PURPOSE: To improve the responsiveness at the time of sudden opening of a throttle valve by bringing the nozzle opening to the nearly narrowest condition at the time of the low revolution and low load of an engine.
CONSTITUTION: A variable nozzle 3 is fully closed by keeping a control valve 18a closed when an engine 1 is in a low load or low revolution condition. If a throttle valve 11 is opened so as to accelerate the engine from this condition, since the variable nozzle 3 is kept closed, the flow velocity of exhaust gases increases rapidly. if the engine exceeds a prescribed operating region, by opening the control valve 18a to introduce a supercharged pressure into an actuator 20, the opening of the variable nozzle 3 is increased to avoid an excessive supercharging.
KUBOTA OSAMU
KISHI NORIYUKI
KATO ATSUSHI
