meso + micro real driving emission models for aimsun

14th Annual Aimsun Users’ Meeting

MESO and MICROReal Driving Emission models for AIMSUN

Dr James TateInstitute for Transport Studies,

University of Leeds, UKEmail: [email protected]

Twitter: drjamestate

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mailto:[email protected]


#DIESELGATENOX common marques & modelsOctober 2015

Euro Standard

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Euro 3 Euro 4 Euro 5

BMW FORD


LANDROVER MERCEDES


PEUGEOT SKODA


VAUXHALL VOLKSWAGEN


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EMISSION MODELLING WITH AIMSUN▶ Calibrated & Validated Network▶ Set ‘realistic’ UK vehicle dynamics▶ Harvest ALL trajectories▶ Manipulate into emission model format (1Hz)▶ Instantaneous Emission Modelling e.g. PHEM

BEST PRACTICE


CHALLENGES• AVERAGE SPEED (MESO) EMISSION MODELS LIMITATIONS

– Most commonly applied emission model e.g. COPERT, HBEFA, EFT (UK)

– Under-predict emissions at low-speeds

– As ‘average’ uncertainties increase for shorter links

• EMISSION MODELS IN TRAFFIC SIMUATION SOFTWARE OFTEN DATED

• EXTERNAL INSTANTANEOUS EMISSION MODELS (IEM) CUMBERSOME

SOLUTIONS• NEW TYPE OF AVERAGE SPEED EMISSION MODEL FOR THE EU FLEET

• NEW SIMPLE (FAST) IEM IMPLEMENTED WITHIN AIMSUN (API)

– 1hz time step

– Limited range of vehicle types & categories e.g. Euro 5 diésel car, LGV, HGV


UNDER-PINNING DATATaking the road into the LaboratoryThe London Drive Cycle & Emission Testing (TfL)

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https://www.london.gov.uk/sites/default/files/In-service%20emissions%20performance%20of%20Euro%206VI%20vehicles%20WEBSITE%20COPY.pdf


TfL EURO 6 / VI LABORATORY TESTING

12 PASSENGER CARS: tested over the entire LDC (140 kms)

▶ Powertrains | petrol (2), diesel (9) and petrol-HEV (1);

▶ Exhaust after-treatments | 3 way Cat, LNT and SCR;

▶ Market segments | Compact, Supermini, Small family, Family/MPV, SUV/4x4,Prestige/sports and Hybrid; and

▶ Marques | BMW, Fiat, Lexus, Mercedes, Peugeot, Volvo and Volkswagen.

3 HEAVY-GOODS VEHICLES: tested over the suburban sub-cycles only

▶ Rigid HGV N2 7500kg

▶ Rigid HGV N3 18000kg

▶ Artic HGV N3 40000kg

▶ LADEN and UN-LADEN

7

1 Millbrook Vehicle Emission testing laboratories that meet therequirements of Directive 2007/46 EC Article 41, Section 3and have been designated as a Category A Technical Servicefor Individual Vehicle Approvals (IVA).


LIMITATIONSAverage speed Emission Models▶ Analysis of Laboratory Testing data▶ Uncertainties greater on short links


TfL EURO 6 PASSENGER CAR RESULTS

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Euro 5b/b+ diesel limit

Euro 6b/c diesel limit

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CompactPrestige/sports

Small familySmall family

Family/MPV

Family/MPV

Small familySUV/4x4

Supermini

Prestige/sports

Family/MPV

Moody, A., Tate, J. 2016. In service CO2 and NOX emissions of Euro 6/VI cars, light- and heavy-duty goods vehicles in real London driving:Taking the road into the Laboratory. The 21st International Transport and Air Pollution (TAP) Conference, Lyon, France, May 24-26, 2016.


* Zallinger, M., Tate, J., and Hausberger, S. 2008. An instantaneous emission model for the passenger car fleet.Transport and Air Pollution conference, Graz 2008

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UNDER-PINNING MODELInstantaneous Emission Model PHEM*Passenger car and Heavy-duty Emission Model

Verification & Validation


NEW TYPE OF AVERAGE SPEEDEMISSION MODEL

• Basis ‘MICRO-trips’: Stationary Speed > 5 km.h-1 Stationary

• Regression relationships (in ‘R’) fitted to each ‘MICRO-trip’average-speed & Emission Rate

9000 9200 9400 9600 9800 10000

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• Example Euro 5 diesel car | 401 London Drive Cycle ‘Micro-trips’

CO2 NOX

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PASSENGER CARS


NEW TYPE OF AVERAGE SPEEDEMISSION MODEL (EM)

Coloured line : TfL EMGrey : COPERTDotted : Standard


NEW TYPE OF AVERAGESPEED EMISSION MODEL

London Real Driving Trajectory datai.e. configured for local driving conditions FOR EACH vehicle type


The ‘London Taxi’ (LTI)

Also: Van, Truck, Bus, Coach



• Process


WORK IN PROGRESS

STEP 1. Emission Functions being applied to London fleet + traffic movement data

▶ Observed and Modelled link flows & speeds

▶ Hourly resolution

STEP 2. Input for London air pollution dispersión simulations (Autumn 2016)

EXPECTED OUTCOMES

• Higher emissions predicted across Central London, accounting for:

▶ Traffic congestion especially in peak periods

▶ Fleet mix (high proportion of Taxis, Buses and Trucks)

• Closer agreement between MEASURED and MODELLED levels of air pollution

NEW AVERAGE SPEED LONDON EMISSION MODEL


• NEW generation of IEMs derived from PEMS (Portable Emission MeasurementSystems) and Remote Sensing data i.e. semi-empirical

• Formulation Vehicle Specific Power (VSP)

– Accounts for power demands: Acceleration (a), Road gradient (⍬), Rolling resistance andAerodynamic drag (from speed v). Units kW.ton-1

• E.g. Basis of the US ‘MOVES’ IEM

• European Model* developed from TNO’s growing database of PEMS testingdata (now 1,000s passenger cars)

• Currently implemented in AIMSUN API (FP7 ecoDriver Project)

Fast, Simple Instantaneous Emission Models

* Ligterink, N., Tate, J. Heijne, V. 2016. Vehicle emission model for traffic simulations. The 21st International Transport and Air Pollution (TAP)Conference, Lyon, France, May 24-26, 2016.


Fast, Simple Instantaneous Emission Model

e.g. Verification of Euro 5 diesel car OBSERVED vs. MODELLED (blue CO2

& red NOX) with TfL London Drive Cycle data (extract)

Ligterink, N., Tate, J. Heijne, V. 1 2016. Vehicle emission model for traffic simulations. The 21st International Transport and Air Pollution (TAP)Conference, Lyon, France, May 24-26, 2016.


Fast, Simple Instantaneous Emission Models

e.g. Verification of Euro 5 diesel truck (18t Rigid HGV) OBSERVED vs. MODELLED(blue CO2 & red NOX) with TfL London Drive Cycle data (extract)

Ligterink, N., Tate, J. Heijne, V. 1 2016. Vehicle emission model for traffic simulations. The 21st International Transport and Air Pollution (TAP)Conference, Lyon, France, May 24-26, 2016.


SUMMARY

• New MESO emission model (Average Speed)

+ Reliable predictions for short links

+ Reliable predictions for low driving speeds

+ Simple, consistent function form

+ Whole European fleet old & new, petrol & diésel

+ Up-to-date (includes the very latest Euro 6c diésel cars)

• New MICRO (instantaneous) emission model

+ Reliable predictions for Euro 5 / V vehicles

+ Expect up-dates for Euro 6 / VI

+ Fast computation

+ Evaluation of traffic management policies (relative change)


MESO and MICROReal Driving Emission models for AIMSUN

Dr James TateInstitute for Transport Studies,

University of Leeds, UKEmail: [email protected]

Twitter: drjamestate

0 20 40 60 80

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Speed (km.h1

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mailto:[email protected]

meso + micro real driving emission models for aimsun

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