The effect of different in-line mixers producing emulsifier-free bio-diesel emulsion on the diesel engine combustion performance and exhaust emission

Abstract

The energy crisis that the world facing right now causes researchers all over the world to opt for alternative fuels. Alternative fuels such as water in diesel emulsion gained attention in various studies due to their performance and capability in reducing harmful emissions such as NOx and PM. A new concept was introduced to make water in diesel emulsion without using a surfactant through a device called Real-Time Non-Surfactant Emulsion Fuel Supply System (RTES) and directly supply the fuel to the engine. This real-time emulsification concept requires a strong mixer, however, it consumes high energy. Thus, this study focused on the effect of different in-line mixers producing emulsifier-free bio-diesel emulsions on stability, diesel engine combustion, performance, and exhaust emission. The original RTES consists of a high shear mixer and ultrasonic mixer, while a new parameter for RTES (RTES-SM) is the high shear mixer and static mixer. The effect of the different inline mixers of RTES and RTES-SM was tested on the stability testing, engine dynamometer under various loading of 2 kW, 4 kW, and 6 kW, and real vehicle testing. The water percentage was set in the range of 7–10 %. Overall, the RTES showed better results on stability and engine dynamometer, but on real vehicle testing, the result is comparable to RTES-SM. Thus, this new concept of an inline mixing system of non-surfactant biodiesel emulsion (RTES-SM) showed better energy efficiency, promising results in real vehicle testing, and potential options in emulsion mixing technologies.