VT2+: Further improving the fuel

economy of the VT2 transmission

Gert-Jan Vogelaar

Punch Powertrain

21/03/2011 CVT2010 2

Introduction

• VT2 in the market

• Project approach

• Transmission losses

• Flexibility and range

• Idle stop and idle speed

• Summary of improvements

• Conclusions

21/03/2011 CVT2010 3

Current VT2 Applications

21/03/2011 CVT2010 4

Fuel consumption comparison

-6,0%

-4,0%

-2,0%

0,0%

2,0%

4,0%

6,0%

8,0%

2008 2009 2010 2011 2012 2013

DCT

AMT

VT2 Applications

Trend VT2

• VT2 applications keep on achieving better fuel economy

• From 2011, as good as Manual Transmission

• VT2 gets within range of DCTs and AMTs

21/03/2011 CVT2010 5

Project approach

• Identify relevant working areas

• Identify contribution of different losses

• Attack the most contributing losses

• Identify limiting factors on flexibility and range

• Select and improve critical components

21/03/2011 CVT2010 6

Transmission losses

• Relevant areas:

– Driving in Overdrive

– Losses at standstill

• Only these areas are investigated

21/03/2011 CVT2010 7

Losses in OD

Losses in Overdrive

variator

48%

pump

17%

drag R clutch

2%

drag D clutch

0%

pre-tension

bearings

4%

bearings/gears

1%

other

28%

Losses in OD reduced by 19%

variator

34%

Improvement

due to

improved

clamping

control

19%

drag D clutch

0%

drag R clutch

2%

pump

12%

pretention

bearings

4%

bearings/gears

1%

other

28%

• Main losses in Overdrive caused by pump and variator

• 19% reduction via improved clamping control

• Corresponds to approximately 1.5% on NEDC cycle

21/03/2011 CVT2010 8

Losses at standstillLosses at standstill in D

drag R clutch

2%

other

16%

variator

0%

drag D clutch

69%

pump

13%

pretention

bearings

0%

bearings/

gears

0%

Losses at standstill

reduced by 67%

pretention

bearings

0%

bearings/gears

0%

pump

13%

drag D clutch

2%

variator

0% drag R clutch

2%

other

16%

Improvement

due to improved

clutch control

67%

• Drag in D clutch by far the biggest cause of losses

• Reduction of 67% realised via improved clutch control

• Corresponds to 1-1.5% on NEDC cycle

21/03/2011 CVT2010 9

Flexibility and range

• Approach: Try to lower engine speed whenever possible

• Via optimising variogram in software

• Via improving oil balance

-6,0%

-4,0%

-2,0%

0,0%

2,0%

4,0%

6,0%

8,0%

2008 2009 2010 2011 2012 2013

Improvement via:

Improved clutch controlImproved variogram

Improved warm up cycle

21/03/2011 CVT2010 10

Improving oil balance

Engine speed

Oil

flo

ws

Oil supply

Available for shifting

Consumers

Required for shifting

Minimum engine

speed out of

Low ratio

Engine speed

Oil f

low

s

Oil supply

Available for shifting

Old available flow for shifting

Required for shifting

Improvement in

minimum engine

speed out of Low

• Bigger oil pump improves supply, but increases transmission losses

• Improved pressure regulators reduce the oil consumption

• Via both measures animprovement of 1.9% can be

realised (measured)

Engine speed

Oil f

low

s

Oil supply old

Available for shifting

Old available flow for shifting

Required for shifting

Improved oil supply

Improvement in

minimum engine

speed out of Low

21/03/2011 CVT2010 11

Idle stop and idle speed

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Total driving Overall total Total stand still

1st cycle

2nd cycle

3rd cycle

4th cycle

• VT2 includes idle stop capability, without mechanicaladaptation

• Contribution of fuel consumption during idle measuredbetween 8-14%, but what part can effectively be reduced?

• In case during first two ECE cycles, idle stop is not yetapplied, approximately 6% improvement can be realised

21/03/2011 CVT2010 12

Summary of improvements

Option availableNow-9.9%-6.0%*Idle stop

Improvement estimated,

hardware testing started.

2012-5.3%-1.2%Idle speed

Improvement measured.

Hardware testing started.

2012-4.1%-1.9%Oil consumption

Test result. Validation on-going2011-2.3%-1.2%New oil

Simulation result,

SW under development

2011-1.1%-1.5%Clamping control

Improvement measured,

SW validated

2011+0.4%-4.1%Clutch control, variogram,

warm up cycle

Production2010+4.7%-Baseline

StatusByFE vs. MT

(cumm)

FE vs.

VT2

Improvement

* Maximum value. Value will reduce if idle speed is reduced, but the sum of idle stop and idle speed

improvements will not be lower than 6%.

21/03/2011 CVT2010 13

Future improvements on VT2

-10,0%

-8,0%

-6,0%

-4,0%

-2,0%

0,0%

2,0%

4,0%

6,0%

8,0%

2008 2009 2010 2011 2012 2013

Without idle stop

Including idle stop

Historical trend

DCT

AMT

21/03/2011 CVT2010 14

Conclusions

• Via a simple and straightforward approach, the weakareas in the VT2 could be determined and improved

• From 2011, VT2 can deliver similar fuel economy as the MT of the same vehicle

• Additional planned SW and HW improvements will givethe VT2 a benefit over MT of 4.4% in the NEDC by 2012

• From 2011, VT2 can be 5% better than an MT in the NEDC if the idle stop option will be used

• From 2012 VT2 can be 9% better than an MT in the NEDC if the idle stop option will be used

• With these improvements, VT2 can match or do betterthan the best AMTs and DCTs

Thank you for your attention

21/03/2011 CVT2010 16

Further outlook

-8.5%-2.0%Hydraulics, controls

-6.7%-1.5%Curved pulleys / chain

-13.0%-6.0%*Idle stop

-5.3%-1.2%Idle speed

-4.1%-1.9%Oil consumption

-2.3%-1.2%New oil

-1.1%-1.5%Clamping control

+0.4%-4.1%Clutch control, variogram, warm up cycle

+4.7%-Baseline

FE vs. MT (cumm)FE vs. VT2Improvement

• Hybridisation: See presentation by P. Debal

* Maximum value. Value will reduce if idle speed is reduced, but the sum of idle stop and idle speed

improvements will not be lower than 6%.