The Method of Measuring Air-Fuel Ratio by Radical Luminescence in High Combustion Pressure

The relations of luminous intensity of the radicals, CH, C₂, and OH radical, and the equivalence ratio, ϕ under high combustion pressure region (7.0MPa maximum) were investigated. Luminous intensity of each radical and combustion pressure were experimentally obtained using a constant volume combustion chamber. It was found that luminous intensity of each radical can be expressed as a function of ϕ and the combustion pressure. The estimation of ϕ was done within the region, 0.8<ϕ<1.2 and 2.0MPa<P<7.0MPa using the ratio of luminous intensity of CH and C₂ radical, and combustion pressure. The value of ϕ was estimated and compared with the actual value; the accuracy was about ±5.0%.