M Man Bw low 10 speed engines

MAN B&W Diesel's roots are closely entwined with the early days of the diesel engine through both its German and Danish branches, respectively MAN and Burmeister & Wain. Both groups evolved distinctive low speed two-stroke crosshead engine designs before MAN acquired control of B&W in 1980. MAN subsequently discontinued the development of its own loop-scavenged engines at Augsburg and centred all low speed design and R&D operations in Copenhagen, pursuing the refinement of the MAN B&W uniflow-scavenged programme in the shape of the MC series.

The prototype, an L35MC model, entered service in 1982 and the first large bore example, a six-cylinder L60MC engine, was started on the Christianshavn testbed in September 1983. The full L-MC programme was introduced in 1982 with bore sizes of 350 mm, 500 mm, 600 mm, 700 mm, 800 mm and 900 mm. Refinement of the MC design and the introduction of new bore sizes (260 mm, 420 mm, 460 mm and 980 mm) and stroke options continued through the 1980s/1990s in line with service experience and market trends. The current portfolio embraces 11 bore sizes from 260 mm to 1080 mm and K (short stroke), L (long stroke) and S (super-long stroke) variations, with stroke-bore ratios ranging from 2.44 to 4.2:1 and rated speeds from 56 rev/min to 250 rev/min.

Output demands from around 1100 kW to 97 300 kW are now covered by four- to 14-cylinder in-line models in the MC programme, whose individual rating envelopes are illustrated in Figure 10.1. Additions to the portfolio and key parameter refinements over the years—progressing to Mark 7 versions with mean effective pressures of 19 bar or higher—are shown in Table 10.1. Performance curves are typified by those for an S60MC engine (Figure 10.2).

Electronically-controlled ME versions of the 500 mm to 1080 mm bore models (detailed below) were progressively introduced from 2001 to offer the same outputs as their MC engine equivalents.

Choosing the most appropriate model for a given ship and propulsion duty is eased by MAN B&W's Computerized Engine Application System, which includes an integral speed and power prediction programme

Power BHP kW x 1000

Power BHP kW x 1000

50 60 70 80 100 120 140 160 200 250

Speed r/min

Figure 10.1 MAN B&W Diesel's MC engine programme. A K108MC model has taken the output threshold to 97 300 kW.

50 60 70 80 100 120 140 160 200 250

Speed r/min

Figure 10.1 MAN B&W Diesel's MC engine programme. A K108MC model has taken the output threshold to 97 300 kW.

for ships and the corresponding main engine selection programme. Optimized solutions (bore size, number of cylinders, speed/power ratings) can be determined on the basis of both technical and economical data input. The system—comprising a number of integrated sub-programmes which are hierarchically arranged—facilitates calculations of such parameters as fuel consumption, utilization of exhaust gas heat and maintenance costs, and allows economic comparisons of the various options.

The layout diagram in Figure 10.3 (in this case for an S60MC engine) shows the area within which there is full freedom to select the combination of engine power (kW) and speed (rev/min) that is the optimum for the projected ship and the expected operating profile. The engine speed (horizontal axis) and engine power (vertical axis)

Table 10.1 Milestones in the evolution of MAN B&W Diesel's MC programme

Year

Development

Mark

Mep (bar)

Mean piston speed (m/sec)

Pmax (bar)

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