Piston Pin Bearings Research Articles

Öltransport und Reibungsbewertung innerhalb der Kolbenbolzenlagerung

Increased loads and lower oil supply of today’s low-consumption internal combustion engines lead to higher demands on mechanical and elastohydro-dynamical design methods of the piston pin bearing. The bearing is not lubricated directly but through spray oil or oil mist. A description of the lubrication mechanism within the bearing has mostly been researched theoretically. In order to understand the friction conditions and lubrication mechanisms, the bearing is tested on an external test bench with high loads and a hydrostatic bearing of the piston. An enginelike lubrication can be variably adjusted. By comparing the contact pattern between measurement and calculation, conclusions can be drawn about the behaviour of the lubricant within the bearing. Using computational fluid dynamic calculations (CFD) the amount of oil in the gap of different lubrication directions is regarded. After transferring the results to the test bench a directed transport of lubricant is determined. Final friction measurements with an adapted direction of lubrication show a good accordance to the calculation results. These results validate a multi body system calculation (MBS/MKS) with a lubricating film coupling.

On the tribo-dynamic interactions between piston skirt-liner system and pin assembly in a gasoline engine

Piston Skirt-Liner (PSL) system and Piston Pin Bearing (PPB), two key friction pairs in piston-assembly, interact with each other via impact and friction when transmitting the combustion load to crank train. Literature reporting such an interaction behavior in terms of tribology and dynamics is still rare, due to the complexity in a systematic modeling way. This paper proposed an efficient numerical model that fully couples these two friction pairs to investigate tribo-dynamic interactions between them. The model is built by coupling Reynolds-based mixed lubrication models for the friction pairs with Lagrange multibody motion equations for the piston-connecting rod-crank mechanism. Coupling effects between the piston skirt-liner system and the pin assembly are explored by comparing the cases contain the two friction pairs and one of them. Based on the above analyses, some design parameters including pin assembly clearance and pin offset, are further studied to disclose their influences on the tribo-dynamic performance of these two friction pairs. This work has a guiding significance for the systematic design of piston-assembly aiming to improve the dynamic property, economical efficiency and environmental-friendliness of engines.

Experimental analysis of the system behavior of a two-stage variable compression ratio (VCR) system in fired SI-engine operation

Especially for turbocharged SI engines, systems that allow to adapt the geometrical compression ratio offer advantages in terms of part load efficiency and maximum power output. In this study a conrod based two-stage VCR system with an eccentric piston pin bearing is investigated in fired engine operation by means of a specially designed measurement technique. For this purpose different sensor technologies were equipped to a VCR conrod and the oil supply system of a prototype crankshaft. The data transmission was realized by an optimized mechanical linkage system and a digital rotation telemetry system. The high-performance measurement technique presented in this paper enables a detailed analysis of the influencing parameters resulting from the fired engine operation, such as dynamic pressure stimulation in the crankshaft oil supply or the acceleration of the internal oil columns. The presented crank angle based measurement results of the system are obtained through fired testbench investigations on a three-cylinder full engine in the entire engine map, focusing on the speed range up to [Formula: see text] and loads up to [Formula: see text]. A detailed analysis of the conrod system behavior in high and low compression ratio is shown. A key finding is, that the so called “hydraulic pretension” of the support chamber is necessary to meet the requirements for a stiff force transmission in the low compression ratio stage. The in-depth investigation contributes to the build up of a comprehensive system understanding and represents a solid base to expand the development process of conrod based two-stage VCR systems.

Vibrations of a Piston Pin with Eccentric Center of Gravity

Combustion pressure boost in the cylinder of modern diesel engines increases the loads acting on the piston pin bearings and lubrication of the piston pin bearings becomes a serious problem. Using a piston pin with an eccentric center of gravity solves this problem. This article deals with the phenomenon of parametric resonant oscillations of the piston pin during the reciprocating motion of the piston. The purpose of the study is to use a phenomenon that increases the amplitude of the oscillations and, consequently, the sliding speed in the relative rotational movement of the piston pin.

Optimization of the parameters of the piston pin bearing of the tractor engine taking into account the solution of the lubrication problem

The task of the investigation is to make the model, the algorithm, the program and the results of the calculations of optimization of the parameters of the bearing sliding of piston pin of the internal-combustion engine. An approximate mathematical model of dynamically loaded bearings of a piston pin of the internal-combustion engine was built up with the account of calculation methods of the statically loaded sliding bearings. The approximate mathematical model describes the relationship of output parameters of bearings of piston pin the operational and structural factors. The model is based on the method of M.V..Korovchinskiy of hydrodynamic calculation of statically loaded sliding bearings. The solution of optimization task was performed with the help of the author’s program in MATLAB environment. The optimization was produced by using the gradient release method. At each iteration a step was calculated in the condition of minimum of the function of the independent variable. The program of the calculation is a finished product and it can be used at the designing of the bearings of sliding engines.

An Investigation on the Pin Bearings’ Optimization of a Hermetic Reciprocating Compressor

A hermetic reciprocating compressor is the most energy consuming component of the refrigerators. Therefore performance improvement studies of the compressor play an important role to reduce overall energy consumption of the refrigerators. Design of bearings is one of the major study areas influencing reciprocating compressor performance.In this study crank pin and piston pin bearings in hermetic compressor applications are investigated and optimized. The effect of operating conditions, bearing offset between crank pin and piston pin, bearing clearance and bearing location along the shaft on the friction loss were investigated and optimal bearing designs were developed.Efficiency measurements of the compressor showed that the improved crank pin and piston pin bearing designs provide up to 3.8% increase in the COP as a result of reduction in mechanical loss that is significantly influenced by the length of the bearings, bearing location along the shaft and operating conditions.

Friction Power Loss Simulation of Internal Combustion Engines Considering Mixed Lubricated Radial Slider, Axial Slider and Piston to Liner Contacts

Different types of mixed lubricated contacts are present in internal combustion engines. These are several radial slider bearings; for instance, in main bearings; big end, small end, and piston pin bearings; as well as axial slider bearings and piston–liner contacts. Phenomena such as friction power loss and wear as well as acoustic excitation and oil consumption of the overall lubrication system are mainly affected by these contacts. Therefore, the simulation-based investigation of oil film–lubricated contacts is important during the development process of internal combustion engines. Due to the highly nonlinear interactions, the applied mathematical models have to consider the dynamics of the overall flexible body system in addition to the detailed properties of the contacts and the lubricant itself. This work outlines both the theory of the separated mathematical models and their coupling. The large number of nonlinear contacts, which is possible to consider when applying the presented coupling approach, is emphasized. Furthermore, application of a friction power loss analysis for an in-line four-cylinder internal combustion engine is described.

S114021 エンジン軸受のピストンピンオフセットを考慮した全軸受連成解析([S114-02]トライボロジーの基礎と応用(2))

A Simiultanous analysis for piston pin bearing, connecting rod small end bearing, connecting rod large end bearing and main bearing of engine bearings is establised, by considering piston pin offset, i.e. eccentricity of center lines between pinton pin bearing bush and piston.

The Analysis of Lubrication for HPD Diesel Engine Piston Pin Bearing

Based on the unified Reynolds equation model and fast Fourier transform (FFT) method, the lubrication performance of the piston pin bearing for high power density diesel engine was studied by numerical simulation. First of all, through the coupled solving of a unified Reynolds equation and elastic deformation equation, the orbit of journal center for piston pin bearing is investigated. The eccentricity ratio of the piston pin bearing in vertical direction of the piston stroke is smaller, however it is much larger in the downward direction of the piston stroke, which indicate that the below area of the piston pin bearing bears greater load and occurs larger deformation. This is consistent with the reality that the below area of the piston pin bearing is prone to damage and wear. Secondly, the influence of the different bearing clearances and width on the minimum oil film thickness is discussed, The results show that the minimum oil film thickness is increased, while the width of piston pin bearing is increased or the clearance of piston pin bearing is decreased.

The Analysis of the Deformation and Contact Lubrication Problem of HPD Diesel Engine Piston Pin Bearing Based on the FFT Method

Based on the unified Reynolds equation model and fast Fourier transform (FFT) method, the lubrication performance of the piston pin bearing for high power density diesel engine was studied by numerical simulation. First of all, through the coupled solving of a unified Reynolds equation and elastic deformation equation, the influence of the viscous-pressure effect on the maximum film pressure and the minimum oil film thickness for piston pin bearing are investigated. The results show that, after considering the viscosity-pressure effect, the minimum oil film thickness and the maximum film pressure of semi-floating piston pin bearings for high power density increase, and the elastic deformation decreases in greatest load position. It confirms that the bearing capability is greatly enhanced while the viscosity- pressure effect is considered. Secondly, The eccentricity ratio of the piston pin bearing in vertical direction of the piston stroke is smaller, however it is much larger in the downward direction of the piston stroke, which indicate that the below area of the piston pin bearing bears greater load and occurs larger deformation. This is consistent with the reality that the below area of the piston pin bearing is prone to damage and wear

G070062 エンジン軸受の簡便解法([G07006]エンジンシステム部門一般セッション(6):燃料と潤滑)

In Engine, four types of journal sliding bearings of piston pin bearings(consist of one connecting rod small end bearing and two piston pin boss bearings), connection rod big end bearing and main bearing are used and these bearings are influenced each other. By comparing a simultaneous analysis and approximate analyses proposed by authors for engine bearings, practical approximate analyses are established and the considerations of balance weight are clarified. To save computation time for engine bearing analysis by finite width bearing theory, variable step's Runge-Kutta methods with inherent algorithm of engine bearings are examined. In this paper, as an another method to save computation times, easy methods with iteration are introduced. As the iteration methods, evaluation method at edge step and evaluation method at middle step are proposed. By comparing computation time, it is clarified that the time by evaluation method at middle step become less.

G070063 エンジン軸受の流体潤滑トライボロジー理論の研究([G07006]エンジンシステム部門一般セッション(6):燃料と潤滑)

By comparing a simultaneous analysis and approximate analyses proposed by author for four types of engine bearings of piston pin bearings(consist of one connecting rod small end bearing and two piston pin boss bearings), connection rod big end bearing and main bearing ,these analyses are clarified. It is nessecary for finite width bearing theory for paractial bearing design and practiocal phenomena analysis to save computation time, variable step's Runge-Kutta methods and iteration easy method with inherent algorithm of engine bearings are examined.

Piston pin in mixed friction contact

Within the framework of the research project No. 868 of the FVV research association Verbrennungskraft maschinen e. V. (Combustion Vehicles Reg.) a user-friendly numerically stable simulation tool was developed by Stuttgart University and Kassel University. The tool was validated by experiments, and offers designers and developers the possibility of system analysis and optimization of piston pin bearings. Non-linear elasto-hydrodynamic processes were included at the same time in the dynamically loaded bearing contacts of piston/piston pin and piston pin/connecting rod, with the reciprocal effects.

エンジン軸受の連成解析と簡略解析 : コンロッド大端部軸受とピストンピン軸受(エンジンのトライボロジー・潤滑油,エンジンのトライボロジー・潤滑油)

エンジン軸受の連成解析と簡略解析 : コンロッド大端部軸受とピストンピン軸受(エンジンのトライボロジー・潤滑油,エンジンのトライボロジー・潤滑油)

偏心軸を有するクロスヘッドピン軸受の負荷能力について

This paper refers to a new investigation to improve the load carrying capacity of the crossheadpin bearing in a 2-stroke cycle diesel engine. By using a specially equipped journal with a pair of eccentric sections the oscillating bearing can be forced to move up and down just like a piston-pin bearing in a 4-stroke cycle engine. Such a squeeze motion of the oil-film between a journal and a bearing has an ability to increase the oil-film thickness. Then, from the theoretical analyses on effects of various bearing shapes the following features and optimums for design became evident.(1) According to the change of an oscillating direction each sliding face is alternatively unloaded and the oil-pumping ability is generated.(2) In order to keep the oil-film pressure lower than the elastic flow pressure of a bearing metal and make the oil-film thickness as large as possible the next designing points are needed.(i) The ratio of a radial clearance to the radius is about 5 × 10-4 .(ii) The eccentricity between journals is as large as the radial clearance.(iii) The width ratio of a main journal to the whole bearing is about 0.7.

AN ANALYSIS OF PARTIAL ARC BEARINGS INCLUDING EFFECTS OF ELASTICITY AND VISCOSITY

AbstractThe aim of this investigation is to analyze the performance of a sleeve bearing which is subjected to loads such as those imposed on the piston pin bearing of a two‐stroke cycle diesel engine. This bearing is the most highly loaded of all bearings in the engine, and its performance is critical to satisfactory operation of the engine. To date, there has been no theoretical work published which satisfactorily explains its operation and, as a result, the design of the bearing has been by cut and try methods.In this report, the operation of this type of bearing is examined, using the theories of elasto‐hydrodynamic lubrication. The resulting calculations of bearing performance show that loads far greater than those calculated by means of the hydrodynamic equations can be supported with equal oil film thickness. Further work is required to optimize the design of these bearings and to correlate the cut and try designs presently in use.To assist the reader in the understanding of the Nomenclature and Subscripts used by the author, they are defined in the APPENDIX following the REFERENCES.

Temperature Measurements of the Connecting Rod, Piston Pin and Crankpin Bearing of an Automobile Gasoline Engine

The thermocouple wires were led from the connecting rod to the piston through in a coil which received a twisting stress only in the piston pin. From here the wires were led out by means of thecombustion chamber pass through and on the circular springmethod that had been used by the authors. From the measuring results, the followings were found. (i) The heat flow from the piston reaches to the middle part of the connecting rod, at the big end, however, this effect fade away. The temperatures of the crankpin and main bearing metal rise a certain extent above the surroundings by the friction. (ii) These temperatures are increased proportionately with the engine speed. (iii) An increasing the oil temperature increases the temperatures of the bearing-metals as same extent as it.