Laboratory of Heterogeneous Mixtures and Combustion Systems
Abstract
Fuel characteristic and exhaust particulate emissions tests were carried out for a EURO5 compliant Heavy Duty Vehicle operating on both pure petroleum diesel (PD) and used cooking oil (C2G Ultra Biofuel) PD blends under real world driving conditions. Fuel tests showed that fuel temperature, substitution ratio and engine speed play a key role in determining the spray characteristics of the Ultra Biofuel blends. However, under real world operating conditions, the Bioltec fuel blending system was found to overcome these effects by using lower C2G Ultra Biofuel:PD substitution ratios during cold start and low speed conditions. Overall the fuel tests suggested it to be convenient to operate the engine on blends with Ultra Biofuel content up to 80% to avoid higher fuel consumption and higher pollution load on the exhaust after treatment system, particularly at low temperatures and rpm. In the real world tests, average substitution ratios of 85% were achieved, with close to 100% Ultra Biofuel achieved for high speed steady state conditions, with no negative impact on particulate emissions. The vast majority (60-80%) of the particulate mass within the exhaust was found within size fractions below 2.5 μm for both fuels and was thus within the respirablem range. The PD produced around twice the concentration of particulates within these finer fractions compared to the equivalent trips using the blended fuel. Thermo-gravimetric Analysis demonstrated that the PD produced higher concentrations of black carbon (soot) and the Ultra Biofuel blends more organic carbon within the particulates. The tests demonstrate that when using an effective fuel substitution strategy, Ultra Biofuel has the potential to reduce both lifecycle CO2 and respirable particulate emissions leading to potential climate and air quality benefits
