Extensive range of new products launched MEDIUM-SPEED ENGINES
U
S-based GE Transportation has recently introduced a 12- and 16-cylinder range
of V250 diesel engines. These new models are claimed to deliver fuel savings of as much as 6.5% compared to previous engines, offering 25% greater power density, and meeting United States Environmental Protection Agency Tier II emission standards. The 12-cylinder version has a 250mm bore,
producing 3180kW at 1050rev/min, 3035kW at 1000rev/min, and 2732kW at 900rev/min. The 16V250 has a rating of 4237kW at 1050rev/ min, 4038kW at 1000rev/min, and 3632kW at 900rev/min. The cylinder head, water jacket, cylinder
liner, piston, and conrod can be extracted from the engine as one assembly by removing a minimum number of fasteners. Additionally, both inlet and exhaust manifolds are compactly arranged between cylinder banks to allow the fairly large bore engine to be packaged in a narrow overall width. Included in the design is a fuel injection
system, comprising an electrically controlled unit pump and a standard configuration side entry injector. The system provides flexible operation in a variety of applications, as well as optimised combustion for different speeds and loads. A PowerStar controller drives the fuel
injection system with advanced closing point detection in order to improve fuel economy and emissions control. Diagnostics and display of all engine parameters and faults are available without the need for a laptop computer, and engine protection algorithms also predict problems at an early stage to avoid engine damage. GE has also designed a turbocharger for
the V250, based on its proven designs, but with upgraded aerodynamic features to meet combustion design and engine efficiency requirements. It has an axial turbine and centrifugal compressor, with a design that is thought to yield higher boost pressure while staying within the stress and speed limits of the shaft and bearing design. The power assembly configuration was
governed by peak firing pressure, reliability, and life cycle requirements. The new three-ring articulated piston meets weight requirements and exceeds peak firing pressure requirements. Supported by the piston pin, the skirt and the pin boss are optimised to provide excellent lubrication and superior guidance. The cylinder head is claimed to be safer,
with a wall that is supported by a head gasket, thicker flame deck, larger exhaust seat ring cooling bores, and smooth transition areas to avoid stress concentrations. To ensure reliability, the connecting rod
now includes an increased bearing width and a smaller oil groove in the bearing shell. The angle between the shank and big end split line is said to maximise stiffness, at the same time allowing for disassembly through the crankcase bore. GE’s simulation tools were used to verify that the rod had a low risk of fretting.
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The 12-cylinder V250 GE medium-speed diesel engine.
The crankcase features a main bearing
capability that is increased to provide claimed high levels of reliability and durability. Block, crankshaft, and drive end are repackaged to offer sufficient room for bearing size increases. In order to optimise the V250 for marine
and stationary use, the following parts were developed:
• rigid and isolation mounting systems
• dual impeller cooling water pump • mechanical fuel transfer pumps • deep lube oil sump • class-certifiable integrated wire harness • explosion relief crankcase doors • heat shielding on exhaust system • •
flywheel and air start system seamless steel, shielded fuel lines.
Medium-speed orders A number of new orders have also been received by GE Transportation for its medium- speed engine range. One of the contracts is for two 7FDM 16-cylinder diesel engines for use aboard the new dredging pump barge, Weeks 3302, for Weeks Marine Inc, USA. Weeks 3302 booster barge was constructed
at C&C Marine and Repair Inc, Louisiana, and is about 50m long by 16m wide, with a draught of around 3m. The barge will be employed in beach nourishment, channel and berth deepening, and maintenance, as well as sediment removal from lakes and reservoirs. The pair of engines, with a rating of 4100hp
at 1050rev/min each, will run two centrifugal pumps. Manufactured at GE’s Grove City facility, Pennsylvania, installation of the engines was completed at Bender Shipbuilding, Alabama. The delivery was completed in February this year. The GE 7FDM engine series is available in
8-, 12-, and 16-cylinder configurations, for power ranges from 1004kW to 3355kW.
Engines for articulated tug-barge Further orders for GE’s 7FDM diesel engine were placed by Van Isle Barge Services, and Sea-Link Marine Services, both of Canada. The engines were installed aboard an articulated tug-barge combination (ATB), and were again built at GE’s Grove City facility. Sea Link’s contract was for a 12-cylinder
version, rated at 2500hp/1050rev/min, and had a rapid delivery time of just 90 days, compared with a usual 12 to 18 month deadline. The engine was applied as part of a repowering project for Hyannis, a decommissioned United States Navy YTB tug, which was due to undergo sea trials at the end of last year. Van Isle ordered an 8-cylinder model,
with a rating of 1750hp at 900rev/min. It was employed on Fairbanks (to be renamed Van Isle Link), which was commissioned in March. The ATB Van Isle Link and Hyannis
combination will augment Van Isle’s existing f leet and provide cargo services between Vancouver and Vancouver Island.
SHIP & BOAT INTERNATIONAL MAY/JUNE 2007
Platform supply vessel order A second GE 7FDM contract is for four medium-speed diesel engines to be supplied to IML Motori SpA, of Italy. They are to be installed upon two UT755 platform supply vessels being built by Rossetti Marino, Italy. The engines are equipped with an electronic
fuel injection system, which will offer a continuous rating of 2790kW each at 955rev/ min. Aiming to be environmentally-friendly, the engines carry MARPOL certification, along with compliance to engine international air pollution prevention. These engines were also built at the Grove
City centre, and were due for delivery in January and April 2007. One vessel is slated to begin operation in mid-2007, with the other in late 2007/early 2008.
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