FIELD: manufacture of engines. SUBSTANCE: first and second reference fuels having different octane numbers of detonation and tested fuel having unknown octane number are fed into fuel inlet hole of engine with some consistent values of consumption. Average intensity of detonation is computed per each consumption and consumption that produces maximum intensity of detonation is computed from resultant of series of average intensities of detonations by method of curve plotting. EFFECT: enhanced authenticity of measurements, decreased amount of fuel needed to determine octane number. 4 cl, 6 dwg
