Piston-crank Mechanism Research Articles

Conformal coating of powders by magnetron sputtering

Applying a thin film coating to powder under vacuum conditions requires mechanical agitation of the powder to achieve a uniform coating on the surfaces of the powder particles. In this work, we develop a piston-crank mechanism for agitating powder, using mathematic descriptions of system behavior (dynamics, forces, and stresses) as well as operational experience to improve the design. The viability of the system is demonstrated by applying tungsten onto spherical copper powder to produce uniform, conformal coatings. The capability of the agitation system is compared to coatings produced using alternative agitation methods, revealing that the piston-crank mechanism produces a larger coating volume per energy input than these other techniques.

PRIMENA EPICIKLIČNIH ZUPČASTIH PRENOSNIKA SA NEOKRUGLIM ZUPČANICIMA ZA POVEĆANJE STEPENA KORISNOSTI SUS MOTORA

Povećanje efikasnosti SUS motora je tema mnogih diskusija u struci, i jedan pristup koji se sreće je modifikacija termodinamičkog radnog ciklusa motora kojom se realni cilkus približava idealnom. Ovaj rad pokušava to da postigne izmenom kinematike klipnog mehanizma uvođenjem epicikličnih neokruglih zupčanika između kolenastog vratila i zamajca. Dodatak neokruglih zupčanika menja radni ciklus uvođenjem prisilnog perioda mirovanja klipa tokom ključnih momenata tokom ciklusa. Moguća rešenja oblika zupčanika izračunata su na osnovu prenosnog odnosa izraženog poznatom periodičnom funkcijom. Konačni rezultat je epiciklični prenosnik sa neokruglim zupčanicima sa primetnim uticajem na kinematiku klipnog mehanizma, što za posledicu ima povećanje efikasnosti motora.

Piston crank mechanism simulation using finite element method

In this paper we present the analysis of the piston crank mechanism, using the finite element method using mechanical event simulation (MES). Mechanical event simulation is a modern process of modeling and analysis of mechanical systems, much different from the classical methods known in mechanical engineering. The use of MES involves a combination of kinematics of mechanical systems, dynamics of rigid bodies, respectively nonlinear stress analysis. So, mechanical event simulation is engineering by simulating a physical event in a virtual laboratory. The crank-piston mechanism analysis has been achieved with the Simulation Mechanical program, which aimed to determine the stress state, nodal displacement or relative elongations (strains) of mechanism elements, at different time steps of the kinematic cycle, depending on the kinematic and kinetostatic parameters variable according to different curves.

Research and development of new variable compression ratio (VCR) engine mechanism (2nd Report, Dynamics analysis and vibration experiment of VCR engine mechanism)

In order to improve the efficiency of combustion engines, variable compression ratio (VCR) engine is researched. VCR engine changes the compression ratio according to its mechanical configuration. One of the solutions to construct VCR engine is the multi-link type. Multi-link type has an advantage for reducing high order shaking force which is the source of mechanical vibration. Since piston motion strongly influences shaking force, it is required to make the piston displacement profile close to sine curve. However, conventional combustion engine is designed based on four-link piston crank mechanism. Because of the design constraint due to four-design parameters regarding the four-link piston crank mechanism, piston displacement profile diverges from sine curve. In order to solve this problem, six-link piston crank mechanism is applied to VCR engine. Since six-link piston crank mechanism has six-design parameters, the piston displacement profile becomes closer to sine curve than that of the four-link piston crank mechanism. A Stephenson type six-link piston crank mechanism whose constitute four-bar mechanism is the double-crank mechanism is newly designed. And, this mechanism is applied to VCR engine model. We want to put this VCR engine model to practical use. We show basic characteristic of mechanical vibration. First, we measure frame displacement of VCR engine model when the compression ratio vary high compression ratio. Next, we compare frame displacement of VCR engine model with frame displacement of four-link engine model. As a result, tendency of basic characteristic of mechanical vibration almost equate to tendency of dynamics analysis.

Generating renewable power from water hammer pressure surges

Since the 18th century, hydraulic ram pumps have harnessed the water hammer effect to move water in a renewable and sustainable manner. This article demonstrates that, by substituting the pressurised water delivery system for an energy conversion mechanism, the operating principles behind hydraulic rams can also be adopted for the purposes of providing renewable energy. An experimental study involving a small scale model device driving a piston-crank mechanism is presented to demonstrate the concept. The peak mechanical efficiency of the test rig was found to be 25.7%, with the time-averaged efficiency varying from 0.3 to 1.7%.

A new closed-form method for inertia force and moment calculation in reciprocating piston engine design

The piston crank mechanism is an important component of a reciprocating piston engine. It is an inherent vibration system, and as such, the calculation of unbalance quantity is a critical procedure in balancing mechanism design, which is adopted to balance inertia loading. The traditional method usually applies a Taylor series expansion with the crank-conrod ratio, then a Fourier transform with the crank angle. The Taylor expansion generally ignores the influence on calculations resulting from the high order terms. However, the high order terms of the Taylor expansion will also contribute to the low order terms in the Fourier series. This will induce poor precision in the inertia loading calculation, especially in a high crank-conrod ratio engine. Thus, this paper proposes a new closed-form method, which only adopts a Fourier transformation for the calculation. The coefficients of the Fourier transformation terms contain the contributions of all order terms of the crank-conrod ratio. Therefore, we named it as a closed-form method. Compared with the traditional method, the closed-form method improves the numerical accuracy of the secondary reciprocating inertia force by 1.5%–4%, when the crank-conrod ratio varies from 0.25 to 0.4. Using this new closed-form method to design a balancing mechanism, the primary and secondary reciprocating inertia forces can be completely balanced. For an engine, where the primary and secondary inertia forces are balanced, the ratio of the residual inertia force to the total inertia force using the traditional method is 1.5%, while the ratio decreases to 0.5% using the closed-form method. The closed-form method is independent of engine configurations, including centric and eccentric engines, and single and multi-cylinder engines. Examples of applications using the proposed method are provided.

Vibration Analysis of the Engine Using Biofuel Blends: A Review

The vibrations and noise of the internal combustion engine may be affected by several factors such as combustion pressure, movement of the piston-crank mechanism, coolant factor flow, engine body, and fuel inlet of the injector. Various ways have been done to reduce vibration and noise in the engine, including fuel. Alternative biofuels can be used in internal combustion engines without having to modify and change parameters on the machine. Several researchers have studied the effects of vibration and noise in the engine using various fuel mixtures. The results from some literature reported that biodiesel blend fuels proved to reduce vibration and noise in engines as compared to pure diesel. Meanwhile, ethanol fuel mixed with gasoline shows significant vibration changes at engine speeds of 1,500 and 2,500 rpm. The review aims to analyse the effects of vibration and noise on engines fueled by fuel mixtures, as well as fuel properties used as a move for future research. Based on the analysis from several kinds of literature, it shows that the use of biodiesel fuel and ethanol-gasoline can reduce vibration and noise.

The issues of designing of construction features of the internal combustion cam engine

On the pages of the article described cam-piston mechanism developed as an alternative to piston crank mechanism. The main feature of this mechanism is that the piston is dwell in the TDC by the 30°CA and thus allows combustion of the fuel in constant volume. Authors presented the process of designing an analytical cam. The starting point for the calculation was the displacement of piston graph and the limits of acceleration and velocity values obtained. The results of strength calculations of the cam with regard to fatigue problems are also presented. Calculations were carried out in order to reduce the weight of the cam. For this purpose, the Finite Element Method was used.

Shape optimization for a link mechanism

This paper presents a numerical solution for shape optimization problems for link mechanisms, such as a piston-crank mechanism. The dynamic behavior of a link mechanism is described by a differential-algebraic equation (DAE) system consisting of motion equations for each single body and constraints of linkages and rigid motions. In a shape optimization problem, the objective function to maximize is constructed from the external work done by a given external force, which agrees with the kinetic energy of the link mechanism, for an assigned time interval, and the total volume of all the links forms the constraint function. The Frechet derivatives of these cost functions with respect to the domain variation, which we call the shape derivatives of these cost functions, are evaluated theoretically. A scheme to solve the shape optimization problem is presented using the H 1 gradient method (the traction method) proposed by the authors as a reshaping algorithm, since it retains the smoothness of the boundary. A numerical example shows that reasonable shapes for each link such that mobility of the link mechanism is improved are obtained by this approach.

Evaluation of variable mass moment of inertia of the piston–crank mechanism of an internal combustion engine

The current paper presents an original method for evaluating the variable mass moment of inertia of the piston–crank mechanism of an internal combustion engine based on the principle of kinetic energy equality of the real mechanism and its reduced model. The method has been developed to evaluate the variable mass moment of inertia of a 12-cylinder V-engine having a piston–crank mechanism with main and auxiliary connecting rods. In order to study the influence of the piston–crank mechanism configuration on mass moment of inertia variability, the procedure has been also applied on virtual ‘shortened’ variants: 2-cylinder and 6-cylinder V-engines with main and auxiliary connecting rods, and a 6-cylinder in-line engine with simple piston–crank mechanism. The results are compared with values obtained using the usual simple method for determining the approximate constant mass moment of inertia based on Huygens–Steiner theorem. It is shown that there is negligible difference between the constant value obtained by the simple method and the mean value of variable mass moment of inertia evaluated using the proposed model. Variability of mass moment of inertia is relatively small for a large number of cylinders, but it rises with cylinder number reduction. The presented method with appropriate modifications may be applied to any piston–crank mechanism arrangement.

A dual-fuel compression ignition engine – distinctive features

For many years in the Department of Automobiles and Internal Combustion Engines in Technical University of Radom there are carried out investigations on dual-fuel compression ignition engine in which the ignition is initiated by a pilot diesel oil dose and the applied main fuels have properties similar to those applied in spark ignition engines. The tested fuels were methanol, ethanol, LPG and natural gas. Analysis of the obtained results allowed to make some generalizations and to determine advantages as well as problems which should be solved for higher efficiency, power and durability. The paper will present information on efficiency, power, toxic exhaust emission and chosen parameters of combustion process of a dual-fuel compression ignition engine as well as on a difficult to control – knock combustion which may result in lower engine durability and piston crank mechanism failure.

High Compression Ratio High Efficiency Gasoline Engine with Variable Speed Piston-crank Mechanism

In order to avoid knocking phenomena and also to reduce the cooling loss, the authors have studied a new piston-crank mechanism with various specifications. At first, numerical simulations to predict thermal efficiency and knocking limit were performed using 0-D model to confirm the idea. As a result, high compression ratio operation was found possible with a short combustion period. Next, a model engine was designed and built to evaluate the predicted result. A couple of leaf-shaped gears to move piston faster than usual engine near TDC was chosen to achieve higher thermal efficiency. Experimental results showed that higher indicated and brake thermal efficiency can be obtained and that lower exhaust gas emissions also can be obtained.

H26 小型漁船用機関のピストン-クランク機構における異常時の動特性解析(H2 機械力学(振動制御))

H26 小型漁船用機関のピストン-クランク機構における異常時の動特性解析(H2 機械力学(振動制御))

107 小型漁船用機関のピストン-クランク機構における異常時の動特性解析(セッション2 評価・診断II)

107 小型漁船用機関のピストン-クランク機構における異常時の動特性解析(セッション2 評価・診断II)

4715 変速ピストン-クランク機構による熱効率の改善(S56-3 エンジン燃焼-さらなる進化を目指して-(3),S56 エンジン燃焼-さらなる進化を目指して-)

A new combustion method of high compression ratio SI engine was studied and proposed in order to achieve higher thermal efficiency of SI engine. A variable speed piston-crank mechanism was adopted which allowed the piston to move rapidly near TDC. As a result, this concept can be operated at the compression ratio of 14 using regular gasoline. A new single cylinder engine was designed and built for proving its performance. The experimental results show that a knocking limit has improved and better indicated thermal efficiency has been obtained under engine speed upto 3000r/min using an eccentric cam mechanism.

Particle Resistance in Pulsation Flow

The resistance coefficient of a particle was measured in a pumped flow with added pulsation from a piston crank mechanism. As a result of experiment, it was found that the resistance coefficient of the particle was increased by a remarkable 7Hz and was for the increased by 15Hz when the pulsation frequency of the pumping fluid was 0-25Hz. Under these conditions, the increasing amplitude of the flow rate fluctuation of the pumping fluid appeared experimentally.

Resonant Amplitudes of Pressure Pulsation in Pipelines : 2nd Report, A Calculation by Method of Transfer Matrix

A method is proposed to calculate the resonant amplitudes of pressure pulsation in pipelines by using transfer matrices in which equivalently linearized damping forces are employed. The resonant curves for several pipelines with an orifice, a tank or a branching are calculated. The results show good agreement with the experimental values. The pressure amplitudes for the 2nd harmonic component which arise from the piston-crank mechanism are calculated and are superposed on ones for the fundamental component. The results also show good agreement with the experimental values.

On the Vibration of a Power-Transmission System Having Angular Clearances, Part 3 : Experiment of a Two-Mass One-Stiffness System Retarded by Collision Damping as well as Velocity-Proportional Damping

To examine the approximation of collision damping in the former report, Part 2, here a two-mass one-stiffness system is checked experimentally, and as a result the author verifies that the theory gives practically sufficient accuracy of the order of 1st approximation. The experimental system is made up of an electrical dynamometer, an intermediate shaft, a variable clearance joint, and a fan, excited by a piston crank mechanism. The author reads the torque and r. p. m. at the maximum amplitude state, besides detecting electrically from the revolving system its fluctuating torque, collision velocity and touching of clearance parts.

On the Vibration of a Power-Transmission System Having Angular Clearances (4) : Analysis and experiment of a two-mass one-stiffness system retarded by collision damping as well as velocity-proportional damping

To examine experimentally the approximation of collision damping in the former report, here a two-mass one-stiffness system is approximately analysed as to its maximum amplitude state, experimentally checked, and as a result the author verifies that the theory gives practically sufficient accuracy of the order of 1st approximation. Then the estimation of collision velocity may be given practically as well as frequency and amplitude at the maximum amplitude state. if the data of the system dimensions and velocity-proportional damping coefficient are given. The estimated collision velocity may be an useful key of the problem about the failure of clearance parts. The experimental system is made up of an electrical dynamometer, an intermediate shaft, a variable clearance joint, and a fan, excited by a piston-crank mechanism. The author reads the torque and rpm at the maximum amplitude state, besides detecting electrically from the revolving system its fluctuating torque, collision velocity and touching of clearance parts.