The effects of DLC-coated journal on improving seizure limit and reducing friction under engine oil lubrication

Ogihara, Hidemi; Iwata, Takumi; Mihara, Yuki; Kano, Makoto

doi:10.1177/14680874211012934

Cited by 3 publications

(4 citation statements)

References 6 publications

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“…The specifications of the bearings used are shown in Table 5. In a previous study [12,13], 17 mm wide bearings were used, but in the present study the bearing width was narrowed by 31% to 11.4 mm. That was done to make the difference in seizure properties clearer by increasing the contact pressure at the maximum load level of the bearing tester.…”

Section: Bearingsmentioning

confidence: 73%

“…The specifications of the bearings used are shown in Table 5. In a previous study [12,13], 17mm wide bearings were used, but in the present study the bearing width was…”

Section: Bearingsmentioning

confidence: 93%

“…The evaluations were performed using a bearing test rig as specified in ISO 21866-1 for automotive journal bearings [11], which makes it possible to examine the properties under fluid, mixed, and boundary lubrication regions. The friction and seizure properties of DLC-coated journals in a specific load range up to a maximum specific load of 121 MPa have previously been reported along with the related influence of surface roughness and engine oil additives [12,13]. In the present study, friction and seizure properties were investigated under specific load as high as 181 MPa, along with analyzing the sliding part surfaces and conducting acoustic emission (AE) tests to analyze the phenomena involved.…”

Section: Introductionmentioning

confidence: 93%

“…The highly rigid connecting rods apply the load to the journal in a step-like manner via the plain bearings by means of a hydraulic vibration generator (iv). It also has a tilting device (v) that adjusts the parallelism between the journal and the bearing [12,13]. The applied load is measured with a load cell (vi).…”

Section: Bearing Testermentioning

confidence: 99%

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Excellent Seizure and Friction Properties Achieved with a Combination of an a-C:H:Si DLC-Coated Journal and an Aluminum Alloy Plain Bearing

et al. 2021

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Friction occurring between the crank journal and main bearings accounts for a large share of the mechanical losses of automotive engines. The effects of higher in-cylinder pressures and narrower bearings have raised the specific load applied to bearings, making it essential to secure sufficient seizure resistance as well. For the purpose of meeting both requirements, we have endeavored to reduce friction and improve seizure resistance by applying a diamond-like carbon (DLC) coating to the crank journal. In the present study, a bearing tester was used that has received international standard certification from the International Organization for Standardization for reproducing the sliding behavior occurring between the crank journal and main bearings in actual engines. Test results indicated that a silicon-containing hydrogenated amorphous carbon (a-C:H:Si) DLC-coated journal showed a definite friction reduction and a marked improvement in seizure resistance. An acoustic emission (AE) analysis revealed that an adhesion-induced AE peak observed for a steel journal was not seen for the DLC-coated journal. Additionally, tin and aluminum elements in the bearing material that were transferred to and observed on the sliding surface of the steel journal were not seen on the DLC-coated journal. Accordingly, the low affinity of the DLC coating with these metal elements presumably led to the clear friction reduction and superior seizure resistance displayed by the DLC coating.

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Section: Bearingsmentioning

confidence: 73%

“…The specifications of the bearings used are shown in Table 5. In a previous study [12,13], 17mm wide bearings were used, but in the present study the bearing width was…”

Section: Bearingsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 93%

Section: Bearing Testermentioning

confidence: 99%

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Excellent Seizure and Friction Properties Achieved with a Combination of an a-C:H:Si DLC-Coated Journal and an Aluminum Alloy Plain Bearing

et al. 2021

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Comparison of mechanical and tribological properties of diamond-like carbon coatings doped with Europium and Gadolinium produced by HiPIMS

Fontes

Serra

Fernandes

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part B:

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Hydrogen-free diamond-like carbon (DLC) thin films can be employed for numerous applications, including engine components, once they exhibit good properties for that. They have been used as coatings due to their attractive properties, including high hardness, high wear resistance, and low CoF even under high load/pressure. One of the major limitations of hard hydrogen-free ta-C coatings applications is related to the low reactivity with oil additives used nowadays. The Ionic liquids (ILs) emerged as a novel class of lubricants that can be used in future lubricated systems due to possessing unique physical properties, like high thermal stability and conductivity. To improve the lubrication performance of DLC with ILs, the films were doped with rare earth metals such as Gd and Eu. These non-carbide-forming elements can be introduced in the DLC matrix, incorporated as single atoms, and improve the surface adsorption and reactivity of phosphorus-based IL, and consequently, the lubricating properties of DLC/ILs sliding contacts. However, many demanding applications require good performance across the different regimes (from boundary to hydrodynamic regime). Across all regimes, the boundary is the most challenging, where metal-to-metal contact occurs. Therefore, it is essential to study the influence of the doping elements on the doped-DLCs performance under the boundary regime. For comparison, a pure-DLC was used. In this study, Eu and Gd-DLC tribological systems are characterized by pin-on-disk test in dry conditions and by scratch test. Also, mechanical properties are studied through nano-indentation. Results show that samples doped with a low atomic concentration of Eu or Gd (1%–3%), despite having a CoF higher than un-doped DLC films, show typical values for pure-DLC coatings, like low specific wear rate (<10−16 m3/Nm) and high hardness (23 GPa), permitting, in the future, the combination of novel nanostructured alloyed-DLCs and ILs needed to achieve the optimal lubrication performance.

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ADAPTIVE DLC COATINGS WITH DIFFERENT MoS2 CONTENT

Osada,

Kot,

Zimowski

et al. 2024

Tribologia

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DLC coatings are widely used in engineering as they are resistant to abrasive wear. However, they exhibit anincreased coefficient of friction at temperatures of around 300C. Soft MoS2 coatings are known to maintaina low coefficient of friction at temperatures up to about 350C, but suffer from relatively high abrasive wear.Publications from the last decade report a synergistic improvement in the tribological performance of acoating consisting of both these materials. The aim of this study was to investigate the wear resistance ofcoatings composed of different a-C and MoS2 contents applied by magnetron sputtering on steel. The resultsobtained in tribological tests conducted using the ball-and-disk method showed at least 20% better adhesionto the substrate of the two-component nanocomposite coating and its increased wear resistance from 15% toas much as 700%, compared to single-component coatings in tests conducted at 20C and 250C. The testsshowed no deterioration of the two-component coating's coefficient value compared to DLC.

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The effects of DLC-coated journal on improving seizure limit and reducing friction under engine oil lubrication

Cited by 3 publications

References 6 publications

Excellent Seizure and Friction Properties Achieved with a Combination of an a-C:H:Si DLC-Coated Journal and an Aluminum Alloy Plain Bearing

Excellent Seizure and Friction Properties Achieved with a Combination of an a-C:H:Si DLC-Coated Journal and an Aluminum Alloy Plain Bearing

Comparison of mechanical and tribological properties of diamond-like carbon coatings doped with Europium and Gadolinium produced by HiPIMS

ADAPTIVE DLC COATINGS WITH DIFFERENT MoS2 CONTENT

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