US 11,685,872 B2
Method for reducing piston deposits in a marine diesel engine
Jonathan M. Hughes, Abingdon (GB); Timothy M. Clitherow, Didcot (GB); and Adam P. Marsh, Witney (GB)
Filed by Infineum International Limited, Abingdon (GB)
Filed on Aug. 7, 2020, as Appl. No. 16/987,694.
Claims priority of application No. 19191918 (EP), filed on Aug. 15, 2019.
Prior Publication US 2021/0047576 A1, Feb. 18, 2021
Int. Cl. C10L 10/04 (2006.01); C10L 10/06 (2006.01); C10L 1/16 (2006.01); C10L 1/196 (2006.01); C10L 1/14 (2006.01)
CPC C10L 10/04 (2013.01) [C10L 1/143 (2013.01); C10L 1/1616 (2013.01); C10L 1/196 (2013.01); C10L 10/06 (2013.01); C10L 2270/026 (2013.01)] 14 Claims
 
1. A method of reducing the incidence of deposits on the pistons of a 4-stroke marine diesel engine during operation of the engine when it is fuelled with a marine residual fuel meeting the ISO 8217 2017 fuel standard for marine residual fuels and having a sulphur content of more than 0.1% and less than 0.5% by mass, based on the mass of the fuel, the method comprising lubricating the engine using a lubricating oil composition comprising:
(a) at least 50% by mass, based on the mass of the composition, of an oil of lubricating viscosity;
(b) 5 to 25% by mass, based on the mass of the composition, of an oil-soluble or oil-dispersible alkali metal or alkaline earth metal salicylate detergent, or a mixture of two or more oil-soluble or oil-dispersible alkali metal or alkaline earth metal salicylate detergents, the or each oil-soluble or oil-dispersible alkali metal or alkaline earth metal salicylate detergent having a total base number of (TBN) as measured by ASTM D2896 of from 50 to 500 mg KOH/g;
(c) 0.1 to 10% by mass, based on the mass of the composition of one or more oil-soluble or oil-dispersible ashless dispersants; and optionally,
(d) 0.1 to 10% by mass, based on the mass of the composition of a polyalkylene-substituted succinic anhydride,
wherein the lubricating oil composition provides the engine with reduced asphaltene agglomeration and/or reduced deposits on piston and ring assemblies, as compared with a lubricating oil composition lacking component (c) and/or component (d).