Numerical Study of Emissions on DDF Engine with 20% CNG with Variation on Compression Ratio

The increasing of shipping transportation has an impact on the survival of living things on earth. The data shows that there is a tendency to increase the contribution of higher emissions. It has led to the birth of increasingly stringent and binding regulations; on the other hand, the limited availability of liquid fossil fuels encourages prices to continue to soar and leads to increased operating costs. Modifying diesel to dual fuel and utilizing natural gas as the main fuel arealternatives to overcome this problem. Changing the diesel engine to dual fuel is relatively easy and cheap, and using natural gas, which has cleaner emissions and more abundant availability, makes it better for the environment. By converting diesel to dual fuel, it is necessary to adjust both the design and operational parameters of the engine, one of which is the compression ratio. In this study, numerical tests on dual-fuel engines with various compression ratios of 16, 18, and 19 at 20% CNG and 80% diesel fuel at a constant speed of 2000 rpm get the results of exhaust emissions under these conditions. The results show that a high compression ratio gives a more significant UHC reduction value in CNG with a low ratio decrease in UHC by 50–56% at 0% CNG and decrease by 39–46% at 20% CNG.