Particle Number Emissions of Direct Injected Gasoline Engines

Dr.-Ing. Michael Winkler

Hyundai Motor Europe Technical Center

Particle Number Emissions of

Direct Injected Gasoline Engines

Advanced Emission Control Concepts for Gasoline Engines 2012

May, 21st – 23rd 2012

Hotel Mariott, Sindelfingen, Stuttgart, Germany

ContentContent

� Introduction / HMG engine line-up for Europe

� PN emission benchmark

- PN / PM emissions of Euro 5 gasoline vehicles

- Analysis of sources for PN emission

� PN Reduction

- Calibration measures for PN reduction

- Impact of PN optimized calibration on BSFC

� Summary / Conclusion

PN emissions of GDI EnginesAdvanced Emission Control Concepts

for Gasoline Engines 2012

U-engine

I3: 1.1 75PS

I4: 1.4 – 1.7 136PS

Theta II

I4: 2.0 177PS

I4: 2.0 TCI 275PS

Gamma

I4: 1.4 – 1.6 140PS

I4: 1.6 T-GDI 186PS

Kappa

I3: 1.0 69PS

I4: 1.2 T-GDI >125PS

Diesel

Gasolin

e

R-engine

I4: 2.0 – 2.2 200PS



▣▣▣▣ Powertrain Evolution

S-engine

V6: 3.0 250PS

1.0 1.1 1.2 1.3 1.4

80

60

100

120

140

Displacement [ l ]

Engine Power [ PS ]

I4

I4

I3

κκκκ

2008: κκκκ 1.2l

2011: κκκκ 1.0l

2012: κ 1.4l

2012: κ 1.0l TCI

2013: κ 1.2l T-GDI

κκκκ engine family



▣▣▣▣ Powertrain Evolution



▣▣▣▣ Emission Legislation

NEDC Test Cycle

6*1011#/km ***--PN

4.5**5*PM

<-100HC

<-60NOx

<-1.000CO

by 1. Jan. 2015by 1. Jan. 2011Registration

by 1. Sep. 2014by 1. Sep. 2009Type Approval

Euro 6Euro 5

Emissions in mg/km (Gasoline)

* GDI only

** GDI only and new test method

***GDI only, 3 years 6*1012 #/km upon choice of manufacturer

Hyundai



▣▣▣▣ Emission Legislation

NEDC Test CycleEU15 EU25 EU27

100

120

140

160

180

200

1995 2000 2005 2010 2015 2020

CO2emission (fleet) [ g/km ]

Year [ - ]

all car makers our target 2012:130 g/km

our target 2020:

95g/km

� Short term: PN major driver for gasoline engine development

� Long term: Balance of PN and CO2



▣▣▣▣ PN Benchmark EU 5 Vehicles

NEDCNEDCNEDCNEDCwarmwarmwarmwarm----upupupup

Optimization of Kappa 1.2 T-GDI

NEDC warmNEDC warmNEDC warmNEDC warm

NEDCNEDCNEDCNEDCcoldcoldcoldcold idleidleidleidle

0.E+00

2.E+11

4.E+11

6.E+11

0 200 400 600 800 1000 1200

Time [ s ]

Particle Number [ #/s ]

0

40

80

120

Vehicle Speed [ km/h ]

Analyze

Cold City Mode EUDC mode

▣▣▣▣ PN ReductionParticle Number [N/km]

1010

1011

1012

1013

1014

Particle Mass [mg/km]0.1 1 10 100

EU6 limit GDI Turbo GDI NA PFI Turbo PFI NA GDI strat. NA

Cold Start

0.0E+00

1.0E+11

2.0E+11

3.0E+11

4.0E+11

0 25 50 75 100 125

Time / [s]

Particle Number / [#/s]

0

20

40

60

80

100

120

Vehicle Speed / [km/h]

FS 1.6 GDI (NA)

VW 1.4 T-GDI

1.6 GDI (NA)

Competitor

0.E+00

1.E+11

2.E+11

3.E+11

4.E+11

800 850 900 950 1000 1050 1100 1150 1200Time / [s]

Particle Number / [ #/s ]

FS 1.6 GDI (NA)

VW 1.4 T-GDI

EUDC Mode

1.6 GDI (NA)

Competitor

0.0E+00

1.0E+11

2.0E+11

3.0E+11

4.0E+11

0 200 400 600 800 1000 1200Time / [s]


0

20

40

60

80

100

120


Particulate Number (PN) in #/s

Accumulated PN in (#/km)/10

EU6 PN limit 6*10 1̂1 (#/km)/10

Vehicle Speed in km/h

GDI Turbo

0.0E+00

1.0E+11

2.0E+11

3.0E+11

4.0E+11

0 200 400 600 800 1000 1200Time / [s]


0

20

40

60

80

100

120


PFI Turbo



▣▣▣▣ PN Benchmark EU 5 Vehicles

Particle Number [N/km]

1010

1011

1012

1013

1014

Particle Mass [mg/km]0.1 1 10 100

EU 6 limitGDI TurboGDI NAGDI stratified NAPFI TurboPFI NA

��

��

��

��

��

��

Cold EUDC modeCity Mode

�� warm-up period:

→ PFI engine has lower PN

→ GDI fails during cold start

�� vehicle acceleration→ PFI engine has lower PN

�� high vehicle speed (EUDC) → PFI higher PN during high

speed/load area

BDC210240270300330TDC

4

8

12

16

20

68

72

76

280

277

273

269

265

Fuel Consumption [g/kWh]

2

2

2

BDC210240270300330TDC

4

8

12

16

20

Fuel Pressure [bar]

PN [#/ms]

4*106



PN Reduction by Calibration Measures

BSFC BSFC BSFC BSFC minminminmin

PN PN PN PN minminminmin

∆∆∆∆ BSFC:

+3%

NEDC warmNEDC warmNEDC warmNEDC warm

Particle Number [#/ms]

Fuel

pressure

increase

Too earlyToo earlyToo earlyToo early

Too lateToo lateToo lateToo lateOptimalOptimalOptimalOptimal

� Fuel pressure 150..200 bar for best PN

� Injection timing compromise between piston wetting and mixture preparation

� BSFC increase for PN optimized calibration

Start of Injection [°CA bTDC]Start of Injection [°CA bTDC]

Fuel Pressure [bar]

BSFC [g/kWh]



PN Reduction by Calibration & HardwareNEDC warmNEDC warmNEDC warmNEDC warm

Euro 5 Euro 6

Fuel pressure 50..70bar 150 ..200bar

Injector Layout:

Flow Rate - 20 %

Increase fuel pressure

Targeting

Oil Dilution

…

� PN-emission - 15 %

� Fuel Consumption - 0.8%

BDC210240270300330TDC

4

8

12

16

20

Fuel Pressure [bar]

PN [#/ms]

4*106

Start of Injection [°CA bTDC]

ExhaustTiming [°°°°CA]

Intake Timing [°°°°CA] -30-20-100102030

-10

0

10

20

30

268

272

276

280

277

273

269

265

Fuel Consumption [g/kWh]

BSFC [g/kWh]



PN Reduction by Calibration Measures NEDC warmNEDC warmNEDC warmNEDC warm

EGR

increase

Max. valve

overlap

� Maximum valve overlap for low PN and low BSFC

� Overlap limited by combustion stability (low loads) and knocking (high loads)

Intake Timing [°°°°CA]

EGR

increase

Max valve

overlap

EGR

increase

-30-20-100102030

-10

0

10

20

30

ExhaustTiming [°°°°CA]

EGR

increase

Max valve

overlap

Particle Number [#/ms]

Intake Timing [°°°°CA]

PN [#/ms]

4*106

� Max. possible valve overlap & 150bar fuel pressure (like hot engine)

� Temperature dependent SOI Calibration

10/13PN emissions of GDI EnginesAdvanced Emission Control Concepts


NEDCNEDCNEDCNEDCwarmwarmwarmwarm----upupupup Warm-Up Period

280290300310320330

Start of Injection [ °CA bTDC ]

90 °C

50 °C

30 °C

+200 %

PN [ #/ms ]

1* 107



Cold Idle NEDCNEDCNEDCNEDC

coldcoldcoldcold idleidleidleidle

Crank Angle [°CA]

-360 -180 TDC 180 360

1st Injection

2nd Injection

Ignition

ExhaustIntake

Homogeneous Split Injection

� HSP with late combustion for fast CAT light-off

� 70 bar fuel pressure and no valve overlap

� High impact of timing of 1st and 2nd injection, split ratio less impact

1400rpm / 1.5bar

p_fuel = 70bar

1.0E+06

1.0E+07

1.0E+08

250260270280290300

Start of Injection 1 / [ °CA bTDC ]

PN / [ #/m

s ]

1st Injection p_Fuel 70bar

PN [ #/ms ]

107

Start of Inj.1 [ °CA b TDC ]

300 290 280 270 260 250

1400rpm / 1.5bar

p_fuel = 70bar

1.0E+06

1.0E+07

1.0E+08

40 60 80 100 120 140 160 180

End of Injection 2 [ °CA bTDC ]

PN [ #/ms ]

p_Fuel 70bar

COV <13

2nd Injection

PN [ #/ms ]

107

End of Inj.2 [ °CA b TDC ]

40 80 120 160



Cold Idle / Heat-Up Strategy NEDCNEDCNEDCNEDC

coldcoldcoldcold idleidleidleidle

� Heat-Up strategy compromise between low PN and low HC / CO / NOx

� Strategy to be validated in vehicle calibration

0,0E+00

4,0E+06

8,0E+06

1,2E+07

1,6E+07

2,0E+07

Base Q const Q opt

-9 0 %

-8 0 %

Base Q const Q opt

+ 8

0 %

+ 8

0 %

+ 8

0 %

+ 8

0 %

Particle NumberParticle NumberParticle NumberParticle Number Exhaust Heat FlowExhaust Heat FlowExhaust Heat FlowExhaust Heat Flow

PN [ #/ms ]

4* 106

Q [ kW ]

2

Status PN

PN Reduction

Hardware

Modification



▣▣▣▣ Summary

PN Reduction / %

-- --65 .. 75%

65 .. 75%

65 .. 75%

65 .. 75%

-- --90 %

90 %

90 %

90 %

-- --80 .. 90 %

80 .. 90 %

80 .. 90 %

80 .. 90 %

GDI

PFINEDC warmNEDC warmNEDC warmNEDC warm

Areas for

Optimization

PN- Filter

?200bar Fuel

Pressure

Hot Warm-

up

Cold

idle

BSFC

+0 ..5 %

Hyundai Motor Europe

Technical Center

Documents

Particle Number Emissions of Direct Injected Gasoline Engines