| 摘要 |
A method and a system for controlling a gas engine system, capable of performing highly accurate air-fuel ratio control even for a low calorie fuel gas having a calorific value which tends to easily fluctuate. In the method, air supplied through a supercharger and fuel gas passing through a fuel gas supply pipe and subjected to control by a fuel control valve which controls the amount of supply of the fuel gas are mixed to produce a mixed gas, and the mixed gas is supplied into a combustion chamber. When the fuel gas is a low calorie gas or when an engine output is high, a part of the fuel gas is diverted at that point of the fuel gas supply pipe which is upstream of the fuel flow control valve, and the flow rate of the diverted fuel gas is set to be a specified flow rate less than the flow rate of the fuel gas which is not diverted. Then, the diverted fuel gas is supplied into the combustion chamber through a branch control valve installed in a gas supply branch pipe, the remaining fuel gas is supplied to the fuel flow control valve via a gas supply main pipe, and the amount of fuel gas is controlled so that the mixed gas supplied into the combustion chamber has a predetermined air-fuel ratio. On the other hand, when the fuel gas has high calorie or when the engine output is low, the branch control valve is closed to supply the fuel gas to only the gas supply main pipe. |
