Systems and methods utilizing turbine compressor discharge for hydrostatic manifold purge

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.

A manifold pressurization system comprising:

• a purge inlet configured to receive purge air from a compressor of a dual fuel engine positioned to operate on a liquid fuel and a gaseous fuel;
• a common purge line connected at an upstream end to the purge inlet, the common purge line configured to provide the purge air at a purge pressure and 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, wherein a position of the purge inlet has a closed position in which the purge air is prevented from entering the common purge line and an open position in which the purge air is allowed to enter the common purge line;
• a first purge line connected at a downstream end thereof to a manifold chamber of the dual fuel engine via a first fuel circuit;
• a second purge line connected to at a downstream end thereof to the manifold chamber via a second fuel circuit;
• and
• a control valve connected to a downstream end of the common purge line, an upstream end of the first purge line, and an upstream end of the second purge line, the control valve having a first position in which the control valve connects the common purge line with the second purge line, thereby to prevent backflow from the manifold chamber into the second fuel circuit, and the control valve having a second position in which the control valve connects the common purge line with the first purge line, thereby to prevent backflow from the manifold chamber into the first fuel circuit;
• wherein the one or more backflow prevention valves are upstream of the pneumatic intensifier;
• 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 manifold pressurization system further comprising a control system configured to receive the signal from the pressure sensor and control the position of the purge inlet in response to the signal from the pressure sensor.