584 / 2019-01-19 14:53:59

Study on Combustion and Emission Control Strategy of Biodiesel Fueled by Agricultural Machinery Diesel Engine in High Cold Environment

Biodiesel；Numerical Simulation；Combustion control；Emission control； Off-board purification

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With the rapid development of the automotive industry,the two problems of energy shortage and environmental pollution will be prominent.While controlling the pollution of automobile exhausts emissions,the process of urbanization and agricultural mechanization construction in China has accelerated,resulting in a significant increase in the use of diesel engines.To the harsh working conditions of agricultural machinery and the heavy load,the problem of exhaust pollution to the atmosphere has received increasing attention.
Biodiesel is a typical renewable fuel.Its combustion and emission control on diesel engines has become a hot research topic at home and abroad.China has vast land and abundant biodiesel resources,which limits its promotion due to high NOx emissions.China's terrain ladder is high in the west and lower in the east.China's terrain ladder is high in the west and lower in the east.The plateau region accounts for 1/3 of the country's land area. As the altitude increases,atmospheric oxygen content,air density,and Atmosphere pressure are getting lower and lower.Thus, it is necessary to study the use of biodiesel for agricultural machinery diesel engines to satisfy national IV and above emission standards under the condition of not changing the diesel engine body.It is not only an urgent demand for social development,but also a need for environmental protection regulations and the development of renewable energy combustion technology.This paper selects the altitude of 0 meters,1000 meters,2500 meters and 4000 meters as the research object,mixing 0# diesel and the biodiesel according to different volume fractions.Through mathematical modeling,the physical and chemical properties are calculated,and the appropriate physical and chemical property ratio interval is found.According to the physical and chemical properties of biodiesel and the climatic characteristics of the Inner Mongolia Plateau,the three-dimensional software PRO/E is used to draw the combustion chamber of an agricultural mechanical diesel engine, combined with EGR technology,and the grid is generated by the three-dimensional CFD software CONVERGE.The combustion process of the diesel engine was simulated with CONVERGE,boundary conditions,initial conditions and other calculation parameters defined to determine the turbulence model, combust the correctness of the model is verified and numerical simulation studied are carried out to establish a dynamic adaptive control model including combustion control and off-board purification. Secondly,the established dynamic adaptive control model is modified by experimental data to clarify the dynamic adaptive control mechanism of high altitude biodiesel combustion and emissions.Finally,the national IV diesel engine burns biodiesel to satisfy the limits of the national IV and above standards.