Fuel Spray, Engine Deposit and Real Driving Emissions Analysis of Heavy Duty Trucks Using Used Cooking Oil as a Fuel

The current project represents the first attempt to test the environmental performance of the direct utilisation of purified used cooking oil as a fuel in a heavy goods vehicle under real world driving conditions. The properties of the used cooking oil were different from those of petroleum diesel (PD) standards however, its heat value, carbon footprint reduction potential and low cost were the key incentives driving it’s use as a fuel.
The current research was a collaborative project between Convert to Green (C2G), the fuel provider, the United Biscuits Midlands Distribution Centre, the heavy goods vehicle provider and the University of Leeds as the scientific consultant and research executor.
The brand of used cooking oil was Convert to Green Ultra-biofuel (C2G UBF) tested on a Mercedes-Benz EURO 5 emissions standard compliant 44 tonne articulate heavy goods vehicle (HGV). The HGV was modified for on-board UBF heating and mixing with PD. UBF was heated by heat recovery from the engine cooling system.
The results showed that the UBF/PD blending ratio was 0.845 as a journey average for the entire test series. However, the HGV was recorded to run on 100% UBF at steady high speed on the M1 motorway in the Midlands region of the UK. There were no discernible deficiencies in the HGV’s performance or its traction effort. Nevertheless a slight increase in specific fuel consumption (SFC) was detected for the blended fuel. Engine durability, combustion chamber deposits and maintenance frequency were not affected by the UBF content in the fuel.
Although the engine technology was designed to suppress particulate matter (PM) within the combustion process, the use of blended UBF further reduced the tailpipe PM emissions compared to the use of PD. Carbon monoxide emissions decreased when using the blended fuel, while nitrogen oxides, total hydrocarbons and carbon dioxide increased compared to PD emissions.
The benefits of UBF utilisation as a fuel lie in the huge carbon savings and reduced PM emissions when compared to the use of PD as well as its use in providing a cost effective fuel supply and waste management technique.