| 摘要 |
PURPOSE:To obtain EGR in accordance with the change of exhaust pressure by providing an air-introduction valve to introduced the air into a diaphragm chamber of an exhaust gas return control valve in accordance with the pressure difference on both sides of a particulate trapper of an exhaust pipe between a negative pressure control valve and an exhaust gas return amount control valve. CONSTITUTION:An air-introduction valve 17 is provided between passages 11 and 12 connecting an EGR valve 1 to a negative pressure control valve 10. A particulate trapper 16 is equipped between exhaust pipes 14 and 15. When it is choked with particulate, the exhaust pressure in the exhaust pipe 14 is raised, and the exhaust pressure and the pressure difference in another exhaust pipe 15 is increased. Thereby, a valve body 19 is shifted to the left against the elastic force of a spring 22, an air passage 18 is opened, the air is introduced into a diaphragm chamber 13 of the EGR valve 1, and a valve body 6 is moved to the left. Consequently, the amount of EGR is to be reduced. |
