Lane, Aitken, Kice & Kananen
Coarse and fine air supply control for closed-loop controlled carbureted internal combustion engines
 In a closed loop air-fuel mixture control system for carburetor-equipped internal combustion engines, an exhaust gas sensor provides a feedback signal to a control unit where the signal is modified to meet the control characteristics of the closed loop. The modified feedback signal is converted into digital pulses whose width varies with the amplitude of the feedback signal. Additional air is supplied to the engine through an air bleed in accordance with the magnitude of the analog feedback signal to provide a coarse control of air-fuel ratio and in response to the digital pulses to provide a fine control of the ratio. The mixture is controlled in a wide range of ratios to eliminate the need for calibration which would be required for fitting the closed loop system to the time-varying characteristics of individual carburetors. 
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F02M F02D
inventional inventional
Hiroshi Kenji Michiyoshi Akio Masaaki
Sanbuichi Ikeura Yamane Isobe Saito