Effect of the geometrical shapes of the helical-spiral shroud intake valve on swirl generation in cylinder of diesel engine

Abstract

Improving combustion efficiency for diesel engines is an important requirement to save fuel and lower exhaust gas toxicity. In this study, the effect of the geometric shape of the helical-spiral shroud intake valve (HSSIV) for the swirl generation in a diesel engine cylinder was studied, which has important significance in improving the combustion efficiency in a diesel engine.In this study, helical-spiral shroud (HSS) are classified into convex, flat, and concave types according to the installation angle on the intake valve, and their influence on the swirl generation in the cylinder are comparatively analyzed using the computational fluid dynamics (CFD) method. As a result, it is considered that HSSIV with convex shape generates the best swirl and tumble effect in the engine cylinder. The Model 1 with convex shape has a swirl ratio value of 32.5 which is 3.8 times larger at 80CAD, and the tumble ratio value is 48.2 which is 4.5 times larger at 130CAD, compared to Model 0 with no shroud. The findings and results of this study were applied to the diesel engine, but they can also be applied to gasoline engines, and can also be applied to research subjects that need to generate a swirl in the fluid flow path without additional energy consumption and reduction in the volumetric efficiency of the fluid.