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The Effect of Crankshaft Offset on Piston Friction Force in a Gasoline Engine
Technical Paper
2000-01-0922
ISSN: 0148-7191, e-ISSN: 2688-3627
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Sector:
Event:
SAE 2000 World Congress
Language:
English
Abstract
Offsetting the crankshaft axis with respect to the cylinder axis has been thought to be a method to reduce piston side force[1]. Hence the piston friction is expected to be reduced. An automotive manufacturer has already used the crankshaft offset for a production gasoline engine to improve fuel economy. The authors have conducted research into the effect of crankshaft offset on the piston friction.
A single-cylinder engine was modified to have a crankshaft offset. Piston frictional force was measured in real-time by using a floating liner method. In addition, laser-induced fluorescence (LIF) technique was employed to measure oil film thickness on the piston skirt area, and a gap sensor was used to measure piston motion. As a result, the authors concluded that the effect of crankshaft offset on piston friction could not be explained only by its effect on the piston side force. In accordance with the measurement results, crankshaft offset changed piston slap motion. Hence, the conditions of piston skirt contact and oil film development changed in addition to the change in the piston side force and affected the piston friction characteristics.
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Citation
Nakayama, K., Tamaki, S., Miki, H., and Takiguchi, M., "The Effect of Crankshaft Offset on Piston Friction Force in a Gasoline Engine," SAE Technical Paper 2000-01-0922, 2000, https://doi.org/10.4271/2000-01-0922.Also In
References
- Kumabe Kazuo “Nainenkikangaku” 185 188
- Sano Shinichi et al. “Improvement of thermal efficiency by offsetting the crankshaft center to the cylinder bore center” SAE of Japan 1996
- Furuhama Shoichi Takiguchi “Measurement of Piston Frictional Force In Actual Operating Diesel Engine” SAE Paper 790855 1979
- Takiguchi Masaaki et al. “Effect of Slap Noise on Piston and Cylinder Deformation” SAE of Japan 1990
- Takiguchi Masaaki et al. “Variation of Piston Ring Oil Film Thickness in an Internal Combustion Engine” SAE Paper 980563 1998