【作者】

Markus Weber

【摘要】

该论文已在芬兰赫尔辛基举行的第28届CIMAC大会上发表。论文的版权归CIMAC所有。Recent years have shown significant changes in the way, how marine two-stroke Diesel engines are operated. Slowsteaming has reduced average load of such engines and load profiles have become more disperse. The more frequent operation at low engine loads lead to a phenomenon called cold corrosion, which means the corrosion of cylinder liner running surface due to attack of sulphuric acid from burning sulphur-containing fuels, yielding pronounced wear and tear of cylinder liner and piston rings. This paper aims at displaying the measures taken by Winterthur Gas & Diesel Ltd. to investigate the physics behind the described phenomena and to implement design features to reduce the leverage of negative effects of slow-steaming in favor of ship operators and ship owners. The measures taken comprise the following: • Lubricant oil deposit control and optimised material combinations and surface machining to achieve minimal running-in wear and consecutive wear • Engine design adaptations to minimize condensation of sulphuric acid on the liner running surface and optimize distribution of cylinder lubricant strokewise and circumferentially • Investigations to understand the influence of recent engine layout (lower power and speed) and operation regimes (slow-steaming, turbocharger cut-off) and definition of measures to compensate adverse effects of these The success of above mentioned measures can be summarized as follows: • The current material combination with plateau-honed cylinder liner and Chrome-Ceramic piston ring running surface coating attains maximum corrosion protection and lowest possible wear over component life time. If, by any means, significant corrosive attack takes place, wear rate of cylinder liner and piston rings will increase during this period and goes back to regular level after suitable lubrication conditions have been re-established, because the piston ring coating does not disintegrate even under severe corrosive conditions. Corrosion scares will wear off in operation and normal wear regime will return • Gas-tight top piston ring lock design keeps lube oil and combustion deposits out of the ring pack and reduce the lubricant loss to both combustion chamber and piston underside space. Free moving piston rings are the prerequisite for trouble-free piston running over entire engine lifetime • Liner cooling bore insulation and - for latest engine designs - liner cooling water feed system with high temperature help to keep liner running surface temperature above dew point of water over the entire load range, which reduces the intensity of sulphuric acid condensation • Cylinder lubricant injection nozzles optimized by simulation algorithms in combination with distribution and retaining grooves on the cylinder liner surface ensure a perfect circumferential distribution of the cylinder lubricant • Optimised piston ring running surface profiling on the three-piston ring pack on latest engine designs keeps cylinder lubricant longer in the ring pack before releasing it for disposal • By choosing suitable (fuel-dependent) cylinder lubricant and controlling cylinder lube oil feed rate by appropriate piston underside drain oil sample analysis for remaining base number according to specified limit, cold corrosion of cylinder liners and consequential damage on piston rings can be avoided • Extensive operator information released for improving and optimizing operation on slow-steaming regime and with turbocharger cut-off translates innovation in technology to a monetary benefit for ship owners and operators Further design features planned for release during the next years will enhance the position of engine designs engineered by Winterthur Gas & Diesel Ltd., such as reduction of piston rings from three to two or one, inclined inlet ports, improved piston centering by a revolutionary piston skirt and closed-loop piston underside lube oil base number control. Investments into skilled pers

【会议名称】

第28届CIMAC会议

【会议地点】

芬兰 赫尔辛基

【下载次数】

2

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