Fuel/air mixture supply system with additional air supply
 Disclosed is a fuel/air mixture supply system for an internal combustion engine of the single-point fuel injection type wherein, the intake manifold system is formed with a first fuel/air supply passage which inspires atmospheric air and which has fitted generally at a midpoint thereof a fuel injection valve which injects fuel into the inspired air. The fuel/air mixture then proceeds to a first set of branched passages, each one of which conducts the fuel/air mixture to a cylinder of the engine. Further, there is provided a second air supply passage which inspires atmospheric air and which branches into a second set of branched passages, each one of which conducts air to a cylinder of the engine. The first fuel/air supply passage is smaller than the second air supply passage, and the first set of branched passages are smaller than the second set of branched passages. The flow of air/fuel mixture in the first fuel/air supply passage is controlled by a first throttle valve, and the flow of air in the second air supply passage and/or the second branched passages is controlled by a regulating means responsive to the operation of the first throttle valve, so as to be substantially zero when the first throttle valve is open an amount less than a certain predetermined amount, while, when the first throttle valve is opened greater than the certain predetermined amount, the flow is progressively increased. 
Nissan Motor Company, Limited
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inventional inventional inventional inventional inventional
Yoshihisa Yuko Masaaki Mitsumasa
Kawamura Sugo Saito Inoue