Combustion characteristics of direct injection diesel engine fueled with biodiesel

A turbocharged, direct injection diesel engine fueled with biodiesel and diesel was used to conduct performance tests. In order to investigate the effect of biodiesel on combustion characteristics, the injector needle lifts, injection pressure and gas pressure in cylinder were recorded and some parameters of combustion were analyzed, such as heat release rate, ignition delay. The results indicate that with increase of biodiesel addition, start of injection is advanced and injection delay increases; injection pressure and injection duration increases little; ignition delay is shortened gradually, especially on heavy load; the peak value of premixed burning rate decreases while the maximum diffusive burning rate increases; maximum cylinder gas pressure is improved and its corresponding crank angle is advanced. In addition, with biodiesel the effective thermal efficiency of engine increases, which is greatest on middle load.