WLTP-07-12e
WLTP
Open Issue Phase 1B
Issue: Generic formula for hydrocarbon density
JAPAN Informal Document 27.05.2014
.
1
Counter-Proposal by
It would be better to have generic formula for all fuel dependent coefficients
(HC densities, dilution factors, fuel consumption, Willans factors), however, it
is acceptable to add generic formula for HC densities with clarification of its
EU registration
Generic formula
usage to avoid unnecessary confusion. for petrol (E10) ρ=0.645 g/1
0.646
for diesel (B5)
for diesel (B7)
ρ=0.622 g/1
ρ=0.623 g/1
0.623
0.625
1. Add specific densities for E10 and B7 into section3.1.2. of Annex 7
(same as EU registration)
2. Add section 3.1.2.2. of Annex 7 with slight modification.
3. Modify section 3.2.1.1.1. and 3.2.1.1.2. of Annex 7
3. Need experts input for Willans factors for E10 and B7 (Annex6/Appendix2)
4. In case of new reference fuel, the following sections need to be amended
(1) Annex6/Appendix2
(2) Annex7 Section 3.1.2., 3.2.1.1.1. and 6
2
Annex 7
3.1.2.1. The mass M of gaseous compounds emitted by the vehicle during the test shall be determined by obtaining the
product of the volumetric concentration of the gas in question and the volume of the diluted exhaust gas with due regard
for the following densities under the reference conditions of 273.15 K and 101.325 kPa:
Carbon monoxide (CO) ρ=1.25g/l
Carbon dioxide (CO2) ρ=1.964 g/l
Hydrocarbons:
for petrol (E0) (C1H1.85) ρ=0.619 g/1
for petrol (E5) (C1H1.89O0.016) ρ=0.631 g/1
for petrol (E10) (C1H1.93O0.033) ρ=0.645 g/1
for diesel (B0) (C1Hl.86) ρ=0.619 g/1
for diesel (B5) (C1Hl.86O0.005) ρ=0.622 g/1
for diesel (B7) (C1Hl.86O0.007) ρ=0.623 g/1 g/1
for LPG (C1H2.525) ρ=0.649 g/l
for NG/biomethane (CH4) ρ=0.714 g/l
for ethanol (E85) (C1H2,74O0.385) ρ=0.932 g/l
Nitrogen oxides (NOx) ρ=2.05 g/1
Nitrogen dioxide (NO2) ρ=2.05 g/1
Nitrous oxide (N2O) ρ=1.964 g/1
The density for NMHC mass calculations shall be equal to that of total hydrocarbons at 273.15 K and 101.325 kPa and is
fuel-dependent.
3.1.2.2. In case the specific density is not available in section 3.1.2.1, general equation for the hydrocarbons
densities (ρ) for each reference fuel with an average composition of CxHyOz is:
𝐠
𝐠
𝐠
𝐇
𝐎
𝐌𝐖𝐂
+ × 𝐌𝐖𝐇
+ × 𝐌𝐖𝐎 [
]
𝐂
𝐂
𝐦𝐨𝐥
𝐦𝐨𝐥
𝐦𝐨𝐥
𝛒𝐇𝐂 =
𝐥
𝐕𝐌 [
]
𝐦𝐨𝐥
ρHC: density of total hydrocarbons [g/l]
MWC: molecular weight of carbon = 12.011 g/mol
MWH: molecular weight of hydrogen = 1.008 g/mol
MWO: molecular weight of oxygen = 15.999 g/mol
VM: molar volume for an ideal gas at 0°C and 101.325 kPa = 22.413 l/mol
H/C: ratio of hydrogen to carbon for a specific fuel CxHyOz
O/C: ratio of oxygen to carbon for a specific fuel CxHyO
3
3.2.1.1.1. The dilution factor, DF, is calculated as follows:
13.4
for petrol (E0, E5 and E10) and diesel(B0)
13.5
for diesel (B5 and B7)
for LPG
for NG/biomethane
for ethanol (E85)
(5a)
(5b)
(5c)
(5d)
(5e)
3.2.1.1.2. In case difference fuel other than listed in section 3.2.1.1.1. general equation for the dilution
6. Calculation of fuel consumption
Is general equation for fuel consumption calculation available ?
6.11. For a vehicle with a positive ignition engine fuelled with ethanol (E85)
“(0.273 *)” shall be “(0.273 * CO2)”
Annex 6 -Appendix 2
4
Add E10 and B7 but no idea for these Willans factors.
Is general equation for Willans factors available ?