| 摘要 |
<p>PURPOSE:To improve responsiveness of an exhaust by-pass valve at the time of deceleration and low-speed operation of an engine, by controlling an exhaust by- pass valve disposed in an exhaust by-pass passage by-passing a turbine of a turbocharger according to the supercharging pressure and the negative intake pressure. CONSTITUTION:When the negative pressure produced at a port 51 of a throttle valve 50 is intoduced into a signal chamber 36 of a control valve 30 at the time of deceleration or low-speed operation of an engine, a diaphragm piston 35 is moved to the right and an open end of a pipe member 36b is detached from a valve 37. Resultantly, the negative pressure is supplied to a second signal chamber 25 of an actuator 20 via a pipe passage 36a and an output pressure port 33 and a diaphragm 23 is moved to the left, so that an exhaust by-pass valve 17 is opened by a rod 22, etc. On the other hand, when the throttle valve 50 is opened greatly and positive pressure is developed at the port 51 at the time of medium- or high-speed operation of the engine, the by-pass valve 17 is closed by the positive pressure introduced into the signal chamber 36, and the diaphragm 23 is displaced in response to the supercharging pressure introduced into a first signal chamber 24.</p> |
