Non-surfactant water-in-diesel emulsion fuel (NWD) is an alternative fuel that has the potential to reduce major exhaust emissions while simultaneously improving the combustion performance of a diesel engine. NWD comprises of diesel fuel and water (about 5% in volume) without any additional surfactants. This emulsion fuel is produced through an in-line mixing system that is installed very close to the diesel engine. This study focuses mainly on the performance and emission of diesel engine fuelled with NWD made from different water sources. The engine used in this study is a direct injection diesel engine with loads varying from 1 to 4 kW. The result shows that NWD made from tap water helps the engine to reduce nitrogen oxide (NOx) by 32%. Rainwater reduced it by 29% and seawater by 19%. In addition, all NWDs show significant improvements in engine performance as compared to diesel fuel, especially in the specific fuel consumption that indicates an average reduction of 6%. It is observed that all NWDs show compelling positive effects on engine performance, which is caused by the optimum water droplet size inside NWD.
The focus of this work is to investigate the emission characteristics of a stationary diesel engine while utilizing an emulsion fuel from a novel preparation process. The emulsion preparation was performed in real time without using any surfactant. Instead of mechanically breaking the water down into droplets, the water is delivered thermally, by changing its phase from gas to liquid. Steam is used in this proposed process, where it will be converted into suspended water droplets once it meets colder diesel. The product is called steam-generated water-in-diesel emulsion fuel (S/D). The method is expected to reduce the moving components of a previous surfactant-less system; therefore, reducing costs and increasing the system reliability. The emission characteristics of S/D were compared with EURO 2 diesel (D2), and a conventional emulsion denoted as E10. E10 was prepared using 10% water (volumetric) and SPAN80 as a surfactant. The emission characterizations were carried out based on the exhaust gas of a single cylinder naturally aspirated CI engine fueled with D2, S/D, and E10. Compared to D2, both emulsions significantly reduced the emissions of nitrogen oxides (NOx) (E10 max ↓58.0%, S/D max ↓40.0%) and particulate matter (PM) (E10 max ↓20.0%, S/D max ↓57.0%).
We investigate the dynamics of high energy dual regime unidirectional Erbium-doped fiber laser in ring cavity, which is passively Q-switched and mode-locked through the use of an environmentally friendly graphene filament-chitin film-based saturable absorber. The graphene-chitin passive saturable absorber allows the option for different operating regimes of the laser by simple adjustment of the input pump power, yielding, simultaneously, highly stable and high energy Q-switched pulses at 82.08 nJ and 1.08 ps mode-locked pulses. The finding can have applications in a multitude of fields due to its versatility and the regime of operation that is on demand.
Malaysia is one of the top exporters of palm oil, and although currently facing fierce resistance towards palm oil imports in some parts of the globe, one of the ways to utilize this commodity is by increasing palm biodiesel content in local commercial diesel. However, due to the oxygen-rich nature of biodiesel, its utilization suffers from increased nitrogen oxides (NOx) emission compared to conventional diesel. To mitigate this issue and improve diesel engine performance and emissions using biodiesel-diesel blends, this study attempted to investigate implementation of a real-time non-surfactant emulsion fuel supply system (RTES) which produces water-in-diesel emulsion as fuel without surfactants. NOx reducing capability of water-in-diesel produced by RTES has been well documented. Therefore, in this study, 30% biodiesel-diesel (B30) was used as the base fuel while B30-derived emulsions consisting of 10 wt%, 15 wt% and 20 wt% water content were supplied into a 100 kVA, 5.9-L common rail turbocharged diesel engine electric generator. Fuel consumption and exhaust emissions were measured and compared with commercially available Malaysian low grade diesel fuel (D2M). Evidence suggested that emulsified B30 biodiesel-diesel produced by RTES was able to increase brake thermal efficiency (BTE) up to a maximum of 36% and reduce brake specific fuel consumption (BSFC) up to 8.70%. Furthermore, B30 biodiesel-diesel emulsions produced significantly less NOx, carbon monoxide and smoke at high engine load. In conclusion, B30 biodiesel-diesel emulsions can be readily utilized in current diesel engines without compromising on performance and emissions.