| 摘要 |
PURPOSE:To function a negative pressure actuator even under malfunction of vacuum pump thus to achieve failsafe by leading the intake negative pressure to be produced in the downstream of intake throttle valve upon dropping of the negative pressure of vacuum pump below predetermined level to the actuator. CONSTITUTION:Upon droppage of the negative pressure at the intake port 25 of vacuum pump 24 below predetermined level, a pressure switch 39 will turn on to open a solenoid valve 38. While upon breaking of belt 23 or malfunction of the vacuum pump 24, the pressure switch 39 will turn on to open the solenoid valve 38 to communicate between the intake path 34 in the downstream of intake throttle valve 30 and the branch tube 37 coupled to the vacuum multiplier device 28. Since no negative pressure is fed to the negative pressure chamber 31a, downward force is applied through a spring 36 onto the diaphragm 32 to extend the rod 33 thus to open the intake throttle valve 30 thereby negative pressure is produced in the intake path 34 and fed to said device 28. |
