Advanced Connecting Rod Designfor Mass Optimization

D i f Li ht W i ht C ti R dDesign for Light Weight Connecting Rod

Alex AntocMAHLE Industries IncMAHLE Industries, Inc.

2010-01-0420 © MAHLE

Connecting Rod Weight Optimization

Contents

Connecting Rod Weight Optimization • Selection Criteria

• Critical Connecting Rod Zones

Pin End Features

Shank and I-beam

Crank End Features

• Advanced Numerical Simulation

• Engine Validation

• Conclusions & Future Work

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Connecting Rod Weight Optimization

Selection Criteria

Selection Criteria• Current Production Rod

Current Production Optimized Design• Current Production Rod

• 36MnVS4BY Forged Steel

• Stepped Pin End

• Bushing less Pin End• Bushing-less Pin End

• MJ8 vs. MJ9

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Connecting Rod Weight Optimization

C iti l ZCritical ZonesPin End

• Strap Thickness• Strap Thickness

• Oil pockets

• Pin Bore Profile

• Surface FinishSurface Finish

• Coating & Clearance

Shank and I-beam• Web Thickness

• Cross Section

• Transition Shape

Crank End• Crank Bore Deformation

• Bolted Joint Optimization

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• Bolted Joint Optimization

© MAHLE

Connecting Rod Weight Optimization

Pin End Features

DOE I & II• Pin Bore Profile

DOE 1&2 Matrix

Pin Bore Profile

Shape & Size

• Surface Finish

Rough vs. Fine Finish Rough vs. Fine Finish

• Forged Oil Pockets

• Clearance

• Pin Bore Coatingg

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Connecting Rod Weight Optimization

Shank and I-beam

Improved Transition Shape• Ogee-arc shape

• 10% Less Crank End Stress at Max. Speed

• 10 m Less Vertical Deformation

• 10 grams lighter

• Less Bearing Stress

• Improved Bearing Fatigue Limit

Minimum Cross Section• Corner Radii

• Web Thickness

• Numerical Simulation

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Connecting Rod Weight Optimization

Crank End Features

Bolted Joint Friction• Tightening Method• Tightening Method

• Clamp Load (Fatigue, Gap Opening)

• Bulging

• Bore DistortionBore Distortion

• Bolt Self Loosening

• Galling/Chatter

Minimum Thread Engagement• Material Selection, Thread Size

• Acceptable Limits (0.7-0.8 x Bolt Diameter)

Crank Bore Roundness• Increased Bearing Stress

• Fatigue & Wear

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g

• Roundness Planes Measurements

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Connecting Rod Weight Optimization

Advanced Numerical Simulation

Structural FEAF ti S f t F t• Fatigue Safety Factor

• Stress Results Criteria

• 95% Survival Rate

10 Million Cycle

Results

• 10 Million Cycle

• Pin Bore Profile

Piston pin Results

• Pressure @ Beginning of Profile

• “Too Aggressive” Profile

• Safety Factors Above

p

Connecting • Safety Factors Above

MAHLE Min. Standards

Bearing

Bearings

rod

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Bearing capBolt

s

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Connecting Rod Weight Optimization

Engine Validation

Tests• Successfully Completed 50 Hours Transient City Cycle Testy p y y

• Pin End Deformation

• Crank Bore Roundness

• Passed Buckling Bench Testing @ 1.4 x Max. Compression Load

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Connecting Rod Weight Optimization

Buckling Limit Experimental Validation

Maximum Engine Loading

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Connecting Rod Weight Optimization

Conclusions

Results• 27% Mass Reduction• 27% Mass Reduction

• Meets MAHLE Min. Safety Factor

• Mass Production Valid

• Ideal for Range Extender/Hybrid Applications• Ideal for Range Extender/Hybrid Applications

• Light Weight Engine Applications

Future Work• Advanced Numerical Simulation

• Full Engine Dynamometer Durability Test

2010-01-042011© MAHLE