The reduction of friction and pumping losses in engines is important. Otherwise, the engine has to work that extra bit harder – up to 20 per cent of the total power produced can be wasted.
Researchers from Purdue University, Indiana, US have addressed the problem by adding tiny, and perfectly smooth, carbon spheres to motor oil. This can reduce friction and engine wear by up to 25 per cent.
This offers major benefits in reducing friction and thus improved fuel economy.
Motor oil containing three per cent of the tiny spheres by weight, each measuring between 100-500 nanometres in diameter, delivered a reduction in friction between 10 and 25 per cent.
The multidisciplinary team, made up of chemical and mechanical engineers, have also investigated how to potentially mass-produce the tiny spheres additive with the use of ultrasound to speed up chemical reactions in the manufacturing process.
Vilas Pol, an associate professor of chemical engineering at Purdue, said: “People have been making these spheres for about the last 10 years, but what we discovered was that instead of taking the 24 hours of synthesis normally needed, we can make them in five minutes.”
Ultrasound is used to produce bubbles in a fluid containing resorcinol and formaldehyde. The bubbles expand and collapse. This generates heat to drive chemical reactions that produce polymer particles, which are then heated to 900°C to form smooth spheres of pure carbon.
Vilas worked with doctoral researchers from Purdue’s chemical and mechanical engineering departments: Abdullah A. Alazemi; Vinodkumar Etacheri; and Arthur D. Dysart. As well as Farshid Sadeghi, Cummins Distinguished Professor of Mechanical Engineering and Lars-Erik Stacke, an engineer from SKF Engineering & Research Centre in Gothenburg, Sweden.
Together, they published their research – Ultrasmooth Submicrometer Carbon Spheres as Lubricant Additives for Friction and Wear Reduction – in the ACS Applied Materials and Interfaces journal.
The diameter of the tiny spheres matches the ‘surface roughness’ of moving engine components, and due to their shape and smoothness, they can help fill these gaps and reduce friction.
Abdullah said: “Introducing microspheres helps separate the surfaces because the spheres are free to move. It also is possible that these spheres are rolling and acting as little ball bearings, but further research is needed to confirm this. It’s very important not to increase the viscosity because you want to maintain the fluidity of the oil so that it can penetrate within engine parts.”
Further research will be conducted into the behaviour of these tiny spheres, as well as refining the manufacturing process of the resorcinol-formaldehyde particles into the finished product.
I wish the team the very best of luck with their spherical endeavour. If all goes well, we will see more fuel efficient engines as a result.
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