INTAKE AIR NEGATIVE PRESSURE TAKE-OUT MECHANISM OF AIR-FUEL RATIO CONTROL DEVICE FOR GAS VALVE TYPE LARGE GAS ENGINE

摘要

PURPOSE:To always enable a proper intake air negative pressure to be taken out, and to enhance operability by providing a rotary type open/close valve between the intake air negative pressure take-out port on the downstream side of an intake air throttle valve and a regulator, so that the turning position of covers being externally fitted on the valve shaft can be regulated. CONSTITUTION:A regulator which controls the pressure of fuel gas regulates the gas pressure by means of the intake air negative pressure introduced by an intake air negative pressure lead pipe 19 or the like and the elastic force of a build-in spring. In this case, on the way of the intake air negative pressure lead pipe 19, a rotary open/close valve 37 having a valve shaft 43 which is rotated at the half speed of the crankshaft is provided. In the respective ends of the valve shaft 43, a first and a second grooves 63, 64 are formed, and both grooves 63, 64 are communicated with the intake air pipe on the downstream side of a throttle valve via a negative pressure passage 60 in the shaft center of the valve shaft 43, and a negative pressure lead pipe 14. And a first and a second bottomed cylindrical covers 51, 52 are rotatably fitted on the valve shaft 43, and by regulating the turning positions of these covers, the communicating conditions of respective outlet ports 65, 66 to the respective grooves 63, 64 are controlled.