Division 3.8 F1

The second subparagraph of paragraph 1.3 of Appendix 8 to Annex 4 shall be understood as:

‘ … The dilution factor is calculated as follows:

• For each reference fuel, except hydrogen

  $\mathrm{DF}=\frac{X}{C_{\mathrm{CO2}}+\left(C_{\mathrm{HC}}+C_{\mathrm{CO}}\right)\times {10}^{-4}}$

• For a fuel of composition CxHyOz, the general formula is:

  $X=100\frac{x}{x+\frac{y}{2}+\mathrm{3,76}\times \left(x+\frac{y}{4}-\frac{z}{2}\right)}$

• In particular for H2NG, the formula is:

  $X=\frac{\mathrm{65,4}\times A}{\mathrm{4,922A}+\mathrm{195,84}}$

• For hydrogen, the dilution factor is calculated as follows:

  $\mathrm{DF}=\frac{X}{C_{\mathrm{H2O}}-C_{\mathrm{H2O}-\mathrm{DA}}+C_{\mathrm{H2}}\times {10}^{-4}}$

• For the reference fuels contained in Annex IX, the values of “ X ” are as follows:

  F2Fuel	X
  Petrol (E5)	13,4
  Petrol (E10)	13,4
  Diesel (B5)	13,5
  Diesel (B7)	13,5
  LPG	11,9
  NG/biomethane	9,5
  Ethanol (E85)	12,5
  Ethanol (E75)	12,7

In these equations:

C _CO2

concentration of CO ₂ in the diluted exhaust gas contained in the sampling bag, expressed in per cent volume,

C _HC

concentration of HC in the diluted exhaust gas contained in the sampling bag, expressed in ppm carbon equivalent,

C _CO

concentration of CO in the diluted exhaust gas contained in the sampling bag, expressed in ppm,

C _H2O

concentration of H ₂ O in the diluted exhaust gas contained in the sampling bag, expressed in per cent volume,

C _H2O-DA

concentration of H ₂ O in the air used for dilution, expressed in per cent volume,

C _H2

concentration of hydrogen in the diluted exhaust gas contained in the sampling bag, expressed in ppm,

A

quantity of NG/biomethane within the H2NG mixture, expressed in per cent volume ’ .