Engine preheating and fuel oil circulating heating system and method suitable for extremely cold environment

Abstract

The invention provides an engine preheating and fuel oil circulation heating system suitable for an extremely cold environment. The engine preheating and fuel oil circulation heating system comprises an engine, a cooling liquid heater, an oil tank divided into a main oil cavity and an auxiliary oil cavity, a fuel oil heater and an auxiliary oil cavity oil suction element. The system stores low-grade diesel oil for preheating through the auxiliary oil tank, and stores conventional diesel oil through the main oil tank, so that the cost is reduced. The cooling liquid is heated by the cooling liquid heater, and the diesel oil in the main oil tank is heated by the fuel oil heater through the heated cooling liquid. The system further comprises an oil valve and a driving motor, and oil supply modes of the main oil tank and the auxiliary oil tank can be flexibly switched. In addition, the invention further provides a heating method which comprises the steps of preheating cooling liquid, starting an engine by using low-grade diesel oil, circularly heating and melting wax-deposited diesel oil, switching to conventional diesel oil supply and the like. Compared with the prior art, the method has the remarkable advantages in the aspects of cost effectiveness, engine starting performance, heating efficiency, diesel wax precipitation risk avoiding, system flexibility and the like, and is suitable for stable operation of the engine in the extremely cold environment.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and specifically refers to an engine preheating and fuel circulation heating system and method applicable to extremely cold environments. Background Art

[0002] In extremely cold environments, the start-up and operation of engines face severe challenges. Due to the increased viscosity and poor fluidity of fuel under low-temperature conditions, as well as the property of diesel being prone to waxing, traditional engine preheating and fuel supply methods often struggle to meet the requirements. In addition, although using low-grade diesel in extremely cold regions can improve the low-temperature fluidity of fuel, it is costly, and incomplete combustion will reduce the engine efficiency. Therefore, how to provide an engine preheating and fuel circulation heating system and method applicable to extremely cold environments has become an urgent technical problem to be solved currently.

[0003] Most existing engine preheating systems use methods such as electric heating or flame spraying to preheat the coolant or fuel, but these methods have problems such as high energy consumption, uneven preheating, and low heating efficiency. At the same time, traditional fuel supply systems usually only have one fuel tank, and whether using regular diesel or low-grade diesel, they cannot balance cost-effectiveness and engine performance. Especially in extremely cold regions, using regular diesel can easily lead to difficult engine start-up, while using low-grade diesel is costly, and fuel combustion is incomplete at low temperatures, further reducing the engine efficiency.

[0004] In addition, existing fuel tank designs often do not consider the problem of diesel waxing. Under low-temperature conditions, diesel is prone to waxing at the bottom of the fuel tank, making it difficult for the fuel pump to suck in the waxed diesel at the bottom, thus affecting the normal start-up and operation of the engine. This problem is particularly prominent in extremely cold regions, posing a great risk to the stable operation of the engine.

[0005] In summary, existing engine preheating and fuel supply systems have many technical defects in extremely cold environments and cannot meet the start-up and operation requirements of engines under low-temperature conditions. Therefore, the present invention aims to overcome the above technical defects and provide an engine preheating and fuel circulation heating system and method applicable to extremely cold environments to solve problems such as difficult engine start-up at low temperatures, high fuel costs, and diesel waxing in extremely cold regions. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the above technical defects and provide an engine preheating and fuel circulation heating system and method applicable to extremely cold environments. The purpose of the present invention is to achieve rapid and stable start-up of the engine in extremely cold environments through optimized system design and innovative working methods, while reducing fuel costs and avoiding the risks brought by diesel waxing.

[0007] To solve the above technical problems, the present invention provides an engine preheating and fuel circulation heating system applicable to extremely cold environments, comprising:

[0008] An engine, the cylinder block of which is provided with a coolant chamber and a fuel chamber;

[0009] A coolant heater, which is connected to the coolant chamber through a circulating waterway and is used to heat the coolant in the coolant chamber;

[0010] A fuel tank, which is divided into a main oil chamber and a sub - oil chamber. The sub - oil chamber is used to store low - grade diesel, and the main oil chamber is used to store regular diesel;

[0011] A fuel heater, which is arranged inside the main oil chamber and comprises a heater main body. A circulation chamber that is circularly connected to the coolant chamber and an oil valve that is circularly connected to the fuel chamber are arranged inside the heater main body. A heating element and a main oil chamber oil suction element are arranged below the heater main body. The heating element is connected to the circulation chamber and is used to receive the heated coolant from the coolant chamber and heat the regular diesel in the main oil chamber. The main oil chamber oil suction element is used to pump the regular diesel in the main oil chamber into the oil valve;

[0012] A sub - oil chamber oil suction element, which is arranged inside the sub - oil chamber, is connected to the oil valve and pumps the low - grade diesel in the sub - oil chamber into the oil valve. The oil valve is connected to the fuel chamber, and the oil valve switches the working modes of the sub - oil chamber oil suction element and the main oil chamber oil suction element through a driving motor arranged outside it.

[0013] Further, the coolant heater comprises a heating tank main body, a heating chamber is arranged inside the heating tank main body, and a water pump is further arranged on the heating tank main body. The water inlet of the water pump is connected to the coolant chamber through a water pipe, the water outlet of the water pump is connected to the heating chamber, and the hot water outlet on the heating tank main body returns to the coolant chamber through a circulation pipe.

[0014] Further, the main oil chamber oil suction element comprises a main suction pipe, a main return pipe, and a first filter arranged below the main suction pipe and the main return pipe;

[0015] The sub - oil chamber oil suction element comprises an oil suction main body, a low - grade oil supply port and a low - grade oil return port are arranged above the oil suction main body, a sub - suction pipe and a sub - return pipe are arranged below the oil suction main body, and a second filter is arranged below the sub - suction pipe and the sub - return pipe;

[0016] The oil valve is provided with a first return port, a first supply port, a second return port and a second supply port side by side. The first supply port is connected to the fuel chamber through a first supply pipe, the first return port is connected to the fuel chamber through a first return pipe, the second supply port is connected to the low - grade oil supply port through a second supply pipe, and the second return port is connected to the low - grade oil return port through a second return pipe.

[0017] Furthermore, a heater oil suction pipe is provided below the oil suction main body, a heater oil suction port communicating with the heater oil suction pipe is provided above the oil suction main body, the heater oil suction port is connected to the fuel port on the heating tank main body through a fuel oil pipe, and an oil pump is provided on the fuel oil pipe.

[0018] Furthermore, a first liquid level sensor is provided at the bottom of the heater main body, a floating ball is provided on the first liquid level sensor, and a positioning seat is provided at the lower end of the first liquid level sensor for monitoring the fuel liquid level in the main oil chamber.

[0019] Furthermore, a second liquid level sensor is provided at the bottom of the oil suction main body for monitoring the fuel liquid level in the secondary oil chamber.

[0020] Furthermore, a primary filter and an oil-water separator are arranged in sequence on the first fuel supply pipe along the direction from the first fuel supply port to the fuel chamber.

[0021] Furthermore, the heating element is a spiral heating pipe.

[0022] Furthermore, a water inlet and a water outlet communicating with the circulation chamber are provided on the heater main body, and the water inlet and the water outlet are respectively communicated with the coolant chamber through a water inlet pipe and a water return pipe.

[0023] The present invention also provides an engine preheating and fuel circulation heating method applicable to extremely cold environments, including the following steps:

[0024] Step 1: At low temperatures, open the stop valves respectively provided on the water pipe and the circulation pipe to form a passage for the inlet and outlet of the coolant chamber; pump out the coolant through the water pump on the coolant heater, heat it in the heating chamber and then return it to the coolant chamber; meanwhile, suck oil from the secondary oil chamber through the oil pump, enter the heating tank main body through the fuel port to heat the heating chamber.

[0025] Step 2: After the engine cylinder block is heated, close the stop valves, the coolant heater and the oil pump; start the drive motor of the liquid fuel heater to drive the oil valve to rotate so as to cut off the connection with the main oil chamber; at this time, only supply oil through the oil suction element in the secondary oil chamber, suck low-grade diesel from the secondary oil suction pipe to the low-grade oil supply port, enter the fuel chamber through the second fuel supply pipe, the second fuel supply port, the first fuel supply port and the first fuel supply pipe to complete the engine start, and the low-grade diesel after start returns to the secondary oil chamber through the first return pipe, the first return port, the second return port and the second return pipe.

[0026] Step 3: After the engine starts, turn on the water pump, pump the heated coolant into the circulation chamber of the heater main body, enter the spiral heating pipe and transfer heat to the waxed diesel in the main oil chamber through heat exchange, and the waxed diesel melts and then returns to the fuel chamber to form a closed-loop circuit.

[0027] Step 4: After completing the low-temperature start of the engine and heating the diesel in the main oil chamber, cut off the fuel supply to the fuel suction element of the auxiliary oil chamber; after the fuel in the pipeline is consumed, start the drive motor again and open the connection between the fuel suction element of the main oil chamber and the main oil chamber; at this time, draw regular diesel through the main suction pipe, enter the fuel chamber of the engine block through the first fuel supply port and the first fuel supply pipe, and the regular diesel in the fuel chamber flows back to the main oil chamber through the first return pipe, the first return port, and the main return pipe; during this period, keep the water inlet and outlet passages outside the heater body in a through state, continuously heat, maintain a constant temperature, and stably supply fuel to the engine.

[0028] Compared with the prior art, the present invention shows significant advantages in the field of engine preheating and fuel circulation heating in extremely cold environments. By innovatively adopting the structural design of the main and auxiliary fuel tanks, the present invention only needs to store a small amount of low-grade diesel in the auxiliary fuel tank, accounting for 1 / 10 of the overall fuel tank capacity, while the main fuel tank stores regular diesel, accounting for 9 / 10 of the total fuel tank volume. This strategy greatly reduces the fuel cost while taking into account the starting performance and operating efficiency of the engine in low-temperature environments. In addition, the present invention uses the low-grade diesel in the auxiliary fuel tank for preheating, significantly shortening the preheating time of the engine under extremely cold conditions and improving the starting success rate. Its innovative fuel heater and coolant heater designs not only achieve more uniform and efficient heating but also effectively reduce energy consumption. To address the problem of diesel waxing at low temperatures, the present invention ensures that the waxed part of the regular diesel can quickly melt after the engine starts through a circulating heating method, avoiding the risk of pump suction difficulties and engine failures caused by diesel waxing. At the same time, the system enhances the flexibility and reliability of the system through the flexible switching of the oil valve and the drive motor, enabling the entire system to operate more stably and economically in extremely cold environments. In summary, the present invention shows significant advantages in terms of cost-effectiveness, engine starting performance, heating efficiency, avoiding the risk of diesel waxing, and system flexibility and reliability. Brief Description of the Drawings

[0029] Figure 1 is a schematic diagram of an engine preheating and fuel circulation heating system applicable to extremely cold environments in the present application;

[0030] Figure 2 is Figure 1 a partially enlarged schematic diagram of the middle fuel tank;

[0031] Figure 3 is a structural schematic diagram of the coolant heater in the present application;

[0032] Figure 4 is a structural schematic diagram of the fuel heater in the present application;

[0033] Figure 5 is a split structural schematic diagram of the fuel heater in the present application;

[0034] Figure 6 It is a schematic structural diagram of the oil suction element in the auxiliary oil chamber of this application;

[0035] Figure 7 It is a schematic top-down sectional view of the oil suction element in the auxiliary oil chamber of this application;

[0036] Figure 8 It is an installation schematic diagram of an engine preheating and fuel circulation heating system applicable to extremely cold environments in this application;

[0037] Figure 9 It is a principle block diagram when the main oil chamber oil suction element of this application is working;

[0038] Figure 10 It is a principle block diagram when the auxiliary oil chamber oil suction element of this application is working.

[0039] As shown in the figure: 1. Engine, 2. Coolant heater, 21. Heating tank main body, 211. Fuel port, 22. Water pump, 3. Fuel tank, 31. Main oil chamber, 32. Auxiliary oil chamber, 4. Fuel heater, 41. Heater main body, 411. Water inlet, 412. Water outlet, 413. Water inlet pipe, 414. Return pipe, 42. Oil valve, 421. Driving motor, 422. First oil return port, 423. First oil supply port, 424. Second oil return port, 425. Second oil supply port, 43. Heating element, 44. Main oil chamber oil suction element, 441. Main oil suction pipe, 442. Main oil return pipe, 443. First filter, 5. Auxiliary oil chamber oil suction element, 51. Oil suction main body, 511. Low-grade oil supply port, 512. Low-grade oil return port, 52. Auxiliary oil suction pipe, 53. Auxiliary oil return pipe, 54. Second filter, 55. Heater oil suction pipe, 56. Heater oil suction port, 6. Circulation water path, 61. Circulation pipe, 71. First oil supply pipe, 72. First oil return pipe, 73. Second oil supply pipe, 74. Second oil return pipe, 8. Fuel pipe, 81. Oil pump, 9. First liquid level sensor, 10. Second liquid level sensor, 11. Primary filter, 12. Oil-water separator. Detailed implementation manners

[0040] The present invention will be further described in detail below with reference to the accompanying drawings.

[0041] The specific implementation manners of the present invention will be further described below with reference to the accompanying drawings. Among them, the same components are denoted by the same reference numerals.

[0042] It should be noted that the terms "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the accompanying drawings, and the terms "inner" and "outer" respectively refer to the directions towards or away from the geometric center of a specific component.

[0043] In order to make the content of the present invention easier to be clearly understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0044] Refer to the attached Figure 1 - attached Figure 10 , the present invention provides an engine preheating and fuel circulation heating system applicable to extremely cold environments, including: an engine 1, the cylinder block of which is provided with a coolant chamber and a fuel chamber; a coolant heater 2, which is connected to the coolant chamber through a circulating waterway 6 and is used to heat the coolant in the coolant chamber; a fuel tank 3, which is divided into a main oil chamber 31 and a secondary oil chamber 32. Among them, the main oil chamber 31 stores regular diesel, accounting for 9 / 10 of the total volume of the fuel tank 3, while the secondary oil chamber 32 stores low-grade diesel, only accounting for 1 / 10 of the total volume of the fuel tank 3. Such a configuration significantly reduces the oil storage cost; a fuel heater 4, which is arranged inside the main oil chamber 31, includes a heater main body 41. Inside the heater main body 41, there is a circulating chamber that is circulated and connected to the coolant chamber and an oil valve 42 that is circulated and connected to the fuel chamber. Below the heater main body 41, there are a heating element 43 and a main oil chamber oil suction element 44. Among them, the heating element 43 is connected to the circulating chamber and is used to receive the coolant heated by the coolant chamber and heat the regular diesel in the main oil chamber 31. The main oil chamber oil suction element 44 is used to pump the regular diesel in the main oil chamber 31 into the oil valve 42; a secondary oil chamber oil suction element 5, which is arranged inside the secondary oil chamber 32, is connected to the oil valve 42 and pumps the low-grade diesel in the secondary oil chamber 32 into the oil valve 42. The oil valve 42 is connected to the fuel chamber, and the oil valve 42 switches the working modes of the secondary oil chamber oil suction element 5 and the main oil chamber oil suction element 44 through a driving motor 421 arranged outside it.

[0045] In order to heat the coolant more efficiently, the coolant heater 2 internally includes a heating tank main body 21, inside which there is a heating chamber. The heating tank main body 21 is equipped with a water pump 22. The water pump 22 pumps water from the coolant chamber through a water pipe, and after being heated by the heating chamber, it returns to the coolant chamber through a circulating pipe 61, forming a closed-loop heating system.

[0046] In one embodiment, in order to further improve the heating efficiency and fuel utilization rate of the system, a heater oil suction pipe 55 is added below the oil suction main body 51 in this embodiment. The oil suction pipe is connected to the fuel pipe 8 through a heater oil suction port 56, and directly transports the low-grade diesel to the fuel port 211 of the heating tank main body 21 for heating. In order to control the fuel supply amount, an oil pump 81 is arranged on the fuel pipe 8, and the fuel flow can be adjusted according to needs.

[0047] Meanwhile, to monitor the fuel levels in the main oil chamber 31 and the auxiliary oil chamber 32 in real time, in this embodiment, a first liquid level sensor 9 is provided below the oil suction element 44 of the main oil chamber, and a second liquid level sensor 10 is provided below the oil suction element 5 of the auxiliary oil chamber. Both the first liquid level sensor 9 and the second liquid level sensor 10 adopt a float type design and can float up and down as the fuel level rises and falls, thereby accurately reflecting the fuel quantity in the fuel tank 3. Through the real-time monitoring of the first liquid level sensor 9 and the second liquid level sensor 10, it is possible to ensure the timely replenishment of fuel and avoid the situation of fuel exhaustion;

[0048] The oil valve 42 is provided with a first oil return port 422, a first oil supply port 423, a second oil return port 424, and a second oil supply port 425 side by side. The first oil supply port 423 is connected to the fuel chamber through a first oil supply pipe 71, the first oil return port 422 is connected to the fuel chamber through a first oil return pipe 72, the second oil supply port 425 is connected to the low-grade oil supply port 511 through a second oil supply pipe 73, and the second oil return port 424 is connected to the low-grade oil return port 512 through a second oil return pipe 74. By switching the oil valve 42, it is possible to ensure the use of low-grade diesel during the engine preheating stage and switch to regular diesel during the normal operation stage, thereby meeting the requirements of the engine at different stages.

[0049] To further improve the heating efficiency and fuel utilization rate of the system, in this embodiment, a heater oil suction pipe 55 is added below the oil suction main body 51. The heater oil suction pipe 55 is connected to the fuel pipe 8 through a heater oil suction port 56, and directly transports the low-grade diesel to the fuel port 211 of the heating tank main body 21 for heating. To control the fuel supply amount, a fuel pump 81 is provided on the fuel pipe 8, and the fuel flow can be adjusted as needed.

[0050] To further improve the purity and safety of the fuel, in this embodiment, a primary filter 11 and an oil-water separator 12 are arranged in sequence on the first oil supply pipe 71 along the direction from the first oil supply port 423 to the fuel chamber. The primary filter 11 can further intercept and remove fine particles and impurities in the fuel, while the oil-water separator 12 can effectively separate the water in the fuel and prevent the water from damaging the engine. The addition of these two devices makes the fuel supplied to the engine 1 cleaner and safer.

[0051] In one embodiment, the heating element 43 is a spiral heating pipe. This design not only improves the heating efficiency but also makes the heating more uniform, avoiding the occurrence of local overheating or insufficient temperature. At the same time, the spiral heating pipe has a compact structure and small occupied space, which is beneficial to reducing the overall volume and weight of the system.

[0052] Furthermore, the heater body 41 is provided with a water inlet 411 and a water outlet 412 that communicate with the circulation chamber. The water inlet 411 and the water outlet 412 are respectively connected to the coolant chamber through a water inlet pipe 413 and a return pipe 414, forming a closed-loop circulation with the coolant chamber. Through the heat exchange between the coolant in the circulation chamber and the heating element 43, the heated heat can be transferred to the regular diesel in the main oil chamber 31, thereby realizing the functions of fuel preheating and anti-waxing. This design not only improves the heating efficiency of the fuel but also reduces energy consumption and costs.

[0053] The present invention also provides an engine preheating and fuel circulation heating method suitable for extremely cold environments, including the following steps:

[0054] Step 1: At low temperatures, open the stop valves provided on the water pipe and the circulation pipe 61 respectively to form a passage for the inlet and outlet of the coolant chamber; pump out the coolant through the water pump 22 on the coolant heater 2, heat it in the heating chamber and then return it to the coolant chamber; at the same time, suck oil from the secondary oil chamber 32 through the oil pump 81, and enter the heating tank body 21 through the fuel port 211 to heat the heating chamber.

[0055] Step 2: After the engine 1 cylinder block is heated, close the stop valve, the coolant heater 2 and the oil pump 81; start the drive motor 421 of the liquid fuel heater 4 to drive the oil valve 42 to rotate and cut off the connection with the main oil chamber 31; at this time, only supply oil through the secondary oil chamber oil suction element 5, and draw low-grade diesel from the secondary suction pipe 52 to the low-grade oil supply port 511, and enter the fuel chamber through the second supply pipe 73, the second supply port 425, the first supply port 423, and the first supply pipe 71 to complete the engine start. The low-grade diesel after starting flows back to the secondary oil chamber 32 through the first return pipe 72, the first return port 422, the second return port 424, and the second return pipe 74.

[0056] Step 3: After the engine 1 starts, open the water pump 22 to pump the heated coolant into the circulation chamber of the heater body 41, enter the spiral heating pipe and transfer heat to the waxed diesel in the main oil chamber 31 through heat exchange. After the waxed diesel melts, it flows back to the fuel chamber to form a closed-loop circuit.

[0057] Step 4: After completing the low-temperature start of the engine and heating the diesel in the main oil chamber, cut off the oil supply of the secondary oil chamber oil suction element 5; after the fuel in the pipeline is consumed, start the drive motor 421 again and open the connection between the main oil chamber oil suction element 44 and the main oil chamber 31; at this time, suck regular diesel through the main suction pipe 441, enter the engine cylinder block fuel chamber through the first supply port 423 and the first supply pipe 71, and the regular diesel in the fuel chamber flows back to the main oil chamber 31 through the first return pipe 72, the first return port 422, and the main return pipe 442; during this period, keep the water inlet 411 and the water outlet 412 outside the heater body 41 in a passage state, continuously heat, keep the temperature constant, and stably supply oil to the engine.

[0058] The present invention and its embodiments have been described above. Such description is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. In general, if those of ordinary skill in the art are inspired by it and, without departing from the gist of the present invention, creatively design structural modes and embodiments similar to the technical solution, they shall fall within the protection scope of the present invention.

Claims

1. An engine preheating and fuel circulation heating system suitable for extremely cold environments, characterized in that: include: An engine (1) has a cylinder body provided with a coolant chamber and a fuel chamber; A coolant heater (2), the coolant heater (2) being connected to the coolant chamber via a circulating water circuit (6) and used for heating the coolant in the coolant chamber; The oil tank (3) is divided into a main oil chamber (31) and an auxiliary oil chamber (32), wherein the auxiliary oil chamber (32) is used to store low-grade diesel, and the main oil chamber (31) is used to store conventional diesel; A fuel heater (4) is arranged inside the main oil chamber (31), comprising a heater body (41), wherein a circulation chamber circulated in communication with the cooling liquid chamber and an oil valve (42) circulated in communication with the fuel chamber are arranged inside the heater body (41), and a heating element (43) and a main oil chamber oil suction element (44) are arranged below the heater body (41), wherein the heating element (43) is connected to the circulation chamber and is used to receive the cooling liquid heated from the cooling liquid chamber and heat the conventional diesel in the main oil chamber (31), and the main oil chamber oil suction element (44) is used to draw the conventional diesel in the main oil chamber (31) into the oil valve (42); The auxiliary oil chamber oil suction element (5) is arranged inside the auxiliary oil chamber (32), is connected to the oil valve (42) and draws the low-grade diesel in the auxiliary oil chamber (32) into the oil valve (42), the oil valve (42) is connected to the fuel chamber and the oil valve (42) switches the working mode of the auxiliary oil chamber oil suction element (5) and the main oil chamber oil suction element (44) through a driving motor (421) arranged outside the oil valve (42).

2. The engine preheating and fuel circulation heating system suitable for extremely cold environments according to claim 1, characterized in that: The coolant heater (2) comprises a heating tank body (21), a heating chamber is provided in the heating tank body (21), a water pump (22) is also provided on the heating tank body (21), a water suction port of the water pump (22) is connected to the coolant chamber via a water pipe, a water outlet of the water pump is connected to the heating chamber, and a hot water outlet on the heating tank body (21) flows back to the coolant chamber via a circulation pipe (61).

3. The engine preheating and fuel circulation heating system suitable for extremely cold environments according to claim 1, characterized in that: The main oil chamber oil suction element (44) comprises a main oil suction pipe (441), a main oil return pipe (442), and a first filter (443) arranged below the main oil suction pipe (441) and the main oil return pipe (442); The auxiliary oil chamber oil suction element (5) comprises an oil suction body (51), a low-standard oil supply port (511) and a low-standard oil return port (512) are arranged above the oil suction body (51), an auxiliary oil suction pipe (52) and an auxiliary oil return pipe (53) are arranged below the oil suction body (51), and a second filter (54) is arranged below the auxiliary oil suction pipe (52) and the auxiliary oil return pipe (53); The oil valve (42) is provided with a first oil return port (422), a first oil supply port (423), a second oil return port (424) and a second oil supply port (425) in parallel; the first oil supply port (423) is connected to the fuel chamber via a first oil supply pipe (71); the first oil return port (422) is connected to the fuel chamber via a first oil return pipe (72); the second oil supply port (425) is connected to the low-standard oil supply port (511) via a second oil supply pipe (73); and the second oil return port (424) is connected to the low-standard oil return port (512) via a second oil return pipe (74).

4. The engine preheating and fuel circulation heating system suitable for extremely cold environments according to claim 3, characterized in that: A heater oil suction pipe (55) is also provided below the oil suction body (51), and a heater oil suction port (56) connected to the heater oil suction pipe (55) is provided above the oil suction body (51). The heater oil suction port (56) is connected to the fuel port (211) on the heating tank body (21) through a fuel oil pipe (8), and an oil pump (81) is provided on the fuel oil pipe (8).

5. The engine preheating and fuel circulation heating system suitable for extremely cold environments according to claim 3, characterized in that: A first liquid level sensor (9) is also provided at the bottom of the heater body (41), a float is provided on the first liquid level sensor (9), and a positioning seat is provided at the lower end of the first liquid level sensor (9) for monitoring the fuel liquid level in the main oil chamber (31).

6. The engine preheating and fuel circulation heating system suitable for extremely cold environments according to claim 3, characterized in that: A second liquid level sensor (10) is also provided at the bottom of the oil suction body (51) for monitoring the fuel liquid level in the auxiliary oil chamber (32).

7. The engine preheating and fuel circulation heating system suitable for extremely cold environments according to claim 3, characterized in that: A primary filter (11) and an oil-water separator (12) are arranged in sequence on the first oil supply pipe (71) along the direction from the first oil supply port (423) to the fuel chamber.

8. The engine preheating and fuel circulation heating system suitable for extremely cold environments according to claim 1, characterized in that: The heating element (43) is a spiral heating tube.

9. The engine preheating and fuel circulation heating system suitable for extremely cold environments according to claim 1, characterized in that: The heater body (41) is provided with a water inlet (411) and a water outlet (412) which are in communication with the circulation chamber. The water inlet (411) and the water outlet (412) are in communication with the cooling liquid chamber via a water inlet pipe (413) and a water return pipe (414) respectively.

10. An engine preheating and fuel circulation heating method suitable for extremely cold environments, characterized in that: The following steps are involved: Step 1: When the temperature is low, the stop valves respectively arranged on the water pipe and the circulation pipe (61) are opened to form a passage at the water inlet and outlet of the cooling liquid chamber; the cooling liquid is pumped out by the water pump (22) on the cooling liquid heater (2), and the cooling liquid is heated in the heating chamber and then flows back to the cooling liquid chamber; at the same time, the oil is sucked from the auxiliary oil chamber (32) by the oil pump (81), and enters the heating tank body (21) through the fuel port (211) to heat the heating chamber; Step 2: After the cylinder of the engine (1) is heated, the stop valve, the coolant heater (2) and the oil pump (81) are closed; the driving motor (421) of the liquid fuel heater (4) is started to drive the oil valve (42) to rotate so as to cut off the connection with the main oil chamber (31); at this time, oil is supplied only through the auxiliary oil chamber oil suction element (5), and low-grade diesel is pumped from the auxiliary oil suction pipe (52) to the low-grade oil supply port (511), and enters the fuel chamber through the second oil supply pipe (73), the second oil supply port (425), the first oil supply port (423), and the first oil supply pipe (71), completing the engine start-up. After the start-up, the low-grade diesel flows back to the auxiliary oil chamber (32) through the first oil return pipe (72), the first oil return port (422), the second oil return port (424), and the second oil return pipe (74); Step 3: After the engine (1) is started, the water pump (22) is turned on to pump the heated coolant into the circulation chamber of the heater body (41), and then into the spiral heating tube to be transferred to the waxed diesel in the main oil chamber (31) through heat exchange. The waxed diesel melts and flows back to the fuel chamber, forming a closed loop. Step 4: After the low-temperature start-up of the engine and the heating of the diesel in the main oil chamber are completed, the oil supply of the auxiliary oil chamber oil suction element (5) is cut off; after the fuel in the pipeline is consumed, the drive motor (421) is started again, and the connection between the main oil chamber oil suction element (44) and the main oil chamber (31) is opened; at this time, conventional diesel is sucked through the main oil suction pipe (441) and enters the fuel chamber through the first oil supply port (423) and the first oil supply pipe (71), and the conventional diesel in the fuel chamber flows back to the main oil chamber (31) through the first oil return pipe (72), the first oil return port (422), and the main oil return pipe (442); during this period, the water inlet (411) and the water outlet (412) outside the heater body (41) are kept in the passage state, heating is continued, a constant temperature is maintained, and the engine (1) is stably supplied with oil.

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