US Patent 12122229 Fault-tolerant fuel isolation from engine firebay

Fuel isolation systems, apparatuses and methods are described. In some embodiments, a system comprises a connector coupled inline with a fuel line on a cold side of the fuel line, a valve coupled to the connector, a fluid feed line coupled to a fluid source and to the valve. In the event of an engine fire condition, a control unit outputs signaling to stop pumping the fuel and to operate the valve to introduce fluid from the fluid source into the fuel line. The introduced fluid provides a siphon break in the fuel line such that the only fuel that can pass the firewall is the remaining fuel in the fuel line downstream of the connector and the introduced fluid.