| 摘要 |
PURPOSE:To make air-fuel ratio per a cylinder, controllable by obtaining an output value of specific wavelength during the specific time from the ignition timing to the time, in which a peak value is shown by a combustion pressure, and the air-fuel ratio from this output value, in the case of obtaining the air-fuel ratio by detecting combustion light of an internal combustion engine. CONSTITUTION:Combustion light in a combustion chamber of an engine is drawn out by a light detecting part 1 and input to each optical filter 30, 31 in a signal processing circuit. In the optical filter 30, for instance, only light of wavelength for showing a CH radical component is transmitted, while in the filter 31, for instance, only light of wavelength for showing a C2 radical component is transmitted, and the light from each filter 30, 31 is input to peak hold circuits 34 to 36 via photoelectric converting elements 32, 33. By holding a peak value A in the first time by each of circuits 34, 35 and holding an offset value D in a predetermined period by the circuit 36, these values A, D are subtracted by subtracters 37, 38 with only the radical components extracted, and air-fuel ratio is obtained based on radical ratio R obtained by dividing both radical components through a divider 39. |
