Crank-connecting Rod Mechanism Research Articles

Equivalent Simulation Study of Delta-Rotor Engine

The mechanical structure, movement mode, and combustion process of a triangular rotor engine differ from those of a conventional engine with a crank connecting rod mechanism as the core. This makes it impossible to directly use existing simulation software to simulate the performance of the entire engine, rendering it difficult to conduct structural evaluation and performance prediction during the engine development stage. Therefore, using existing performance simulation software to establish a performance-equivalent model for a triangular rotor engine is crucial. To solve the above problems, this study proposes a performance-equivalent simulation modelling method for a triangular rotor engine based on a three-dimensional simulation model and the operating principles of the triangular rotor and four-stroke engines. Compared to various performance indicators obtained from the three-dimensional simulation model, the results show that the equivalent model established in this study has sufficient accuracy for key indicators such as the cylinder pressure, cylinder temperature, and in-cylinder quality under various working conditions. This can satisfy the requirements of the complete machine-performance simulation of a triangular rotor engine.

Reliability Analysis of Diesel Engine Connecting Rod Threaded Connection Based on ANSYS

Connecting rod bolt is the key component of the diesel engine crank connecting rod mechanism, and the phenomenon of stress concentration at the thread easily occurs in the working process of the crank connecting rod, due to the characteristics of the threaded connection. In order to improve the quality of the threaded connection of the diesel engine connecting rod, the connecting rod’s big end threaded connection structure is numerically simulated based on ANSYS finite element analysis software through the combination of theoretical analysis and numerical simulation. The stress distribution of different pitches, threaded connection length and bolt preload are analyzed, and the effects of different factors on the strength of threaded connection structure are obtained. The research results have important engineering application value for improving the reliability of the threaded connection and ensuring the safe operation of the diesel engine connecting rod mechanism.

Structural Optimization Design and Strength Test Research of Connecting Rod Assembly of High-Power Low-Speed Diesel Engine

The connecting rod assembly of a high-power low-speed diesel engine has high quality and high cost. If the connecting rod component is damaged, the whole machine may be paralyzed, resulting in serious economic losses and safety problems, so it is necessary to carry out strength analysis and structure optimization, reduce the failure rate, and increase its life. This paper takes the connecting rod of a low-speed diesel engine as the research object, builds the crank connecting rod mechanism model, and carries on the strength simulation analysis through professional simulation software. During this period, the accurate S-N curve of connecting rod material is obtained through a fatigue test, and the static strength test of the connecting rod assembly is carried out by an electro-hydraulic servo universal testing machine. The numerical modeling is validated based on the test results. Therefore, the influence of the structural parameters of the cross-section and the large end transition fillet on the stress of the connecting rod is analyzed. The results show that optimizing matching between the large end fillet of the connecting rod and the long diameter of the rod section not only reduces the mass but also improves the safety factor. After optimizing the structure of the connecting rod, the mass of the connecting rod is reduced by 5.85%, the maximum stress is reduced by 13.7%, and the safety factor is increased by 16.0%. In addition, due to the low-speed diesel engine connecting rod assembly weight is big, and the simulation computation efficiency is low, this paper by studying the influence of the cross-section parameters of the rod body and the large end transition fillet on the stress of the connecting rod, fitted the empirical formula calculating the maximum stress of connecting rod, for this model and similar type in the conceptual design, technology design provides a new analysis method, improved the efficiency of structural optimization and strength analysis of connecting rod assembly, filled the research gap of strength analysis and structural optimization of low-speed diesel engine connecting rod.

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.

Fatigue Strength Detection Method for Crankshaft of Vehicle Internal Combustion Engine Based on Dynamics

To accurately determine the load boundary conditions required for the finite element calculation of crankshaft fatigue strength, a dynamic-based fatigue strength detection method for the crankshaft of the automotive internal combustion engine is proposed. Taking a certain type of automotive internal combustion engine as the research object, the multi-body system dynamics model of crank-connecting rod mechanism is established and the dynamic load spectrum of a crankshaft in a working cycle of the internal combustion engine is obtained through dynamic simulation analysis. The load boundary conditions of crankshaft finite element analysis are obtained and the finite element model which can simulate the contact state between crankshaft and bearing is established. The crankshaft fatigue strength is based on the dynamic load spectrum. Degree detection provides load boundary, the fillet sub-model is constructed and the stress distribution of the fillet sub-model under 12-unit displacement loads is obtained by calculating the stress field. The working fatigue safety factor of the crankshaft under dynamic stress is calculated. The analysis results show that the detection error of the proposed method is less than 5% under different noise intensities and the average energy consumption is lower than that of the comparative detection methods, which are 251.37 J and 617.37 J respectively and shows that the proposed method has strong anti-interference and low energy consumption.

Motion simulation design of crank-connecting rod mechanism of automobile engine

In this paper, the crank-connecting rod mechanism of Santana 2000AJR automobile engine is modeled by UG8.0 software with CAD technology, and then the motion simulation module is used to create the motion drive. After pre-processing and post-processing, the motion simulation design of the crank-connecting rod mechanism is completed. In the development of automobile, the motion simulation technology can simulate the motion law of crank-connecting rod mechanism and replace the complicated physical experiments in practice, shorten the calculation cycle and cost, and lay a foundation for optimizing the design of crank-connecting rod mechanism.

Numeric simulation of the pulsation bottle for a reciprocating compressor in dynamic regime

The pulsation bottles are mounted at the inlet and outlet of / from the reciprocating compressor cylinders to even out the gas parameters (pressure and temperature). They ensure stable working conditions in the compressor cylinders and eliminate / reduce vibrations. The sizing of the pulsation bottle is done based on the geometric parameters of the compressor, the volume efficiency and working pressure. The use of a dynamic model made in the LMS Amesim program allows the study of a compressor with a set of pulsation bottles at the modification of: the pressure and temperature at the inlet / outlet of the compressor, the speed of the compressor the volume of the dead space and blocking or removing of the valves. The model includes the compressor cylinder with the corresponding dead spaces, the compressor valves, the suction and discharge pipelines and crank connecting rod mechanism. The simulation takes into account of the: gas composition, temperature and pressure in the system. The variation of the pressure in the bottles can be checked under these conditions. The values of the disturbing forces for a range of working and adjustment parameters can be obtained, values that can be used in a dynamic analysis according to API 618.

Estimation of Design Parameters of the Crank-Connecting Rod Mechanism of Engines for Mobile Agricultural Machines

An accurate choice of the design model of the crank-connecting rod mechanism of piston internal combustion engines affects the accuracy of the calculation results and their complexity. At present, most of scientists and technicians choose a two-mass design model to analyze the operation of the crankconnecting rod mechanism. The model considers only the rotational and reciprocating movements of two masses, which are connected by a rigid weightless rod. This model significantly simplifies the calculations, neglects the elastic deformations of the parts of the crank-connecting rod mechanism, and eliminates the need for compiling the equations of dynamics in partial derivatives. However, the model has a number of drawbacks. The calculation results obtained using the two-mass model exhibit significant errors, which mainly depend on the design features of the connecting rod assembly. The paper discusses multi-mass design models, where the connecting rod assembly can comprise several lumped masses located along its length. In this case, the plane-parallel motion of these masses is added. The masses have weightless and absolutely rigid bonds. Forces and moments acting on the piston assembly and the crank are calculated according to the equations compiled. Comparison of the calculation results with the results obtained for a two-mass model can be used to determine errors and choose a design model that provides the required accuracy. The considered design model is of interest to engineers and technicians engaged in the design and calculation of the crank-connecting rod mechanism of piston internal combustion engines.

Analysis of Design Parameters of a Novel Modified Reciprocating Mechanism

In this study, displacement, velocity and acceleration equations were obtained for the mechanism created by modifying the long-stroke reciprocating mechanism. Thus, a novel mechanism has been created. In addition, the effects of the design parameters were examined and the results obtained were compared with the conventional crank-connecting rod mechanism. While the crank radius (r) and connecting rod length (L), which are the main design parameters of the conventional crank-connecting rod mechanism, are fixed, the design parameters of the novel mechanism are changed and the effects of these design parameters on the velocity and acceleration characteristics are examined. For the novel mechanism, the ratio of the inner gear radius to the pinion gear radius (r2/r1=k) and the ratio of the output gear radius to the pinion gear radius (r0/r1=m) are determined as the basic design parameters. Accordingly, by decreasing k and increasing m, it was seen that the connecting rod angle, mean piston velocity, and mean piston acceleration were decreased. The correct choice of k and m shows that the novel mecha-nism can be made more advantageous compared to the conventional crank-connecting rod mechanism. The results are predicted to be promising for engine designers.

Review of recent advances of free-piston internal combustion engine linear generator

Free piston internal combustion engine linear generator (FPELG) is a novel energy conversion device. Compared with traditional rotary internal combustion engines, FPELG shows many potential advantages due to the elimination of crank-connecting rod mechanism, such as structure simply, the high thermal efficiency, the low emission, the multi-fuel and the multi combustion mode feasibility. Therefore, the FPELG has become a research hot-point in recent years and has achieved a lot of research results. This paper mainly discusses and summarizes the recent technical advances of the FPELG from the research groups worldwide. After a brief introduction on the early research of the free-piston internal combustion engines, its working principle and different configurations are introduced respectively. Then, this paper mainly focuses on the recent research progress of the FPELG from the aspects of modeling and simulation method, experimental approach, and control strategies development. In the end of the paper, the research trend and future development of the FPELG will be prospected. It is concluded that matching and optimizing performances of free-piston internal combustion engine and linear generator are the key research points, and the controlled piston trajectory of the FPELG is the key technology.

Design of A Dual-rotor Engine Driving by the Elliptic Gear

Aiming at the shortcomings of the crank-connecting rod mechanism engine, such as low transmission efficiency and high side pressure between the piston and the cylinder, the paper proposes a kind of dual-rotor engine driving by the elliptic gear. The left and right rotors are driven by the gas pressure in the cylinder, and then the elliptic gears on the output shaft are driven by the circular gears and the elliptic gears on the intermediate shaft. When the gears rotate, the output shaft connected outputs power again and again. The rotor rotates one circle, the four “cylinders” separated by the rotor work one time respectively, and the output shaft rotates two circles. The results of the calculation and the simulation test show that the serialization design can be carried out by setting different parameters of the long half-axis and the eccentricity. When the value of the long half-axis (100mm in this design) is fixed and the eccentricity is 0.4, 0.6 or 0.8, the rotation angle and the speed of the left and right rotors change obviously. The greater the eccentricity, the greater the difference of the rotation angle and the speed of the left and right rotors. The higher the compression ratio of engine, the higher the transmission efficiency.

Simulation and experiment research of vibration characteristic on star compressor

Aiming at the vibration defects of star compressor, simulation and experiment are carried out to investigate the compressor. By drilling holes in the valve stem, the pressure changes of each cylinder are measured without damaging the cylinder block. The dynamic model of crank-connecting rod mechanism is established. After the measured cylinder pressure loaded on the dynamic model, the force acting on the main motion pair is obtained. The finite element model of the compressor is established for the first time, the force of the motion pair is loaded on the finite element model by MPC coupling method, and the vibration acceleration of the machine base is tested. The result shows that the main modal shapes between 50-150 Hz are body deformation, modal shapes between 150-200 Hz are base deformation, the simulation acceleration of the base is higher than that of the experiment, and the main working frequency and frequency doubling can correspond. The conclusions provide reference for vibration isolation design of star compressor.

Design and output performance of vibration energy harvesting triboelectric nanogenerator

With the advent of global warming and energy crisis, the search for renewable energy to reduce carbon emissions has become one of the most urgent challenges. Ithas become a research hotspot to collect or harvest various mechanical energy in nature and convert it into electric energy. Vibration is a common form of mechanical movement in our daily life. It is visible both on most working machines and in nature and is a type of potential energy. There are several methods that can convert such mechanical energy into electric energy. Triboelectric nanogenerator (TENG) based on the principle of contact electrification and electrostatic induction which first appeared in 2012 by Zhonglin Wang provides a feasible method of efficiently collecting the vibrational energy with different vibrating frequencies. In this paper, a contact-separation mode of TENG is designed and implemented. The voltage- quantity of charge- distance(V-Q-x)relation of TENG is calculated. During the experiment, the factors such as load resistance, vibration frequency, etc. which affect the output performance, are considered and analyzed. An electrically driven crank-connecting rod mechanism is employed to provide the vibration source with adjustable frequency in a range of 1-6 Hz. The result shows that the amount of charge transfer in each working cycle remains almost unchanged, while the voltage and current increase with frequency increasing. When the frequency is 5 Hz, the best power matching resistance of the TENG is about 33 MΩ and the maximum output power reaches 0.5 mW. For a further study, a COMSOL software is used to simulate the distribution rule and variation rule of the electric potential in the contact-separation process, then the theoretical charge density and the experimental charge density on the polymer surface are compared and analyzed in order to provide theoretical and practical support for the design of TENG with collected vibration energy and self-powered vibration sensor. The result shows that the electric potential is proportional to the distance between two friction layers. While as the distance between two friction layers increases, the electric potential and the charge density both show a tendency to concentrate in the middle of the friction layer. The huge difference between experimental result and the simulation predicts thatmuch work should be done continually to improve the output of the TENG. Finally, the obtained results conduce to understanding the contact electrification and electrostatic induction mechanism and also provide a new method of harvesting the vibration energy.

Dynamic characteristic analysis of crank connecting rod mechanism in star-type air compressor

Dynamic characteristic analysis of crank connecting rod mechanism in star-type air compressor

Resonance analysis of opposed piston linear compressor for refrigerator application

ABSTRACTThe opposed piston linear compressor is considered to be the future of silent, reliable and efficient compression technologies. For long valves, less linear compressors have been widely used in cryocoolers for space applications. Recently research has established its high-performance characteristics which are useful in household refrigeration application. Unlike reciprocating compressors which are driven by rotary motors and need a crank connecting rod mechanism to convert rotary into linear motion, a linear compressor is driven by a linear motor which reduces the number of moving parts. This feature makes the compressor more reliable, more efficient and has a silent operation. The piston (suspended on spring stiffness) in the linear compressor is a free piston, i.e. motion of the piston is not constrained hence the performance of the linear compressor is highly dependent on system resonance. Free piston motion offers the unique advantage of ease of modulation, i.e. the stroke of the compressor and hence the delivery mass flow rate coming out of the compressor can be easily controlled by changing the supply voltage. Resonance in the linear compressor is a function of moving mass, spring stiffness and operating or electrical frequency. Achieving resonance in the linear compressor results in maximising the cooling performance of the refrigerator and minimising the input power requirement and hence an increase in the COP of the refrigeration system. The present paper discusses the results from resonance testing of the opposed piston linear compressor for household refrigerator using the fast Fourier transformation analysis. There are different parameters that are considered to optimise the natural frequency of the opposed piston linear compressor, consisting of frequency, moving mass, and spring stiffness. The piston performs compression and suction in a similar manner as in the conventional reciprocating compressor. An opposed piston linear compressor exhibits high energy efficiency due to its simple construction and less moving parts, its mechanical losses are much less than the reciprocating compressor.

Design and analysis of the electronic helical guide controller

This paper presents an Electronic Helical Guide Controller (EHGC) for the helical gear shaping process. Considering that the pinion cutter’s reciprocating movement is driven by a crank-connecting rod mechanism in most traditional gear shaping machines, this study adopts this kind of gear shaper as the machine platform to establish an accurate mathematical model. Then, the helical guide movement control algorithm is embedded in the interpolation module of the gear shaping CNC system using the electronic gearbox techniques to realize the special multi-axis linkage control requirements of the helical gear shaping process. The crankshaft’s angular position is measured by the internal sensor, so the rotational speed could be calculated online in each interpolation control cycle. The actual position and the velocity of the shaper cutter along the Z-axis are calculated using the kinematic model of the crank-connecting mechanism, at the same time, the motion of the other axes is controlled by the electronic gearbox. The proposed EHGC is low cost and very easy to implement in practice since it does not need a linear grating ruler and a probe on the Z-axis. The gear machining accuracy can also be estimated online by the EHGC, so as to guide the selection of the process parameters and improve the production efficiency. Experiments are performed to verify the effectiveness of the proposed EHGC.

An air-standard finite-time heat addition Otto engine model

A classical thermodynamic model for spark-ignited internal combustion engine simulation in which the heat addition process that takes a finite amount of time to complete is presented along with an illustrative parameter sensibility case study. The model accounts for all air-standard Otto cycle parameters, as well as crank-connecting rod mechanism, ignition timing, engine operating speed, and cumulative heat release history parameters. The model is particularly suitable for engineering undergraduate education, as it preserves most of the air-standard assumptions, while being able to reproduce real engine traits, such as the decay of maximum pressure, power, and thermal efficiency at higher engine operating speeds. In terms of complexity, the resulting finite-time heat addition Otto cycle sits between the classical air-standard Otto cycle and the more involved air–fuel Otto cycle, that are usually introduced on more advanced mechanical engineering courses, and allows students to perform engine parameter sensibility studies using only classical, single phase, pure substance, undergraduate engineering thermodynamics.

Integrated optimisation method for controlled dynamic mechanical systems

It is difficult to consider the interaction among mechanical parts, mechanical system and control system when carrying out design optimisation of mechatronic products which are usually controlled dynamic mechanical systems. A cosimulation based integrated optimisation method, which achieve topology optimisation of mechanical parts, mechanical system optimisation and controller parameter optimisation in one optimisation process, is presented. The proposed optimisation process considers the interaction among mechanical parts, the mechanical system and the control system within a controlled dynamic mechanical product. The principles of the optimisation process and a software framework are given. Different discipline software tools can run automatically in the presented framework. With the integrated optimisation process, the mechanical properties of the parts, the dynamics performance of the mechanical system and the overall dynamic properties of the mechatronic product can simultaneously achieve the optimum. The effectiveness is verified by a controlled crank-connecting rod mechanism with a flexible connecting rod.

The working pressure research of piston pump RN-3.8

The research of working pressure of one-piston pump with a combined compensator of pressure pulsations during the operating cycle is carried out. One of the basic gas law in an isothermal process, namely the law of Boyle-Marriott is employed. The law of piston motion which is driven from the crank-connecting rod mechanism (the axis of the crank shaft is made offset downwards relative to the axis of the piston to reduce the magnitude of lateral forces) is used. The piston drive crank rotation angle, the primary pressure in the compensator are taken into account. The research is needed to ensure a stable high-pressure feed of medium (solution) pumped by the pump, with a reduced level of pulsation. The quantitative dependences of the solution volume in the compensator on the piston movement, the solution feed pressure relative to the crank shaft rotation angle, the minimum required amount of total given volume of combined compensator air (it is 0.02m 3 ) are defined. Practical significance of the obtained results of the research is to develop a piston pump design. It provides a stable feed pressure, moderate pulsation level of the solution, which is pumped.

A Flexible Electronic Helical Guide Controller

In this paper, an Electronic Helical Guide Controller (EHGC) is proposed, for helical gear shaping processes. In most traditional gear shaper machines, the cutter's reciprocating movement is driven by a crank-connecting rod mechanism. Therefore, this study adopts this kind of gear shaper as the machine platform to establish an accurate mathematical model. The control algorithm is embedded in the interpolation module of the CNC system using electronic gearbox techniques to realize special multi-axis linkage control requirements. The crankshaft's angular position is measured and the rotational speed is calculated in each control cycle. The actual position and velocity of the cutter along the Z-axis can be calculated using the geometric relations of the crank-connecting mechanism, and motion in the other axes can be controlled by the electronic gearbox. A special G code with parameters (G83) is also designed and the EHGC control through NC programming is realized in an improvised gear shaping CNC machine. The proposed EHGC is low cost and easy to implement in practice since it does not need a linear grating ruler and a probe on the Z-axis. Furthermore, EHGC allows the flexibility to change a part's helix angle to compensate for distortions caused by heat treatment. Simulations and experiments are performed to verify the effectiveness of the proposed EHGC.