Clarification of a Semi-Empirical Approach in Piston Ring/Cylinder Bore Conformability Prediction

Dunaevsky, V.; Rudzītis, Jānis

doi:10.1115/ijtc2006-12318

Cited by 5 publications

(4 citation statements)

References 9 publications

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“…Many authors have studied the influence of bore distortions on ring conformability but, most of the time, those on the ring have been disregarded. [28][29][30][31] Few works dedicated to this issue addressed the problem from a tribological point of view. [22][23][24][25] Figure 1 shows that the ring defects should also be taken into account since they can induce an aperture of several hundredths of millimeters.…”

Section: Dimensionless Form and Scale Analysismentioning

confidence: 99%

“…If β < 1, (i.e. in the case of a good conformity between the bore and the ring, see equation (20d)), the flow remains in the creeping regime as can be inferred from equations (31). Using the boundary conditions given in equations ( 25) to (28), the integration of the flow equations can be performed yielding the following solution…”

Section: Flow Regimes Identificationmentioning

confidence: 99%

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Gas flow through a bore-piston ring contact

Hallouin

Lasseux

Senger

2020

International Journal of Engine Research

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This work reports on the derivation of simplified but accurate models to describe gas flow through a bore-piston ring contact in reciprocating machines like compressors or IC engines. On the basis of the aperture field of a contact deduced from real measurements carried out on an expanding ring in a bore, a scale analysis on the complete compressible flow model is performed, assuming ideal gas law. It is shown that the flow can be treated as stationary and three distinct flow regimes can be identified (namely incompressible, compressible creeping, and compressible inertial regimes). Three dimensionless parameters characterizing these regimes are identified. While for the two former regimes, classical analytical Poiseuille type of models are derived, an Oseen approximation is further employed for the latter, yielding a quasi-analytical solution. The models are successfully compared to direct numerical simulations (DNS) of the complete initial set of balance equations in their steady form performed on an aperture field of sinusoidal shape. These simplified models are of particular practical interest since they allow an accurate gas flow-rate estimate through a real contact using the aperture field as the geometrical input datum, together with the thermodynamic conditions (pressure and temperature). This represents an enormous advantage as DNS is still very challenging in practice due to the extremely small value of the contact aperture to contact length ratio.

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Section: Dimensionless Form and Scale Analysismentioning

confidence: 99%

Section: Flow Regimes Identificationmentioning

confidence: 99%

Gas flow through a bore-piston ring contact

Hallouin

Lasseux

Senger

2020

International Journal of Engine Research

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“…By describing a distorted bore profile in this form, Müeller [9] further developed a set of bounds for each Fourier order of distortion, and Luenne and Ziemb [10] adopted these bounds in the development of a measurement system for evaluating the distortion characteristics of cylinder liner. Similarly, Dunaevsky [11,12] explored a random process based scheme to present the tightness of contact on PRCI. In this scheme, a design criterion was proposed to quantify amplitude and order of bore distortions regarding the piston ring conformability.…”

Section: Introductionmentioning

confidence: 99%

Distortion Optimization of Engine Cylinder Liner Using Spectrum Characterization and Parametric Analysis

Yang

2016

Mathematical Problems in Engineering

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In an automotive powertrain system, the cylinder liner is one of the most critical components which possesses the intricate structural configurations coupled with complex pattern of various operational loads. This paper attempts to develop a concrete and practical procedure for the optimization of cylinder liner distortion for achieving future requirements regarding exhaust emissions, fuel economy, and oil consumptions. First, numerical calculation based on finite element method (FEM) and computational fluid dynamics (CFD) is performed to capture the mechanism of cylinder liner distortion under actual engine operation conditions. Then, a spectrum analysis approach is developed to describe the distribution characteristic of operational loads (thermal and mechanical) around the circumference of a distorted cylinder bore profile; the FFT procedure provides an efficient way to implement this calculation. With this approach, a relationship between the dominant order of distortion and special operational load is obtained; the design features which are critically relative to cylinder liner distortion are also identified through spectrum analysis. After characterizing the variation tendency of each dominant order of distortion through parametric analysis, a new design scheme is established to implement the distortion optimization. Simulation results indicate that a much better solution is obtained by using the proposed scheme.

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“…Bardzimashvili et al (2004) examined various existing conformability criteria with a ring-pack model and concluded that the higher orders of deformations may need to be considered as well as the effect of gas pressure. A summary of the existing empirical and/or analytical methods is given in Dunaevsky and Rudzitis (2007). Ma et al (1997) implemented the ring bore gap calculation into their tribological model.…”

Section: Introductionmentioning

confidence: 99%