Thermal analysis of hydrodynamic lubricated journal bearings in internal combustion engines

Abstract

Hydrodynamic journal bearings are essential components in the internal combustion engines. The prediction of their reliability, durability, and economy, and also of their friction loss power and wear, are of highest importance. For an appropriate representation of the hydrodynamic load-carrying capacity and also the friction behavior, the multibody dynamics of the contacting components, the shape of the contacting component surfaces, the amount of the available lubricant, and the properties of the lubricant itself are of importance. A Reynolds-averaged equation with laminar flow conditions in combination with a dry asperity contact model and a multibody dynamic simulation of the structural components is a typical modeling approach for that purpose. Furthermore, this paper shows a newly developed model for the temperature distribution in the lubricant and the bearing structures. It includes thermal interface conditions between these domains, which incorporates the asperity energy source and predicts the temperature in supply areas. The presented method is applied for a typical engineering task of a sensitivity analysis for oils with different viscosity index improvers in a main bearing of a four-cylinder inline diesel engine. The influence of the oil film temperature on the oil film viscosity and, therefore, on the load-carrying capacity is shown. Furthermore, the simplified two-dimensional approach is compared with a three-dimensional approach in terms of the obtained result. The presented results show similar accuracy of the two-dimensional approach compared to the equivalent three-dimensional case.

Elastohydrodynamic analysis of a journal bearing with different grade oils considering thermal and cavitation effects using CFD-FSI

“…The distribution of oil film temperature determined by the current study was compared to that determined by Ferron et al (1983) [16], as depicted in figure (4). This graph demonstrates the strong correlation between the two distributions of oil film temperature, with a maximum variance of 1.26 percent.…”

Modelling and Co-simulation of hybrid vehicles: A thermal management perspective

“…This work involves modelling the friction in both the engine [92,108] and transmission incorporating things such as bearing friction models [109], pistons liner contact [110], valvetrain lubrication, friction in the gear mesh [111], torque converter efficiency and torque losses due to pumping requirements. These models tend to use similar methodology to the coolant circuit with the added complexity that the relevant properties of the oil, such as viscosity, are much more variable with temperature [112].…”

Sub-Synchronous Vibrations of a Rotor Supported on Poorly Lubricated Journal Bearings

“…Motions of the rotor are decomposed to elastic and gross coordinates. In order to simulate both types of the motion, the system of 2 differential algebraic equations described by Lorenz et al (2017) is employed (time is omitted):…”

“…We assume that the oil is an incompressible Newtonian fluid, the film is thin, the flow in the film is laminar and cavitation may occur. Pressure * is then governed by the Reynolds equation in the form (Lorenz et al, 2017…”