Investigation of Thermal Behaviour of (Steel Alloy (44K2), Titanium Aluminide, SiO2, Al2O3, ZrO2) Materials on Internal Combustion Engine Valves (original) (raw)
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Thermal Analysis on Exhaust Valve with Thermal Barrier Material
2018
An exhaust valve is the important component in the engine system due to its direct involvement in the combustion and experiencing the high temperature and pressure from the hot gases during the exhaust stroke based on the valve timing for opening and closing. Because of this exposure to exhaust, high thermal loads are induced which leads to the failure of the valve. Therefore, a cooling provision is must to reduce the temperatures due to heat transfer effect or to increase the heat dissipation rate through valve by maintaining it at optimum thermal conditions. The cooling provisions are by filling the valve with sodium making valve hollow inside or by using the thermal barrier coatings on the outer surface of valve. In this an attempt is made to study the importance of cooling provision by doing thermal analysis on the valve geometry with different approaches under full load conditions of engine. The valve geometry is modelled using CAD software and the thermal analysis at steady st...
An approach for the thermal analysis of internal combustion engines' exhaust valves
Exhaust valve is subject to thermal loading due to high temperature and pressure. Exhaust valve is subdivided to several zones to isolate the effect of each part. Heat transfer for each subdivision is evaluated during engine operating cycle. Temperature maps through valves allows identifying region exposed to maximum temperature. a b s t r a c t Intake and exhaust valves are important components of internal combustion engines, which are used to control the inflow and outflow of gases. Such valves are subject to thermal loading due to high temperature and pressure inside the cylinder that must tolerate the limit of material temperature for a sustainable and optimal operation. The present study constitutes a contribution to predict the temperature maps of intake and exhaust valves considering the real conditions of an engine operation. An adequate subdivision of the valve is used to better assess the effect of each part of the cylinder head. Therefore, the instantaneous heat transfer coefficient and adiabatic wall temperature for each subdivision are evaluated during the four-stroke of an engine. The average values of these parameters are calculated and introduced as boundary conditions in a finite element model implemented in the commercial code Ansys-CFX. To facilitate the simulations runs of the proposed model, APDL (ANSYS Parametric Design Language) code is developed to extract the thermal map. As an application, this methodology is used to highlight the temperature maps and to show the region of extreme temperature and heat flux in the aim of avoiding any damage.
Thermal and Mechanical Analysis of Intake Valve
Valves are the most important and critical part of an Internal Combustion engine. Many factors matters while designing the intake and exhaust valve of an engine such as gas inflow, material properties, oxidation characteristics, fatigue strength, thermal strength, configuration of coolant flow and cylinder head. In this, we had made the model of Inlet valve of the two wheeler in NX and had analysed it in the ANSYS. First, we had selected the different materials that were suitable for the Intake valve. After some research, we had selected two materials (SUH3, SAE1541) which can perform better for Intake valve. After this, we had performed thermal, thermal-coupled structural analysis. In this, we observed the temperature distribution over the Intake valve and deformation of Inlet valve.
Combustion Engines, 2013
According to the current trend to reduce the valvetrain movable masses in combustion engines lightweight valves are used increasingly. They can be made of light alloys from the TiAl alloy group or of ceramic materials such as silicon nitride. They are often coated with additional protective layers to reduce the resistance of friction or the wear intensity. They may also be a hollow structure made of steel with internal reinforcing ribs. Compared to traditional full steel valves they are characterized by different temperature gradients when working in a valvetrain. As a result, their working change, particularly the intensity of the heat transfer and wear. The paper presents valve models developed with the FEM technique for several design and material configurations for lightweight intake and exhaust valves operating under conditions similar to those made of steel. Also the temperature gradients of the discussed valves have been included and compared to those of full steel valves.
Methods for thermomechanical analysis of thermal barrier coatings in diesel engines
Surface and Coatings Technology, 1987
Thermal barrier coatings applied to in-cylinder surfaces of diesel engines are subject to large thermomechanical loads as a result of the transfer of heat from the combustion gases. The thermal loads produce high temperatures and high temperature gradients in the coating. Owing to the intermittent cyclical nature of the engine heat transfer and the low conductivity of thermal barrier coatings, large cyclic surface temperature transients are superimposed on the already high steady state temperatures. In addition, there are significant thermal transients produced by rapid variations in the engine operating conditions (engine speed and load). Recent methods developed by researchers rigorously couple the calculation of spatially and time-resolved in-cylinder gas phase thermal processes with the calculation of structural heat transfer and thermal stresses using finite element techniques. This makes possible a detailed analysis of the effects of steady state and transient engine heat loads on the performance of heat barrier coatings. The techniques are described in a brief and general manner but attention is otherwise directed to specific results obtained by us. Results showing the temperatures and thermal stresses produced by steady state and transient thermal loads are presented for plasma-sprayed zirconia coatings on the valves of a heavy duty highway diesel engine.
Elsevier, 2017
Industrialization and urbanization reflects in the energy demand consequences of that the world is constantly facing challenges toward the hazardous emissions from various industries and transportation systems. The emissions play a vital role in global warming, ozone layer depletion and imperil to the ecosystem. The survival from adverse effects due to emissions can be significantly controlled by attaining technological advancements in emission reduction. Many researchers are attracted towards engine emission controlled by adopting the metal coating on combustion chamber surfaces. Some of the researchers also attempted with ceramic coating for the components viz piston, engine head etc. The kind of metal coatings acts as thermal barrier, and this thermal insulation decreases the rate of heat transfer from the combustion chamber by restoring the heat in, itself only and controls the exhaust gas emissions. This research paper, details the various trends and innovations about the metal coating in automobile engine application. The results are evitable, in the perception of engine performance enhancement and a significant reduction of engine emission.
As per the second law of thermodynamics the efficiency of the engine depends upon the extraction of work against the heat supplied. Minimisation of heat rejection leads to increase the work. Heat rejection takes place through the engine piston, valves and cylinder heads to the surroundings. The aim of the study is to minimise this heat rejection to the surroundings. Heat transfer through the engine parts is minimised by applying the thermal barrier coating materials on the top surface of the engine piston, cylinder heads and valves. In this study an attempt is made to reduce the intensity of thermal and structural stresses by using a layer of the ceramic material, like Yttria stabilized zirconia (YSZ) which has low thermal conductivity, high thermal resistance, chemical inertness, high resistance to erosion, corrosion and high strength was selected as a coating material for engine component. This study present the effect of coating on the piston and the performance of modified four stroke petrol engine and the emission characteristics of the exhaust gas.
Design and Analysis of Exhaust Valve of an IC Engine by using Finite Element Analysis
International Journal for Research in Applied Science and Engineering Technology IJRASET, 2020
Engine is the heart of automobiles and valve mechanism is the heart of engine. There are two types of the valves are used in internal combustion engines which are intake valve and exhaust valve. Intake and exhaust valves are used to control the flow of intake fresh charge and Exhaust flue gases alternatively in Engine. They are used to seal the working space inside cylinder against the manifold and they open and close by means of what is known as the Valve gear mechanism. Exhaust valve work well in engines because the pressure inside the combustion chamber pushes valve against the seat, sealing the chamber and preventing leaks during this cycle exhaust valves are exposed to high temperature and pressure which will affect the life and performance of the engine. The aim of the project is to design an exhaust valve with a suitable material along with the three different fillet radii for a four-stroke diesel engine by using Finite Element Analysis. In exhaust valve we have considered Aluminium 7068 alloy, Silicon carbide reinforced Zirconium di-boride and Carbon fiber composite material. In this we observe the results of existing exhaust valve's stress, strain and total deformation values are compared to the modified exhaust valve design are shows tremendous change in stress, strain and total deformation of the composite material.
Eksploatacja i Niezawodność – Maintenance and Reliability
The focus of internal combustion engine development for urban vehicles is shifting towards reducing materials by making them lighter. In order to maintain thermal and flow levels, a model was developed to study the thermal behavior of valve seats during periodic contact, which can also help improve engine performance and fuel efficiency. The model, composed of two cylindrical bars in periodic contact, takes into account the evolution and topography of the contact surface. The model's performance was evaluated through various experimental studies and showed a maximum difference of 5.05% with experimental values, in good agreement with previous literature. The results showed that heat flux increases with increasing contact frequency and thermal diffusivity affects conductive transfer. This model can be used by manufacturers to evaluate cylinder head temperature and by the automotive industry to improve heat transfer in engines.
Wear mechanism study of exhaust valve system in modern heavy duty combustion engines
Wear, 2011
The increasing demands from environmental legislations are changing the conditions that the valve system is exposed to in heavy duty engines. Increased pressures, higher temperatures and lower amounts of soot which can build up a protective film are some of the increasing challenges which the system has to endure. Three pairs of valves and valve seat inserts with the same material and design properties but with different service condition have been analyzed with a variety of analytical instruments to gain information of how the wear occurs. The wear mechanisms found were a combination of oxidation, where many different oxides were found, adhesive wear, which was seen both in form of material transfer and flow lines. On top of Sample Mild and Hard there were tribo films of thickness varying from 1 to 5 m consisting of Ca, O, P, S and Zn. The film has in all cases protected the underlying surface from wear but in some cases seems to have a corrosive impact instead.