| 摘要 |
PURPOSE:To accurately perform exhaust gas recirculation (EGR) control with simple constitution, by changing setting pressure in accordance with a lever opening of a fuel injection pump through a constant pressure valve, additionally imparting a function, which enables to change the setting pressure also by hydraulic pressure, to the constant pressure valve and controlling an EGR valve through pressure from the constant pressure valve. CONSTITUTION:An exhaust gas recirculation (EGR) valve 2 set in an EGR passage 1 is constituted to be controlled opening and closing by supplying negative adjusted from a constant pressure valve 45 to a pressure chamber 25 of the valve 2 through an opening 26. The valve 45 is further provided to a fuel injection pump 4 and can change tension of a built-in spring through a screw shaft 40 in accordance with turning operation of a fuel control lever 411 of the pump 4. While oil pressure of a timer piston 42 is applied to the top end boss part of a spool valve body housed in the pump 45. Then the spool valve body is constituted such that the body is moved to balance tension of said spring and hydraulic pressure acting on the boss part, and negative pressure regulated in accordance with the position of the body is supplied to the chamber 25 from a negative pressure pump 5. |
