modeling of clutch housing and facing temperature for ... of clutch housing and facing temperature...

1Feb 6, 2017Copyright © 2017 Mahindra & Mahindra Ltd. All rights reserved. India GT-SUITE Conference 2017, Pune

Modeling of Clutch Housing and Facing Temperature for Estimating Clutch Life of

a Manual Transmission Vehicle

Presented by:

P Srinivasan

Co-Authors:

Dr. Saravanan Muthiah

Vehicle Performance Simulation (VPS-COE)

Powertrain Division (PTD)

Mahindra & Mahindra Ltd


Introduction & Motivation

Poor clutch life is a major issue for some vehicle models.

Clutch overheating is theprimary cause for clutchfailure. The reasons include:

Vehicle Overloading

Heavy Traffic

Riding of Clutch Pedal

Incorrect Gear

Selection

Poor Low end torque


Impact of Clutch Temperature:

Temp

Friction

Torque Transfer

Slip

Safe Zone

High Clutch Wear

Clutch Failure


Impact of Clutch Temperature:

High Wear Rate

Source:Technical Handbook,Valeo TransmissionSystems.


Objective:

Estimate temperature rise onclutch facing & clutch housing.

Optimize Clutch Design at an earlystage of Product Development inconjunction with supplier provideddata (facing temperature vs wearratio) for different clutch materials.

Objective & Scope of the Study


ResistanceTorque (𝝉𝒅𝒓𝒗)

Transmitting torquefrom the engine (T)

HeatEnergyGenerated

Heats UpFrictionalComponents

Heats Up AirWithin ClutchHousing

Thermal EnergyDissipated Energy

Theory Behind the Simulation Model

Clutch Slip

Drive Torque

HousingDissipates SomeHeat to Ambient

Convection

Torque Loss

Clutch Housing

GBEngine

CSC(T Avg)

T High

T Low


𝐓. 𝐅𝐎𝐒 = 𝑵𝒇. 𝑹𝒎. µ. 𝑭𝒂LuGre Friction Model

This friction model is based on the

idea of intermeshing bristles that

transmit the friction load between

contacting bodies. The bristle

model captures micro slip and

also the drop in friction as the

sliding speed is increased.


T = Transmitting torque from the engine

FOS = Factor of safety is 1.3

𝑁𝑓 = Number of sliding surfaces

(Single clutch=2; Twin clutch=4)

𝑅𝑚 = Clutch mean or effective radius

µ = Friction coefficient of the clutch linings

𝐹𝑎 = Clamping load

Clamp Load – The load exerted by the diaphragm to clampthe clutch disc between pressure plate & flywheel

Step (1): The torque that a clutch can transfer from an engine isobtained by the equation below:


𝝉𝒅𝒓𝒗

= 𝑰𝒕𝒓𝒂𝒏𝒔1 +𝑰𝒕𝒓𝒂𝒏𝒔2

𝑹𝒕2 +

𝑰𝒅𝒔𝒉

𝑹𝒕2 + +

𝑰𝒂𝒙𝒍

𝑹𝒅2𝑹𝒕

2 +𝑴𝒗𝒆𝒉𝒓𝒘𝒉𝒍

2

𝑹𝒅2𝑹𝒕

2

𝒅𝝎𝒅𝒓𝒗

𝒅𝒕

+𝑭𝒂𝒆𝒓 + 𝑭𝒓𝒐𝒍 + 𝑭𝒈𝒓𝒅

𝑹𝒅𝑹𝒕𝒓𝒘𝒉𝒍


𝝉𝒅𝒓𝒗 = Resistance torque

Itrans = Transmission inertia

Idsh = Driveshaft inertia

Iaxl = Axle inertia

Mveh = Vehicle mass

rwhl = Wheel dynamic rolling radius

𝑑𝜔𝑑𝑟𝑣 = Angular speed of input shaft

𝑅t = Transmission ratio

𝑅d = Final drive ratio

𝐹𝑎𝑒𝑟 = Aerodynamic resistance force

𝐹𝑟𝑜𝑙 = Rolling resistance force

𝐹𝑔𝑟𝑎𝑑 = Gradient resistance force

Step (2): Resistance torque generated by the driveline & vehicleduring vehicle launch is obtained by:


Step (3): Clutch energy is calculated by using the below equation

𝑬 = 𝒕𝒊

𝒕𝒄

∆𝑻𝒕 . ∆ 𝝎𝒕 . 𝒅𝒕E = Clutch energy; ti = Initial temperature

tc = Critical temperature; ∆Tt = Torque range

∆ωt = Angular speed bet′n engine & gearbox

𝐷 = Outer diameter of clutch; d = Inner diameter of clutch 𝑷𝒐𝒘𝒆𝒓 =𝑬

𝒕


Due to clutch slip, heatenergy is generatedwhich increases theclutch facingtemperature.

The dissipated energyalso heats the air withinthe clutch housing, whichcan be measured easilyusing thermocouple.

Step (4): Clutch temperature is calc. by using thermal conductance

𝑻𝒉𝒆𝒓𝒎𝒂𝒍 𝑪𝒐𝒏𝒅𝒖𝒄𝒕𝒂𝒏𝒄𝒆 =𝑾

𝒎2 . 𝑲𝑨𝒓𝒆𝒂 =

𝝅 (𝑫2 − 𝒅2

4 . 𝑵𝒇



𝑻𝒐𝒕𝒂𝒍 𝒗𝒐𝒍𝒖𝒎𝒆 𝒘𝒐𝒓𝒏 𝒐𝒇𝒇 𝒎𝒎3 = 𝑭𝒓𝒊𝒄𝒕𝒊𝒐𝒏 𝒆𝒏𝒆𝒓𝒈𝒚 𝒅𝒊𝒔𝒔𝒊𝒑𝒂𝒕𝒊𝒐𝒏 𝑴𝑱 .𝑾𝒆𝒂𝒓 𝒓𝒂𝒕𝒆𝒎𝒎3

𝑴𝑱

Step (5): Clutch wear is calculated by using the below equation:

Sample


Step (7): Finally, Clutch life is obtained by using below equation


𝑵𝒐 𝒐𝒇 𝒄𝒚𝒄𝒍𝒆𝒔 =𝑪𝒍𝒖𝒕𝒄𝒉 𝒖𝒔𝒆𝒇𝒖𝒍 𝒗𝒐𝒍𝒖𝒎𝒆

𝑻𝒐𝒕𝒂𝒍 𝒗𝒐𝒍𝒖𝒎𝒆 𝒘𝒐𝒓𝒏 𝒐𝒇𝒇

𝑪𝒍𝒖𝒕𝒄𝒉 𝒍𝒊𝒇𝒆 𝒌𝒎= 𝑫𝒓𝒊𝒗𝒆 𝒄𝒚𝒄𝒍𝒆 𝒅𝒊𝒔𝒕𝒂𝒏𝒄𝒆 𝒌𝒎 . 𝑵𝒐 𝒐𝒇 𝒄𝒚𝒄𝒍𝒆𝒔

Step (6): Clutch useful volume is calculated by using below equation

𝑪𝒍𝒖𝒕𝒄𝒉 𝒖𝒔𝒆𝒇𝒖𝒍 𝒗𝒐𝒍𝒖𝒎𝒆 𝒎𝒎3

= 𝑪𝒍𝒖𝒕𝒄𝒉 𝒂𝒓𝒆𝒂 𝒎𝒎2 . 𝑪𝒍𝒖𝒕𝒄𝒉 𝒖𝒔𝒆𝒇𝒖𝒍 𝒕𝒉𝒊𝒄𝒌𝒏𝒆𝒔𝒔 𝒎𝒎


Input Data Requirements


Clutch Drive Cycle Input Data

• Drive cycle data (~27 km) was collected in Chennai city during peak traffic

• ~ 30 repeated launches in 1200 sec was observed (~1.2 km), which means every 40 sec/launch occurs.


Clutch Thermal Simulation Model


Clutch Thermal Simulation Model

Conduction

Clutch Housing Ambient

Convection

Convection


Simulation Model


Passenger Vehicle(SUV) was used fortesting.

The thermocouplewas inserted inClutch housing &temperature wasmeasured.

Test data collectionwas started oncethe air within theclutch housingreached 80 deg. C.

Vehicle Testing

Cross Section View of Clutch

Clutch Housing

GBEngine


Vehicle/Engine Speed Comparisons


Clutch Temperature Simulation Results

• Simulation model predicts both clutch facing and housingtemperatures

• Out of which the clutch housing temperature can be measuredeasily during testing


Simulation Vs Test Results

• Clutch temperature simulation model shows an excellentcorrelation (> 90%) with the test results.


Final Drive Ratio

Tyre Size

Vehicle Weight

Road Grade

Sensitivity Analysis Results

Better Clutch LifeBetter Launch NVHBetter In-Gear AccelerationBetter Gradeability

Better FEBetter High Speed NVHBetter In-Gear Elasticity

Right Trade-Off


Clutch Life Estimation (Example)

Cumulative Wear (mm3) 170

Clutch Useful Volume (mm3) 43982

Number of Cycles 258

Cycle Distance (km) 0.71

Total Distance (km) 183


Different Facing Material

Optimize the Target Performance based on

Benchmark

Optimize the Clutch Design

Applications


Clutch overheating is the primary cause for clutch failure.

By using 1-D thermal modeling, clutch facing & housingtemperature are simulated.

Simulation results show an excellent correlation (> 90%)with the test data.

FDR has a huge impact on Clutch wear, FE, Drivability & NVH.Hence, doing a right trade-off is very critical at an earlydesign stage.

Conclusion


T. K. Garrett, K. Newton & W. Steeds., The Motor Vehicle, 13th Edition, ISBN 07506-4449-4: 750-759, 2001.

Bosch Automotive Handbook, 6th Edition, SAE, Robert Bosch GmbH, ISBN 0-7680-1513-8, 2004.

Virendra Kumar, Gopal Sahu, Prakash, Ritesh, Shailendra, “Review on Wear Analysis of Different Types of Clutch Material,” International Journal of Research in Advent Technology, E-ISSN: 2321-9637, 2015.

Shaohua Sun, Yulong Lei, Yao Fu, Cheng Yang and ShunBo Li, “Analysis of Thermal Load for Dry Clutch under the Frequent Launching Condition,” SAE Technical Paper 2013-01-0814.

K.C. Lathiya, N.P. Badola, C.L. Unhad, B.D. Dhamecha, “A Literature Review on Failure in Single Plate Clutch System,” International Journal for Scientific Research & Development, ISSN: 2321-0613, 2014.

Technical Handbook, Valeo Transmission Systems.

GT-SUITE User Guide, GT-ISE v2016.

Ricardo Victorino Coelho, Tulio Gustavo Lima, “Clutch 430 Heavy Duty,” SAE Technical Paper 2011-36-0257.

References


GT Support Team (North America) / ESI-Group (Pune)

Clutch Team

Engine Calibration Team

Acknowledgements


Thank you for your attention !

modeling of clutch housing and facing temperature for ... of clutch housing and facing temperature...

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