4.4 Overhaul procedure

The overhaul procedure and the weights of the main components of the MET90SE are shown in Fig.15. The overhaul procedure is the same as for previous MET turbochargers. The weights of components to be broken down have been limited, and the use of efficient special tools allows comparatively easy on-board turbocharger overhaul.

　

Fig.15 Overhaul procedure of MET90SE turbocharger

　

4.5 Test results

4.5.1 Performance

Independent miming tests were performed on the MET90SE incorporating the maximum capacity JV3L impeller wheel as well as maximum capacity 7K2 blades. Turbocharger overall efficiency as determined by these tests is shown in Fig.16. Maximum efficiency of 72% was obtained.

　

Fig.16 Turbocharger efftciency of MET90SE

　

4.5.2 Noise

In order to improve the shipboard environment, it is desirable to achieve reductions in the noise levels of main engine turbochargers (which are the main sources of noise). Fig.16 illustrates the noise level of the MET90SE turbocharger. At a level of 8,000 rpm (or compressor pressure ratio of 3.3) for the turbocharger, which can be considered to be in the normal engine load range, sufficiently low noise of about 100 dB is achieved.

　

Fig.17 Noise level of MET90SE turbocharger at Test bench

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