In today's environmentally aware society the large-bore diesel engine is not alone in coming under scrutiny. Although only 0.25 to 0.35% among the total exhaust gases produced by this type of engine are toxious compounds, even such small amounts still need to be reduced further. MAN B&W Diesel, market leaders in the production of large-bore two-and four-stroke diesel engines covering the output bracket between 680 hp and almost 100 000 hp per engine (Fig. 1), have been facing up to this challenge for almost a decade. Taking state-of-the-art MAN B&W four-stroke engines as its example, this paper outlines the causes and effects of the major pollutants, including carbon dioxide, the "greenhouse gas," and describes some of the options available for reducing them [1]. The NOx emission control measures implemented in the current generation of MAN B&W diesel engines ensure that they comply with statutory emission limits. Since the time this paper was compiled (January 2000) much progress has been achieved in reducing pollutant emissions from diesel engines, in particular as regards smoke emissions from cruise vessels slow-steaming in strictly protected tourist areas. As an example the authors' company introduced an IS version (IS = invisible smoke) for their largest medium-speed diesel engines in September 2000, featuring invisible exhaust plumes in transient operation between idling and full load. Fig. 1MAN B&W slow-speed and medium-speed diesel engine program (status: 1999)
Matching simulated and measured eigen frequencies of medium speed diesel engine
