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Wet Single Clutch Engagement Behaviors in the Dual-Clutch Transmission System

  • Jaecheol Cho
  • Yongseok Lee
  • Woojung Kim
  • Siyoul Jang
Article
  • 113 Downloads

Abstract

A frictional torque was generated by a lubricated slip contact between a wet clutch pad and a steel separator during a wet clutch engagement. It is necessary to understand the generation of frictional torque to improve the performance of the frictional torque transfer and the durability of the wet clutch system. The analytical modeling of wet clutch torque transfer considers the effects of surface roughness, permeability, the elastic modulus of the frictional material, lubricant viscosity, temperature, etc. Experimental apparatus for wet clutch engagement was designed for the measurement of frictional torque transfer during wet clutch engagement. The experimental results were compared with the analytical results under various operational conditions for the verification of the theoretical analysis to evaluate the performance of the wet clutch system. Some correlations were investigated between the experimental and analytical results. We found that computation by analytical modeling can predict the effects of oil temperature, applied force, and slip speed, as well as engagement period and frictional torque transfer shapes.

Key words

Wet clutch engagement Dual clutch Shudder Torque transfer Modified Reynolds equation 

Nomenclature

A

friction plate area

Ared

ratio of landed area to plate area

d

thickness of friction material

E

Young’s modulus of friction material

g

surface roughness parameter

h

oil film thickness

N

asperity density

Papp

applied pressure on piston

pc

asperity contact pressure

ph

fluid pressure

ri

friction plate of inner radius

ro

friction plate of outer radius

T

total engagement torque

Tc

clutch torque

Tv

viscous torque

uz

exuding velocity of oil

X

parameter between viscosity and temperature

β

asperity tip radius

η

oil viscosity

λs

Stribeck coefficient

μ

friction coefficient

μc

Coulomb friction coefficient

μs

static friction coefficient

ρ

density of fluid

σ

surface roughness of friction material

Φ

permeability of friction material

φ, φs, φf, φfs

flow factors of Patir and Cheng

χ

slip coefficient

ω

clutch relative speed

ωsc

Stribeck coefficient

ω0

initial relative speed

ωc

rotating speed of clutch

ωf

rotating speed of friction plate

ωs

rotating speed of separator plate

ωe

rotating speed of engine

ϑ

fluid temperature

ϑhous

housing temperature

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References

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Copyright information

© The Korean Society of Automotive Engineers and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Jaecheol Cho
    • 1
  • Yongseok Lee
    • 1
  • Woojung Kim
    • 2
  • Siyoul Jang
    • 1
  1. 1.Department of Automotive EngineeringKookmin UniversitySeoulKorea
  2. 2.Development TeamHyundai PowerTech Ltd.GyeonggiKorea

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