4.1.3　Excellent fuel economy and reduced exhaust noxious component

(1)　Increasing combustion pressure, shorter injection time by adopting high pressure type injection pump, optimum matching of the combustion chamber contour with the injection system and introduction of the air cooling type high efficiency turbocharger make it possible to reduce fuel consumption.

(2)　By introducing the result of our long time study on improvement of combustion in regard to compression ratio, combustion chamber and fuel injection system and use of air flow, we could keep NOx to the low level while maintaining low fuel consumption. It is also possible to meet the regulation of IMO.

IMO NOx limit for YANMAR N series engines in 1998

Table　4

4.1.4　Low vibration, low noise

(1)　Engine vibration is kept low by means of reduced weight in the reciprocating motion part and improvement of balance ratio.

Fig　3

(2)　Vibration and noise is kept low because rigidity is increased while making weight lighter by arranging optimum rib for the cylinder block and gear case.

(3)　In particular, specifications for the coupling to the single bearing generator through the flywheel housing and the directly mounting with anti-vibration rubber mounts are prepared for model 6N18(A)L so that vibration transfer to the hull can be protected and at the same time ill effects to the standby engine from the hull can be avoided.

Fig　4

Table　5

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