| 摘要 |
PROBLEM TO BE SOLVED: To provide a control method of a gas engine using a mixed fuel gas capable of operating the engine at an appropriate excess air ratio and air-fuel ratio in accordance with a change in a mixture ratio of the fuel gases. SOLUTION: The gas engine uses a mixed fuel gas including a first fuel gas and a second fuel gas that has less theoretical air amount than that of the first fuel gas. The gas engine includes an air-fuel ratio control valve, a lean burn sensor, and a control device. A memory portion of the control device stores an appropriate reference air-fuel ratio map when using a mixed fuel with zero mixture ratio of the second fuel gas, and an appropriate maximum air-fuel ratio map when using a mixed fuel with the maximum mixture ratio of the second fuel gas. From the excess air ratio acquired by an output of the lean burn sensor and an opening of the air-fuel ratio control valve, the control device obtains a mixture ratio of the second fuel gas among the mixture gas during operation based on both the existing air-fuel ratio maps, and then creates an appropriate air-fuel ratio map corresponding to the acquired mixture ratio to drive the engine. COPYRIGHT: (C)2008,JPO&INPIT
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