Abstract
This paper describes the design and feasibility tests of a 570 mm bore 4 stroke low pressure
(L.P.) dual fuel engine rated at 20.9 bar BMEP meant for the propulsion of LNG carriers. The basic design features which are to be in accordance with classification societies safety rules are described : individual electro hydraulic valves located in the air manifold ducts, pilot injection, monitoring system etc....The engine capability to burn variable liquid /gas fuel proportions have been investigated with diesel oil and heavy fuel and possible running zones are defined. This ensures the possibility of the engine to cope with the different boil off gas quantity emanating from the ships tank during her loaded - and ballast -journeys. With the very lean setting of this engine, no adverse influence of the high ash lube-oil additives were found during the tests. Further tests are necessary to confirm that possible more significant fouling of the combustion chamber is still acceptable.