INVESTIGATION OF GUIDE VANE SWIRL AND TUMBLE DEVICE TO IMPROVE IN-CYLINDER AIR FLOW FOR COMPRESSION IGNITION ENGINE RUNNING WITH BIODIESEL

Abstract

Biodiesel is expected to become the main alternative fuel for transportation purposes in the coming future as a result of the recession of crude oil. The main advantage that makes biodiesel the first choice as a substitute for petroleum-based fuel is that biodiesel can be used in a compression ignition engine (CI) with minor modification. Unfortunately, with biodiesel, the engine experiences reductions in power and torque, and increases in fuel consumption and carbon deposits inside the combustion chamber mainly due to lower calorific value and heavier molecules present in the biodiesel. One of the solutions to minimize this problem is to increase the in-cylinder air motion and use this to break up the heavier molecules and mix these molecules with air. To achieve this, a high turbulent flow is required inside the cylinder. This paper presents the model of the Guide Vane Swirl and Tumble Device (GVSTD) to develop an organized in-cylinder turbulent flow. The basic model of GVSTD consists of simple fins imposed inside the intake system. Through computer simulations, the results of air flow characteristics are compared with a conventional intake system. The height of GVSTD vanes was varied at 25%, 50% and 75% of the intake runner radius. The results show that in-cylinder velocity, turbulence kinetic energy and absolute pressure at the start of the injection increase around 41%, 6% and 3%, respectively more than the ordinary system which is expected to improve the mixing of biodiesel and air resulting in better combustion.