New Sulzer common-rail marine engine

Wärtsilä Corporation, Trade press release, 6 March 2003 at 11:00 UTC+2

Wärtsilä Corporation is announcing a new low-speed marine diesel engine which will be available in two versions, the Sulzer RT-flex50C and the Sulzer RTA50C. The Sulzer RTA50C is a joint development with Mitsubishi Heavy Industries Ltd in Japan, taking advantage of the strengths of both companies with this type of engine.

The basis for this joint development is the agreement made between Wärtsilä and Mitsubishi in November 2002.

The first engines of the new type are expected to be completed towards the end of 2004. Both versions will be marketed and manufactured in the normal way by Wärtsilä and its licensees.

The Sulzer RT-flex50C is based on the Sulzer RTA50C. Instead of the traditional mechanically-driven camshaft with fuel injection pumps, exhaust valve actuator pumps and reversing servomotors, the Sulzer RT-flex50C has electronically-controlled common-rail systems for fuel injection and exhaust valve actuation.

The Sulzer RT-flex50C and Sulzer RTA50C have the same principal characteristics, with cylinder dimensions of 500 mm bore by 2,050 mm stroke. Their maximum continuous power is 1,620 kW/cylinder (2,200 bhp/cylinder) at 124 rev/min. Both engines will be available with five to eight cylinders covering an overall power range of 5,650 to 12,960 kW (7,700 to 17,600 bhp) at 99 to 124 rev/min. They thus offer the right powers and speeds for a wide variety of ship types including the new generation of Handymax and Panamax bulk carriers, large product tankers, container feeder vessels and medium-sized reefer ships.

The engines will meet the market needs for outstanding reliability, high efficiency, compactness, optimised industrialisation, and environmental requirements. As with all new marine engines nowadays, they will be fully compliant with the NOx emission regulation of Annexe VI of the MARPOL 1973/78 convention.

The Sulzer RT-flex version has the added benefit of no smoke emissions at all operating speeds, together with lower running speeds. The mechanical version, the Sulzer RTA50C, will be available for those shipowners preferring the traditional concept.

Both versions, RT-flex50C and Sulzer RTA50C, will benefit from the proven Sulzer TriboPack technology for best piston-running behaviour, providing low wear rates for three years between overhauls, and minimum cylinder lubrication oil consumption.

Principal characteristics of
the Sulzer RT-flex50C and Sulzer RTA50C marine diesel engines:


 Cylinder bore:  500  mm
 Piston stroke:  2,050  mm
 Stroke/bore ratio:  4.1  
 Power, R1 MCR:  1,620  kW/cylinder
   2,200  bhp/cylinder
 Speed range, R1-R3  124-99  rev/min
 Mean effective pressure at R1:  19.5  bar
 Mean piston speed at R1:  8.5  m/s
 Maximum cylinder pressure:  155  bar
 Numbers of cylinders  5 to 8  
 Power range:  5,650-12,960  kW
   7,700-17,600  bhp
 BSFC at full-load, R1-R2  165-171  g/kWh
   121-126  g/bhph


Marit Holmlund-Sund
Public Relations Manager, Marine Division
Wärtsilä Corporation
Direct tel: 358 10 709 1941
Direct fax: +358 10 709 1942