| 摘要 |
PURPOSE:To improve warming performance of an exhaust system without deteriorating the idle operation property at engine cooling by connecting a fluid pressure operating chamber to a suction delivery port when the rate of warming is less than a prescribed value and also in an idle operation, and otherwise connecting it to the atmosphere. CONSTITUTION:When the cooling water temperature of an internal-combustion engine is lower than a prescribed value, a solenoid valve 27 is turned on at idle operation, and a diaphragm chamber 23 is connected to a suction pipe negative pressure delivery port 29, allowing a valve element 17 to be fully closed. In other operating state except the case described above, power supply to the solenoid valve 27 is stopped, and the atmospheric pressure is fed into the diaphragm chamber 23, allowing the valve element 17 to be fully opened. With the engine cooling water temperature over the prescribed value, the solenoid valve 27 is always turned on, allowing the pressure appearing at the negative pressure delivery port 29 in the suction pipe to be introduced into the diaphragm chamber 23. At the idle operation and a low load operation, negative pressure over the prescribed value is fed into the diaphragm chamber 23. |
