Two-Stage Variable Compression Ratio (VCR) System to Increase ...

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Dearborn, October 16 th , 2012 Two-Stage Variable Compression Ratio (VCR) System to Increase Efficiency in Gasoline Powertrains DEER Conference 2012 D. Tomazic, H. Kleeberg, S. Bowyer, FEV Inc. J. Dohmen, K. Wittek, B. Haake, FEV GmbH

Transcript of Two-Stage Variable Compression Ratio (VCR) System to Increase ...

Page 1: Two-Stage Variable Compression Ratio (VCR) System to Increase ...

Dearborn, October 16th, 2012

Two-Stage Variable Compression Ratio (VCR) System to Increase Efficiency in Gasoline Powertrains

DEER Conference 2012

D. Tomazic, H. Kleeberg, S. Bowyer, FEV Inc.

J. Dohmen, K. Wittek, B. Haake, FEV GmbH

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Content

Introduction and motivation

Layout of FEV’s two-stage VCR system

CO2 reduction potential

Combination with future technologies

Summary and conclusion

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Introduction and Motivation Principle Influence of Compression Ratio on Fuel Consumption

3

Compression ratio (CR) [-]

BSF

C [%

]

high

100

low

CRbase

2000 rpm / WOT 2000 rpm / BMEP = 2 bar

14 8

VCR

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Introduction and Motivation Classification of VCR Systems

Variable piston TDC position

εmin

εmax

Unconventional cranktrains

Variable distance head - crankshaft

Variable kinematic lengths

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Content

Introduction and motivation

Layout of FEV’s two-stage VCR system

CO2 reduction potential

Combination with future technologies

Summary and conclusion

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Layout of FEV’s Two-stage VCR System Working Principle: Conrod

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Layout of FEV’s Two-stage VCR System Working Principle: Mechanical Actuation

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Cam disc carrier

View from top

horizontal movement

valve body

functional surface

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Layout of FEV’s Two-stage VCR System Transition Time During Load Step

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actual CR ideal CR

high

low -0.2 0.0 0.2 0.4 0.6 0.8 1.0

2500

2000

1500

1000

500

0

CR

[-]

Acce

lera

tor

Peda

l [-]

Manifold pressure [m

bar]

Time [s]

Full Load

Part Load

n = 2000 rpm Oil temp. = 90°C

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Layout of FEV’s Two-stage VCR System Influence of Oil Temperature

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0 . 0 0 . 2 0 . 4 0 . 6 0 . 8 1 . 0

high

low

CR

[-]

Time [s]

n = 2000 rpm BMEP = 8 bar Oil temp.:

0°C 90°C

CR ‘low high‘ CR ‘high low‘ �̇� = 𝛼𝐷 ⋅ 𝐴 ⋅

2Δ𝑝𝜌

12-04-27_WMS_2012_VCR.pptx K. Wittek

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© by FEV – all rights reserved. Confidential – no passing on to third parties

Content

Introduction and motivation

Layout of FEV’s two-stage VCR system

CO2 reduction potential

Combination with future technologies

Summary and conclusion

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50 kph, 3rd gear

70 kph,5th gear

120 kph, 6th gear

50 kph, 3rd gear

70 kph,5th gear

120 kph, 6th gear

BM

EP [b

ar]

0

5

10

15

20

25

Engine Speed [rpm]1000 2000 3000 4000 5000

1312

1110

9

8

14

ε =

Continuous VCR

CO2 Reduction Potential Compression Ratio Maps Continuous VCR vs. Two-stage VCR

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Engine Speed [rpm]1000 2000 3000 4000 5000

131211109876543210

Fuel Sharein NEDC [%]

VCR shift line

ε = 12

ε = 8

Two-stage VCR CR 8/12

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CO2 Reduction Potential Influence of CR-stages on the VCR Shift Line and BMEP at WOT

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50 kph, 3rd gear70 kph, 5th gear

BM

EP [b

ar]

0

5

10

15

20

25

Engine Speed [rpm]1000 2000 3000 4000 5000

CR 9/14 CR 8/12

120 kph, 6th gear

VCR shift lines 8 ↔ 12

9 ↔ 14

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Layouts of CR stages

8/12 8/13 8/14 9/14 10/14

CO2 Reduction Potential Simulation Boundaries - Europe

Vehicle IWC 1372 kg

6-speed MT

2.0 L TC GDI, RON 95

Pmax = 180 kW (const.)

Base CR 9,6 (BMEPmax = 22 bar)

BMEPmax (function of CRlow)

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CO2 Reduction Potential Simulation Results - Europe

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1 0 0

1 1 0

1 2 0

1 3 0

1 4 0

1 5 0

1 6 0

CO

2 Em

issi

on [g

/km

]

Base fixed CR

NEDC

-5.6% -5.9% -5.7% -5.8% -5.5%

WLTP

-5.1% -5.2% -4.5% -5.0% -4.3%

CR = 9.6 CR = 8/12 CR = 8/13 CR = 8/14 CR = 9/14 CR = 10/14

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CO2 Reduction Potential Simulation Results - USA

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FTP 75Full size sedan

Baseline CR = 9/12 CR = 9/13 CR = 9/14 CR = 10/12 CR = 10/13 CR = 10/14

CO

2 E

mis

sion

s [g

/km

]

170

175

180

185

190

195

200 Premium Fuel Regular Fuel

-4.8%-3.9%-2.8%

-4.5% -5.3% -6.0% -4.8% -6.5%-5.6%

-2.8% -4.0% -4.8%

CR

= 1

0.5

CR

= 1

0

Vehicle: 1670 kg (3682 lbs) Engine: 2.0L GTDI w/ P = 180 kW; RON 95 Transmission: 7 Speed wet DCT

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CO2 Reduction Potential Simulation Results - USA

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Fuel share in FTP75 [%]

BM

EP [b

ar]

0

2

4

6

8

10

12

14

16

18

20

22

24

Engine Speed [rpm]1000 2000 3000 4000 5000 6000

Turbocharged DI 2.0L CR=10/14

CR = 14

CR = 10

FTP75 - Full Size Sedan w/ Premium Fuel

6

5

4

3

2

1

0

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CO2 Reduction Potential Simulation Results - USA

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BM

EP [b

ar]

0

2

4

6

8

10

12

14

16

18

20

22

24

Engine Speed [rpm]1000 2000 3000 4000 5000 6000

Turbocharged DI 2.0L CR=10/14

CR = 14

CR = 10

US06 - Full Size Sedan w/ Premium Fuel

8

7

6

5

4

3

2

1

0.8

0.5

0.3

0

Fuel share in US06 [%]

Page 18: Two-Stage Variable Compression Ratio (VCR) System to Increase ...

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Content

Introduction and motivation

Layout of FEV’s two-stage VCR system

CO2 reduction potential

Combination with future technologies

Summary and conclusion

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Combination with Future Technologies

Alternative fuels

Gasoline controlled auto ignition (GCAI)

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‘Extreme downsizing’

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1 0 0

1 1 0

1 2 0

1 3 0

1 4 0

1 5 0

1 6 0

CO

2 Em

issi

on [g

/km

] Combination with Future Technologies Two-stage VCR Combined with ‘Extreme’ Downsizing

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Inertia weight class: 1372 kg 6-speed MT, gear ratios adapted Pmax = 180 kW (const.)

Base fixed CR

NEDC WLTP

-5.9%

-5.2%

2.0l, CR = 9.6 2.0l, CR = 8/13

‘Extreme Downsizing‘ Fixed CR

1.5l, CR = 8.2

-7.1%

-6.5%

1.5l, CR = 8/12

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Combination with Future Technologies Two-stage VCR Combined with GCAI - Gasoline Controlled Auto Ignition

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Base vehicle: 1372 kg, 1.8L -4% CO2 in NEDC

Fixed CR = 9.8

GCAI operation area

Load too low for GCAI

Two-stage VCR CR = 9.8/13 -12% CO2 in NEDC

Load too high for GCAI

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Combination with Future Technologies Two-stage VCR Combined with Alternative Fuels

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BM

EP [b

ar]

0

5

10

15

20

25

Engine Speed [rpm]1000 2000 3000 4000 5000

2.0l, TC, Two-Stage VCR 8/12 (optimized for RON 95)

RON 95

RON 98

RON 91

Exx

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Page 23: Two-Stage Variable Compression Ratio (VCR) System to Increase ...

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Two-stage VCR System Summary and Conclusions

VCR can help to resolve the conflict between part load and full load CR layout especially for boosted downsized gasoline engines

The presented two-stage VCR system is based on a variable length conrod with eccentric piston pin suspension and can be adapted to existing engines with moderate effort

The transition time can be adjusted according to the thermodynamic requirements

CO2 reduction potential for moderate downsized GDI engines 5 – 6% Increased benefit for extreme downsized GDI engines of up to 7% in NEDC Operating area of GCAI technology can be significantly enlarged resulting in

up to 12% CO2 reduction in combination with two-stage VCR in NEDC The higher knock resistance of alternative (flex) fuels can be used via

adaptation of the VCR shift line in the map

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Page 24: Two-Stage Variable Compression Ratio (VCR) System to Increase ...

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DEER Conference 2012 Two-stage VCR system

Thank you for your kind attention!

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