Internal combustion engine equipped with a turbocharger

摘要

An internal combustion engine comprising an intake duct and a turbocharger arranged in the intake duct. A primary throttle valve connected to the accelerator pedal is arranged in the intake duct located downstream of the turbocharger. A secondary throttle valve is arranged in the intake duct located downstream of the primary throttle valve. An auxiliary intake passage is branched off from the intake duct located between the primary and the secondary throttle valves and is connected to the intake passage located downstream of the secondary throttle valve. The secondary throttle valve is gradually closed from the full open position as the level of the vacuum or the positive pressure, which are produced in the intake duct located between the primary and the secondary throttle valves, is increased.