Directive 2005/55/EC of the European Parliament and of the Council (repealed)Show full title

4. λ-SHIFT FACTOR (S_λ)

4.1. Calculation of the λ-shift factor (S_λ)(1)

where:

S_λ

=

λ-shift factor;

inert %

=

% by volume of inert gases in the fuel (i.e. N₂, CO₂, He, etc.);

O₂ ^*

=

% by volume of original oxygen in the fuel;

n and m

=

refer to average C_nH_m representing the fuel hydrocarbons, i.e:

where:

CH₄

=

% by volume of methane in the fuel;

C₂

=

% by volume of all C₂ hydrocarbons (e.g. C₂H₆, C₂H₄, etc.) in the fuel;

C₃

=

% by volume of all C₃ hydrocarbons (e.g. C₃H₈, C₃H₆, etc.) in the fuel;

C₄

=

% by volume of all C₄ hydrocarbons (e.g. C₄H₁₀, C₄H₈, etc.) in the fuel

C₅

=

% by volume of all C₅ hydrocarbons (e.g. C₅H₁₂, C₅H₁₀, etc.) in the fuel;

diluent

=

% by volume of dilution gases in the fuel (i.e. O₂ ^*, N₂, CO₂, He etc.).

4.2. Examples for the calculation of the λ-shift factor S_λ

Example 1: G₂₅: CH₄ = 86 %, N₂ = 14 % (by volume)

Example 2: GR: CH₄ = 87 %, C₂H₆ = 13 % (by vol)

Example 3: USA: CH₄ = 89 %, C₂H₆ = 4,5 %, C₃H₈ = 2,3 %, C₆H₁₄ = 0,2 %, O₂ = 0,6 %, N₂ = 4 %

(1)

Stoichiometric Air/Fuel ratios of automotive fuels - SAE J1829, June 1987. John B. Heywood, Internal combustion engine fundamentals, McGraw-Hill, 1988, Chapter 3.4 ‘Combustion stoichiometry’ (pp. 68 to 72).