An Investigation Of Fuel Spray Breakup Model Matching And Injection Parameters Study Of Heavy Duty Diesel Engines

Diesel engine became one of the most important devices for motive power machinery immediately after its birth for its high thermal efficiency, low emission of carbon monoxide, excellent durability and reliability. In recent years, with the tightening regulation of emissions in every country in the world, all industries are need for new power machines with better dynamic property and high economical efficiency, for which the technological development of diesel engine tends to make astounding advances. The experimental methods on the technical research of diesel engine induce higher reliability and practicability, while, the cost in time and economic are very high. With the development of Computational Fluid Dynamics (CFD), using professional computer programs to simulate the working process of engine has blazed a new way in engine’s scientific research.This paper focuses on the Caterpillar 3400 series engines which are the classical series in Caterpillar Company. The research and development of these series engines has accumulated a set of effective experimental data, leaving valuable experiences for later researchers. This paper constructed the combustion chamber and generated the calculation grid using the three-dimensional cartographic software- Pro/E and the ICEM (the integrated computer engineering) of ANSYS (a professional software of finite element analysis), respectively. The grid file, initial and boundary conditions’ file, and the detailed chemical reaction file were coupled into the KIVA-3 V, a three-dimensional calculation code of internal combustion engine, and then carried out the three-dimensional simulating calculation. The calculation data were processed and analyzed through a professional post-processing software, TECPLOT.Aim at verifying the effects of break-up model on the working process of diesel engine, this paper selected four different fuel spray orifices, which include 8 orifice and 225 micrometer for diameter of the orifice,8 orifice and 260 micrometer for the diameter,6 orifice and 260 for the diameter,6 orifice and 300 micrometer. These parameters of orifice were widely used in the’Kelvin-Helmholtz and Rayleigh Taylor’ break-up model (KH-RT) for matching and the results agreed with the experimental data very well, proving the reliability of engine’s three-dimensional simulating calculation.After the verification of break-up model, a sensitivity analysis has been further discussed which focuses on the effects caused by unsure parameters like the variable parameters in the break-up model, the initial condition, the boundary condition and the cone of spray. The paper investigated the incidence of in-cylinder pressure, brake specific fuel consumption, the emission of NOx and Soot caused by unsure parameters under different SOI (start of injection). Analyzed the effects of in-cylinder pressure, brake specific fuel consumption and the emission caused by different fuel spray strategies and EGR rates, that among these are the start of. main injection, the values of the pre-spray, the intervals between the pre-spray and the main spray and different EGR rates, based on a heavy diesel engine, which provides a new research orientation for optimizing the fuel’s injection parameters of the diesel engine.