The determination of optimum injection pressure in an engine fuelled with soybean biodiesel/diesel blend

Abstract

In this study, the optimum blend rate and injection pressure in a four-stroke, single cylinder, direct injection diesel engine using soybean methyl ester were investigated experimentally. The tests were conducted at two stages. Firstly, the engine was tested with diesel fuel, B25 (25% biodiesel + 75% diesel fuel), B50, B75, and B100 fuels at full load and at a constant speed. According to the test results, it was determined that the most suitable fuel was B25 in terms of performance and emission. Secondly, the engine was tested at different loads with diesel fuel at original injection pressure and with B25 at different injection pressures (160, 180, 200, 220, and 240 bar) for comparison. It was determined from tests performed with B25 that the most suitable injection pressure in terms of performance and emissions was 220 bar. The specific fuel consumption and power values of the B25 were found to be nearly the same as those of diesel fuel at 220 bar injection pressure. In addition, HC, CO, and smoke emissions were reduced by about 33%, 9%, and 20%, respectively. On the other hand, NO x emission increased by about 12%.

Correlation and prediction of biodiesel density for extended ranges of temperature and pressure

“…However N6 had a composition far from that usually found in biodiesels. For PCS and SCHB biodiesels, the density deviations in predictions were low in the recommended (p, T) values for operation of injection systems (T % 344 K, p = 12-22 MPa) [3][4][5]. For PCS biodiesel, the predicted densities at the recommended injection (p, T) conditions were practically the measured ones.…”

“…delivered into the engine cylinder and mixed with air to achieve proper combustion mixture. This operation is carried out under pressure, usually at p % (15-50) MPa and moderate temperature T % (300-350) K, and is strongly affected by the fuel density [3][4][5]. With the common rail injection technology the pressure can reach up 100-120 MPa [6,7].…”

Experimental Investigation and Modeling of Thermophysical Properties of Pure Methyl and Ethyl Esters at High Pressures

“…The knowledge of thermophysical properties of pure components over large ranges of temperature and pressure is important for predicting the behavior of fuel injection and combustion systems in diesel engines where a precise amount of fuel must be delivered into the engine cylinder and mixed with air to achieve proper combustion . This operation is carried out under rapid variation of pressure and temperature and is strongly affected by the fuel density and viscosity. − Therefore, in order to achieve the correct fuel atomization and a complete combustion, proper values of density and viscosity are required, as well as of the speed of sound, which is related to the starting of a diesel engine. A higher speed of sound and isentropic bulk modulus of biodiesel results in a quicker fuel pressure rise from the fuel pump toward the injectors, which leads to earlier injection timing and, consequently, to a higher NO x emission. − …”

Influence of Diesel Fuel and Soybean Oil Ethyl Ester Blends on the Performance and Emission Characteristics of a Diesel Engine

“…CO, formed by the incomplete combustion of fuels, is produced most readily from petroleum based fuels, which contain no oxygen in their molecular structure [19,20,21,22]. As seen in Fig.…”