As for the exhaust valve combustion surface, exhaust valve seat and cylinder cover, the maximum measured temperatures were 531℃, 300℃ and 266℃ respectively which are lower than those measured in the existing UEC-LS II series, and the reliability of these parts was confirmed.
2.4 Result of engine main frame stress
Fig.8 shows the measurement results of stresses in the engine main frame. For each point, both static stresses by tightening of the tie bolts and dynamic stresses during operation at 100% load were measured. The stress level is equivalent to those measured in the existing UEC-LS II series engines and the stiffness and the reliability of main frame made of monoblock casting was confirmed.
2.5 Result of engine main frame vibration
Fig.9 shows the measurement results of the engine main frame vibration. The resonance point of the 6 order H-type mode is approx. ±0.20 mm at 91 rpm at the test bed. The amplitude is very small and the reliability was confirmed.
2.6 Result of NOx measurement
Rated engine speed of UEC37LS II at P1 rating is 186 rpm and IMO NOx regulation value is 15.8g/kWh. Fig.10 shows the results of NOx measurement of UEC37LS II and the existing UEC-LS II series engines. The NOx value of UEC37LS n in accordance with E3 test-cycles is 14.6 g/kWh, which is fully complied with IMO NOx regulation. As a result the UEC37LS II at P1 rating can clear the NOx regulation of IMO without the additional NOx reduction methods.
