1. NO2 Measurement Method
proposed by Japan
9 ~ 10 December 2010

2. Current concerns on NO2 measurement
Concentration for emission system comply with Euro5 or 6
Refer WLTP-DTP-02-06

3. Proposed method based on WLTP-DTP-02-06
<Modal Method>
NO2(ppm)=
CVS-Bag_NOx(ppm) – diluted exhaust NO average(ppm)

4. Counter Proposal by Japan
Apply current measurement method (=CVS-Bag method)
then, analyze NOx/NO respectively
<CVS-Bag Method>
NOx/NO
No modal measurement of NO
from diluted exhaust is necessary

5. NO -> NO2 reaction ratio
NO2 reaction ratio is less than 2% when NO concentration in Bag is less than 4 ppm (=equivalent Euro 5 or 6 level) 3
Test results
(measured by CLD) ●
2.5
*: average CVS 12m3/min 2
Theoretical line of
NO->NO2 reaction ratio
D-Euro6*
NO -> NO2 reaction ratio
in Bag after 15 min. (%)
G-Euro5,6*
1.5 1
D-Euro5*
0.5 1 2 3 4 5 6
Bag-NO Concentration (ppm)

6. Test Results Comparison (NO, NO2)
No significant difference is observed
between CVS-Bag method and Modal method
Petrol vehicle (NEDC Total : NOx 0.049g/km) 3
NO2
Concentration
(ppm) 2 1 NO
NO2=0.02
NO2=0.00
CVS-Bag
Modal
CVS-Bag
Modal
NEDC_Part1
NEDC_Part2
Diesel vehicle (NEDC Total : NOx 0.174g/km) 6 5
NO2 4
Concentration
(ppm) 3 NO
NO2=0.07
NO2=0.04 2 1
CVS-Bag
Modal
CVS-Bag
Modal
NEDC_Part1
NEDC_Part2

7. Test-to-Test Variability (NO)
Nearly identical for both average and variability level
Petrol vehicle (NEDC Total : NOx 0.049g/km) 1 5
NEDC_Part1 (n=9)
NEDC_Part2 (n=9)
0.8 4
･2σ/:17.5%
･Ave.:0.50
･2σ/:20.4%
･Ave.:0.52
･2σ/:27.2%
･Ave.:2.62
･2σ/:30.1%
･Ave.:2.75
0.6 3
NO concentration (ppm)
NO concentration (ppm)
0.4 2
0.2 1
CVS-Bag
Modal
CVS-Bag
Modal

8. Summary
Recent study in Japan indicates no significant difference between CVS-bag method and proposed method for NO2 measurement.
It’s not right timing to eliminate the currently well recognized method without knowing the applicability under the new test cycle and new test procedure.
Once new cycle and new test procedure are available, Japan will evaluate the measurement methods again from the view points of measurement precision, applicability, investment and so on, then report it to this group for final decision.