Simulation Research On Combustion And Emissions Characteristics Of An Intake Air Hydrogen-added And DME-added Diesel Engine

Intake-air composition design is an important way to achieve clean and high-effici ency combustion of diesel engine, it can improve the combustion of engines and redu ce the fuel consumption and emissions simultaneously. The three dimensional simulatio-n program KIVA-3V was used in this paper to research the combustion and emission characteristics of a single cylinder135diesel engine, and the hydrogen and DME were added to the engine intake-air composition respectively.The simulation results of hydrogen added case showed that the ignition timing advanced, the rise rate and the peak of the cylinder temperature and pressure increased with the rise of hydrogen concentration, the formation time of Soot and CO advanced, the production increased firstly and then decreased, but the emission of NOx increased. And the combustion and emission characteristics of engine under different CO2mass fraction was researched under different CO2mass fraction based on the hydrogen rate of0.4case. It showed that the NOx decreased91.3%and the Soot decreased29.9%compared with pure diesel engine.The simulation of DME added case was also carried out, and the results showed that as the hydrogen concentration rose, the ignition timing advanced, the peak of the cylinder temperature and pressure increased and came early, the Soot decreased while the NOx increased significantly, the CO increased firstly and then decreased. And the combustion and emission characteristics of engine under different CO2mass fraction was researched under different CO2mass fraction based on the DME rate of0.4case. The NOx was founded decreased92%and the Soot was little compared with pure diesel engine.This paper researched the influence of intake-air composition added high-octane fuel (hydrogen) and high-cetane fuel (DME) on the combustion and emission characteristics of diesel engines, and reduced the emission of NOx and Soot simultaneously through the optimization of intake-air. It provides us with theoretical guidance for our future experiment research.