Numerical Simulation Of The Combustion Process For A Spray And Wall Complex Guided Of LPG DI Turbocharged Engine

In recent years, people’s living standards continue to improve, the popularity of the car has also led to the rapid development of the automobile industry, but also bring a series of problems such as energy shortage and environmental pollution. So people began to try to find a new alternative energy vehicles, liquefied petroleum gas (LPG) is one of the most representative of the new energy. t has the advantages of convenient storage and transportation, high octane number, low emission of harmful pollutants and other traditional fuels can not be compared. The paper adopts the spray and wall complex guided combustion system proposed by our research group, numerical simulate of the homogeneous combustion process under high load conditions than combustion and lean combustion process under partial load condition.The paper establishes a double intake port and single inlet dynamic mesh model using AVL FIRE software to simulate the engine under different working conditions of the gas mixture formation and combustion process. In the process of calculation, we need to put the chemical kinetic mechanism of LPG in the FIRE software. If directly to the detailed chemical kinetic reaction mechanism and AVL fire software coupling to numerical simulation of computer configuration and high cost of long computing time. In this paper, the detailed chemical kinetic mechanism was simplified to eventually contain a simplified model for a group of 32 points and 69 a chemical reaction, and its effectiveness was verified.The mixture formation and combustion process of the homogeneous combustion under high load condition and the stratified lean combustion under partial load conditions were simulated. The results show that when the fuel injection timing is 70℃ A ATDC, the better homogeneous mixture can be formed in the cylinder. By selecting different ignition timing to study the combustion process results indicate, when the ignition timing is 25℃A BTDC the combustion characteristics are best but NO and CO emissions increased, the corresponding phase angle near the ATDC 5～15℃A Numerical simulation of stratified lean combustion process under partial load conditions of a single intake and four stroke LPG engine. In the stratified combustion mode, the fuel injection timing is set up to 40℃A BTDC, which can form a better stratified mixture.Then when the engine speed is 2000r/min and 3000r/min in two cases of different ignition time of the combustion process are analyzed. When the engine speed is 3000r/min LPG engine in the exothermic combustion process in cylinder and the rate of peak peak pressure is higher and less CO emissions, has better combustion characteristics, but the NO emissions increased.