Press Information

MHI and Wärtsilä to Jointly Develop Small-size Marine Diesel Engines
With 350 mm and 400 mm Cylinder Bores

No.1252
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Tokyo, September 8, 2008 - Mitsubishi Heavy Industries, Ltd. (MHI) and Wärtsilä Corporation of Finland will jointly develop new small, low-speed marine diesel engines with cylinder bores of 350 and 400 millimeters (mm). The two companies agreed on joint design and development of engines of less than 450 mm cylinder bore in May 2008, based on a previously signed strategic alliance agreement.

The new engines, to have a power range of 3,500–9,000 kW, will be developed in collaboration, taking advantage of the strengths of the two companies. For both the 350 mm and 400 mm cylinder bore models, MHI will develop the mechanically controlled UEC-LSE series, and Wärtsilä will develop the Wärtsilä RT-flex electronically controlled common-rail engines and Wärtsilä RTA mechanically controlled engines. The first of the 350 mm bore engines will be available in the first quarter of 2011 and the 400 mm bore engines a year later.

The new engines will extend the low-speed engine range available for many types of small and medium-sized commercial vessels. They are being designed to provide the optimal power and speed for a wide variety of ship types, such as small handysize bulk carriers of less than 30,000 deadweight tonnage (DWT), product tankers, general cargo vessels, reefers, feeder container ships, and small LPG carriers. The market for the new engines in such vessels is world-wide, though there is a greater volume of such new constructions at shipyards in East Asia, especially China, Korea, Japan and Vietnam.

The key benefits of the new engines will be compliance with IMO Tier II emissions regulations, low fuel consumption, a low cylinder oil feed rate, high reliability, and long times between overhauls. They will also be able to provide optimum fits to ships in terms of power, propeller speed, dimensions, weight, and electrical power consumption, as well as being competitive in manufacturing costs.

The Mitsubishi UEC35LSE, Wärtsilä RT-flex35 and Wärtsilä RTA35 engine types will have cylinder dimensions of 350 mm bore by 1,550 mm piston stroke, and a maximum continuous power of 870 kW/cylinder at 167 rev/min (see table below). The Mitsubishi UEC40LSE, Wärtsilä RT-flex40 and Wärtsilä RTA40 will have cylinder dimensions of 400 mm bore by 1,770 mm piston stroke, and a maximum continuous power of 1,135 kW/cylinder at 146 rev/min. All these engine types will be available with five to eight cylinders, so that the UEC35LSE, RT-flex35 and RTA35 will cover an overall power range of 3,475 to 6,960 kW at 142–167 rpm, while the UEC40LSE, RT-flex40, and RTA40 will cover an overall power range of 4,550 to 9,080 kW at 124–146 rpm.

The Wärtsilä RT-flex35 and RT-flex40 engines will incorporate the latest common-rail technology with full electronic control of fuel injection and exhaust valve operation. The RTA35, UEC35LSE, RTA40 and UEC40LSE will have traditional mechanically driven camshafts with fuel injection pumps, exhaust valve actuator pumps, etc. Otherwise both versions will have the same principal characteristics and design features.

The Wärtsilä RT-flex and RTA engines will be manufactured by Wärtsilä’s licensees while the Mitsubishi UEC-LSE engines will be produced by Mitsubishi and its licensees.

Principal particulars of new Mitsubishi and Wärtsilä small-bore low-speed engines:

Engine type RT-flex35
RTA35/UEC35LSE
RT-flex40
RTA40/UEC40LSE
Cylinder bore, mm 350 400
Piston stroke, mm 1,550 1,770
Power/cylinder, MCR, kW 870 1,135
Speed range, rpm 167-142 146-124
Brake mean effective pressure, BMEP, bar 21.0 21.0
Mean piston speed, m/s 8.6 8.6
Number of cylinders 5 to 8 5 to 8
Power range, kW 3,475-6,960 4,550-9,080

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About Wärtsilä Corporation
Wärtsilä enhances the business of its customers by providing them with complete lifecycle power solutions. When creating better and environmentally compatible technologies, Wärtsilä focuses on the marine and energy markets with products and solutions as well as services. Through innovative products and services, Wärtsilä sets out to be the most valued business partner of all its customers. This is achieved by the dedication of more than 17,000 professionals manning 160 Wärtsilä locations in 70 countries around the world. Wärtsilä is listed on The Nordic Exchange in Helsinki, Finland.
www.wartsila.com