AIR INTAKE DEVICE FOR MULTICYLINDER ENGINE

摘要

PURPOSE:To increase the output of an engine over the whole operational range of an engine by providing a primary throttle valve closely upstream from the air intake port of each cylinder and making a volume chamber located upstream therefrom communicate with the primary throttle valve through air intake passes for a high speed provided with secondary throttle valves and normally opened air intake passes for a low speed and setting the lengths of exhaust passes to a medium speed range. CONSTITUTION:A primary throttle valve 14 is provided closely upstream from the air intake port 6 of each cylinder 5. An air intake pass up to a volume chamber 12 located upstream from the primary throttle valve 14 comprises an air intake pass 6b for a high speed provided with a secondary throttle valve 16 and a normally open suction pass 6a for a low speed without any valve. In a low engine speed, the secondary throttle valve 16 is fully opened to obtain an inertia intake air corresponding to the low engine speed. In a high engine speed, the secondary throttle valve 16 is opened to obtain an inertia intake air corresponding to the high engine speed. The length of the exhaust system of the engine is set such that most of air intake is performed when air intake and exhaust valves overlap each other due to the inertia effect utilizing an exhaust pulsation in a medium engine speed.