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Engine oil consumption must be reduced for lowering particulate matter, deterioration of engine after treatment devices and users running cost. A lot of factors affect engine oil consumption, and it is usually estimated experimentally on very latter stage of engine development. Therefore calculation method for oil consumption which can be used for engine design is required. Supply oil volume is necessary to calculate oil consumption. In this study, oil pressure distribution under the oil ring which affects supply oil volume was measured, and a hypothesis for generating oil pressure was discussed. Oil pressure was deviated from crank case pressure and a pressure rise under the oil ring was found in the latter half of the piston down strokes. The maximum pressure was measured at the center of the piston skirt under the oil ring. It was showed that oil pressure rise could be simulated considering distribution of oil film thickness on the cylinder wall.

An increase in lubricating oil consumption in an engine causes an increase in particulate matters in exhaust gases, poisoning the catalyst of after treatment devices, abnormal combustion in a turbo-changed gasoline engine and so on. Recent trend of low friction of a piston and piston ring tends to increase in lubricating oil consumption. Therefore reducing oil consumption is required strongly. It is known that oil pressure generated under the oil ring affects lubricating oil consumption. It is also known that the position of oil drain holes affects lubricating oil consumption. In this study, the effect of the position of oil drain holes on oil pressure under the oil ring and lubricating oil consumption was investigated. The oil pressure under the oil ring is measured using fiber optic pressure sensors and pressure generation mechanisms were investigated. Lubricating oil consumption was also measured using sulfur tracer method and the effects of oil drain holes against the oil pressure under the oil ring were evaluated. Four types of arrangement of oil drain holes were tested. The oil pressure variations under the oil ring in the circumferential direction was measured using a gasoline engine. An increase in oil pressure was found during down-stroke of the piston. The lowest oil pressure was found for the piston with four oil drain holes. Two holes nearby the front / rear end of the piston skirt showed relatively lower pressure. The measured results of oil consumption showed good agreement to measured oil pressure under the oil ring. It was found that oil pressure under the oil ring affected oil consumption, and oil drain holes set near the front / rear end of the piston skirt were effective for reducing oil consumption.

Microwave has been often used for nano-particle synthesis because rapid growth and mono-dispersed particle size are obtained. However, superheat behavior causes larger bubble size and disorders temperature distribution when higher power of microwave is irradiated. Accordingly, superheat must be prevented for stable operation of nano-particle process. In previous study, we found that bubble formation happened during particle formation at the same time when FeCl 3 aqueous solution is heated by microwave. According to the results through in-situ particle size measurement during the irradiation, superheat behavior occurred at the condition of the higher power and lower suspension density. In this study, ethylene glycol with lower electric constant was added to promote particle nucleation and to enlarge particle number density. Moreover, the solute is not dissolved in ethylene glycol as anti-solvent although ethylene glycol is dissolved in water. The results showed that bubble size during the irradiation and particle size after the irradiation became smaller by the ethylene glycol addition. As a result, operation by higher power became possible, and higher particle number density was obtained as synergy effect of anti-solvent effect and quick thermal response by microwave. Finally, addition of alcohol became good method for nano-particle formation process to prevent superheat behavior during higher power irradiation.

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