Friction and Wear Bench Tests of Different Engine Liner Surface Finishes

Friction and Wear Bench Tests of Different Engine Liner Surface Finishes 34 th Leeds-Lyon Symposium on Tribology 2007 Eduardo Tomanik MAHLE Brazil Tech Center Tomanik E. Friction and wear bench tests of different engine liner surface finishes.

Friction and Wear Bench Tests of Different Engine Liner Surface Finishes Index 1- Introduction 2- Studied Liner Finishes 3- Reciprocating Friction Tests 4- Reciprocating Wear Tests 5- Discussion and Conclusions 2/20 01-

INTRODUCTION Different engine bore finishes have been investigated and introduced in production due to the potential of minimizing - Friction, - Wear, - Lube Oil Consumption Smedley, Tian, Wong, 2004 Experimental Friction Coef. 0.12 0.10 0.08 0.06 0.04 0.02 Plateau Honing Slide Honing 3/20 0.00 01-0 50 100 150 200 250 300 350 400 Speed (rpm) Tomanik, 2006

Studied Liner Finishes HDD ø131 mm, alloyed perlitic grey cast iron Slide Rk 0.5-1.2 Slide Rk 0.5-0.9 UV Laser Laser 1mm Laser 3mm Non-Laser Region 5/20 Rq 0.74 0.69 0.41 0.85 0.93 0.18 Roughness (µm) Rpk 0.17 0.13 0.66 0.23 0.17 0.20 Bearing Rate (um) 1.5 1.0 0.5 0.0-0.5-1.0-1.5-2.0-2.5 Rk 0.70 0.54 0.60 0.64 0.38 0.32 Slide 0.5-1.2 Rvk 1.68 1.69 0.60 1.58 2.00 0.28 Slide 0.5-0.9 UV Laser 3 mm Rpk Rk Rvk Laser 1mm Laser 3mm Non-Laser 01- Region

Studied Liner Finishes HDD ø131 mm, alloyed perlitic grey cast iron Bearing Rate (um) 1.5 1.0 0.5 0.0-0.5-1.0-1.5-2.0 Rpk Rk Rvk Slide -2.5 Slide 0.5-1.2 Slide 0.5-0.9 UV Laser Laser 1mm Laser 3mm Non-Laser Region UV Laser Laser Non-Laser region 6/20 01-

Friction Tests 50 N UMT Reciprocating Test, 10 mm stroke Applied load: 50, 100 N. Speed from 25 to 375 rpm Flooded with SAE30 Texaco Regal oil PVD 3mm top rings Load Ring piece Friction Coefficient 0.14 0.12 0.10 0.08 0.06 0.04 Slide 0.5-1.2 Slide 0.5-0.9 UV Laser Laser 1mm Laser 3mm Non-Laser Region S t ro ke liner 2 5. 4 m m 9/20 0.02 0.00 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Speed/Load [rpm/n] 01-

Wear Tests Friction along Test UMT Reciprocating Test 4 hour test P = 360 N (P= 12 MPa), 900 rpm Flooded with SAE30 Texaco Regal oil doped with hard particles to accelerate ring wear PVD top rings Friction Coef 0.10 0.08 0.06 0.04 Slide 0.5-1.2 Slide 0.5-0.9 UV Laser Laser 1mm Laser 3mm Non-Laser region 0.02 0.00 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 12/20 T(h) 01-

Wear Tests Ring and Liner Wear UMT Reciprocating Test 4 hour test Flooded with SAE30 Texaco Regal oil doped with hard particles to accelerate ring wear PVD top rings Load Ring piece Ring S t ro ke liner m m 2 5. 4 2 µm 8 6 Wear (µm) 4 µm Liner After Test Liner Wear Ring (um) 4 2 0-2 -4 Slide 0.5-1.2 Slide 0.5-0.9 UV Laser Laser 1mm Laser 3mm Non-Laser 13/20 01-

Modelling HDD ø128 mm, alloyed perlitic grey cast iron Depth (um) 1.5 1.0 0.5 0.0-0.5-1.0-1.5-2.0-2.5-3.0-3.5 Slide Plateau Rpk Rk Rvk Greenwood surface parameters, summit asperity: Z S mean height [µm] σ height standard deviation [µm] β mean radius [µm] η density [m-2] summit height distribution z S surface height distribution SH PH Rq 0.43 1.00 Rpk 0.17 0.26 Rk 0.47 0.99 Rvk 1.37 1.79 Z S 0.33 0.72 σ 0.25 0.40 β 13.1 12.5 η (10 9 ) 35 28 Patir & Cheng Flow Factors 15/20 MIT ring simulation adapted code assumed fully flooded conditions Profile and Surface parameters calculated from the experimental pieces dry friction coeff. assumed = 0.11 L Sp P = 1 bar b T = 30 C P = 1 bar h 01-

Experimental vs. Predicted Friction Plateau Honing 0.12 0.10 0.08 0.06 Exp Model Friction Coefficient 0.04 0.02 0.00-0.020.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0-0.04-0.06-0.08-0.10-0.12 Speed/Load [rpm/n] 16/20 Ring profile is non-symmetric, friction varies with direction. Negative values are only due to the force sensor. 01-

Experimental vs. Predicted Friction Slide Honing 0.12 0.10 0.08 Exp Model 0.06 Friction Coefficient 0.04 0.02 0.00-0.020.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0-0.04-0.06-0.08-0.10-0.12 Speed/Load [rpm/n] 17/20 Ring profile is non-symmetric, friction varies with direction. Negative values are only due to the force sensor. 01-

Predicted Oil Film Thickness / Asperity Contact Plateau Slide 1.4 Calculated Oil Film Thickness HDD engine, 1800 rpm, 25% load at 0.80 µm A C /A 0 = 21 % V Oil /A 0 = 0.84 µm Oil Film (µm) 1.2 1.0 0.8 0.6 0.4 0.2 Plateau Slide 0.0-360 -180 0 180 360 Crank Angle (deg) at 0.80 µm A C /A 0 = 0.3 % V Oil /A 0 = 0.80 µm at 0.30 µm A C /A 0 = 53 % V Oil /A 0 = 0.53 µm 18/20 Calculated Results show that the Smoother finishing presents: lower asperity contact pressure lower friction & wear lower oil volumes potential for lower LOC at 0.15 µm A C /A 0 = 32 % V Oil /A 0 = 0.19 µm 01-

Conclusions -- With increase of speed, the smoother surfaces tend to enter first in hydrodynamic regime. The laser 3 mm and the smooth non-laser region showed significant lower friction. But only roughness can not explain the different friction. -- In the wear tests, friction reduced along the test due the break-in. In general, friction along the wear test followed the friction test ranking. -- Effect of surface finish was not significant on the measured liner wear. For the ring wear, the smoother variants caused lower wear. -- Under engine operation, the structured laser spots may combine the lower friction advantage of the very smooth finish along the stroke and the oil reservoirs on the spotted region. 19/20 01-