Intake port pressure control system and engine control method

PURPOSE: To provide a device for controlling the pressure in a trapped volume in order to increase the engine performance particularly in the idling in the engine which comprises a check valve in an intake passage to a cylinder of the engine, and having the trapped volume defined between an intake valve and the check valve. CONSTITUTION: In an intake port pressure control device, a by-pass port 38 is opened in an intake passage, and communicated with a trapped volume 36 defined by the portion of the intake passage between the check valve 34 and the intake valve 26. Further it comprises a control valve 54 comprising the outlet passages 55, 58, the secondary passages 56, 59, and an actuator 57 for communicating these passages. The actuator adjusts the flow area between a secondary passage and the outlet passage on the basis of the operating condition of the engine. The outlet passage is connected to a by-pass port, and the secondary passage is connected to a secondary air source 46. The control valve enables a controlled air flow from the secondary air source to the trapped volume when the intake valve is closed. COPYRIGHT: (C)1992,JPO