Wärtsilä and Mitsubishi announce new, smaller low-speed marine engines

Wartsila Corporation
  • Trade press release
8 September 2008 at 10:00 AM E. Europe Standard Time

Wärtsilä introduces two new low-speed marine diesel engines at the Wärtsilä Licensees Conference held this week in Lucerne, Switzerland. The engines are developed in co-operation with Mitsubishi Heavy Industries Ltd in Japan, taking advantage of the strengths of both companies with these types of engines. This project comes under the strategic alliance between Wärtsilä and Mitsubishi agreed in September 2005.

The power range of the new engines is 3500–9000 kW. They have cylinder bores of 350 and 400 mm, and each is available as Wärtsilä RT-flex electronically-controlled common-rail engines and Wärtsilä RTA mechanically-controlled engines. Based on the RTA engine designs, Mitsubishi Heavy Industries Ltd will develop UEC-LSE series engines.

The new engines extend the low-speed engine range available from Wärtsilä to lower powers for many types of small and medium-sized commercial vessels. They are designed to give the best powers and speeds for a wide variety of ship types, such as handysize bulk carriers and 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 newbuildings from shipyards in East Asia, especially China, Korea, Japan and Vietnam.

Designed for future environmental challenge

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

Latest common rail-technology

The Wärtsilä RT-flex35, Wärtsilä RTA35 and Mitsubishi UEC35LSE engine types have cylinder dimensions of 350 mm bore by 1550 mm piston stroke, and a maximum continuous power of 870 kW/cylinder at 167 rev/min (see table below). The Wärtsilä RT-flex40, Wärtsilä RTA40 and Mitsubishi UEC40LSE have cylinder dimensions of 400 mm bore by 1770 mm piston stroke, and a maximum continuous power of 1135 kW/cylinder at 146 rev/min. All these engine types will be available with five to eight cylinders, so that the RT-flex35, RTA35 and UEC35LSE cover an overall power range of 3475 to 6960 kW at 142–167 rpm, while the RT-flex40, RTA40 and UEC40LSE cover an overall power range of 4550 to 9080 kW at 124–146 rpm.

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

The first 350 mm-bore engine, an RT-flex type, is planned to be delivered in the first quarter 2011. The first of the 400 mm-bore type will follow twelve months later. 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.

Wärtsilä Licensees Conference

Wärtsilä’s Licensees Conference is being held in Lucerne, Switzerland. Some 70 representatives of the Wärtsilä family of 17 low-speed engine licensees from eight countries are taking part. They are discussing the further development of Wärtsilä low-speed two-stroke engines to meet the market needs of ships today and into the future.

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

 Engine type  RT-flex35
 Cylinder bore, mm: 350 400
 Piston stroke, mm: 1550  1770
 Power/cylinder, R1 MCR, kW: 870  1135
 Speed range, R1–R3, rpm:  167–142  146–124
 Brake mean effective pressure, BMEP at R1, bar: 21.0 21.0
 Mean piston speed at R1, m/s: 8.6 8.6
 Number of cylinders: 5 to 8 5 to 8
 Power range, R2–R1, kW:  3475–6960  4550–9080


Media contacts:
Mr Martin Wernli
Wärtsilä Switzerland Ltd
Direct tel: +41 52 262 2686
e-mail: martin.wernli@wartsila.com

Ms Marit Holmlund-Sund
Public Relations Manager
Wärtsilä Corporation
Direct tel: +358 10 709 1439
e-mail: marit.holmlund-sund@wartsila.com
Internet: www.wartsila.com

Mr Tomoo Kuzu
Senior Manager, Marine Diesel & Machinery Business Section
Mitsubishi Heavy Industries Ltd
Direct tel: +81-3-6716-3383
e-mail: tomoo_kuzu@mhi.co.jp
Internet: www.mhi.co.jp


Wärtsilä in brief
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.


Mitsubishi in brief
Mitsubishi Heavy Industries Ltd is one of the world’s leading shipbuilders and also a major supplier of a wide-range marine machinery such as diesel engines, turbines, boilers, propellers, deck machinery etc., covering high-, medium-, and low-speed diesel engines, with the related services, for various type of vessels. For the power generation market, Mitsubishi delivers power plant solutions from 1 to 1200 MW. In addition Mitsubishi has high-level independent research and development centres with more than 2,000 qualified researchers who assist the development and design of the wide range of various products. Mitsubishi’s net sales totalled Japanese Yen 3,200 billion (approx. EUR 20.0 billion) in fiscal year of 2007 and it has 33,000 employees.
For the low-speed engines, Mitsubishi has been a licensee of the Sulzer and Wärtsilä types since 1925, and has been the designer of UE engines for some 50 years as well, enjoying the customers’ reputation on its products.