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This paper presents a new configuration to tackle a twofold problem affecting a crankshaft: the torsional vibrations and the oscillation of the speed at the back end of the shaft due to the torque ripples created by the cylinders. These two phenomena already have industrial solutions, but the requirement levels increase and impose constant improvements. Moreover, the common vibration dampers rely on energy dissipation as heat, which in a context of waste reduction could be avoided. This concept relies on the association of an optimal passive mechanical damper, an electric circuit and electromechanical converters, without any external power supply, in order to ensure a safe operation. From a more fundamental point of view, these elements link a time-periodic correction and a nonstationary cyclic excitation. The core idea of the concept is to enable a redistribution of the energy within this coupled electromechanical circuit, where each element can behave as a power consumer or supplier, so that the oscillations of the mechanical elements can be decreased. In this paper, the authors describe and model this new concept in order to investigate the resulting dynamic behavior and the key design parameters that affect the damping performance. [ABSTRACT FROM AUTHOR]

—he influence of the mechanical properties of a thin metal–ceramic film on the wear rate of the frictional surfaces in the shaft–coating–bush system is investigated. By adjusting the chemical composition of the shaft, coating, and bearing bush, the mechanical and tribological properties may be modified, and hence the system's performance may be improved. [ABSTRACT FROM AUTHOR]

Internal combustion engines are thermal engines in which a fuel-air mixture undergoes combustion within the combustion chamber. The high-pressure and hightemperature gases generated during this process expand, exerting force upon the pistons and converting chemical energy into mechanical energy. This retraction movement is transformed into a rotational motion that generates the necessary torque to rotate the wheels via the crankshaft. Common examples of these engines include four-stroke and two-stroke piston engines, gas turbines, jet engines, and most rocket engines. This study aims to develop a model of the piston-connecting rodcrankshaft system and investigate the thermal and mechanical stresses resulting from its operation. Utilizing the finite element method in conjunction with ANSYS software, the simulation of thermal and mechanical stresses is carried out, while random vibrations are applied to represent potential imperfections and errors during operation. The SOLIDWORKS program is employed for the design and illustration of the system. Simulation results indicate that maximum vertical stress and shear stress are primarily distributed along the piston heads and connecting rods. [ABSTRACT FROM AUTHOR]

This study describes the remanufacturing process scheme and key technologies of waste compressors. Firstly, the technical characteristics of compressors for home appliances such as refrigerators and air conditioners are summarised. Then, the remanufacturing process scheme is proposed with the waste refrigerator compressor as the research object. The purpose or requirements of key processes such as separation, disassembling, cleaning, detecting, remanufacturing and reassembling are also elaborated. Moreover, the corresponding remanufacturing technology or method is proposed to satisfy the structural, quality requirement, economy and environmental friendliness of products and components. The cleaning technology of the compressor motor stator and the remanufacturing technology of crankshaft is highlighted. In accordance with the structural and quality requirement of the motor stator, the cleaning method of the motor stator is proposed, and the environmental friendliness, economy and safety of several cleaning agents are analysed. The scheme of crankshaft remanufacturing is proposed on the basis of the failure form of the crankshaft and the quality requirement of remanufacturing. Moreover, the process parameters are described. [ABSTRACT FROM AUTHOR]

The cause of crankshaft fracture crack of a certain vehicle has been analyzed through macroscopic analysis, microstructure analysis, mechanical properties test and dimension inspection. The analysis results show that: the fatigue strength of the crankshaft is reduced due to spheroidization recession, low strength and shallow nitriding layer of the fillets.

During the operation of diesel engines, the surfaces of the main and connecting rod journals wear out. Cracks of various locations are often found on the journals of the shafts. The article describes the analysis of the occurrence of cracks, the establishment of the causes of their occurrence and the determination of methods for the restoration of crankshafts with cracks. A magnetic flaw detector was used to detect cracks. The classification of cracks on the journals of diesel crankshafts into fatigue and technological ones is given. [ABSTRACT FROM AUTHOR]

Staircase testing is a standard method for evaluating the fatigue strength of components. However, staircase testing assumes a normal distribution, while components can display bimodal behavior due to flaws in material, or issues during the manufacturing process. Three unique step loading data sets on different production crankshafts provide evidence that step loading reliably identifies material or manufacturing issues, which lower a component's fatigue strength. Staircase testing has an 87% or greater chance of overestimating the component's fatigue strength, which in turn overestimates the component's expected reliability. For example, a component with a 99.9% reliability based on staircase testing would only have a 74% reliability based on step loading. If a component contains an undetectable manufacturing defect, staircase testing has a 99% chance of overestimating the component's fatigue strength. Step loading reliably improves the estimation of a component's fatigue strength distribution while providing insights into a component's defect tolerance. Highlights: Staircase testing overestimates a component's fatigue strength.Step loading reliably identifies issues that lower a component's fatigue strength.Step loading improves estimation of a component's fatigue strength distribution. [ABSTRACT FROM AUTHOR]

Taking the main bearing-main journal of a six-cylinder diesel engine as the research object，based on the elastic- -fluid lubrication theory and the micro-bump contact theory and considering factors such as journal misalignment and main bearing surface roughness，the main bearing lubrication characteristics model under the flexible whole body is established，and the influence of the main bearing surface profile on the main bearing lubrication characteristics and main journal vibration characteristics is analyzed. The results show that，compared with the result that does not take into account the main bearing surface profile，when the main bearing surface profile is included，the minimum oil film thickness of the main bearing is increased by 75.53%，the maximum oil film pressure is reduced by 6.15%，the average friction loss is reduced by 2%，the horizontal flexural vibration amplitudes of the main journal is reduced by 6%，the vertical flexural vibration amplitudes is reduced by 5%，and both the axial vibration and torsional vibration amplitudes are reduced by 2%. With the increase of the main bearing surface profile height，the minimum oil film thickness of the main bearing increases，the maximum oil film pressure decreases，the average friction loss decreases，and both the maximum roughness contact force amplitude and the number of occurrences are reduced; the amplitudes of flexural vibration，axial vibration and torsional vibration of the main journal are all reduced.

When developing the technological process of cast iron crankshaft restoring, it is necessary to obtain a martensitic structure in the pad weld in order to ensure the wear resistance needed. To form the martensitic structure the cooling rate after padding must be at least 80 - 90 °C / s. The helical surface welding does not lead to such a result, so in our research we use the welding according to the width of the shaft neck. We also examined the heat release from the pad weld and its cooling rate. For its implementation, the necessary calculations were made according to a compiled program in the QBASIC language. On the basis of these provisions, the theoretic background is proposed for the possibility of the wide-ringed welding of crankshaft necks, which ensures a minimal change in the structure and geometry of the crankshafts. [ABSTRACT FROM AUTHOR]

In the process of developing the vertical crankshaft comprehensive measuring instrument, owing to the problems of complex calculation and low efficiency of the existing crankshaft main journal cylindricity evaluation algorithm, a cylindricity error optimization algorithm based on step acceleration is proposed. As per the requirement of a measuring device of crankshaft, a mathematical model for evaluating cylindricity error is also proposed, and the cylindricity error in crankshaft journal with minimum assessment requirement is calculated by the step acceleration based optimization algorithm. Then, a certain type of engine crankshaft is taken as an object for detecting the main journal cylindricity error using the proposed new algorithm on the platform of a vertical crankshaft comprehensive measuring machine, and the measurement uncertainty analysis is performed. Compared to Talyrond290, the detection error of the measurement results is found to be within 0.5 um. In comparison with the geometric hexagon cylinder optimization algorithm, the results of the proposed methodology are found to be highly consistent and the computation time is reduced by 27.8%. Therefore, the proposed algorithm is practical. [ABSTRACT FROM AUTHOR]

Torsional vibration dampers in modern internal combustion engines are used to reduce alternating shear stresses leading to fatigue failure of the crankshaft, as well as to diagnose the crankshaft, reduce oil consumption, increase the mechanical efficiency of the engine, and reduce noise. Torsional vibration dampers are suggested to be used at OJSC “MINSK MOTOR PLANT” Holding Managing Company” to improve the technical level of four-cylinder diesel engines. Damper parameters choice is based on torsional system model research, which is equivalent to the torsional diesel system of a 4ЧН (4ChN) 11×12.5 diesel engine. The amplitudes of the crankshaft nose torsional vibrations with the engine running are calculated according to the full-load curve. It was found that the maximum amplitude of vibrations corresponds to the diesel engine operation at a rated speed of 1000 rpm. In this case the amplitude of twisting of the crankshaft nose is 0.123 deg. For this diesel engine operating mode, the moment of inertia of the liquid damper flywheel and the damping coefficient were determined. They ensure a decrease in the torsional vibrations amplitude by more than three times. The calculation determined the expected decrease in the torsional vibrations amplitude for other modes of engine operation according to the full-load curve. In the entire research of crankshaft rated speed, the amplitude of nose torsional vibrations when using a damper is three times lower than without it. For experimental refinement of the damper parameters, a damper design with a variable moment of the flywheel inertia, as well as the possibility of replacing the polymethylsiloxane fluid are proposed.

The factors of affecting crankshaft torsional fatigue strength and the causes of various torsional failure were analyzed by torsional fatigures test of crankshafts, and the corresponding improvement measures were put forward. It was pointed out that with the increase of engine explosion pressure, the torque of crankshafts increases accordingly, which leads to the increase of crankshaft torsional fatigue failures. The main torsional failure locations include pin journal oil hole, crank arm and pin journal bottom center of the crankshafts. The causes of failure are related to structural design, raw materials, machining, heat treatment and so on. The oil holes of pin journal are the most common part of torsional fatigue failures, and the crack sources are generally about 8~10 mm from the inner walls of oil holes to the journal surfaces. The torsional fatigue strength of crankshafts is more affected by induction hardening on the journal surfaces. The torsional fatigue strength of crankshaft reduces about 30% by surface induction hardening. The torsional fatigue strength of surface hardening crank shafts is increased more than 25% by polishing the internal surfaces of the oil holes. [ABSTRACT FROM AUTHOR]

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In recent decades, the electromagnetic induction quenching approach has been widely applied in the surface treatment process of steel engine parts such as crankshafts. In this paper, the strengthening effect of this approach was selected to be the object of study. First, the multi-physics coupling phenomenon was established by a 3D finite element simulation approach. Then, the fatigue property of the crankshaft was predicted based on the combination of the residual stress field obtained in the previous step and a chosen multi-axial fatigue damage model. Finally, a corresponding experiment verification was carried out to check the accuracy of the prediction. The results showed that the method proposed by this paper can provide high enough accuracy in predicting the fatigue property of two types of commonly used steel crankshafts. [ABSTRACT FROM AUTHOR]

In order to study on the vehicle’s dynamic behavior, this study presents a new dynamic modeling of the vehicle by considering the engine dynamics. The coordinate systems are considered separately for the sprung mass and unsprung masses. By using Newton’s equations of motion, the force-torque equations of the sprung mass and unsprung masses are derived in the vehicle coordinate system. In general, the sprung mass in modeling of the vehicle is considered as a rigid body. However, in this study the components rotation of the sprung mass such as the engine crankshaft is considered and its gyroscopic effects are exerted in the governing equations. The lateral and longitudinal forces of the tire are evaluated by Pacejka model. In fishhook maneuver, the vehicle's dynamic behavior is studied by the numerical simulation method under the supervision of the National Highway Traffic Safety Administration (NHTSA). The numerical simulation results are also validated by ADAMS/Car software. According to the results, the 15-DOF model in this research simulates the vehicle’s dynamic behavior with a good accuracy and the maximum roll rate of the vehicle reaches about 37 degrees per second.

This study describes the remanufacturing process scheme and key technologies of waste compressors. Firstly, the technical characteristics of compressors for home appliances such as refrigerators and air conditioners are summarised. Then, the remanufacturing process scheme is proposed with the waste refrigerator compressor as the research object. The purpose or requirements of key processes such as separation, disassembling, cleaning, detecting, remanufacturing and reassembling are also elaborated. Moreover, the corresponding remanufacturing technology or method is proposed to satisfy the structural, quality requirement, economy and environmental friendliness of products and components. The cleaning technology of the compressor motor stator and the remanufacturing technology of crankshaft is highlighted. In accordance with the structural and quality requirement of the motor stator, the cleaning method of the motor stator is proposed, and the environmental friendliness, economy and safety of several cleaning agents are analysed. The scheme of crankshaft remanufacturing is proposed on the basis of the failure form of the crankshaft and the quality requirement of remanufacturing. Moreover, the process parameters are described.

During measurements, the crankshafts of marine engines are usually supported on a set of rigid prisms. Such prisms maintain a constant height position, cause different values of reaction forces and, consequently, may cause elastic deformations of the crankshafts. Thus, the measurements of the dimensions and geometry of the crankshaft may be distorted. This article proposes a measuring system developed to support the crankshaft with a set of flexible supports. These supports implemented the given reaction forces, which ensured the elimination of the crankshaft deformations, regardless of the possible deviations, i.e., in the coaxiality of the main crankshaft journals. The values of these forces were calculated using the finite element method (FEM). These calculations showed that in order to eliminate the crankshaft deformations, the values of the reaction forces must change not only on individual supports, but also with the change of the shaft rotation angle during the measurement. The numerical experiments showed that the application of flexible supports results in uniform contact reaction forces on adjacent main journal supports. This uniformity occurs regardless of the quality of the crankshaft geometry. Thus, the necessity to use a set of flexible supports for measuring marine engine crankshafts was confirmed. The research also showed that the values of the reaction forces ensuring the elimination of shaft deflections under the assumption of nodal support can be treated as corresponding to the resultant reaction forces realized by the prismatic heads. [ABSTRACT FROM AUTHOR]

Threading is a process that generates internal and external threads, and it is widely used in various applications in industries as threads can be found in almost all industrial mechanical component assemblies due to precision and speed. In machining, threading is one of the most critical processes. The machining process focused on this study is responsible for the thread to fix the engine gear on the crankshaft. The modernization of internal combustion engines has required evolution concerning dimensional accuracy unprecedented in the mechanical industry and better mechanical and tribological properties at a low cost. One solution that has been researched in depth to overcome the threading machining problems is to use coated tools. Therefore, this study aims to analyze the performance of different thread tapping tools regarding cutting tool life cycle and wear mechanisms during the internal threading of a nodular iron engine crankshaft. The tools used were sintered uncoated High-Speed Steel – HSS-PM, coated HSS-PM (TiN), and HSS-PM (TiCN). The wear measurement on each cutting core was evaluated using a laser beam and calculated by a measuring equipment software. It was observed/shown that the wear mechanism for the HSS-PM tool is the plastic deformation with the formation of cracks in regions of the Co/Cr/C binder. Moreover, the tools coated with TiN and TiCN showed abrasive wear of the coating and localized peeling, especially at some zone where it had low substrate adhesion, tool wear. The sharp softening of the HSS-PM tool after fracturing in 2100 threads may be caused by the low temperature reached in the cut or the presence of W, V, and C in the microstructure. HSS-PM (TiCN) taps performed better than HSS-PM (TiN) (21% better), as well as uncoated HSS-PM (86% better). [ABSTRACT FROM AUTHOR]

In modern engineering, electromagnetic induction quenching is usually adopted in improving the fatigue performance of steel engine parts such as crankshafts. In order to provide the theoretical basis for the design of the process, correct evaluation of the strengthening effect of this technique is necessary. In this paper, the research aim is the strengthening effect of this technique on a given type of steel crankshaft. First the magnetic-thermal coupling process was simulated by a 3D finite element model to obtain information on the temperature field during the heating and cooling stages. Then the residual stress field after cooling was simulated based on the same model. At last, the fatigue property of this crankshaft was predicted based on the combination of three parameters: the KBM (Kandil–Brown–Miller) multi-axial fatigue model, the residual stress field and the fatigue strength of the material. The experimental results showed that this method can achieve a much more reasonable prediction than the traditional strengthening factor, and thus can be applied in guiding the design of the quenching process. [ABSTRACT FROM AUTHOR]

For critical steel engine parts, such as crankshafts, the fatigue strength under the critical working condition is usually improved by the electromagnetic induction quenching technique. In a previous study, the strengthening effect of this approach was always evaluated by a constant, which may result in some errors with the change of the technological parameters. In this paper, a type of steel crankshaft is selected to study the strengthening effect of this approach; first a local sub model composed of the crankpin is built to simulate the magnetic–thermal coupling process, then, the residual stress field is determined by simulating the whole course of fabrication. Finally, the prediction of the fatigue limit load is proposed based on the residual stress and the strength parameters of the material. The experimental verification shows that, when compared to the general means of modification models, the modified McDiarmid multi-axial fatigue model is more suitable to be applied to analyze the fatigue property of this quenched crankshaft due to the markedly higher accuracy. Based on this study, a new fatigue-limit load-prediction approach of this kind of crankshaft can be proposed for engineering applications. [ABSTRACT FROM AUTHOR]

With industrial advancement, the demand for precision parts is increasing. A crankshaft is the main part of an engine, which determines the life and quality of the engine, and is one of the precision parts whose demand is growing. Non-circular grinding is the grinding method used for crankshafts, and it is different from conventional grinding methods. In this study, the grinding force, considering the characteristics of the non-circular grinding, was obtained, and the bending and torsional deformation of the crankshaft caused by the grinding force was predicted. By applying the deformation to the grinding force, a real depth of the cut prediction model that can calculate the grinding force and predict the real depth of cut was proposed. A compensation model that can estimate the set depth of cut was proposed to obtain the desired real depth of cut. Various grinding characteristics related to force and deformation in non-circular grinding were analyzed. It was observed that the grinding force has different values at all grinding points, even if one pin is ground because the change in the workpiece velocity depends on the grinding point. Unlike in general grinding, the tangential force affects the depth of cut. The real depth of cut obtained through the prediction model proposed in this study differed from the set depth of cut by up to 45%. Comparing the compensation model of this study to the conventional method, the former showed approximately 20% improved compensation performance. [ABSTRACT FROM AUTHOR]

The cause of crankshaft fracture crack of a certain vehicle has been analyzed through macroscopic analysis, microstructure analysis, mechanical properties test and dimension inspection. The analysis results show that: the fatigue strength of the crankshaft is reduced due to spheroidization recession, low strength and shallow nitriding layer of the fillets. [ABSTRACT FROM AUTHOR]

This article is devoted to development of restoration procedure of diesel engine crankshafts and its application in OOO Tekhnoplazma. The main defects of crankshafts are described. The equipment, applied materials, and main modes of plasma facing are summarized. The quality of crankshaft restoration is evaluated. [ABSTRACT FROM AUTHOR]

In order to explore the influence of different working conditions on the surface morphology of crankshaft and connecting rod of compressor,the roughness meter was used to measure the surface morphology characterization value of connecting and crankshaft based on the compressor reliability test. The results show that the working conditions of the compressor have a great influence on the surface morphology of the crankshaft and connecting rod. With the increase of work time,the Ra value of compressor parts surface increases,but the Rzvalue of connecting rod surface decreases obviously. The start-stop of the compressor also has some influence on the surface morphology of the moving parts. With the increase of start-stop times,the values of Raand Rzof connecting rod surface decrease,while the values of Raand Rzof crankshaft surface increase slightly.Through analysis it can be known that the crankshaft and connecting rod are in normal wear stage after running 672 h and 1 344 h at 43℃ . The connecting rod is still in the initial wear stage and the crankshaft is in the normal wear stage after 125,000 and250,000 start-stop cycles respectively at 25℃ .

The main objective of this study was to conduct a new and simple but accurate analysis of the dynamics of a crankshaft-connecting rod system based on Lagrange's trigonometric identities. Actual and equivalent connecting rod mass approximations of single- and multi-cylinder reciprocating engines were studied. Several examples were studied to demonstrate the dynamics of the system. Lagrange's trigonometric identities were used to simplify the model, while MATLAB was used to obtain the results. For both the proposed reduced model and the full model, the resultant forces and torques of an actual and an equivalent connecting rod mass were compared. The results showed that the proposed reduced model gives force and torque results that match the results of the full model very well. It was shown that the largest torque imbalance resultant on the crankshaft was exerted by the two-cylinder engine. In addition, it was shown that the largest external forces resultant acting in the xdirection was exerted by the one-cylinder engine. The results also revealed that the resultant of external forces acting in the y-direction was zero for multi-cylinder engines. The relative error, which mainly occurred at the points of maximum force and torque, ranged from about 1% to about 15%. [ABSTRACT FROM AUTHOR]

Introduction. The technological features of the processing crankshafts by the vibration shock method of surface plastic deformation (SPD), which is widely used in the technology of manufacturing machine parts, are considered. Theresearch objective is to justify the efficiency of the influence of vibration shock hardening treatment on improving the quality and performance of crankshafts (CS).Materials and Methods. The methodological studies included the validation of the vibration shock processing flowchart and the development of an analytic model for assessing the effect of processing on the change in the macrogeometry (warpage) of the CS.Results. Flowcharts have been developed for volumetric vibration shock finishing and hardening treatment of CS using a vibratory machine with a U-shaped work chamber. Its overall dimensions measure alike or exceed the overall dimensions of the CS being processed, and ensure the location of the shaft in such a way that its main axis, coinciding with the axis of the main bearing journals, is in the zone of the conditional axis of working mass rotation. The surface quality parameters were investigated during their processing on the UVG 4X10 vibratory unit according to the proven techniques using the dedicated tooling. It has been established that the vibration shock hardening treatment (ViHT) enables, due to plastic deformation of microroughness, to obtain a qualitatively new surface microrelief and to reduce its initial roughness, to drastically increase the surface microhardness of the CS main and rod journals; at that, it changes the stressed state of their surface layer. A calculated dependence is proposed to assess the total warpage of the CS strengthened under the ViHT, and its adequacy is confirmed. It is shown that the warpage of the shaft after the ViHT is due to the different tension of the rod and main journals of the CS at the level of Кн ≈ 0.6.Discussion and Conclusions. Vibration shock treatment of CS provides an improvement in the geometric and physicomechanical parameters of surfaces of the rod and main journals. As a result of processing all surfaces of the shaft, warpage does not exceed the permissible values established by the technical requirements. So, we can conclude on the efficiency of the considered method of hardening CS with the aim of increasing their operational properties.

This paper deals with the stress analysis of crankshaft of a 4- cylinder internal combustion engine. The crankshaft is during its operation subjected to static and dynamic load. High frequency dynamic cyclic loading can lead to material fatigue and eventually fracture. To reduce this dynamic loading a new type of torsional vibration damper built in the crankshaft counterweight will be analyzed with the use of numerical simulation. After defining boundary conditions and applying loads, Von Mises stress analysis will be performed using the finite element method.

This article describes one of the possible ways for improving the energy efficiency of shunting diesel locomotives. It means a replacing a traditional traction electric transmission with a diesel generator set with a hybrid transmission with a free-piston internal combustion engine and a linear generator. The absence of a crankshaft in an internal combustion engine makes it possible to reduce thermal and mechanical losses, which, in turn, leads to an increase in the efficiency of traction electric transmission of the diesel locomotive.

The relevance of the work is due to the need to study the patterns of lubrication of the connecting rod bearings of the crankshaft of an automobile engine in order to exclude the influence of various factors on the risk of cranking the bearings - sudden costly failure The aim of the article is to increase the resource of automobile engines in operation by preventing failures in the form of crank bushings based on minimizing the effect on its oc¬currence of a process of breaking the oil flow to rubbing surfaces. Experimental studies in bench conditions based on the original method of breaking the oil flow using a motor unit based on the KamAZ-740.10 automobile engine were used as a methodological apparatus. Key results identified conditions for lubrication of connecting rod bearings; the minimum oil pressure values were obtained depending on the load-speed mode of engine operation, at which a flow break occurs and oil con rod bearings may starve. The scientific novelty of this article is that the oil flow rupture technique was first applied to investigate the conditions for the occurrence of a pre-failure condition of connecting rod bearings and to justify the diagnostic parameter of their limiting state. The practical importance in applying the oil flow discontinuation technique allowed substantiating the recom-mendation to exclude the oil distribution sleeve of a centrifugal trap from the crankshaft design of KamAZ engines because of its negative effect on lubrication conditions. Using the technique of breaking the oil flow, it is possible to further evaluate changes in the lubrication conditions of connecting rod bearings under the influence of operational aging and recovery processes, as well as measures to improve the lubrication system.

The hermetic compressor is widely used in household refrigerators. About 10% (10-15W) of the power consumption of the compressor is converted to heat due to the friction losses in the journal bearings, and about 76.4 million kWh of energy is spent on friction losses in the annual energy consumption of refrigerators sold in one year. In this work, the energy efficiency of the refrigerator compressor is increased by the reduction of friction losses in journal bearings. The model for kinematic and dynamic analysis of the crankshaft-connecting rod in the hermetic compressor is established to determine the forces acting on the crankshaft and the load-bearing capacity in journal bearings. For all these investigations, in-house built MATLAB codes are used. The results of the kinematic analysis are compared to the CAD analysis. The eccentric ratio for hydrodynamic lubrication conditions is determined. The bearing dimensions are optimized to minimize energy loss. [ABSTRACT FROM AUTHOR]

In order to meet the requirements of high accuracy in the synchronous measurement of the main journals and connecting rod journals of crankshaft measuring machines, a multi-probe measurement method and a Gaussian filtering with non-equal interval sampling were proposed. On the basis of synchronous measurement, a multi-probe measurement method was designed, which might add the measured data to eliminate the harmonics and achieve the goal of separating errors. According to the measuring processes of connecting rod journals, the real sampling angle distribution function was established, and the corresponding Gaussian weight function of each sampling angles was calculated. The weight function and the collected data corresponding to the angle were subjected to discrete cyclic convolution operation in the spatial domain to obtain the filtered effective circular contour data. Finally, the corrected measurement results were compared with the original measurement results. The measurement errors of the four connecting rod journals of the crankshaft is significantly reduced, and the accuracy is significantly improved. [ABSTRACT FROM AUTHOR]

Diesel engine anti-shock performance is important for navy ships. The calculation method is a fast and economic way compared to underwater explosion trial in this field. Researchers of diesel engine anti-shock performance mainly use the spring damping model to simulate the main bearings of a diesel engine. The elastohydrodynamic lubrication method has been continuously used in the main bearings of diesel engines in normal working conditions. This research aims at using the elastohydrodynamic lubrication method in the main bearings of the diesel engine in external shock conditions. The main bearing elastohydrodynamic lubrication and diesel engine multi-body dynamics analysis is based on AVL EXCITE Power Unite software. The external shock is equivalent to the interference on the elastohydrodynamic lubrication calculation. Whether the elastohydrodynamic lubrication algorithm can complete the calculation under interference is the key to the study. By adopting a very small calculation step size, a high number of iterations, and increasing the stiffness of the thrust bearing, the elastohydrodynamic lubrication algorithm can be successfully completed under the external impact environment. The calculation results of the accelerations on engine block feet have a similar trend as the experiment results. Diesel engines with and without shock absorbers in external shock conditions are calculated. This calculation model can also be used for diesel engine dynamics calculations and main bearing lubrication calculations under normal working conditions. [ABSTRACT FROM AUTHOR]

Through comprehensive analysis, crack propagated along the nitride in the form of planar clusters, which caused the metal to layer on the parting surface. There are deep decarburization layer on both sides of the crack of crankshaft blank, and the crack line is soft and thick. The process of quenching and cooling, only when the transformation amount of martensite reaches a certain amount, can cracks be formed. At such a low temperature, even if cracks occur, decarburization and obvious oxidation won’t occur on both sides of the cracks. If there is oxidation decarburization on both sides of the crack, it can be confirmed that the crack has existed before quenching, and the crack belongs to non quenching crack.

The cause of crankshaft fracture crack of a certain vehicle has been analyzed through macroscopic inspection, chemical composition analysis, microstructure analysis, hardness test, mechanical properties test and dimension inspection. The analysis results show that: All of its chemical composition, microstructure, hardness, mechanical properties and dimensions accord with the technical specifications. However, due to the bearing score of the seventh main journal and the wear of fillet, the crankshaft cracked at multi-points from the fillet. The reason is that the fracture of crankshaft is finally caused by large cyclic external force.