Connecting Rod Bearings Research Articles

Solving a thermohydrodynamic lubrication problem for complex-loaded sliding bearings with allowance for rheological behavior of lubricating fluid

A method for calculating thermohydrodynamic characteristics of complex-loaded sliding bearings is considered. The non-Newtonian behavior of a fluid, as well as processes of heat transfer between a lubricating film and surrounding moving surfaces of the tribojoint, are allowed for. Results of calculating hydromechanical characteristics of a connecting-rod bearing of an internal combustion engine are presented.

Partitioned fluid-structure methods applied to the solution of elastohydrodynamic conformal contacts

The functional characteristics of statically-loaded journal bearings operating in the elastohydrodynamic lubrication (EHL) regime are evaluated by means of three partitioned fluid-structure coupling methods. Widely used in other areas but yet unexplored in the context of EHL problems related to journal bearings, these methods permit the use of optimized codes to solve the hydrodynamic and structural equations separately employing different techniques specialized in each type of equation. In this study, lubricant pressures are calculated using the isothermal Reynolds equation and the p−θ mass-conserving formulation is adopted for the computation of cavitation effects. An appropriate substructuring technique is applied in order to reduce the order of the bearing 3D linear-elastic finite element model. The efficiency and robustness of the partitioned fluid-structure coupling methods presented are assessed for two extreme situations of high deformation and high load conditions of a typical internal combustion engine connecting-rod big-end bearing. Numerical results evidence that partitioned fluid-structure coupling methods consist in a very efficient simulation tool for EHL journal bearing analyses.

An analytical approach towards EHD analysis of connecting-rod bearing

Elastohydrodynamic (EHD) journal bearings in rotating machine parts are subjected to very severe operat-ing conditions, leading to a reduction in the minimal thick-ness of the lubricating film which can generate premature wear of the contact. In this work, an analytical method of calculating the minimal thickness of the oil film was pro-posed. It takes into account the effect of the elastic defor-mations due to both hydrodynamic pressure and inertia. The elastic deformations are calculated analytically and simultaneously. The connecting – rod bearing body defor-mations was predicted under low and moderate engine regimes. The correction produced by the introduction of the effect of inertia, have shown a clear difference for the global behaviour. The method was applied for analysis of a General Motors connecting – rod bearing engine. DOI: http://dx.doi.org/10.5755/j01.mech.20.2.6935

Facile wear failure monitoring of commercial bearing alloys using I-kaz method

Numerous methods have been well developed in the area of bearing monitoring. This paper presents an experimental study of wear monitoring of connecting rod bearings type AA7075-T6 within audio frequency signals; f<20kHz against a AISI4340 hardened steel via air-borne with the aid of tribometer. The objective of this study is to determine the correlation between the noise signals and wear responses via air-borne method generated due to the sliding wear action. The wear tests were carried out by using a pin-on-disc configuration at a range of sliding speed 5.24, 7.85 and 9.95m/s. A set of sliding distance was utilised, ranging from 20 to 160km at a fixed load of 200N. The test was performed under a lubricated sliding condition using a SAE40 type lubricant to imitate the actual operation of the connecting rod bearings. Presented results were obtained using a microphone 40SC type which was located 10mm from the pin-on-disc contact. The extracted noise was represented as numerical descriptor of I-kaz coefficient, Z̵∞ using MATLAB software. From the analysis, it was noted that the specific wear rate K′, value was proportional to an increase of sliding velocity in which K′ lies in between 1.36 and 7.96×10−8mm3/Nm. Based on the morphology investigation, it was found that under a lubricated test, parallel grooves and craters up to 10μm in size were present, indicating the occurrence of the abrasive action of fresh abrasive action caused by the entrapment of hard debris particles that protruded soft mating materials thus, resulting a higher coefficient of friction. Oxides formation in adhesive junction was attributed to yield a lower friction, and this was clearly supported by X-ray diffraction spectra on worn surfaces. Furthermore, from the microstructure observation of worn surfaces it was also strongly suggested that a combination of adhesion, abrasion, fatigue and delamination wear mechanisms had occurred. Detailed changes in wear responses were analysed and displayed in I-kaz™ 3D spaces. This approach is capable of determining bearing condition, thus allowing the end-user to monitor the wear rate and the degradation of the bearings.

Effect of changes in operating power of gasmotocompressors 10 GKN on the diagnostic signs of connecting rod bearings defects

Effect of changes in operating power of gasmotocompressors 10 GKN on the diagnostic signs of connecting rod bearings defects

The Analysis of the Deformation and Contact Lubrication Problem of HPD Diesel Engine Connecting Rod Bearings Based on the FFT Method and Flexibility Matrix Method

Based on the fast fourier transform (FFT) and flexibility matrix method, the effects of the FFT and flexibility matrix method on the distribution of oil film pressure, elastic deformation in the steady load and the journal center orbit of the connecting rod big-end bearings in the dynamic load are investigated. The results are shown that when the eccentricity ratio is more than 1, the maximum oil film pressure obtained by FFT method is bigger on both ends of the journal bearing and on its intermediate position is smaller. To the connecting rod big-end bearing, under the dynamic load condition, there is the same trend of the journal center orbit with two methods. However, with FFT method, the journal is largely deviated from bearing center.

Experimental Study on Anti-Fatigue Damage Structural Design of Diesel Engine Bearings

With higher requirements on energy-saving and environmental protection of diesel engine in the modern times, the loads on main bearing and connecting rod bearing of diesel engine are continuously increased, and also working conditions are even more critical. Bearings are the key moving parts of diesel engine, and play an important influence on reliability, service life and other performances of diesel engine. Therefore, the reasons for fatigue damages to its bearings greatly affect fatigue life. In traditional designs, effects of the problem are studied few. In this paper, therefore, this problem is studied for discussing the formation reasons and solutions for it theoretically.

Wear Monitoring of Connecting Rod Bearing via Air-Borne Method Analyzed by Using I-Kaz&lt;sup&gt;TM&lt;/sup&gt; Multi Level Value

Different techniques have been developed in the area of bearing wear monitoring. This paper proposes a different experimental study on bearing wear monitoring by using an airborne technique. The data captured in the airborne technique will be analyzed by using I-kazTM Multi Level (7Z) coefficient and then will be correlated with the conventional specific wear rates, K. The wear tests were carried out by using a pin-on-disc configuration at a sliding speed of 7.85 m/s. A set of sliding distance ranging from 20 160 km at a fixed load of 200 N was utilized and the K value was measured at every interval of 20 km for the speed. SAE40 type lubricant was used in the test to simulate the actual operation of the connecting rod bearing. The audio range frequency below 20 kHz in the airborne technique was obtained through a microphone 40SC type which was placed 10 mm from the pin-disc contact. The analysis result showed that the wear rate, K increased from 1.82 to 6.70x10-8 mm3/Nm as the sliding distance increased, indicating that a mild-abrasion wear regime had occurred. The curve fitting of K as a function of I-kazTM Multi Level coefficient showed a similarity to an established of Taylor Tool Life curve. Thus, it was possible to correlate the Taylor curve and worn bearing, mainly in monitoring and identifying the bearing condition with respect to the sliding distance. The trend of I-kazTM Multi Level coefficient was found to be consistent with the increase of sliding distance which indicates that the I-kazTM Multi Level value can positively be used as wear response indicator for bearing.

Wear Monitoring of Connecting Rod Bearing via Air-Borne Method Analyzed by Using I-Kaz&lt;sup&gt;TM&lt;/sup&gt; Multi Level Value

Different techniques have been developed in the area of bearing wear monitoring. This paper proposes a different experimental study on bearing wear monitoring by using an airborne technique. The data captured in the airborne technique will be analyzed by using I-kazTM Multi Level (7Z) coefficient and then will be correlated with the conventional specific wear rates, K. The wear tests were carried out by using a pin-on-disc configuration at a sliding speed of 7.85 m/s. A set of sliding distance ranging from 20 160 km at a fixed load of 200 N was utilized and the K value was measured at every interval of 20 km for the speed. SAE40 type lubricant was used in the test to simulate the actual operation of the connecting rod bearing. The audio range frequency below 20 kHz in the airborne technique was obtained through a microphone 40SC type which was placed 10 mm from the pin-disc contact. The analysis result showed that the wear rate, K increased from 1.82 to 6.70x10-8 mm3/Nm as the sliding distance increased, indicating that a mild-abrasion wear regime had occurred. The curve fitting of K as a function of I-kazTM Multi Level coefficient showed a similarity to an established of Taylor Tool Life curve. Thus, it was possible to correlate the Taylor curve and worn bearing, mainly in monitoring and identifying the bearing condition with respect to the sliding distance. The trend of I-kazTM Multi Level coefficient was found to be consistent with the increase of sliding distance which indicates that the I-kazTM Multi Level value can positively be used as wear response indicator for bearing.

Design predictive tool and optimization of journal bearing using neural network model and multi-objective genetic algorithm

In this paper, rapid and globally convergent predictive tool for dynamically loaded journal bearing design is developed. For accomplishment of such an aim, a neural network model of crankshaft and connecting rod bearings in an internal combustion engine is developed as an alternative for the complicated and time-consuming models. Six most important parameters are selected as inputs of neural network. These parameters are: oil viscosity, engine speed, bearing radial clearance, bearing diameter, slenderness ratio and maximum force applied on bearings. Also, some significant parameters are calculated as neural network outputs. These parameters include: all components of friction loss, all components of oil consumption, minimum oil film thickness, eccentricity, oil temperature rise and displacement relative to shell. In addition, an optimum analysis is performed. To achieve such a target, multi-objective optimization methodology is a good approach inasmuch as several types of objective are minimized or maximized simultaneously. The optimization goal is to minimize friction loss and lubricant flow as the two objectives and develop a Pareto optimal front.

Fatigue Analysis of Diesel Engine Connecting Rod Based on Finite Element Method

Connecting rod fatigue in a certain type of diesel engine is analyzed by using finite element analysis method and the FEM software ANSYS. According the actual working conditions, the three-dimensional model with multi-body contact is established to simulate the contact between the connecting rod parts; By using APDL language programming, the work load on the connecting rod, calculated according all the link work loads, is applied to the connecting rod bearing and bushing through the oil film pressure distribution. By finite element method structural strength of the connecting rod was calculated, that can effectively guide the connecting rod design, which has been proved by practice.

Visual Computation of Thermohydrodynamic Lubrication of Dynamically Loaded Journal Bearings

The Reynolds equation and energy equation with the thermal balance equation in combination were applied to build the thermohydrodynamic (THD) computational model of the dynamically loaded journal bearings. The most popular development platform——Visual C ++ in the field of computer science and the drawing platform of AutoCAD were combined with the medium of ObjectARX and the object oriented programming technology was used, on the basis of which, the visual computational software of the THD lubrication of the dynamically loaded journal bearings for main shaft and connecting rod bearings of automobile engines was developed. The analysis results of an example indicate that the bearing behaviors are closely tied to the radial clearances and inlet lubricant temperature of the bearing.

Experimental Investigation of the Effect of Biodiesel Utilization on Lubricating Oil Degradation and Wear of a Transportation CIDI Engine

In the present experimental research work, rice-bran oil methyl ester (ROME) is derived through transesterification of rice-bran oil using methanol in the presence of sodium hydroxide catalyst. On the basis of previous research for performance, emission, and combustion characteristics, a 20% (v/v) blend of ROME (B20) was selected as optimum biodiesel blend. This experimental investigation was aimed to investigate the effect of biodiesel on wear of in-cylinder engine components. Endurance tests were conducted on a medium duty direct injection transportation diesel engine with B20. Tests were conducted under predetermined loading cycles in two phases: engine operating on mineral diesel (B00) and engine fueled with B20. After completion of these tests, engines were dismantled for observing the physical condition of various vital engine parts, e.g., piston rings, bearings, cylinder liner, and cylinder head. Physical measurements of these vital parts were also carried out to assess the wear of these parts. The physical wear of various parts except big end bearings (connecting rod bearing bore) were found to be lower in the case of B20 fueled engine. Wear metals in the lubricating oil samples drawn from the engines at regular intervals were investigated. Relatively lower wear concentrations of all wear metals except lead were found in the lubricating oil of B20 fueled engine. To quantify the wear of cylinder liners, surface parameters at different locations in the liner (top dead center, bottom dead center, and midstroke) were measured and compared. A qualitative analysis was also carried out by conducting surface profiles and scanning electron microscopy at the same locations.

Hydromechanical characteristics of complex-loaded siding bearing with allowance for nonroundness of the pivot shaft and bush

The problem of calculating the hydromechanical characteristics of complex-loaded sliding bearings is formulated in which the cross section of the bearings is shaped to limit the lubricating layer and the shape is different from the ideal (round cylindrical) one. The results of calculation of the hydromechanical characteristics of the crankshaft connecting-rod bearing of a diesel engine are analyzed where the pivot journal and bush are oval.

Couple Stress Effects on the Dynamic Behavior of Connecting Rod Bearings in Both Gasoline and Diesel Engines

An isothermal hydrodynamic analysis of big end connecting rod bearings for both diesel and gasoline engines lubricated with couple stress fluids is undertaken. Based on the V. K. Stokes micro-continuum theory, an incompressible modified Reynolds equation is derived from the fluid motion and mass conservation equations using the assumptions of thin-film theory. The hydrodynamic performance and the crank pin center trajectories are determined numerically by means of the Booker mobility technique. Compared with the Newtonian lubricant case, the lubricants with couple stresses provide an increase of the minimum film thickness, and a drastic decrease of the power loss, peak pressure, and flow rate over one engine cycle for both engines.

Throttle seals for crankshaft bearings

At high operating temperatures, differences in the coefficients of thermal expansion for light metal engine blocks and steel crankshafts cause large bearing gaps to open up between the crankshaft and the main bearing shells. In such cases, significant amounts of oil are needed to ensure an adequate supply of oil to the crankshaft main bearing and the connecting rod bearing. There is also the additional risk of insufficient lubrication at low speeds, e.g. at hot idle. Adapting the oil pump to suit these operating conditions does not get to the root of the problem. Throttle seals by Freudenberg that are integrated into the bearing shells offer a completely new approach.

Simulation and test-supported design procedure for highly stressed engine sliding bearings

New technical developments such as downsizing in conjunction with an increase in peak pressure and engine speed are leading to higher loads on the crankshaft bearings and connecting rod bearings in internal combustion engines. As a result, there is a greater proportion of mixed friction conditions, which limits the durability of the bearings due to increased wear. A crucial key to a better understanding of the tribological conditions in the engine sliding bearing and their relevance for wear and failure criteria lies in the development of simulation techniques that allow the parameters that determine mixed friction conditions to be considered. By application of these simulation techniques, substantial cost savings in expensive test stand tests can be achieved before testing in the engine takes place by pre-selection of the bearing geometry and combinations of materials. The following presents a concept for sliding bearing design on the basis of a connecting rod bearing that was developed at the Institute for Mechanical Components and Construction Technology of the University of Kassel. It combines the advantages of simulation and experiment in a single procedure.

Engine Lubrication System Analysis by Considering Aeration and Cavitation within the Rotating Oil Supply Passage

The connecting rod big-end bearing is one of the most heavily loaded components of the lubrication circuit system of modern combustion engines. The bearing's oil supply has to be designed accordingly in order to ensure its sustainable operating reliability. As can be seen, the oil supply has to pass the main bearing and the rotating crankshaft before entering the connecting rod bearing. It is common knowledge that the centrifugal forces due to the crankshaft rotation affect the oil flow through the rotating supply passage into the rod bearing. The oil pump has to maintain a certain pressure level in the main oil gallery to overcome these centrifugal forces. In the early eighties, the second oil pressure limitation to the rod bearing operation was identified, which is lower than the centrifugal pressure limit. As a result of this, the dissolved air will be released in the rotating oil passage due to the pressure decrease caused by the centrifugal forces. Aeration or cavitation within the rotating oil supply passage occurs at much lower oil pressure. The detrimental effects of aeration or cavitation are loss of lubrication, overheating, metal erosion, mechanical shocking, and even system component failures. In this paper, a novel approach of identifying the second pressure limit is introduced by applying the CFD method. The three-dimensional, transient, multiphase flow in the transfer passage has been solved by considering its dynamic attributes. The characteristics of the aeration and cavitation flows and their effects on rod bearing oil supply have been investigated. The mechanisms underlying the interrupted oil supply to the rod bearing have been discussed in detail by studying the dynamics of aeration and cavitation. Finally, a map of the operational range has been established as an exemplary guideline for the design of engine lubrication systems and the key operating conditions including rotational speed and main bearing inlet pressure. Review led by Yuan-Ren Jeng

Development of an Experimental Device to Study Real Connecting-Rod Bearings Functioning in Severe Conditions

The paper presents a new experimental device made to analyze the thermoelastohydrodynamic (TEHD) behavior of connecting-rod bearings functioning in severe conditions. First, it focuses on the test bench description. The general principle of the test bench and then the main original technological solutions used with respect to the functional specifications are detailed. Two numerical models are described. They were developed in order to design and to validate two central components of the experimental device. Finally, the paper comments on the test results used to understand and validate the traction∕compression loading system, which is one of the key points in the test bench behavior.

Analysis of non-Newtonian and piezoviscous effects in dynamically loaded connecting-rod bearings

The dynamic behaviour of three elastic connecting-rod big-end bearings is studied. Non-Newtonian and piezoviscous behaviour of the lubricant is included. The present algorithm allows accurate analysis of film rupture and reformation during actual operation of an engine and is based on finite element discretization. The non-Newtonian effect is introduced by modifying the viscosity for each point of a three-dimensional mesh of the film and for each iteration. Using a convenient iterative solution procedure, converged solutions for lubricant flow and elastic deformation fields are obtained. The present algorithm is extended to a global thermo-elastohydrodynamic model, to take into account the effects of viscosity variation with temperature. It is shown that the non-Newtonian shear-thinning and oil piezoviscous effects cannot be neglected in a complete connecting-rod bearing analysis. Furthermore, thermo-elastic behaviour can lead to different conclusions, than obtained by the elastohydrodynamic model.