Adaptive control of marine engines in heavy weather and ship manoeu vres

Project Information

ACME

Grant agreement ID: BRPR950091

Project closed

Start date 1 January 1996

End date 31 October 1999

Funded under

• Specific research and technological development programme in the field of industrial and materials technologies, 1994-1998

Total cost € 0,00

EU contribution No data

Coordinated by

DANAOS SHIPPING CO.
Greece

Exploitable results

Adaptive Control of Marine Engines in Heavy Weather and Ship Manoeuvers (ACME)

Speed control of the single, large, directly coupled Diesel engine used for propulsion of commercial vessels, is nowadays achieved by use of electronic governors which implement the PID control law. Although these devices handle successfully engine running under normal conditions, there maybe cases, when the ship is sailing in heavy weather, where power/speed reduction is required for engine safety reasons. Especially, in operation of ships in heavy seas, the load demand on the propulsion engine from the propeller may change rapidly, causing significant deviations of the shaft rotational speed from the desired setpoint. Since such deviations, especially to the overspeed side, can activate limiter protection, engine speed reduction is required. If this occurs often it may result in underutilization of the powerplant. Answering to this need, the transnational ACME project (Adaptive Control of Marine Engines) was initiated, aiming to develop methods of improved control, allowing for full exploitation of the main engine power under extreme weather conditions. The methodology of the ACME project has been to develop a system for propeller load prediction a few seconds ahead in time, which could provide a driving signal to an engine control unit, that would decrease fuel temporarily in case of an imminent expected load sink, thus escaping excessive overspeed. Based on the analysis of a large number of specially conducted systematic tests of a container hull-form in rough sea conditions in a model basin, certain patterns of instantaneous torque demand have been identified. Then, after extensive simulation studies of engine operation, a first version of the load prediction system has been implemented. This version requires as input the vertical aft ship acceleration and the propeller load history. A new powerplant control unit has also been developed, which uses as additional input the signal of the load prediction system. The prototype system has been installed on-board a containership, and after a complete set of sea trials for safety assessment, has been tested in actual operating conditions for a period of several months. The data series collected from the full-scale tests further show that it may be possible to simplify the load prediction system to a version which would require only the propeller load history as input. Conclusively, the ACME project demonstrated that the use of model-based adaptive control may extend propulsion plant capabilities, especially under heavy weather conditions, enabling smoother and more reliable engine running.