Design Considerations of Gudgeon Pin in Reciprocating Air Compressors by Semi Analytic Approach

Full Length Research Paper

Design considerations of Gudgeon pin in reciprocating air compressors by semi analytic approach

V. Ramamurti1*, S. Sridhar2, S. Mithun2, B. Kumaravel2 and S. Lavanya2

1The Indian Institute of Technology Madras, India. 2WABCO-TVS India, Chennai, India.

Accepted 17 March, 2011

The deformation and stress experienced by the Gudgeon pin of a reciprocating compressor used in air brake system is scientifically predicted when the pin is fully floating with lubricating oil surrounding it and when starved of oil. Both semi analytical approach in finite element method and simple bending theory of beams are used. Inadequacy of the beam approach is highlighted. The results obtained by both the approaches are compared. Role of clearance in piston bore and small end of connecting rod and effectiveness of lubrication are examined. Factor of safety associated with the design of Gudgeon pin is also looked into.

Key words: Gudgeon pin, semi and fully floating pin, semi analytic method, role of lubricant, factor of safety.

INTRODUCTION

Reciprocating air compressors in vehicles compress air modal superposition technique was reported by the and supply it to the air brakes. Many of the components authors (Ramamurti et al., 2011). In the present constituting the reciprocating air compressor are having investigation, the design considerations connected with design features based more on standard practices rather the Gudgeon pin of reciprocating air compressors are than on sound scientific analysis. One of the systematic presented. This is motivated by lack of scientific analysis investigations reported recently is on the pressure in literature and the inadequacies in the design variation inside the air compressor as a function of the procedure. crank angle (Venkatesan et al., 2009). An experimental investigation using optical probes was also reported (Brun et al., 2005). The dynamic analysis of the response Relevance of investigation of the inlet and discharge valves of the compressor using Gudgeon pin (Figure 1) connects the small end of the connecting rod with the piston providing a turning pair; Gudgeon pin can either turn relative to the connecting rod *Corresponding author. E-mail: [email protected]. or relative to the piston bore or turn relative to both(Ramamurti, 2009). Nomenclature: C, Clearance in the piston bore; d, l ,D-Inner Prerequisite for this function is that the Gudgeon pin diameter, one-third length and outer diameter of the Gudgeon has a sliding fit with the other two. Since the Gudgeon pin pin; n, Fourier index; pr, pθ, radial and circumferential pressure transmits the load from the connecting rod to the piston, on the pin; r1,r2, inner and outer radii of the pin; w, load per unit the deformation that it suffers during the operation must length on the pin (F/ ℓ); A1, A2, B1, B2, C, salient locations on be such that it does not have surface contact with both the Gudgeon pin; E, Young’s modulus; F, force on the simultaneously. This will lead to seizure. Besides, the connecting rod; F1, Reaction at the end of the Gudgeon pin; I, Gudgeon pin should not be stressed beyond its second moment of area of the beam; M, Bending moment of the endurance limit. beam; OX,OY,OZ, radial , axial, circumferential; coordinates in semi analytical approach; Z, Modulus of section of the pin; The Gudgeon pin is either a hollow or solid steel  ,Semi contact angle (in radians); σX, σY, σZ, Stresses in cylinder of length roughly five times its outer diameter. radial, axial and circumferential directions; θ, Angular position in This is subjected to lateral load from the connecting rod the pin. (Figure 2). The load acts for the full width of the 76 J. Mech. Eng. Res.

Figure 1. Cross section of the piston assembly.

Figure 2. Force on the gudgeon pin.

connecting rod (for nearly one third of the axial length of other hand, assumed fixed, it ignores the fact that there is the Gudgeon pin) acting over a substantial arc of the a radial clearance between the piston bore and the outer cylindrical surface of the pin. A very simple method cylindrical surface of the Gudgeon pin. However, when of analysis is to treat the pin as a simply supported beam assumed simply supported, beam approach is very easy subjected to lateral load of uniform intensity from the to analyse since the structure is statically determinate. connecting rod. This approach has two basic deficiencies. (i) The Gudgeon pin does not qualify to be treated as a beam since its length is much less than ten FORCE ANALYSIS OF GUDGEON PIN times its outer diameter. (ii) Besides the beam, when assumed as simply supported at the ends, ignores the The Gudgeon pin assembly is subjected to uniform fact that its support is along an arc of a circle. If, on the intensity of pressure in the region of the connecting rod Ramamurti et al. 77

Figure 3. Close up view of Gudgeon pin and its salient locations.

due to air compressed on the top flat face of the piston. Analytical procedure Besides it is prevented from moving axially by the circlips. The deformation of the Gudgeon pin is to be within elastic Beam approach limits under the action of the force along the width of the connecting rod for various angular positions. The This corresponds to a problem ignoring the presence of bending deformation of the Gudgeon pin is to be oil in the annular space and assuming direct contact assessed to address the adequacy of clearance between between the piston bore and the Gudgeon pin and the pin and the small end of the connecting rod and also between the Gudgeon pin and connecting rod. In this between the Gudgeon pin and piston bore. approach, even though the beam length is only five times The Gudgeon pin, in reality, is a cylinder of roughly the diameter, Euler beam theory is assumed to be valid. length 5 times its diameter, supported by lubricating oil present in the clearance on the piston bore for roughly two thirds its length with the middle one third subjected to Case (i): Contacts at B1 and B2 lubricating oil pressure on the annular space of the small end of connecting rod. The load that gets communicated Figure 3 shows the close up view of the Gudgeon pin. to the Gudgeon pin from the connecting rod acts on the The length 3ℓ of the pin is roughly divided into three parts, outer circumference along the middle one third of its namely, one third from either end housed in the piston length. The piston bore on both sides supports this pin bore and the middle one third inside the small end. When through the lubricating oil. The pin oscillates through this is subjected to the bending load from the connecting approximately 10° about its mean position. There are two rod, the middle one third can deform as shown in Figure aspects to be considered for the load distribution, one 4. In Figure 3 the supports on either side are at the along the length of the pin and other along its locations B1 and B2.The two parts of the deformed neutral circumference. Along the circumference, due to the axis (Figure 4) A1 B1 and A2 B2 are assumed to be not lubricating oil pressure, it is periodic with the resultant touching the piston bore. The deformed neutral axis B1C along the line joining small end and the big end and along B2 is not also touching the small end bore of the the width of the connecting rod, with uniform intensity. To connecting rod. meet these two requirements, semi analytical approach This is possible, only when there is adequate clearance can be used (Ramamurti, 2009; Ramamurti and Gupta, available in both the piston bore and the small end of the 1978; Ramamurti and Narayanan, 1989; Quing et al., connecting rod. The Gudgeon pin is treated as a beam 2006; Zienkiewicz, 1991). In this connection, the following carrying uniformly distributed load over one third of its papers that have similar connected applications can be length as shown in Figure 3 and analysis carried out. For cited. this first case, the beam is assumed to be simply Ramamurti and Gupta (1978) have assumed the load supported in locations B1 and B2. Area moment method of a kiln tyre supported by rollers to act over a small arc, (Papov, 1978) is used to compute the deflections and whereas in another paper, Ramamurti and Narayanan axial stress at its salient locations. The beam deflects as (1989) have assumed that the load is transferred along shown in Figure 4. several short arcs for a roller clutch. Quing et al. (2006) have determined the natural frequencies of a shell system by semi analytical approach in finite element Case (ii): Contacts at A1, B1, B2 and A2 method. In this paper, both beam and semi analytical approaches are attempted and results compared. In the second case (Figure 5), the free ends A1 and A2 of 78 J. Mech. Eng. Res.

Figure 4. Deformation of a Gudgeon pin when not touching the piston bore.

Figure 5. Deformation of the Gudgeon pin when it exceeds clearance in the piston bore.

the beam physically touch the piston bore. If the available the locations A1 and A2 .One can, then, calculate the tolerance between the piston bore and the Gudgeon pin deflections and stresses on the pin. is less than the difference in deflection between the ends A1 & B1 or A2 & B2, the Gudgeon pin will touch the piston bore. Semi analytical approach Taking the tolerance available as input one can compute the force F1 experienced by the Gudgeon pin at The beam approach overlooks the role of lubricating oil in Ramamurti et al. 79

1 2  a0  f ( )d  2  0  α being small 1 2  a  f ( ) cos nd n   2 0  1 2  b  f ( )sin nd  n 2   Figure 6. Gudgeon pin surrounded by lubricating oil. 0 

the annular space of the turning pair. This oil will itIf, is onwritten the otheras: hand, if it is assured anti - symmetric, then it can be written as physically lift the pin and transfer the load from the 2  connecting rod to the two sides of the piston bore. This 1 an  f ( )sin nd  corresponds to a dynamic problem of Gudgeon pin   0  supported by the lubricating oil and the load being 2  transferred from the connecting rod through the oil to the 1  piston bore. The connecting rod executes angular b  f ( ) cos nd n    oscillation up to 10° on either side of the mean position 0  (2) around 3000 times a minute. One can examine its role by using the semi analytical approach. In this finite element The resultant of the load must be along the line joining approach, the axial section of the hollow cylinder is the small end and big end of the connecting rod (Figure modelled as a rectangle, with the length equal to the 6). If the load is assumed to act over a semi contact length of the pin and breadth as the difference between angle α on either side of this line (θ=0°) with uniform the inner and outer radii of the pin. intensity f over this arc, then its components along the Since the loading on the Gudgeon pin through the radial direction will be fcosθ and the tangential direction surrounding oil is periodic, it may safely be assumed to fsinθ. Obviously fcos θ is a symmetric periodic function be the sum of a finite number of harmonics. If the and f sin θ is an anti symmetric. When α is extremely pressure variation f(θ) is symmetric Fourier series can be small, this can be treated as a starved Gudgeon pin and written as: when α is , fully lubricated.

1 2  a0  f ( )d  For fcosθ (radial pressure, symmetric), using 2  0  Equation (1)

1 2  a  f ( ) cos nd  n   1 f 2 a   f cosd  sin 0  0 1 2  f  2  a  f cosd  sin 1 0 2   (3)    bn  f ( )sin nd 1 f sin(n 1) sin(n 1)  2   a   f cos cos nd   (n  1) 0  (1) n 1  f sin( n 1) (1)sin( n 1)   a  f cos  cos nd    (n (n1)1) (n 1)  n        (n 1) (n 1)  If, on the other hand, if it is assured anti-symmetric, then f (4) If, on the other hand, if it is assured anti - symmetric, thenWhen it can n  be1, fwrittena1  as ( 2  sin 2) When n 1,a1  (2  sin22) 1 2  when  2, an  f ( )sin nd  when   ,   0  a1  f   a1  f   2 a  a (n 1)  0 1  a 0 a (n n 1)  0  bn  f ( ) cos nd 0 n       0    80 J. Mech. Eng. Res.

 1  f a0  f cosd  sin a0   f cosd  sin 2   2   Figure 7. Bending moment diagram when Contacts are at B1and B2. 1  f sin(n 1) sin(n 1)  a  1 f cos cos nd  f sin(n 1)  sin(n 1) (n  1) an    f cos cos nd    (n 1)  (n 1) (n  1) n        (n 1) (n 1)  f simply supported only at B1 and B2 as shown in Figure 7. When n 1,a1  f (2  sin 2) The bending moment diagram is shown along side. When n 1,a  2 (2  sin 2) (5) 1 2 One can proceed to find out the deflection at C (mid when   , span), A and A (overhanging ends) and the maximum when   , 1 2 a1  f  stress experienced by the Gudgeon pin. Since the beam  is assumed to be symmetric, it is sufficient to calculate a  af (n  1)  0 10 n  the deflections and stress at A and C alone.  1 a 0  an (n  1)  0 Deflection at C is obtained by computing the moment  about B1 of the bending moment diagram between B1 and  (6) C (6) 3 Area  (1/ 24)* wl

For f sinθ, (for circumferential pressure, Distance of C.G of the shaded area from B1= (5/16) ℓ antisymmetric) using Equation (2) Difference in the slope of the tangent between B1and C

3 3 when   ,  B C  (1/ 24)wl *(5/16)l / EI  B1C  (1/ 24)3 wl *(5/16)l / EI   1  (1/ 24)wl *(5/16)l / EI (10) B1C when   , 1 f sin(n 1) sin(n 1)  Since the deflection at B is zero: Since the deflection1 at B1 is zero a0  0,an (n 1)  sin sinnd     Since the deflection at B is zero    Since the deflection at B1 is zero1   1   (n 1) f(fn sin(1) nn11)) sin(sin(nn11))  4 a0  0,an (n 1)  sin sin nd   (7)   4 4 a0  0,an (n 1)   sin sin nd    C(5(/5384/ 384)wl)/wlEI / EI When n 1,     (n 1) CC (n(51/)384 )wl / EI     (n 1) (n 1)  (11) (11) When n 1, Similarly the thedifference difference in the deflection in the deflection between A andbetween C, A1 and C, Whenf n 1, Similarly the difference in the deflection1 between A1 and C, a1  (2  sin 2) 3 3 3 3 2 f   (1/ 24)wl *(213 /16)l / EI  (21/ 384)wl / EI 3 a  (2  sin 2) AA1CC  (1/ 24)wl *(21/16)l / EI  (21/ 384)wl / EI 1 f  A1C  (1/ 24)wl *(21/16)l / EI  (21/ 384 (12))wl / EI (12) whena 2 ,(2  sin 2) (8) 1 1 when2   , a  f Hence the deflection at A1: when1    , a  f   4 1      (1/ 24)wl / EI (13) a0  an (n  1)  0  A1 A1C B1C a10  af n (n  1)  0    a0  an (n  1)  0  Case (ii): Contacts at A1, B1, B2 and A2  (9) The beam has contacts at A1, B1, B2 and A2 as shown in Figures 5 and 8.The reaction forces at A1and A2 can be DETAILS OF ANALYSIS computed by the difference in the displacement from the clearance during manufacture Beam approach The principle of superposition can then be used to combine the effects of two discrete loadings, the first due Case (i) Contacts at B1and B2 to uniform distributed load Case (i) and the second due to a concentrated load F1 Case (ii) (Figure 9). This is shown in Figures 4 and 7. The beam is assumed Considering the reaction forces F1 and using area Ramamurti et al. 81

Figure 8. Force diagram of Case (ii).

Figure 9. BMD due to F1 at A1 and A2.

Figure 10. Deflected shape due to F1 alone.

moment method on the bending moment diagram shown Similarly, the difference in the deflection between A1 and in Figure 10 and Table 1, the difference in the deflection C: between B1and C is:   1/ EI (Fl *l / 2*5l / 4)  (Fl *l / 2*2/3l)  Fl 3 / EI (23/ 24) A1C 1 1 1 (16)

  F l *l / 2*l / 4/ EI Hence    3 B1 C 1 (14) A 1 A  C B  C (14) A C Hence,1/ EI (F1l *l / 2*5l / 4)  (F1l *l / 2*2/3l)  F1l / EI (23/ 24) 3 1 3 3 3 3  (23/ 24 1)F/1EI*l (/FEIl * (l1//28)*F15*ll/ 4/ EI) (F(5l/ 6*)lF/1l2/*EI2/3l)  Fl / EI (23/ 24) Hence, Hence, C  (1/8)F1l / EI A1C 1 1 1   F l *l / 2*l / 4/ EI Hence A1   AC  BC B1 C 1 Hence  (14)   A 1 A  C B  C (15) 3 3 3 3 Hence,  (1/8)F l / EI  (23/ 24(23)F/ 124*)Fl */l 3EI/ EI((11/88)F)F*1l*3 /lEI/EI(5/6)F(5l 3 // EI6)F1l / EI C 1 (15) 1 1 1 (17) (15) 82 J. Mech. Eng. Res.

Table 1. Summary of displacements and stresses.

Description δA δC σ Loading due to UDL of connecting rod (1/24)*wl4/EI (5/384)*wl4/EI M/Z 3 3 Reaction force F1 at the ends (5/6)*F1l /EI (1/8)*F1l /EI M/Z

the Gudgeon pin Gudgeon the

Length of Length

Figure 11. Axial section-semi analytical approach.

If the available clearance between the Gudgeon pin and Semi analytic approach piston bore is c, Using (Equation 17) one can write: ANSYS is used to handle this problem. Symmetric and antisymmetric loading as presented in Equations (3) to 3 (9) are taken as inputs. PLANE 25 (ANSYS) is used for c  (5/ 6)F1l / EI 2-D modeling of axisymmetric (18) structures with

3 nonaxisymmetric loading. The element is defined by c  (5Hence,/HenceF6)F l 3 /1EI 6cEI / 5l three or four nodes having three degrees of freedom per 1 node: translations in the radial, axial and circumferential HenceF  6cEI / 5l 3 directions as shown in Figure 11. The axial section is 1 (19) arrested at the locations of the circlips. The radial

Ramamurti et al. 83

5° Plot area

15°

30°

s of s coefficients 90° 180°

45° Value

Number of Fourier terms

Figure 12. Fourier coefficients for various harmonics.

Table 2. Salient features of the compressor

S/No Description Value 1 Length of the gudgeon pin 60mm 2 Outer diameter/Inner diameter of the pin 13/7 mm 3 Second moment of area I of the pin 1200mm4 4 Section modulus Z of the pin 185 mm3 σ = 600 MPa 5 Material (IS 4432)15C8 of the pin U σy = 400 MPa

6 Width of the con rod (l ) 20 mm 7 Piston bore/stroke 66.7/46 8 Operating speed of the compressor 3000 RPM 9 Maximum air pressure 10 bar

displacements at the outer radius at locations of the in Figure 12 for various harmonics. It can be observed circlips are also assumed to be zero. that convergence is achieved for semi contact angle α Load is uniformly distributed on the Gudgeon pin in the above 30°. For angles less than 30° the number of terms region of the connecting rod and with half its intensity on required increases rapidly. For angles less than 5° even either side in the region of the piston bore (in opposite 100 terms are not sufficient. Hence the semi analytical sense). approach become cumbersome for α<30°. Sum of the deformations and stresses for semi contact angles α of 30, 45, 90 and 180° are calculated for harmonics up to 15. NUMERICAL RESULTS

As a specific example, a reciprocating compressor for air Convergence of results braking system in vehicles with specifications shown in Tables 2 and 3 is taken up. This compressor runs at a For semi contact angle α = 180°, there is only one term (n maximum speed of 3000 rpm and consumes around 10 = 1) (Equation 6). The value is unique. Convergence of hp for compressing the air. The maximum force F the Fourier series by using equations (3) to (6) is studied experienced by the connecting rod due to air pressure 84 J. Mech. Eng. Res.

Table 3. Clearance details of Gudgeon pin

Clearance details (mm) Piston bore Nominal Tolerance Min Max 14.006 0.003 14.003 14.009

Small end of the con rod Nominal Tolerance Min Max 14.008 0.005 14.003 14.013

Gudgeon pin OD Nominal Tolerance Min Max 13.997 0.002 13.995 13.999

Table 4. Summary of results Beam approach:

S/No Description Value Manufacturable lower limit Manufacturable upper limit Comments

Case (i): Contacts at B1 and B2. 1 Deflection at C 0.0033 mm 0.004 mm 0.018 mm Acceptable 2 Deflection at A 0.0105 mm 0.004 mm 0.018 mm Exceeds lower limit

3 σy at C 103MPa Endurance limit 200MPa (50% of yield)for Ni Cr steel Acceptable

Case (ii): Contacts at A1, B1, B2 and A2: 1 Deflection at C 0.002 mm 0.004 mm 0.018 mm Acceptable 2 Deflection at A 0.004 mm 0.004 mm 0.018 mm Acceptable

3 σy at C 80 MPa Endurance limit 200MPa (50% of yield)for Ni Cr steel Acceptable

and inertia force is around 8000 N. Semi analytic approach The information contained in these two tables for this compressor is used to compute the deflection and stress Maximum deflection of around 0.0016 mm as seen from experienced by the Gudgeon pin using the material in Figure 15 experienced by the pin for a semi contact angle Table 2. of 45° indicates that the pin floats in the piston bore and The summary of results obtained is given in Table 4 the bore of the connecting rod (Figure 17). For α>45° the and Figures 13 to 17. Predominant stress by bending maximum deformation is much less. theory will always be σY (axial stress) whereas in semi analytical approach σx (radial), σy (axial) and σz (circumferential) will all be present. Hence Von Mises DISCUSSION OF RESULTS stress is computed for semi contact angle of 45 ° to assess the severity of stress in semi analytic approach. Stress obtained by bending theory is only in the axial From Table 4, it is clear that if the clearance in the direction, its magnitude is higher than corresponding piston bore exceeds 0.0105 mm, the pin will not touch at results obtained by semi analytic approach. Stresses in A1 and A2 (Case i).The maximum stress will be around Case (i) are less than the ones obtained when the 103 MPa. Gudgeon pin, touches the piston bore. When the semi However, if the clearance in the piston bore is less than contact angle of the lubricant is 180° (fully lubricated) the 0.0105 mm, there will be contacts at A1and A2. Then the maximum Von Mises stress is the lowest (around 20 axial stress will come down to 80 MPa (Case ii). Hence it MPa). As the semi contact angle gets reduced, the is sufficient to consider the displacement and stress of maximum stress steadily increases. In the worst case Case (i) alone for the design consideration. Also it shows (assumption of bending theory) it goes up to 103 MPa that the Gudgeon pin will not fail even when the stresses Figure 18 shows the distribution of stresses at mid are in the range of 80 to 103 MPa. section. Beam theory Case (ii) gives rise to a maximum Ramamurti et al. 85

Figure 13. Displacement on Gudgeon based on beam theory- Case (i).

Figure 14. Displacement on Gudgeon pin for α =45°semi analytic approach.

Figure 15. Stress on Gudgeon by beam theory –Case i.

σY of 80 MPa at the outer most fibers. This varies value exceeds 36 MPa. This is understandable since for linearly across the depth of the beam. σX and σZ are not the same intensity of loading in case of semi analytic present. approach the entire cross section participates in load On the other hand in the case of semi analytic sharing. In beam theory the top and bottom fibers approach, σX, σY, and σZ are present everywhere. ( σX is experience maximum σY linearly varying across the depth zero at the free surface of the outer radius).No individual with σx and σZ being zero everywhere. 86 J. Mech. Eng. Res.

Figure 16. Stress on Gudgeon pin for  =45 degree semi analytic approach.

Lubricant oil

Figure 17. Gudgeon pin fully floating in the oil (semi analytic approach).

Conclusion 40 MPa. Alongside is shown the axial stress σY from bending theory Case (i). Figure 19 shows the plot of Von Mises stress for various From the foregoing analysis, it is clear that the semi contact angles. maximum Von Mises stress experienced by the Gudgeon For angles above 30° the stress values do not exceed pin for a well lubricated assembly is unlikely to exceed 40 Ramamurti et al. 87

Figure 18. Stress distribution for beam approach and semi analytic approach.

Stress from beam theory-Case (ii)

Stress (MPa) Stress

Angle in degree

Figure 19. Von Mises Stress on Gudgeon pin for various semi contact angle.

MPa as shown in Figure 19. The material used for of safety around five. This implies that the Gudgeon pin is Gudgeon pin is Nickel-chromium alloy steel whose basically an over designed member which is not endurance limit is above 200 MPa. This provides a factor expected to fail during its operation. Likelihood of 88 J. Mech. Eng. Res.

Gudgeon pin failing in service with this factor of safety is REFERENCES remote. Its failure while the vehicle is running has Brun K, Nored MG, Gernentz RS, Platt JP (2005). Reciprocating disastrous consequences. It has been ascertained from Compressor Valve Plate Life and Performance Analysis, Gas the field data that the end customer is advised to replace Machinery Conference. the piston assembly comprising of piston, piston rings, Papov EP (1978). Mechanics of Materials 2nd Edition, Prentice Hall Gudgeon pin after every 300,000 km of running of a (India), New Delhi. Quing GH, Liu YH, Qui JJ , Mang YG (2006). A semi analytical method vehicle. This standard practice seems to be in line with for the free vibration analysis of a thick double wall shell system. our findings. Finite Element Anal. Des., 42: 837-845. In our opinion, the factor of safety needed for the Ramamurti V (2009). Finite Element Method in Machine Design, Narosa design of Gudgeon pin in the case of diesel engine can Publishing House, New Delhi. Ramamurti V, Gupta LS (1978). Design of kiln tyres, ZKG. 31: 614-618. be much less than what is desirable for reciprocating Ramamurti V, Narayanan NC (1989). Dynamics of roller clutch sleeve, compressor. Since the primary duty of compressor is to Computers and Structures.33: 403-410. compress air, lubricating the Gudgeon pin from an Ramamurti V, Sridhar S, Mithun S , Kumaravel B (2011). Transient additional source is needed. In the case of diesel dynamic analysis of valve stopper used in reciprocating air compressor Proc. INSA .77. engines, since the medium of compression is diesel oil, Venkatesan J, Nagarajan G, Seeniraj RV, Kumar S (2009). the Gudgeon pin getting starved of oil is not present. Mathematical modelling of water cooled automotive air compressor, The foregoing analysis indicates that the choice of Ni Int.J.Engg. Tech., 1: 51-57. th Cr steel for Gudgeon pin has been made to cater to the Zienkiewicz OC (1991).The finite element method, 4 edition, McGraw Hill, London. eventuality of the pin not failing even during the worst scenario of this turning pair totally starved of lubricating oil.

ACKNOWLEDGEMENT

Authors would like to express their gratitude to Ms WABCO-TVS (India) for the encouragement and permission given to report this article in a journal.