Comparing unit emissions from on-road remote sensing with HBEFA

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1 Comparing unit emissions from on-road remote sensing with HBEFA Dr. Jens Borken-Kleefeld International Institute for Applied Systems Analysis (IIASA) Mitigation of Air Pollutants and Greenhouse Gases Program Laxenburg/Austria Acknowledgements: The provision of remote sensing data by AWEL, Baudirektion Zürich (Gian-Marco Alt), funding from INFRAS Bern (Mario Keller), BAFU Bern (Harald Jenk), the ICCT (Kate Blumberg), and collaboration with TU Graz (St. Hausberger, M. Rexeis) and Yuche Chen (now Texas TTI)

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3 FC [g/km] vs. avg. speed for 1 diesel car NO x [g/km] vs. avg. speed for 1 diesel car

4 Routine remote sensing site at Zurich/Switzerland Extra-urban site in Zurich conurbation 9% uphill grade, after 1.5 km ride through forest Preconditioned hot ~5 000 veh/day one direction Measurements started late 1990 ies Goetsch, AWEL ZH 2013

5 On-road vehicle emission remote sensing Zurich/CH data overview Avg. speed: 46 km/h (20-56) Avg. accel.: 1.2 m/s 2 ( ) incl. 9% uphill grade Engine load ~ highway driving! ~ valid records Increasing share of diesel cars! Chen & Borken-Kleefeld, AtmEnv. 88 (2014)

6 NO x emissions on-road Limits: diesel On-road diesel On-road remote sensing (here Zurich/CH, 9% uphill): Gasoline cars follow emission limit development (though very different cycle) Diesel cars: NO x even higher now than 20 years ago, no correlation with limits. Chen & Borken-Kleefeld, AtmEnv. 88 (2014)

7 NO x emissions on-road 95 th gasoline 95 th diesel On-road diesel On-road remote sensing (here Zurich/CH, 9% uphill): Gasoline cars follow emission limit development (though very different cycle) Diesel cars: NO x even higher now than 20 years ago, no correlation with limits. 95 th percentile: Gasoline cars >15 yrs problem Diesel: Problem by design Chen & Borken-Kleefeld, AtmEnv. 88 (2014)

8 NO x emissions: On-road vs. HBEFA for cars For meaningful comparison account for different engine loads, different mean vehicle ages, different manufacturer mix. For highway driving HBEFA ~ RS Zurich. But urban London should be at much lower level!? London: Carslaw & Rhys-Tyler, AtmEnv (2013) Zurich: Chen & Borken-Kleefeld, AtmEnv. 88 (2014) HBEFA/PHEM: Hausberger, Rexeis et al. (2009)

9 NO x emissions: Correlation over engine load Comparing Instantaneous on-road vehicle kinetic power with cycle averaged PHEM modeled engine power Surprisingly close correlation engine power key for emissions of diesel Euro 4 (and Euro 2) cars Different for Euro 3 & 5 cars

10 Similar load effect for diesel cars in London (Carslaw & Rhys-Tyler 2013) Roughly linear increase between 5-20 kw/t VSP Differences in level and slope by engine size (<2 l/>2 l)

11 Share NO 2 decreases with load for diesel cars (Carslaw & Rhys-Tyler 2013) Different NO 2 share by engine size (<2 l/>2 l) NO 2 shares slightly decrease with load We and HBEFA use one constant NO 2 share for all engine size and loads

12 NO x emissions: On-road vs. HBEFA for LCV HBEFA ok for Euro 3-5 LCV Old LCV not ok, hence trend wrong LCV like diesel cars, not like limit values.

13 Emissions over engine load NO x -PM conflict for low-emission zones LCV NOx LCV - Opacity Euro 1 always low, Euro 5 always high NO x (also in urban driving) Euro 1 always highest, Euro 5 always lowest PM robust over whole load range

14 HBEFA = average fleet in Europe? NO x diesel cars NO (x) emissions vary ±30% between manufacturers No manufacturer within NEDC limit Fleets with high share of D7 average D3, D11 or D12 low French fleet high or low or average? German fleet

15 HBEFA = average fleet in Europe? Opacity diesel cars Opacity varies -60%/+50% between manufacturers Fleets with high share of D7 averagelow D3D8, D9, D11, D12 low French fleet high or low or average? German fleet

16 Best manufacturers manage low PM and low NO x emissions Diesel cars by manufacturer Strong reduction of PM does not compromise on NO (x) emissions Reduction efforts deliberate choice by individual manufacturer Why not require BEST AVAILABLE TECHNOLOGY? Caveat: No direct NO 2 measurements here

17 Perspectives NO 2 PM 10/2.5 Vehicle categories Heavy-duty trucks & buses, OLD gasoline cars, DIESEL cars Heavy-duty trucks & buses, DIESEL cars Control requirement Target HDV (+ diesel LDV) Need NO+NO 2 Need PM 2.5 emissions. Clear relation with RS opacity? Target HDV (+ diesel LDV)! Abrasion, brake, tyre possible? Focus remote sensing on dedicated tasks!? Monitoring emissions from fleet and specific vehicles & technologies Large sample in short time, flexible locations fleet coverage Great for research applications, e.g. Deterioration factors, validation of emission factors,

18 Further reading Reports on the RS campaigns in Zurich/CH (in German) -> -> Luft -> Verkehr -> Abgasmessung RSD Borken-Kleefeld: Guidance document on Vehicle Remote Sensing -> -> Publications -> Remote sensing Chen & Borken-Kleefeld: Real-driving emissions from cars and light commercial vehicles e Results from 13 years remote sensing at Zurich/CH. Atmospheric Environment 88 (2014) For more information contact: borken@iiasa.ac.at