<P> The presence of oxygen in the exhaust gases indicates that the combustion of the mixture was not perfect, resulting in contaminant gases . Thus measuring the proportion of oxygen in the exhaust gases of these engines can monitor and measure these emissions . This measurement is performed in the MOT test through Lambda coefficient measurement . </P> <P> The Lambda coefficient (λ) is obtained from the relationship between air and gasoline involved in combustion of the mixture . It is a measure of the efficiency of the gasoline engine by measuring the percentage of oxygen in the exhaust . </P> <P> When gasoline engines operate with a stoichiometric mixture of 14.7: 1 the value of LAMBDA (λ) is "1". </P> <P> Mixing ratio = weight of fuel / weight of air </P>

When is it necessary to analyse the exhaust gases of an internal combustion engine