08-16-2017, 10:33 PM
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ME Engines the New Generation of Diesel Engines
INTRODUCTION
The introduction of the electronically controlled camshaft-less low speed diesel engines, which is now gaining momentum, is a milestone in diesel technology that deserves a place in history like Rudolf Diesel s first engine in Augsburg, the 1912 motor vessel Selandia, the introduction of turbocharging on two-stroke diesels in 1954, and the first SCR (Selective Catalytic NOx Reduction) systems on ships in 1989. This paper will outline how MAN B&W takes advantage of this new technology in its MErange of engines by combining traditional, proven technologies with enhanced electronic control so as to design engines which, while being both production-friendly and operationally easy to handle, yet will provide all benefits to the owner and operator of contemporary and future software achievements. Fig. 1 shows the first such commercial ME-C engine in Frederikshavn, Denmark. Camshaft-controlled diesel engines have been the state of the art ever since the birth of reciprocating machinery and have been refined and developed ever since. However, a mechanical cam is fixed once made and, in spite of various mechanical and hydraulic add-on devices like VIT, etc., timing control possibilities are limited with mechanical cams. Not least fuel injection pressure control and variation over the load range have limitations with a camcontrolled engine. Therefore, the main purpose of changing to electronic control is to ensure fuel injection timing and rate, as well as the exhaust valve timing and operation, exactly when and as desired, see Fig. 2. Especially with respect to the fuel injection rate, also at low load, without the limitation from the camshaft-controlled engine, where this would result in too high pressure at high load. Both the cam angle, inclination and length are electronically variable. In addition, the ME engine features electronic control of the cylinder lube oil feed, by having our proprietary Alpha Lubricators integrated in the system. With the Alpha Lubrication system, about 0.3 g/bhph cyl. oil can be saved, compared with engines with mechanical lubricators. The electronic control of the engine fuel injection and exhaust valves improves low-load operation, engine acceleration, and give better engine balance and load control, leading to longer times between overhauls, also by implementation of enhanced diagnostics systems. It will give lower fuel consumption, lower cylinder oil consumption and, not least, better emission characteristics, particularly with regard to visible smoke and NOx, see Fig. 3 for a summary. For the ME engines, the electronic control system has been made complete. Hence, the ME engine features fully integrated control of all functions like the governor, start and reversing, fuel, exhaust and starting valves, as well as cylinder oil feeding, as summarised
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