According to the simulation results, the experimental system was designed based on the optimized parameters.