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of the lubricant market. It does significantly contribute to improve the image of the lube industry with view to ecological aspects and sustainability.
Regenerated waste oils can save up to 700 million barrels of crude oil annually, making the EU industry and society less vulnerable to high prices, market volatility and the political situation in supplying countries.
Using modern regeneration technologies, CO2 emissions (kg of CO2
per ton of base oil) can be
reduced by more than 50% as compared to the virgin production of base oil.
Same but different Virgin refining and regeneration (re-refining) serve the same market and use the same molecules. While virgin refineries meet the large scale demand, regeneration cares for smaller-scale applications and realises the producer responsibility of the lubricant manufacturers by converting waste oil into again valuable products including environmental and social benefits. The industry as a whole can be proud of such a relationship!
LINK
www.geir-rerefining.org
The trick, therefore, is to use an oil with a low detergent content, which instead of carrying the dirt and soot in suspension, allows it to flush through into areas of low velocity, such as sumps, filter bowls and oil tanks. In fact the 27 litre V12 Rolls-Royce Merlin features a hollow crankshaft with so-called ‘sludge traps,’ which can be cleaned out at rebuild. Merlin engines are rebuilt every 500 hours!
Later versions employed in airliners such as the Canadair Argonaut and Avro Tudor had standpipes to ensure a clear flow of oil through the sludge layer which builds up by centrifugal action in the hollow journals. The Bristol Hercules engine, with its contamination-sensitive sleeve-valves, even had a high speed centrifuge in the oil return system to help remove the unwanted combustion products.
The relatively high oil consumption of these engines contributes to the amount of soot the oil has to contend with. A Merlin can consume up to 11 litres of oil per hour and still be within spec. Cylinder oil-control is one of the ways in which internal combustion engines have been completely transformed over the years.
Lubricating oil for World War II aero-engines was originally specified in 80, 100 or 120 grade to specification D Eng RD 2472A or B, roughly equivalent to straight SAE 40, 50 or 60. It still is - nothing changes quickly in aviation! For any engine not being used for flight, we use Morris Lubricants` Golden Film SAE50 Classic Motor Oil.
LUBE MAGAZINE NO.143 FEBRUARY 2018 13
It is fair to say that most older engines in use today tend to run for relatively short periods and in the warmer months. One notable exception is the number of large piston-engine aircraft still operating on freight duties in Canada and the Soviet Union. One of the inherent disadvantages of monograde oils, their high viscosity at low temperatures, is less of an issue nowadays, however back in the day, aircraft were equipped with a so-called ’oil dilution system,’ where petrol was introduced to the engine oil returning to the dry-sump tank before shutting down. This had the effect of reducing the viscosity at start up, the petrol then boiling off as the oil warmed up. This is probably one of the last things you would subject a modern engine to, but that illustrates just how engines and lubricants have progressed in 70 years.
LINK
www.flightengineering.co.uk
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