Performance and Emission of Non-surfactant Water-in-Diesel Emulsion Fuel Using Light-Duty Trucks on Urban Road Conditions

In road transport, varying fuel flow rates make it hard to maintain a consistent water ratio in non-surfactant emulsion fuels using the Real-Time Non-Surfactant Emulsion Fuel Supply System (RTES). Thus, it becomes more reasonable to establish an appropriate range of water content tailored to a road condition. Therefore, this study aims to evaluate fuel consumption and exhaust emissions of non-surfactant emulsion fuel in light-duty trucks equipped with RTES, focusing specifically on urban conditions. On-road testing and 300-s idling tests were used as the urban conditions to compare diesel with non-surfactant Water-in-Diesel Emulsion (WiDE) fuel with water percentages from low to high concentrations of water, namely WiDE low%, WiDE med%, and WiDE high%. During idling tests, all emulsion variants reduce fuel consumption. WiDE high% exhibits the most substantial NOx reduction of 9.2%. On-road testing reveals comparable WiDE and diesel fuel consumption, despite the RTES increased electrical load. WiDE high% shows an increment for NOx and CO emissions by 11.71% and 202.19%. In conclusion, a 7.4% to 21.1% water content range was suggested for non-surfactant emulsion fuel in urban road conditions.