PURPOSE: To prevent the excessive supply of the concentrated mixed gas by installing a valve into an air intake passage for introducing the atmosphere into a negative pressure chamber formed on the back surface of the piston of the captioned carburetor and opening said valve when the environmental temperature is below a prescribed value and closing said valve after the lapse of a prescribed time.
CONSTITUTION: A venturi part 2 on the upstream side of a throttle valve 1 is constituted of a fixed wall 3 and a piston 4, and the effective passage area of the venturi part 2 can be varied by advancing and retreating the piston 4 by the negative pressure introduced into a negative pressure chamber 8 formed on the back surface of the piston 4 from a negative pressure passage 7. In this case, an intake passage 13 for introducing the atmosphere into the negative pressure passage 8 is formed, and one edge is connected to an intake passage 12 on the upstream side of the venturi part 2. A solenoid valve 14 is installed into the intake passage 13, and said valve 14 is opened when the cooling water temperature is below a prescribed value by an electric control circuit 16 according to the output of a temperature sensor 15 for detecting the engine cooling water temperature, and closed after the lapse of a prescribed time.
NISHIO SHIGERU
NAKAMURA KAN
NONOYAMA TAKAO
TOYOTA MOTOR CORP
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