Division 2.1.6.3 Air flow and air to fuel ratio measurement method

United Kingdom

This involves exhaust gas mass calculation from the air flow and the air to fuel ratio. The instantaneous exhaust gas mass flow q _mew, _i [kg/s] shall be calculated by means of equation (7-17):

q_{m ew, i} = q_{m aw, i} \times (1 + \frac{1}{A ∕ F_{st} \times λ_{i}})

(7-17)

with:

A ∕ F_{st} = \frac{138,0 \times (1 + \frac{α}{4} - \frac{ε}{2} + γ)}{12,011 + 1,00794 \times α + 15,9994 \times ε + 14,0067 \times δ + 32,065 \times γ}

(7-18)

λ_{i} = \frac{(100 - \frac{c_{COd} \times 10^{- 4}}{2} - c_{HCw} \times 10^{- 4}) + (\frac{α}{4} \times \frac{1 - \frac{2 \times c_{COd} \times 10^{- 4}}{3,5 \times c_{CO2d}}}{1 + \frac{c_{COd} \times 10^{- 4}}{3,5 \times c_{CO2d}}} - \frac{ε}{2} - \frac{δ}{2}) \times (c_{CO2d} + c_{COd} \times 10^{- 4})}{4,764 \times (1 + \frac{α}{4} - \frac{ε}{2} + γ) \times (c_{CO2d} + c_{COd} \times 10^{- 4} + c_{HCw} \times 10^{- 4})}

(7-19)

where:

q_m _aw, _i

wet intake air mass flow rate [kg/s]

A/F _st

stoichiometric air-to-fuel ratio [-]

λ_i

instantaneous excess air ratio [-]

c _COd

concentration of CO in the raw exhaust gas on a dry basis [ppm]

c _CO2d

concentration of CO₂ in the raw exhaust gas on a dry basis [per cent]

c _HCw

concentration of HC in the raw exhaust gas on a wet basis [ppm C1]

molar hydrogen-to-carbon ratio [-]

molar nitrogen-to-carbon ratio [-]

molar oxygen-to-carbon ratio [-]

atomic sulphur-to-carbon ratio [-]

Notes on Division 2.1

Textual amendments

F1: Substituted by Commission Delegated Regulation (EU) 2018/989 of 18 May 2018 amending and correcting Delegated Regulation (EU) 2017/654 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery (Text with EEA relevance).