| 摘要 |
PURPOSE:To obtain optimum air-fuel ratio in each state of an engine, starting, perfect combustion and warm-up, by controlling air-fuel ratio in accordance with temperature of the engine at its starting operation and controlling feed quantity of a mixture through a separate mixture control part at starting and warm-up operation with perfect combustion as a border. CONSTITUTION:When an engine 1 is started, air is fed to a starting mixture supply part 26 in a carburetor 5 from a subair cleaner 7 via a pipe 11 by cranking negative pressure, and a mixture is sucked from a starting nozzle 30. This mixture passes through a pipe 10 to reach a control unit 3, after metering in the first mixture control part 42 of a valve 37, the mixture is fed to an intake pipe 6 via the pipe 11. If suction negative pressure is increased by perfect combustion of the engine, a valve 44 is moved leftward by negative pressure in a negative pressure chamber 32 through a diaphragm 49 to close a passage 53 and throttle flow quantity of the mixture. Thereafter, in progress of warm-up operation, the valves 37, 55 are operated rightward through bimetals 38, 56, and the mixture is throttled by the first and second mixture control units 42, 43 and fed to the intake pipe 6. |
