| 摘要 |
PURPOSE:To recirculate exhaust gas at proper rate by using a computer to control the opening of an exhaust recirculation control valve, to which a required pressure and an actual pressure in the down stream of an orifice. CONSTITUTION:A pressure sensor 26 is put between an exhaust recirculation control valve 24 and an orifice 25 which are provided in an exhaust reicrculation pipe 23. The censor is donnected to a computer 27. Applying those outputs of an engine cooling water sensor 32, an engine speed sensor 33, a transmission neutral switch 34, a transmission top switch 35, an air flow meter 30, and a throttle valve switch 29, the computer 27 determine a required pressure in the down stream of the orifice 25, at which exhaust gas can be recirculated at a proper rate according to the operational state of an internal combustion engine 20. Depending on the difference between the result and an actual pressure in the down stream of the orifice 25 sent from the pressure sensor 26, a solenoid valve 39 is opened or closed so that a signal negative pressure supplied from a suction passage 22 into a negative pressure operation room 37 is affected by atmospheric pressure. The opening of the exhaust recirculation control valve 24 is controlled and provides the proper rate of exhaust recirculation according to the operational state of the engine. |
