scholarly journals Discussion: “Piston Ring Lubrication and Cylinder Bore Wear Analysis, Part I—Theory” (Ting, L. L., and Mayer, Jr., J. E., 1974, ASME J. Lubr. Technol., 96, pp. 305–313)

1974 ◽  
Vol 96 (3) ◽  
pp. 313-314
Author(s):  
J. L. Cherubim
Author(s):  
Yibin Guo ◽  
Wanyou Li ◽  
Dequan Zou ◽  
Xiqun Lu ◽  
Tao He

In this paper a mixed lubrication model considering lubricant supply conditions on cylinder bore has been developed for the piston ring lubrication. The numerical procedures of both fully flooded and starved lubrication were included in the model. The lubrication equations and boundary conditions at the end of strokes were discussed in detail. The effects of piston ring design parameters, such as ring face profile and ring tension, on oil film thickness, friction force and power loss under fully flooded and starved lubrication conditions due to available lubricant supply on cylinder bore were studied. The simulation results show that the oil available in the inlet region of the oil film is important to the piston ring friction power loss. With different ring face crown heights and tensions, the changes of oil film thickness and friction force were apparent under fully flooded lubrication, but almost no changes were found under starved lubrication except at the end of a stroke. In addition, the oil film thickness and friction force were affected evidently by the ring face profile offsets under both fully flooded and starved lubrication conditions, and the offset towards the combustion chamber made a large contribution to forming thicker oil film during the expansion stroke. So under different lubricant supply conditions on the cylinder bore, the ring profile and tension need to be adjusted to reduce the friction and power loss. Moreover, the effects of lubricant viscosity, surface composite roughness, and engine operating speed on friction force and power loss were also discussed.


1974 ◽  
Vol 96 (2) ◽  
pp. 258-266 ◽  
Author(s):  
L. L. Ting ◽  
J. E. Mayer

Based on the analytical method presented in the previous paper (Part I), comparisons of predicted wear curves along the major and minor side-thrust sides of the cylinder bore are made with the measured ones obtained from several truck engines for various vehicle mileages. The agreement was found to be good. This indicates the analytical model developed in Part I is relevant and suitable for predicting the severity of piston-ring bore contact for varying engine operating and lubrication conditions. From this, the necessary parameter changes may be found such that the wear rate of the cylinder bore may be reduced. Wear factor data, however, must be available in order to make quantitative predictions of wear. The model ultimately may be useful also in the design optimization of engine components. Since the method is general, it also can be applied to other reciprocating piston devices, such as gas compressor, Rankine cycle engine, or Stirling engine.


1974 ◽  
Vol 96 (3) ◽  
pp. 305-313 ◽  
Author(s):  
L. L. Ting ◽  
J. E. Mayer

An analytical method developed for determining the bore wear pattern for a reciprocating piston engine over a complete running cycle is presented. The method includes the considerations of the hydrodynamic lubrication theory between the ring and the cylinder bore wall, piston ring geometric and elastic characteristics, blowby through the piston ring pack, minimum film thickness permitting film lubrication, piston side thrust load and Archard’s wear relation. Since the method is general, it also can be applied to other reciprocating piston devices, such as gas compressor, Rankine cycle engine or Stirling engine. Wear factor data, however, must be available in order to make quantitative predictions of wear. The verification of the present theory is given in a subsequent paper (Part II) which shows good agreement between the predicted bore wear curves and measured ones for actual engines.


1994 ◽  
Vol 116 (3) ◽  
pp. 470-478 ◽  
Author(s):  
Yuanzhong Hu ◽  
Herbert S. Cheng ◽  
Takayuki Arai ◽  
Yoichi Kobayashi ◽  
Shunichi Aoyama

The assumption of axisymmetry, employed by most of studies on piston ring lubrication, probably gives a too idealistic model for the real situation. A theoretical model for a nonaxisymmetrical analysis of piston ring lubrication has been established in the present study. When a piston ring with an arbitrary free shape is fitted into the cylinder bore, the determination of ring deflection and contact load has been modeled mathematically as a Linear Complementary Problem (LCP). By combining LCP solution with lubrication analysis, the film thickness and contact load distribution over the circumference are obtained, leading to a more realistic simulation for piston ring lubrication. The friction force between piston ring and cylinder bore is predicted by the mixed lubrication model including the effects of surface roughness and asperity contact. The static distortion of cylinder bore, gas pressure variation, and lubricant starvation are also considered in the simulation. Results show that the contact pattern and film thickness between piston ring and cylinder bore are not exactly axisymmetrical. The main reason for the nonuniform contact is the asymmetry of ring elasticity, the static distortion and dynamic load created by the secondary movement of piston skirt.


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