Changes in Wear-Preventing Property of Deteriorated Engine Oils
| Project/Area Number |
02650109
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
機械要素
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| Research Institution | Institute of Industrial Science, University of Tokyo |
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Principal Investigator |
KIMURA Yoshitsugu Univ. of Tokyo, Inst. Industrial Science, Professor, 生産技術研究所, 教授 (20010910)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1991: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1990: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Lubricating oil / Deterioration / Wear / Silicon nitride / エンジン油 / 劣化油 / モデル劣化油 |
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| Research Abstract |
Engine oils which serve for reducing friction and wear under severe conditions gradually deteriorate owing to oxidation, nitration, thermal decomposition, contamination and additive depletion. This project aims at clarifying effects of the deterioration of engine oils on their wear-preventing property. A series of experiments on friction and wear of steel and silicon nitride are conducted in the oils deteriorated with use in gasoline engines, oils containing model deterioration products, etc. The following conclusions are obtained.
(1)Wear-preventing property of engine oils significantly changes with the degree of deterioration in gasoline engines.
(2)The increase in total acid 'number above the initial value has a definite correlation with the amount of wear of steel. With the increase in it, the amount of wear first decreases slightly, but increases sharply when it exceeds a certain threshold.
(3)With small amounts of addition, all model deterioration products studied improve wear-preventing property of the engine oil with steel, but their addition in large amounts increases the amount of its wear. This trend is common to that found with the deteriorated engine oils.
(4)The effect of formic acid, a combustion product of methanol, is qualitatively the same as higher fatty acid on the wear of steel, but similar effects appear at less contents.
(5)Changes in wear of silicon nitride with the addition of model deterioration products are generally similar to those of steel except for larger wear caused by water.
(6)Water causes high friction and wear of silicon nitride under high loads and/or low sliding speeds, while tribochemical dissolution of silicon nitride with water makes smooth wear scars resulting in low friction and minimized wear. The transition condition between these two regimes depends on the forms of the presence of water.
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Report
(3 results)
Research Products
(8 results)
