Deformation Of Crankshaft Research Articles

Cylinder pressure reconstruction to compensate for crankshaft flexibility based on flexible crank model

Amid escalating economic demands and emissions regulations for internal combustion engines, an array of control strategies grounded in in-cylinder state feedback has been introduced and implemented. The exploration of cylinder state feedback has captured the attention of researchers, and one area of intense focus involves reconstructing cylinder pressure based on engine state information due to its cost-effectiveness. In this paper, we introduce a method for compensating crankshaft flexibility. This method encompasses a crankshaft dynamic model, a 17-dimensional input vector, the PCA (Principal Component Analysis) algorithm, and a signal-layer perceptron. This approach efficiently addresses the impact of flexible crankshaft deformation and ensures high accuracy. The results demonstrate that all R2 values for cylinder pressure signals reconstructed via the proposed method exceed 0.9997, with RMSE predominantly ranging between 0.4 and 0.6 bar. Furthermore, the error in Pmax calculation based on cylinder pressure signals is under 0.04 bar, LPP (Location of Peak Pressure) error is below 2°CA, CA50 error remains under 0.5°CA, and IMEPH error is within 0.3 bar. In summation, the presented method facilitates highly precise in-cylinder pressure reconstruction, satisfies the prerequisites for in-cylinder combustion state feedback.

Research on the thermohydrodynamic lubrication performance of engine main bearing with rough surface considering the axial motion and deformation of crankshaft

In this paper, the influence of the thermal effect on the lubrication performance of engine main bearing with rough surface considering the axial motion of crankshaft is investigated. In the analysis, the crankshaft-bearing system of a four-cylinder four-stroke engine is taken as the object. The axial motion of crankshaft is measured by the engine bench test. The journal load of main bearing and crankshaft deformation are calculated by the whole crankshaft finite-element method. The analysis model is established based on the average flow lubrication model. The lubrication of main bearing is analyzed by the dynamic method. The temperatures of lubricating oil and bearing are calculated by the energy equation and solid heat conduction equation. The results show that the influence degree of the axial motion of crankshaft on the lubrication of engine main bearing with rough surface is greatly affected by the thermal effect. When the thermal effect is considered, the influence of the axial motion of crankshaft on the lubrication of engine main bearing makes its working condition deteriorate further. When the axial motion of crankshaft is considered, the influence of the thermal effect on the lubrication of different main bearings varies significantly.

DYNAMIC STRUCTURAL ANALYSIS OF ENGINE CRANKSHAFT AT DIFFERENT ANGLE OF CRANK TURNS FOR THREE DIFFERENT MATERIALS

For many years, engines have been one of the main power machinery of different kinds of applications, and the main part of power machinery is a crankshaft that converts the piston’s reciprocating displacement with four-link mechanisms into rotary motion. . The major limitation of the engine crankshaft is fatigue failure due to repeated load caused by bending and torsional load. In this paper, the comparative dynamics structural analysis was carried out for three different materials such as forged steel, cast iron, and chromium-molybdenum steel with different angles of turns of cranks from 0° to 720° and to predict the stresses, deformation, and fatigue life of crankshaft without compromising its weight, strength and reliability. The 3D CAD model was simulated with FEA software. The simulated results show that by applying bending load and torsional load for three materials, the maximum stresses produced in the fillet area of the main bearing journal and in the fillet area of the crankpin journal at a crank angle of 360° respectively. The deformation results revealed that maximum deformation occurs at the mid-surface of the crankpin. From fatigue life prediction it was observed that forged steel and chromium-molybdenum steel shows better fatigue life as compared to cast iron. Moreover, in the comparative study, it was concluded that chromium-molybdenum steel shows fewer stresses and better fatigue life. Therefore it is suggested that chromium-molybdenum steel would be the better option for manufacturing crankshaft.

Mixed elastohydrodynamic analysis of a coupled journal-thrust bearing system in a rotary compressor under high ambient pressure

The hermetic rotary compressor's bearings, including the thrust bearing, the main and sub bearings, work together under high ambient pressure. The thrust bearing works under light axial loads, but sever wear is found, which may be related to the crankshaft's misalignment and deformation and the high ambient pressure. To investigate this phenomenon, a complete coupled journal-thrust bearing model is constructed. The bearing forces are calculated with the mixed elastohydrodynamic model under high boundary pressure. The effects of the deformations and ambient pressure on the bearing performance are investigated. Results show that ignoring the crankshaft deformation makes the simulation underestimate the thrust bearing wear, and the high ambient pressure is the leading cause of the thrust bearing wear.

Fault feature and diagnostic method of bending micro- deformation of crankshaft of piston engine

ABSTRACT The crankshaft is the core component of a piston engine. Once a bending deformation fault occurs in the crankshaft, it can cause serious damage to the safe operation of the entire engine. However, diagnostic methods for detecting this fault are rare. In this paper, the influence of a bending micro-deformation of the crankshaft (BMDC) on the gear transmission system (GTS) was studied through theoretical analysis and simulation calculation. A fault diagnosis method for the BMDC based on the axial force of the crankshaft and the radial displacement of the flywheel gear (RDFG) was proposed. A three-dimensional model of the GTS of a diesel engine was established. The impact of the BMDC on the gear train and the fluctuation of the RDFG were calculated through a multi-body dynamics simulation. Finally, a condition monitoring and fault diagnosis system (CMFDS) was built to monitor the engine, and the effectiveness of the proposed method was verified by fault instances.

Ймовірнісна модель показників деформування колінчастих валів унаслідок відновлення їхніх шийок наплавленням

Для відновлення ресурсу колінчастих валів автомобільних двигунів широко застосовують різні способи наплавлення їхніх шийок. Встановлено, що найкращі результати за твердістю наплавленого матеріалу в разі відновлення колінчастих валів, без застосування термічного оброблення, отримують під час наплавлення пружинним дротом під флюсом АН 348А за легування металу вуглецем та хромом через флюс. Виявлено, що під час наплавлення деталі під флюсом відбувається значне нагрівання наплавлених ділянок, яке поширюється також на ділянки, що не піддаються наплавленню. Цьому сприяють лінійні та об'ємні розширення нагрітих ділянок деталі, осадження затвердлого розплавленого металу та перебіг структурних змін і перетворень у ньому. Як з'ясувалося, це супроводжується появою у наплавленому та основному металі розтягувальних або стискувальних напружень, під дією яких змінюється початкова геометрична форма деталі, тобто вона деформується. Встановлено, що деформування деталі може виникнути також і від згину, перекосу або її скручування у затискному пристрої, від надмірного стиснення у центрах верстату або від теплового видовження у процесі наплавлення тощо. У випадку невеликих величин деформування правлення колінчастих валів після наплавлення не обов'язкове, оскільки їхня співвісність за корінними шийками може бути досягнута в процесі механічного оброблення. Для цього необхідно спочатку шліфувати всі шатунні шийки й в останню чергу – корінні. За величин деформувань, більших від допустимих, деталі піддають правленню або утилізуванню. Для оцінки впливу на величину деформування колінчастих валів двигунів ЗМЗ 511.10 після їхнього відновлення наплавленням і подальшого шліфування побудовано ймовірнісну модель. На основі статистичного опрацювання результатів досліджень встановлено закономірності зміни випадкової величини (деформувань) за допомогою побудови емпіричного розподілу і кривої теоретичного розподілу, які підпорядковуються нормальному закону (Крива Гауса). Перевірка узгодження теоретичного та емпіричного розподілів за критерієм Пірсона показала задовільний збіг.

Numerical study on lubrication performance of engine main bearing with rough surface considering axial movement of crankshaft

In actual operation of an engine, the crankshaft will move along the axis direction of engine main bearings under the combined influence of various influencing factors. Considering the axial movement and crankshaft deformation, a new lubrication model of engine main bearings with rough surface was built based on the average Reynolds equation. The influence of axial movement of deformed crankshaft on performance of main bearing with rough surface was studied. In this study, the axial movement law of deformed crankshaft is measured through experiment, and the finite element method was applied to solve the tilting of crankshaft in the bearing bore resulted from the crankshaft deformation. The results show that the axial movement of deformed crankshaft has a significant impact on performance of main bearing with rough surface. No matter whether or not the surface roughness is considered, the journal center trajectories of main bearings are unclosed three-dimensional space curve due to the axial movement of deformed crankshaft. The influence level of the axial movement of deformed crankshaft on lubrication characteristics of main bearings is directly related to the surface roughness. The influence trend and level of the surface roughness on lubrication characteristics of main bearings are obviously changed when considering the axial movement of crankshaft.

Modal Analysis of L Type Compressor Crankshaft

Reciprocating compressor is an important equipment in industrial production. The crankshaft turns the thrust of the compressor piston rod into torque, which is an important component of the compressor. When reciprocating compressor works, there will be various forms of vibration such as torsion and bending. Therefore, the study of the crankshaft vibration becomes particularly important. Analyze the modal analysis of L type compressor crankshaft by using the finite element simulation. The first six order natural frequency and the corresponding mode of vibration of the crankshaft are obtained. And analyze the influence of the hollow and solid on the natural frequency and mode of vibration of the crankshaft. The results show: With the increase of vibration order, the natural frequency of the crankshaft increase. The crankshaft deformation is mainly bending at low frequency. The deformation of crankshaft is mainly composed of bending and torsional vibration at higher frequency. Moreover, the ends of solid crankshafts are less restrained. Extend the service life and performance of the crankshaft and other parts of the compressor by increasing the strength and stiffness of the crankshaft's local materials. And increasing the fillet radius at the transition point are adopted to reduce the deformation and torsion of the crankshaft.

Influence of die-forging deformation on microstructure of 1538MV non-quenched and tempered steel for crankshaft

Non-quenched and tempered steels offer many advantages such as energy saving, emission reduction, simple processing, short production time, and low cost. Demand for energy saving and emission reduction is increasing with the rapid increase of car production and ownership. As a result, the usage of non-quenched and tempered steel in automotive parts has attracted increasing attention. The main problem with non-quenched and tempered steel in actual production is the lack of a hot deformation process and a cooling process that can be used to precisely control the microstructure and properties of the material. The material 1538MV is a type of pearlite+ferrite non-quenched and tempered steel, and its use for building crankshafts has not been studied sufficiently thus far. The main factors affecting the structure of a crankshaft are deformation, final forging temperature, and metal flow and cooling after forging. In this paper, the forging process of 1538MV non-quenched and tempered steel for building a crankshaft was studied by means of numerical simulation, microstructures of the rolled material and finished crankshaft were analyzed, and influence of deformation on the microstructure of the crankshaft was discussed. The results show that the microstructure of a crankshaft forged at a higher temperature and with smaller deformation is coarser than that of a crankshaft made of rolled material. The inhomogeneity of the microstructure is caused by unevenness of temperature and strain distribution during crankshaft deformation. The ferrite content of the crankshaft and the pitch of the pearlite were lower than those of the rolled material, and the bainite structure appeared in a few parts, which indicated that the cooling rate was too fast during phase transformation. Therefore, the cooling process should be optimized further. In addition, the metal flow in the segregation zone during the crankshaft forging process significantly influences the forged microstructure of the crankshaft, which is another cause of the formation of bainite. Therefore, the quality of the rolled material should be strictly controlled. The above results provide directions for improving the quality of the rolled material, optimization of the crankshaft forging process, and optimization of the cooling process after forging.

Nowa koncepcja przyrządu do pomiaru odkształceń ramion wykorbień wałów korbowych metodą symetryczną

The patent pending design of the crank shaft deformation measuring device by means of the symmetric method, was presented. The new solution eliminates imperfections and inaccuracies resulting from the method currently used for this purpose, and enables correct assessment of the crankshaft positioning in main bearings.

ИССЛЕДОВАНИЕ ПРЕДЕЛЬНОГО СОСТОЯНИЯ КОЛЕНЧАТОГО ВАЛА СУДОВОГО СРЕДНЕОБОРОТНОГО ДИЗЕЛЯ

The limiting state of the marine medium speed diesel engine crankshaft occurs as a result of the influence of three basic factors: kinematics error, plain bearings wear, and fatigue of material. A kinematics error causes deformation of the crankshaft, uneven wear of bearings and material fatigue. The crankshaft deformation is monitored by radial runout of the crank journal and change of distance between crankwebs. The legitimate values of deformation are defined by the manufacturer and tested in practice. According to the data taken from the literature, there has been analyzed the process of the crankshaft bearings wearing. The main reason is found an abrasive wear of plain bearings. The uneven wear of crankshaft necks results in their ovality and conicity. Non-cylindrical shape of the neck is the principal reason of plain bearings faults. The phenomenon of the crankshaft fatigue has been studied. Exceeding warning limits of crack length and area on the neck surface, which is mentioned in diesel technical service and repair manual, will result in changing crankshafts with cracked necks. The different types of diesel crankshaft fatigue destruction have been educed. The problem of crack development inside a crankshaft has been studied. The estimations of limiting depth of neck craking are offered based on the results of emergency fatigue fracture of crankshaft, taking into account recommendations of firms-manufacturers and experience of repair. The estimations of crankshaft neck cracking average speed have been given on the basis of study of emergency situations. An example of successful renewal of crankshaft with deep cracks has been demonstrated. After magnetic particle or dye penetrant testing it has been recommended to use the crack depth gauge RMG 4015. Crack control experience has been investigated in the course of the process of 8NVD48A2-U diesel crankshaft neck surface cracking by a decreasing of diesel load.

Coupled differential algebraic equations in the simulation of flexible multibody systems with hydrodynamic force elements

AbstractThe mathematical modelling of elastohydrodynamic bearings in combustion engines leads to a coupled system of (partial) differential algebraic equations, which is represented by a flexible multibody system model of the engine including crankshaft and bearing and by the Reynolds equation that describes the non‐linear effects in the fluid film. The hydrodynamic forces depend strongly on the position and the elastic deformation of crankshaft and bearing shell. We discuss the influence of the spatial discretization on accuracy and numerical effort. Since a fine spatial discretization substantially slows down the numerical solution, we propose a semi‐analytical method based on singular perturbation theory to speed‐up time integration. Numerical tests for a simplified benchmark problem illustrate the advantages of this approach. (© 2014 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Experimental Research on a Three-Dimensional Journal Orbit of a Crankshaft Bearing for an Internal Combustion Engine

The current experimental researches on the orbit of a journal center of a crankshaft bearing for an internal combustion engine were usually focused on the 2D movement locus of a crankshaft journal center in the cross section of the bearing. However, in the actual operation of an internal combustion engine, there exists the movement of a crankshaft journal along the bearing axis under the effect of various factors, such as the crankshaft deformation acted by load. Obviously the tribological performance of a crankshaft bearing is affected inevitably by the movement of the crankshaft journal along the bearing axis. In this paper, a four-stroke four-cylinder internal combustion engine was taken as the studying object, the 3D orbit (that includes the movement in the cross section of the bearing and the movement along the bearing axis) of the journal center of the crankshaft bearing for an internal combustion engine was measured under a number of operating conditions on the test bench of an internal combustion engine. The position of the journal in the crankshaft bearing was obtained by the measurement using eddy current gap sensors and the data post-process. The results show that there exists the movement of the crankshaft journal along the axial direction in the bearing for an internal combustion engine. The actual orbit of the journal center of the crankshaft bearing for an internal combustion engine is a 3D spatial curve. The orbit of the journal center of the crankshaft bearing in one operating cycle of an internal combustion engine is not a closed curve. There is relatively a large movement of the journal along the axial direction of the crankshaft bearing, and the numerical value of the movement is greater than the radial clearance of the bearing. The greater the rotational speed of the internal combustion engine, the larger the amount of axial movement of the journal. The periodic variation exists in the axial movement of the bearing journal in one operating cycle of the internal combustion engine at low engine speed, and the varying periodicity equals the number of engine cylinders. There is no obvious varying rule of the axial movement of the bearing journal in one operating cycle of the internal combustion engine at high engine speed.

Analysis and Detection of Elastic Deformation of the Large-Scale Crankshaft in Non-Circular Grinding

Due to the discontinuous axis and the big ratio of length to diameter, the large-scale crankshaft is easy to generate the complex elastic deformation under the effect of the huge gravity and the clamping force on non-circular grinding machine. The distinctive deformation deteriorates the coaxiality of all the main journals and thus the grinding precision of crankpins in non-circular grinding. In this paper, the statics analysis of large-scale crankshaft has been conducted by using the finite element simulation. The overall deformation of crankshaft and the position offset of each main journal center without or with the auxiliary supports have been simulated and contrasted. The results manifest that the auxiliary support forces produced by the steady rests have the positive effect on the compensation for crankshaft deformation. On this basis, to satisfy the demand of position adjustment of the upper and lower support pads of servo-controlled open steady rest, the on-machine measurement method and device of the position of main journal center is proposed. And then the offset calculation model of the main journal center is deduced using the measured data. The measurement method and device are beneficial for the straightening of the crankshaft and the improvement of machining accuracy of crankpins in non-circular grinding.

On the elastohydrodynamic lubrication performance of crankshaft bearing based on the effect of whole engine block deformation

PurposeThe elastic deformation of crankshaft bearing surface will be caused when acted by oil film pressure, which will affect the lubrication performance of crankshaft bearing. The model of the single bearing housing was usually used in the calculation of the elastic deformation of bearing surface. In actual internal combustion engine, the main bearing housing is combined together with engine block; deformation of the main bearing surface will be affected by deformation of the engine block. The purpose of this paper is to investigate the effect of deformation of the whole engine block on the hydrodynamic lubrication performance of main bearings.Design/methodology/approachThe loads of main bearings were calculated by the whole crankshaft beam‐element finite element method. The lubrication of crankshaft bearings was analyzed by dynamic method. The elastic deformations of bearing surface under oil film pressure were calculated by compliance matrix method. The compliance matrix was established by finite element analysis.FindingsIt may be not necessary to consider the effect of elastic deformation of bearing surface under film pressure in the lubrication analyses of main bearings for internal combustion engine when the very high calculating accuracy is not required.Originality/valueThe elastohydrodynamic lubrications of crankshaft bearings considering the deformation of engine block were analyzed for the main bearings of an engine. Till now, whether or not the complicated model of the whole cylinder block should be considered to calculate the elastic deformation of main bearing surface in the lubrication analyses of crankshaft main bearings has not been done.

Dynamic Balancing Modal Analysis and Vibration Suppressing Design for Reciprocating Compressor Crankshaft

The purpose of this study is to improve the problem of vibration which occurs in a running reciprocating compressor, by determining an optimal crankshaft counterweight and narrowing the movement trajectory of the crankshaft connecting rod mechanism. An analytical solution method is applied to satisfy the requirements for vibration reduction. Use of finite element software is to simulate the modality and deformation of crankshaft under various conditions of counterweight. Modal testing shows a difference of less than 6 % between the simulation and the experimental results. After the crankshaft counterweight is machined and installed, the new crankshaft is able to reduce compressor vibrations from 32 mm/s down to 15.8 mm/s and noise reduction of 3 dB. This study can provide information pertaining to the design process and assessment to any future new compressor designs.

Research on the Effect of Whole Cylinder Block on EHL Performance of Main Bearings Considering Crankshaft Deformation for Internal Combustion Engine

In this paper, the analyses of elastohydrodynamic lubrication (EHL) of crankshaft bearings considering the deformation of the whole cylinder block and crankshaft under load were carried out for the crankshaft bearing system of a four-stroke four-cylinder internal combustion engine. The lubrication of crankshaft bearing was analyzed by dynamic method. The deformation of bearing surface under pressure of oil film was calculated by compliance matrix method. The results show that when the crankshaft deformation under load is considered, compared with the results of not considering the deformation of cylinder block, the maximum film pressure decreases, the minimum film thickness increases, and the end leakage flow-rate and frictional coefficient of journal surface change little in an engine working cycle when considering the deformation of cylinder block. The models of the whole cylinder block and the single main bearing housing were used, respectively, to calculate the deformation of main bearing surface in the analyses. The results show that the calculation accuracy of the elastohydrodynamic lubrication analyses of crankshaft main bearings can be met basically by applying the simple model based on the single main bearing housing to calculate the elastic deformation of main bearing surface.

Whole crankshaft beam-element finite-element method for calculating crankshaft deformation and bearing load of an engine

Crankshaft deformation and bearing load are very important for the lubrication ana-lyses of crankshaft bearings of an engine. The calculating methods of crankshaft deformation and bearing load will affect the results. There were some problems in the current methods used for calculating crankshaft deformation and bearing load, such as complicated model, more time taken for calculation, and error brought by simplification. In this article, the crankshaft of a four-cylinder engine was taken as the object of study, and the whole crankshaft beam-element finite-element method to calculate crankshaft bearing load and crankshaft deformation of a multi-cylinder engine was studied. The results show that this method is closer to the actual condition and can calculate the loads of all main bearings simultaneously compared with traditional methods used for calculating the crankshaft bearing load of a multi-cylinder engine. Meanwhile, this method is a simple, convenient, time-saving method used for calculating crankshaft deformation compared to the whole crankshaft solid-element finite-element method, and its calculating precision can meet engineering demands.

Elastohydrodynamic Lubrication Analysis of Crankshaft Bearing Considering Crankshaft Deformation under Load and Roughness Surface

The elastohydrodynamic lubrication properties of crankshaft bearings considering crankshaft deformation under load and surface roughness for a four-cylinder internal combustion engine are studied.The lubrication of crankshaft bearing is analyzed by kinetics method.The deformation of bush surface under pressure of oil film is calculated by deformation matrix method.The results show that surface roughness has great effect on crankshaft bearing orbit,the surface deformation of bearing affects crankshaft bearing orbit little.When surface roughness of bearing is considered,the highest film pressure of crankshaft bearing increases obviously,the least film thickness decreases remarkably,and the end flow-rate changes little in most time.When elastic deformation of bearing surface is considered,the highest film pressure of bearing decreases to different extent;the influence of elastic deformation of bearing surface on the end flow-rate,journal frictional coefficient and the least film thickness is very small.

Research on elastohydrodynamic lubrication of a crankshaft bearing with a rough surface considering crankshaft deformation

Journal misalignment in bearings caused by crankshaft deformation under load exists generally in internal combustion engines. When serious journal misalignment takes place, the minimum oil-film thickness of bearings is greatly reduced and the maximum oil-film pressure of the bearings increases markedly. Therefore, it is necessary to consider the surface roughness and deformation of bearing surface when analysing the hydrodynamic lubrication characteristics of a misaligned bearing. In this paper, the elastohydrodynamic lubrication properties of crankshaft bearings considering crankshaft deformation under load and the surface roughness for a four-cylinder internal combustion engine were studied. The lubrications of the crankshaft bearings were analysed by the dynamic method. The deformation of the bush surface under the oil-film pressure was calculated by the deformation matrix method. The results show that, when crankshaft deformation is considered, the surface roughness has a marked effect on the orbits of the crankshaft bearings, but deformation of the bearing surface scarcely affects the orbits of the crankshaft bearings. When the surface roughness of a bearing is considered, the maximum oil-film pressure of crankshaft bearings obviously increases, the minimum oil-film thickness decreases markedly, and the end flowrate changes little in most of the engine cycle. When elastic deformation of the bearing surface is considered, the maximum oil-film pressure of bearings decreases to a different extent: elastic deformation of the bearing surface affects the end flowrate, the frictional coefficient of the journal, and the minimum oil-film thickness very little.