Abstract
Biodiesel fuel (BDF) is a renewable resource, and is a promising carbon neutral fuel. However, BDF has the properties of high viscosity and poor volatility. Therefore, the atomization of its spray seems to be inhibited, which results in problems such as severe engine deposits and injector coking. In this study, BDF is mixed with a low boiling fuel to improve its fuel properties. Ethanol was chosen as the fuel to be mixed with BDF because of its higher oxygen content, lower ignitability and higher volatility. The ethanol addition would exert a large influence on mixture formation, ignition, combustion, and exhaust emissions. In the experiments, the spray characteristics were measured by shadowgraph photography and Mie-scattered light photography, while the mixture concentration and ignitability were measured by chemiluminescence photography. The experimental results show that the liquid phase penetration decreased with increasing of the mixture ratio of ethanol to BDF, and the ignition timing and ignition position can be controlled by changing the mixture ratio of BDF and ethanol.
