• Journal of Power System Engineering
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• v.12 no.2
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• pp.5-11
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• 2008

An analytical study was performed to have temperature and thermal stress distribution on a piston with the change of the 2nd land length of a piston and the existence of knocking in a cylinder. The result showed that the temperature on the skirt region was about $4\sim10^{\circ}C$ higher than that on the pin region. However the thermal stress on the skirt region was about 4MPa lower than on the pin region. It may be due to the higher heat release rate on the pin boss than on the skirt. The result regarding the variation of the 2nd land length of the piston showed that the temperature distribution on the piston was getting lower and the thermal stress distribution was getting higher as the 2nd land length of the piston was shorter.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.105-113
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• 2000

In order to clarify the final process of oil consumption, the distribution and flow of oil through each ring were visualized by induced fluorescence method. Motoring and firing test were performed in a single cylinder research engine with transparent cylinder liner. The appropriate calibration techniques were used to solve the unstability of induced light intensity as well as to know the relation of the oil film thickness and output signal. Oil behavior was also observed at dynamic state by high speed CCD camera. By analyzing the oil film thickness converted from the photographed image, it was observed that the main route of oil transport through each ring is the end gap under the usual operating condition, low engine speed and low load condition. Oil film thickness is observed to be irregular and tend to move in a body horizontally at a given piston land. And it is also found that oil flows through oil ring gap so quickly that it can be observed in a single cycle, but it flows so slowly through top and 2nd compression rings that it takes quite a long time to detect the flow.