Medium-speed slows

Developments on the medium-speed side have concentrated on further emission reductions.

The need to modify products to meet the IMO?s NOx limit and the pre-certification process has kept the medium-speed engine manufacturers busy over the last year or so. Emission reduction remains the centrepiece of many R&D efforts, so new products have been few and far between and look likely to stay that way. By far the biggest launch has been the MAN B&W 27/38 in both genset and propulsion versions (The Motor Ship, October 1999) but others have plans too.

Belgian engine manufacturer ABC plans to boost exports to Germany and eastern Europe with more powerful V12 and V16 additions to its existing DZC engine range. With a bore of 256mm and a stroke of 310mm, the current in-line six and eight cylinder versions have outputs from 864kW (1,175 bhp) at 720 rev/min to 1,768kW (2,404 bhp) at 1,000 rev/min ? the vee engines will see this almost doubled.

The new engines will retain the distinctive push rod tubes on the outside of the vee, and will also keep the segmented camshafts. Twin turbo-chargers (one per bank) will push air through the four valve heads to give a bmep of 18.1 bar and a pmax of 114 bar. Mechanical fuel injection will be retained and TBO are expected to start at around 15,000 hrs.

Wartsila NSD has seen its first 64 engine at sea, and it is also the first seven cylinder medium-speed engine produced by the company. The introduction of the W64 opens up fresh areas for medium-speed propulsion and the company feels the four strokes will gain market share and move outside specialist tonnage.