Iddo Riemersma, 13th plenary meeting of the Off-Cycle Informal Working Group, 5-7 April 2006

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WNTE

WNTE control area evaluation with respect tothe real-world engine operation envelope

OCE Informal Document No. 42Thirteenth Plenary Meeting of the Working Group On Off-Cycle Emissions

5 & 6 April 2006The Hague, Netherlands

6 April 20062

IntroductionMain question:

Is the proposed WNTE control area sufficiently wide enough?

or

Are there spots in the engine map (outside the proposed control area) that have a significant contribution in real life operation emissions?

and if so,

If/how could these points be added to the proposed control area?

6 April 20063

Presentation overview

I. Review of lower engine speed limit of the NTE zoneII. Methodology for calculating emission contributionsIII. Preliminary results for typical cases of vehicle and applicationIV. Further steps: WNTE evaluation project for DG Enterprise

6 April 20064

0

0 ,2

0 ,4

0 ,6

0 ,8

1

1 ,2

0 0 ,2 0 ,4 0 ,6 0 ,8 1 1 ,2 1 ,4N o rm a l ise d e n g in e sp e e d

Norm

alis

ed e

ngin

e to

rq

m ax . to rqueN TE z one30% pow er70% pow erA , B and C s peed

P M c arve-ou t

WNTE control area (work.doc. version 8) N

orm

alis

eden

gine

torq

ue

Control area for ‘average’ Euro 3 engine

Lower speed limit based on US NTE approach at nlo+0.15(nlo+nhigh)

6 April 20065

0

0,2

0,4

0,6

0,8

1

1,2

0 0,2 0,4 0,6 0,8 1 1,2 1,4No r m alis e d e n g in e s p e e d

Nor

mal

ised

eng

ine

torq

m ax . torqueN TE z one30% pow er70% pow erA , B and C s peed

P M c arve-out

WNTE control area (work.doc. version 9) N

orm

alis

eden

gine

torq

ue

Control area for ‘average’ Euro 3 engine

Lower speed limit is 25th percentile of cum. frequency for WHTC incl. idle

6 April 20066

WHTC cumulative frequency including idle

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.0% 10.0% 20.0% 30.0% 40.0% 50.0% 60.0% 70.0% 80.0% 90.0% 100.0%

nnorm

cum

ulat

ive

frequ

ency

29%

31%

6 April 20067

WHTC cumulative frequency excluding idle

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

nnorm

cum

ulat

ive

frequ

ency

35%

37%

6 April 20068

Conclusion on NTE lower engine speed limit

• 25th percentile (including idle) is close to the bend of the curve• Increase to 30th percentile is more ‘safe’ while lower limit increase

is only small• Lower limit for 25th percentile excluding idle is higher than 30th

percentile including idle

6 April 20069

II. Methodology for calculating emission contribution

1. Determine the WNTE area for an ‘average’ engine2. Simulate a number of representative cases

(representative vehicle types over representative real-life drivingcycles)

3. Calculate the emission contribution for each part of the enginemap

4. Evaluate the emission contributions in- and outside the controlarea

5. Consider whether an extension of the NTE zone is rationalagainst the emission map

6 April 200610

NOx emission map in [g/h] for average Euro 3

Engine speed (norm.)

Engi

ne to

rque

(nor

m.)Relative NOx emission

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

00

NTE zone

Engine: Euro 3 (average)

6 April 200611

PM emission map in [g/h] for average Euro 3

Engine speed (norm.)

Eng

ine

torq

ue (n

orm

.)Relative PM emission

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

00

NTE zone

Engine: Euro 3 (average)

6 April 200612

Simulated city driving cycle for truck with trailer(second by second)

-0,2

0

0,2

0,4

0,6

0,8

1

1,2

-0,2 0 0,2 0,4 0,6 0,8 1 1,2 1,4

Normalised engine speed

Nor

mal

ised

eng

ine

torq

load pointsNTE zone30% power

Nor

mal

ised

engi

neto

rque

6 April 200613

-0,2-0,1

00,1

0,20,3

0,40,50,6

0,70,8

0,91

1,11,2

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

Normalised engine speed

Nor

mal

ised

eng

ine

torq

load pointsNTE zone30% power

Grid is placed over the engine mapN

orm

alis

eden

gine

torq

ue

6 April 200614

-0,2-0,1

00,1

0,20,3

0,40,50,6

0,70,8

0,91

1,11,2

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

Normalised engine speed

Nor

mal

ised

eng

ine

torq

load pointsNTE zone30% power

Emission contribution per box is calculatedN

orm

alis

eden

gine

torq

ue

Contribution is sum of momentaneous emissionsfor loadpoints in the box

6 April 200615

Engine speed (norm.)

Eng

ine

torq

ue (n

orm

.)

Relative NOx contribution

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

00

NTE zone

Vehicle: Truck with trailerEngine: Euro 3 (average)Driving cycle: CityShifting: Economic/fast

Graphical representation

Engine speed (norm.)

Engi

ne to

rque

(nor

m.)

Relative NOx emission

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

00

NTE zone

Engine: Euro 3 (average)

-0,2-0,1

00,1

0,20,3

0,40,50,6

0,70,8

0,91

1,11,2

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

Normalised engine speed

Nor

mal

ised

eng

ine

torq

load pointsNTE zone30% power

6 April 200616

III. Results for typical cases

Truck with trailer on• Urban road• Rural road• Motorway

City bus on an urban road

Based on (average) Euro 3 emission map

6 April 200617

Results for NOx and PM (truck/trailer in motorway driving)

Engine speed (norm.)

Engi

ne to

rque

(nor

m.)

Relative NOx contribution

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

00

NTE zone

Vehicle: Truck with trailerEngine: Euro 3 (average)Driving cycle: Motorway Shifting: Economic/fast

Engine speed (norm.)

Engi

ne to

rque

(nor

m.)

Relative PM contribution

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

00

NTE zone

Vehicle: Truck with trailerEngine: Euro 3 (average)Driving cycle: MotorwayShifting: Economic/fast

6 April 200618

Results for NOx and PM (truck/trailer in city driving)

Engine speed (norm.)

Eng

ine

torq

ue (n

orm

.)

Relative NOx contribution

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

00

NTE zone

Vehicle: Truck with trailerEngine: Euro 3 (average)Driving cycle: CityShifting: Economic/fast

Engine speed (norm.)

Eng

ine

torq

ue (n

orm

.)

Relative PM contribution

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

00

NTE zone

Vehicle: Truck with trailerEngine: Euro 3 (average)Driving cycle: CityShifting: Economic/fast

• Carve-out below 30% power excludes a high emission contribution area (for this particular case)

• Emission contribution in carve-out for PM is rather low

6 April 200619

Results for different cases

0

10

20

30

40

50

60

70

80

90

truck and trailer(city)

truck and trailer(rural)

truck and trailer(motorway)

urban bus (city)

[%] Share in NTE zone

NOx contributionPM contribution

0

5

10

15

20

25

30

truck and trailer(city)

truck and trailer(rural)

truck and trailer(motorway)

urban bus (city)[%

] Idle shareNOx contributionPM contribution

NTE zone contribution(excl. 30 sec. interval) Idle contribution

NTE share could be increased by a larger NTE zone

6 April 200620

Relative NOx emission [g/kWh]

Engine speed (norm.)Engine torque (norm.)

-0.20.0

0.20.4

0.60.8

1.01.2

-0.20.0

0.20.4

0.60.8

1.0

0.2

0.4

0.6

0.8

1.0

Engine: Euro 3 (average)

6 April 200621

Relative NOx emission [g/kWh]

Engine speed (norm.)Engine torque (norm.)

Relative NOx emission (normalised g/kWh)no

rmal

ised

eng

ine

torq

ue

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

normalised engine speed0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2

Engine: Euro 3 (average)

6 April 200622

Preliminary conclusions

• Time share of engine operation in NTE zone rather low• Emission contribution in NTE zone is considerably higher• Emission contribution of idle operation is comparatively low• Carve-out below 30% power excludes a high emission contribution

area (depending on the vehicle application)• Carve out for PM seems unnecessary

BUT: this is only concluded on a limited dataset. Further research is needed and will be executed during a study for DG Enterprise

6 April 200623

IV. Further steps: WNTE evaluation for DG Enterprise

Purpose: to appraise the suitability to European engines and driving conditions of the draft WNTE control zone concept (OCE GTR)

Funded from the DG-ENT framework contract on “Economic and technical assistance in relation to the emission of environmental pollutants from automobiles”

Project team:• TNO Automotive (NL)• TÜV Nord (D)• TU Graz (A)• EMPA (CH)

6 April 200624

Project scope

TASK 1 – Assessment of WNTE concept in current GTR

• Existing driving patterns data for representative categories of vehicle type and application (from WHDC database)

• Simulation of PM and NOx emissions per category using current PHEM model (Euro 3 engine map)

• Graphical presentation of emissions in/outside the NTE control zone

6 April 200625

Project scope

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Time [s] Positive Engine Work[kWh]

Cumulated emissions(with 30 seconds rule) [g]

Cumulated emissions(without 30 seconds rule)

[g]

within WNTE zone outside WNTE zone

Output of Task 1:• Timeshare in/outside the NTE control zone• Positive work in/outside the NTE control zone• Emissions in/outside the NTE control zone• Effect of interval length on these shares of time/work/emissions

6 April 200626

Project scope

TASK 2 – Assessment of NTE concept for future HD engines

Based on:• Limited amount of existing data for Euro 4/5 engines (quantitative)• Expert views on Euro 5/6 engines behaviour/calibration (qualitative)

Resulting in:• Identifying possible limitations in NTE zone proposal

TASK 3 – Review of the effectiveness of WHDC and WNTE concepts as a whole

• Coverage of ‘higher risk’ areas • Elimination of defeat devices and/or irrational control strategies• Identifying possible limitations

6 April 200627

Project scopeTASK 4 – Consider rationale for improving NTE definitions:• Changing engine speed limit of NTE zone• Review of carve outs (e.g. 30% power, PM carve out)• 30 seconds interval• Review of compliance factor (1.25, 1.5 or other)

TASK 5 – Assessment of ambient temperature and pressure boundaries• Analysis of existing on-road measurements• Expert view for future engine technology

TASK 6 – Review of alternative NTE conceptsIncluding (but not limited to):• Work-based window• Compliance factor (based on BSFC instead of torque)

6 April 200628

6 April 200629

Results for NOx and PM (truck/trailer in rural driving)

Engine speed (norm.)

Engi

ne to

rque

(nor

m.)

Relative NOx contribution

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

00

NTE zone

Vehicle: Truck with trailerEngine: Euro 3 (average)Driving cycle: RuralShifting: Economic/fast

Engine speed (norm.)

Engi

ne to

rque

(nor

m.)

Relative PM contribution

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

00

NTE zone

Vehicle: Truck with trailerEngine: Euro 3 (average)Driving cycle: RuralShifting: Economic/fast

6 April 200630

Results for NOx and PM (city bus in urban driving)

Engine speed (norm.)

Eng

ine

torq

ue (n

orm

.)

Relative NOx contribution

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

00

NTE zone

Vehicle: City busEngine: Euro 3 (average)Driving cycle: City Shifting: Economic/fast

Engine speed (norm.)

Eng

ine

torq

ue (n

orm

.)

Relative PM contribution

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4

00

NTE zone

Vehicle: City BusEngine: Euro 3 (average)Driving cycle: CityShifting: Economic/fast