www.semargroup.org, www.ijsetr.com ISSN 2319-8885 Vol.03,Issue.21 September-2014, Pages:4283-4289 Thermal Analysis of Copper Coated 2 Stroke Spark Ignition Engine KHALDOON FAWZI MUKHLIF 1, DR. E. RAMJEE 2 1 PG Scholar, Dept of Mechanical Engineering, JNTUH College of Engineering, Hyderabad, India, E-mail: khaldoonfawzi@yahoo.com. 2 Professor, Dept of Mechanical Engineering, JNTUH College of Engineering, Hyderabad, India, E-mail: e_ramjee@jntuh.ac.in. Abstract: Piston temperature has considerable influence on efficiency, emission and performance of the SI engine. Piston and liner are the contributors of heat transfer to the coolant through which heat is rejected, the use of a thermal barrier in the piston and liner has become attractive. Though the copper coatings have proved to be a promising technique, In the present work the Piston and cylinder Models are done by using PRO-Engineer, then analyzed for structural, thermal with and without copper coated using ANSYS software 14.5, which is a powerful Finite Element analysis In the process to get stresses, the temperature distribution in the piston and combustion chamber has been evaluated using this soft. The copper coated on piston head and inside of the combustion chamber of the engine. In the present thesis, work has been taken up on the following aspects. Temperature distribution and heat flow through the piston and combustion chamber of SI engine with and without copper coated. Temperature distribution, Thermal gradient vector sum and heat flux vector sum vector sum through the piston, liner and cylinder head of the conventional SI engines with and without copper coated using ANSYS 14.5. FEA analysis of 2 stroke SI engine to measure the temperature at points where it is not possible to find out practically and to observe the heat flow inside the piston. Structural analysis to find von misses stress and displacement vector sum with and without copper coated using ANSYS. From the thermal analysis, the temperature distribution through the piston and cylinder with copper coated more than the temperature distribution through the piston and cylinder without copper coated and from the structural analysis, the von misses stress and displacement vector sum with copper coated more than the von misses stress and displacement vector sum without copper coated. Keywords: FEA Analysis, Copper, SI Engine, Thermal Gradient Vector. I. INTRODUCTION I.C. engine converts the reciprocating motion of piston into rotary motion of the crankshaft by means of a connecting rod. The piston which reciprocating in the cylinder is very close fit in the cylinder. Rings are inserted in the circumferential grooves of the piston to prevent leakage of gases from sides of the piston. Usually a cylinder is bored in a cylinder block and a gasket, made of copper sheet or asbestos is inserted between the cylinder and the cylinder head to avoid ant leakage. The combustion space is provided at the top of the cylinder head where combustion takes place. The connecting rod connects the piston and the crankshaft. The end of the connecting rod connecting the piston is called small end. A pin called gudgeon pin or wrist pin is provided for connecting the piston and the connecting rod at the small end.. The other end of the connecting rod connecting the crank shaft is called big end. When piston is moved up and down, the motion is transmitted to the crank shaft by the connecting rod and the crank shaft makes rotary motion. The crankshaft rotates in main bearings which are fitted the crankcase. A flywheel is provided at one end of the crankshaft for smoothing the uneven torque produced by the engine. There is an oil sump at the bottom of the engine which contains lubricating oil for lubricating different parts of the engine [1]. II. WORKING PRINCIPLE OF I.C. ENGINE/ FOUR STROKE CYCLE ENGINE A mixture of fuel with correct amount of air is exploded in an engine cylinder which is closed at one end. As a result of this explosion, heat is released and this heat causes the pressure of the burning gases to increase. This pressure forces a close fitting piston to move down the cylinder. The movement of piston is transmitted to a crankshaft by a connecting rod so that the crankshaft rotates and turns a flywheel connected to it. Power is taken from the rotating crank shaft to do mechanical work. To obtain continuous rotation of the crankshaft the explosion has to be repeated continuously. Before the explosion to take place, the used gases are expelled from the cylinder, fresh charge of fuel and air are admitted in to the cylinder and the piston moved back to its starting position. The sequences of events taking place in an engine are called the working cycle of the engine. The sequence of events taking place inside the engine are as follows 1.Admission of air or air-fuel mixture inside the engine cylinder (suction), 2. Compression of the air or air fuel mixture inside the engine (compression) 3. Injection of fuel in compressed air for Copyright @ 2014 SEMAR GROUPS TECHNICAL SOCIETY. All rights reserved.
ignition of the fuel or ignition of air-fuel mixture by an electric spark using a spark plug to produce thermal power inside the cylinder (power ) 4. Removal of all the burnt gases from the cylinder to receive fresh charge (exhaust) Note: Charge means admitting fresh air in to the cylinder in the case of compression ignition engines (diesel engines) or admitting a mixture of air and fuel in to the cylinder in the case of spark ignition engines [2]. III. TWO STROKE CYCLE ENGINE (PETROL ENGINE) In two stroke cycle engines, the whole sequence of events i.e., suction, compression, power and exhaust are completed in two strokes of the piston i.e. one revolution of the crankshaft. There is no valve in this type of engine. Gas movement takes place through holes called ports in the cylinder. The crankcase of the engine is air tight in which the crankshaft rotates. A. Two stroke cycle: Upward stroke of the piston (Suction + Compression) When the piston moves upward it covers two of the ports, the exhaust port and transfer port, which are normally almost opposite to each other. This traps the charge of airfuel mixture drawn already in to the cylinder. Further upward movement of the piston compresses the charge and also uncovers the suction port. Now fresh mixture is drawn through this port into the crankcase. Just before the end of this stroke, the mixture in the cylinder is ignited by a spark plug Thus, during this stroke both suction and compression events are completed. B. Downward stroke (Power + Exhaust) Burning of the fuel rises the temperature and pressure of the gases which forces the piston to move down the cylinder. When the piston moves down, it closes the suction port, trapping the fresh charge drawn into the crankcase during the previous upward stroke. Further downward movement of the piston uncovers first the exhaust port and then the transfer port. Now fresh charge in the crankcase moves in to the cylinder through the transfer port driving out the burnt gases through the exhaust port. Special shaped piston crown deflect the incoming mixture up around the cylinder so that it can help in driving out the exhaust gases. During the downward stroke of the piston power and exhaust events are completed [1]. C. Advantages and Disadvantages Of Two Stroke Engines Two-stroke engines have certain advantages as well as disadvantages compared to four-stroke engines. In the following sections the main advantages and disadvantages are discussed briefly. Advantages of Two-stroke Engines As there is a working stroke for each revolution, the power developed will be nearly twice that of a Fourstroke engine of the same dimensions and operating at the same speed. The work required to overcome the friction of the exhaust and suction strokes is saved. KHALDOON FAWZI MUKHLIF, DR. E. RAMJEE As there is a working stroke in every revolution, a more uniform turning moment is obtained on the Crankshaft and therefore, a lighter flywheel is required. Disadvantages of Two-Stroke Engines High speed two-stroke engines are less efficient owing to the reduced volumetric efficiency. With engines working on Otto cycle, a part of the fresh mixture is lost as it escapes through the exhaust port during scavenging. This increases the fuel consumption and reduces the thermal efficiency. Part of the piston stroke is lost with the provision of the ports thus the effective compression is less in case of two-stroke engines. Fig.1. Two stroke cycle engine. IV. INTRODUCTION TO COPPER Copper is a chemical element with the symbol Cu (from Latin: cuprum) and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; a freshly exposed surface has a reddish-orange color. It is used as a conductor of heat and electricity, a building material, and a constituent of various metal alloys. A. Applications The major applications of copper are in electrical wires (60%), roofing and plumbing (20%) and industrial machinery (15%). Copper is mostly used as a pure metal, but when a higher hardness is required it is combined with other elements to make an alloy (5% of total use) such as brass and bronze. A small part of copper supply is used in production of compounds for nutritional supplements and fungicides in agriculture. Machining of copper is possible, although it is usually necessary to use an alloy for intricate parts to get good machinability characteristics. B. Project Objective There are three main objectives that must be achieved: 1. To develop the geometry of the piston using PRO/ENGINEEEING software.
Thermal Analysis of Copper Coated 2 Stroke Spark Ignition Engine 2. To investigate Temperature distribution, Thermal gradient vector sum and heat flux vector sum vector sum through the piston, liner and cylinder head of the conventional SI engines. with and without copper coated using ANSYS. 3. Structural analysis to find von misses stress and displacement vector sum with and without copper coated using ANSYS. V. METHODOLOGY A. General Basically in this Project Solid Model of a Piston and cylinder are developed in Pro-E and is further imported into the Ansys Package for Analysis Phase. So here the two Software s used are. 1- Pro-E 2- Ansys B. Pro-E 1. Introduction to Pro/Engineer Pro/ENGINEER is a computer graphics system for modeling various mechanical designs and for performing related design and manufacturing operations. The system uses a 3D solid modeling system as the core, and applies the feature-based, parametric modeling method. In short, Pro/Engineer is a feature-based, parametric solid modeling system with many extended design and manufacturing applications [3]. 2. Objectives [4] Create a feature using an Extruded protrusion. Understand Setup and Environment settings. Define and set a Material type. Create and use Datum features. Sketch protrusion and cut feature geometry using the Sketcher. Understand the feature Dashboard Copy a feature Save and Delete Old Versions of an object Fig2. Assembly with copper liner. 3. Specifications of engine Engine type: 2-stroke spark ignition engine Bore Displacement = 145.5CC C. FEA Software Ansys 1. Introduction ANSYS is general-purpose finite element analysis (FEA) software package. Finite Element Analysis is a numerical method of deconstructing a complex system into very small pieces (of user-designated size) called elements. The software implements equations that govern the behaviour of these elements and solves them all; creating a comprehensive explanation of how the system acts as a whole. These results then can be presented in tabulated, or graphical forms. This type of analysis is typically used for the design and optimization of a system far too complex to analyze by hand. Systems that may fit into this category are too complex due to their geometry, scale, or governing equations. D. Procedure for Ansys Analysis The procedure for ANSYS analysis consists of three main steps: 1. Build the model. 2. Obtain the solution. 3. Review the results. 1. Build the model In this step, we specify job name and analysis title and then define the element types, element real constants, material properties and the model geometry element typesboth linear and non-linear structural elements are allowed. The ANSYS element library contains over 80 different element types. A unique number and prefix identify each element type. E.g.: PLANE-71, SOLID-96, BEAM-94 and PIPE-16. Material properties: Young s modulus [Ex] must be defined for static analysis. If we have to apply inertia loads [such as gravity], we define mass properties such as density [DENS]. Similarly if we apply thermal loads [temperatures], we define coefficients of thermal expansion [ALPX]. 2. Obtain the solution: In this step we define the analysis type and options, apply loads and initiate the finite element solution. This involves three phases: i. Pre-Processor phase ii. Solution Phase iii. Post-Processor phase i. Pre-Processor: Pre-Processor has been developed so that the same program is available on micro, mini, super-mini and mainframe computer system. This allows easy transfer of models from one system to the other. Pre-Processor is an interactive model builder to prepare the finite element model and input data. The solution phase utilizes the input data developed by the pre-processor, and does the solution
according to the problem definition. It creates input files to the visualization of results on the graphics screen. It displays the displacements, stresses, temperatures, etc. on the screen in the form of contours. ii. Solution The solution phase deals with the solution of the problem according to the problem definitions. All the tedious work of formulating and assembling of matrices are done by the computer and finally displacements and stresses are given as output. iii. Post Processor The post-processing phase of the ANSYS program follows the preprocessing and solution phases. With this portion of the program, the user may easily obtain and operate on the results calculated in the solution phase through a very complete set of user-friendly post-processing features. These results may include displacements, temperatures, strains and stresses, velocities and heat flows. The output from the postprocessing phase of the program is in display and/or tabular report form. Because the post-processing phase is fully integrated with the ANSYS preprocessing and solution phases, the user can examine results immediately. It is a powerful user-friendly post-processing program. Using interactive color graphics, it has extensive plotting features for displaying results obtained from FEM. One picture of analysis results can often reveal in seconds what would take engineer hours to assess from numerical printout. The engineer may also see important aspect of the results that could be easily missed in stock of printout. Employing state of the art image enhancement techniques, it facilities viewing of contours of stresses, displacements, temperatures etc. Table 1: Steps followed in Ansys Software KHALDOON FAWZI MUKHLIF, DR. E. RAMJEE advances in computer technology and CAD systems, complex problems can be modeled with relative ease. Several alternate configurations can be tried out on a computer before the first prototype is built. The basics in engineering field are must to idealize the given structure for the required behavior. In the Finite Element Method, the solution region is considered as many small, interconnected sub regions called Finite elements [5]. B. Elements and Its Types In general, the finite elements are classified. 1. Based on dimension as One dimensional element Line element Two dimensional element Triangular and quadrilateral elements. Three dimensional elements Tetrahedral and hexahedral elements. 2. Based on material properties Linear element Non-linear element 3. Based on degree of freedom Translational one, two or three degrees of freedom Rotational one, two or three degrees of freedom VII. ANALYSIS USING ANSYS A. Thermal Analysis of Cylinder, Piston with Copper Lining Assembly Fig3.Imported Model from Pro/Engineer with copper lining. VI. FINITE ELEMENT METHOD A. Introduction To Finite Element Method The Finite Element Method has been a powerful tool for the numerical solution of a wide range of engineering problems. Applications range from deformation and stress analysis of automotive, aircraft, building, defense, and missile and bridge structures to the field of analysis of dynamics, stability, fracture mechanics, heat flux, fluid flow, magnetic flux, seepage, and other flow problems. The basic idea in the Finite Element Method is to find the solution of complicated problems with relatively easy way.with the Fig4. Meshed Model with copper lining.
Thermal Analysis of Copper Coated 2 Stroke Spark Ignition Engine B. Structural Analysis Of Cylinder, Piston with Copper Lining Assembly Fig5.Nodal temperature with copper lining(k) Fig8. Displacement vector sum with copper lining (mm). Fig6.Thermal gradient vector sum with copper lining (k/mm). Fig9.Von misses stress with copper lining(mpa). Fig7. Heat flux vector sum with copper lining (w/mm 2 ). Fig.9. Von misses total strain with copper lining.
Table.2. Structural analysis with copper lining Table.3. Structural analysis without copper lining Table.4.Thermal analysis with copper lining KHALDOON FAWZI MUKHLIF, DR. E. RAMJEE VIII. RESULTS AND DISCUSSIONS By using Ansys software analysis (Structural, Thermal) of the two stroke spark ignition engine has been carried out successfully. By using the Analysis obtained from the Structural Analysis of copper coated, The value of Maximum Displacement vector sum is found to be 0.014119. Von Misses Stress is found to be 28.451MPa. By using the Analysis obtained from the Structural Analysis without copper coated, the value of Maximum Displacement vector sum is found to be 0.013471. and the value of Maximum Von Misses Stress is found to be 22.076MPa. By using copper coated in the engine lead to increase the Von misses stress, the copper coated engine has higher Von Misses Stress from without copper engine. so we concluded that the copper coated was the best. From the thermal analysis of tow stroke engine, the temperature distribution with copper coated engine higher than the temperature distribution without copper coated engine. Maximum elongations and temperature are observed at the piston head and cylinder head section and minimum elongation and temperature variation at the root of the engine. The copper coated has small effect in the displacement vector sum, so the engine with copper coated better than the engine without copper coated. Table.5.Thermal analysis without copper lining Table.6.Thermal analysis with copper lining IX. CONCLUSION The copper coated has a significant effect on the overall stresses and temperature. By using Ansys software analysis (Structural, Thermal) of the two stroke spark ignition engine has been carried out successfully. By using the Analysis obtained from the Structural Analysis of copper coated, The value of Maximum Displacement vector sum is found to be 0.014119. The value of Minimum Displacement vector sum is found to be 0 and the value of Maximum Von Misses Stress is found to be 28.451MPa. The value of Minimum Von Misses Stress is found to be 0.180E-04 Map. By using the Analysis obtained from the Structural Analysis without copper coated, the value of Maximum Displacement vector sum is found to be 0.013471. The value of Minimum Displacement vector sum is found to be.0 and the value of Maximum Von Misses Stress is found to be 22.076MPa. The value of Minimum Von Misses Stress is found to be 0.270E-04 Map. The temperature distribution in the piston and the cylinder with copper coated higher than the temperature distribution in the piston and the cylinder without copper coated because in copper coated engine the, copper has high thermal conductivity this lead to more dissipated of the heat through the engine. If the thermal conductivity is increased, the amount of the heat flow will be high. Therefore the material type with high thermal conductivity is considered better than the material type of low thermal conductivity. This
Thermal Analysis of Copper Coated 2 Stroke Spark Ignition Engine means that the engine with copper coated better than the engine without copper coated due to high thermal conductivity of copper. ANSYS program in which finite element mesh generated employing node elements predicted isotherms well for copper coated piston, liner, copper coated cylinder head, conventional piston, liner, and conventional cylinder head for the copper coated and conventional engines. From the above discussions it is clear that the increase in the temperature is high in the copper coated engine compared to conventional engine. X. REFERENCES [1] B. Heywood John, Internal Combustion Engine Fundamentals,McGraw-Hill, New York. [2] V. Ganesan., Internal combustion engines, Tata Mc Graw- Hill Publications. [3] Roger Toogood,Pro/Engineer Wildfire 4.0: Tutorial And Multimedia CD, ISBN: 978-1-58503-415-4. [4] Louis Gray Lamit, Introduction to Pro/ENGINEER Wildfire 2, 2004. [5] Gantla Shashidhar Reddy and N. Amara Nageswara Rao, Modeling and Analysis Of Diesel Engine Piston, International Journal of Mathematics and Engineering, 206 (2013) 1994 2027, ISSN 0976 1411. Author's Profile: interest. Khaldoon fawzi mukhlif, Received his Bachelor Degree in Mechanical Engineering & Education from University of Anbar, IRAQ. Presently he finished his Master of Technology (Thermal Engineering) in Jawaharlal Nehru Technological University, Hyderabad, INDIA. His research Dr.E. Ramjee Professor of Examination, Mechanical Engg.. Areas of Interest IC. Engines, Fuels, Combustion and Environment, Thermal Engineering.