Speed irregularity characteristic of low speed, two-stroke marine diesel engine applied as vessel's main propulsion

• Autorzy: Kowalak P.
• Języki publikacji: EN

Abstrakty

EN

The piston engine irregularity is a consequence of the uneven power supply from the engine units. As such, it contains valuable information about engines units working process. Unfortunately, it is strongly influenced by torsional vibration, resonance, and propeller behaviour. In order to better understand the speed irregularity phenomena the instantaneous speed was recorded and its characteristic against engine mean speed was developed. Some statistical parameters: standard error and deviation as well as variance were determined. The results were compared with propulsion plant torsional vibration. The presented results show that the irregularity of the long stroke engine's speed is strongly influenced by torsional vibration phenomena. The analyzed engine has a bared speed range 37-43 rpm. Exactly around that range, the speed irregularity reaches its maximum values of 18% of mean speed. The analysis can be considered as qualitative look into the phenomena. However even based on the presented analysis one can observe some practical inferences. The common type of electronic indicators is used to simplify the measurement by assuming that the shaft speed is equal in between the pickup pulses. In order to increase the accuracy of the indicated power determination the use of such instrument should be avoided in the speed range, which is a multiple number of the barred speed. Due to the fact that the shaft speed is irregular especially in the ranges where torsional resonance may occur the piston positioning (for example for TDC determination) purpose procedure should take it into account.

Słowa kluczowe

EN

transport; marine diesel engines; combustion processes; speed measurement; speed irregularity

• Wydawca: Łukasiewicz Research Network - Institute of Aviation ; European Science Society of Powertrain and Transport KONES Poland ; Wydawnictwo Instytutu Technicznego Wojsk Lotniczych
• Czasopismo: Journal of KONES
• Rocznik: 2008
• Tom: Vol. 15, No. 4
• Strony: 263--268
• Opis fizyczny: Bibliogr. 8 poz., rys.

Twórcy

autor

Kowalak P.

• Maritime University of Szczecin - Department of Engineering Waly Chrobrego 1-2, 70-500 Szczecin, Poland tel.: + 48 91 4809400, fax: [phone],

Bibliografia

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• [3] Germanischer, L., Rules for Classification and Construction,I - Ship Technology, Part 1 - Seagoing Ships,Chapter 2 - Machinery Installations, Edition 2000.
• [4] Heywood, John. B., Internal Combustion Engines Fundamentals, McGraw-Hill International Editions, Singapore 1988.
• [5] Larsen, O. C., Søntvedt, T., Prevention of Harmful Engine - and Propeller - Induced Vibrations in the Afterbody of Ships., Det Norske Veritas Information No. 9, Oslo, August 1972.
• [6] MAN B&W Diesel A/S, Vibration Characteristics of Two - stroke Low Speed Diesel Engines 2nd edition revised from P. 8703-165, Copenhagen 1988.
• [7] Pitak, A., Olchowik, W., Trawiński, G., Analiza możliwości wykorzystania pomiarów chwilowej prędkości obrotowej wału korbowego do oceny stanu technicznego silnika, XXX Jubileuszowe Ogólnopolskie Sympozjum Diagnostyka Maszyn, Węgierska Górka 2003.
• [8] Wimmer, A., Glaser, J., Indykowanie silnika, Warszawa, Instytut Zastosowań Techniki rozdział 9, s. 17-24 2004.