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Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018 Stani Bohac [email protected] 1
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Page 1: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Benchmarking and Characterization of a

Full Continuous Cylinder Deactivation System

SAE World Congress

April 10-12, 2018

Stani Bohac

[email protected]

1

Page 2: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Benefits and Challenges of Cylinder Deactivation

CDA has the potential to improve engine efficiency at relatively low cost.

• Reduced pumping

• Reduced cylinder heat transfer

• Improved throttle response

Challenges:

• Transitions

• NVH

• Durable deactivation system

• Benefit limited to low engine load

2

Page 3: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Types of Cylinder Deactivation

EPA considering two types of CDA:

deacPD = partial discrete (e.g., 8 or 4 cylinders)

deacFC = full continuous (e.g., continuous between 0-8 cylinders)

3

Page 4: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Why is EPA Interested?

EPA continuously evaluates advanced technologies to support the setting of appropriate GHG standards.

➢ Light-duty GHG standards through 2025 are being reconsidered and revised.

EPA’s prior analysis1 considered deacPD but not deacFC.

DeacFC is a potential enabler for meeting GHG standards2.

This investigation was conducted to benchmark and characterize deacFC and evaluate its potential as an

advanced, production-ready technology for reducing GHG emissions.

1) EPA, 2017, EPA-420-R-17-001

2) Younkins et al., 2017, 38th International Vienna Motor Symposium

4

Page 5: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

.._____~/ [ _________ ]

.._____~/ [ l

------,/ [ ] ~~

[ l

Objectives

Characterize effectiveness and fly zone of deacFC

• Steady-state tests

✓ EPA chassis benchmarking – V8

✓ Tula engine publications – V8, I4

• Drive cycle tests

✓ EPA benchmarking – V8

✓ Tula publications – V8

Initial full vehicle modeling using ALPHA

effectiveness curves

for I3, I4, V6, V8

deacFC fly zone

Compare drive cycle

efficiencies from

simulation and lab

Compare deacFC benefit

on two vehicle types

5

Page 6: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

deacFC Vehicles

Tula Technology Dynamic Skip Fire (DSF) applied to

2011 GMC Yukon Denali 6.2L L94

• fires 0-8 cylinders

• EPA and Tula

Photo by Tula

Photo by Tula

Tula Technology DSF applied to

2015 VW Jetta 1.8L EA888

• fires 0-4 cylinders

• Tula

6

Page 7: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Steady-State Operation

7

Page 8: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

deacFC benefit on V8 (EPA benchmarking)

Test vehicle provided by Tula Technology

MY2011 GMC Yukon Denali 2WD

6.2L L94 V8 PFI gasoline engine

6L80 6-speed automatic transmission

Tier 2, 93 AKI test fuel

“V8 mode” “deacFC mode” • GM ECU, disabled AFM • Tula ECU, deacFC

• Torque converter slip: 17-39 rpm • Torque converter slip: 28-85 rpm

8

Page 9: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Steady-State Chassis Tests (EPA benchmarking)

Vehicle

• 49 and 81 mph

Engine

• deacFC and V8 mode

• 1200 – 2600 rpm

• 0.3 – 5.8 bar BMEP (add variable gradient load to SET road load)

Torque Converter

• 17 – 85 rpm slip

Transmission

• 5th and 6th gear

Component Loss Source

Electrical load 0.42 kW benchmarking

Torque converter 0.03 – 2.17 kW engine speed and torque, chassis roll speed

Transmission 1.31 – 3.82 kW 2014 GM 6L80 benchmarking3

Differential 0.38 – 2.65 kW 1999 Ford 3.55 differential/axle benchmarking4

Drive tires 2.35 – 3.90 kW Crr=0.0095, test weight=6000 lbs, wt dist.=55/45 3) Stuhldreher et al., SAE 2017-01-5020

4) EPA and SwRI, 1999, Contract No. 68-C7-0012

5) NAS, 2006, Tires and Passenger Vehicle Fuel Economy

9

Page 10: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

...

deacFC benefit on V8 (EPA benchmarking)

chassis dynamometer testing

MY2011 Yukon Denali

GM 6.2L L94 V8 PFI engine

Tier 2, 93 AKI test fuel

0

5

10

15

20

25

30

35

40

45

50

55

60

-1 0 1 2 3 4 5 6 7 8 9 10

Re

du

ctio

n in

BSF

C (%

)

BMEP (bar)

chassis dyno, ~2000 rpm

curve fit from 0-6 bar

y = 0.03687x4 - 0.8740x3 + 7.613x2 - 30.03x + 49.02

chassis dyno, ~1200 rpm

chassis dyno, ~2300 rpm

0

5

10

15

20

25

30

35

40

45

50

55

60

-1 0 1 2 3 4 5 6 7 8 9 10

Re

du

ctio

n in

BSF

C (%

)

BMEP (bar)

V8

I3I4

V6

ALPHA full vehicle model

(EPA effectiveness)

10

Page 11: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

~ ... ..c:

500

450

~ 400 ~ ~ (.) ~ 350 co

300

~ ~

250 ..._ ___ ._ __ ___.._ __ ___..__ __ ___..__ __ ___. ___ __. ___ __. ___ __. ___ __,

0 2 3 4 5 BMEP (bar)

6

Figure 7: Fuel Consumption for DSF and VB operation, 1600 RPM

7 8 9

deacFC benefit on V8 (Tula publication)

engine dynamometer testing2

GM 6.2L L94 V8 PFI engine V8 = no cylinder deactivation 1600 rpm

93 AKI fuel DSF = Dynamic Skip Fire * GHG standards call for Tier 2 test fuel

(Tula deacFC) * deacFC benefit would be lower with lower AKI

0

5

10

15

20

25

30

35

40

45

50

55

60

-1 0 1 2 3 4 5 6 7 8 9 10

Re

du

ctio

n in

BSF

C (%

)

BMEP (bar)

curve fit to 0 bar

y = 0.007750x4 - 0.3082x3 + 4.400x2 - 26.73x + 58.22

V8 engine dyno data

11

• Extrapolating benefit to -2 bar adds less than

0.1% benefit in FTP-75 (simulation result)

because engine doesn’t spend time here.

2) Younkins et al., 2017, 38th International Vienna Motor Symposium

Page 12: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

/

6 BMEP [bar]

8

.---_l______l

10 12

deacFC benefit on I4 turbo (Tula publication)

engine dynamometer testing6

VW 1.8L EA888 I4 turbo engine

1600 rpm

87 AKI CARB fuel • GHG standards call for Tier 2 test fuel

• Use of 87 AKI gives a lower (conservative) deacFC benefit

0

5

10

15

20

25

30

35

40

45

50

55

60

-1 0 1 2 3 4 5 6 7 8 9 10

Re

du

ctio

n in

BSF

C (%

)

BMEP (bar)

I4 turbo engine dyno data

curve vit to 0 bar

y = 0.004788x4 - 0.07890x3 + 1.280x2 - 12.22x + 38.15

6) Fuschetto et al., 2017, Oral-Only Presentation, SAE World Congress

12

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J

deacFC benefit scaled to V8, V6, I4, I3 (Tula publication)

Assume benefit at 0 bar scales with cylinder number (NVH)

I3, I4, V6 curves for 87 AKI tests (conservative) since GHG

standards specify 93 AKI

ALPHA full vehicle model

(Tula effectiveness)

0

5

10

15

20

25

30

35

40

45

50

55

60

-1 0 1 2 3 4 5 6 7 8 9 10

Re

du

ctio

n in

BSF

C (%

)

BMEP (bar)

V8

I3I4

V6

0

5

10

15

20

25

30

35

40

45

50

55

60

-1 0 1 2 3 4 5 6 7 8 9 10

Re

du

ctio

n in

BSF

C (%

)

BMEP (bar)

potentially due to cylinder count

I4

V8

87 AKI93 AKI

13

Page 14: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Comparing EPA Chassis and Tula Engine deacFC Effectiveness

0

5

10

15

20

25

30

35

40

45

50

55

60

-1 0 1 2 3 4 5 6 7 8 9 10

Re

du

ctio

n in

BSF

C (%

)

BMEP (bar)

V8

I3I4

V6

0

5

10

15

20

25

30

35

40

45

50

55

60

-1 0 1 2 3 4 5 6 7 8 9 10

Re

du

ctio

n in

BSF

C (%

)

BMEP (bar)

V8

I3I4

V6 Tula Engine Tests

EPA Chassis Tests

0

5

10

15

20

25

30

35

40

45

50

55

60

-1 0 1 2 3 4 5 6 7 8 9 10

Re

du

ctio

n in

BSF

C (%

)

BMEP (bar)

deacFC benefit on V8 from

EPA chassis measurements

deacFC benefit on V8 from

Tula engine measurements

❖ EPA and Tula effectiveness curves are

very similar.

14

Page 15: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Drive Cycle Operation

15

Page 16: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

deacFC benefit on V8 (Tula publication2)

Chassis dynamometer testing

MY2011 GMC Yukon Denali 2WD

6.2L L94 V8 PFI gasoline engine

6L80 6-speed automatic transmission

Tier 2, 93 AKI test fuel

“V8 mode” “deacFC mode” • GM ECU, disabled AFM and DFSO • Tula ECU, deacFC and DFSO

• GM transmission shift strategy • Slightly higher torque converter slip

Photo by Tula

2) Younkins et al., 2017, 38th International Vienna Motor Symposium

16

Page 17: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

17% FE Improvement

US City

' ' . ' ' . . . . '

j 100 ··········r··········~··········j-··········r··········1···········1···········

(/) (/)

>

200 400 600 800 1000 1200 1400 Time (s)

i ,: ir II~ \l~I . . ' ' . . . . ' ' . .

o ~~-~-~-~-~-~~

200 400 600 800 1000 1200 1400 Time (s)

50 ,.........----------------,

c 40 ··• ············<·············••i••······ ····'······· ···· <············••i••

i 30 ) ........... · j · ....... ····; ···· .. ····,··············~··

~ ; : : O 20 -+······· +· ' -;,4;!. 10 .. .:. ....... .

0 0 20 40 60 80 100

9.0% FE Improvement

US Highway

0 ~--~--~---~-~ 200

50

200

400 Time (s)

400 Time (s)

600

600

50,-.----------~----, i

40 ... i ............ '· ........ -r····· .. -r··· ...... i .. 30 ··;·············;·· •·-·····;···········;············ ;············;·· 20 .. ; ......... i ......... ; .......... ; . ;

0 20 40 60 80 100

6.1% FE Improvement

US06

100 ......... . ···· ··-···· ··· ···

I : 50

100 200 300 400 500 600 Time (s)

100

100 200 300 400 500 600 Time (s)

50 ,.........-------------------, 40 .. 1. ......... , ...... ··T··· ····+·· ......... j.

30 ·+······· ·····;········· ;·············;•··•·····

20 ........... : ....... · ..... .L ........ ··· ! ....... · ..... l· .... · .... . 10 i ; :

0 0 20 40 60 80 100

Firing Density(%) Firing Density(%) Firing Density(%)

Figure 12: Results of Fuel Economy Testing with DSF, compared to VB operation

deacFC benefit on V8 (Tula publication2)

FTP-75 HWFET US06

2) Younkins et al., 2017, 38th International Vienna Motor Symposium

17

Page 18: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

deacFC benchmarking at EPA

Drive cycle benchmarking performed to:

1) Compare EPA and Tula results

2) Quantify deacFC ‘fly zone’ needed for

vehicle modeling

Test vehicle:

MY2011 GMC Yukon Denali 2WD

6.2L L94 V8 PFI gasoline engine

6L80 6-speed automatic transmission

Tier 2, 93 AKI test fuel

“V8 mode” “deacFC mode” • GM ECU, disabled AFM and DFSO • Tula ECU, deacFC and DFSO

• GM transmission shift strategy • Slightly higher torque converter slip

• Passed Tier 2 bin 5 NMOG, CO, NOx, PM • Passed Tier 2 bin 5 CO, NOx, PM

18

Page 19: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

deacFC benefit on V8

Tula publication2 EPA benchmarking*

FTP-75 17.0 % 13.4 % (14.6 → 16.5 mpg)

HWFET 9.0 % 9.9 % (25.0 → 27.5 mpg)

US06 6.1 % 9.5 % (14.4 → 15.7 mpg)

EPA benchmarking shows:

• Smaller deacFC benefit in FTP-75, higher deacFC benefit in HWFET and US06

• Average of 3 cycles almost identical (10.9% versus 10.7% improvement)

Why the difference?

• different driver, different lab, different day

• deacFC benefit is the ratio of 2 tests (MPGdeacFC/MPGV8); error stacking

Note

• DFSO is active in deacFC mode but not in V8 mode

• Full vehicle modeling7 shows DSFO provides 2.5% benefit in FTP-75 and 1.2% in

HWFET in V8 mode. 2) Younkins et al., 2017, 38th International Vienna Motor Symposium

7) ALPHA model introduced by Lee et al., SAE 2013-01-0808

* Average of 2 tests in V8 mode / average of 2 tests in V8 mode

19

Page 20: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

deacFC benefit on V8 – FTP-75 by Bag (EPA benchmarking)

deacFC relative to V8

(% improvement in MPG)

Comment

Bag 1 7.1 % deacFC inactive until oil warms

Bag 2 15.8 % Lowest engine loads

Bag 3 14.0 % Higher loads than bag 2

20

Page 21: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

EJ

!

deacFC benefit on V8 – FTP-75 by Mode (EPA Benchmarking)

0

10

20

30

40

50

60

70

80

1 6 11 16 21 26 31

FE (

mp

g)

Mode Number of FTP-75 (Bag 1)

deacFC

110 s

0

10

20

30

40

50

60

70

80

82 87 92 97 102 107 112

FE (

mp

g)

Mode Number of FTP-75 (Bag 3)

deacFC

V8

Bag 1

Bag 3

0

10

20

30

40

50

60

70

80

32 37 42 47 52 57 62 67 72 77

FE (

mp

g)

Mode Number of FTP-75 (Bag 2)

deacFC

V8

Bag 2

• deacFC becomes active after 110 s.

• deacFC advantage only present when

FE is high (low engine load).

21

Page 22: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

deacFC Fly Zone on V8 (EPA benchmarking)

Used FTP-75, HWFET, US06 tests and MAP to quantify V8 deacFC fly zone.

Activate deacFC if all conditions are true:

1) > 47.3°C Tcoolant

2) Engine speed > 940 rpm

3) Gear = 2-6

ALPHA full vehicle model

22

Page 23: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Full Vehicle Modeling

23

Page 24: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

500

400

300

E z

~ e-0 ,_

200

-100 1000 1500

2014 GM EcoTec3 LV3 4.3L Tier2 converted to 6.12L 8 Cylinder Brake Specific Fuel Consumption ( g/kWAhr)

175kW

150kW

125kW

100kW

12.5 kW

-------_-_-_-_-_-_-_-_-_-_-_-_-_-_-_----=-=1•12.5 kW - _ -25 kW

2000 2500 3000 3500 4000 4500 5000 5500 Speed ( RPM )

ALPHA Full Vehicle Model of V8 Yukon

ALPHA full vehicle model7

Vehicle characteristics Test weight=6000 lbs

Road load coefficients: A=32.15 lb, B=1.0382 lb/mph, C=0.02111 lb/mph2

Engine GM 4.3L LV3 engine8 scaled to GM 6.2L L94 considering9:

Heat transfer

Friction

Knock propensity

Engine inertia=0.33 kg/m2 (scaled based on displacement)

deacFC effectiveness curve from

a) EPA chassis tests

b) Tula engine tests

deacFC fly zone from EPA chassis tests

DFSO

allowed in deacFC mode

not allowed in V8 mode

Torque converter Locked

Semi-locked

26 rpm slip in V8 mode

55 rpm slip in deacFC

Unlocked

Transmission 2014 GM 6L80 benchmarking3

Min. downshift speed=540 rpm

Min. upshift speed=1200 rpm

Differential 3.42 ratio

1999 Ford 3.55 differential/axle benchmarking4

Tier 2 Fuel: ρ=0.74277 g/cm3@60F

H/C=1.836 molar ratio

LHV=42.898 MJ/kg

Min BSFC as a function of power

3) Stuhldreher et al., SAE 2017-01-5020

4) EPA and SwRI, 1999, Contract No. 68-C7-0012

7) Lee et al., SAE 2013-01-0808

8) Stuhldreher, SAE 2016-01-0622

9) Dekraker et al., SAE 2017-01-0899

24

Page 25: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Chassis Tests and Full Vehicle Model – V8 Yukon

EPA chassis dyno ALPHA model

EPA chassis dyno effectiveness

FTP-75 14.6 → 16.5 mpg

13%

14.7 → 16.5 mpg 13%

HWFET 25.0 → 27.5 mpg

10 %

24.9 → 27.5 mpg 11 %

• deacFC mode (with DFSO) compared to V8 mode (no DFSO)

• DFSO provides 2.5% benefit in FTP-75 and 1.2% in HWFET in V8 mode

Tula chassis dyno2 ALPHA model

Tula engine dyno effectiveness

FTP-75 17% 18%

HWFET 9% 16%

• deacFC mode (with DFSO) compared to V8 mode (no DFSO)

• DFSO provides 2.5% benefit in FTP-75 and 1.2% in HWFET in V8 mode

2) Younkins et al., 2017, 38th International Vienna Motor Symposium

25

Page 26: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Combined Cycle Simulation Results

2011 Large SUV and 2025 Midsize Car CO2 Reduction (g/mi)

Only Adding deacFC

Vehicle Description Combined Cycle

2011 Large SUV

Photo by Tula

Vehicle: 2011 GM Yukon Denali

Engine:

2014 GM 4.3L LV3 scaled to 6.2L9

DFSO

no stop/start

no AFM

2011 GM Yukon accessories

deacFC effectiveness from EPA chassis tests

Transmission: 6-speed GM 6L80

8.8%

2025 Midsize Car

The Jetsons

Vehicle: typical 2016 midsize car10 with:

7.5% curb weight reduction

10% aerodynamic improvement

10% coefficient of rolling resistance reduction

Engine:

2016 Honda 1.5L L15B7 scaled to 1.42L9,10

DFSO

stop/start

no CDA

high efficiency accessories11

deacFC effectiveness from EPA chassis tests, scaled to I4

Transmission: future 8-speed11

2.6%

9) Dekraker et al., SAE 2017-01-0899

10) Stuhldreher et al., SAE 2018-01-0319

11) EPA, 2016, EPA-420-R-16-021

26

Page 27: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Summary and Conclusions

Characterized deacFC effectiveness and fly zone

• Demonstration vehicle that met NVH and emissions constraints

• Benefit curves for I3, I4, V6, V8

• Fly zone

Conducted preliminary full vehicle modeling

• deacFC-equipped 6.2L Yukon

• Compared drive cycle efficiencies from chassis tests and full vehicle model

• Compared combined cycle CO2 reduction for 2011 large SUV and 2025 midsize car

Based on this investigation, EPA considers deacFC to be a promising production-ready technology

for reducing GHG emissions.

27

Page 28: Benchmarking and Characterization of a Full Continuous ... · Benchmarking and Characterization of a Full Continuous Cylinder Deactivation System SAE World Congress April 10-12, 2018

Acknowledgements

Tula Technology

Matthew Younkins and Sam Hashemi for providing Tula Yukon Denali test vehicle.

EPA NVFEL

Scott Ludlam, Paul Burbage, Michael Matthews, Garrett Brown for chassis testing.

EPA NCAT

Kevin Newman, Paul Dekraker, Dan Barba for ALPHA modeling and guidance.

28


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