The equation or formula for the calculation of the air-fuel equivalence ratio λ of air-fuel mixtures presented in this paper is an extension of the already very comprehensive λ - equation which was published earlier. In that former version the quantities carbon, hydrogen, oxygen, and water in the fuel, water vapor in the air, and carbon dioxide, carbon monoxide, oxygen, unburned hydrocarbons, and nitrogen oxides as the main components of the exhaust-gas are considered. In the present extended version of the equation additional quantities are included: the sulfur in the fuel, a possibly occurring and measurable engine oil consumption, the sulfur oxides and hydrogen sulfide in the exhaust-gas, as well as the carbon, hydrogen, oxygen, and sulfur from the particulate emissions, and furthermore the exhaust-gas components methane, methanol, formaldehyde, and ammonia which were introduced into the ISO-Standard 8178-1. The mentioned particulate emissions are taken as particulate emission mass fractions and are then mathematically converted into concentrations, given in volume fractions, which can be used in the equation.