Internal Combustion Engine Piston Research Articles

Influence of Intake/Exhaust Channel Lateral Profiling on Thermomechanics of Pulsating Flows

The hypothesis that pipeline lateral profiling can be used to regulate pulsating flows in the air-gas systems of energy machines is tested. The results of the physical simulation of gas dynamics and local heat transfer in the intake and exhaust channels of various configurations in the piston internal combustion engine in the conditions of gas-dynamic nonstationarity are presented. We have established that the lateral profiling of intake and exhaust pipes promotes the stabilization of gas flows in the air-gas systems of the engine, and decreases the intensity of the local heat transfer by up to 30%, depending on the initial conditions.

Numerical analysis on effect of surface asperity of piston skirt on lubrication performance

Tooling marks usually remain as grooves on the surface of piston of internal combustion engine, due to the final finishing process by machining. In this paper, therefore, the influence of the grooves fabricated by machining process on the surface of the piston skirt on the lubrication performance was elucidated by applying the Taguchi method. The effect of shape and alignment of the grooves on the oil film thickness and the friction coefficient was calculated using Elastic Hydrodynamic Lubrication theory. From results, it was suggested the control of the groove shape in the width direction may be useful for reducing the friction coefficient.

The use of thermography in the diagnosis of ship piston internal combustion engines

The intensity of infrared radiation emitted by objects depends mainly on their temperature. One of the diagnostic signals may be the temperature field. In infrared thermography, this quantity is used as an indicator of the technical condition of marine objects. The article presents an overview of the use of infrared thermography for the diagnosis mainly of marine piston floating objects and various types of reciprocating internal combustion engines as well as examples of own research results. A general introduction to infrared thermography and common procedures for temperature measurement and non-destructive testing are presented. Experimental research was carried out both in laboratory conditions and in the operating conditions of sea-going vessels. Experimental studies consisted of the presentation of photographs of the same objects made in visible light and the use of infrared thermography. The same objects were also compared, but for different cylinders of the tested internal combustion engines as well as for the up state and fault state. The characteristics of the temperature values at selected points were taken depending on the engine load along with the approximation mathematical models of these dependencies.

Selected Tribological Properties of A390.0 Alloy

AbstractEmergence of new designs for internal combustion engines resulted in a necessity to search for new materials which will rise to excessive technological requirements under operating conditions of modern internal combustion engines of up to 150 kW. Focusing only on material properties, theoretically existing alloys should meet presents requirements. More importantly, existing materials are well fitted to the entire crank-piston system. Thus, there is a need for a more thorough examination of these materials. The paper presents studies on determination of coefficient of friction μ and wear for the A390.0 alloy modified with AlTi5B master alloy combined with EN GJL-350 cast iron. The characteristics of a T-11 tribological tester (pin on disc) used for the tests, as well as the methodology of the tribological tests, were described. Also, the analysis of the surface distribution of elements for the pin and the disc was presented. The studies were realized in order to find whether the analyzed alloy meets the excessive requirements for the materials intended for pistons of modern internal combustion engines. The results show that the A390.0 alloy can only be applied to a load of 1.4 MPa. Above this value was observed destructive wear, which results in the inability to use it in modern internal combustion engines.

A torsional vibration damper based on a serial viscoelastic coupling of its seismic mass

The design of dynamic torsional vibration dampers of piston internal combustion engines is generally based on the principle of a dynamic damper with one degree of freedom in which the coupling of the seismic mass of the damper to the basic dynamic system is realized by a two-parameter parallel rheological model. With known realizations of this principle, it is usually difficult to achieve the optimum value of the respective damper parameters determined from the computational models, which is particularly true for optimal damping values. A dynamic torsional damper, based on the series arrangement principle of the elastic and damping element, offers better design options to achieve the optimum parameters of both the elastic and damping elements.

Method for Determining Volumetric Efficiency and Its Experimental Validation

Abstract Modern means of transport are basically powered by piston internal combustion engines. Increasingly rigorous demands are placed on IC engines in order to minimise the detrimental impact they have on the natural environment. That stimulates the development of research on piston internal combustion engines. The research involves experimental and theoretical investigations carried out using computer technologies. While being filled, the cylinder is considered to be an open thermodynamic system, in which non-stationary processes occur. To make calculations of thermodynamic parameters of the engine operating cycle, based on the comparison of cycles, it is necessary to know the mean constant value of cylinder pressure throughout this process. Because of the character of in-cylinder pressure pattern and difficulties in pressure experimental determination, in the present paper, a novel method for the determination of this quantity was presented. In the new approach, the iteration method was used. In the method developed for determining the volumetric efficiency, the following equations were employed: the law of conservation of the amount of substance, the first law of thermodynamics for open system, dependences for changes in the cylinder volume vs. the crankshaft rotation angle, and the state equation. The results of calculations performed with this method were validated by means of experimental investigations carried out for a selected engine at the engine test bench. A satisfactory congruence of computational and experimental results as regards determining the volumetric efficiency was obtained. The method for determining the volumetric efficiency presented in the paper can be used to investigate the processes taking place in the cylinder of an IC engine.

Operational Degradation of Spheroidal Graphite Cast Iron EN GJS SiMo

The specifics of low-alloyed cast irons after EN 16124 standard of type GJS SiMo for high temperature applications of exhaust tracts of internal combustion piston engines. Boundary exposition temperature. Structure failure of cast iron by temperature overloading. Metalography, SEM, XRD of overexposed exhaust pipelines. Failure reason hypothesis of useful properties by exceeding of critical temperature.

Improvement of the thermal and mechanical flow characteristics in the exhaust system of piston engine through the use of ejection effect

The results of experimental research of gas dynamics and heat transfer in the exhaust process in piston internal combustion engines are presented. Studies were conducted on full-scale models of piston engine in the conditions of unsteady gas-dynamic (pulsating flows). Dependences of the instantaneous flow speed and the local heat transfer coefficient from the crankshaft rotation angle in the exhaust pipe are presented in the article. Also, the flow characteristics of the exhaust gases through the exhaust systems of various configurations are analyzed. It is shown that installation of the ejector in the exhaust system lead to a stabilization of the flow and allows to improve cleaning of the cylinder from exhaust gases and to optimize the thermal state of the exhaust pipes. Experimental studies were complemented by numerical simulation of the working process of the DM-21 diesel engine (production of “Ural diesel-motor plant”). The object of modeling was the eight-cylinder diesel with turbocharger. The simulation was performed taking into account the processes nonstationarity in the intake and exhaust pipes for the various configurations of exhaust systems (with and without ejector). Numerical simulation of the working process of diesel was performed in ACTUS software (ABB Turbo Systems). The simulation results confirmed the stabilization of the flow due to the use of the ejection effect in the exhaust system of a diesel engine. The use of ejection in the exhaust system of the DM-21 diesel leads to improvement of cleaning cylinders up to 10 %, reduces the specific fuel consumption on average by 1 %.

Impact of Contaminants in Motor Oil on the Wear of Aluminum Parts of the Internal Combustion Engine

The design of internal combustion engine use plain bearings, pistons and piston-rod which are based on aluminium, brass. Further are used steels with coating based on aluminium and bronze. The paper describes the impact of contaminants in motor oil on wear of materials, which are used in production of parts of internal combustion engine. Reichert tester M2 for evaluation the lubricity from Petrotest Company was used in order to assess ability of motor oils to create proper lubricating film. Reichert tester M2 belongs to a group of equipment simulating real frictional contact. Wear particles come into oil in lubrication system, where they cause contamination and degradation of lubricating properties and consequently it may result in major failure of machines. Among these contaminants are included mainly water, fuel, water coolant, adhesive, abrasive and fatigue particles wear. The aim of research was focused only on oil contaminated with fuel including petrol, diesel and biobutanol.

THE EFFECT OF SELECTIONS IN THE ZONE OF THE EDGE OF THE PISTON COMBUSTION CHAMBER ON ITS HEAT TENSION AND STRENGTH RESOURCES

The analysis of the main typical damages of pistons of internal combustion engines, the subsequent refusals and the reasons of their defiant have been given. It is shown that for today cases of violation of the concept of the guaranteed providing a resource of the piston at a stage of its design take place. Options of forming of edges of combustion tubes of pistons of the diesel 4ChN12/14 are considered. In relation to operating conditions of automobile and tractor diesels borders of resource durability of alternative options of edges of combustion tubes are evaluated.

The gas-dynamic unsteadiness effects on heat transfer in the intake and exhaust systems of piston internal combustion engines

This article presents the results of experimental research into the gas-dynamic and heat-exchange parameters of gas flows in the intake and exhaust pipelines of piston ICEs (internal combustion engine) taking into account the nonstationary nature of the gas exchange processes. Some characteristic times of transient processes (recovery time and relaxation time) are established during the gas flow recovery in round pipelines. Based on the obtained data, the degree of non-stationarity or unsteadiness of the gas-dynamic processes in piston ICE pipelines can be established. It is demonstrated that there are two types of resolution for gas-dynamic unsteadiness. It is established that unsteadiness reduces the instantaneous local heat transfer intensity in the pipelines of piston ICEs by 1.3–2.5 times. A method is proposed for taking the thermomechanical unsteadiness into account in thermal calculations by applying the heat transfer mobility correction coefficient for classical equations that are used to calculate the local heat transfer coefficient.

Features of the gas dynamics and local heat transfer in intake system of piston engine with supercharging

Comparison of experimental research results of gas dynamics and instantaneous local heat transfer in the intake pipes for piston internal combustion engines (ICE) without and with supercharging are presented in the article. Studies were conducted on full-scale experimental setups in terms of gas dynamic nonstationarity, which is characteristic of piston engines. It has been established that the turbocharger installation in a gas-air system of piston internal combustion engine leads to significant differences in the patterns of change in gas-dynamic and heat transfer characteristics of flows. These data can be used in a modernization of piston engines due to installation of a turbocharger or in a development of gas-air systems for piston ICE with supercharging.

Application of FEM Analysis for Evaluation of the Stress and Deformation Distributions in the Top Layer of A390.0 Alloy During Friction

Abstract The paper presents an analysis of the effect of shape of primary silicon crystals on the sizes of stresses and deformations in a surface layer of A390.0 alloy by Finite Elements Method (FEM). Analysis of stereological characteristics of the studied alloy, performed based on a quantitative metallographic analysis in combination with a statistical analysis, was used for this purpose. The presented simulation tests showed not only the deposition depth of maximum stresses and strains, but also allowed for determining the aforementioned values depending on the shape of the silicon crystals. The studied material is intended for pistons of internal combustion engines, therefore the analysis of the surface layer corresponded to conditions during friction in a piston-cylinder system of an internal combustion engine having power of up to 100 kW. The obtained results showed important differences in the values of stresses and strains up to 15% between various shape of the silicon crystals. Crystals with sharp edges caused higher stresses and deformation locally than those with rounded shapes.

Models and methods for analysis of temperature and thermomechanical fields in the bodies of complex shape in specialized intelligent system

The design of axisymmetric bodies of complex form, taking into account temperature and thermomechanical fields, is the object of research. To model these fields need to solve boundary value problems for differential equations with partial derivatives. Structural (R-functions) and regional structural methods are used to solve the boundary value problems of thermal conductivity and thermoelasticity. CAD, meeting modern requirements, should include systems based on knowledge. Also, improving the efficiency of CAD is achieved thanks to the development of methods of solution of thermal conductivity and thermoelasticity tasks in the bodies of complex form. Using created structures, we receive more stable and accurate solution of the problem of analysis of thermal and thermomechanical fields in the considered objects. The specialized intelligent system is created. It contains a database of knowledge: a database of geometric forms of designed objects and methods of solving of relevant problems; a database of rules which allow to automate the choice of method and structure of solutions, equations of boundary of its areas; other information, required to increase the degree of automation of computer modelling. Created system creates the program on RL language for some programming system (PS), which solves the problem. Created system is production system. The pictures of temperature and thermomechanical fields are studied with the help of created system in axisymmetric bodies of complex form – pistons of internal combustion engine (ICE), homogeneous and consisting of composite materials. The impact of insert material, form and location on the picture of the temperature and thermomechanical fields in these ICE pistons is researched. These researches help to design these objects in order to reduce the temperature in the critical points of the object. This improves the thermal regimes in these objects, increase their strength, reliability and durability.

The Influence of Piston Internal Combustion Engines Intake and Exhaust Systems Configuration on Local Heat Transfer

The improvement of work processes of piston engines to boost the technical and economic parameters is the main objective in the field of power engineering. The improvement of the gas exchange processes (intake and exhaust processes) quality is one of the possible profiles to improve the efficiency and reliability of piston internal combustion engines. The study of the instantaneous local heat transfer at flow unsteadiness is one of the objectives of the experimental studies of the thermomechanical processes in the intake and exhaust systems of the engines. The influence of configuration of the intake and exhaust pipes on the heat transfer intensity is a relevant engineering problem. The local heat transfer intensity data serves as the basis to determine the basis for determination of heating of the air (at intake), cooling exhaust gas (at exhaust), calculation of thermal stresses in the nodes and details of intake and exhaust systems. The article presents the results of the experimental investigation of the instantaneous local heat transfer (taking into account the hydrodynamic nonstationarity) in the intake and exhaust pipes of different configurations for piston internal combustion engines. It is established that the cross profiling of the intake and exhaust pipes of piston engines leads to 5-20% decrease in the local heat transfer intensity depending on the crankshaft speed.

Влияние конфигурации газовоздушных трактов поршневых двигателей внутреннего сгорания на локальную теплоотдачу

Влияние конфигурации газовоздушных трактов поршневых двигателей внутреннего сгорания на локальную теплоотдачу

Turning process monitoring of internal combustion engine piston’s cylindrical surface

In this paper the monitoring method of turning process of combustion engine piston’s cylindrical surface is proposed. During this process, the PCD diamond tool cuts the piston’s cylindrical surface with the 3 grooves. The first groove is made in the cast iron insert. In case, when the machining allowances are selected inappropriately, the tool cuts the cast iron insert and consequently generates the reject. The proposed monitoring system based on vibration signals analysis enables the detection of these critical situations and react, in order to maintain the production quality.

Analysis of methods for improvement of thermal stability of pistons of tractor diesel engines

The article considers the applied methods for improving the thermal strength of pistons of internal combustion engines. Tractor diesels with combustion chamber in the piston have the greatest rate of temperature change at load rise and release, as well as the highest values of temperature gradients. The highest thermal loads occur in pistons with a semi-open combustion chamber. Periodic thermal loads with high value of temperature gradient lead to thermal fatigue fractures. Such fractures may begin with the appearance of cracks on the edge of combustion chamber. The presence even of a small crack on the edge of combustion chamber leads to its further growth, which can cause the destruction of piston. The main causes of cracks formation on the edge of combustion chamber are the alternating stresses induced from alternating gas pressure in cylinder during the working cycle; the low-frequency oscillations of the piston temperature arising from the changing of operation modes of engine; the high-frequency cyclical thermal oscillations caused by the temperature change of material in the surface layer of combustion chamber for each working cycle. The most common design and technology solutions improving the thermal strength of pistons are the following ones: the change of the edge radius of combustion chamber throat; the reinforcement of combustion chamber edge with more heat-resistant materials; the use of materials with high thermal stability for manufacture of pistons; the artificial heat insulation of piston or its cooling by oil. The disadvantage of use of cooling oil gallery is the acceleration of oil aging process. The alternative solution is to limit the heat supply to the walls of combustion chamber by means of heat protection coating applied by gas-flame, detonation or electric-arc way. The easiest way to improve the thermal strength of diesel piston with a semi-open combustion chamber is the design change.

The Influence of Laser Surface Remelting on the Microstructure of EN AC-48000 Cast Alloy

Abstract Paper present a thermal analysis of laser heating and remelting of EN AC-48000 (EN AC-AlSi12CuNiMg) cast alloy used mainly for casting pistons of internal combustion engines. Laser optics were arranged such that the impingement spot size on the material was a circular with beam radius rb changes from 7 to 1500 μm. The laser surface remelting was performed under argon flow. The resulting temperature distribution, cooling rate distribution, temperature gradients and the depth of remelting are related to the laser power density and scanning velocity. The formation of microstructure during solidification after laser surface remelting of tested alloy was explained. Laser treatment of alloy tests were perform by changing the three parameters: the power of the laser beam, radius and crystallization rate. The laser surface remelting needs the selection such selection of the parameters, which leads to a significant disintegration of the structure. This method is able to increase surface hardness, for example in layered castings used for pistons in automotive engines.

Design and Preparation of Stepwise Functionally Graded Materials Used for Internal Combustion Engine Piston Applications

This work includes the design and preparation of a(Low carbon steel / AL2O3) stepwise functionally graded crown part of an internal combustion engine piston. Powder technology technique, has been studied to improve engine thermal efficiency by creating semi adiabatic combustion chambers, where ceramic phase facing the hot combustion gases, while metallic phase assembling with other parts of the piston. Finite element method ABAQUS program had been used to minimize nucleated residual stresses generated under fabrication process and service work conditions by designing the compositional graded of stepwise FGM within specific dimensions, in addition to temperature distribution across FGM thickness. Then the fabricated specimens had SEM imaging, physical and mechanical property inspection. The results also show that linear transition from metal to ceramic structure can provide minimum residual stresses under all conditions, using stepwise FGM can improve engine heat efficiency by doubling the crown surface temperature,(622) ºC, comparing with steel crown, (322) ºC, under the same applied heat flux. Physical inspections show limited relative density, (48.5) %, with high total porosity structure, (53.3) %, can be performed by this fabrication method. Mechanical tests results show that the layers’ hardness increase with increasing ceramic content, and decrease with increasing pores percentage. Compression test shows the ability of suggested stepwise FGM to withstand service work stresses of combustion chamber without failure.