摘要 |
Two embodiments of induction systems for internal combustion engines having, in addition to the normal main induction passages, smaller cross-sectional area sub induction passages. The intake charge during idle and low load conditions is delivered to the engine cylinders through the sub induction passage to promote turbulence and improve combustion efficiency under these running conditions. The high load requirements of the engine are supplied through the main induction passage so as to improve volumetric efficiency and reduce pumping losses. Throttle valves control the proportion of the flow through the respective induction passages. In accordance with one embodiment of the invention, the throttle valve which controls the flow through the sub induction passage is positioned as close as possible to the chambers so as to improve intake efficiency. In another embodiment of the invention, at least one of the flow control throttle valves is positioned in a separate housing which has an extremely smooth bore to minimize leakage and to offer lower manufacturing costs.
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