A diesel fuel recirculation device may include a fuel tank configured to store and supply diesel fuel, a main filter connected to the fuel tank and filter diesel fuel to supply the filtered diesel fuel to an engine, and a recirculation member provided in the main filter and be resupplied with high temperature fuel from the engine to supply the resupplied high temperature fuel to the fuel tank or the main filter, such that marketability and usage convenience may be improved by increasing a temperature of the fuel using the high temperature fuel resupplied from the engine to shorten a starting time under low temperature conditions.

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.

A method of improving fuel efficiency in a diesel fuel internal combustion engine on a vehicle includes providing a combustion system including a fuel tank, an engine, and a fuel line disposed between the fuel tank and the engine. A heat exchanger is positioned on the fuel line between the fuel tank and the engine. Working thermal fluid is passed from a reservoir through the heat exchanger while fuel is passed through the heat exchanger, increasing the temperature of the fuel passing through the heat exchanger. A vibration isolation mount is installed between the heat exchanger and the vehicle, thereby reducing vibration of the heat exchanger during use of the vehicle. Heated fuel from the heat exchanger is delivered to the engine, improving the fuel efficiency of the engine by burning the heated fuel.

A fuel heating apparatus including a heat exchanger body having a first removable end plate, a main body, and a second removable end plate opposite the first removable end plate. The first and second removable end plates are secured to opposing sides of the heat exchanger main body by a plurality of threaded fasteners. The first removable end plate includes a fuel inlet line and a thermal fluid inlet line, and the second removable end plate includes a fuel outlet line and a thermal fluid outlet line. The main body includes a plurality of interior first fluid pathways and a plurality of interior thermal fluid pathways defined therein, the interior first fluid pathways being responsible for connecting the fuel inlet line to the fuel outlet line and the interior thermal fluid pathways being responsible for connecting the thermal fluid inlet line to the thermal fluid outlet line.

A recirculation module for a fuel prefilter unit of a combustion engine has a temperature-controlled actuating element that transfers the recirculation module, based on a filter raw side feed temperature of the fuel, from a cold start state into a normal operating state and back. In cold start state, an engine return line from the combustion engine to the recirculation module is in fluid communication with a filter element raw side of the fuel prefilter unit and the engine return line is separated in regard to fluid communication from a tank return line of the combustion engine. In normal operating state, the engine return line is separated in regard to fluid communication from the filter element raw side and is in fluid communication with the tank return line. A check valve prevents return flow of fuel from the tank return line into the engine return line.

A delivery device for the fuel of an internal combustion engine has a fuel tank (4) from which at least one fuel pump (14, 18) delivers fuel via a fuel supply line (10) and via at least one fuel filter (12, 16) to a fuel consumer (2). The consumer (2) is connected to the fuel tank (4) via a fuel return line (20). A control device (24) is connected between the supply line (10) and the return line (20). The control device establishes a fuel-conveying connection (80) between the return line (20) and the supply line (10) when the temperature in the fuel tank (4) falls below a predeterminable threshold temperature and at a predeterminable threshold pressure in the return line (20).

A valve device for a fuel filter module has a first fluid channel through which fuel flows only in recirculation mode of the fuel filter module and a second fluid channel through which fuel flows only outside of the recirculation mode. The first fluid channel extends inside the second fluid channel. The first and second fluid channels are coaxial to each other. A fuel filter module switchable into recirculation mode and out of recirculation mode is provided with a control valve that has a valve bore and a valve device arranged in the valve bore, wherein the valve device has a first fluid channel through which fuel flows only in recirculation mode and a second fluid channel through which fuel flows only outside of the recirculation mode. The first fluid channel extends inside the second fluid channel, and the first and second fluid channels are coaxial to each other.

A delivery device for the fuel of an internal combustion engine, having a fuel tank (4), from which at least one fuel pump (14, 18) delivers fuel via a fuel supply line (10) and at least one fuel filter (12, 16) to a fuel consumer (2), which is connected to the fuel tank (4) via a fuel return line (20), is characterized in that a control device (24) is connected between the supply line (10) and the return line (20), which control device establishes a fuel-conveying connection (80) between the return line (20) and the supply line (10) when the temperature in the fuel tank (4) falls below a predeterminable threshold temperature and at a predeterminable threshold pressure in the return line (20).

A recirculation module for a fuel prefilter unit of a combustion engine has a temperature-controlled actuating element that transfers the recirculation module, based on a filter raw side feed temperature of the fuel, from a cold start state into a normal operating state and back. In cold start state, an engine return line from the combustion engine to the recirculation module is in fluid communication with a filter element raw side of the fuel prefilter unit and the engine return line is separated in regard to fluid communication from a tank return line of the combustion engine. In normal operating state, the engine return line is separated in regard to fluid communication from the filter element raw side and is in fluid communication with the tank return line. A check valve prevents return flow of fuel from the tank return line into the engine return line.

A housing has an inner passage to communicate with both a fuel passage, which is to conduct fuel from a fuel pump, and a return passage, which is to return fuel a fuel tank. A valve body is movable in the housing to change a minimum flow passage cross-sectional area of the inner passage. A spring is connected to the valve body and changes its biasing load in correspondence with a fuel temperature to move the valve body. The spring moves the valve body such that the minimum flow passage cross-sectional area, when the fuel temperature is equal to or higher than a predetermined vapor generation temperature, is larger than the minimum flow passage cross-sectional area when the fuel temperature is lower than the vapor generation temperature.