Fuel recirculation method and valve
Fuel recirculation methods, fuel supply circuits and fuel recirculation valves for selectively mixing hot return fuel from a diesel engine with fuel from a tank before providing it to back to the engine. In exemplary disclosed embodiments of fuel recirculation valves, the valves are configured to selectively mix the fuel in a controlled manner using a temperature sensitive actuator within the valve such that, when the temperature of the fuel reaches a certain point, the valve restricts flow pathways to reduce heated fuel being mixed with fuel from the fuel tank, and eventually closes to prevent any heated fuel from being mixed and overheating the fuel provided to a fuel filter, a fuel pump and the engine. Disclosed fuel circulation valves are separate from the fuel filter and are placed upstream of the filter.
1. A fuel recirculation valve for use in a fuel supply circuit that supplies filtered fuel to an engine, comprising:
a body including:
a first inlet configured to receive fuel into the body from a first source;
a second inlet configured to receive fuel into the body from a second source separate from the first source;
a single outlet configured to allow fuel to exit the body and be provided to a filter that is external to the body, wherein the body is configured such that fuel from the first source and the second source can only exit the body through the outlet;
a first passage connecting the first inlet to the outlet, the first passage having a first portion in communication with the first inlet, a second portion in communication with the outlet and a middle portion between the first portion and the second portion, the first passage providing a path for fuel from the first source to travel from the first inlet to the outlet;
a second passage connecting the second inlet to the first passage at a node positioned between the first inlet and the middle portion of the first passage, the second passage providing a path for fuel from the second source to travel from the second inlet to the node so that fuel from the second source is capable of being mixed with the fuel from the first source at the node; and
an actuator located within the first passage, the actuator having an unactuated position and an actuated position, and wherein when the actuator is in the actuated position, fuel from only the first source is received into the body and exits through the outlet, wherein the actuator blocks the second passage to prevent fuel from traveling from the second inlet to the node such that fuel cannot be received into the body from the second source at the second inlet and exit the body through the outlet, and wherein when the actuator is in the unactuated position, fuel from both of the first and the second sources are received into the body and exit through the outlet.
2. The fuel recirculation valve of claim 1 , wherein the actuator includes a temperature sensitive element positioned within the middle portion of the first passage, the temperature sensitive element being capable of being in communication with fuel in the middle portion of the first passage and wherein the temperature sensitive element causes the actuator to move between the unactuated and the actuated position.
3. The fuel recirculation valve of claim 2 , wherein the body has a cavity in which the actuator is seated and wherein in the actuated position, a portion of the actuator extends into the second passage to block flow of fuel from the second inlet to the node.