It’s long been known that a close relationship between OEMs and their clients is of great importance. Such relationship and cooperation might be even more important during development of new products and the testing of new components and systems.
MAN Diesel has what could be calleda floating test bed in the 37 500 dwt chemical tanker Bow Cecil. The vessel, owned by the Norwegian company Odfjell, has played a key role in the development of MAN Diesel’s electronically controlled ME concept for twostroke engines.
Since November 2000, ME components have been tested in Bow Cecil’s six-cylinder MAN B&W L60 main engine. The engine was originally installed as a mechanically controlled L60MC engine and later, the 60 cm bore model was converted to an L60ME-C configuration. In this, the engine was equipped with electronic control of the fuel injection and exenables valve systems. The camshaft, however, was kept, which enabled operation either in ME or MC mode a fairly distinctive feature.
In 2008, a new agreement was signed between Odfjell and MAN Diesel covering a further modification of the engine, now from the L60ME-C version into the latest L60ME-B specification. The electronic fuel injection exenables the ME-B engine to meet the IMO Tier 2 NOx emissions as well as other national and regional environmental requirements.
The first step of the project execution was carried out in October 2008 at the ASRY’s shipyard in Bahrain, where all ME-related components were removed except for the ME fuel boosters. It was followed by a completion in early August 2009 at a lay-by berth in Rotterdam, Netherlands, only requiring one day off-hire and subsequently at sea.
During the second part of the project, the original engine control system was retrofitted with an ME-B system, and two operating panels were installed in the engine control room with required
cabling also carried out there. Since the original MC camshaft was retained for the ME-B configuration, the ME control valves and actuators for the exhaust valves were removed and
sealed off, and new control valves for the fuel booster were fitted. An upgrading of the capacity of the two original start-up electrohydraulic pumps from 45 to 65 kW was also completed.
The ME-B configuration utilizes hydraulic swashplates to control the pressure of the hydraulic oil; this required an ME-B type hydraulic control block to be installed. Some refinement of the existing pneumatic control system was also carried out, enabling the ME-B control system to better interface to the engine. The fuel injection is performed by one fuel booster per cylinder, similar to the established ME engines. The pressure boosters are mounted on hydraulic cylinder units, one per unit. The hydraulic cylinder unit is equipped with one electronic fuel
injection valve and a booster unit. The ME hydraulic blocks are retained and the hydraulic oil is supplied to the units via a single, double-walled, oil pipe above the camshaft housing.
Hydraulic power for the fuel boost boosters is secured by two electrically driven pumps at the engine front end. In the event of one pump failing, 80% engine power would still be available.
The engine was further fitted with the alpha lubricator system mounted separately on the second gallery. It has its separate oil supply system like the standard alpha lubricator system. The project shows that an engine already fitted with an alpha lubricator system does not need much rebuilding to fit into the ME-B system.
“The experience we have gained from the Bow Cecil project is valuable for our PrimeServ group, enabling them to offer ME-B conversions to operators of ships with appropriate MC engines installed,” said Otto Winkel, senior vice president, PrimeServ Copenhagen.