We have used rectangular CO-ordinates that enable us to indicate the completness of destructive combustion. The ordinate y designates oxygen consumed and the abscissa X, (Ψ-0.5)(CO)+Ψ(CO₂)-0.5 (H₂) in % respectively. Ψ can be any real number, but Kennzahl des Brennstoffes σ₀ or unit is-useful. When Ψ equals σ₀, the perfect combustion gases are plotted on the straight line y=(tanα)X and tanα is unit. But the combustion. gases of the partial light elements of the fuel have tanα and in this case tanα is not unit, but it is to a relation 1<tanα<∞, while tanα of the heavy elements is in a relation 1>tanα>0. The more a destructive combution is incomplete, the more tanα of the light elements increases and on the other hand that of heavy compornents decreses. By this way we can compare the combustion degrees in the pre-combustion chamber with the turbulent chamber and the direct injection chamber. In the pre-combution chamber the contents of CO and H₂ are more than that of CO₂, but in the other typtcal chamber only 1ittle quantities of CO and H₂ are found.