JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS
Online ISSN : 2189-9967
Print ISSN : 0915-1168
ISSN-L : 0915-1168
Volume 65 , Issue 8
Special Issue on Trends in Energy-Saving Lubricant Technology
Showing 1-13 articles out of 13 articles from the selected issue
Announcement
Contents
Serial Messages to Tribologists
Special Issue on Trends in Energy-Saving Lubricant Technology
Explanation
  • ―Comparison between GTL Base Oil and Mineral Oil―
    Kumiko KAMATA
    2020 Volume 65 Issue 8 Pages 471-477
    Published: August 15, 2020
    Released: August 15, 2020
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    The technical requirements to achieve better fuel and energy efficiency via lubricants are growing more severe around the world. Lubricant formulation trends and base oil trends for fuel and energy efficiency are reported in this article. Group III mineral oil and GTL base oil are available in the market in large volumes and also show good properties for fuel and energy efficient lubricants. Especially for low viscosity engine oil, cooling oil for electric vehicle and hydraulic oil, GTL base oils shows good performance because of low volatility, high viscosity index, low density and high heat capacity. Required base oil properties for fuel and energy efficient lubricants and lubricant performance with Group III mineral oil and GTL base oil are reported in this article.

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  • Kenji YAMAMOTO
    2020 Volume 65 Issue 8 Pages 478-484
    Published: August 15, 2020
    Released: August 15, 2020
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    Active technology developments for improving thermal efficiency of internal combustion engine are being carried out to take action to combat climate change. Fuel economy lubricant is one effective technology for improving fuel economy of vehicles, and lowering viscosity is a first approach for this purpose by reducing hydrodynamic resistance of lubricant. On the other hand, low viscosity lubricant generate more boundary contact resistance, and it makes friction modifier more important for reducing friction loss in engines. In this article, the technology related to MoDTC which is popular friction modifier for fuel economy engine oil, will be introduced mainly including combination effect with other components in lubricants and interaction with surface treatments. Recent studies with polymer type friction modifiers which is becoming new group of friction modifiers are also shown. The author believes that improving technology of friction modifiers will contribute to minimize greenhouse gas emission from vehicles, and reduce an impact of our society on climate change which is one of the largest technological challenges that we are facing.

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  • Kazunori YOSHIDA, Hiroki YAMASHITA
    2020 Volume 65 Issue 8 Pages 485-489
    Published: August 15, 2020
    Released: August 15, 2020
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    In recent years, the world has been promoting environmental measures to prevent global warming with the aim of building a sustainable society related to the SDGs. In the automobile industry, which emits large amounts of CO2, measures to reduce the weight of vehicles, improve the fuel efficiency of engines, and shift to hybrid cars and electric vehicles are being promoted as countermeasures. Viscosity modifiers greatly contribute to the high performance of this lubricating oil. This paper introduces VM types, trends, mechanism of action, and our high-performance VMs for engine oil and drive line fluid.

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  • Hiroshi OKI
    2020 Volume 65 Issue 8 Pages 490-497
    Published: August 15, 2020
    Released: August 15, 2020
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    Among the techniques for improving the fuel efficiency of automobiles, improving the efficiency of an internal combustion engine is of particular interest as a direct improvement technique. One way to improve the efficiency of internal combustion engines is to reduce the friction of each sliding part. Engine oil is one of them. This article discusses fuel-efficient engine oils from two aspects:product standards and technology trends.

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  • Kazunori ISHIGAMI, Yoshie ARAKAWA, Makoto MAEDA
    2020 Volume 65 Issue 8 Pages 498-504
    Published: August 15, 2020
    Released: August 15, 2020
    JOURNALS RESTRICTED ACCESS

    Automatic transmissions have evolved in response to changes in the environment surrounding vehicles, and automatic transmission fluid have evolved as well. Currently, the automotive industry is facing a serious global warming problem and electrification is rapidly progressing to meet strict CO2 emission regulations. Furthermore, the era of “CASE”1) has arrived, and a period of major change has been reached. Looking back on the evolution of automatic transmission and changes in transmission fluid, this paper describes the performance required for transmission fluid in consideration of future market trends for transmission (Incl. reducer).

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  • Yohei SHONO, Fumiyuki NARA
    2020 Volume 65 Issue 8 Pages 505-510
    Published: August 15, 2020
    Released: August 15, 2020
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    As with automotive lubricants, the trend in refrigeration oils for refrigerators is toward lower viscosities, in pursuit of higher energy efficiency. A viscosity grade (VG) of 32 was once common for refrigeration oils. Recently, however, an extremely low viscosity refrigeration oil (VG3) for refrigerators is needed. Extremely low viscosity oils such as VG3 cause problems in flash points and anti-wear properties, resulting high friction coefficient in low speed region. However, it was found that the problem could be overcome by improving the base oil blending and additive formulation, and VG3 oil can contribute to the high efficiency on refrigerators. It is expected that improvements of refrigeration oil for higher efficiency will continue in the future.

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  • Kazunori MIYAKE, Takeshi TSUDA
    2020 Volume 65 Issue 8 Pages 511-516
    Published: August 15, 2020
    Released: August 15, 2020
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    This article presents the grease lubrication technology which contributes to the torque reduction of the rolling bearing used for the motor. The effects of the stirring resistance which is generated when the ball and retainer push aside the grease are great in grease lubricated ball bearings. In addition to the yield stress, the viscous transfer stress and viscosity lowering energy are known to be the barometer of the fluidity of grease which affects the stirring resistance. It is reported that there is the correlation between the meniscus length and channeling properties of grease. Furthermore, the microscopic infrared spectroscopy revealed that types of grease affected the formation of the deposited film of the thickener. The method of the quantitation for the fluidity or formation of the lubricated film with using the atomic force microscope and confocal laser fluorescence microscope were reported, and the possibility of the torque reduction was expected with controlling these parameters.

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Original Contribution on Science
  • Takayuki TOKOROYAMA, Motoyuki MURASHIMA, Noritsugu UMEHARA
    2020 Volume 65 Issue 8 Pages 517-525
    Published: August 15, 2020
    Released: August 15, 2020
    [Advance publication] Released: June 09, 2020
    JOURNALS FREE ACCESS

    In general, Raman analysis is one of the useful candidates to obtain structure of carbonaceous coatings. To improve the depth resolution of Raman analysis, surface-enhanced Raman scattering (SERS) using gold nanoparticles (Au nanoparticles: AuNPs) and Au sputtered particles were investigated. The analysis was conducted to approximately 1.7, 2.4, 4.7, and 10.0 nm thickness of carbon coatings on silicon substrate with a 532 nm incident wavelength laser. The results indicated that the underlying silicon substrate was detected in the results of the Au sputtering method. Contrastingly, the underlying silicon substrate was not detected by the AuNPs method. This result clarified that using the AuNPs method, the detection depth of the carbon film was approximately 1.7 nm or less. The a-C:H coating was processed using a calotester, and SERS measurements at different depths were performed for the 633 and 532 nm wavelengths using the AuNPs method. As a result, the IG peak position tended to increase from the vicinity of the inter face between the a-C:H coating and the substrate to the surface. In addition, the ID/IG ratio was as low as 0.28 near the substrate and 0.72 at 3800 nm.

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