Abstract
Biodiesels are a renewable energy source, and they have the potential to be used as alternatives to diesel fuel. The aim of this study is to investigate the wear and friction characteristics of Australian native first generation and second generation biodiesels using a four-ball tribo tester. The biodiesel was produced through a two-step transesterification process and characterized according to the American Society for Testing and Materials (ASTM) standards. The tribological experiment was carried out at a constant 1800 rpm and different loads and temperatures. In addition, the surface morphology of the ball was tested by scanning electron microscope (SEM)/energy dispersive X-ray spectroscopy (EDX) analysis. The test results indicated that biodiesel fuels have a lower coefficient of frictions (COF) and lower wear scar diameter (WSD) up to 83.50% and 41.28%, respectively, compared to conventional diesel fuel. The worn surface area results showed that biodiesel fuel has a minimum percentage of C and O, except Fe, compared to diesel. In addition, the worn surface area for diesel was found (2.20%–27.92%) to be higher than biodiesel. The findings of this study indicated that both first and second generation biodiesel fuels have better tribological performance than diesel fuel, and between the biodiesel fuels, macadamia biodiesel showed better lubrication performance.
Highlights
Biodiesel is a most promising alternatives to fossil fuel as it can play a significant role in fulfilling the energy demand and lowering the greenhouse gas emissions into the environment [1,2]
Crude macadamia oil was collected from the local market in Rockhampton, and crude beauty-leaf oil was received from a colleague through personal communication
wear scar diameter (WSD) analysis results showed that both biodiesels lower the WSD by 19.65% to 41.28% compared to the diesel fuel, depending on the load
Summary
Biodiesel is a most promising alternatives to fossil fuel as it can play a significant role in fulfilling the energy demand and lowering the greenhouse gas emissions into the environment [1,2]. Biodiesel is gaining popularity these days due to having some superior qualities to fossil diesel fuels such as renewability [7], biodegradability [8], higher flash point [9], cetane number [10], lubricity and less greenhouse gas emissions like CO, HC, PM, etc. The major drawbacks of biodiesel are that it causes injector coking, carbon deposition, oxidation and corrosion due to the presence of higher unsaturated fatty acids in its structure [14,15]. These problems may lead to the friction and wear in different moving components such as cylinder liners, bearings, cams, tappets, crankshaft journals, pistons and piston pins, valve guides, valve systems, etc. These problems may lead to the friction and wear in different moving components such as cylinder liners, bearings, cams, tappets, crankshaft journals, pistons and piston pins, valve guides, valve systems, etc. [16]
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