scholarly journals Surface Texture Influences on the Running-in Behavior and Friction Reduction

2018 ◽  
Vol 159 ◽  
pp. 02017
Author(s):  
Zhouyong Hou ◽  
Tomomi Honda

For improving automobile fuel efficiency, the internal combustion engines must be required to reduce the friction and wear. Changing viscosity of lubricant and surface pressure could succeed, but the seizure is easy to happen in engines. However, the surface texture can solve those problems. The running-in behavior affects friction and wear on whole combustion engines. If the running-in is not carefully designed, catastrophic accident can happen. This experiment investigates that the running-in behavior is influenced by textured surfaces and the tested materials are the cast iron and the different area ratio of dimple of aluminum alloy combination. The friction coefficient and the number and size of wear particles are measured by the friction sensor and particle counter. After the tests, the worn surfaces are measured through using surface profile measurement systems, and some significant phenomena are observed and analyzed. The textured surface verifies good consequence and tribological advantages.

2015 ◽  
Vol 1119 ◽  
pp. 142-150
Author(s):  
Yusuke Morita ◽  
Marleen de Weser ◽  
Gerhard Schottner

To improve the fuel efficiency of automobile internal combustion engines, we investigated the fundamental mechanism of friction reduction within engine moving parts. A new coating was designed by introducing SiO2nanoparticles in FEP film. The SiO2nanoparticles were functionalized with hydrophobic fluoroalkyl units on their surface to create additional low friction property. Universal Surface Tester friction measurements revealed a significant reduction of the friction coefficient with increasing number of hydrophobic fluoroalkyl units for SiO2surface functionalization. To clarify the friction reduction mechanisms by the functionalization of SiO2nanoparticles, a quantum chemical calculation was carried out. The result indicates that an attractive force occurs between nanoparticle Si atoms and polymer F atoms, while by adding fluoroalkyl units on the SiO2nanoparticle surface, this force changes to repulsive. By performing a molecular dynamics simulation of a shear model between FEP film and SiO2nanoparticles, we observed a decrease of friction force with increasing fluoroalkyl units which lead smooth rolling motion of nanoparticles, thus confirming the repulsive effect of nanoparticle functionalization. We conclude that fluoroalkyl units on the SiO2surface play an important role in creating a repulsive force between nanoparticle and FEP film which lead to low friction coefficient.


Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2761 ◽  
Author(s):  
Cheng Liu ◽  
Yanjun Lu ◽  
Yongfang Zhang ◽  
Lujia Tang ◽  
Cheng Guo ◽  
...  

In internal combustion engines (ICEs), the frictional performance of ring-liner conjunction (RLC) has drawn special attention because it greatly affects the fuel efficiency of the engines. In recent years, surface texture (i.e., micro dimples or grooves) has emerged as a promising approach to improve the frictional performance of RLC. However, most current studies on surface textured RLC were conducted by assuming that the liner was ideally circular and the lubrication condition was either fully flooded or starved. In this study, to evaluate the frictional characteristics of an RLC with surface texture on the ring, a numerical model of lubrication is presented by considering the liner deformation, as well as the coexistence of the fully flooded and staved lubrication conditions in an engine cycle. On this basis, the frictional properties of a surface textured RLC are analyzed, and the impacts of the liner deformation and temperature on the friction-reducing effect of the surface texture are also evaluated. The results show that the surface texture on the ring can effectively reduce the power dissipation and friction dissipation of an RLC, and the reductions vary with the liner temperature and deformation. Large reductions in the power dissipation and friction dissipation of an RLC are obtained when the liner temperature is low or the liner deformation is small.


2021 ◽  
pp. 146808742110129
Author(s):  
Hidemi Ogihara ◽  
Takumi Iwata ◽  
Yuji Mihara ◽  
Makoto Kano

Internal combustion engines have been improved markedly in recent years through efforts to conserve resources, reduce emissions and improve fuel efficiency. In this regard, the authors have been working to reduce friction and improve the seizure properties of the crankshaft main journal and main bearing. These mechanical components of internal combustion engines incur large friction losses. In order to reduce friction, journals have been coated with a diamond-like carbon (DLC) coating, which has been reported to reduce friction in the fluid lubrication regime in recent years. Another current issue of journals and bearings is the need to improve seizure resistance. Therefore, these properties were evaluated for material combinations of aluminium alloy bearings and DLC-coated journals, which have low affinity. The results revealed that friction was reduced under a fluid lubrication regime and seizure resistance was improved under a mixed lubrication regime.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jinlong Shen ◽  
Tong Zhang ◽  
Jimin Xu ◽  
Xiaojun LIU ◽  
Kun Liu

Purpose This paper aims to improve the tribological performance of grease-lubricated spherical plain bearings (SPBs) under heavy load, dimple-type textures were prepared by laser on the outer surface of the inner ring. The influence of roughness parameters of a textured surface on reducing friction coefficient and temperature rise was also explored. Design/methodology/approach This study adopts a laser processing method to fabricate dimple-type textures. Three-dimensional roughness parameters were used to characterize the textured surfaces. The friction coefficients of five SPBs with surface texture and one original commercially available SPB without surface texture under different nominal loads were measured on a self-established test rig. The data of temperature rise were obtained by nine embedded thermal couples. Findings The results indicate that SPBs with textures generally exhibit lower friction coefficients than the original SPB without textures. The dimple depth has a significant influence on improving the tribological performance, which coincides with the analysis by surface roughness parameters. A textured surface with negative Ssk and high Vvc has the minimum temperature rise. Originality/value As it is too difficult to arrange sensors into heavy-load SPBs, there are few reports about the temperature characteristics. Through nine embedded thermal couples, the distribution of temperature rise on the inner ring of SPBs was given in this study. The positive effect of surface texture on reducing temperature rise and friction coefficient was verified, which is beneficial for the design of heavy-load SPBs.


Author(s):  
Xin Tong ◽  
Shucai Yang ◽  
Xianli Liu ◽  
Weiwei Liu ◽  
Chunsheng He

In the research regarding laser-processed micro-textured carbide tool surfaces, there remains a lack of research on the relationship between micro-textured preparation processes and the degree of fatigue wear experienced by micro-textured surfaces. To study the effect of a laser-textured surface on the friction and wear properties of friction pairs, it first of all conducted friction and wear tests to obtain optimal processing parameters. By using a scanning electron microscope, the fatigue wear mechanism for a micro-textured surface was observed. Experimental results based on fatigue wear theory show that a micro-textured surface phase has better fatigue resistance than a smooth surface. Under the same friction conditions and selected test parameters, a micro-textured surface phase can reduce the maximum fatigue and friction wear of a smooth surface by 38.4%. This study provides a theoretical basis and source of reference for the rational formulation of micro-texture parameters and improvements in the performance of micro-textures during cutting processes.


Author(s):  
Andrew Ahn ◽  
Thomas S. Welles ◽  
Benjamin Akih-Kumgeh

Abstract Byproducts of fossil fuel combustion contribute to negative changes in the global climate. Specifically, emissions from automobiles are a major source of greenhouse gas pollution. Efforts to minimize these harmful emissions have led to the development and sustained improvement of hybrid drivetrains in automobiles. Despite many advancements, however, hybrid systems still face substantial challenges which bear on their practicality, performance, and competitive disadvantage in view of the low cost of today’s traditional internal combustion engines. These imperfections notwithstanding, hybrid electric vehicles have the potential to play significant roles in the future as cleaner transportation solutions. Actualization of this potential will depend on the ability of hybrid-electric vehicles to minimize their disadvantages while increasing their positive features relative to traditional combustion engines. This research investigates current hybrid electric architectures in automobiles with the aim of suggesting an alternative, more efficient hybrid configuration that utilizes current technology. This is completed by utilizing an iterative design process to compare how various components of existing hybrids can be combined and/or improved to develop a single, efficient and cohesive system that performs comparably to or surpasses existing ones in fuel efficiency and low emissions in all driving conditions. A critical and comparative analysis is provided based on current hybrid-electric vehicle architectures as well as a plausible alternative.


Author(s):  
S. Sivrikova ◽  
J. Rojdestvensky ◽  
I. Petrov ◽  
S. Popova

Quality, reliability and fuel efficiency of internal combustion engines (ICE) substantially depend upon optimum choice of lubrication system and tribocontact design and a lubricant liquid. This paper describes a quasistatic method of analysis of ICE lubrication systems for Newtonian and non-Newtonian oils. The method allows for both transient and steady-state conditions.


2020 ◽  
Vol 10 (11) ◽  
pp. 3705
Author(s):  
Ahmad Alshwawra ◽  
Florian Pohlmann-Tasche ◽  
Frederik Stelljes ◽  
Friedrich Dinkelacker

Reducing friction is an important aspect to increase the efficiency of internal combustion engines (ICE). The majority of frictional losses in engines are related to both the piston skirt and piston ring–cylinder liner (PRCL) arrangement. We studied the enhancement of the conformation of the PRCL arrangement based on the assumption that a suitable conical liner in its cold state may deform into a liner with nearly straight parallel walls in the fired state due to the impact of mechanical and thermal stresses. Combining the initially conical shape with a noncircular cross section will bring the liner even closer to the perfect cylindrical shape in the fired state. Hence, a significant friction reduction can be expected. For the investigation, the numerical method was first developed to simulate the liner deformation with advanced finite element methods. This was validated with given experimental data of the deformation for a gasoline engine in its fired state. In the next step, initially conically and/or elliptically shaped liners were investigated for their deformation between the cold and fired state. It was found that, for liners being both conical and elliptical in their cold state, a significant increase of straightness, parallelism, and roundness was reached in the fired state. The combined elliptical-conical liner led to a reduced straightness error by more than 50% compared to the cylindrical liner. The parallelism error was reduced by 60% to 70% and the roundness error was reduced between 70% and 80% at different liner positions. These numerical results show interesting potential for the friction reduction in the piston-liner arrangement within internal combustion engines.


2018 ◽  
Vol 12 (4) ◽  
pp. 603-610 ◽  
Author(s):  
Yue Sun ◽  
Keita Shimada ◽  
Shaolin Xu ◽  
Masayoshi Mizutani ◽  
Tsunemoto Kuriyagawa ◽  
...  

Experimental investigations were carried out to verify if the friction reduction in lubrication can be expanded by a textured surface with sawtooth riblets. Sawtooth riblets were formed by ultraprecision diamond cutting, with a ridge angle of about 60°–90° and height of about 20–50 μm on the contact surface. Six types of textured surfaces with different ridge angles, heights, and sliding directions were tested and compared with the untextured surface. The tribological tests were conducted by a flat-on-flat tribometer in lubrication. The effects of the ridge angle, height, and relative sliding direction on the friction coefficient in lubrication were reported.


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