To suppress the effects of fuel gas components on a gas consumption apparatus, by monitoring a component ratio of the fuel gas supplied, from supply equipment connected to a gas conduit.
A cutoff valve 12 is disposed to a connecting pipe 5 for connecting the fuel gas supply equipment 1b to the gas conduit 3, and a component-monitoring device 11 is provided for monitoring the fuel gas components of the fuel gas passing through the connecting pipe 3. The gas conduit 3 is connected to a gas engine 4, and a total control device 22 is connected to the component monitoring device 11, calculates a knocking index of an evaluation value, at which the knocking occurs in the gas engine from the fuel gas component ratio detected by the component monitoring device 11, and closes the cutoff valve 12, when the knocking index is compared with a specified threshold for cutoff and the knocking index lies within a range in which the knocking of the gas engine 4 is increased.
MATSUMURA SHOJIRO
FUJIWAKA TAKAO
