petrol engine exhaust valve design, int. j. mech. eng. & rob. res. 2014 b seshagiri rao and d...

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Int. J. Mech. Eng. & Rob. Res. 2014 B Seshagiri Rao and D Gopi Chandu, 2014

ISSN 2278 – 0149 www.ijmerr.com

Vol. 3, No. 4, October, 2014

© 2014 IJMERR. All Rights Reserved

Research Paper

PETROL ENGINE EXHAUST VALVE DESIGN,ANALYSIS AND MANUFACTURING PROCESSES

B Seshagiri Rao1* and D Gopi Chandu1

*Corresponding Author: B Seshagiri Rao � [email protected]

The aim of this paper is to design an exhaust valve for a four wheeler petrol engine usingtheoretical calculations. Manufacturing process that is 2D drawings is drafted from the calculationsand 3D model and transient thermal analysis is to be done on the exhaust valve when valve isopen and closed. Analysis is done in ANSYS. Analysis will be conduct when the study statecondition is attained. Study state condition is attained at 5000 cycles at the time of when valveis closed is 127.651 sec valve is opened 127.659 sec.The material used for exhaust valve isEN52 steel. We are doing material optimization bydoing analysis on both materials EN52 andEN59.Static Modal analysis the exhaust valve to determine mode shapes of the valve for numberof modes.

Keywords: Petrol Engine, Exhaust Valve Design, Analysis, Manufacturing Processes

1 Mechanical Engineering Department, Mother Teresa Institute of Science and Technology, Khammam, Telangana-507 303.

INTRODUCTION

The valves used in the IC engines are of threetypes: Poppet, mushroom valve, Sleeve valveor Rotary valve. Of these three types, Poppetvalve is most commonly used. Since both theinlet and exhaust valves are subjected to hightemperatures of 1930°C to 2200°C during thepower stroke, therefore, it is necessary thatthe materials of the valves should withstandthese temperatures. The temperature at theinlet valve is less compared to exhaust valve.Thus the inlet valve is generally made ofnickel chromium alloy steel and exhaust valveis made of silchrome steel.

About Valves

Engine Valve is one of the main parts whichare used in all IC Engines. Each cylinder in

Figure 1: Valve Dimensions

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the engine has one inlet and one exhaustvalve. Now a days engine are designed withmulti valves viz., two inlet and one exhaustor Two inlet and Two exhaust valves whichprevents air pollution and improves engineefficiency.

Function of Inlet Valve

The inlet which operates by the action ofTappet movement, allows air and fuel mixtureinto the cylinder.

Function of Exhaust Valve

The exhaust valve allows burnt gases toescape from the cylinder to atmosphere.

Valve Efficiency

Depends on the following characteristics likeHardness, Face roundness and slidingproperties capable to withstand hightemperature etc.

Design Calculations of Exhaust Valve

Figure 2: Exhaust Valve

Description of the Physical System

The geometry of the exhaust valve is shownin Figure 3. The exhaust valve sits on thecylinder head of a combustion chamber. Theengine coolant liquid passes around thecylinder liner and the water passages inthecylinder head. The valve pops up and downto let the exhaust gases leave the combustionchamber.

The up-and-down motion of the valvetakes place with the help of a rocker leverwhich is connected to the push rod. The pushrod rests over cams on the camshaft. Thevalve is spring loaded. The spring keeps thevalve connected to the camshaft during its

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Figure 3: Description of the Physical System

motion. After the expansion process, theexhaust gases, at high temperature, arepurged through the exhaust valve and as aresult the temperature of the exhaust valveincreases. In order to avoid any damage tothe exhaust valve due to this hightemperature, heat must be continuouslytaken away from the valve. This is achievedwhen the valve is in contact with its seat. Asthe exhaust valves touch its seat, a significantdrop in exhaust valve temperature occurs.

Analysis Results

Result when valve is closed at study state at5000 cycles, at time 127.651 sec materialproperties: Thermal Conductivity - 0.22w/mmk.

Specific Heat - 1168 j/kg k

Density - 0.0000027 kg/mm3

Figure 4: Contour Plot Thermal Stresses

Figure 5: Thermal Flux

Figure 6: 3D Thermal Stresses

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Figure 8: Contour Plot Thermal Stresses

Transient Thermal Analysis of rectan-gular fin body using magnesium alloy

Material Properties: Thermal Conductivity- 0.135w/mmkSpecific Heat - 1233 j/kg kDensity- 0.00000185 kg/mm3

Result when valve is open at study state at5000 cycles, at time 127.659 Sec.

Figure 7: 3D Thermal Flux

Figure 9: 3D Thermal Flux

Table 1: Physical Properties

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Specific Heat - is the ratio of heat requiredto raise the temperature of a certain weightof material by 1 Deg C to that required toraise the temperature of the same weight ofwater by 1 Deg C, Coefficients of ThermalExpansion for Valve Guide Material (between0 and 200 Deg C, in 10 exp(-6).K(-1)). CastIron 11, Phosphor Bronze 18, AluminumBronze 18

*Note - To find the expansion at 300 DegC of a valve with a stem diameter of 0.275”in 214N material. (Assuming the stemdiameter was measured at 20 Deg. C), thetemperature difference is (300 Deg C - 20Deg C) = 280 Deg C.Stem diameter xtemperature difference x coefficient ofthermal expansion = Expansion of Valve

Ie: 0.275 x 280 x 0.0000175 = 0.0013

6.0 PTA Deposition Plasma TransferredArc Process ( PTA Process ) is used to fusea metallic coating to a substrate in order toimprove its resistance against wear and/orcorrosion. This technique is called hardfacing,wear surfacing, or more commonly wearfacing. During the process, metal powder isfed into a molten weld puddle (fusion bath)generated by the plasma arc at hightemperature (up to 20,000 °C). All weldingparameters, including powder feed, powerinput, plasma gas and shielding gas, as wellas torch and workpiece movement areautomatized and computer controlled inPLASMA TEAM equipment. PTA hardfacingis a true welding process, with a metallic bondbetween the substrate and deposit. Depositthickness can range from 0.6 to 6.0 mm, widthfrom 3 to 10 mm when using a single pass;multipass welding reaches deposit

thicknessup 20 mm and width over 30mm.The core of PTA process is PLASMA.The plasma (a gas sufficiently ionized to beelectrically conductive) can be viewed as thenatural state of matter (the so called fourthstate of matter), with the other states existingonly as variants to the normal. Plasma stateconstitutes more than 99.9% of all matter inthe universe. Thermal plasma describes agas which is at least 1% ionized, with atemperature greater than 13,000 °C, and isa good electrical conductor.

Product Parameters

Observations

• Improper bonding may take placeleading to the reduced strength of thecomponent and as a result thecomponent will tend to fail

• If the upset force is less then also thestrength of the weld will be less therebyincreasing the tendency of thecomponent to fail.8.0 ManufacturingResults

Table 2: Product Parameters

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Valve Process Flow with Head to PinFriction Welding

1. One halve of the bar is upsetted andthen forged.

2. Now the forged head is welded toanother bar by friction welding.

3. Deburring is done to remove the flashgenerated in friction welding

4. The valves obtained are straightenedand given as input to rough centrelessGrinding operation..

Friction Welding Operation in “Head toPin” Process.

Figure 10: Head Pin

TENSILE STRENGTH

Friction welding operation was carried withHead to pin and some checks wereconducted to know the mechanicalproperties of the welded joint.

Tensile strength for different diameter barsafter friction welding

Bar diameter = 6.90 mm

Reqiired tensile strength = 89-134 kgf/mm2

Table 3: Tensile Strength of 6.9 mm

SampleNo.

1

2

3

4

5

6

7

8

9

10

Tensile strength(kgf/mm2)(Pin to Pin)

110

107

111

114

112

105

108

109

113

108

Tensile strength(kgf/mm2)

(Head to Pin)

115

110

114

113

105

109

111

114

113

107

Figure 11: Tensile Strength of 6.9mm

CONCLUSION

1. Material Saving:

1. 45665 - Rs. 2.59 Valve2. 40574 - Rs. 1.46Valve3. 40579 - Rs. 1.40Valve

2. Grinding Cost Saving :

1. 45665 - Rs. 0.99 Valve2. 40574 - Rs. 0.65Valve3. 40579 - Rs. 0.65Valve

3. Totally four operations eliminated forthese part nos.

4. Total savings per annum - Rs.20.0 lakhs

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5. In-direct benefit: This becomes a Poke-Yoke to avoid reverse material forgingwhich is one of the critical customercomplaint.

6. Lead time reduced by 2 days.

REFERENCES

1. Avinash Kumar Agrawl, Shravan KumarSingh, Shailendra Sinha and MritunjayKumar Shukla (2004), “Effect of EGR onthe Exhaust Gas Temperature andExhaust Opacity in Compression IgnitionEngines”, Sadhana, Vol. 29, No. 3, pp.275-284.

2. G Brecq 1 and O Le Corre (2005),“Modeling of in - Cylinder PressureOscillations Under Knocking Condition:Interodiction to Pressure Envelope

curve SAE2005”.

3. Hirt C W, Amsden A A and Cock J L(1974), “Journal of ComputationalPhysics”, Vol. 14.

4. J B Heywood (1988), “InternalCombustion Engine Fundamentals”,McGraw -Hill, New York.

5. Leppard W R (1982), “Individual-cylinderKnock Occurrence and Intensity in MultiCylinder Engine”, SAE Technical PaperN 820074.

6. Lu (2009), “C,Q: Multi-dimensionalNumerical Simulation for CombustionProcess of CA6DL1- 30 Petrol Engine.Jiangsu University”, Jiangsu.

7. R K Rajput (2008), “A Text Book ofInternal Combustion Engine”, 2nd EditionLaxmi publications Pvt. Ltd.

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