Patent ID: 11898504
Assignee: BJ ENERGY SOLUTIONS, LLC
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F  E  Y | IPC E  F

Claim 10:
11. A method of operating a dual fuel engine positioned to operate on a liquid fuel and a gaseous fuel, the method comprising:
supplying a first fuel to a combustion chamber of the dual fuel engine through a manifold and a first fuel circuit when no fuel is supplied to the manifold through a second fuel circuit such that the dual fuel engine is in a first mode of operation;
switching the dual fuel engine to a second mode of operation such that a second fuel is supplied to the combustion chamber through the manifold and the second fuel circuit when no fuel is supplied to the manifold through the first fuel circuit;
supplying combustion air to the combustion chamber with a primary compressor of the dual fuel engine;
diverting purge air from the primary compressor into a common purge line including 1) one or more backflow prevention valves configured to prevent backflow within the common purge line, and 2) a pneumatic intensifier configured to increase the purge pressure of the purge air from the primary compressor of the dual fuel engine through a purge inlet during operation of the dual fuel engine, the purge air being separated from the combustion air before the combustion chamber;
positioning a directional control valve in a first position when the dual fuel engine is in the first mode of operation such that the purge air flows into the manifold via the second fuel circuit at a purge pressure equal to or greater than a pressure within the combustion chamber such that backflow from the combustion chamber into the second fuel circuit is prevented; and
positioning the directional control valve in a second position when the dual fuel engine is in the second mode of operation such that the purge air flows into the manifold via the first fuel circuit at a purge pressure equal to or greater than a pressure within the combustion chamber such that backflow from the combustion chamber into the first fuel circuit is prevented;
wherein the one or more backflow prevention valves are upstream of the pneumatic intensifier; and
wherein the common purge line includes a pressure sensor configured to provide a signal indicative of a pressure of the common purge line, and the dual fuel engine further comprising a control system configured to receive the signal from the pressure sensor and control a position of the purge inlet in response to the signal from the pressure sensor.