Piston Ring Lubrication and Cylinder Bore Wear Analyses, Part II—Theory Verification

Abstract

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.

Fractal Prediction Model During the Wear Process Based on Archard Formula

“…It is considered that only adhesive wear theory established by Bowden and Archard formula are scientific laws in these well-known wear calculation models. There are a lot of researches and applications based on the Archard formula, Zhang Jiasi deduced the simplified formula of material's wear rate with the condition of the middle and low temperature based on the concept of wear mechanisms [7]; Zhang Yishan established a mathematical model to characterize cylinder liner and piston ring during running-in process by using liner 's surface roughness and wear rate as two state parameters of the system [8]; Ting and Mayer proposed a wear analysis model which can calculate the wear on piston ring's thrust surface based on Archard theory [9].Archard model is widely used in the wear calculation, the model assumes that all the bonding points are the hemispherical asperities, it corrected the assumption by introducing adhesion wear constant [3], however, there aren't accurate calculation method for the adhesion wear constant, and the constant is determined by experiment which can range from 10 …”

Modeling of Abrasive Wear in a Piston Ring and Engine Cylinder Bore System©

“…Further, K is constant as well since it depends on the hardness of the bore and the abrasive particle as defined in Eq. [4]. K abrasion is a constant for the given piston ring/bore system during the steady-state period, which can be determined experimentally using a pin-on-disc test.…”

Mathematical Model of Piston Ring Sealing in Combustion Engine

“…number of stages and a way of their connection by means of throttling gaps depend on a odeled engine and a degree of model advancement. In the simplest models in which gas is assumed to flow only through ring locks, labyrinth has a series structure and number of throttling channels is equal to that of sealing rings [2, 4,27,17,18,9,16]. There are also models of this kind in which sealing action of piston oil rings is taken into account [15,25,1,22].…”

“…Furuhama and Tada [3] calibrated empirically the so determined mass flux by means of a flow coefficient of constant value. This manner of the modeling of gas flow through ring lock was used in the models [27,18,9,16, 1] where however various values of the coefficient were assumed. In the model [26] a flow coefficient of value depending on the ratio of pressure before and behind the orifice, was used.…”

“…In the majority of models [2, 4,27,17,18,13,31,20,1,22] it was assumed that cross-sections of gas flow through ring lock and spaces of labyrinth stages are constant. In actual engine, volumes of inter-ring and behind-ring spaces , and especially cross-sections of gaps in locks , may change within a broad range during one cycle of engine work due to displacing motion of the piston together with rings along cylinder liner of a variable diameter.…”