The introduction of the electronically controlled camless low speed diesel engine, which is now gaining momentum, is a milestone in diesel technology that deserves a place in history since Rudolf Diesel's first engine. The main purpose of changing from the cam driving to electronic control is to ensure a precise fuel injection timing and rate, as well as the exhaust valve timing and operation, exactly when and as desired. The electronic control of the engine fuel injection and exhaust valves improves low-load operation, engine acceleration, and give better engine load balance and load control, leading to longer times between overhauls, also by implementation of enhanced diagnostics systems, It will give lower fuel consumption and lower cylinder oil consumption, particularly with regard to visible smoke and NOx.
MAN Diesel A/S, one of the designer of 2-stroke, low speed diesel engine, had developed the electronic engine, ME by combining traditional, proven technologies with this new technology of electronically controlled camless low speed diesel engine.
However, it has not been yet proven clearly that the electronically controlled engine has the better characteristics of vibration than the conventional cam driving diesel engine, although the advantage of electronic engine, ME is quite comprehensive. This paper will cover the comparison of torsional vibration aspect between the MAN 12K98MC-C conventional and MAN 12K98ME-C electronic engine, using the measured combustion pressure of cylinder at shop test trial. The gas harmonic data are derived and analyzed from those combustion pressure and compared with the MAN's officially issued harmonic data.