| 摘要 |
PURPOSE:To permit proper amount of EGR corresponding to driving by controlling the negative pressure in an intake pipe which controls the EGR control valve for internal combustion engine by means of the variable throttle which is controlled by the intake pressure and torque. CONSTITUTION:The intake and exhaust pipes 8 and 2 of an engine 1 are allowed to communicate to the EGR passages 3 and 5 having an EGR control valve 4 and an EGR valve 6 interposed. The EGR valve 6 is interlinked with a throttle valve 7, and the control valve 4 is opened and closed by the intake negative pressure which is transmitted to a diaphragm chamber 15 through a port 27 which opens to an intake pipe 8. In a negative pressure passage 30, a vacuum modulator 10 is arranged which controls the negative pressure amount according to the difference of pressure before and behind the EGR valve 6. Further, in the vicinity of the port 27, a variable throttle 17 driven by a step motor 20 is arranged, and the motor 20 is controlled by the computer 25 which receives the signals from a pressure-voltage transducer 19 and a torque sensor 23. |
