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

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2004 International Continuously Variable and
Hybrid Transmission Congress September 23-25, 2004
Control and Operating Behavior ofContinuously
Variable Chain Transmissions
Roland Mölle
2

• Introduction Chain-CVT

• Clamping Systems

• Ratio Control Design during Range Shifts in
  Autarkic Hybrid

• Expanded Control Layout for Universal Use in
  Chain Variator Applications

• Summary

Presentation Outline
3

• PIV Chain Converter

Chain
Secondary Pulley
Primary Pulley
Hydro-Mechanical Torque Sensor
Introduction
4
Typical CVT chain of amodern passenger carAudi
multitronicTorque Capacity up to 300 NmNominal
Power 162 kW (V6-3.0)
Pull type Chain in Audi/LuK CVT
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CVT Passenger Cars (worldwide, 2001)
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CVT Passenger Cars (worldwide, 2001)
7

• Introduction Chain-CVT

• Clamping Systems

• Control Design for Range Shifts in Autarkic
  Hybrid

• Expanded Control Layout for Universal Use in
  Chain Variator Applications

• Summary

Presentation Outline
8
Main Advantage
Pressure

• Oil flow on demand

Transducer
Pulley 1
Disadvantages

• 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

Pulley 2
Directional
Control Valve
Constant Pressure
Oil Supply
Constant Pressure System
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Advantages
Torque

• 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

Sensor
Pulley 1
Four Edges
Spool Valve
Line Pressure
Valve
Pulley 2
Actuator
Speed Ratio Control
Main Disadvantage
Constant Flow
Oil supply

• Permanent, constant oil flow required

HydraulicControl Unit
Pressure Differential
Valve
Constant Oil Flow System (PIV)
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Movable sensor plate
sF (axial movement of sensorplate)
Characteristics

• Torque sensor pressure proportional to torque
  at the shaft

• Additional pump function at high torque
  gradients

Conventional Torque Sensor(System PIV)
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Characteristic Curve of Actuator in Conventional
PIV Clamping Systems
400
40
p
p
Pcyl1
Pcyl2
CYL1
CYL2
p
p
pTorque
Pump
TORQUE
PUMP
bar
Nm
e
r
u
s
s
200
20
Torque
shift speed ds/dt
e
r
P
100
10
0
0
-1,5
-1
-0,5
0
0,5
1,5
mm
Slide valve travel
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• Introduction Chain-CVT

• Clamping Systems

• Control Design for Range Shifts in Autarkic
  Hybrid

• Expanded Control Layout for Universal Use in
  Chain Variator Applications

• Summary

Presentation Outline
13
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 lt0,002 required
Driveline of the Autarkic Hybrid
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Selection of control parameters
Absolute value of deviation
u
0
Algebraic sign of deviation
u
Variation of param. (gain scheduling)
Value of control variable
u
CVT Controller, Variable in Structure
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pAb
FAbpAb.Az
Az
FAnpAn.Az
Az
pAn
Influence of Disturbance Variables
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Problem Improved control system is needed for
speed ratio control at SYN (i0,458) during range
shift.
Solution Disturbance feedforward (torque)
Extension of the Speed Ratio Controller
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Extension of the Speed Ratio Controller
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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)

Results and further Aims
19

• Introduction Chain-CVT

• Clamping Systems

• Control Design for Range Shifts in Autarkic
  Hybrid

• Expanded Control Layout for Universal Use in
  Chain Variator Applications

• Summary

Presentation Outline
20

• Main disturbance variables torque and speed ratio
  lead to
• Pulley Misalignment, shaft deflection, pulley
  distortion,
• change in clamping force ratio

Disturbance Variables
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setpoint
CVT
actualvalue
LinearController
Extension of the Control Structure
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Question Where to get the z-map from ?
Output of Linear Controller supposed to be Zero
in steady state!
setpoint
CVT
actualvalue
LinearController
Adaptation of z-map
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Adaptation of the sampling points Value of the
manipulated variable from linear controllerx
weighting factor.

• Weighting functions
• Gauss
• Cone
• ...

Adaptation Law
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START
Visualization and Discussion of the Adaptation
Process
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CVT in Drive Train Configuration

• Power demand leads to desired engine speed.
• New engine speed is achieved by changing the
  CVTs 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

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Control of the Rate ofSpeed Ratio Change di/dt
Modification of the control structure

• Delete Feedback Loop

• Stop Adaptation Process

• Replace Controller

setpoint speed ratio
speed ratio
di/dt
CVT
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Control of the Rate ofSpeed Ratio Change di/dt
pdyn ds/dt / ( ACYLD )

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

• Damping coefficientD f ( speed )

ü 1/i
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Measured Results of the Control ofSpeed Ratio
Change ds/dt
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• Introduction Chain-CVT

• Clamping Systems

• Control Design for Range Shifts in Autarkic
  Hybrid

• Expanded Control Layout for Universal Use in
  Chain Variator Applications

• Summary

Presentation Outline
30

• 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 z-maps can be used for different
  purposes (scientific work, onboard diagnostic
  purposes etc.)
• Further optimization possible (improved di/dt,
  z-max)

Summary
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2004 International Continuously Variable and
Hybrid Transmission Congress September 23-25, 2004
Control and Operating Behavior ofContinuously
Variable Chain Transmissions
Roland Mölle
32
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