Abstract: A fuel refilling system may comprise a fueling station, a fuel tank, and a recirculation module in selective fluid communication with one another. The fuel refilling system may comprise a control module configured to generate one or more signals for controlling flow rates of the fuel into and out of the fuel tank, so as to remove and direct a first portion of heated fuel from the fuel tank to the recirculation module, and replace the first portion of heated fuel that is removed from the fuel tank with incoming cooler fuel received from the fueling station and/or the recirculation module. Convective mixing of the cooled fuel with the remaining heated fuel in the fuel tank may cause a temperature of the fuel mixture in the fuel tank to reduce. Accordingly, a filling capacity of the fuel tank may be increased as a result of the temperature reduction in the fuel mixture in the fuel tank.

Abstract: Improved methods, systems, and devices for filling fuel tanks, particularly compressed natural gas (CNG) fuel tanks, are provided. Such methods, systems, and devices enhance heat rejection when the fuel tank is being filled to a temperature lower than that if such methods, systems, and devices were not used. Pressure sensor logic on a fuel station will be less prone to error in gauging the mass of the fuel in the tank, enabling the tank to be filled more accurately and fully. To enhance heat rejection, the fuel tank may be provided with a heat sink to passively facilitate heat transfer from the fuel tank interior to the exterior. Alternatively or in combination, the fuel tank can be provided with a fuel flow channel through which fuel from the fuel tank interior is circulated. The fuel flow channel can be actively cooled with a fan or water cooling system.

Abstract: Improved methods, systems, and devices for filling fuel tanks, particularly compressed natural gas (CNG) fuel tanks, are provided. Such methods, systems, and devices lower the heat of compression when the fuel tank is being filled to a temperature lower than that if such methods, systems, and devices were not used. Pressure sensor logic on a fuel station will be less prone to error, enabling the tank to be filled more accurately and fully. To lower heat of compression, an insert is placed within the tank. The insert changes the flow characteristics of the fuel that is being delivered into the tank. Typically, the delivered fuel will be released into the interior of the tank in a vortex fashion to fill the tank. Other flow modification devices are also provided including an externally coupled Ranque-Hilsh vortex tube and a flow modification chamber built within a fuel tank.