iTC – Innovative solutions for torque converters pave the

iTC –

Innovative solutions for torque converters pave

the way into the future

Markus Steinberger

Schaeffler Symposium 2014 Markus Steinberger 1

Hermann Föttinger

1877 - 1945

Father of the torque converter


First TC in mass production

74 Years of TC.

Everything invented?


Rumor has it…

Torque Converter

1940-?


What is a torque converter?

• Launch device

• Clutch

• Torsional vibration isolator

• Continuously variable transmission


The main torus function

Performance

Cost

Customer

success

decided by

Efficiency

• Launch device


Comparison: launch efficiency

Tra

ns.

Engin

e s

peed

Time

Wet or dry clutch

Friction losses

Engin

e

Tra

ns.

Torque converter

Engin

e s

peed

Time

Hydrodynamic

losses

Speed to reach desired launch torque

Torque ratio amplifies

to launch torque

Engin

e

Engin

e s

peed

Time

Hydrodynamic

losses


Comparison: launch efficiency E

ngin

e s

peed

Time

TC has up to TWICE

the efficiency of a

friction clutch

Torque converter

Friction clutch


TC innovation since the last Symposium

•TC as a launch device

•Limited damper performance

New during

Symposium 2010 Goal from Symposium 2010


TC innovation since the last Symposium

• True launch-and-lock

• Superior damper performance

• Cylinder deactivation 6 to 3 cylinders

• More than 30° damper travel and CPA

• TC as a launch device

• Limited damper performance

New during

Symposium 2010

Production during

Symposium 2014


TC innovation - piston

State of the art piston connection Schaeffler piston riveting

• Eliminates riveting connection

• Fewer components

• Saves space


TC innovation - piston

Leaf springs riveted to cover Piston assembled Piston deflected Piston rivet formed


TC innovation - flange

State of the art damper hub Schaeffler net formed flange

• Fewer components

• Reduced weight

• Simplified design


TC innovations

Piston bushing

Pendulum

damper

Schaeffler

friction material


TC innovation recognition

0

10

20

30

40

50

60

2013 2015 2020

Year


Global sales: cars with automatic transmissions

Glo

ball

y s

old

AT

veh

icle

s i

n M

illio

ns

Automatic transmissions with torque converter

Automatic transmissions without torque converter Source: IHS

...Everything that can be invented has been invented.

” “

Charles H. Duell

Commissioner of the

US Patent Office

1899

Innovation



What's next?

The Symposium is about the FUTURE,

not the PAST.


Simple idea

Integrate turbine and piston

TM


iTC function

Clutch release

force

o Pressure separates turbine

and impeller

o Flow enters at stator shaft

o Complete liftoff at very low

release pressure

Clutch disengage TM


iTC function

o Turbine applies towards

impeller

o Flow direction opposite of

typical TC

Clutch apply Apply pressure

Clutch apply

force

TM

Daniel Bernoulli 1700 - 1782


Bernoulli effect and iTC

Low velocity

Lift High velocity,

low pressure

" For an inviscid flow, an increase in the

speed of the fluid occurs simultaneously

with a decrease in pressure."

High oil velocity,

lower pressure

Low oil

velocity,

higher

pressure

Resulting

clutch force

Force from

pressure

difference

Reaction

force


Clutch engagement measurement

0

1000

2000

3000

0.0

0.5

1.0

1.5

2.0

0 5 10 15 20

time in s

sp

eed

in

rp

m

pre

ssu

re in

bar

impeller speed

turbine speed

clutch pressure

smooth

engagement

smooth release


Clutch drag check

Blocked iTC

function with

additional

bearing for

test

1. Run characteristic as iTC

2. Block iTC function

3. Re run test

4. Compare results

Clutch drag comparison

Clutch forced

to stay open TM


Clutch drag measurement To

rqu

e r

ati

o

Speed ratio

K-f

acto

r in

100 r

pm

/Nm

½

Blocked iTC

iTC

0

2

4

6

8

10

12

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0.0 0.2 0.4 0.6 0.8 1.0

K-factor (stiffness)

No difference in

torque converter characteristic

No drag measurable


Note from my old Friend


iTC advantages

TM

More space for damper

(CPA in front wheel drive)

Reduced mass

and inertia

Simpler, more compact

design

No turbine bearing

Impeller thrust washer


Dry weight comparison

iTC design

10.7 kg

Current production

13.1 kg

Damper angle in °

Dam

pe

r to

rqu

e in N

m


iTC advantages

TM

Simplified damper inputs

(modular design)

Markus Steinberger

iTC advantages

TM

Improved clutch stability

due to thrust

No weld behind friction

surface (hot spots)

Improved TC efficiency due

to smaller gap

Blades stiffen

friction surface

Schaeffler Symposium 2014 29


Torque converter evolution

2010 new production

2014 new production

Next generation

TM

Value Innovation


Multi function integrated torque converter

Impeller clutch

Lockup clutch

TM


Design layout

Vent to sump between

bushing and seal

Low to high pressure

controlled

Low or high pressure

not controlled

Impeller clutch

Lockup clutch

TM


Idle disconnect

Sump TC port

Lockup port

Impeller clutch

Open

Lockup clutch

Open

TM

Open


Launch and drive with open TC

Sump TC port

Lockup port

Impeller clutch

Closed Open

Lockup clutch

TM


Lockup clutch at touch point

Sump TC port

Lockup port

Impeller clutch

Closed Open

Lockup clutch

TM

Open Closed


Lockup clutch applied

Sump TC port

Lockup port

Impeller clutch

Closed

Lockup clutch

TM

Closed


Lockup clutch at touch point

Sump TC port

Lockup port

Impeller clutch

Closed Open

Lockup clutch

TM


TC mode

Sump TC port

Lockup port

Impeller clutch

Closed Open

Lockup clutch

TM

Closed


Idle disconnect

Impeller clutch

Open

Lockup clutch

Open

TM


mTC benefits

TM

o Overcome turbo lag of turbo

charged engines

o Reduce start drag of small

engines

mTC use


iTC modularity

Damper technology

Multi fu

nctio

n te

chnolo

gy

TM

TM


o Reduced space, mass and inertia

o Enables CPA in FWD package

o More TC functionality possible

(variable K-factor, idle disconnect, …)

o Modern automatic transmissions

o Front and rear wheel drive

Product Focus

iTC benefits

...Everything that can be invented has been invented.

” ‟

Charles H. Duell

Commissioner of the

US Patent Office

1899

iTC


...Everything that can be invented

has been invented.

” ‟

Documents

iTC – Innovative solutions for torque converters pave the