The engine protection mode is selected exclusively by the condition monitoring and evaluation system, regardless of the current operating mode. Should this happen under circumstances where, for instance, reduced power is unacceptable for reasons of the safety of the ship, the engine protection mode can be cancelled from the bridge.
The centre of Fig.1 shows the brain of the system: the electronic control system. This analyses the general engine condition and controls the operation of the engine systems shown in the lower part of Fig.1: the fuel injection system, the exhaust valves, the cylinder lube oil system and the turbocharging system.
The control functions for these units are partly pre-optimised functions which may be selected from the bridge, partly functions selected by the engine condition monitoring system on the basis of an analysis of various input from the units on the left and right sides of Fig.1: general engine performance data, cylinder pressure, cylinder condition monitoring data and output from the Load Control Unit. More detailed descriptions of these systems can be found in [1].
The condition monitoring and evaluation system is an on-line system with automatic sampling of all "normal" engine performance data, supplemented by cylinder pressure measurements, utilising the CoCoS-EDS (Engine Diagnosis System). When the data-evaluation system indicates normal running conditions, the system will not interfere with the normal pre-determined optimal operating modes. However, if the analysis shows that the engine is in a generally unsatisfactory condition, for instance if the exhaust gas temperature is too high, general countermeasures will be initiated for the engine as a unit.
In the case mentioned fuel injection may be retarded and/or the exhaust valves may be opened earlier, giving more energy to the turbocharger, thus increasing the air amount and reducing the exhaust gas temperature. At all events, the system reports the unsatisfactory condition to the operator together with a fault diagnosis, a specification of the countermeasures used or proposed, and recommendations for the operation of the engine until normal conditions can be re-established or repairs can be carried out.
The 4T50MX research engine in our R&D Centre in Copenhagen has been operated since 1993 with a first-generation Intelligent Engine (IE) system. The engine has been running with this system in its normal function as a tool for our general engine development, and we have accumulated significant experience with this system. Being the first generation of IE, the system was somewhat 'over-engineered' and relatively costly compared with the contemporary camshaft system. On the other hand, the system offered much greater flexibility, a factor that has proved its value in the use of the research engine as one of our most important development tools.
In 1997, the engine was fitted with second-generation IE systems which have been developed in order to:
・simplify the systems and adapt them to meet the requirements of the engine
・facilitate production and reduce the costs of the IE system
・simplify installation and avoid the use of special systems wherever possible.
On the electronic software/hardware side, the original first-generation system was used for a start. Since then, significant development efforts have been invested in transforming the electronic part of the IE system into a modular system, where some of the individual modules can also be used in conventional engines. This means development of a new computer-unit and large software-packages - both of which have to comply with the demands of the Classification Societies for marine applications.
The new system, replacing the camshaft system of the conventional engine, is illustrated in Fig.2. It consists of an engine-driven high-pressure servo oil system, which provides the power for the hydraulically operated fuel injection and exhaust valve actuation units on each cylinder. Before the engine is started, the hydraulic power system (or servo oil system) is pressurised by means of a small electrically driven high-pressure pump.
