1 wltp open issue phase 1b issue: fuel consumption interpolation method. acea informal document...
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1
WLTP Open Issue Phase 1B
Issue: Fuel Consumption interpolation method
.
ACEA Informal Document 09.09.2014
WLTP-08-08e
2
Background:Currently, there is only an interpolation method for CO2 in the
GTR. Individual FC values are requested by several contracting parties.
Proposal:Interpolation of the worst and best case FC values.
Rationale:The calculation of FC values is based on the carbon balance. The influence of HC and CO is rather low. Therefore, when interpolating the best case and the worst case FC values, the possible error for the determination of intermediate values is little.
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0
0.01
0.02
0.03
0.04
0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
5641 5778 5791 5915 6005 6064 6108 6108 6245 6279 6279 6381 6381
HC
[g/k
m]
CO
[g/k
m]
Energy [kJ]
CO
HC
NEDC test series
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Energy best case Energy worst case
Worst case THC ≠ worst case CO ≠ worst case Energy
Example (NEDC): Light duty vehicle, Automatic gearbox, curb mass 4250 - 4750 lbs Measured at different energy levels
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0
0.01
0.02
0.03
0.04
0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
5641 5778 5791 5915 6005 6064 6108 6108 6245 6279 6279 6381 6381
HC
[g/k
m]
CO
[g/k
m]
Energy [kJ]
CO
HC
NEDC test series with Interpolation Points
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Energy best case Energy worst case
Worst case THC ≠ worst case CO ≠ worst case Energy
Example (NEDC): Light duty vehicle, Automatic gearbox, curb mass 4250 - 4750 lbs Measured at different energy levels
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Influence of HC and CO on Fuel Consumption
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Interpolation between best an worst case shows a very good correlation
With CO2 = 0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.05
5600 5700 5800 5900 6000 6100 6200 6300 6400 6500
FC
[l/1
00
km
]
Energy [kJ]
best case
worst case
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Influence of HC and CO on Fuel Consumption
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-0.0070
-0.0050
-0.0030
-0.0010
0.0010
0.0030
0.0050
0.0070
5641 5778 5791 5915 6005 6064 6108 6108 6245 6279 6279 6381
ma
x d
evi
ati
on
[l/1
00
km
]
Energy [kJ]-0.100
-0.080
-0.060
-0.040
-0.020
0.000
0.020
0.040
0.060
0.080
0.100
5641 5778 5791 5915 6005 6064 6108 6108 6245 6279 6279 6381
ma
x d
evi
ati
on
[%]
Energy [kJ]
Maximum influence of interpolation due to HC and CO contribution is lower than 0.06 % of fuel consumption value in this example (~ 8 l/100 km)
FC ~ 8 l/100 km
Difference between measured and interpolated values
1. liters per 100 km 2. percentage
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Proposal for gtr 15
3.2.3.2.2.7
. Calculation of the FC value for an individual vehicle by the energy interpolation method
For each cycle phase p of the WLTC applicable for individual vehicles in the CO2 vehicle family, the contribution to the FC for the individual vehicle shall be calculated as follows:
FCind,p = FCL,p +ቆE3,p − E1,pE2,p − E1,pቇ× ൫FCH,p −FCL,p൯
(42)
The FC attributed to the individual vehicle of the CO2 vehicle family FCind shall be calculated by the following equation:
FCind = σ FCind,p × dc,pp σ dc,pp
(43)
for all of the applicable cycle phases p.
All abbreviations according to Annex 7