US 11,946,420 B1
Fuel systems having thermal recirculation
Edward W. Goy, Crystal Lake, IL (US); Ryan Prescott Susca, Windsor, CT (US); and Ryan Shook, Loves Park, IL (US)
Assigned to Hamilton Sundstrand Corporation, Charlotte, NC (US)
Filed by Hamilton Sundstrand Corporation, Charlotte, NC (US)
Filed on Jun. 22, 2023, as Appl. No. 18/213,053.
Int. Cl. F02C 7/236 (2006.01); F02C 7/14 (2006.01); F02C 7/22 (2006.01); F02C 7/232 (2006.01); F02C 9/32 (2006.01)
CPC F02C 7/236 (2013.01) [F02C 7/14 (2013.01); F02C 7/222 (2013.01); F02C 7/232 (2013.01); F02C 9/32 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A fuel system, comprising:
a main pump assembly having:
a main fuel pump connected to an input line and configured to pump fuel to a main fuel control via a main fuel control line;
a recirculation pump connected to the input line;
a fuel recirculation system connected to an outlet line of the recirculation pump and upstream of the main fuel control, the fuel recirculation system configured to select a mode from a plurality of modes, wherein the plurality of modes include a recirculation mode and a backup mode, wherein the fuel recirculation system is configured to recirculate fuel from the recirculation pump to a tank through one or more coolers in the recirculation mode, and provide fuel to the main fuel control in the backup mode; and
a recirculation control configured to select between the recirculation mode and the backup mode, wherein the recirculation control includes:
a first selector valve in fluid communication with the outlet line of the recirculation pump, with a recirculation return line connected to return fuel to the input line, and with an inter-valve line, wherein the first selector valve is configured to select between connecting the outlet line of the recirculation pump with either the recirculation return line or with the inter-valve line; and
a second selector valve in fluid communication with the inter-valve line, with a back-up line connecting the second selector valve to the main fuel control, and with a cooler recirculation line connected to supply the one or more coolers, wherein the second selector valve is configured to select between connecting the inter-valve line with either the back-up line or with the cooler recirculation line.