An Analysis of the Ambient Condition Effect on Biodiesel Spray Using Constant Volume Chamber

Abstract

Diesel engines are high compression ignition engine which are now very vastly used for heavy vehicles and machineries. Diesel fuel is compressed under the right condition to ignite inside the constant volume chamber. Researchers have been studying for many years on ways to increase the efficiency of diesel engine as well as reduce the emission. The main idea of this research is to understand the effect of temperature on the spray characteristics, as well as fuel-air mixing characteristics. These are the characteristics responsible for ignition of diesel sprays. This research is first conducted by investigating the influence of biodiesel properties and ambient condition on the mixture formation especially at early stage of fuel-air premixing. This research was continued with injecting diesel fuel into the chamber using a Bosch common rail system. Direct photography technique with a digital camera was used to capture the real images of spray evaporation, spray length, and mixture formation with the time changes. The values of the temperature were recorded at ambient temperature, 55°C, 70°C, 85°C as well as 100°C. Injection pressure of 0.1 MPa up to 0.7 MPa was induced into the chamber with an increment of 0.1 MPa. The condition to which the fuel is affected was estimated by combining information on the block temperature, ambient temperature and photographs of the spray. The increase in block temperature increases the ambient temperature inside the chamber resulting in gain of spray area and wider spray angle. Thus predominantly promotes for a better fuel-air mixing.