A fuel filter

Abstract

The utility model relates to a kind of fuel oil fine filter, comprising: main casing, it is provided with oil inlet and oil outlet;Center tube located in the inside of main casing, its pipe wall is provided with connecting port;Filter core is located in the inside of main casing and surrounds on center tube, filter core is used to filter fuel oil;Several flow cavities for fuel oil flow are located in the inside of main casing, including first flow cavity and second flow cavity, first flow cavity is the cavity formed between the inner wall of main casing and the outer surface of filter core, second flow cavity is the tubular cavity formed by the inner cavity of center tube, first flow cavity is connected with oil inlet, second flow cavity is connected with oil outlet, second flow cavity is communicated with first flow cavity by connecting port and filter core;And heating unit is arranged in the bottom of first flow cavity and is used to heat its internal fuel oil.Compared with prior art, the utility model integrates heating unit, greatly solves the problem that engine cannot be started when cold start.

Description

Technical Field

[0001] This utility model relates to the field of filter technology, and in particular to a fuel fine filter. Background Technology

[0002] With increasingly stringent national emission standards for automobile engines, fuel filters require continuous improvement and upgrades. The primary function of a fuel filter is to filter fuel and remove water from diesel fuel. Filtered fuel significantly reduces the probability of injector failure and extends engine life. During engine operation, fuel is filtered, then passed through a high-pressure pump and injectors before being sprayed into the cylinders. When the fuel temperature drops to its freezing point, wax crystals can form, blocking the fuel supply and affecting normal engine operation. Currently, the fuel filter heater unit is typically located within the coarse fuel filter. However, if wax buildup also forms on the fine fuel filter during a cold start, the engine will fail to start. Therefore, a new fine fuel filter is needed to address this issue.

[0003] Fuel pre-filters are typically mounted on the chassis frame, where the product boundaries are relatively loose, and it's easy to install a heater within the pre-filter, usually a rod-type heater. Fuel fine filters, on the other hand, are located on the engine, where product boundaries are very strict and space is limited, making it impossible to directly apply the heater from the fuel pre-filter to the interior of the fuel fine filter.

[0004] Patent publication number CN208742075U discloses a fuel filter that is easy to fix. This is a spin-on filter structure with a base and filter canister threaded together. A heater is set at the top of the base. If the filter element is covered with wax, the wax cannot melt because the heat is transferred upwards, resulting in poor heating effect. Utility Model Content

[0005] The purpose of this utility model is to overcome the defects of the existing technology and provide a fuel filter that integrates a heating unit, which greatly solves the problem of the engine failing to start when cold. The heating unit is located at the bottom of the filter element and inside the housing, which occupies little space and the heat is transferred from bottom to top, resulting in good heating effect.

[0006] The objective of this utility model can be achieved through the following technical solutions: A fuel filter, comprising: The main housing is provided with an oil inlet and an oil outlet; The central tube located inside the main housing has a connection port on its wall; A filter element located inside the main housing and surrounding the central tube, the filter element being used to filter fuel; A plurality of flow chambers located inside the main housing and used for fuel flow include a first flow chamber and a second flow chamber. The first flow chamber is a cavity formed between the inner wall of the main housing and the outer surface of the filter element. The second flow chamber is a tubular cavity formed by the inner cavity of the central tube. The first flow chamber is connected to the fuel inlet, and the second flow chamber is connected to the fuel outlet. The second flow chamber communicates with the first flow chamber through the connecting port and the filter element. And a heating unit disposed at the bottom of the first flow chamber for heating the fuel inside it.

[0007] Furthermore, the heating unit includes: An annular support located at the bottom of the first flow cavity; A plurality of heating elements are arranged circumferentially along the annular support member; And a connector that is connected to the heating element and extends outside the main housing.

[0008] Furthermore, the connector is used to connect with an external wiring harness connector to achieve a power connection.

[0009] Furthermore, the annular support and the main housing are connected and sealed by a first sealing ring; The annular support is provided with a number of screw mounting holes, and the annular support and the main housing are connected by inserting a number of screws into the screw mounting holes.

[0010] Furthermore, the fuel filter also includes a temperature control unit comprising an electrically connected temperature sensor and controller, the temperature control unit being mounted on the annular support and connected to the heating element and connector.

[0011] Furthermore, the temperature control unit is configured such that when the temperature sensor detects that the fuel temperature at the fuel inlet is lower than a first preset temperature, the controller controls the heating element to heat; and when the temperature sensor detects that the fuel temperature at the fuel inlet is higher than a second preset temperature, the controller controls the heating element to stop heating.

[0012] Furthermore, the first flow cavity includes an annular cavity located on the inner wall of the main housing and the outer wall of the filter element, and a water collection cavity located at the bottom of the main housing and below the filter element, with the heating unit installed at the bottom of the water collection cavity.

[0013] Furthermore, a drain valve is provided at the lowest point of the bottom of the water collection chamber.

[0014] Furthermore, the central tube also includes: A central tube body that is closed at the top and connected to the oil outlet at the bottom, wherein the connection port is located at the top of the tube wall of the central tube body; The central tube cap, located above and connected to the central tube body, has an air hole at its top. And several return oil pipelines located on both sides of the central tube body, the top of which is connected to the air hole.

[0015] Furthermore, the main housing is also provided with an oil return port, and the oil return pipeline is connected to the oil return port.

[0016] Furthermore, the outer wall of the central tube body is provided with a threaded structure arranged along its axial direction. The outer wall of the threaded structure contacts the inner wall of the filter element, forming a buffer cavity for storing the fuel filtered by the filter element. The central tube and the filter element are not an integral structure, but are separately detachable.

[0017] Furthermore, the lower end of the central tube body is sealed to the main housing via a second sealing ring.

[0018] Furthermore, the lower end of the central tube is sealed to the main housing via a third sealing ring.

[0019] Furthermore, a top cover plate is connected to the top of the main housing.

[0020] Furthermore, the main housing and the upper cover are detachably connected by threads.

[0021] Furthermore, a filter element cover is fixedly connected to the top of the filter element, and the filter element cover is detachably connected to the upper cover plate.

[0022] Compared with the prior art, the present invention has the following advantages: (1) This utility model integrates the heating unit directly into the bottom of the first flow chamber, which is the area where cold fuel and free water first accumulate and where the temperature is lowest. The fuel at the bottom is directly heated by the ring-shaped heating plates, and the heat is transferred from bottom to top, so that the fuel in the entire first flow chamber can be affected by the heat. The heat energy utilization efficiency is high, and the paraffin crystals that precipitate at low temperature can be quickly melted, so that there is no local fuel wax that cannot be dissolved. The fuel is preheated before entering the filter element, which avoids the waxy substance clogging the filter element and fundamentally ensures the smooth flow of the filtration channel. This ensures that the engine can continuously provide sufficient and clean fuel even in cold environments, and ensures the normal start-up and operation of the vehicle or equipment.

[0023] (2) The present invention sets the heating unit as a ring support and sets several heating plates along its ring direction, so that the heating unit requires little space and does not excessively occupy the available space inside the main housing, so that it can adapt to the structure of the fuel filter.

[0024] (3) This utility model is equipped with a temperature control unit including a temperature sensor and a controller, and sets thresholds for starting heating at a first preset temperature and stopping heating at a second preset temperature. No manual intervention is required; the system automatically monitors, judges, and executes heating commands, providing a good user experience. Heating is only started at a low temperature when needed and stops once the appropriate temperature is reached, avoiding continuous energy waste. It prevents excessively high fuel temperatures and improves the safety of the entire fuel supply system.

[0025] (4) The heating unit of this utility model is installed through a ring support to form an independent and replaceable module. It is fixed and sealed with screws and a first sealing ring. The multiple sealing design ensures that the entire system is leak-free, safe and reliable. The bottom water collection chamber is equipped with a drain valve, which facilitates the periodic manual discharge of accumulated water and impurities. The filter element, heater and temperature controller are integrated into a main housing, which is compact, space-saving and convenient for vehicle layout.

[0026] (5) The central tube of this utility model integrates multiple functions such as fuel collection, buffering, exhaust, and fuel return after filtration. Air and fuel vapor on the upper part of the filter element can enter the fuel return line through the air hole of the central tube cover, and finally return to the fuel tank through the fuel return port. This built-in exhaust and fuel return system can automatically eliminate the air resistance phenomenon in the fuel filter, ensure a continuous and stable fuel supply to the fuel system, and avoid engine power reduction or stalling due to air mixing in the fuel line. Integrating multiple functions into a central tube component makes the overall structure of the fuel filter very compact, eliminating the need for a complex external exhaust circuit.

[0027] (6) The present invention provides an axial thread on the outer wall of the central tube body, so that it forms a buffer cavity between itself and the inner wall of the filter element. This structure greatly increases the temporary storage space and flow area of ​​fuel, reduces flow resistance, and ensures the stability of fuel supply.

[0028] (7) This utility model sets up a flow chamber with a clearly defined function to achieve multi-stage flow chamber synergy, realizing oil-water separation and efficient filtration. The annular cavity allows fuel to pass evenly through the outer surface of the filter element, achieving preliminary diffusion and pre-filtration; the water collection chamber is located at the bottom, where water and heavy impurities will naturally settle and accumulate due to the heavier weight of water than oil. The inner cavity of the central tube of the second flow chamber collects the clean fuel filtered by the filter element and guides it to the oil outlet.

[0029] (8) The central tube and filter element of this utility model are separate, non-integrated structures. The main housing and the upper cover are detachably connected by threads, and the filter element is connected to the upper cover through a filter element cover. Maintenance is convenient and economical. When the filter element needs to be replaced, simply open the upper cover to remove the old filter element. Users can choose to replace only the relatively inexpensive filter element while retaining the fully functional and more expensive central tube, greatly reducing the long-term operating costs for users. This is a huge advantage compared to traditional integrated filters. Attached Figure Description

[0030] Figure 1 This is a cross-sectional view of the fuel filter shown in Example 1; Figure 2 This is a schematic diagram of the heating unit shown in Example 1 (from top to bottom). Figure 3 This is a schematic diagram of the heating unit shown in Example 1 (from bottom to top). Figure 4 This is a schematic diagram of the heating unit and temperature control unit shown in Example 2; Figure 5 This is a connection diagram of the temperature control unit shown in Example 2; Figure 6 This is a cross-sectional view of the fuel filter shown in Example 4; Figure 7 This is a schematic diagram of the fuel filter shown in Example 4; Figure 8 This is a front view of the fuel filter shown in Example 4; Figure 9 This is a schematic diagram (top view) of the central tube shown in Example 4. Figure 10 This is a schematic diagram of the central tube structure shown in Example 4 (viewed from below); Figure 11 This is a schematic diagram of the top structure of the central tube shown in Example 4; Figure 12 This is a schematic diagram of the main housing and the upper cover plate shown in Example 5.

[0031] Explanation of markings in the diagram: 1-Main casing, 11-Oil inlet, 12-Oil outlet, 13-Oil return port; 2-Central tube, 21-Connection port, 22-Central tube body, 221-Second sealing ring, 23-Central tube cap, 231-Vent hole, 24-Return oil line, 25-Threaded structure, 26-Buffer cavity, 27-Third sealing ring 3-Filter element, 31-Filter element cover; 4-Flow chamber, 41-First flow chamber, 411-Annular cavity, 412-Water collection chamber, 4121-Drain valve, 42-Second flow chamber; 5-Heating unit, 51-Annular support, 511-Screw mounting hole, 52-Heating element, 53-Plug-in component, 54-First sealing ring; 6-Temperature control unit, 61-Temperature sensor, 62-Controller; 7-Top cover plate. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments. In the following embodiments or examples, unless otherwise specified, the functional components or structures are conventional components or structures used in the art to achieve the corresponding functions.

[0033] It should be noted that in the description of this utility model, the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," and "connected," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0035] A fuel filter, comprising: The main housing 1 is provided with an oil inlet 11 and an oil outlet 12; The central tube 2 located inside the main housing 1 has a connection port 21 on its tube wall; A filter element 3 located inside the main housing 1 and surrounding the central tube 2, the filter element 3 being used to filter fuel; A plurality of flow chambers 4 located inside the main housing 1 and used for fuel flow include a first flow chamber 41 and a second flow chamber 42. The first flow chamber 41 is a cavity formed between the inner wall of the main housing 1 and the outer surface of the filter element 3. The second flow chamber 42 is a tubular cavity formed by the inner cavity of the central tube 2. The first flow chamber 41 is connected to the oil inlet 11, and the second flow chamber 42 is connected to the oil outlet 12. The second flow chamber 42 communicates with the first flow chamber 41 through the connecting port 21 and the filter element 3. And a heating unit 5 disposed at the bottom of the first flow chamber 41 for heating the fuel inside it.

[0036] In some specific embodiments, the heating unit 5 includes: The annular support 51 is located at the bottom of the first flow cavity 41; A plurality of heating elements 52 are arranged circumferentially along the annular support member 51; And a connector 53 that is connected to the heating element 52 and extends outside the main housing 1.

[0037] In some specific embodiments, the connector 53 is used to connect with an external wiring harness connector to achieve a power connection.

[0038] In some specific embodiments, the annular support 51 and the main housing 1 are connected and sealed by a first sealing ring 54; The annular support member 51 is provided with a plurality of screw mounting holes 511, and the annular support member 51 and the main housing 1 are connected by inserting a plurality of screws into the screw mounting holes 511.

[0039] In some specific embodiments, the fuel filter further includes a temperature control unit 6, which includes an electrically connected temperature sensor 61 and a controller 62. The temperature control unit 6 is mounted on the annular support 51 and is connected to the heating element 52 and the connector 53.

[0040] In some specific embodiments, the temperature control unit 6 is configured such that when the temperature sensor 61 detects that the fuel temperature at the fuel inlet 11 is lower than a first preset temperature, the controller 62 controls the heating element 52 to heat; when the temperature sensor 61 detects that the fuel temperature at the fuel inlet 11 is higher than a second preset temperature, the controller 62 controls the heating element 52 to stop heating.

[0041] In some specific embodiments, the first flow cavity 41 includes an annular cavity 411 located on the inner wall of the main housing 1 and the outer wall of the filter element 3, and a water collection cavity 412 located at the bottom of the main housing 1 and below the filter element 3, and the heating unit 5 is installed at the bottom of the water collection cavity 412.

[0042] In some specific embodiments, a drain valve 4121 is provided at the lowest point of the bottom of the water collection cavity 412.

[0043] In some specific embodiments, the central tube 2 further includes: A central tube body 22 with a closed top and connected to the oil outlet 12 at the bottom, wherein the connection port 21 is located at the top of the tube wall of the central tube body 22; A central tube cap 23, located above and connected to the central tube body 22, has an air hole 231 at its top. And several return oil pipelines 24 located on both sides of the central tube body 22, the top of which are connected to the air hole 231.

[0044] In some specific embodiments, the main housing 1 is also provided with an oil return port 13, and the oil return pipeline 24 is connected to the oil return port 13.

[0045] In some specific embodiments, the outer wall of the central tube body 22 is provided with a threaded structure 25 arranged along its axial direction. The outer wall of the threaded structure 25 contacts the inner wall of the filter element 3, forming a buffer cavity 26 for storing the fuel filtered by the filter element 3. The central tube 2 and the filter element 3 are not an integral structure, but are separately detachable structures.

[0046] In some specific embodiments, the lower end of the central tube body 22 is sealed to the main housing 1 by a second sealing ring 221.

[0047] In some specific embodiments, the lower end of the central tube 2 is sealed to the main housing 1 by a third sealing ring 27.

[0048] In some specific embodiments, the top of the main housing 1 is connected to a top cover plate 7.

[0049] In some specific embodiments, the main housing 1 and the upper cover 7 are detachably connected by threads.

[0050] In some specific embodiments, a filter element cover 31 is fixedly connected to the top of the filter element 3, and the filter element cover 31 is detachably connected to the upper cover plate 7.

[0051] Each of the above embodiments can be implemented individually or in any combination of two or more.

[0052] The following description uses specific examples to illustrate the point.

[0053] Example 1 like Figure 1 As shown, a fuel filter includes: The main housing 1 is provided with an oil inlet 11 and an oil outlet 12; The central tube 2 located inside the main housing 1 has a connection port 21 on its tube wall; A filter element 3 located inside the main housing 1 and surrounding the central tube 2, the filter element 3 being used to filter fuel; A plurality of flow chambers 4 located inside the main housing 1 and used for fuel flow include a first flow chamber 41 and a second flow chamber 42. The first flow chamber 41 is a cavity formed between the inner wall of the main housing 1 and the outer surface of the filter element 3. The second flow chamber 42 is a tubular cavity formed by the inner cavity of the central tube 2. The first flow chamber 41 is connected to the oil inlet 11, and the second flow chamber 42 is connected to the oil outlet 12. The second flow chamber 42 communicates with the first flow chamber 41 through the connecting port 21 and the filter element 3. And a heating unit 5 disposed at the bottom of the first flow chamber 41 for heating the fuel inside it.

[0054] In this embodiment, as Figure 2 and 3 As shown, the heating unit 5 includes: The annular support 51 is located at the bottom of the first flow cavity 41; Three heating elements 52 are arranged circumferentially along the annular support member 51; And a connector 53 that is connected to the heating element 52 and extends outside the main housing 1.

[0055] In this embodiment, the connector 53 is used to connect with an external wiring harness connector to achieve power connection.

[0056] In this embodiment, the annular support 51 and the main housing 1 are connected and sealed by a first sealing ring 54; The annular support member 51 is provided with a plurality of screw mounting holes 511, and the annular support member 51 and the main housing 1 are connected by inserting a plurality of screws into the screw mounting holes 511.

[0057] In this embodiment, the first flow cavity 41 includes an annular cavity 411 located on the inner wall of the main housing 1 and the outer wall of the filter element 3, and a water collection cavity 412 located at the bottom of the main housing 1 and below the filter element 3. The heating unit 5 is installed at the bottom of the water collection cavity 412.

[0058] In this embodiment, a drain valve 4121 is provided at the lowest point of the bottom of the water collection cavity 412.

[0059] In this embodiment, the operation procedure of the fuel filter is as follows: Under normal conditions, fuel enters through the inlet 11, flows into the first flow chamber 41, first into the annular cavity 411, and then into the water collection chamber 412. Under pressure, the fuel penetrates the filter element 3 from the outside in. Solid impurities are intercepted by the filter element 3 during this process, while water and heavy impurities gradually settle and accumulate in the bottom water collection chamber 412 due to gravity. When a large amount of water accumulates, the drain valve 4121 is manually opened periodically to directly discharge the accumulated water and contaminants from the fuel filter. Clean fuel, after passing through the filter element 3, enters the second flow chamber 42 through the connection port 21 on the wall of the central tube 2, and then flows to the outlet 12.

[0060] When the fuel temperature drops to its freezing point, the formed wax crystals can clog the fuel lines, affecting normal fuel supply and consequently impacting engine operation. The heating unit 5, located at the bottom of the first flow chamber 41, heats the condensed fuel. During heating, heat is transferred from bottom to top, and because the heating elements are arranged in a ring, the entire fuel within the first flow chamber 41 is affected by heat, resulting in high thermal efficiency. This quickly melts the paraffin crystals that precipitate at low temperatures, preventing localized undissolved wax buildup. Preheating the fuel before it enters the filter element prevents wax buildup and ensures unobstructed filtration, guaranteeing a continuous supply of clean fuel to the engine even in cold environments, thus ensuring normal vehicle or equipment start-up and operation.

[0061] Example 2 This embodiment is based on embodiment 1 with some modifications, such as... Figure 4 and 5 As shown, the fuel filter also includes a temperature control unit 6, which includes a temperature sensor 61 and a controller 62 that are electrically connected. The temperature control unit 6 is mounted on the annular support 51 and is connected to the heating element 52 and the connector 53.

[0062] In this embodiment, the temperature control unit 6 is configured such that when the temperature sensor 61 detects that the fuel temperature at the fuel inlet 11 is lower than a first preset temperature, the controller 62 controls the heating element 52 to heat; when the temperature sensor 61 detects that the fuel temperature at the fuel inlet 11 is higher than a second preset temperature, the controller 62 controls the heating element 52 to stop heating. Without manual intervention, the system automatically monitors, judges, and executes heating commands, providing a good user experience. Heating is only initiated at a low temperature when needed and stops once a suitable temperature is reached, avoiding continuous energy waste. This prevents excessively high fuel temperatures and improves the safety of the entire fuel supply system.

[0063] In this embodiment, the controller 62 is a PLC controller.

[0064] Example 3 This embodiment is based on embodiment 1, and the central tube 2 further includes: A central tube body 22 with a closed top and connected to the oil outlet 12 at the bottom, wherein the connection port 21 is located at the top of the tube wall of the central tube body 22; A central tube cap 23, located above and connected to the central tube body 22, has an air hole 231 at its top. And two return oil pipelines 24 located on both sides of the central tube body 22, the top of which are connected to the air hole 231.

[0065] In this embodiment, the main housing 1 is also provided with an oil return port 13, and the oil return pipeline 24 is connected to the oil return port 13.

[0066] In this embodiment, the lower end of the central tube body 22 is sealed to the main housing 1 by a second sealing ring 221.

[0067] In this embodiment, the lower end of the central tube 2 is sealed to the main housing 1 by a third sealing ring 27.

[0068] In this embodiment, the operation procedure of the fuel filter is as follows: Under normal conditions, fuel enters through the inlet 11, flows into the first flow chamber 41, first into the annular cavity 411, and then into the water collection chamber 412. Under pressure, the fuel penetrates the filter element 3 from the outside in. Solid impurities are intercepted by the filter element 3 during the process, while water and heavy impurities gradually settle downwards and accumulate in the bottom water collection chamber 412 due to gravity. When a large amount of water accumulates, the drain valve 4121 is opened manually periodically to drain the accumulated water and dirt directly from the fuel filter. After passing through the filter element 3, the clean fuel enters the second flow chamber 42 through the connection port 21 on the wall of the central tube 2, and then flows to the outlet 12. Air and fuel vapor from the upper part of the filter element enter through the vent 231 of the central tube cover 23, then enter the return oil line 24 connected to it, and finally return to the fuel tank through the return oil port 13. This built-in exhaust and return oil system can automatically eliminate the air resistance phenomenon in the fuel filter, ensuring a continuous and stable fuel supply and preventing the engine from losing power or stalling due to air mixing in the fuel system. By integrating multiple functions into a single central tube component, the fuel filter boasts a highly compact overall structure, eliminating the need for complex external exhaust circuits.

[0069] When the fuel temperature drops to its freezing point, the formed wax crystals can clog the fuel lines, affecting normal fuel supply and consequently impacting engine operation. The heating unit 5, located at the bottom of the first flow chamber 41, heats the condensed fuel. During heating, heat is transferred from bottom to top, and because the heating elements are arranged in a ring, the entire fuel within the first flow chamber 41 is affected by heat, resulting in high thermal efficiency. This quickly melts the paraffin crystals that precipitate at low temperatures, preventing localized undissolved wax buildup. Preheating the fuel before it enters the filter element prevents wax buildup and ensures unobstructed filtration, guaranteeing a continuous supply of clean fuel to the engine even in cold environments, thus ensuring normal vehicle or equipment start-up and operation.

[0070] Example 4 This embodiment is based on embodiment 3 with some modifications, such as... Figures 6-11 As shown, the outer wall of the central tube body 22 is provided with a threaded structure 25 arranged along its axial direction. The outer wall of the threaded structure 25 contacts the inner wall of the filter element 3, forming a buffer cavity 26 for storing the fuel filtered by the filter element 3. The central tube 2 and the filter element 3 are not an integral structure, but are separately detachable structures.

[0071] Under normal conditions, fuel enters through the inlet 11, flows into the first flow chamber 41, first into the annular cavity 411, and then into the water collection chamber 412. Under pressure, the fuel penetrates the filter element 3 from the outside in. Solid impurities are intercepted by the filter element 3 during the process, while water and heavy impurities gradually settle downwards and accumulate in the bottom water collection chamber 412 due to gravity. When a large amount of water accumulates, the drain valve 4121 is opened manually periodically to directly discharge the accumulated water and dirt from the fuel filter. After passing through the filter element 3, the clean fuel first enters the buffer cavity 26 formed by the threaded structure 25. When the fuel level reaches the height of the connection port 21, it enters the second flow chamber 42 through the connection port 21 and then flows to the outlet 12. Air and fuel vapor from the upper part of the filter element enter through the vent 231 of the central tube cover 23, then enter the connected return oil line 24, and finally return to the fuel tank through the return oil port 13. This built-in exhaust and return oil system can automatically eliminate vapor lock in the fuel filter, ensuring a continuous and stable fuel supply and preventing engine power loss or stalling due to air mixing in the fuel system. Integrating multiple functions into a single central tube component makes the overall structure of the fuel filter very compact, eliminating the need for a complex external exhaust circuit.

[0072] When the fuel temperature drops to its freezing point, the formed wax crystals can clog the fuel lines, affecting normal fuel supply and consequently impacting engine operation. The heating unit 5, located at the bottom of the first flow chamber 41, heats the condensed fuel. During heating, heat is transferred from bottom to top, and because the heating elements are arranged in a ring, the entire fuel within the first flow chamber 41 is affected by heat, resulting in high thermal efficiency. This quickly melts the paraffin crystals that precipitate at low temperatures, preventing localized undissolved wax buildup. Preheating the fuel before it enters the filter element prevents wax buildup and ensures unobstructed filtration, guaranteeing a continuous supply of clean fuel to the engine even in cold environments, thus ensuring normal vehicle or equipment start-up and operation.

[0073] Example 5 This embodiment is based on embodiment 4 with some modifications, such as... Figure 12 As shown, the top of the main housing 1 is connected to an upper cover plate 7.

[0074] In this embodiment, the main housing 1 and the upper cover 7 are detachably connected by threads.

[0075] In this embodiment, a filter element cover 31 is fixedly connected to the top of the filter element 3, and the filter element cover 31 is detachably connected to the upper cover plate 7.

[0076] In this embodiment, when the filter element 3 needs to be replaced, the filter element 3 can be taken out by opening the upper cover plate 7 and then the filter element 3 can be replaced. There is no need to replace the central tube 2 at the same time, which greatly reduces the long-term use cost for users.

[0077] Example 6 A fuel filter, comprising: The main housing 1 is provided with an oil inlet 11 and an oil outlet 12; The central tube 2 located inside the main housing 1 has a connection port 21 on its tube wall; A filter element 3 located inside the main housing 1 and surrounding the central tube 2, the filter element 3 being used to filter fuel; A plurality of flow chambers 4 located inside the main housing 1 and used for fuel flow include a first flow chamber 41 and a second flow chamber 42. The first flow chamber 41 is a cavity formed between the inner wall of the main housing 1 and the outer surface of the filter element 3. The second flow chamber 42 is a tubular cavity formed by the inner cavity of the central tube 2. The first flow chamber 41 is connected to the oil inlet 11, and the second flow chamber 42 is connected to the oil outlet 12. The second flow chamber 42 communicates with the first flow chamber 41 through the connecting port 21 and the filter element 3. And a heating unit 5 disposed at the bottom of the first flow chamber 41 for heating the fuel inside it.

[0078] In this embodiment, the heating unit 5 includes: The annular support 51 is located at the bottom of the first flow cavity 41; Three heating elements 52 are arranged circumferentially along the annular support member 51; And a connector 53 that is connected to the heating element 52 and extends outside the main housing 1.

[0079] In this embodiment, the connector 53 is used to connect with an external wiring harness connector to achieve power connection.

[0080] In this embodiment, the annular support 51 and the main housing 1 are connected and sealed by a first sealing ring 54; The annular support member 51 is provided with a plurality of screw mounting holes 511, and the annular support member 51 and the main housing 1 are connected by inserting a plurality of screws into the screw mounting holes 511.

[0081] In this embodiment, the fuel filter further includes a temperature control unit 6, which includes a temperature sensor 61 and a controller 62 that are electrically connected. The temperature control unit 6 is mounted on the annular support 51 and is connected to the heating element 52 and the connector 53.

[0082] In this embodiment, the temperature control unit 6 is configured such that when the temperature sensor 61 detects that the fuel temperature at the fuel inlet 11 is lower than a first preset temperature, the controller 62 controls the heating element 52 to heat; and when the temperature sensor 61 detects that the fuel temperature at the fuel inlet 11 is higher than a second preset temperature, the controller 62 controls the heating element 52 to stop heating.

[0083] In this embodiment, the first flow cavity 41 includes an annular cavity 411 located on the inner wall of the main housing 1 and the outer wall of the filter element 3, and a water collection cavity 412 located at the bottom of the main housing 1 and below the filter element 3. The heating unit 5 is installed at the bottom of the water collection cavity 412.

[0084] In this embodiment, a drain valve 4121 is provided at the lowest point of the bottom of the water collection cavity 412.

[0085] In this embodiment, the central tube 2 further includes: A central tube body 22 with a closed top and connected to the oil outlet 12 at the bottom, wherein the connection port 21 is located at the top of the tube wall of the central tube body 22; A central tube cap 23, located above and connected to the central tube body 22, has an air hole 231 at its top. And several return oil pipelines 24 located on both sides of the central tube body 22, the top of which are connected to the air hole 231.

[0086] In this embodiment, the main housing 1 is also provided with an oil return port 13, and the oil return pipeline 24 is connected to the oil return port 13.

[0087] In this embodiment, the outer wall of the central tube body 22 is provided with a threaded structure 25 arranged along its axial direction. The outer wall of the threaded structure 25 contacts the inner wall of the filter element 3, forming a buffer cavity 26 for storing the fuel filtered by the filter element 3. The central tube 2 and the filter element 3 are not an integral structure, but are separately detachable structures.

[0088] In this embodiment, the lower end of the central tube body 22 is sealed to the main housing 1 by a second sealing ring 221.

[0089] In this embodiment, the lower end of the central tube 2 is sealed to the main housing 1 by a third sealing ring 27.

[0090] In this embodiment, the top of the main housing 1 is connected to an upper cover plate 7.

[0091] In this embodiment, the main housing 1 and the upper cover 7 are detachably connected by threads.

[0092] In this embodiment, a filter element cover 31 is fixedly connected to the top of the filter element 3, and the filter element cover 31 is detachably connected to the upper cover plate 7.

[0093] The above description of the embodiments is provided to enable those skilled in the art to understand and use the utility model. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present utility model is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present utility model without departing from its scope should be within the protection scope of the present utility model.

Claims

1. A fuel filter, characterized in that, include: The main housing (1) is provided with an oil inlet (11) and an oil outlet (12). The central tube (2) located inside the main housing (1) has a connection port (21) on its tube wall. A filter element (3) located inside the main housing (1) and surrounding the central tube (2) is used to filter fuel. A plurality of flow chambers (4) located inside the main housing (1) and used for fuel flow include a first flow chamber (41) and a second flow chamber (42). The first flow chamber (41) is a cavity formed between the inner wall of the main housing (1) and the outer surface of the filter element (3). The second flow chamber (42) is a tubular cavity formed by the inner cavity of the central tube (2). The first flow chamber (41) is connected to the oil inlet (11). The second flow chamber (42) is connected to the oil outlet (12). The second flow chamber (42) communicates with the first flow chamber (41) through the connection port (21) and the filter element (3). And a heating unit (5) disposed at the bottom of the first flow chamber (41) for heating the fuel inside it.

2. The fuel filter according to claim 1, characterized in that, The heating unit (5) includes: An annular support (51) located at the bottom of the first flow cavity (41); A plurality of heating elements (52) are arranged circumferentially along the annular support (51); And a connector (53) that is connected to the heating element (52) and extends outside the main housing (1).

3. A fuel filter according to claim 2, characterized in that, The annular support (51) and the main housing (1) are connected and sealed by a first sealing ring (54); The annular support (51) is provided with a plurality of screw mounting holes (511), and the annular support (51) and the main housing (1) are connected by inserting a plurality of screws into the screw mounting holes (511).

4. A fuel filter according to claim 2, characterized in that, The fuel filter also includes a temperature control unit (6), which includes an electrically connected temperature sensor (61) and a controller (62). The temperature control unit (6) is mounted on the annular support (51) and is connected to the heating element (52) and the connector (53).

5. A fuel filter according to claim 4, characterized in that, The temperature control unit (6) is configured such that when the temperature sensor (61) detects that the fuel temperature at the inlet (11) is lower than the first preset temperature, the controller (62) controls the heating element (52) to heat; when the temperature sensor (61) detects that the fuel temperature at the inlet (11) is higher than the second preset temperature, the controller (62) controls the heating element (52) to stop heating.

6. A fuel filter according to claim 1, characterized in that, The first flow chamber (41) includes an annular cavity (411) located on the inner wall of the main housing (1) and the outer wall of the filter element (3) and a water collection chamber (412) located at the bottom of the main housing (1) and below the filter element (3), and the heating unit (5) is installed at the bottom of the water collection chamber (412).

7. A fuel filter according to claim 6, characterized in that, A drain valve (4121) is provided at the lowest point of the bottom of the water collection chamber (412).

8. A fuel filter according to claim 1, characterized in that, The central tube (2) also includes: A central tube body (22) with its top closed and its bottom connected to the oil outlet (12), wherein the connection port (21) is located at the top of the tube wall of the central tube body (22); The central tube cap (23) located above and connected to the central tube body (22) has an air hole (231) at its top. And several return oil pipelines (24) located on both sides of the central tube body (22), the top of which is connected to the air hole (231).

9. A fuel filter according to claim 8, characterized in that, The main housing (1) is also provided with an oil return port (13), and the oil return pipeline (24) is connected to the oil return port (13).

10. A fuel filter according to claim 8, characterized in that, The outer wall of the central tube body (22) is provided with a threaded structure (25) arranged along its axial direction. The outer wall of the threaded structure (25) is in contact with the inner wall of the filter element (3) to form a buffer cavity (26) for storing the fuel filtered by the filter element (3).

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