The present work describes a lumped parameter approach for the filling analysis of engine lubrication systems. Filling analyses are typically carried out by means of multi-phase 3-D CFD models but, despite allowing detailed and reliable results, they require very demanding computational capabilities. Based on these premises, the authors present a modelling procedure to address the topic by means of a lumped parameter approach. By introducing a detailed modelling technique, the proposed method offers the possibility to reproduce not only the common and simple elements such as pipes and bends, but also permits the discretization of complex three-dimensional fluid domains. The proposed approach has been applied to the lubrication system of a heavy-duty V6 engine: since long stop intervals are planned during the engine lifetime, the filling time of the system plays a fundamental role. The analysis has been run with the obtained 0-D model, simulating at different lubricant temperature. The predictive capabilities of the numerical model are presented in terms of flow pattern and filling time of the circuit branches. The simulation has also been performed by means of a 3-D CFD model, providing the possibility of a result comparison: since this methodology is nowadays considered the state of the art for this kind of analyses, the results are taken as reference to evaluate the capabilities of the proposed 0-D approach. The comparative analysis concerns both the overall distribution of the lubricant over time, and the local phenomena. The differences in terms of computational effort are considered as well, to assess the approximation of the lumped parameter approach with respect to the complex but more accurate three-dimensional models. The results highlight the accuracy of the methodology on the estimation of the filling time. Moreover, the proposed procedure reveals great advantages in terms of computational effort.

本工作描述了一种用于发动机润滑系统填充分析的集总参数方法。填充分析通常是通过多相3-D CFD模型进行的，但是，尽管允许详细而可靠的结果，但它们却需要非常苛刻的计算能力。基于这些前提，作者提出了一种集总参数方法来解决该主题的建模过程。通过引入详细的建模技术，所提出的方法不仅提供了再现常见元素和简单元素（如管道和折弯件）的可能性，而且还使复杂的三维流体域离散化成为可能。提议的方法已应用于重型V6发动机的润滑系统：由于在发动机使用寿命期间计划了较长的停机间隔，系统的填充时间起着根本性的作用。已使用获得的0-D模型进行了分析，并在不同的润滑剂温度下进行了模拟。数值模型的预测能力以流型和回路分支的填充时间表示。还通过3-D CFD模型进行了仿真，从而提供了进行结果比较的可能性：由于当今已将此方法视为此类分析的最新技术，因此可将结果作为评估方法的参考。建议的0-D方法的功能。比较分析既涉及润滑剂随时间的总体分布，也涉及局部现象。在计算工作量方面的差异也要考虑在内，相对于复杂但更精确的三维模型，评估集总参数方法的近似值。结果突出了该方法在填充时间估计上的准确性。此外，所提出的程序在计算工作量方面显示出很大的优势。