auxiliary engine · auxiliary system

MAN L27/38

The MAN L27/38 is a medium-speed, four-stroke marine diesel engine widely used aboard ships as an auxiliary engine driving a generator and, in some installations, for propulsion. In MAN's naming convention the L indicates an in-line cylinder arrangement and the numbers give the principal dimensions of the cylinder (a bore of 27 centimetres and a stroke of 38 centimetres) which places it among the robust, medium-bore engines that form the backbone of shipboard power generation. As a medium-speed engine it runs considerably faster than the low-speed two-stroke engines used for the main propulsion of large ships, but much slower than high-speed engines, a balance that gives it durability, the ability to burn heavier fuels, and long intervals between overhauls, while remaining reasonably compact. These qualities make it well suited to the demanding role of an auxiliary generating set, where the engine may run for long hours supplying the ship's electrical load and must start reliably and share load with other sets connected to the same switchboard. In the common auxiliary role, several such engines are each coupled to an alternator to form generating sets, and the ship's power management system starts, stops and shares load among them according to demand, providing redundancy so that the failure of one set does not black out the ship. In propulsion applications the engine drives through a gearbox, sometimes in a multi-engine or diesel-electric arrangement. Like all four-stroke marine diesels it requires planned maintenance of its fuel injection equipment, valves, turbocharger, cooling and lubrication systems, and it is designed to meet the applicable emissions standards for nitrogen oxides. The L27/38 typifies the dependable medium-speed engine on which ships rely for their electrical power and, in many vessels, for part of their propulsion, quietly underpinning the operation of everything from cargo gear to navigation equipment and accommodation services.