| 摘要 |
PURPOSE:To prevent the shortage of air passed through a mixing passage, by opening an air-flow rate correcting valve to its full opening at the time of low load operation of an engine. CONSTITUTION:When an engine is operated under the load condition from high load to low load, a throttle valve 32 is opened to a relatively large angle, so that a large amount of air is passed through a mixing passage 28. Therefore, a large amount of fuel is drawn from a fuel gas source and air-fuel mixture of a proper concentration is supplied into a crank chamber 8. On the other hand, at the time of low-load operation or no-load operation of the engine when the throttle valve 32 is a little closed, the quantity of air passage through the mixer 28 and the quantity of fuel drawn from the fuel source is reduced at a greater rate, so that the concentration of air-fuel mixture tends to become leaner than a proper value. In this state, however, a valve 35 for controlling the flow rate of air through an air passage 29 is opened to an angle greater than the throttle valve 32 to increase the flow rate of air through the air passage 29 and to thereby draw out fuel sufficiently. Therefore, it is enabled to prevent lowering of the concentration of air-fuel mixture. |
