Division Mobile Working MachineryProf. Dr.-Ing. Dr. h.c. K.-Th. Renius c/oInstitute of Automotive EngineeringProf. Dr.-Ing. B. HeißingTechnische Universität München

Control and Operating Behavior ofContinuously Variable Chain Transmissions

2004 International Continuously Variable and Hybrid Transmission CongressSeptember 23-25, 2004

Roland Mölle

Mölle

2004

Introduction – Chain-CVT

Summary

Clamping Systems

Ratio Control Design during Range Shifts in Autarkic Hybrid

Expanded Control Layout for Universal Use in Chain Variator Applications

Presentation Outline

Mölle

2004Introduction

Chain

Hydro-Mechanical Torque Sensor

Secondary Pulley

Primary Pulley

PIV Chain Converter

Mölle

2004

Typical CVT chain of amodern passenger car:Audi multitronicTorque Capacity up to 300 NmNominal Power 162 kW (V6-3.0)

Pull type Chain in Audi/LuK CVT

Mölle

2004

Brand Model Engine Maximum Torque

Transmission ratio (Variator, Overall) Type of Variator

Audi A4 4-Zyl., 2,0 l, 96 kW 195 Nm ? Pull Type Chain

Audi A4 6-Zyl., 3,0 l, 162 kW 300 Nm ? Pull Type Chain

Audi A6 4-Zyl., 1,8 l, 110 kW 210 Nm 2,4 - 0,4; 6,0 Pull Type Chain

Audi A6 6-Zyl., 2,4 l, 121 kW 230 Nm 2,4 - 0,4; 6,0 Pull Type Chain

Audi A6 6-Zyl., 2,8 l, 142 kW 280 Nm 2,4 - 0,4; 5,3 Pull Type Chain

Daewoo Matiz 3-Zyl., 0,8 l, 38 kW 69 Nm ? Push Belt

Daihatsu Cuore 3-Zyl., 0,7 l, 43 kW 64 Nm 2,27 - 0,55; 6,77 Push Belt

Fiat Punto 4-Zyl., 1,2 l, 59 kW 114 Nm 2,43 - 0,44; 5,25 Push Belt

Honda Logo 4-Zyl., 1,3 l, 48 kW 108 Nm 2,47 - 0,45; 6,36 Push Belt

Honda Insight 3-Zyl., 1,0 l, 50 kW 91 Nm 2,44 - 0,41; 5,69 Push Belt

Honda Civic 4-Zyl., 1,4 l, 66 kW 130 Nm 2,47 - 0,45; 5,81 Push Belt

Honda Civic 4-Zyl., 1,6 l, 81 kW 152 Nm 2,47 - 0,45; 5,81 Push Belt

Honda Civic 4-Zyl., 1,7 l, 85 kW 149 Nm 2,47 - 0,45; 5,81 Push Belt

Honda Capa 4-Zyl., 1,5 l, 72 kW 133 Nm 2,47 - 0,45; 6,34 Push Belt

Honda HR-V 4-Zyl., 1,6 l, 77 kW 135 Nm 2,47 - 0,45; 6,88 Push Belt

Honda HR-V 4-Zyl., 1,6 l, 92 kW 144 Nm 2,47 - 0,45; 6,88 Push Belt

Mazda 121 4-Zyl., 1,2 l, 55 kW 110 Nm 3,84 - 0,66; 3,84 Push Belt

MG MGF 4-Zyl., 1,8 l, 88 kW 165 Nm 2,42 - 0,52; 4,05 Push Belt

CVT Passenger Cars (worldwide, 2001)

Mölle

2004

Brand Model Engine Maximum Torque

Transmission ratio (Variator, Overall) Type of Variator

Mini Cooper 4-Zyl., 1,6 l, 85 kW 149 Nm ? Push Belt

Mitsubishi Lancer Cedia 4-Zyl., 1,8 l, 96 kW 177 Nm 2,32 - 0,45; 5,22 Push Belt

Nissan Micra/March 4-Zyl., 1,0 l, 44 kW 80 Nm 2,43 - 0,44; 6,3 Push Belt

Nissan Micra/March 4-Zyl., 1,4 l, 60 kW 108 Nm 2,43 - 0,44; 5,25 Push Belt

Nissan Cube 4-Zyl., 1,3 l, 63 kW 120 Nm 2,43 - 0,44; 5,24 Push Belt

Nissan Bluebird 4-Zyl., 2,0 l, 110 kW 200 Nm ? Push Belt

Nissan Almera Tino 4-Zyl., 2,0 l, 100 kW 175 Nm 2,33 - 0,43; 5,47 Push Belt

Nissan Primera 4-Zyl., 2,0 l, 103 kW 181 Nm 2,33 - 0,43; 4,18 Push Belt

Nissan Primera '02 4-Zyl., 2,0 l, 110 kW 200 Nm 2,33 - 0,43; 5,47 Push Belt

Nissan Primera '02 4-Zyl., 2,0 l, 125 kW 245 Nm 2,1 - 0,43; 5,47 Push Belt

Nissan Prairie/Liberty 4-Zyl., 2,0 l, 103 kW 186 Nm 2,33 - 0,43; 5,47 Push Belt

Nissan Serena 4-Zyl., 2,0 l, 107 kW 186 Nm 2,33 - 0,43; 5,74 Push Belt

Nissan Cedric/Gloria 6-Zyl., 3,0 l, 206 kW 388 Nm 2,86 - 0,66; 3,69 Half Toroid

Rover R45 4-Zyl., 1,8 l, 86 kW 160 Nm 2,42 - 0,44; 5,76 Push Belt

Subaru Pleo 4-Zyl., 0,7 l, 33 kW 56 Nm 2,43 - 0,44; 4,67 Push Belt

Suzuki Alto/Kei 3-Zyl., 0,7 l, 34 kW 57 Nm 2,42 - 0,55; 6,77 Push Belt

Toyota Opa 4-Zyl., 2,0 l, 112 kW 200 Nm 2,4 - 0,43; 5,18 Push Belt

CVT Passenger Cars (worldwide, 2001)

Mölle

2004

Introduction – Chain-CVT

Summary

Clamping Systems

Control Design for Range Shifts in Autarkic Hybrid

Expanded Control Layout for Universal Use in Chain Variator Applications

Presentation Outline

Mölle

2004Constant Pressure System

Oil flow on demand

Torque information supplied by engine controller: Poor dynamics and limited accuracy

Need for high over clamping for security reasons or additional measures

Oil flow always at maximum pressure level

Main Advantage:

Disadvantages:n CVT2

n CVT1

Up

Up

Pulley 1

Pulley 2

Constant PressureOil Supply

PressureTransducer

DirectionalControl Valve

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2004

M d

M d

Constant FlowOil supply

Pulley 1

Pulley 2

HydraulicControl Unit

Four Edges

Torque Sensor

ActuatorSpeed Ratio Control

Pressure DifferentialValve

Line PressureValve

Constant Oil Flow System (PIV)

Clamping pressures are automatically achieved without superior control

High dynamically set clamping pressures due to the “pump function”

Clamping pressure and speed ratio control independent

Permanent, constant oil flow required

Advantages:

Main Disadvantage:

Spool Valve

Mölle

2004

TrM d

A FA F

F u

F ax

F p

s F

jF

A A

A -A

b F

Conventional Torque Sensor(System PIV)

Torque sensor pressure – proportional to torque at the shaft

Characteristics:

sF (axial movement of sensorplate)

Movable sensor plate

Additional “pump function” at high torque gradients

Mölle

2004

Characteristic Curve of Actuator in Conventional PIV Clamping Systems

0

10

20

40

-1,5 -1 -0,5 0 0,5 1,5

Slide valve travel

Pre

ssur

e

bar

mm

Pcyl1 Pcyl2

pTorque Pump

pCYL1 pCYL2

p TORQUE pPUMP

Tor

que

0

100

200

Nm

400

Mölle

2004

Introduction – Chain-CVT

Summary

Clamping Systems

Control Design for Range Shifts in Autarkic Hybrid

Expanded Control Layout for Universal Use in Chain Variator Applications

Presentation Outline

Mölle

2004

L1

L2 K1

K2A

B

C

D

E

F

A: input shaftB: shaft of CVTC: shaft of CVTD: output shaftE: differential gearF: electric engine

Driveline of the Autarkic Hybrid

The Autarkic Hybrid

Opel Astra Caravan

60 kW Diesel engine

10 kW electric motor (120V)

i2-CVT gearbox

Range shift in Autarkic Hybrid raised the need for improved speed ratio control:

Extremely high torque gradients during range shift(CVT engaged vs. disengaged)

Error signal <0,002 required

Mölle

2004CVT Controller, Variable in Structure

LinearC ontro lle r

C V Tsetpoin t

Error signal limit positive high

Error signal limit positive low

Error signal limit negative low

Error signal limit negative highPI-Control

PD-Control

Sys

tem

dev

iatio

n

Absolute value of deviationAlgebraic sign of deviation

Selection of control parameters:

0

Value of control variableVariation of param. (gain scheduling):

Mölle

2004Influence of Disturbance Variables

Ratio ofclamping forces

FAn

FAb

=

FAb=pAb.Az

FAn=pAn.Az

pAn

Az

Az

pAb

Main disturbancevariables:• Torque• Speed Ratio

... lead to a change in required -ratio for steady state operation

Mölle

2004Extension of the Speed Ratio Controller

LinearC ontro lle r

C V Tsetpoin t

Problem:

Improved control system is needed for speed ratio control at SYN (i=0,458) during range shift.

Solution:

Disturbance feedforward (torque)

Mölle

2004

-30

-20

-10

0

20

0 5 10 15 20 30

%

barbar

2500 1/m in3000 1/m in

1000 1/m in1500 1/m in2000 1/m in

Slid

e va

lve

trav

el

Torque sensor pressure

-50

-40

-30

-20

-10

0

20

0 5 10 15 20 30Torque sensor pressure

Slid

e va

lve

trav

el

bar

V2

V1

LinearC ontro lle r

C V Tsetpoin t

D isturbancefeedfo rw ard

T, n

Extension of the Speed Ratio Controller

Mölle

2004Results and further Aims

The taken measures resulted in a significant improvement of the quality of speed ratio control and reliability of range shifts.

Apply same principles to the CVT controller for universal use:

Regard to further disturbance variables

Improved control over the whole spreading range(improvements in quality, efficiency etc.)

Enable different control strategies:ratio based strategies (e.g. ground speed pto) vs.di/dt control (passenger car / transportation work)

Mölle

2004

Introduction – Chain-CVT

Summary

Clamping Systems

Control Design for Range Shifts in Autarkic Hybrid

Expanded Control Layout for Universal Use in Chain Variator Applications

Presentation Outline

Mölle

2004

Further disturbance variables:• Speed (rotating hydraulic cylinder)• Spring (basic clamping force)

Characteristic -map

Disturbance Variables

Algebraic compensation

Main disturbance variables torque and speed ratio lead to:

Pulley Misalignment, shaft deflection, pulley distortion, …

… change in clamping force ratio

Mölle

2004

setpointCVT

Extension of the Control Structure

Distrubancefeedforward

DisturbanceVariables

actualvalue

-map

Mathematic

Compensation

E=mc2

LinearController

Mölle

2004

setpointCVT

Adaptation of -map

Distrubancefeedforward

DisturbanceVariables

actualvalue

Adaptation

-map

Mathematic

Compensation

E=mc2

Steady state(T, n, manipulated var.)

…

Prerequisites for adaptation:

background task (duration ?)

constant task time (e.g. 5ms)

LinearController

Question:

Where to get the -map from ?Output of Linear Controller supposed to

be Zero in steady state!

Mölle

2004Adaptation Law

Weighting functions:• Gauss• Cone • ...

Adaptation of the sampling points:

Value of the manipulated variable from linear controllerx weighting factor.

Mölle

2004

START

Visualization and Discussion of the Adaptation Process

Mölle

2004CVT in Drive Train Configuration

J1

T1

T2

i

ω1

ω2di/dtJ2

Power demand leads to desired engine speed.

New engine speed is achieved by changing the CVT’s speed ratio i.

Change in speed ratio di/dt affects the available torque at the wheel T2!

Controlling the rate of speed ratio change is favorable

Mölle

2004

Control of the Rate ofSpeed Ratio Change di/dt

CVT

Distrubancefeedforward

DisturbanceVariables

-map

Mathematic

Compensation

E=mc2

Modification of thecontrol structure: Adaptation

LinearController

Stop Adaptation Process

Delete Feedback Loop

Replace Controller

f(di/dt,n,geometry)

setpoint

di/dt

pdyndi/dtsetpoint

speed ratio

speed

ratio

Mölle

2004

Control of the Rate ofSpeed Ratio Change di/dt

pdyn = ds/dt / ( ACYL·D )

Axial pulley speedds/dt = f ( di/dt, geometry )

Damping coefficientD = f ( speed… )

* ü = 1/i

Mölle

2004

Measured Results of the Control ofSpeed Ratio Change ds/dt

Mölle

2004

Introduction – Chain-CVT

Summary

Clamping Systems

Control Design for Range Shifts in Autarkic Hybrid

Expanded Control Layout for Universal Use in Chain Variator Applications

Presentation Outline

Mölle

2004Summary

Quality of speed ratio control was significantly improved

The control structure was implemented using a RCP-system running under Matlab/Simulink (xPCTarget)

and is currently running on a test rig

For use in tractor applications it was also implemented on a typical electronic control unit (C167) both manually and using code generation (dSpaceTargetLink 2.0)

Gathered -maps can be used for different purposes (scientific work, onboard diagnostic purposes etc.)

Further optimization possible (improved di/dt, -max)

Division Mobile Working MachineryProf. Dr.-Ing. Dr. h.c. K.-Th. Renius c/oInstitute of Automotive EngineeringProf. Dr.-Ing. B. HeißingTechnische Universität München

Control and Operating Behavior ofContinuously Variable Chain Transmissions

2004 International Continuously Variable and Hybrid Transmission CongressSeptember 23-25, 2004

Roland Mölle

Mölle

2004