Combustion characteristics of compression ignition engine fuelled with rapeseed oil–diesel fuel–n-butanol blends

Liquid biofuels for compression ignition engines are often based on vegetable oils. In order to be used in compression ignition engine the vegetable oils have to be processed because of their high viscosity or it is also possible to use vegetable oils in fuel blends. In order to decrease the viscosity of the fuel blends containing crude vegetable oil the alcohol-based fuel admixtures can be used. The paper describes the effect of rapeseed oil–diesel fuel–n-butanol blends on combustion characteristics and solid particles production of turbocharged compression ignition engine. The 10% and 20% concentrations of n-butanol in the fuel blend were measured and analysed. The engine Zetor 1204, located in tractor Zetor Forterra 8641 with the power of 60kW and direct injection was used for the measurement. The engine was loaded through power take off shaft of the tractor using mobile dynamometer MAHA ZW500. The measurement was carried out in stabilized conditions at 20%, 60% and 100% engine load. The engine speed was kept at 1950 rpm. Tested fuel blends showed lower production of solid particles than diesel fuel and lower peak cylinder pressure and with increasing concentration of n-butanol in the fuel blend the ignition delay was prolonged and premixed phase of combustion was increased.