Based In Europe is the CIMAC organisation, giving world-wide coverage, with, for example, its emissions, fuels & Lubricants working groups, its recommendations for fuels, its lubrications guidelines for Low Speed, Medium Speed & High Speed engines as we have heard from JF Chapuy and KC Lim. [ref.1 CIMAC papers 1998 & JF-C/KC Lim ISME 2000].
Also in Europe is the CEC. Amongst its numerous active groups is the investigation group IL-047 with responsibilities for the Lubrication of Large Diesel Engines. This group has concentrated upon used oil sampling and recommended analytical methods, investigations into high oil consumption in medium speed diesel engines, and more recently the paper on the impact of heavy fuel oil contamination on lubrication quality [ref.2 CEC Symposium 1997, CIMAC 1998, lofE award 1999]
North America is well supported via major organisations, for example by SAE, ASTM, STLE and ASME.
Lubricants
Challenges to developing advanced lubricants stem from OEM developments, user expectations, compliance with environmental targets, better understanding of the responses of the oil in the engine and the new lubricant components.
Principal equipment developments
During this Symposium we have heard much about advances in engine designs and operations.
・ power outputs
・ metallurgies
・ electronic management systems controlling fuel injection timing, valve operations etc.
・ camshaft-free designs
・ diesel-electric
・ alternative propulsion systems
Fuels
As this millenium proceeds there are certain to be changes to engine fuels, as this Symposium has or will hear.
・ qualities (see discussion forum and paper by G Fleischhack, for example).
・ impact of hyrodgen economy
・ alternative fuels/exotic fuels - an important topic to be studied by CIMAC LWG in the future
・ impact of gas turbine technologies in marine
Emissions controls
Principally, the legislative activities through IMO and national bodies have set the pace for changes that have resulted in controls of SOx and NOx. The next phase
may tackle particulate emission controls and the further reductions in hydrocarbons and CO2.
Engine efficiencies
The main goal of increasing efficiency of operation will ultimately lead to the adiabatic engine. As a step nearer, the development of combined cycle operations/hot combustion engines certainly makes for more efficient energy use and total availability. However, thermal stresses on engine components, both solid and liquid, are the greater.
Currently different metallurgies, the limited use of ceramics, of special coatings, generate associated challenges for lubricants and the ways in which lubricants need to function. This trend will continue.
Ancilliary equipment
The engine developments not only pose challenges for more advanced lubrication within the engine but also pose lubricant response targets within the filter and centrifuge systems as oil contamination levels change.
For compliance with emissions controls, exhaust catalyst systems are, and will be, increasingly employed. How the catalyst and the oil components in the exhaust gases interact will strongly impact on efficiency and, has happened in the area of gas engine oils, dictated a performance criterion linked to additive chemistry and certain elemental concentrations, in particular phosphorus.
Linked to the catalyst compatibility feature may be the protection of gearboxes when or if the crankcase lubricant is used also to lubricate the gearbox.
I wish to concentrate on the reciprocating engines and the main reasons for either achieving advances in lubrication or to point towards further advances that will be required during the coming years.
Principles
The basic principles of tribology will still remain. The relative importance of any given wear mechanism will change - scuffing, pitting, abrasion, corrosion, erosion as new developments occur. During this conference we have heard from Schenk, Aabo & Hengeveld about the effects of temperature and loads on wear mechanisms in cross head engines. Linked to that is the greater understanding of acid formation and dew point that changes as temperatures and firing pressures increase. This has been an important factor compensated by the practical increase in cylinder liner temperatures over the last decade from around to well above dew point temperatures. With that trend came the greater need to build in the anti-wear features of current cylinder oils, rather more than the acid neutralisation needed in earler times.
Water injection in various ways - direct injection, humidified inlet air or emulsions of water in fuel - led to a debate that no doubt will coninue, on the merits of each system between their respective developers.
