Research to short combustion duration in diesel engine use of CNG fuel

Abstract

     Natural Gas has known as well as a great promising fuel and can be replaced petroleum in the sectors such as transport and agriculture. However, a big problem with natural gas as alternative fuel for internal combustion engines, which was slower burning speed in comparison with gasoline and diesel
fuels. This article was presented a simulation research on the effect of parameters such as bowl depth (Hb), spark plug position (OS), the position of center bowl in comparison with center cylinder (OB) and ignition timing (IT) on the combustion duration of diesel engine with using natural gas. The obtained
results from AVL Boost simulation at 1800 rpm have shown that the effect of bowl depth on the kinetic energy of gas flows into cylinder was very large. It is due to take full advantage of Squish velocity and the result in the turbulent velocity fluctuations were significantly increased in comparison with flat
piston head at nearly the end of compression stroke, especially. In order to reach the shortest combustion duration, the position of both spark plug and center bowl should be designed to center cylinder, in addition to the bowl depth is around Hb = 17.5 (mm) and ignition timing have to adjusted earlier than IT = 18o
before top dead center