Crankshaft System Research Articles

Time-varying dynamic characteristic analysis of journal–thrust coupled bearings based on the transient lubrication considering thermal-pressure coupled effect

This work studied the time-varying dynamic coefficients of journal–thrust coupled (JTC) bearing within a diesel engine crankshaft system. A transient thermoelastohydrodynamic coupled lubrication model of JTC bearings was established by considering pressure, flow, and heat continuity conditions at journal–thrust interface. On this basis, the dynamic coefficients of three degrees of freedom were further calculated. A transient lubrication experiment was conducted on a test rig to validate the established model. Parametric analysis was conducted to explore the transient lubrication performance and the dynamic coefficient of JTC bearing under different input parameters. Moreover, for cases when the crankshaft undergoes large axial movement, the influence of the JTC bearing dynamic coefficients on the natural characteristics of crankshaft were further analyzed to provide an analysis method for crankshaft vibration characteristics.

Optimized design of silicone oil torsional damper for diesel generator

Abstract Due to the high cylinder pressure and high-performance requirements, the silicone oil damper of an inline six-cylinder diesel generator needs to be optimized to reduce the crankshaft stress. The centralized mass method was used to simplify the crankshaft system. A multi-body dynamic model was established, and the crankshaft stress and torsional vibration amplitude were simulated. The results show that the excessive shear stress at generator crank pin 5 is due to the resonance between the first-order intrinsic frequency of the shaft system and the 3rd harmonic torsional vibration. The shear stress was analyzed for different damper thicknesses and stiffnesses, and it was found that the shear stress at crank pin 5 was minimized when the damper thickness was 60 mm and the torsional stiffness was 250,000 N·m/rad. The torsional amplitudes at different speeds and frequencies were measured in the bench test, and the results were consistent with the calculations. The designed silicone oil torsional damper meets the requirements of the 2000-hour bench test.

OPTIMASI OPTIMASI PROSES PEMBERSIHAN BERAS: STRATEGI TERAPAN UNTUK PENINGKATAN KUALITAS HASIL PERTANIAN

This community service activity (PKM) aims to introduce and train the community to process their rice harvests using appropriate technology, in the form of a grain peeling machine. The main target of this PKM activity is the people of the Jaya Mandiri Farmers Group in Batu Layang Village RT.04/RW.15, North Pontianak District, who still have limited means for their agricultural activities. The methods applied in this PKM activity are science and technology diffusion, socialization, and active community participation. So that with this PKM activity, the community has gained knowledge and skills in processing their post-harvest rice products, and it is hoped that this can help overcome their productivity problems due to limited agricultural facilities. Cleaning rice not only aims to remove empty grains, dirt and other foreign objects, but also increases the selling value per unit weight, increases the efficiency of drying and processing post-harvest products and extends shelf life. The working principle of the automatic rice cleaning tool is that when the rice is in the main reservoir, it then goes down through a small gap so that when it comes down it is cleaned with a fan so that the dirt stuck to the rice is blown away and the clean rice enters the reservoir section. The construction of this rice cleaning machine is divided into a hoper as a place to input rice, a crankshaft system, while the drive system consists of an electric motor, pulley, belt, pegs, bearings. With this device, the process of cleaning rice can be carried out simply and easily, and the process time, namely cleaning time, is shorter. With a shorter processing time, the production rate per unit time becomes greater. Improving the quality of agricultural products is very important in supporting food security and farmer welfare. One of the key aspects in ensuring the quality of agricultural products is the post-harvest processing process, especially the rice cleaning process. In this context, this research aims to optimize the rice refining process through the implementation of effective applied strategies. This study was conducted through a comprehensive series of laboratory experiments and field tests. Refining methods involving a combination of traditional and innovative technologies were evaluated to find the most efficient strategy for improving rice quality. The research results show that the use of a combination of certain technologies can increase the efficiency of rice cleaning, as well as reduce yield losses and increase the selling value of the product. This research makes a significant contribution to the development of agricultural practices that are sustainable and oriented towards quality results. These findings have direct implications for farmers in increasing the competitiveness of their products in local and global markets, as well as in supporting government efforts to achieve national food security goals.

Eight-link pressure mechanism and its dynamic simulation based on improved ant colony algorithm optimization

Abstract In recent years, the optimization of eight-link pressure mechanism using ant colony algorithm is a research hotspot, but given the limitations of traditional ant colony algorithm, this paper improves the ant colony algorithm based on the SSA-IACO algorithm and develops the application and analysis of eight-link pressure mechanism and its dynamic simulation. Through the study of parameter settings before and after optimization, simulation analysis and other aspects, it is concluded that: the efficiency of the new scheme optimized by the improved ant colony algorithm is 88.86% higher than the original scheme. The stator power is reduced by 4.10% and the power factor is increased by 14.67% on average over the original scheme. The maximum magnitude of the free end torsion angle of the crankshaft system is 0.16 degrees, and the increased resonance speed is about 1800 rpm. The maximum torsion angle of the main harmonic (6th harmonic) is reduced from 0.54 to 0.16, and the damping effect is noticeable. When 0.7 ≤ ρ 0.8, and ρ is close to 0.7, the algorithm performs better. When 0.15 ≤ θ 0.2, and the value of θ is more comparable to 0.15, the algorithm obtains the optimal solution and the execution time is shorter than the [0.7,0.2] combination.

Torsional vibration attenuation of a closed-loop engine crankshaft system via the tuned mass damper and nonlinear energy sink under multiple operating conditions

In recent years, nonlinear energy sink (NES), as a nonlinear dynamic vibration absorber (NDVA), has been widely studied due to its high robustness and broadband vibration attenuation effectiveness, compared with the traditional linear dynamic vibration absorber (LDVA). In the area of crankshaft torsional vibration reduction, the external excitation of a closed-loop crankshaft model changes with the variation of speed, which puts forward higher requirements for wide-band torsional vibration attenuation. This study attempts to explore the feasibility of NES replacing the traditional linear tuned mass damper (TMD) for engine crankshafts in possible practical engineering application by studying a four-cylinders diesel engine crankshaft. Firstly, a multi-inertias nonlinear closed-loop self-excited coupled oscillation model (M-NCSCO) of crankshaft is established, and the correctness of the model is verified through comparison with those from experiments. Based on this, the crankshaft is coupled with optimal TMD (O-TMD), general NES (G-NES), and optimal NES (O-NES), respectively. An improved Newmark–β method is proposed to solve the nonlinear dynamic model numerically. The effects of NES and TMD on the vibration attenuation behavior of the crankshaft are studied under different engine operating conditions (including power, injection timing, single cylinder flameout, and load). The results show that the vibration attenuation efficiency and robustness of G-NES are 7.90% and 3.47% higher than that of O-TMD when considering the above four typical working conditions comprehensively. After further optimization of G-NES, the vibration reduction efficiency of O-NES is improved by 3.1% compared with G-NES.

Analysis of rigid-flexible coupled torsional vibration and vibration suppression of crankshaft system under multiple working conditions

With the rapid development of shale gas resources in China, there is an increasing demand for large and multiple column compressors. However, this development has brought to light the issue of torsional vibration in compressor crankshaft systems, particularly under variable loads and multiple working conditions. In order to reduce the torsional vibration of the compressor crankshaft and ensure the safe and stable operation of the compressor unit, this study proposes a method for calculating and suppressing torsional vibration in the crankshaft system of a shale gas compressor, which takes into account the flexibility effect of various parts and considers multiple working conditions. The analysis focused on the rigid-flexible coupling torsional vibration characteristics of the crankshaft system under multiple working conditions, considering the flexible deformation of the main bearing, connecting rod, and crankshaft. The study successfully determined the torsional vibration response of the crankshaft system under seven typical working conditions. Furthermore, for the worst conditions, a detailed analysis of the vibration response of the crankshaft system was conducted and carried out a study on suppressing crankshaft torsional vibration through response surface optimization design. The study findings indicate that the compressor system exhibits low-frequency vibrations during operation. The maximum torsional angular deformation at the crank pin of the fourth column is measured to be 0.052°. Following structural optimization, the relative torsional angular deformation of the crank pin is reduced by 25.61% under the worst operating conditions. Moreover, the peak angular velocity of the center of mass is reduced by 22.17%. These results demonstrate a significant suppression effect on torsional vibrations in the compressor crankshaft system, leading to improved working safety.

Semi-active control of crankshaft skyhook based on magnetorheological torsional damper

The purpose of this study was to solve the problem that the damping of rubber or silicone oil torsional dampers used in crankshafts is not adjustable and cannot effectively control torsional vibration at different resonant frequencies. Based on the controlled rheological properties of magnetorheological (MR) smart materials, this study designed a new type of variable damping MR torsional damper (MRTD) and proposed a semi-active control method to effectively control the torsional vibration of the crankshaft under multiple harmonic resonances. First, a mechanical model of the MRTD and a lumped parametric mass model of the crankshaft system were developed, and the resonance frequency harmonic range of the crankshaft system operation was determined by the torsional vibration characteristics analysis. Then a semi-active skyhook control method for the MRTD was proposed, and a joint control simulation analysis was performed using Amesim and Matlab software. The torsional vibration control effects of the crankshaft system with no damper, MRTD with different damping coefficients, and MRTD with skyhook control under acceleration and uniform speed conditions were comprehensively investigated. The simulation results indicated that the skyhook damping control significantly reduced the torsional vibration amplitude under both acceleration and uniform speed conditions, verifying the effectiveness of the skyhook-based control strategy for MRTD.

Analysis of the influence of piston–cylinder friction on the torsional vibration characteristics of compressor crankshaft system

With the development of compressors toward high speed and multiple columns, the torsional vibration phenomenon has become a major factor affecting the service life and reliability of the shaft system. Therefore, this paper considers the influence of friction between piston and cylinder on the instantaneous inertia of the crank connecting rod mechanism, establishes a nonlinear torsional vibration mechanics model of shale gas compressor shaft system, solves the natural frequency of the shaft system under undamped and damped conditions using the eigenvector method, and investigates the influence of the friction coefficient between piston and cylinder and the operating speed on the torsional vibration response of the shaft system under the self-excitation of the shaft system and the action of and excitation moment by the Runge–Kutta methods. The results show that after considering the friction between the piston and the cylinder, the second-order natural frequency of the shaft system shows a "high-low–high" fluctuation pattern. As the friction coefficient increases, the amplitude of the shaft system and the peak vibration speed show a rising trend. Meanwhile, when the speed increases, the vibration of the shaft system changes from chaotic \ period to the proposed periodic state, but the amplitude shows a decreasing trend. The research in this paper aims to improve the theory of nonlinear dynamics of compressor shaft systems, and the determined nonlinear parameters can be used to guide the operation and maintenance of compressors in engineering.

Comparison of an opposed-piston free-piston engine using single and dual channel uniflow scavenging

• The OP2S-FPE using single-channel and dual-channel uniflow scavenging was proposed. • The CFD model of the engine was built, and simulation parameters were discussed. • The single-channel engine has advantages of fast heat release rate and low emission. • Energy loss comparisons between the single and dual channel engine was presented. • The single-channel uniflow scavenging combustor is suitable for the engine. The free-piston engine is an unconventional engine characterized by a free-moving piston without a crankshaft system. The scavenging process recharges the engine and is crucial to mixture formation and stable combustion. In this paper, a single-channel structure for a two-stroke opposed-piston free-piston engine was proposed. A comparative study of spray, combustion, emissions and energy balance was presented using computational fluid dynamics simulations. Grid independence and step sensitivity were discussed in order to improve the simulation accuracy. The results show that the combustion efficiency of the engine with single-channel structure increased to 98.1%, and the combustion duration decreased by 59.8%. Due to the successful combustion organization, the single-channel engine achieves low emissions even if the CO2 content is slightly higher. The thermodynamic analysis of the engine reveals that the energy loss from scavenging process contributes the largest part to the total energy loss. In addition, the study initially reveals the performance stability of the single-channel engine under different combustion conditions.

A Review of Dynamic-Tribological Simulation Methods for Sliding Bearings in Internal Combustion Engines

The problem of friction reduction and wear resistance of sliding bearings is one of the key factors in determining the overall performance of internal combustion engines. This paper investigated and summarized the theoretical and simulation models of multi-body dynamics of crankshaft system, tribology of sliding bearings, and the wear calculation methods of the shaft-bearing friction pairs. Existing studies show that the dynamics model, hybrid lubrication model, and the friction and wear models request to be upgraded by comprehensively considering the material, structure, manufacturing process, working conditions, and etc. Based on the research status and existing problems of the above analyses, this paper summarizes the simulation models applicable to the field of dynamics and tribology of sliding bearings and presents the prospects for optimization of wear calculation methods for sliding bearings.

Static and modal analysis of a crankshaft reciprocating driver for reciprocating-airfoil (RA) driven VTOL aircraft

New modes of transportation systems are under intensive development because traditional systems fail to become mass transportation means due to their technological limitations. To meet the growing demand for VTOL vehicles, a novel VTOL technology, reciprocating-airfoil (RA) driven VTOL aircraft, had been introduced. The objective of this study is to model a crankshaft to structurally determine the feasibility of using a crankshaft structure as the reciprocating driver of this novel VTOL technology. Unlike the conventional crankshaft IC engines or compressors, the crankshaft system herein is a reciprocating driver to generate long-stroke reciprocating motion of the wings for VTOL vehicle operations. The unique challenges of this study are the exceedingly long crank arms and stringent weight minimizations that require the use of high-strength carbon fiber materials. The crankshaft model is geometrically designed by using SOLIDWORKS design software, and the commercial Ansys Mechanical Solver has been selected for the FEM structural analysis. Based on the nonlinear static analysis results, the maximum stress is developed at the junctions between the main shaft and the middle crank web. However, all of the determined deformation, stress, and strain under the current loading conditions as well as weight requirement is acceptable. Also, according to the modal analysis result, the possible resonance chance is low. In conclusion, this study provides a pathway for the final development of the novel reciprocating airfoil VTOL technology.

Simulation Study on the Influence of Single Balance Shaft Mechanism on Noise Radiation of 3-Cylinder Engine

In this paper, simulation work was conducted to evaluate the vibration and noise of a 3-cylinder diesel engine. The finite element model of the whole engine and the dynamic model of the crankshaft system were established respectively. The boundary element method and the modal-based acoustic transfer vector (MATV) method were used to calculate the acoustic and vibration response, and the characteristic points were selected to monitor the radiated noise in the external acoustic field. Finally, through the structural optimization of the diesel engine model, the influence of adding a single balance shaft on the sound radiation of the whole machine was analyzed. The research results of this paper will provide technical support for the design of shock absorption and noise reduction of 3-cylinder engine in the application of unmanned ground vehicles (UGV), outboard engine, Unmanned Aerial Vehicles (UVA) and hybrid power system.

The torsional vibration simulation of the diesel engine crankshaft system based on multi-body dynamic model

In order to analyze the torsional vibration of the crankshaft system, a three-dimensional model of the crankshaft system is established, consisted of the piston, connected rod, crank shaft, flywheel and silicone oil damper. Use by multi-body dynamics simulation software ADAMS, created the multi-body dynamics model of the multiple degrees of freedom consisting of rigid hybrid engine system, to do the torsional vibration response simulation, analysis of the torsional vibration on the crankshaft. Through the torsional vibration test of the diesel engine crankshaft system, the accuracy of the simulation calculation results have been verified. This simulation result has higher accuracy, and this calculation method has certain engineering application value.

Advances in free-piston internal combustion engines: A comprehensive review

Free-piston internal combustion engines (FPICEs) have many potential advantages, such as simple structure, high conversion efficiency, multi-fuel feasibility and multi-output power types, because their piston motion is not restricted by the crankshaft system. Therefore, FPICEs have received considerable attention worldwide for many decades. According to recent research, the typical types of FPICEs include free-piston internal combustion engine linear generator, hydraulic free-piston internal combustion engine, linear Joule engine generator, and miniature FPICEs. This paper mainly reviews recent advances in these types of FPICEs. Firstly, the early research progress of FPICEs is briefly introduced. After that, the recent advances in the typical types of FPICEs are reviewed in more detail. These included the operating principles, piston dynamic characteristics, performances and control strategies for different types of FPICEs. Finally, the research trends and future development of FPICEs are discussed. It is noted that there are numerous research prospects for each type of FPICE, including performance optimisation, development of appropriate control systems, and future application exploration.

A Study on the Modeling and Simulation Method of Torsional Vibration Considering Dynamic Properties of Rubber Parts for Engine Crankshaft System with Rubber Damper Pulley

A Study on the Modeling and Simulation Method of Torsional Vibration Considering Dynamic Properties of Rubber Parts for Engine Crankshaft System with Rubber Damper Pulley

AN OPTIMAL FEEDBACK LINEARIZATION APPROACH FOR SOFT LANDING OF ELECTROMECHANICAL VALVE ACTUATOR IN CAMLESS INTERNAL COMBUSTION ENGINES

The fuel efficiency, maximum torque and power, and pollutant emissions of internal combustion engines have improved rather than conventional crankshaft system. These improvements are the result of replacing the crankshaft with a camless actuation technology. Soft landing, tracking the desired trajectory, valve seating in a low velocity and having a small time for valve opening and closing are some of the main conflicting objectives in camless engines. Due to the nonlinear model of the system, feedback linearization control is presented for dealing with the system challenges in this paper. Moreover, to optimize the system response, the concept of feedback linearization control is incorporated into the linear quadratic tracker and makes the proposed structure named FLQT. The simulation results indicate the optimal feedback linearization controller has a good performance in the realization of desired goals of the system.

The uncertain optimization algorithm to suppress vibration of the crankshaft system with random-interval hybrid variables

This study proposes a new uncertain optimization algorithm to suppress vibration of the crankshaft system. In this new algorithm, the interval expression with random-interval hybrid variables is obtained by the confidence level. In addition, the interval order relation, interval probability, radial basis function neural network technology, and multi-objective genetic algorithm are applied to construct uncertain optimization algorithm with random-interval hybrid variables. Moreover, typical examples are used to demonstrate the effectiveness of the proposed algorithm. To suppress vibration of the crankshaft system, the optimization–Latin hypercube sampling design is used to obtain the experimental scheme and the data sampling is performed by multi-body system simulation of the vibration performance. Then, the radial basis function neural network is built considering the torsional displacement and transient stress of the crankshaft. Finally, the uncertain optimization algorithm is operated on the crankshaft structure design of the high-power reciprocating compressor. The results demonstrate that the robustness of the vibration performance and strength property is improved through the uncertain optimization algorithm, compared with that through deterministic optimization. The uncertain optimization algorithm to suppress vibration of the crankshaft system with random-interval hybrid variables is an efficient and effective approach, which is finally proved by the prototype test.

Intelligent Diagnosis of V-Type Marine Diesel Engines Based on Multifeatures Extracted From Instantaneous Crankshaft Speed

This paper presents an intelligent combustion fault diagnosis approach for V-type marine diesel engines with uneven firing intervals based on the instantaneous crankshaft speed (ICS). First, experimental ICSs of a 16-cylinder marine diesel engine under normal and different degrees of fault conditions are investigated to obtain the most sensitive fault features. A new polar representation method named cyclic-polar-map (CPM) is proposed to effectively demonstrate the fault features. The quantitative radii of the CPM are used to indicate the location and degree of fault. Then, a support vector machine (SVM)-based intelligent fault diagnosis system is developed for automatically detecting the combustion faults with the features extracted from the proposed CPM and the frequency analysis of ICS. In addition, for the SVM training set is not always available in practice, a dynamic model of the crankshaft system is developed to simulate different fault patterns. Finally, the efficiency of the proposed intelligent diagnosis approach is validated by experimental data. The results show that the proposed SVM-based intelligent diagnosis system using both CPM features and frequency domain features of the ICS can obtain good accuracies under different fault degrees at various speed and load conditions.

Modal analysis of flying shear crankshaft system architecture

When flying shear works, the crankshaft will bear periodic load. If the size of the crankshaft is unreasonable, flying shear will produce strong resonance, which will lead to structural damage of the crankshaft system and flying shear failure. Through the dynamic analysis of the flying shear crankshaft structure, the natural frequency of the crankshaft is obtained, and the stress distribution cloud of the crankshaft under four stages is analysed. Finally, the weak links of the crankshaft are obtained through static analysis, and the solutions are put forward. The research in this paper is of great significance for improving the service life of flying shear crankshaft structure, and provides a basis for further theoretical research.

Modal analysis of flying shear crankshaft system architecture

When flying shear works, the crankshaft will bear periodic load. If the size of the crankshaft is unreasonable, flying shear will produce strong resonance, which will lead to structural damage of the crankshaft system and flying shear failure. Through the dynamic analysis of the flying shear crankshaft structure, the natural frequency of the crankshaft is obtained, and the stress distribution cloud of the crankshaft under four stages is analysed. Finally, the weak links of the crankshaft are obtained through static analysis, and the solutions are put forward. The research in this paper is of great significance for improving the service life of flying shear crankshaft structure, and provides a basis for further theoretical research.