Electronically-controlled developments

In a market not renowned for its hyperbole, it is undoubtedly significant that a head of one of the largest manufacturers of slow speed marine diesel engines should hail the launch of a new engine as: “…the greatest step forward in the technology of large marine diesel engines since the introduction of turbocharging of such large two-stroke engines in 1952”.

The fact that the development to which he referred had occupied a fair proportion of his R&D budget over the preceding 12 years, and had used up some 200-man-years of expertise, probably helped swell the emotion of the moment. Nevertheless, the fact that the market has already responded in positive terms to the onward application of electronically-controlled engine management with other engine types and makes adds credence to the comments of Peter Sunn Pedersen, executive vice president of MAN B&W Diesel A/S.

Specifically, the ME concept to which Pedersen referred, is a development by MAN B&W Diesel engineers of fully integrated electronic control of the engine. Such control seeks to achieve optimal fuel injection timing and rate, as well as ensuring the exhaust valve timing and operation occur exactly when, and as, desired. Essentially, the traditional simplicity and safety of the engine function is retained, with the benefit of improved emission characteristics, potentially lower operating costs, and a very high degree of flexibility relating to various operating modes ? in particular, to the optimisation of part load characteristics.

The advantages of such a system have led much of the R&D thinking in other elements of the slow speed market, such as at the Wärtsilä Corporation, where the development of the Sulzer RT-flex engines have been hailed in their own right as the first low-speed engines to have electronically-controlled common-rail systems for fuel injection and valve actuation. Originally seen in the bulk carrier Gypsum Centennial, which entered service in 2001 with the first production Sulzer RT-flex engine, the 6RT-flex58T-B engine has now run for more than 7,500 hours, giving the Wärtsilä engineers ample opportunity to monitor the expected benefits of smokeless operation, much lower steady running speeds (especially useful for canal transits and harbour approaches), reduced fuel consumption and lower maintenance requirements.

Both MAN B&W and Wärtsilä report positive market responses with preliminary orders covering 50, 60, 70 and 98cm cylinder sizes and up to 68,640kW for each of the respective engine builders.

In a separate development of IT in slow speed engine management, Mitsubishi UE Engines introduced an engine diagnostic system, ?Doctor Diesel? for its UEC 68LSE Series engine. The system is designed to carry out many different diagnostic and monitoring functions including the integration of cylinder liner temperature monitoring devices. Additionally, MHI has developed a number of high-precision analysis tools ? including a cylinder internal combustion simulator and a main bearing configuration analyser ? to raise the design reliability levels, particularly in 3D-CAD environments.

Perhaps the last word should once again be given to Pedersen as he enthusiastically reflects on the way forward for the two-stroke market: “We are now seeing the realisation of our long-term vision ? the Intelligent Engine ? an engine with the capability to monitor itself to ensure the highest possible reliability and lowest possible running costs, while minimising repair and maintenance functions; an engine which also minimises emissions as well as fuel and lube oil consumption; and, a highly flexible engine in terms of operating modes which, significantly, can also be updated during the whole of its 25-30 year lifespan.”