Intake system for an internal combustion engine with at least two cylinders

摘要

An internal combustion engine has throttle valves installed, each of its air intake passages connecting a surge tank with each of the cylinders. An inter-cylindrical connecting passage is formed near the air intake valves between adjacent air intake passages. An auxiliary air intake passage branches from the surge tank to bypass the throttle valve and connects to the inter-cylindrical connecting passage. An idle speed control valve is installed in the auxiliary air intake passage. Thus, stabilized combustion of the air/fuel mixture even during the low to mid-load operating ranges can be obtained to improve fuel economy and reduce NOX emissions. The invention is of particular advantage in engines using exhaust gas recirculation.