CN114458786A

CN114458786A - Bypass temperature-sensing valve, fuel filter and engine oil supply system

Info

Publication number: CN114458786A
Application number: CN202210141430.XA
Authority: CN
Inventors: 尹燕升; 张驰; 朱宏志; 张贵华; 郭平
Original assignee: FAW Jiefang Automotive Co Ltd
Current assignee: FAW Jiefang Automotive Co Ltd
Priority date: 2022-02-16
Filing date: 2022-02-16
Publication date: 2022-05-10
Anticipated expiration: 2042-02-16
Also published as: CN114458786B

Abstract

The invention relates to the field of vehicles and discloses a bypass temperature control valve, a fuel filter and an engine oil supply system. According to the bypass temperature control valve, the fuel filter and the engine oil supply system, the temperature change in the oil cavity before filtration is accurately sensed through the temperature sensing wax valve, when the temperature in the oil cavity before filtration is reduced, the extension length of the push rod is short, the push rod drives the sealing rod to axially move and gradually approach the temperature sensing wax valve, so that the external oil port is communicated with the oil outlet, fuel in the fuel filter can directly enter the oil outlet channel through the bypass temperature control valve when wax precipitation of the fuel is realized, and the flow resistance of the fuel is reduced. When the temperature in the oil cavity before filtering rises, the extension length of the push rod is gradually increased, and the push rod pushes the sealing rod to move axially and gradually keep away from the temperature sensing wax valve, so that the external oil port and the oil outlet are disconnected.

Description

Bypass temperature-sensing valve, fuel filter and engine oil supply system

Technical Field

The invention relates to the field of vehicles, in particular to a bypass temperature control valve, a fuel filter and an engine oil supply system.

Background

For a diesel vehicle, a high-pressure oil pump pumps diesel oil in an oil tank to an engine, the commonly used diesel oil is zero-grade diesel oil which has the characteristic of waxing in a low-temperature environment, and the diesel oil in the oil tank and the zero-grade diesel oil in an oil supply oil path from the oil tank to the engine are waxed, so that the diesel vehicle has the defects of difficult starting and even incapability of starting in the low-temperature environment. The fuel oil filter is arranged on the fuel supply oil way, and diesel oil is filtered through the fuel oil filter, so that the situation that impurities in the diesel oil block the fuel injection pump is avoided. When the engine is started at low temperature, the diesel oil passes through a filter element of the filter due to wax precipitation of the diesel oil, so that the resistance is very high, and the starting efficiency of the engine is influenced.

Disclosure of Invention

The invention aims to provide a bypass temperature control valve, a fuel filter and an engine oil supply system, which can solve the problem that the filter influences the starting of an engine when diesel oil is subjected to low-temperature wax precipitation.

In order to achieve the purpose, the invention adopts the following technical scheme:

a bypass temperature control valve is used for a fuel filter; the bypass thermo valve includes:

the fuel filter comprises a valve body, wherein an external oil port and an oil outlet are arranged on the valve body, the external oil port is used for communicating with a pre-filtering oil cavity of the fuel filter, and the oil outlet is used for communicating with an oil outlet channel of the fuel filter;

the temperature sensing wax valve is in contact with the fuel in the pre-filtering oil cavity, so that when the temperature of the fuel in the pre-filtering oil cavity is not higher than a preset temperature, the temperature sensing wax valve contracts to enable the sealing rod to axially move in the valve body, the external oil port is communicated with the oil outlet, and when the temperature of the fuel in the pre-filtering oil cavity is higher than the preset temperature, the sealing rod axially moves in the valve body through expansion, and the external oil port is disconnected with the oil outlet.

Optionally, the bypass thermostatic valve further comprises:

the valve body is provided with a sealing rod, the sealing rod is sleeved with a lining, the lining is sleeved outside the sealing rod and fixed in the valve body, the lining is provided with an internal oil port communicated with the external oil port, and the sealing rod is in axial sliding fit with the inner wall of the lining.

Optionally, the fit clearance between the inner wall of the bushing and the outer wall of the sealing rod is 10 μm to 50 μm.

Optionally, both ends of the sealing rod are respectively in sliding fit with the inner wall of the bushing and the inner wall of the valve body.

Optionally, the fit clearance between the outer wall of the sealing rod and the inner wall of the valve body is 0.2mm to 1 mm.

Optionally, the valve body is an aluminum casting.

Optionally, the bypass thermostatic valve further comprises:

a temperature control elastic reset member for making the sealing rod have a tendency to move to a position where the external oil port and the oil outlet are communicated.

Optionally, an assembly space for installing the temperature control elastic reset piece is arranged in the valve body, and a pressure relief hole communicated with the assembly space is formed in the valve body and used for communicating a pre-filtering oil cavity of the fuel filter.

The invention also provides a fuel filter, which comprises the bypass temperature control valve in any scheme, and the fuel filter also comprises:

the filter comprises a filter shell and a filter element, wherein the filter element is arranged in the filter shell and divides an inner cavity of the filter shell into a pre-filter oil cavity and a post-filter oil cavity; an oil inlet of the bypass temperature control valve is communicated with the pre-filtering oil cavity, and an oil outlet of the bypass temperature control valve is communicated with an oil outlet channel of the fuel oil filter.

The invention also provides an engine oil supply system which comprises the fuel oil filter.

The invention has the beneficial effects that: according to the bypass temperature control valve, the fuel filter and the engine oil supply system, the temperature change in the oil cavity before filtration is accurately sensed through the temperature sensing wax valve, when the temperature in the oil cavity before filtration is reduced, the extension length of the push rod is short, the push rod drives the sealing rod to axially move and gradually approach the temperature sensing wax valve, so that the external oil port is communicated with the oil outlet, fuel in the fuel filter can directly enter the oil outlet channel through the bypass temperature control valve when wax precipitation of the fuel is realized, and the flow resistance of the fuel is reduced. When the temperature in the oil cavity before filtering rises, the extension length of the push rod is gradually increased, and the push rod pushes the sealing rod to move axially and gradually keep away from the temperature sensing wax valve, so that the external oil port and the oil outlet are disconnected.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.

FIG. 1 is a cross-sectional view of a fuel filter according to one embodiment of the present invention;

FIG. 2 is a schematic diagram of a temperature control device according to a first embodiment of the present invention;

FIG. 3 is a schematic diagram of a temperature control device provided in accordance with another embodiment of the present invention;

FIG. 4 is a front view of the upper cover according to the first embodiment of the present invention;

FIG. 5 is a cross-sectional view of a cover according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a fuel filter according to one embodiment of the present invention;

FIG. 7 is a schematic view of a bypass thermostatic valve with a sealing stem in a low temperature communication position according to an embodiment of the present invention;

FIG. 8 is a schematic view of a bypass thermostatic valve with a sealing rod in an adaptive temperature blocking position according to an embodiment of the present invention;

FIG. 9 is a side view of a bypass thermostatic valve provided in accordance with an embodiment of the present invention;

FIG. 10 is a cross-sectional view of a venturi configuration provided in accordance with an embodiment of the present invention;

FIG. 11 is a top view of a venturi configuration provided in accordance with an embodiment of the present invention;

FIG. 12 is a schematic view of a venting feature provided in accordance with an embodiment of the present invention;

FIG. 13 is a schematic view of a portion of a venting structure provided in accordance with an embodiment of the present invention;

FIG. 14 is a schematic view of the interior of the upper cover according to the first embodiment of the present invention;

FIG. 15 is a graph comparing the analysis results of finite element analysis of the upper cover according to the first embodiment of the present invention and the existing upper cover;

fig. 16 to 20 are state diagrams of the bypass thermo-valve when the sealing rod according to the second embodiment of the present invention moves from the low temperature communication position to the high temperature relief position.

In the figure:

1. a filter housing; 11. an upper cover; 111. an external thread; 112. sealing the groove; 113. a limiting boss; 114. a top vent; 115. a first annular boss; 116. a second annular boss; 117. a first inner reinforcing rib; 118. a second inner reinforcing rib; 119. an outer reinforcing rib; 12. a housing main body;

2. a filter element; 21. a top cover; 22. mounting a bracket; 23. a filter element main body; 24. a base;

3. bypassing the temperature control valve; 31. a valve body; 311. an outer oil port; 312. an oil outlet; 313. a pressure relief vent; 314. a valve housing; 3141. temperature control clamping protrusions; 315. a valve cover; 3151. a temperature control clamp hole; 32. a sealing rod; 33. a temperature sensitive wax valve; 331. a sensing end; 332. a push rod; 34. a temperature control elastic reset member; 35. a bushing; 351. an internal oil port; 36. an assembly space; 37. a temperature controlled sealing member;

4. a temperature control device; 41. a temperature detection unit; 42. a heating unit; 43. a temperature control module; 44. a relay; 441. a state feedback terminal; 442. a first terminal; 443. a second terminal; 444. an electromagnetic trigger switch; 445. a positive electrical terminal; 446. a negative electrical terminal;

5. a thermal insulation member; 6. an exhaust structure; 61. an oil discharge pipe; 611. a third prevention swing part; 62. an exhaust pipe; 621. a top gas pipe; 6211. a first swing prevention portion; 622. a bottom gas pipe; 6221. an exhaust through hole; 6222. a second swing prevention portion; 63. a venturi passage;

71. a guide housing; 711. a gas guide channel; 72. a guide seal; 73. an elastic plate; 74. an exhaust valve; 741. a vent seal; 75. a guiding elastic reset piece;

100. a pre-filter oil chamber; 200. a filtered oil cavity; 300. a bypass oil passage; 400. a top gas chamber; 500. an air guide channel.

Detailed Description

In order to make the technical problems solved, the technical solutions adopted and the technical effects achieved by the present invention clearer, the technical solutions of the present invention are further described below by way of specific embodiments with reference to the accompanying drawings. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some but not all of the elements associated with the present invention are shown in the drawings.

The present embodiment provides an engine oil supply system for supplying fuel in a fuel tank to an engine, where the fuel is diesel fuel. The engine oil supply system comprises a preheater, an electric pump and a high-pressure oil pump, wherein the preheater can select the electric heater for heating a small amount of solidified diesel oil near the inlet of the electric pump so as to liquefy the solid fuel oil when the engine is started under the condition that the diesel oil in an oil tank is waxed. After the electric pump builds pressure, the liquid fuel around the electric pump is pushed to the engine through the high-pressure oil pump and returns to the oil tank through the oil return pipe, so that the solid fuel in the circulating oil way is replaced by the liquid fuel, then the engine can be started normally, because the oil return temperature of the engine is higher, the oil returned by the engine can be led to the position near the inlet of the electric pump, and the fluidization of the solid fuel in the oil tank is realized by utilizing the heat provided by the oil returned by the engine. Compared with the prior art that the problem of low-temperature starting of the engine is solved by adopting 35# diesel oil, the method can effectively solve the problem that the starting of the engine is influenced when the zero-grade diesel oil is subjected to low-temperature waxing, and can greatly reduce the cost.

In order to avoid clogging of the high-pressure oil pump by impurities in the diesel fuel, a fuel filter is usually provided between the high-pressure oil pump and the electric pump to filter the fuel to be fed to the high-pressure oil pump. However, when diesel oil is waxed, the filter element has waxed fuel oil, so that the resistance when the fuel oil passes through the filter element of the fuel oil filter is large, and the liquid fuel oil provided by the electric pump can not push the solid fuel oil in the fuel oil filter to pass through the filter element. Therefore, the embodiment provides the fuel filter to solve the problem that the filter influences the starting of the engine when the diesel oil is subjected to low-temperature wax precipitation.

As shown in fig. 1, the fuel filter provided by the present embodiment includes a filter housing 1 and a filter element 2, wherein the filter element 2 is installed in the filter housing 1 and divides an inner cavity of the filter housing 1 into a pre-filter oil chamber 100 and a post-filter oil chamber 200; an oil outlet channel communicated with the filtered oil cavity 200 is arranged on the filtering shell 1 and is used for connecting a high-pressure oil pump. Illustratively, the filter element 2 is a hollow structure, the pre-filter oil chamber 100 is formed between the filter element 2 and the inner wall of the filter housing 1, and the post-filter oil chamber 200 is formed in the filter element 2.

As shown in fig. 2, the fuel filter further includes a temperature control device 4, and the temperature control device 4 is used for heating the fuel in the filter housing 1. When the engine is started at a low temperature, the fuel in the filter housing 1 is heated by the temperature control device 4 to melt the solid fuel in the filter housing 1, so that the solid fuel in the filter housing 1 is liquefied. Specifically, the temperature control device 4 includes a temperature detection unit 41, a heating unit 42, a temperature control module 43 and a relay 44, wherein the temperature detection unit 41 is used for detecting the temperature in the fuel filter, and the heating unit 42 is used for heating the fuel in the fuel filter; the temperature control module 43 is used for controlling the heating unit 42 to start and stop according to the detection result of the temperature detection unit 41; the relay 44 includes a positive terminal 445, a negative terminal 446, and a state feedback terminal 441, the relay 44 is configured to supply power to the temperature control module 43 when both the positive terminal 445 and the negative terminal 446 are powered, and the state feedback terminal 441 feeds back a power supply state of the temperature control module 43.

In this embodiment, the temperature detecting unit is a 41 temperature sensor, the heating unit 42 is an electric heater, the heating unit 42 is disposed in the oil chamber 100 before filtration, and the temperature control module 43 and the relay 44 are disposed outside the filtration housing 1. The power supply adopts a 24V low-voltage power supply on the vehicle. In order to improve the heating efficiency of the heating unit 42, the heating unit 42 has an annular structure, so that the heating area is large, and the time consumption for melting the solid fuel is shortened.

In this embodiment, the negative terminal 446 is connected to the negative terminal of the power supply, and the positive terminal 445 is selectively connected to or disconnected from the positive terminal of the power supply. The negative terminal of the temperature control module 43 is connected to the negative pole of the power supply, the relay 44 includes a first terminal 442, a second terminal 443 and an electromagnetic trigger switch 444, the first terminal 442 is connected to the positive terminal of the temperature control module 43, and the second terminal 443 is connected to the positive pole of the power supply; the electromagnetic trigger switch 444 has both ends of a coil connected to a positive terminal 445 and a negative terminal 446, respectively, and is operable to turn on the first terminal 442 and the second terminal 443 when both the positive terminal 445 and the negative terminal 446 are electrically connected, and to turn off the first terminal 442 and the second terminal 443 when at least one of the positive terminal 445 and the negative terminal 446 is electrically disconnected. It should be noted that the electromagnetic trigger switch 444 is prior art and will not be described in detail here.

When the temperature detecting unit 41 detects that the temperature in the fuel filter is lower than the target temperature, it indicates that the fuel will be waxed or has been waxed, in order to avoid wax precipitation of the fuel in the fuel filter increasing the resistance of the fuel in the fuel filter passing through the filter element 2, the positive terminal 445 is conducted with the positive electrode of the power supply, the coil of the electromagnetic trigger switch 444 forms a passage with the power supply, current is generated in the coil, thereby generating electromagnetic force, the iron core of the electromagnetic trigger switch 444 is extended and contracted, so that the first terminal 442 and the second terminal 443 are conducted through the electromagnetic trigger switch 444, the positive electrode of the power supply is conducted with the positive electrode of the temperature control module 43 through the second terminal 443, the first terminal 442 and the positive electrode of the temperature control module 43, at this time, the positive electrode of the temperature control module 43 is conducted with the positive electrode of the power supply, the negative electrode of the temperature control module 43 is conducted with the negative electrode of the power supply, the temperature control module 43 controls the heating unit 42 to start to operate, to heat the fuel in the fuel filter. The state feedback terminal 441 will be able to detect that the voltage of the positive electrode of the temperature control module 43 is 24V at this time, thereby determining that the heating unit 42 is operating.

When the temperature in the fuel filter detected by the temperature detection unit 41 is not lower than the target temperature, it indicates that the fuel does not wax, and the fuel in the fuel filter does not need to be heated, at this time, the positive terminal 445 is disconnected from the positive electrode of the power supply, the electromagnetic trigger switch 444 cannot generate electromagnetic force, the first terminal 442 and the second terminal 443 are disconnected, at this time, the positive electrode of the power supply cannot be conducted with the positive electrode of the temperature control module 43, only the negative electrode of the temperature control module 43 is conducted with the negative electrode of the power supply, and the temperature control module 43 cannot control the heating unit 42 to operate. At this time, the state feedback terminal 441 can detect that the voltage of the positive electrode of the temperature control module 43 is 0V, thereby determining that the heating unit 42 is not operated.

In other embodiments, as shown in FIG. 3, the positive terminal 445 may be connected to the positive pole of the power source and the negative terminal 446 is selectively connected to or disconnected from the negative pole of the power source. When the temperature detecting unit 41 detects that the temperature in the fuel filter is lower than the target temperature, the negative terminal 446 is conducted with the negative electrode of the power supply, so that the temperature control module 43 can control the heating unit 42 to operate. When the temperature detecting unit 41 detects that the temperature in the fuel filter is not lower than the target temperature, the negative terminal 446 is disconnected from the negative electrode of the power supply, so that the temperature control module 43 cannot control the operation of the heating unit 42.

It should be noted that the target temperature may be set according to actual requirements, and optionally, the target temperature is less than or equal to 10 ℃. Preferably, -5 ℃ to a target temperature of 5 ℃. Further, the filter housing 1 comprises an upper cover 11 and a housing main body 12, the upper cover 11 and the housing main body 12 are detachably connected to form a mounting cavity, and the filter element 2 is mounted in the mounting cavity. Since the filter element 2 needs to be replaced periodically, the upper cover 11 and the shell main body 12 are detachably connected, so that the filter element 2 can be replaced conveniently. As shown in fig. 1, 4 and 5, preferably, the upper cover 11 is screwed with the housing main body 12, specifically, the outer peripheral wall of the lower end of the upper cover 11 is provided with an external thread 111, the inner peripheral wall of the upper end of the housing main body 12 is provided with an internal thread, and the external thread 111 on the upper cover 11 is matched with the internal thread on the housing main body 12. In order to prevent fuel leakage, the outer peripheral wall of the lower end of the upper cover 11 is provided with a sealing groove 112, a sealing member is disposed in the sealing groove 112, the sealing member is interposed between the outer peripheral wall of the upper cover 11 and the inner peripheral wall of the case main body 12, and the sealing groove 112 is located above the external thread 111 on the upper cover 11. The outer peripheral wall of the lower end of the upper cover 11 is convexly provided with a limit boss 113, the limit boss 113 is higher than the external thread 111 on the upper cover 11, and when the upper cover 11 and the shell main body 12 are connected by the thread, the shell main body 12 is limited by the limit boss 113.

Further, in practical applications, the fuel filter is arranged vertically, and the liquid level in the fuel filter is usually too low, so that most of the part above the middle of the filter element 2 cannot be used. Therefore, the upper cover 11 is arranged to be of a transparent structure, so that the liquid level and the blocking condition in the filter shell 1 can be conveniently observed, the liquid level in the filter shell 1 meets the requirement, the liquid level in the filter shell 1 cannot be too low, the liquid level in the filter shell 1 cannot be too high, the filter element 2 is fully utilized, and the filtering efficiency of the fuel filter is improved.

Further, the shell main body 12 is an aluminum casting, so that the processing is convenient, the cost is low, the fuel temperature can be gradually increased after the engine works for a period of time, and the aluminum shell main body 12 is adopted, so that the heat dissipation effect is good. In order to reduce the amount of heat loss during operation of the heating unit 42, a heat insulator 5 is provided between the inner wall of the filter housing 1 and the heating unit 42. In this embodiment, the heat insulating member 5 has an annular structure, and the inner peripheral wall of the heat insulating member 5 completely covers the outer peripheral wall of the heating member to improve the heat insulating effect.

Further, as shown in fig. 6, the fuel filter further includes a bypass oil passage 300, one end of the bypass oil passage 300 is communicated with the pre-filtering oil chamber 100, and the other end is communicated with the oil outlet passage; the bypass oil passage 300 can be selectively connected or disconnected according to the temperature inside the pre-filter oil chamber 100. When the engine is started by adopting the method described above under the condition of diesel oil waxing, in order to avoid that the liquid fuel provided by the electric pump cannot push the solid fuel in the fuel filter to pass through the filter element 2 because the resistance of the fuel passing through the filter element 2 is large due to the wax deposition of the fuel, at the moment, the pre-filter oil chamber 100 and the oil outlet channel can be communicated through the bypass oil channel 300, most of the fuel in the pre-filter oil chamber 100 directly enters the oil outlet channel through the bypass oil channel 300, and compared with the condition that the fuel in the pre-filter oil chamber 100 flows through the filter element 2, the post-filter oil chamber 200 and the oil outlet channel, the flow resistance of the fuel is greatly reduced. When the fuel in the oil chamber 100 before filtering does not wax and the fuel passes through, the bypass oil passage 300 is cut off, and the fuel in the oil chamber 100 before filtering enters the oil chamber 200 after filtering through the filter element 2.

By adopting the fuel oil filter provided by the embodiment, the bypass oil channel 300 can be selectively connected or disconnected according to the temperature in the oil cavity 100 before filtration, filtration of fuel oil is neglected when the temperature is lower, and the bypass oil channel 300 is connected, so that the smoothness of an oil path from an electric pump to a high-pressure oil pump is mainly ensured; when the temperature is relatively high and the fuel in the oil cavity 100 before filtration is not waxed, the bypass oil passage 300 is disconnected, so that the fuel is filtered, and meanwhile, the smooth oil passage from the electric pump to the high-pressure oil pump is ensured. In order to shorten the preparation work before starting the engine in a low temperature environment, when the bypass oil passage 300 is communicated due to the wax deposition of the fuel, the heating unit 42 is controlled to operate to heat the fuel in the fuel filter and to cut off the bypass oil passage 300 as soon as possible.

Further, as shown in fig. 4 and 6, in order to achieve automatic opening and closing of the bypass oil passage 300, the fuel filter further includes a bypass thermo valve 3 for selectively opening or closing the bypass oil passage 300 depending on the temperature inside the pre-filter oil chamber 100. In order to reduce the occupied space of the fuel filter, the bypass temperature control valve 3 is arranged in the oil cavity 100 before filtration in the embodiment, optionally, the bypass temperature control valve 3 is arranged in the shell main body 12, and the bypass temperature control valve 3 can be installed in the shell main body 12 through fasteners such as bolts or clamping and the like, so that the replacement is convenient, and the occupied space of the fuel filter is not additionally increased. Illustratively, a temperature control threaded hole is formed in the valve body 31 of the bypass temperature control valve 3, and the bypass temperature control valve 3 is fixed on the housing main body 12 of the fuel filter. The inner diameter of the temperature control threaded hole is 6 mm-12 mm.

As shown in fig. 7 to 9, the bypass thermostatic valve 3 provided by the present embodiment includes a valve body 31, a sealing rod 32 and a temperature-sensitive wax valve 33, wherein an external oil port 311 and an oil outlet 312 are provided on the valve body 31, the external oil port 311 is used for communicating with the pre-filtering oil chamber 100 of the fuel filter, and the oil outlet 312 is used for communicating with the post-filtering oil chamber 200 of the fuel filter. The temperature sensitive wax valve 33 can contact with the fuel in the pre-filter oil chamber 100, so as to contract to axially move the sealing rod 32 in the valve body 31 when the temperature of the fuel in the pre-filter oil chamber 100 is not higher than a preset temperature, so that the external oil port 311 and the oil outlet 312 are communicated, and expand to axially move the sealing rod 32 in the valve body 31 when the temperature of the fuel in the pre-filter oil chamber 100 is higher than the preset temperature, so that the external oil port 311 and the oil outlet 312 are disconnected.

In this embodiment, when the temperature sensitive wax valve 33 drives the sealing rod 32 to move axially in the valve body 31, the sealing rod 32 can be located at a low-temperature communication position and a suitable-temperature blocking position which are sequentially distributed along the axial direction; when the sealing rod 32 is at the low-temperature communication position, the external oil port 311 is communicated with the oil outlet 312; when the sealing rod 32 is at the temperature suitable blocking position, the external oil port 311 and the oil outlet 312 are disconnected. Specifically, the sensing end 331 of the temperature-sensitive wax valve 33 passes through the valve body 31 and extends into the pre-filter oil chamber 100, and the push rod 332 of the temperature-sensitive wax valve 33 is connected with the sealing rod 32. The construction of the temperature sensitive wax valve 33 is well known in the art and will not be described in detail herein. In order to simplify the connection, in this embodiment, the push rod 332 of the temperature sensitive wax valve 33 and the seal rod 32 are inserted. Illustratively, one end of the sealing rod 32 is provided with a wax valve fitting portion into which the push rod 332 of the temperature sensitive wax valve 33 is inserted.

The temperature-sensitive wax valve 33 can accurately sense the temperature change in the pre-filter oil chamber 100, and when the oil temperature in the pre-filter oil chamber 100 is reduced, the push rod 332 drives the sealing rod 32 to axially move and gradually approach the temperature-sensitive wax valve 33, so that the external oil port 311 is communicated with the oil outlet 312. When the oil temperature in the pre-filtering oil chamber 100 rises, the push rod 332 pushes the sealing rod 32 to move axially and gradually away from the temperature sensitive wax valve 33, so as to disconnect the external oil port 311 and the oil outlet 312.

The number of the external oil ports 311 is not less than one, and when the number of the external oil ports 311 is greater than or equal to two, the at least two external oil ports 311 are circumferentially arranged along the valve body 31 at intervals. Illustratively, the number of the outer oil ports 311 is four, and the outer oil ports 311 are arc-shaped holes extending along the circumferential direction of the outer wall of the valve body 31; the flow area of the external oil port 311 is 100mm²～200mm²(ii) a The flow area of oil outlet 312 is 100mm²～200mm²。

Further, when the push rod 332 of the temperature sensitive wax valve 33 and the wax valve matching portion of the sealing rod 32 are connected in an inserting manner, in the process of temperature reduction, the push rod 332 of the temperature sensitive wax valve 33 and the wax valve matching portion of the sealing rod 32 may be separated, so that the sealing rod 32 cannot be automatically reset, and for this reason, the bypass temperature control valve 3 provided in this embodiment further includes a temperature control elastic resetting member 34 for making the sealing rod 32 have a tendency to move to a position where the external oil port 311 and the oil outlet 312 are communicated. Illustratively, temperature controlled elastic return member 34 is a compression spring. In the process of temperature reduction, the temperature control elastic restoring member 34 provides restoring force to gradually move the sealing rod 32 to a position where the external oil port 311 and the oil outlet 312 are communicated, so that the fitting clearance between the push rod 332 of the temperature sensitive wax valve 33 and the wax valve fitting portion of the sealing rod 32 can be appropriately increased. Alternatively, the fitting clearance between the wax valve fitting portion and the push rod 332 of the temperature sensitive wax valve 33 is 0.1mm to 1 mm.

Further, the bypass temperature control valve 3 further includes a bushing 35, the bushing 35 is sleeved outside the sealing rod 32 and fixed in the valve body 31, an inner oil port 351 communicated with the outer oil port 311 is formed in the bushing 35, and the sealing rod 32 is axially matched with the inner wall of the bushing 35 in a sliding manner. In this embodiment, the bushing 35 is provided with internal oil ports 351 corresponding to the external oil ports 311 one by one, the internal oil ports 351 are opposite to the corresponding external oil ports 311, the bushing 35 comprises an oil port section, a bushing limiting section and a reset limiting section which are coaxially and integrally formed, wherein the internal oil ports 351 are arranged on the oil port section, the outer diameter of the oil port section and the outer diameter of the reset limiting section are both smaller than the outer diameter of the bushing limiting section, the inner wall of the valve body 31 is provided with a bushing limiting surface, and the side surface of the bushing limiting section, which is close to one side of the oil port section, abuts against the bushing limiting surface; one end of the temperature control elastic reset piece 34 is sleeved on the reset limiting section and is abutted against the side surface of the bushing limiting section close to one side of the reset limiting section.

Illustratively, the flow area of the internal oil port 351 is 100mm²～200mm²The inner diameter of the bush 35 is 7 mm-15 mm, the wall thickness of the oil port section is 1 mm-3 mm, and the axial length of the oil port section is 6 mm-20 mm; the axial length of the bushing limiting section is 1 mm-5 mm, and the outer diameter of the bushing limiting section is 15 mm-25 mm; the axial length of the reset limiting section is 1 mm-5 mm, and the wall thickness of the bushing limiting section is 1 mm-3 mm.

Further, the sliding fit of the sealing rod 32 and the bushing 35 enables an assembly space 36 to be formed on one side of the inner cavity of the valve body 31, a small amount of fuel enters the assembly space 36 in the sliding fit process of the sealing rod 32 and the bushing 35, and the resetting of the sealing rod 32 at low temperature will be affected as the fuel in the assembly space 36 is gradually increased. For this purpose, a relief hole 313 communicating with the fitting space 36 is provided in the valve body 31, and the relief hole 313 communicates with the pre-filter oil chamber 100.

The bypass thermo valve 3 further includes a thermo sealing member 37 interposed between the outer peripheral wall of the sealing rod 32 and the inner peripheral wall of the bush 35 when the external oil port 311 is disconnected from the oil outlet 312, for preventing oil leakage. Illustratively, the temperature controlled seal 37 is an O-ring seal. In order to ensure the smoothness of the seal rod 32 when sliding relative to the bush 35, the fit clearance between the inner wall of the bush 35 and the outer wall of the seal rod 32 is 50 μm to 1 mm. In other embodiments, since the requirement for the high temperature resistance of the temperature-controlled sealing element 37 is high when the fuel is at a high temperature, the temperature-controlled sealing element 37 may be eliminated, and the fit clearance between the inner wall of the bushing 35 and the outer wall of the sealing rod 32 may be reduced, for example, the fit clearance between the inner wall of the bushing 35 and the outer wall of the sealing rod 32 is 10 μm to 50 μm, and the sealing effect is achieved by controlling the fit clearance.

In order to improve the stability of the sealing rod 32 during axial movement, the two ends of the sealing rod 32 are respectively in sliding fit with the inner wall of the bushing 35 and the inner wall of the valve body 31. The fitting between the seal rod 32 and the valve body 31 is merely for improving the stability of the seal rod 32 when it moves axially, and therefore, no sealing property is required. Therefore, the fitting clearance between the outer wall of the seal rod 32 and the inner wall of the valve body 31 can be increased appropriately, and the machining requirement for the surface accuracy of the inner wall of the valve body 31 can be reduced. Optionally, the fit clearance between the outer wall of the sealing rod 32 and the inner wall of the valve body 31 is 0.2mm to 1 mm. Illustratively, the valve body 31 is made of cast aluminum, so that the valve body is convenient to process and low in cost.

Further, the valve body 31 includes a valve housing 314 and a valve cover 315, and the valve housing 314 and the valve cover 315 are detachably connected to facilitate installation of various components in the valve body 31. In this embodiment, the valve housing 314 and the valve cap 315 are snap-fit. Specifically, five temperature control clamping protrusions 3141 distributed at intervals in the circumferential direction are arranged on the outer circumferential wall of the valve housing 314, temperature control clamping holes 3151 corresponding to the temperature control clamping protrusions 3141 one by one are arranged on the valve cover 315, and the temperature control clamping protrusions 3141 are clamped with the corresponding temperature control clamping holes 3151.

The valve cover 315 is provided with a wax valve through hole, the temperature sensing wax valve 33 comprises a sensing end 331, a first matching section, a second matching section and the push rod 332 which are sequentially arranged along the axial direction of the temperature sensing wax valve, wherein one end of the sensing end 331 penetrates through the wax valve through hole and is arranged in the pre-filtering oil cavity 100, so that the temperature sensing wax valve 33 can accurately sense the temperature in the pre-filtering oil cavity 100; the other end of response end 331 links to each other with first cooperation section and forms the wax valve fitting surface, and the wax valve wear to establish the hole is the shoulder hole, and the inner wall in wax valve wear to establish the hole is formed with the wax valve spacing face towards sealing rod 32, and the spacing face of wax valve and the axial butt of wax valve fitting surface to carry out the axial to temperature sensing wax valve 33 spacing. The fit clearance between the small-diameter hole of the wax valve through hole and the induction end 331 is 0.1 mm-1 mm.

Illustratively, the length of the sensing end 331 is 5mm to 25mm, and the diameter of the sensing end 331 is 7mm to 9 mm; the first matching section is matched with a large-diameter hole of a wax valve through hole, the length of the first matching section is 5-10 mm, and the diameter of the first matching section is 10-15 mm; the second matching section is connected with the push rod 332, the second matching section is matched with the first matching section, the length of the second matching section is 2-5 mm, and the diameter of the second matching section is 7-9 mm; the telescopic length of the push rod 332 is 3 mm-20 mm, and the diameter of the push rod 332 is 2 mm-5 mm.

Furthermore, the sealing rod 32 further comprises a plugging part and a reset limiting part, the plugging part is connected with the reset limiting part through a connecting rod, the wax valve matching part is arranged on one side of the reset limiting part back to the connecting rod, and the wax valve matching part is provided with an inserting hole for inserting the push rod 332; the shutoff portion and bush 35 sliding fit, the one end butt that bush 35 was kept away from to the elasticity piece that resets in the spacing portion that resets. In this embodiment, shutoff portion, connecting rod, spacing portion and the wax valve cooperation portion axial of reseing set gradually and integrated into one piece.

Illustratively, the outer diameter of the plugging part is 7 mm-15 mm, the axial length of the plugging part is 3 mm-20 mm, the plugging part is of a circular ring structure and plays a role in reducing weight, and the wall thickness of the plugging part is 1 mm-2 mm; the outer diameter of the wax valve matching part is 15 mm-25 mm, and the wall thickness of the wax valve matching part is 2 mm-6 mm.

In order to improve the stability of sealing rod 32 axial displacement in-process, the protruding pole portion strengthening rib that is equipped with of periphery wall of connecting rod, pole portion strengthening rib are equipped with a plurality ofly, and the circumference interval distribution of a plurality of pole portion strengthening ribs along the connecting rod. The connecting rod has along its axial first end and the second end that sets up relatively, and first end links to each other and does not bulge in shutoff portion with shutoff portion, and the second end links to each other and does not bulge in the spacing portion that resets with the spacing portion that resets to avoid the strengthening rib to reset the flexible interference that causes of piece 34 to control by temperature change elasticity. Illustratively, the number of the rod reinforcing ribs is four, and the wall thickness of the rod reinforcing ribs is 1 mm-4 mm.

Further, the filter element 2 comprises a top cover 21, a mounting bracket 22, a base 24 and a filter element main body 23, wherein the top cover 21 is connected to the base 24 through the mounting bracket 22, and the filter element main body 23 is mounted on the mounting bracket 22; the top cover 21 is attached to the upper cover 11, and the base 24 is attached to the case main body 12. Preferably, the top cover 21 is detachably attached to the upper cover 11, and the base 24 is detachably attached to the case main body 12. When the filter element 2 needs to be replaced, the mounting bracket 22 for mounting the filter element 2 is only required to be disassembled and assembled. For the fuel filter, the filter element main body 23 may be filter paper, or may be other types of filter elements.

The top wall of the top cover 21 and the inner wall of the upper cover 11 above the top wall enclose a top gas chamber 400, and the top gas chamber 400 is communicated with the pre-filter oil chamber 100. During operation of the fuel filter, the top gas chamber 400 is filled with gas, which may include air, oil mist, etc. Since the fuel may contain air, as the fuel filter continues to operate, the amount of gas above the filter housing 1 increases, directly affecting the amount of fuel that can be contained within the filter housing 1. To this end, the fuel filter of the present embodiment further includes a gas discharge structure 6 for discharging gas in the top gas chamber 400.

As shown in fig. 4, 10 and 11, the air exhausting structure 6 is a venturi structure, the filtered oil chamber 200 communicates with the oil outlet passage through the venturi structure, and an inlet of the venturi structure communicates with the top gas chamber 400. When fuel passes through the Venturi tube structure, negative pressure is formed in the Venturi tube structure, so that gas in the top gas cavity 400 is sucked into the Venturi tube structure and flows to the oil outlet channel along with the fuel, automatic exhaust of the fuel filter is realized, the structure is simple, the cost is low, and fuel waste, air pollution and the like caused by directly discharging the gas in the top gas cavity 400 into the atmosphere can be avoided; the oil mist in the top gas chamber 400 is recycled.

Specifically, the venturi structure includes an exhaust pipe 62 and an oil discharge pipe 61, wherein an upper end inlet of the exhaust pipe 62 is communicated with the top gas cavity 400, the oil discharge pipe 61 is sleeved outside the exhaust pipe 62, a venturi channel 63 is formed between the oil discharge pipe 61 and the exhaust pipe 62, an upper end inlet of the venturi channel 63 is communicated with the post-filter oil cavity 200, and a lower end outlet of the venturi channel 63 is communicated with the oil outlet channel.

When the fuel in the post-filter oil chamber 200 is introduced into the annular region between the exhaust pipe 62 and the oil discharge pipe 61, the flow area of the fuel is reduced, and the flow area of the fuel in the annular region is increased when the fuel enters the oil outlet passage, so that negative pressure is formed in the annular region. The inner hole of the oil discharge pipe 61 can also be a reducing hole, and the aperture of the reducing hole is changed from big to big along the direction from top to bottom; the exhaust pipe 62 may be a stepped pipe with a varying outer diameter, and the outer diameter of the exhaust pipe 62 located in the oil discharge pipe 61 in the direction from top to bottom may be changed from small to large and then smaller. Illustratively, the inner bore of the oil drain pipe 61 is provided as a reduced diameter hole.

The specific exhaust process is as follows: during the operation of the fuel filter, the filtered fuel enters the filtered oil chamber 200 and flows to the oil outlet channel through the venturi channel 63, negative pressure is formed in the venturi channel 63 according to the venturi principle during the fuel flows through the venturi channel 63, the pressure in the top gas chamber 400 is greater than or equal to the atmospheric pressure, and the gas in the top gas chamber 400 enters the venturi channel 63 through the exhaust pipe 62 and enters the oil outlet channel together with the fuel through the venturi channel 63.

It should be noted that the lower end of the exhaust pipe 62 is always located below the liquid level in the post-filter oil chamber 200 during the operation of the fuel filter, so that a negative pressure can be formed in the venturi passage 63 to introduce the gas in the top gas chamber 400 into the venturi passage 63 through the exhaust pipe 62. When the engine is started by adopting the method in the foregoing under the condition of diesel waxing, the venturi structure provided by the embodiment is matched for exhausting, so that an oil path from the oil tank to the engine can be ensured to be in a closed state, and the method in the foregoing for starting the engine can be effectively implemented.

In this embodiment, the side wall of the exhaust pipe 62 is provided with an exhaust through hole 6221 communicating with the venturi passage 63. Specifically, the lower end of the exhaust pipe 62 is disposed through the oil discharge pipe 61, and the side wall of the exhaust pipe 62 forming the venturi channel 63 with the oil discharge pipe 61 is provided with an exhaust through hole 6221, so as to ensure that the gas in the top gas chamber 400 can enter the venturi channel 63 through the exhaust pipe 62 and the exhaust through hole 6221 thereon during the fuel oil flowing through the venturi channel 63.

Further, the length of the exhaust pipe 62 is very long due to the height limitation of the fuel filter, and the pipe processing is inconvenient, for this reason, the exhaust pipe 62 in this embodiment includes a top gas pipe 621 and a bottom gas pipe 622 separately arranged, the upper end of the top gas pipe 621 communicates with the top gas chamber 400, the lower end of the top gas pipe 621 communicates with the upper end of the bottom gas pipe 622, and the lower end of the bottom gas pipe 622 extends into the oil discharge pipe 61 from the upper end of the oil discharge pipe 61. The exhaust pipe 62 is provided separately, so that the difficulty in processing the exhaust pipe 62 can be greatly reduced.

In this embodiment, the upper end of the top air pipe 621 is fixedly connected to the upper end of the filter element 2, and the lower end of the oil drain pipe 61 is fixedly connected to the lower end of the filter element 2. Specifically, top trachea 621 is the rubber tube, is equipped with the perforating hole on the top cap 21 of filter core 2, and the perforating hole is the shoulder hole, and the big footpath section of perforating hole and butt in the ladder surface in the perforating hole are inserted to top trachea 621 to peg graft top trachea 621 with top cap 21. Because the top air pipe 621 is a rubber pipe, the top air pipe 621 and the top cover 21 can be connected in a sealing manner, and a sealing piece is not required to be used. The top air pipe 621 and the top cover 21 are connected in an inserting mode, and the installation mode is simple and quick. The bottom air pipe 622 is a plastic pipe, the base 24 of the filter element 2 is a metal structure, and the lower end of the bottom air pipe 622 can be connected to the base 24 of the filter element 2 in a threaded connection mode.

Further, in order to prevent the bottom air pipe 622 and the top air pipe 621 from swinging, a first swing prevention portion 6211 is interposed between the outer circumferential surface of the exhaust pipe 62 and the inner circumferential surface of the oil discharge pipe 61; the upper end of the exhaust pipe 62 extends out of the oil drain pipe 61, and a second anti-swing portion 6222 is interposed between the outer circumferential surface of the exhaust pipe 62 located outside the oil drain pipe 61 and the inner circumferential surface of the hollow structure. A third prevention swing portion 611 is interposed between the upper end outer circumferential surface of the drain pipe 61 and the inner circumferential surface of the hollow structure in order to prevent the drain pipe 61 from swinging. Specifically, the peripheral wall of the bottom air pipe 622 is convexly provided with a plurality of first anti-swing portions 6211 which are circumferentially spaced apart, the peripheral wall of the top air pipe 621 is convexly provided with a plurality of second anti-swing portions 6222 which are circumferentially spaced apart, and the peripheral wall of the upper end of the oil discharge pipe 61 is convexly provided with a plurality of third anti-swing portions 611 which are circumferentially spaced apart. Note that the first, second, and third

swing prevention portions

6211, 6222, and 611 may be provided for more than one turn. In this embodiment, the vent through hole 6221 is located between the first and second

anti-swing portions

6211 and 6222.

It should be noted that the upper end of the oil drain pipe 61 may be opened to form an inlet of the venturi channel 63, or the top of the oil drain pipe 61 may be sealed, and an oil drain through hole is formed in the oil drain pipe 61, so that the fuel in the post-filter oil chamber 200 enters the oil drain pipe 61 through the oil drain through hole, and at this time, the oil drain through hole is required to be higher than the exhaust through hole 6221. Illustratively, the height difference between the oil drain through hole and the vent through hole 6221 is 5mm to 10mm, and the flow area of the oil drain through hole is 100mm²～300mm²(ii) a The pipe section of the annular area which can form negative pressure and is formed by the inner wall of the oil discharge pipe 61 and the outer wall of the exhaust pipe 62 is marked as a negative pressure pipe section, the outer diameter of the negative pressure pipe section is 10 mm-40 mm, the wall thickness of the negative pressure pipe section is 1 mm-2 mm, and the axial length of the negative pressure pipe section is 5 mm-200 mm; the radial clearance between the inner wall of the negative pressure pipe section and the outer wall of the exhaust pipe 62 is 1 mm-10 mm. The inner diameter of the top air pipe 621 is 2 mm-19 mm, and the wall thickness of the top air pipe 621 is 1 mm-2 mm. The inner diameter of the bottom air pipe 622 is 1 mm-15 mm, and the wall thickness of the bottom air pipe 622 is 1 mm-2 mm; the number of the first anti-swing portions 6211 and the second anti-swing portions 6222 is 4, and the radial thicknesses of the first anti-swing portions 6211 and the second anti-swing portions 6222 are 1mm to 10 mm. The flow area of the vent holes 6221 is 20mm²～200mm². In this embodiment, the upper end of the oil discharge pipe 61 is open to form an inlet of the venturi passage 63.

Further, as shown in fig. 12 and 13, when a filter is inclined, a filter element 2 of the filter is clogged, or the like occurs, fuel in the pre-filter oil chamber 100 and fuel in the post-filter oil chamber 200 may cross each other through the top gas chamber 400, so that the filtering effect of the filter is affected. In order to solve the problem, the fuel filter of the present embodiment further includes a gas guide passage 711, wherein an upper end of the gas guide passage 711 communicates with the top gas chamber 400, and the upper end of the gas guide passage 711 is higher than the top wall of the filter element 2; the upper end of the vent pipe is communicated with the lower end of the gas guide passage 711, and the vent pipe can send the gas in the top gas chamber 400 to the oil outlet passage through the gas guide passage 711. In this embodiment, the vent pipe is the above-mentioned venturi structure. Specifically, the fuel filter further comprises a guide cover 71 and a guide elastic reset piece 75, wherein the guide cover 71 is positioned in the top gas cavity 400, and the gas guide channel 711 is arranged in the guide cover 71; the guide elastic return member 75 serves to press the guide cover 71 against the top wall of the filter element 2, to simplify the fixing of the guide cover 71. In this embodiment, the guiding elastic restoring member 75 is a compression spring, the guiding elastic restoring member 75 is sleeved outside the guiding cover 71, and the guiding elastic restoring member 75 is sandwiched between the inner top wall of the filter housing 1 and the guiding cover 71.

Since the upper end of the gas guide passage 711 is higher than the top wall of the filter element 2, the fuel filter is inclined or clogged, and the possibility of the fuel in the pre-filter oil chamber 100 and the fuel in the post-filter oil chamber 200 crossing each other through the top gas chamber 400 can be reduced to ensure the filtering effect of the fuel filter.

In this embodiment, the gas guide passage 711 is a vertical passage, the upper and lower ends of the guide cover 71 are opened to form the gas guide passage 711, and a guide sealing member 72 is disposed between the lower end surface of the guide cover 71 and the top wall of the filter element 2. Specifically, the inner peripheral surface of the guide sealing member 72 is provided with an annular groove, the lower end of the guide cover 71 is provided with an annular boss, the guide sealing member 72 is sleeved outside the annular boss and enables the annular boss to be inserted into the annular groove, the upper end and the lower end of the guide elastic reset member 75 are respectively abutted to the inner top wall and the annular boss of the filter housing 1, and the annular boss is used for crimping the guide sealing member 72 to the top wall of the filter element 2 to prevent the guide sealing member 72 from loosening. In order to improve the sealing effect, the lower surface of the guide sealing element 72 is provided with two sealing convex rings which are arranged along the radial direction of the guide sealing element 72 in a sleeved mode, and the guide sealing element 72 below the annular groove is clamped between the annular boss and the top wall of the filter element 2, so that the sealing effect is good.

Further, the upper portion of the guide elastic returning member 75 abuts against the filter housing 1, and the lower portion of the guide elastic returning member 75 is fixedly connected to the guide cover 71, so that the guide elastic returning member 75 is prevented from being separated from the filter element 2 when the filter element 2 is maintained. In this embodiment, the upper surface of the annular boss is provided with a plurality of fastening structures distributed at intervals in the circumferential direction, and the guide cover 71 is fastened with the lower end of the guide elastic reset piece 75 through the fastening structures. Specifically, the snap structure is two elastic plates 73 distributed along the radial direction of the annular boss at intervals, the upper parts of the opposite side surfaces of the two elastic plates 73 are convexly provided with anti-falling parts, and the lower end of the guiding elastic reset piece 75 is limited between the two elastic plates 73 below the guiding elastic reset piece through the two anti-falling parts.

Further, the fuel filter also includes a vent valve 74, the vent valve 74 being capable of selectively connecting and disconnecting the top gas chamber 400 from the outside atmosphere. The exhaust valve 74 can be used as a backup, and as described above, when the exhaust structure 6 fails, periodic exhaust can be performed through the exhaust valve 74. In this embodiment, the top of the filter housing 1 is provided with a top vent hole 114, the inner wall of the top vent hole 114 is provided with an internal thread, and the lower end of the vent valve 74 is in threaded connection with the internal thread of the top vent hole 114. Specifically, the exhaust valve 74 includes an exhaust screw plug having a lower end screwed to the internal thread of the top exhaust hole 114, and an operating end of the exhaust screw plug is screwed to communicate the top gas chamber 400 with the external atmosphere through the top exhaust hole 114 when the fuel filter needs to be exhausted. In order to facilitate the operation, the operation end of the exhaust screw plug is of an inner hexagon wrench structure. The operating end can also be provided with a structure convenient for a human hand to directly screw, and is not particularly limited herein.

In order to prevent air leakage, an air-bleeding seal 741 such as an O-ring is interposed between the air-bleeding plug screw and the filter housing 1. Specifically, the outer wall of the exhaust screw plug is provided with an exhaust sealing groove, and an exhaust sealing member 741 is installed in the exhaust sealing groove. Preferably, the exhaust sealing member 741 is located at an upper portion of the top exhaust hole 114, and the internal thread is located at a lower portion of the top exhaust hole 114, so that the exhaust sealing member 741 seals the top exhaust hole 114 and simultaneously seals the top exhaust hole 114 by using the threaded fit between the exhaust valve 74 and the lower portion of the top exhaust hole 114, thereby achieving double sealing and improving sealing effect.

Further, a counter bore is formed at the lower end of the exhaust valve 74, the upper end of the guide cover 71 is inserted into the counter bore, an air guide channel 500 is formed at an interval between the inner wall of the counter bore and the outer wall of the upper end of the guide cover 71, the lower end of the air guide channel 500 is communicated with the top gas chamber 400, and the upper end of the air guide channel 500 is communicated with the gas guide channel 711. Preferably, the air release valve 74 is provided at the highest position of the filter housing 1. With the above arrangement, the height of the upper opening of the gas guide passage 711 can be increased as much as possible, thereby greatly reducing the possibility that the fuel in the pre-filter oil chamber 100 and the fuel in the post-filter oil chamber 200 can cross each other through the top gas chamber 400 during the use of the fuel filter; in consideration of the fact that the fuel filter is vertically installed in the actual use process, the arrangement can substantially prevent the fuel in the pre-filter oil chamber 100 and the fuel in the post-filter oil chamber 200 from being mixed with each other through the top gas chamber 400 due to inclination or shaking in the normal process of the fuel filter. In this embodiment, the upper end of the guiding cover 71 is a tubular air duct, and the top of the air duct is inserted into the counter bore.

Illustratively, the external thread on the vent valve 74 is a B20X 2 buttress thread, which represents a nominal 20mm diameter with a 2mm pitch. The diameter of a counter bore on the exhaust valve 74 is 11mm, the inner diameter of the air guide pipe is 4mm, the outer diameter of the air guide pipe is 8mm, and the gap between the top wall of the guide cover 71 and the inner bottom wall of the counter bore is 2 mm-5 mm.

Further, as shown in fig. 4, 5 and 14, the upper cover 11 of the filter housing 1 includes an upper cover body, and the top vent hole 114 is formed on the upper cover body and penetrates through the top inner and outer walls thereof. In order to meet the installation requirement of the exhaust screw plug, a first annular boss 115 is convexly arranged on the inner top wall of the upper cover body, and an inner hole of the first annular boss 115 forms the top exhaust hole 114.

The first annular boss 115 also has an effect of improving the structural strength of the upper cover 11, and in order to further improve the structural strength of the upper cover 11, a second annular boss 116 which is sleeved outside the first annular boss 115 and is arranged at an interval with the first annular boss 115 is convexly arranged on the inner top wall of the upper cover body. Since the arrangement of the top vent hole 114 may reduce the structural strength of the upper cover 11, for this reason, a first inner reinforcing rib 117 is provided on the inner top wall of the upper cover body, one end of the first inner reinforcing rib 117 is connected to the outer circumferential wall of the first annular boss 115, and the other end is connected to the inner circumferential wall of the second annular boss 116. The inner wall of upper cover body is provided with second inboard strengthening rib 118, and the periphery wall in second annular boss 116 is connected to the one end of second inboard strengthening rib 118, and the other end extends to the inside wall of upper cover 11 along the interior roof of upper cover body. In order to guide the elastic restoring element 75 stably, an annular mounting cavity is formed between the first annular boss 115 and the second annular boss 116, and the upper end of the temperature control elastic restoring element 34 is inserted into the annular mounting cavity and abuts against the first inner reinforcing rib 117.

In order to further improve the structural strength of the upper cover 11, a plurality of outer ribs 119 are provided on the outer wall of the upper cover body so as to be circumferentially spaced apart. The outer rib 119 extends from the outer top wall of the upper cover body to the outer side wall of the upper cover body. The upper cover body, the first inner reinforcing rib 117, the second inner reinforcing rib 118, and the outer reinforcing rib 119 are integrally formed to reduce the cost. The upper cover in the prior art does not have the first inner reinforcing rib 117 connecting the first annular boss 115 and the second annular boss 116, and the upper cover in the prior art and the upper cover 11 provided in this embodiment perform finite element simulation under the oil pressure of 10Bar at 23 ℃. Referring to fig. 15, the first row in fig. 15 is a stress concentration analysis diagram, a strain analysis diagram and a deformation analysis diagram of the existing upper cover, and the second row is a stress concentration analysis diagram, a strain analysis diagram and a deformation analysis diagram of the upper cover 11 provided in this embodiment, respectively, compared with the upper cover in the prior art, the maximum stress concentration of the upper cover 11 provided in this embodiment is reduced from 179.7Mpa to 45.52Mpa, the maximum strain is reduced from 0.103 to 0.025, and the maximum deformation is reduced from 6.96mm to 1.208mm, obviously, the structural strength of the upper cover 11 provided in this embodiment can meet the use requirement better.

The fuel filter described above can be used not only as a coarse filter of an engine oil supply system, but also as a fine filter of the engine oil supply system by replacing the filter element 2 having a higher filtering accuracy.

Example two

As shown in fig. 16 to 20, the difference between the present embodiment and the first embodiment lies in that the pressure relief hole 313 is eliminated, and when the temperature sensitive wax valve 33 drives the sealing rod 32 to axially move in the valve body 31, the sealing rod 32 can be located at a low temperature communication position, a moderate temperature blocking position and a high temperature pressure relief position which are sequentially distributed along the axial direction, wherein when the sealing rod 32 is located at the low temperature communication position, the external oil port 311 is communicated with the oil outlet 312, and the external oil port 311 is disconnected from the assembly space 36; when the sealing rod 32 is at the suitable temperature blocking position, the external oil port 311 and the oil outlet 312 are disconnected, and the external oil port 311 is disconnected from the assembly space 36; when the sealing rod 32 is at the high-temperature pressure relief position, the external oil port 311 and the oil outlet 312 are disconnected and the external oil port 311 is communicated with the assembly space 36.

During normal engine operation, the temperature of the diesel fuel is usually high, and the bypass oil passage 300 is closed. Because diesel oil is usually waxed at low temperature and the engine is not started, and the diesel oil in the fuel oil filter is gradually reduced in the process of engine flameout, although the filter element 2 inevitably has diesel oil, the height of the residual diesel oil liquid level in the fuel oil filter is not high, after the pressure relief hole 313 is cancelled, the installation height of the bypass temperature control valve 3 is adjusted, so that the sealing rod 32 is higher than the diesel oil liquid level in the fuel oil filter when the liquid level in the fuel oil filter is not changed any more after the engine is flameout.

During normal operation of the engine, the sealing rod 32 is in a high-temperature pressure relief position, and the assembly space 36 is communicated with the pre-filter oil chamber 100 through the external oil port 311, so as to prevent the oil pressure in the assembly space 36 from being too high. After the engine is shut down, the sealing rod 32 gradually moves to the proper temperature blocking position as the temperature of the diesel decreases, and even the sealing rod 32 moves to the low temperature communication position in a low temperature environment. Because the process of cooling the diesel oil in the fuel oil filter usually occurs after the engine is shut down, in the process of cooling the diesel oil, the sealing rod 32 is gradually reset, the liquid level of the diesel oil in the fuel oil filter is gradually reduced, when the sealing rod 32 is located at a high-temperature pressure relief position, the external oil port 311 is communicated with the assembly space 36, in the process of resetting the sealing rod 32, the liquid level of the assembly space 36 and the liquid level in the pre-filtration oil cavity 100 are basically located at the same height position, the sealing rod 32 is gradually reset along with the continuous reduction of the temperature in the pre-filtration oil cavity 100, and by limiting the length of the sealing rod 32 and the position of the external oil port 311, most of the diesel oil in the assembly space 36 returns to the pre-filtration oil cavity 100 from the external oil port 311 before the sealing rod 32 moves to the proper-temperature blocking position; when the sealing rod 32 moves to the suitable temperature blocking position, the external oil port 311 and the assembly space 36 are disconnected, at this time, the residual fuel in the assembly space 36 is less, and even if the temperature continues to be reduced to enable the residual fuel in the assembly space 36 to be waxed, the sealing rod 32 cannot be influenced to move to the low temperature communication position.

When the sealing rod 32 moves between the moderate temperature blocking position and the low temperature communication position, the air pressure change in the assembly space 36 is not obvious at low temperature, so that the movement of the sealing rod 32 is basically not influenced, and the pressure relief problem of the assembly space 36 can be avoided. Exemplarily, the temperature in the pre-filter oil chamber 100 is T, as shown in fig. 16, when T is less than or equal to-20 ℃, the sealing rod 32 is in a low-temperature communication position, at this time, the communication opening degree of the external oil port 311 and the oil outlet 312 is the maximum, and the external oil port 311 and the assembly space 36 are completely disconnected; as shown in fig. 17, when-20 ℃ < T < -13 ℃, the external oil port 311 and the oil outlet 312 are partially communicated and the external oil port 311 and the fitting space 36 are completely disconnected; as shown in fig. 18, when T is greater than or equal to-13 ℃ and less than or equal to 25 ℃, the sealing rod 32 is in the suitable temperature blocking position, at this time, the external oil port 311 and the oil outlet 312 are completely disconnected, and the external oil port 311 and the assembly space 36 are completely disconnected; as shown in fig. 19, when T < 80 ℃ is more than 25 ℃, the external oil port 311 is partially communicated with the assembly space 36 and the external oil port 311 is completely disconnected from the oil outlet 312; as shown in FIG. 20, when T is greater than or equal to 80 ℃, the communication opening degree between the external oil port 311 and the assembly space 36 is maximum and the external oil port 311 and the oil outlet 312 are completely disconnected.

It should be noted that the relationship between the position of the sealing rod 32 and the temperature in the pre-filter oil chamber 100 is not limited to the above arrangement, and other arrangements may be adopted, such as the following: when T is less than or equal to minus 10 ℃, the sealing rod 32 is positioned at a low-temperature communication position; when the temperature T is more than minus 10 ℃ and less than 0 ℃, the external oil port 311 is partially communicated with the oil outlet 312, and the external oil port 311 is completely disconnected from the assembly space 36; t is more than or equal to 0 ℃ and less than or equal to 25 ℃, the sealing rod 32 is in a suitable temperature blocking position. When T is less than or equal to 0 ℃, the sealing rod 32 is positioned at a low-temperature communication position, when T is more than 0 ℃ and less than 5 ℃, the external oil port 311 and the oil outlet 312 are partially communicated, and the external oil port 311 and the assembly space 36 are completely disconnected; t is more than or equal to 5 ℃ and less than or equal to 25 ℃, the sealing rod 32 is in a suitable temperature blocking position.

Claims

1. A bypass temperature control valve is used for a fuel filter; characterized in that, bypass temperature-sensing valve includes:

the oil filter comprises a valve body (31), wherein an external oil port (311) and an oil outlet (312) are arranged on the valve body (31), the external oil port (311) is used for being communicated with a pre-filtering oil cavity (100) of the fuel oil filter, and the oil outlet (312) is used for being communicated with an oil outlet channel of the fuel oil filter;

the oil filter comprises a sealing rod (32) and a temperature sensing wax valve (33), wherein the temperature sensing wax valve (33) is in contact with fuel oil in the pre-filtering oil cavity (100) so as to contract when the temperature of the fuel oil in the pre-filtering oil cavity (100) is not higher than a preset temperature to enable the sealing rod (32) to move axially in the valve body (31) to enable the external oil port (311) to be communicated with the oil outlet (312), and expand when the temperature of the fuel oil in the pre-filtering oil cavity (100) is higher than the preset temperature to enable the sealing rod (32) to move axially in the valve body (31) to enable the external oil port (311) to be disconnected from the oil outlet (312).

2. The bypass thermostatic valve of claim 1, further comprising:

the valve body (31) is fixed on the outer side of the sealing rod (32) in the sleeved mode of the lining (35), an inner oil port (351) communicated with the outer oil port (311) is formed in the lining (35), and the sealing rod (32) is in axial sliding fit with the inner wall of the lining (35).

3. The bypass temperature control valve according to claim 2, characterized in that the fit clearance between the inner wall of the bushing (35) and the outer wall of the sealing rod (32) is 10 μm to 50 μm.

4. A by-pass thermo-valve according to claim 2, characterised in that the sealing rod (32) has two ends which are in sliding engagement with the inner wall of the bushing (35) and the inner wall of the valve body (31), respectively.

5. The bypass thermostatic valve according to claim 4, wherein the fit clearance between the outer wall of the sealing rod (32) and the inner wall of the valve body (31) is 0.2mm to 1 mm.

6. A bypass thermo valve according to any of claims 1-5, characterised in that the valve body (31) is a cast aluminium part.

7. The bypass thermostatic valve according to any one of claims 1 to 5, further comprising:

a temperature controlled elastic return member (34) for causing the sealing rod (32) to have a tendency to move to a position where the external oil port (311) and the oil outlet (312) are communicated.

8. The bypass temperature control valve according to claim 7, characterized in that an assembly space (36) for installing the temperature control elastic reset piece (34) is arranged in the valve body (31), and a pressure relief hole (313) communicated with the assembly space (36) is arranged on the valve body (31) and is used for communicating with a pre-filtering oil cavity (100) of a fuel filter.

9. A fuel filter including the bypass thermo valve according to any one of claims 1 to 8, the fuel filter further comprising:

the filter comprises a filter shell (1) and a filter element (2), wherein the filter element (2) is arranged in the filter shell (1), and divides the inner cavity of the filter shell (1) into a pre-filter oil cavity (100) and a post-filter oil cavity (200); an oil inlet of the bypass temperature control valve is communicated with the pre-filtering oil cavity (100), and an oil outlet (312) of the bypass temperature control valve is communicated with an oil outlet channel of the fuel oil filter.

10. An engine oil supply system comprising the fuel filter of claim 9.