Analysis For Influence Of Combustion Chamber Geometry On Performance Of Model 170 Diesel Engine

It is shown that combustion chamber shape has evident effects on burning rate and preventing abnormal burning. Many measures of improving burning are used in the combustion chamber. Design of combustion chamber shape deeply influence on smoke. It is study that influence of combustion chamber geometry on performance of model 170 diesel engine. In primarily, it is shown that theory by diesel engine performance tests in test bed. Smoke and performance can be improved effectively by design of the combustion chamber. Dynamic simulation is carried out to study the transient intake and in-cylinder flow generated during intake and compression strokes using with the FIRE software from AVL company in Austria.Well convergent results show formation and development of swirl, squish, tumble and turbulence. In-cylinder flow generated during intake stroke is disorganized at the beginning, and then it develops into a large number of small-scale swirls, which develop into a single stable large-scale swirl at the later half of intake stroke. At the beginning of compression stroke, intake swirl is maintained and compression swirl is generated, while at the end squish comes into being when helical flow moves from cylinder to combustion chamber. At the same time, in-cylinder tumble is strengthened gradually. With the increase of crank angle, the mean kinetic energy of in-cylinder turbulence during compression stroke decreases at first, then increases and finally decreases again. At the end of compression stroke, the turbulent kinetic energy of flow around the edge of cylinder is weak, while that of squish in the middle is relatively strong. Horizontal swirl, axial tumble and the distribution of turbulent kinetic energy are very important for fuel atomization and mixture formation.