Experimental investigation of the combustion performance and emissions behavior of a lpg RCCI engine fueled with a mixture of diethyl ether and safflower oil biodiesel

Due to the significant increase in the number of vehicles in recent years, the demand for and supply of gasoline and diesel fuel has become unbalanced. If this situation continues, the cost of gasoline and diesel will increase and access to fuels will be insufficient. Today, the need for balancing the increasing energy demands continues. With the increase and depletion of fossil fuels, alternative fuels gain more importance. In this respect, the processed form of vegetable oil (biodiesel) constitutes a potential alternative for diesel engines. In our experiments, biodiesel produced from safflower will be preferred. A highly reactive fuel consisting of diesel fuel, biodiesel and diethylether to be used in the experiments planned to be carried out was used. As a low reactivity fuel, LPG was sent to the inlet manifold at a fixed 50% rate. Each test fuel was also conducted under 2 different engine operating conditions ( 1. Engine loaded: 7.2 kW medium load 2. RCCI mode 50%). Emission, combustion degree and performance measurements were made. As one of the most important positive results of this study, the RCCI strategy can increase BTE values. It is seen that BTE values increase with increasing compression ratio for all test fuels. Comparing the different RCCI modes for test fuels, it is seen that the BTE values are quite high and surpass diesel fuel in high DEE operating conditions. Therefore, the highest thermal efficiency values were obtained for B90/DEE10 and B85/DEE15 RCCI operating conditions for all CR values. It is clearly seen that the BSEC values increase for the Biodiesel/DEE RCCI modes. These positive situations are undoubtedly due to the RCCI operating modes. Especially in RCCI application, reasons such as increase in flame speed, near-complete combustion and decrease in heat transfer have increased efficiency. The elimination of high temperature zones near the cylinder wall and piston head surfaces is also an important factor in RCCI combustion. This reduces heat transfer losses and increases the expansion work. A second reason is that the implementation of RCCI makes it easy to control the start and end of combustion. Combustion timing and duration are optimized with combustion control. Compression work is reduced and expansion work is increased, which has increased the efficiency and overall performance of the engine.