| 摘要 |
PURPOSE:To enable to attain optimum mixture-ratio control according to the temperature of an engine comprising multiple fixed-venturi carburetors in which a variable throttle valve is disposed in a common intake passage on the upstream side of said carburetors, by controlling the opening of the variable throttle valve according to the engine temperature. CONSTITUTION:When the engine temperature is low at the time of starting an engine, a piston 33 of an atmospheric-air by-pass means 31 is kept a large distance away from a seat 35 by the function of a temperature-sensitive means 32, so that the atmospheric air is introduced into a negative-pressure chamber 22 of a control valve 6 via an atmospheric-air control port 38, the seat 35 and a conduit 45. Resultantly, a diaphragm 24 is moved downward by the force of a spring 23 and a variable throttle valve 5 is turned to a position (a) by a rod 21 and a lever 27, so that the quantity of air supplied to carburetors 7-10 via an intake passage 4 is reduced. On the other hand, when the distance between the piston 33 and the seat 35 becomes small as warming-up of the engine proceeds, the negative pressure introduced from a vacuum port 16 into the negative-pressure chamber 22 via a conduit 26 is raised, so that the variable throttle valve 5 is turned toward a position (b). |
