Papers by Keyword: Piston Ring

Abstract: This paper mainly studies the position of the contact surface of the first ring groove of the piston under the condition of thermal mechanical coupling under the service conditions of the piston component of high-power diesel engine at the temperature of 350°C-420°C and the detonation pressure of the piston top of 28Mpa. For typical NDT defects such as surface crac0k, internal crack, shrinkage cavity and cold lap, the sensitivity of scale, morphology and position and their quantitative relationship. The crack defect on the upper joint surface of the piston ring causes the maximum stress in the range of 56.8 MPa-81.3 MPa. Among them, 8% of the circumference of a single defect will cause material damage and failure. Defects larger than this scale must be detected in eddy current NDT.

Abstract: This work presents and discusses the anitwear characteristics of surface modified CuO nanoparticle suspensions in bio-based lubricant. 1.0 wt% unmodified as well as surface modified CuO nanoparticles (nominal size of 50 nm), were dispersed in base oil using an ultrasonic probe. Wear protection was evaluated by using Four-Ball Extreme Pressure (EP) testing and sliding wear tests. The scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) analysis of the worn surface shows that: surface modification helped to improve the dispersion stability of CuO nanoparticles and related suspension show high EP characteristics in terms of load wear index and low cylinder liner wear due to surface mending effect of nanoparticles.

Abstract: In this research, we focus on the improvement of frictional performance of piston ring achieved by Laser Surface Texturing. Five kinds of samples (non-texture, dimple 100μm, dimple120μm, groove 45 degrees to sliding direction and groove 90 degrees to sliding direction) were tested under reciprocating sliding condition. The results showed that the sample of groove 90 degrees to sliding condition has the maximum decrease on either average friction coefficient (26%) or friction coefficient at end points of stock (33%). And we think that under boundary lubrication regime, the uniformity of distribution of the texture and flow of oil in contact surface are the key factors which affect the friction coefficient.

Abstract: The continuously tightening regulations limiting the amount of exhaust gas components of internal combustion engines force the manufacturers to further increase the effectivity of their power units. Due to the already relatively highly-developed state of engines result in the need of research and development of even smaller engine parts – e.g. piston rings. The main aim of this project was to develop a tool for the computer simulation of the behavior of the piston ring pack, which could aid the optimization process of the piston ring pack towards lowered friction losses.

Abstract: A Theoretical model was developed to study the potential use of surface texturing for reducing the friction between a piston ring and cylinder liner. The model can predict the load-carrying capacity and friction force of the piston compression ring from Reynolds equation. The investigation is carried out using different dimple depths as well as different dimple diameters. Micro-dimples on the piston ring were able to generate significant hydrodynamic support. Numerical results show that surface texturing can decrease the friction force and extend the load-carrying capacity. The optimum surface texturing parameters such as dimples depth and dimples diameter were found.

Abstract: This paper takes the SRV friction and wear tester, conducts the research on the abrasive principle of the tribomate pairs (Mo-alloy sprayed piston ring/P-B cylinder bore) under the condition that there lies a certain amount of quartz sand in the lubricant and find that the surface structure, chemical component of tribomate materials can have a huge influence on its capability of resisting abrasion.

Abstract: The COSRING-LUJET is a new concept for integrated solution to improve the lubrication regime in internal combustion engines. Introducing a conical shape for the peripheral surface of the rings, the authors analyze the conditions for the lubrication regime. Under this new concept, entitled COSRING, has developed a method for determining the transversal profile of the first and the second compression ring in order to obtain a better lubrication conditions for the piston ring – cylinder line assembly. On the other hand, the authors analyze the main factors affecting the cam-follower contact conditions, emphasizing the influence of the lubrication regime conditions over the couple wear reduction. The LUJET concept, proposed and studied by the authors, is an original solution for the improvement of the lubrication regime and engine life by using additional oil jets directed over the contact area.

Abstract: Compared with the conventional piston engines, the new rotary engine has many significant advantages, such as smaller volume and higher power density. Current studies at home and abroad are mainly focusing on aspects of its structural design, kinematics, dynamics analysis, except mechanical efficiency. In conventional piston engines, frictional loss of the piston group accounted for 65% of the total friction power loss ^[1]. In order to provide the scientific basis for designing low friction piston of the rotary engine, this paper combine the average two-dimensional Reynolds equation, the asperity contacts equation, viscosity-temperature equation and loads balance equation, proposing a method for calculating the friction power loss, and the applying the method to calculate the friction power loss of piston group of a new rotary engine.

Abstract: This paper modeling the piston ring of a new double-rotor engine based on the analysis, use Matlab program some code and woke out the numerical solution of the model,analyze the change of the gas leakage in the condition of different gas-room volume, different opening area, different spindle rotational speed, which provide strong evidence for improving sealing of the new double-rotor engine and ameliorating sealing design.

Abstract: The paper takes the SRV friction and wear tester, conducts the research on the abrasive ability of the three tribomate pairs (ceramic piston ring and P-B, Cu-Cr-Ni-Mo and bainite cylinder bores) under the condition that there lies a certain amount of quartz sand in the lubricant and find that the more hardness of cylinder bores, the more capability of resisting abrasion. The capability of resisting abrasion of ceramic piston ring/bainite cylinder bores is the best in three tribomate pairs.