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1Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
IntroductionThe simple answer to torque steer:
“Revo” Suspension
• Dipl. – Ing. Michael Frantzen
• Dipl. – Ing. Jasper Bouma
• Dr. – Ing. Wolfgang David
• Dipl. – Ing. Marc Simon
• Dipl. – Ing. Lauri Ohra-aho
Ford Forschungszentrum Aachen
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2Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Index
• „Torque Steer“
• RevoKnuckle
• Results
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3Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Wheel Forces and Moments
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4Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Wheel Forces and Moments
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5Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Wheel Forces and Moments
Focus or Mondeo Knuckle
King pin axis
Wheel center
50 –75 mm
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6Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Disturbing Forces and Moments• No „Torque Steer“ on symmetric conditions
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7Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Technology Description & Scope
„Torque steer“ on asymmetric conditions
Torque Steer Feedback
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8Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Tire Conicity
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9Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Torque Steer Contributors
• Road Conditions(friction and surface)
• Vehicle State(cornering,roll., acc.)
• Weight Distribution (loading)
• Suspension Geometry(kingpin offset, camber,caster, tolerances)
• Tire Quality(Conicity, wear, profile)
• Wheel Geometry (size, uniformity, wheel offset)
• Engine (torque, alignment)
• Differential(friction, self locking effect, Torsen differential)
• Drive Shafts (alignment, length, symmetry)
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10Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Index
• „Torque Steer“
• RevoKnuckle
• Results
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11Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
RevoKnuckle vs. McPhersonRevoKnuckle MacPherson Strut
Tire Contact Patch
King Pin Axis
Wheel Centre Line
Scrub Radius
King Pin Offset
Wheel Centre
Balljoint
New Bearings
Sleeve Joint
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12Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
RevoKnuckle – RevoKnuckle Joint Concepts
Ball Joint
New FFA / ZF Patent Application
Roller Bearing
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13Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Advantages concept• Improved Vehicle Dynamics Performance
- Torque Steer- Wheelfight- Steering Nibble- Brake Judder
• Reduced torquesteer sensitivity to changes in tire size (low aspect ratio) and tire conicity
• Fits to McPherson package, no body changes
• Less expensive than Double Wishbone suspension
• Lighter than Double Wishbone suspension
• Smaller Kingpin offset vs. Double Wishbone suspension : 20-30 vs. 40 mm
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14Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Index
• „Torque Steer“
• RevoKnuckle
• Results
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15Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Kinematics Results
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16Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
FEA Results
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17Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
Driving Results
Results from Driving Evaluation:
• Significant reduction of “torque steer effect”
• Improved vehicle dynamics performance
• No additional error state
• Promising Concept for front driven highperformance vehicles
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18Suspension Projects - The RevoKnuckle
Research & Advanced Engineering Vehicle DynamicsCopyright © Ford Motor Company 2004
End
Questions