Which method (on the design) do you think necessary to reduce NOx by 40% and improve (fuel consumption) again in future?
[Answer]
1. The objective oil is A-oil. (It is additionally described in the text together with the analysis result.)
2. The compression ratio was changed by the length of the connecting rod, and the shape of the combustion chamber was not changed. (It is additionally described in the text.)
3. I understand your question is on 7]In Fig.7. NOx was reduced from 4]through 9](change of the overlap period),11](change of the inlet valve closing timing), and 12](re-increase of the charged air pressure), and the fuel consumption and the exhaust gas temperature in this condition were same as those in 1].
Though NOx can be reduced only by the normally retarded fuel injection timing and the increase of the charged air pressure, the fuel consumption is remarkably degraded. To eliminate this, it is believed important to change the opening closing timing of the inlet/exhaust valve.
Questioner： Mitsugu Kimura, Makita
[Question]
When the number of injection holes of the fuel atomizer is changed from 10 to 14, is the angle of injection holes constant, or stepped?
[Answer]
The angle of injection holes in the case of 14 holes is same as the case of 10 holes, while in the case of 2-row 14-hole type (7 holes for each row), the second row is added on the inner side.
The 14-hole atomizer in the text is the atomizer of 14-hole in one row. (It is additionally described in the text.)
Questioner： Tatsuo Mizunuma, Matsui Iron Works
[Question]
Is the measuring instrument of NOx based on the CLD method?
[Answer]
Yes, it is based on the CLD method.
Message：
Based on the tests in this report, and the confirmatory tests with the actual engines which are successively carried out, the outlook is in sight in which the IMO regulation 2000 can be approximately satisfied only by changing the design factors of the engine.
Strenuous efforts will be made on the development of the method to cope with the regulation which will be more stringent every five years, including the economical aspect.
References
1) T. Nagai, et al., Journal of the MESJ, Vol.25, No5, 306 (1990)
2) H.Ohnishi, et al., Journal of the MESJ, Vol.29 No.3,247 (1994)
3) K.Sonoda, et al., Journal of the MESJ, Vol.29, No.6 422 (1994)
