박용엔진 피스톤 스커트 프로파일 변경에 의한마찰손실(FMEP) 저감 연구
Friction Power Loss Reduction for a Marine Diesel Engine Piston
0
조회
0
다운로드
1
인용
0
참고문헌
키워드
초록
The piston of a marine diesel engine works under severe conditions, including a combustion pressure of over 180 bar, high thermal load, and high speed. Therefore, the analyses of the fatigue strength, thermal load, clamping (bolting) system and lubrication performance are important in achieving a robust piston design. Designing the surface profile and the skirt ovality carefully is important to prevent severe wear and reduce frictional loss for engine efficiency. This study performs flexible multi-body dynamic and elasto-hydrodynamic (EHD) analyses using AVL/EXCITE/PU are performed to evaluate tribological characteristics. The numerical techniques employed to perform the EHD analysis are as follows: (1) averaged Reynolds equation considering the surface roughness; (2) Greenwood_Tripp model considering the solid_to_solid contact using the statistical values of the summit roughness; and (3) flow factor considering the surface topology. This study also compares two cases of skirt shapes with minimum oil film thickness, peak oil film pressure, asperity contact pressure, wear rate using the Archard model and friction power loss (i.e., frictional loss mean effective pressure (FMEP)). Accordingly, the study compares the calculated wear pattern with the field test result of the piston operating for 12,000h to verify the quantitative integrity of the numerical analysis. The results show that the selected profile and the piston skirt ovality reduce friction power loss and peak oil film pressure by 7% and 57%, respectively. They also increase the minimum oil film thickness by 34%.
Abstract
The piston of a marine diesel engine works under severe conditions, including a combustion pressure of over 180 bar, high thermal load, and high speed. Therefore, the analyses of the fatigue strength, thermal load, clamping (bolting) system and lubrication performance are important in achieving a robust piston design. Designing the surface profile and the skirt ovality carefully is important to prevent severe wear and reduce frictional loss for engine efficiency. This study performs flexible multi-body dynamic and elasto-hydrodynamic (EHD) analyses using AVL/EXCITE/PU are performed to evaluate tribological characteristics. The numerical techniques employed to perform the EHD analysis are as follows: (1) averaged Reynolds equation considering the surface roughness; (2) Greenwood_Tripp model considering the solid_to_solid contact using the statistical values of the summit roughness; and (3) flow factor considering the surface topology. This study also compares two cases of skirt shapes with minimum oil film thickness, peak oil film pressure, asperity contact pressure, wear rate using the Archard model and friction power loss (i.e., frictional loss mean effective pressure (FMEP)). Accordingly, the study compares the calculated wear pattern with the field test result of the piston operating for 12,000h to verify the quantitative integrity of the numerical analysis. The results show that the selected profile and the piston skirt ovality reduce friction power loss and peak oil film pressure by 7% and 57%, respectively. They also increase the minimum oil film thickness by 34%.
참고문헌 (17)
- Design and application of composite piston for high power diesel engine, "Son, J.", SAE, ~, pp.SAE Technical Paper 2009-01-0192 (2009)
- 손정호, "박용 디젤엔진용 분리형 피스톤의 내구설계", 대한기계학회논문집 A, 34(5), pp.651~657 (2010), 대한기계학회
- John B. Heywood, "Internal Combustion Engine Fundamentals, McGRAW-HILL International" (1988), Automotive Technology Series
- Paul Herster, "Powertrain Efficiency Enhancement -Mechanical Friction Analysis", Hybrid Drive Applications, 2009, ~
- Son, J. H., "EHD Analysis and fretting damage prediction of marine engines’s connecting rod", Proceedings of the KSTLE 2011 Spring Conference, pp.53~54 (2011)
- An, S. C., "The durlbility evaluation for connecting rod of high speed diesel engine", Proceeding of KSME 2012 Spring Conference, pp.303~306 (2012)
- Bernard J. Hamrock, "Fundamentals of fluid film lubrication" (2004), Marcel Dekker, Inc
- Nadir. Patir, "Application of average flow model to lubrication between rough sliding surfaces", Transactions of the ASME, 101, pp.220~230 (1979)
- Greenwood, J. A., "The contact of two nominally flat rough surfaces", Proceedings Institution Mechanical Engineers, 185 (1970)
- Design and application of composite piston for high power diesel engine, "Son, J.", SAE, ~, pp.SAE Technical Paper 2009-01-0192 (2009)
- John B. Heywood, "Automotive Technology Series" (1988), McGRAW-HILL International
- Paul Herster, "Powertrain Efficiency Enhancement -Mechanical Friction Analysis", Hybrid Drive Applications, 2009, ~
- Son, J. H., "EHD Analysis and fretting damage prediction of marine engines’s connecting rod", Proceedings of the KSTLE 2011 Spring Conference, pp.53~54 (2011)
- An, S. C., "The durlbility evaluation for connecting rod of high speed diesel engine", Proceeding of KSME 2012 Spring Conference, pp.303~306 (2012)
- Bernard J. Hamrock, "Fundamentals of fluid film lubrication" (2004), Marcel Dekker, Inc
- Nadir. Patir, "Application of average flow model to lubrication between rough sliding surfaces", Transactions of the ASME, 101, pp.220~230 (1979)
- Greenwood, J. A., "The contact of two nominally flat rough surfaces", Proceedings Institution Mechanical Engineers, 185 (1970)