The Modern Two-stroke Diesel Engine
At the turn of the millennium MAN B&W Diesel's two-stroke engine programme more than ever reflects the results derived from working closely with customers and engine builders worldwide. This process has helped shape the design and the manufacturing processes, eventually leading to the successful launch of three new large bore engines, the K98MC, the K98MC-C and, most recently, the S90MC-C.
This paper presents selected design features in detail, along with the test results and the service experience gained from these engines.
Additional attention is paid to the service experience acquired with the small bore and medium bore S-MC-C engines, which have profoundly influenced the most recent component and structural designs.
Key Words: K98MC/MC-C, Design, Testbed, Service
The dominant prime movers in the marine two-stroke market, low speed diesel engines, are also the prime digesters of "bottom of the barrel" heavy fuel oils, while they still demonstrate high reliability and high thermal efficiency at all loads. The challenges for the coming years will be to ensure that they continue doing so while still complying with ever-stricter environmental legislation . Low speed engine technology will be enhanced under its traditional umbrella of reliability and efficiency, so as also to use off-spec fuels beyond typical marine type heavy fuels as well as liquefied and compressed combustible gases like LPG, VOC and LNG. Electronics will play an increasing role in the technology used for low speed engines in the years to come. The high pressure gas injection version of the low speed engines is now on the market, taking advantage of the latest state-of-the-art electronic controls. Engines with electronic/hydraulic control of exhaust and fuel valve timing are already commercially available, offering higher flexibility under changing operating conditions.
2. THE MC ENGINE PROGRAMME
The MC engine programme in 2000 comprises 25 two-stroke engine types, as seen in Fig.1, plus special versions for power plant applications, high-pressure gas injection and electronic control (intelligent engine). The continuous development of the MC engine is supported by a wealth of experience gained from nearly 5,000 MC engines in service, as can be seen from the reference list, Fig.2.