CN114508450A

CN114508450A - Fuel supply system and fuel supply method thereof

Info

Publication number: CN114508450A
Application number: CN202210140912.3A
Authority: CN
Inventors: 郭平; 尹燕升; 张驰; 朱宏志; 张贵华
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: 2022-05-17

Abstract

The invention relates to the technical field of vehicles, and particularly discloses a fuel supply system and a fuel supply method thereof.

Description

Fuel supply system and fuel supply method thereof

Technical Field

The invention relates to the technical field of vehicles, in particular to a fuel supply system and a fuel supply method thereof.

Background

At normal temperature, 0# diesel oil is used in common diesel vehicles. In extremely cold areas, the freezing point of 0# diesel oil is 4 ℃ due to too low temperature, so the 0# diesel oil can generate wax precipitation phenomenon, thereby blocking an oil way in a fuel oil supply system of an engine and influencing the normal work of the engine.

In order to solve the above problems, the following solutions are adopted in the prior art: the fuel tank is divided into a part for storing the-35 # diesel fuel, the engine is started in advance by using the-35 # diesel fuel, and then the 0# diesel fuel is heated by using the engine coolant, so that the engine can use the 0# diesel fuel and normally work. However, the engine coolant is used for heating the 0# diesel oil, so that the fuel oil of two marks and the coolant and the fuel oil are mixed easily; and when fuel switches, the operation is complicated; two oil tanks need to be configured, and the fuel oil filling process is quite complicated; and because of adopting two fuel tanks, lead to the pipeline complicated, assembly maintenance is all inconvenient.

In view of the above, the earlier patent with application number CN201810864184.4 provides a positive pressure oil supply system for a cold area of a diesel vehicle and an oil supply method thereof, in which 0# diesel oil can be used to supply oil to an engine in the positive pressure oil supply system for a cold area of a diesel vehicle, specifically, an electric pump, a one-way valve and a fuel electromagnetic switch valve are arranged in an oil tank, the electric pump supplies oil to an oil inlet pipe of the engine, the fuel electromagnetic switch valve controls the connection or disconnection of an oil inlet pipe and an oil return pipe of the engine, when the ambient temperature is below zero, the fuel electromagnetic switch valve is opened, the electric pump drives fuel to circulate between the oil inlet pipe, the fuel electromagnetic switch valve, the oil return pipe and the oil tank, so as to melt the fuel, and after the fuel is melted, the fuel electromagnetic switch valve is closed, and the electric pump supplies fuel to the engine. Although the oil supply system can well solve the problems, the positive pressure oil supply system only adopts one oil tank to supply fuel oil to the engine, and when the fuel oil in the oil tank is insufficient and the fuel oil cannot be supplied nearby, the vehicle is easily broken down.

Disclosure of Invention

The invention aims to: the fuel supply system and the fuel supply method thereof are provided to solve the problem that when fuel is supplied to an engine through a positive pressure fuel supply system in the prior art, fuel is supplied through a fuel tank, and when the fuel in the fuel tank is insufficient and the fuel cannot be supplied nearby, the vehicle is easily anchored.

The invention provides a fuel supply system, which comprises a first fuel tank, a first suction pump and a first one-way valve, wherein the first suction pump and the first one-way valve are arranged in the first fuel tank, the first suction pump is used for sucking fuel from the first fuel tank and supplying the fuel to an engine, the first one-way valve is arranged between the first fuel tank and an output port of the first suction pump, and the first one-way valve is configured to only allow the fuel in the first fuel tank to be conveyed to the output port of the first suction pump through the first one-way valve, and the fuel supply system further comprises:

a second fuel tank for storing fuel of the same grade as in the first fuel tank;

the fuel oil pump comprises a second fuel oil tank, a second fuel oil pump and a fuel oil supplementing pipe, wherein an input port of the second fuel oil pump absorbs fuel oil from the second fuel oil tank, an output port of the second fuel oil pump is connected with the fuel oil supplementing pipe, and the fuel oil supplementing pipe stretches into the first fuel oil tank.

As a preferable mode of the fuel supply system, the fuel supply system further includes a second check valve, an input port of the second check valve communicates with the second fuel tank, an output port of the second check valve communicates with an output port of the first suction pump, and the second check valve is configured to allow only fuel to flow from the second fuel tank to the output port of the second suction pump through the second check valve.

As a preferable technical scheme of the fuel supply system, the length of a connecting pipeline between the input port of the second one-way valve and the second fuel tank is 0 mm-100 mm; and/or the presence of a gas in the gas,

the length of the connecting pipeline between the output port of the second one-way valve and the output port of the second oil suction pump is 0-200 mm.

As a preferable technical scheme of the fuel supply system, a filter screen is arranged on a connecting pipeline between an input port of the second one-way valve and the second fuel tank.

As a preferred technical solution for fuel supply systemThe flow area of a connecting pipeline between the input port of the second one-way valve and the second fuel tank and the flow area of a connecting pipeline between the output port of the second one-way valve and the output port of the second oil suction pump are both 50mm²-180mm²。

As a preferable technical solution of the fuel supply system, the density of the valve ball of the second check valve is smaller than the density of the liquid fuel.

As a preferable technical solution of the fuel supply system, the second oil suction pump and the second check valve are both disposed in the second fuel tank and located at the bottom of the second fuel tank; alternatively, the first and second electrodes may be,

the second oil suction pump and the second one-way valve are both arranged in the second fuel tank and positioned at the top of the second fuel tank, an input port of the second oil suction pump is connected with the first extension pipe, an input port of the second one-way valve is connected with the second extension pipe, and the first extension pipe and the second extension pipe both extend to the bottom of the second fuel tank.

As a preferable technical solution of the fuel supply system, the fuel supply system further includes a first filter screen and a first electric heating element which are arranged in the first fuel tank; the first filter screen is positioned below an input port of the first oil suction pump, and the first electric heating element is positioned below the first filter screen; and/or the presence of a gas in the gas,

the fuel supply system also comprises a second filter screen and a second electric heating element which are arranged in the second fuel tank; the second filter screen is positioned below an input port of the second oil suction pump, and the second electric heating element is positioned below the second filter screen.

The present invention also provides an oil supply method of the fuel supply system in any one of the above aspects, including:

and when the fuel liquid level in the second fuel tank is higher than the fuel liquid level in the first fuel tank, and the height difference between the fuel liquid level in the second fuel tank and the fuel liquid level in the first fuel tank does not exceed a set value, the second oil suction pump is started.

The present invention further provides a fuel supply method for a fuel supply system according to any one of the above aspects, wherein the fuel supply system further comprises a second check valve, an input port of the second check valve is communicated with the second fuel tank, an output port of the second check valve is communicated with an output port of the first oil suction pump, and the second check valve is configured to only allow fuel to flow from the second fuel tank to the output port of the second oil suction pump through the second check valve;

the fuel supply method of the fuel supply system further includes:

when the fuel level in the second fuel tank is higher than the fuel level in the first fuel tank, and the height difference between the fuel level in the second fuel tank and the fuel level in the first fuel tank is larger than a set value, the second suction pump is closed;

when the height difference between the fuel liquid level in the second fuel tank and the fuel liquid level in the first fuel tank is larger than a set value, the fuel in the second fuel tank can flow into the first fuel tank through the second one-way valve and the fuel replenishing oil pipe.

The invention has the beneficial effects that:

the invention provides a fuel supply system and a fuel supply method thereof, wherein the fuel supply system comprises a first fuel tank and a second fuel tank which store fuel with the same label, a first suction pump which is used for supplying the fuel in the first fuel tank to an engine, a first one-way valve which is connected with the output ports of the first fuel tank and the first suction pump, and a second suction pump which is used for supplying the fuel in the second fuel tank to the first fuel tank, so that the fuel is directly supplied to the engine through the first fuel tank, the second fuel tank stores standby fuel, and when the fuel in the first fuel tank is insufficient, the fuel in the second fuel tank is supplemented to the first fuel tank, thereby preventing the vehicle from being anchored due to insufficient fuel in the running process.

Drawings

FIG. 1 is a first schematic structural diagram of a fuel supply system according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of an oil supply assembly according to an embodiment of the present invention;

FIG. 3 is a schematic view showing a part of the structure of an oil suction valve in the embodiment of the present invention;

FIG. 4 is a second schematic view of a part of the structure of the oil suction valve in the embodiment of the present invention;

figure 5 is a front view of an oil suction valve in an embodiment of the invention;

fig. 6 is a sectional view showing a partial structure of an oil suction valve in the embodiment of the present invention;

fig. 7 is a top view of an oil suction valve in an embodiment of the present invention;

fig. 8 is a third partial structural view of an oil suction valve in the embodiment of the present invention;

fig. 9 is a fourth partial structural schematic diagram of an oil suction valve in the embodiment of the invention;

FIG. 10 is a second schematic structural view of a fuel supply system according to an embodiment of the present invention;

FIG. 11 is a first schematic structural view of a second fuel tank and its internal components of the fuel supply system of the embodiment of the present invention;

fig. 12 is a second schematic structural diagram of a second fuel tank and internal components of the fuel supply system in the embodiment of the invention.

In the figure:

1. an engine;

2. a first fuel tank;

3. an oil suction valve; 31. a first oil suction pump; 32. a first control valve; 33. a first electric heating element; 34. a first filter screen; 35. a first check valve; 36. a first connecting pipe; 37. a second connecting pipe; 38. a float tube; 39. an upper base; 40. a lower base; 41. a temperature sensor; 42. a circuit board; 43. a box body; 431. opening the mouth;

51. an oil supply line; 52. an oil return line; 521. an oil return hole;

6. an oil supply assembly; 61. an oil transfer pump; 62. a bypass line; 63. a bypass check valve;

71. a first filter; 72. a second filter;

81. a second fuel tank; 82. a second oil suction pump; 83. an oil supplementing pipe; 84. a second one-way valve; 85. a second electric heating element; 86. a second filter screen; 87. a first extension pipe.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Where the terms "first position" and "second position" are two different positions, and where a first feature is "over", "above" and "on" a second feature, it is intended that the first feature is directly over and obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the prior art, in order to supply oil to an engine only by 0# diesel, a positive-pressure oil supply system for a cold region of a diesel vehicle is provided, wherein an electric pump, a one-way valve and a fuel electromagnetic switch valve are arranged in an oil tank, the electric pump supplies oil to an oil inlet pipe of the engine, the fuel electromagnetic switch valve controls the connection or disconnection of the oil inlet pipe and the oil return pipe of the engine, when the ambient temperature is below zero, the fuel electromagnetic switch valve is opened, the electric pump drives the fuel to circulate among the oil inlet pipe, the fuel electromagnetic switch valve, the oil return pipe and the oil tank, so that the fuel is melted, and after the fuel is melted, the fuel electromagnetic switch valve is closed, and the fuel is supplied to the engine through the electric pump. However, the fuel supply system supplies fuel to the engine only through the electric pump, the electric pump needs to be operated under a high load continuously to meet the high-pressure requirement of the engine on the fuel, the electric pump is prone to failure, and potential safety hazards exist when the electric pump fails.

In this regard, the present embodiment provides a fuel supply system that is also capable of supplying the engine with only 0# diesel, while also solving the above-described problems.

As shown in fig. 1, the fuel supply system includes an engine 1, a first fuel tank 2, a suction valve 3, a fuel supply line 51, a return line 52, and a fuel supply package 6. The oil suction valve 3 and the oil supply assembly 6 can pump fuel oil to the engine 1, the fuel oil in the first fuel tank 2 can be sequentially supplied to the engine 1 through the oil suction valve 3, the oil supply pipeline 51 and the oil supply assembly 6 under the pumping action of the oil suction valve 3 and/or the oil supply assembly 6, and the fuel oil which does not participate in combustion in the engine 1 can flow back to the first fuel tank 2 through the oil return pipeline 52.

Specifically, the engine 1 in the present embodiment is specifically a diesel engine 1, and the engine 1 is applicable to business vehicles and various construction vehicles. The first fuel tank 2 is used for storing 0# diesel. The oil suction valve 3 comprises a first oil suction pump 31 and a first control valve 32, the first oil suction pump 31 is an electric pump, an input port of the first oil suction pump 31 is positioned in the first fuel tank 2 and can suck fuel oil from the first fuel tank 2, an output port of the first oil suction pump 31 is communicated with an oil supply pipeline 51, the oil supply pipeline 51 is connected with an oil inlet of the engine 1, and an oil return pipeline 52 is connected with an oil return port of the engine 1 and the first fuel oil tank.

In the present embodiment, the first control valve 32 can control the connection or disconnection of the oil supply line 51 and the oil return line 52. When the first control valve 32 controls the oil supply pipeline 51 to be communicated with the oil return pipeline 52, fuel can circulate among the first fuel tank 2, the first oil suction pump 31, the oil supply pipeline 51, the first control valve 32, the oil return pipeline 52 and the first fuel tank 2, and the fuel near the first oil suction pump 31 can be heated by the fuel circulation and depending on the first oil suction pump 31 to do work, so that solid fuel is gradually melted, and the fuel heating device can be suitable for the working condition that the fuel in the first fuel tank 2 is solidified due to low temperature. When the first control valve 32 controls the fuel supply line 51 and the fuel return line 52 to be disconnected, the first suction pump 31 can drive the fuel to be supplied to the engine 1 through the fuel supply line 51 and the fuel supply unit 6, and is suitable for the condition that the fuel in the first fuel tank 2 is at least partially in a liquid state and is used for the starting condition of the engine 1. The first control valve 32 may be an electric control valve or a mechanical valve.

As shown in fig. 2, in the present embodiment, the oil supply unit 6 includes an oil feed pump 61 and a bypass line 62. The oil delivery pump 61 is connected in series with the oil supply pipeline 51, one end of the bypass pipeline 62 is communicated with the input end of the oil delivery pump 61, the other end of the bypass pipeline 62 is communicated with the output end of the oil delivery pump 61, and the engine 1 is in transmission connection with the oil delivery pump 61. When the engine 1 is started, the engine 1 drives the oil delivery pump 61 to work; the oil feed pump 61 does not operate before the engine 1 is started, and it is arranged so that the load of the first oil suction pump 31 can be reduced after the engine 1 is started, and the oil feed pump 61 can be driven without wasting electric energy. Specifically, according to the fuel supply assembly 6 provided by the present embodiment, after the engine 1 is started, the fuel delivery pump 61 is opened, the bypass line 62 is disconnected, and the fuel in the fuel supply line 51 is pressurized by the fuel delivery pump 61 to be delivered to the engine 1, so that the requirement for high pressure oil during the operation of the engine 1 can be met, the workload of the first suction pump 31 can be reduced, the first suction pump 31 is prevented from being continuously operated under high pressure, the service life of the first suction pump 31 is prolonged, and the probability of failure of the first suction pump 31 is reduced. Before the engine 1 is started, the fuel delivery pump 61 is closed, the bypass pipeline 62 is communicated, at the moment, the fuel delivery pump 61 has high resistance, the fuel in the fuel supply pipeline 51 is blocked by the fuel delivery pump 61, in order to ensure the normal fuel supply of the engine 1, the bypass pipeline 62 is communicated, and the fuel in the first fuel tank 2 is pumped to the engine 1 under the action of the first fuel suction pump 31, so that the engine 1 can be started normally.

It should be noted that the oil pumping assembly can also be independently applied to other fuel supply systems. For example, other fuel supply systems may include a fuel tank, an electric pump disposed in the fuel tank, a control valve, and a supply line 51, the supply line 51 having one end connected to the control valve and the other end connected to the input of the fuel pump 61, the control valve controlling the supply line 51 to be in communication with the electric pump and the fuel tank.

Optionally, a second control valve is disposed on the bypass line 62, and the bypass line 62 is controlled to be connected or disconnected by the second control valve. In the present embodiment, the second control valve is embodied as a bypass check valve 63, and the bypass check valve 63 is configured to allow only the fuel in the supply line 51 to flow from the input port of the fuel pump 61 to the output port of the fuel pump 61 through the bypass line 62. It will be appreciated that, after the engine 1 is started, the feed pump 61 is turned on, and the oil pressure at the feed inlet of the feed pump 61 is lower than the oil pressure at the outlet of the feed pump 61, so that the oil pressure at the inlet of the bypass check valve 63 is lower than the oil pressure at the outlet of the bypass check valve 63, keeping the bypass check valve 63 closed. Before the engine 1 is started, fuel is pumped only by the first suction pump 31, and the oil pressure at the inlet of the bypass check valve 63 is higher than the oil pressure at the outlet of the bypass check valve 63, so that the bypass check valve 63 can be kept open. As an alternative thereto, the bypass non-return valve 63 may instead be an electrically controlled valve.

Optionally, the bypass check valve 63 and the oil delivery pump 61 are integrally arranged, so that the assembly efficiency of the oil supply assembly 6 can be improved, and the bypass check valve 63 and the oil delivery pump 61 can also be separately arranged, so that the maintenance cost after any one part is damaged can be reduced.

Alternatively, the length of the portion of the bypass line 62 between the input port of the bypass check valve 63 and the input port of the feed pump 61 is 0mm to 200 mm. Illustratively, the specific size of the length of the portion of the bypass line 62 between the input port of the bypass check valve 63 and the input port of the feed pump 61 is 0mm, 50mm, 100mm, 150mm, or 200 mm. Further, the length of the portion of the bypass line 62 between the output port of the bypass check valve 63 and the output port of the oil feed pump 61 is 0mm to 200 mm. Illustratively, the specific size of the length of the portion of the bypass line 62 between the output of the bypass check valve 63 and the output of the feed pump 61 is 0mm, 50mm, 100mm, 150mm, or 200 mm. Optionally, the flow areas of the bypass line 62 and the bypass check valve 63 are both 50mm²～180mm²In the meantime. For example, the flow areas of the bypass line 62 and the bypass check valve 63 may be 50mm²、60mm²、70mm²、80mm²、90mm²、100mm²、110mm²、120mm²、130mm²、140mm²、150mm²、160mm²、170mm²Or 180mm². The arrangement ensures that the line pressure loss caused by the bypass line 62 is not too high, and particularly, the bypass line 62 can meet the transportation of a small amount of solid fuel under the pumping of the first suction oil pump 31 before the engine 1 is started.

Optionally, the ball of the bypass check valve 63 has a density less than the density of the liquid fuel. Specifically, the density of the valve ball of the bypass check valve 63 is 0.5g/ml to 0.8 g/ml. Illustratively, the ball of the bypass check valve 63 has a density of 0.5g/ml, 0.55g/ml, 0.6g/ml, 0.65g/ml, 0.7g/ml, 0.75g/ml, or 0.8 g/ml. So set up, the valve ball of bypass check valve 63 can float in liquid fuel, is difficult to take place the jamming with bypass check valve 63's casing, guarantees bypass check valve 63's stability.

Optionally, the fuel supply system further comprises a first filter 71 connected in series to the supply line 51, the first filter 71 being adapted to filter the fuel delivered by the supply line 51 to the fuel delivery pump 61. Specifically, the first filter 71 is disposed between the fuel delivery pump 61 and the first suction pump 31, and impurities are prevented from entering the engine 1 with the fuel under the filtering of the first filter 71, so as to ensure the normal operation of the engine 1. Preferably, the first filter 71 is integrated with an electric heating element, which heats the fuel flowing through to meet the use requirements of a low temperature environment.

Optionally, the fuel supply system further includes a second filter 72 connected in series to the fuel supply line 51, the second filter 72 being located between the fuel feed pump 61 and the engine 1, and the first filter 71 having a filtering accuracy lower than that of the second filter 72. Through the cooperation of the second filter 72 and the first filter 71, the impurities in the fuel can be filtered in a grading way, so that the filtering load of the first filter 71 can be reduced, and meanwhile, the filter element replacement period of the first filter 71 can be prolonged. In this embodiment, the first filter 71 may be a coarse filter, and the second filter 72 may be a fine filter. Preferably, the second filter 72 incorporates an electrical heating element to heat the fuel flowing therethrough to accommodate the demands of the low temperature environment.

As shown in fig. 3, the oil suction valve 3 optionally further includes a first strainer 34 and a first heating member, the first strainer 34 being disposed below the input port of the first oil suction pump 31, the first heating member being used to heat the fuel oil. Under the action of the first filter 34, the large solid fuel can be cut into a plurality of small pieces by the first filter 34, so that the first suction pump 31 can pump the fuel, and impurities in the fuel can be filtered by the first filter. The solid fuel at low temperature can be heated by the first heater, so that the volume of the solid fuel is reduced or the solid fuel becomes liquid, and particularly, the fuel at the first filter screen is heated, so that the first filter screen can be prevented from being covered by the solid fuel, and the first oil suction pump 31 can normally suck oil.

Optionally, the filtering precision of the first filter screen 34 is 50um to 500 um. Illustratively, the first screen 34 may have a filtering accuracy of 50um, 100um, 150um, 200um, 250um, 300um, 350um, 400um, 450um, or 500 um.

It has been found through experiments that when the distance between the input port of the first suction oil pump 31 and the bottom surface of the first fuel tank 2 is too large, a part of the fuel in the first fuel tank 2 is likely to be not effectively used, when the distance between the input port of the first suction oil pump 31 and the bottom surface of the first fuel tank 2 is too small, particularly after the fuel is solidified, the fuel around the first suction oil pump 31 is difficult to be delivered to the input port of the first suction oil pump 31 due to the solidification of the fuel, and the solid fuel can be sucked to the input port of the first suction oil pump 31 only when the size of the solid fuel is smaller than the distance between the input port of the first suction oil pump 31 and the bottom surface of the first fuel tank 2.

In contrast, in the suction valve 3 of the present embodiment, the distance between the input port of the first suction pump 31 and the bottom surface of the first fuel tank 2 is 15mm to 100 mm. By the arrangement, effective utilization of fuel in the first fuel tank 2 is not influenced, and effective delivery of the solidified fuel to the input port of the first suction pump 31 can be guaranteed. For example, the distance between the input port of the first suction oil pump 31 and the bottom surface of the first fuel tank 2 may be 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, or 100 mm.

It should be noted that the first heating element and the first filter 34 can be provided separately, but this also directly results in a cumbersome installation process of the oil suction valve 3. Therefore, as an alternative scheme, as shown in fig. 4, the first electric heating element 33 and the first filter screen 34 can be integrally arranged, which not only can improve the installation efficiency of the oil suction valve 3, but also the first filter screen 34 itself will have a heating function, which can further improve the heating effect on the solid fuel, and prevent the solid fuel from covering the first filter screen 34.

Alternatively, the first oil suction pump 31, the first strainer 34, and the first heating member are integrally provided. With this arrangement, the assembling efficiency of the oil suction valve 3 can be further improved.

Optionally, the first heating member is spaced from the first screen 34 by a distance of 3mm to 30 mm. The first heating member is a first electric heating member 33. The heating power of the first electric heating member 33 is 50W-300W. The first electric heating element 33 is operated at 24V dc. It should be noted that, because the solid fuel blocks on the first filter screen 34 to generate a large oil resistance, and the vacuum suction force generated by the first oil suction pump 31 cannot overcome the resistance, it is necessary to heat the first filter screen 34 by the first electric heating element 33 to fuse the solid fuel at the first filter screen 34, and therefore, the distance between the first electric heating element and the first filter screen 34 and the heating power of the first electric heating element 33 are selected to ensure that the first electric heating element 33 can melt the solid fuel on the surface of the first filter screen 34. Illustratively, the first heating member may be spaced from the first screen 34 by a distance of 3mm, 5mm, 7mm, 9mm, 11mm, 13mm, 15mm, 17mm, 19mm, 21mm, 23mm, 25mm, 27mm, 29mm, or 30 mm; the heating power of the first electric heating member 33 may be 50W, 100W, 150W, 200W, 250W, or 300W.

Optionally, as shown in fig. 3 to 4, the suction valve 3 further includes a first check valve 35, and the first check valve 35 is configured to allow the fuel in the first fuel tank 2 to pass through the first check valve 35 and be delivered to the output port of the first suction pump 31. When the engine 1 is running, the vacuum pumping force generated by the fuel delivery pump 61 can deliver the fuel from the first fuel tank 2 to the fuel supply pipeline 51 through the first check valve 35, at this time, the first fuel suction pump 31 can be closed, and the normal fuel supply of the engine 1 can be ensured by the operation of the fuel delivery pump 61. It should be noted that when the first suction pump 31 is turned on, the pressure at the output port of the first check valve 35 is higher than the pressure at the input port of the first check valve 35, and the ball of the first check valve 35 blocks the input port of the first check valve 35, so as to prevent the fuel from flowing back to the first fuel tank 2 through the first check valve 35.

Wherein the length of the connecting pipeline between the input port of the first check valve 35 and the first fuel tank 2 is 0 mm-100 mm. The length of the connecting pipeline between the output port of the first check valve 35 and the output port of the first oil suction pump 31 is 0mm to 200 mm. The flow area of the connecting line between the inlet of the first check valve 35 and the first fuel tank 2 and the flow area of the connecting line between the outlet of the first check valve 35 and the outlet of the first suction pump 31 are both 50mm²～180mm². When the engine 1 is running, the first check valve 35 of the fuel in the first fuel tank 2 is sucked into the fuel supply pipeline 51 by the vacuum pumping force generated by the fuel delivery pump 61, the vacuum suction force distributed to the pipeline where the first check valve 35 is located is small, therefore, the total length of the pipeline is short, the flow area is large enough, so that the resistance generated by the solid fuel can be smaller than the vacuum suction force, and the solid diesel is ensured to be located at the first check valve 35Flows in the pipeline. By way of example, the length of the connecting line between the inlet of the first non-return valve 35 and the first fuel tank 2 can be 0mm, 50mm or 100 mm; the length of the connecting pipeline between the output port of the first check valve 35 and the output port of the first oil suction pump 31 may be 0mm, 50mm, 100mm, 150mm or 200 mm; the flow area of the connecting line between the input of the first check valve 35 and the first fuel tank 2 and the flow area of the connecting line between the output of the first check valve 35 and the output of the first suction pump 31 may be 50mm²、60mm²、70mm²、80mm²、90mm²、100mm²、110mm²、120mm²、130mm²、140mm²、150mm²、160mm²、170mm²Or 180mm²。

Optionally, the ball of the first one-way valve 35 has a density less than the density of the liquid fuel. Specifically, the density of the valve ball of the first check valve 35 is 0.5g/ml to 0.8 g/ml. Illustratively, the ball of the first one-way valve 35 may have a density of 0.5g/ml, 0.55g/ml, 0.6g/ml, 0.65g/ml, 0.7g/ml, 0.75g/ml, or 0.8 g/ml. So set up, first check valve 35's valve ball can float in liquid fuel, is difficult to take place the jamming with first check valve 35's casing, guarantees first check valve 35's stability.

Optionally, the connection between the inlet of the first non return valve 35 and the first fuel tank 2 is provided with a filter screen. By arranging the filter screen, impurities can be prevented from entering the first check valve 35, and the first check valve 35 is prevented from being blocked.

Alternatively, the input port of the first suction pump 31 is in direct communication with the first fuel tank 2. No pipeline is arranged between the first oil suction pump 31 and the first fuel tank 2, so that oil resistance can be effectively reduced.

As shown in fig. 5 and 6, the oil suction valve 3 optionally further comprises a first connecting pipe 36 and a second connecting pipe 37. The first connecting pipe 36 is a part of the oil supply pipeline 51, the second connecting pipe 37 is a part of the oil return pipeline 52, specifically, the first connecting pipe 36 is connected to the output port of the first oil suction pump 31, the second connecting pipe 37 is connected to the first fuel tank 2, and the first control valve 32 can control the first connecting pipe 36 to be connected with or disconnected from the second connecting pipe 37. The first connecting pipe 36 and the second connecting pipe 37 are made of metal material. So configured, the first suction oil pump 31 may support the first control valve 32 through the first connection pipe 36 and the second connection pipe 37.

Alternatively, the suction valve 3 further includes an upper base 39 and a lower base 40, the first suction pump 31 is mounted to the lower base 40, and the lower base 40 is connected to the first connection pipe 36 and the second connection pipe 37, respectively, the first control valve 32 is mounted to the upper base 39, and the upper base 39 is connected to the first connection pipe 36 and the second connection pipe 37, respectively. By providing the upper base 39 and the lower base 40, the overall stability among the first suction oil pump 31, the first connection pipe 36, the second connection pipe 37, and the first control valve 32 can be effectively enhanced. Further, the oil suction valve 3 further comprises a fixing member (not shown in the drawings) fixedly connected to the first connecting pipe 36 and the second connecting pipe 37, respectively, and the fixing member is located between the upper base 39 and the lower base 40. The stability between the first connection pipe 36 and the second connection pipe 37 can be further enhanced by providing a fixing member.

Optionally, the suction valve 3 further comprises a conduit, not shown in the drawings), for passing through the power and control lines of the first suction pump 31 and for passing through the power and control lines of the first electric heating element 33. Since the first oil suction pump 31 and the first electric heating member 33 are both located in the first fuel tank 2, the safety of electricity consumption can be ensured by providing the line pipe.

Optionally, the suction valve 3 further comprises a float pipe 38, the float pipe 38 is communicated with the first fuel tank 2, and the float pipe 38 is made of transparent material. By providing the float tube 38, it is convenient to observe the amount of fuel in the first fuel tank 2.

Optionally, as shown in fig. 7, the oil suction valve 3 further comprises a temperature sensor 41, and the temperature sensor 41 is used for detecting the external environment temperature. The fuel condition in the first fuel tank 2 can be evaluated as a function of the ambient temperature.

In this embodiment, the upper base 39 is further fixedly provided with a circuit board 42, and the circuit board 42 is connected to the temperature sensor 41, the first oil suction pump 31, the first electric heating member 33, and the first control valve 32 through electric wires, respectively.

After the engine 1 is operated, the hot oil which returns to the first fuel tank 2 through the oil return line 52 can melt the solid fuel, if the solid fuel is melted only by the returned hot oil, it takes a certain time to change the fuel in the whole first fuel tank 2 into liquid, during which the fuel state at the input port of the first oil suction pump 31 is slowly improved, and the heat of the hot oil which returns to the first fuel tank 2 through the oil return line 52 is not utilized most effectively.

In contrast, as shown in fig. 8, in the present embodiment, one end of the oil return line 52 extending into the first fuel tank 2 is blocked, an oil return hole 521 is provided in a side wall of the oil return line 52, and the oil return hole 521 faces the input port of the first oil suction pump 31. After the fuel in the first fuel tank 2 is solidified and the engine 1 is successfully started, hot oil which is not combusted in the engine 1 can be sprayed towards the input port of the first oil suction pump 31 through the oil return hole 521 of the oil return pipeline 52, so that the melting speed of the fuel at the input port of the first oil suction pump 31 can be accelerated, the heat of the return oil can be fully utilized, and the load of the first electric heating element 33 can be reduced.

Wherein, the flow area of the oil return hole 521 is 50mm²～180mm². For example, the flow area of the oil return hole 521 may be 50mm²、60mm²、70mm²、80mm²、90mm²、100mm²、110mm²、120mm²、130mm²、140mm²、150mm²、160mm²、170mm²Or 180mm²。

It will be appreciated that the hot oil injected at the input of the first oil suction pump 31 also heats the first filter simultaneously. Specifically, optionally, the difference between the level of the oil return hole 521 and the level of the first sieve 34 is ± 20 mm. Illustratively, the difference between the level of the oil return hole 521 and the level of the first screen 34 may be 0mm, ± 1mm, ± 2mm, ± 3mm, ± 4mm, ± 5mm, ± 6mm, ± 7mm, ± 8mm, ± 9mm, ± 10mm, ± 11mm, ± 12mm, ± 13mm, ± 14mm, ± 15mm, ± 16mm, ± 17mm, ± 18mm, ± 19mm or ± 20 mm.

Optionally, as shown in fig. 9, the oil suction valve 3 further includes a box 43, the box 43 is located in the first fuel tank 2, an opening 431 is formed at the top of the box 43, the opening 431 is communicated with the accommodating cavity inside the box 43, and the input port of the first oil suction pump 31 and the oil return hole 521 on the oil return pipeline 52 are located in the box 43. Through the arrangement of the box body 43, the hot oil returned by the oil return pipeline 52 and the fuel oil sucked from the first oil suction pump 31 circulate through the space in the box body 43, so that the influence of the external cold quantity of the box body 43 can be isolated to a certain extent, and the utilization rate of the heat of the oil return hot oil is further improved.

Optionally, the box 43 is provided with several through holes, which penetrate through the side walls of the box 43. Through setting up the through-hole, when the fuel in box 43 all melts to liquid, heat accessible through-hole outwards gives off, and simultaneously, the outside fuel of box 43 still can get into to the box 43 through the through-hole and provide first oil absorption pump 31 in. Preferably, each side wall of the box body 43 is a screen mesh, and the mesh of the screen mesh forms through holes.

The hot oil returned from the return line of the engine 1 is advantageous for the solidified fuel in the first fuel tank 2, but in summer, the temperature of the external environment is high, and if the hot oil returned from the return line of the engine 1 is re-sucked into the fuel supply line 51 by the first check valve 35, the temperature of the fuel delivered to the engine 1 is easily too high, which is not favorable for combustion.

In this regard, referring to fig. 9, in the present embodiment, the input port of the first check valve 35 sucks oil from the outside of the box 43. It will be appreciated that when the ambient temperature is high and the fuel in the first fuel tank 2 is in a liquid state, and when the engine 1 is started, the transfer pump 61 is turned on and the first suction pump 31 is turned off, the transfer pump 61 can suck the fuel from the outside of the case 43 through the first check valve 35, and the hot oil returned from the return line 52 is in the case 43, so that the returned hot oil can be separated from the fuel sucked into the supply line 51 through the first check valve 35 to prevent the temperature of the fuel supplied to the engine 1 from being too high. Specifically, the first check valve 35 is located in the case 43, and a connection line between the input port of the first check valve 35 and the first fuel tank 2 passes through the case 43 and extends below the case 43.

The present embodiment can store fuel by the first fuel tank 2, but if the fuel quantity is insufficient and the fuel cannot reach the filling station before the fuel is exhausted during the running of the vehicle, the vehicle is easily broken down.

In this regard, as shown in fig. 10 to 12, the fuel supply system according to the present embodiment further includes a second fuel tank 81, a second suction pump 82, and a fuel replenishment pipe 83. The second fuel tank 81 is used for storing fuel oil with the same label as that in the first fuel tank 2, namely 0# fuel oil, an input port of the second suction pump 82 sucks the fuel oil from the second fuel tank 81, an output port of the second suction pump 82 is connected with an oil supplementing pipe 83, and the oil supplementing pipe 83 extends into the first fuel tank 2. The spare fuel is reserved in the second fuel tank 81, and when the fuel in the first fuel tank 2 is insufficient, the fuel in the second fuel tank 81 can be supplemented to the first fuel tank 2 through the fuel supplementing pipe 83 by the second suction pump 82 to supply to the engine 1, so that the vehicle can be prevented from being anchored.

Optionally, the fuel supply system further comprises a second check valve 84, an input port of the second check valve 84 is communicated with the second fuel tank 81, an output port of the second check valve 84 is communicated with an output port of the first suction pump 31, and the second check valve 84 is configured to allow only fuel to flow from the second fuel tank 81 to the output port of the second suction pump 82 via the second check valve 84. By arranging the second check valve 84, when the fuel level in the second fuel tank 81 is higher than the fuel level in the first fuel tank 2 by a certain value, under the siphon action, the fuel in the second fuel tank 81 can be supplemented into the first fuel tank 2 through the second check valve 84 and the oil supplementing pipeline, so that the second oil suction pump 82 does not need to be started, and the electric energy is saved.

Alternatively, the length of the connecting pipeline between the input port of the second check valve 84 and the second fuel tank 81 is 0mm to 100 mm; and/or the length of the connecting pipeline between the output port of the second one-way valve 84 and the output port of the second oil suction pump 82 is 0 mm-200 mm. For example, the length of the connecting line between the input port of the second check valve 84 and the second fuel tank 81 may be 0mm, 50mm or 100 mm; the length of the connecting line between the output port of the second check valve 84 and the output port of the second oil suction pump 82 may be 0mm, 50mm, 100mm, 150mm, or 200 mm.

Optionally, the connection line between the input port of the second check valve 84 and the second fuel tank 81 is provided with a filter screen. The filter screen can prevent the impurities in the second fuel tank 81 from entering the first fuel tank 2. Wherein, the filter screen in this embodiment can be the filter screen of square grid mesh shape, and the mesh size of filter screen then can set up as required.

Alternatively, the flow area of the connecting line between the input port of the second check valve 84 and the second fuel tank 81, and the flow area of the connecting line between the output port of the second check valve 84 and the output port of the second oil suction pump 82 are both 50mm²～180mm². By such arrangement, the oil resistance of the pipeline where the second check valve 84 is located can be effectively reduced. Illustratively, the flow areas of the connecting lines between the input port of the second check valve 84 and the second fuel tank 81 and the flow areas of the connecting lines between the output port of the second check valve 84 and the output port of the second oil suction pump 82 are both 50mm²、60mm²、70mm²、80mm²、90mm²、100mm²、110mm²、120mm²、130mm²、140mm²、150mm²、160mm²、170mm²Or 180mm²。

Optionally, the ball of the second check valve 84 has a density less than the density of the liquid fuel. Specifically, the ball of the second one-way valve 84 has a density of 0.5g/ml to 0.8 g/ml. Illustratively, the ball of the second one-way valve 84 may have a density of 0.5g/ml, 0.55g/ml, 0.6g/ml, 0.65g/ml, 0.7g/ml, 0.75g/ml, or 0.8 g/ml. So set up, the valve ball of second check valve 84 can float in liquid fuel, is difficult to take place the jamming with the valve casing of second check valve 84, guarantees second check valve 84's stability.

Alternatively, as shown in fig. 11, both the second oil suction pump 82 and the second check valve 84 are disposed in the second fuel tank 81 at the bottom of the second fuel tank 81. Specifically, the distance between the input port of the second oil suction pump 82 and the bottom surface of the second fuel tank 81 is 15mm to 100 mm. With such an arrangement, effective utilization of the fuel in the second fuel tank 81 is not affected, and the solidified fuel can be effectively delivered to the input port of the second oil suction pump 82. Illustratively, the distance between the input port of the second oil suction pump 82 and the bottom surface of the second fuel tank 81 may be 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, or 100 mm.

As an alternative, the second oil suction pump 82 and the second check valve 84 are both disposed in the second fuel tank 81 and located at the top of the second fuel tank 81, an input port of the second oil suction pump 82 is connected to the first extension pipe 87, an input port of the second check valve 84 is connected to the second extension pipe, and the first extension pipe 87 and the second extension pipe both extend to the bottom of the second fuel tank 81. As an alternative thereto, the second extension pipe may also communicate with the first extension pipe 87, so that the second extension pipe need not extend to the bottom of the second fuel tank 81. In the present embodiment, the distance from the second oil suction pump 82 to the top surface of the second fuel tank 81 is 0mm to 800mm, and the distance from the second oil suction pump 82 to the top surface of the second fuel tank 81 may be 0mm, 100mm, 200mm, 300mm, 400mm, 500mm, 600mm, 700mm, or 800mm, for example.

Optionally, the fuel supply system further comprises a second screen 86 and a second electric heating element 85 disposed in the second fuel tank 81; a second sieve 86 is located below the input of the second oil suction pump 82 and a second electric heating element 85 is located below the second sieve 86. With this arrangement, the fuel near the second filter screen 86 can be heated by the second electric heating element 85, and particularly after the fuel in the second fuel tank 81 is solidified, the fuel on the second filter screen 86 can be melted by the heating of the second electric heating element 85, so that the fuel can smoothly enter the second oil suction pump 82 or the second check valve 84. The second filter 86 can filter impurities in the fuel in the second fuel tank 81, and can cut large solid fuel into small pieces to ensure that the solid fuel entering the second oil suction pump 82 can be pumped normally through the second oil suction pump 82.

The embodiment also provides an oil supply method of the fuel supply system. The fuel supply method of the fuel supply system is different according to different actual working conditions.

The working condition I is as follows: before the engine 1 is started, the fuel at the input port of the first suction pump 31 is in a solid state.

It is shown that the ambient temperature is relatively low, and the solid fuel in the first fuel tank 2 needs to be melted before being delivered to the engine 1.

The fuel supply method of the fuel supply system comprises the following steps: the second control valve disconnects the bypass line 62, the first control valve 32 controls the oil supply line 51 and the oil return line 52 to communicate, and the first oil suction pump 31 is opened.

At this time, under the driving of the first suction pump 31, the fuel circulates along the path of the first fuel tank 2, the first suction pump 31, the fuel supply pipeline 51, the first control valve 32, the fuel return pipeline 52 and the first fuel tank 2, and the solidified fuel in the first fuel tank 2 can be rapidly heated and thawed under the action of the first suction pump 31. It should be noted that this operation is not necessary when the fuel in the first fuel tank 2 is in a liquid state.

Working conditions are as follows: the engine 1 is about to start.

It is explained that the fuel in the first fuel tank 2 is at least partly liquid and can be supplied normally to the engine 1.

The fuel supply method of the fuel supply system comprises the following steps: the second control valve is communicated with the bypass line 62, the first control valve 32 controls the oil supply line 51 and the oil return line 52 to be disconnected, and the first oil suction pump 31 is opened.

At this time, under the driving of the first suction pump 31, the fuel circulates along the path of the first fuel tank 2-the first suction pump 31-the bypass line 62-the engine 1-the oil return line 52-the first fuel tank 2. The oil supply line 51 and the oil return line 52 are not communicated with each other, and the engine 1 can perform an ignition operation.

Working conditions are as follows: after the engine 1 is started and the fuel in the first fuel tank 2 is at least partly in a solid state.

Indicating that further melting of the fuel in the first fuel tank 2 is still required.

At this point, the feed pump 61 has started and, under the negative pressure supplied by the feed pump 61, fuel circulates along the path of the first fuel tank 2-the first check valve 35-the feed pump 61-the engine 1-the return line 52-the first control valve 32-the feed line 51. Due to the communication between the oil supply pipeline 51 and the oil return pipeline 52, hot oil returning from the engine 1 can enter the oil supply pipeline 51 through the oil return pipeline 52, so that the temperature of the fuel oil delivered to the oil supply pipeline 51 by the first check valve 35 is raised to be above 4 ℃. Of the fuel delivered to the fuel delivery pump 61, 90% comes from the return line 52 and 10% comes from the first check valve 35.

Working conditions are as follows: after the engine 1 is started, the fuel at the input port of the first suction pump 31 is in a liquid state.

The engine 1 can normally supply fuel at this time, and the fuel does not need to be heated.

The fuel supply method of the fuel supply system comprises the following steps: the second control valve disconnects the bypass line 62, the first control valve 32 controls the oil supply line 51 and the oil return line 52 to be disconnected, and the first oil suction pump 31 is closed.

At this point, the fuel delivery pump 61 has started and, under the negative pressure supplied by the fuel delivery pump 61, fuel circulates along the path of the first fuel tank 2-first check valve 35-supply line 51-fuel delivery pump 61-supply line 51-engine 1-return line 52-first fuel tank 2.

Working condition five: the fuel level in the second fuel tank 81 is higher than the fuel level in the first fuel tank 2, and the difference in height between the fuel level in the second fuel tank 81 and the fuel level in the first fuel tank 2 does not exceed a set value.

Indicating that the fuel in the first fuel tank 2 is insufficient and that it needs to be replenished, the set value may be an empirical value.

The fuel supply method of the fuel supply system comprises the following steps: the second oil suction pump 82 is turned on.

After the second suction pump 82 is turned on, the second suction pump 82 can replenish the fuel in the second fuel tank 81 to the first fuel tank 2. When the height difference between the fuel level in the second fuel tank 81 and the fuel level in the first fuel tank 2 is greater than the set value, the fuel in the second fuel tank 81 can flow into the first fuel tank 2 through the second check valve 84 and the fuel replenishing pipe 83 under the siphon action.

Working condition five: the fuel level in the second fuel tank 81 is higher than the fuel level in the first fuel tank 2. And the difference in height between the fuel level in the second fuel tank 81 and the fuel level in the first fuel tank 2 is greater than a set value.

The fuel supply method of the fuel supply system comprises the following steps: the second suction pump 82 is turned off.

Indicating that the fuel in the first fuel tank 2 is insufficient, the fuel needs to be replenished, and the fuel in the second fuel tank 81 can automatically flow into the first fuel tank 2 through the second check valve 84 and the fuel replenishing pipe 83 under the siphon action.

The embodiment also provides a diesel engine assembly, which comprises the oil suction valve 3, the oil pump assembly or the fuel supply system in the scheme.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A fuel supply system, includes first fuel tank (2), set up in first oil absorption pump (31) and first check valve (35) in first fuel tank (2), first oil absorption pump (31) are used for following draw fuel in first fuel tank (2) and supply engine (1), first check valve (35) set up in first fuel tank (2) with between the delivery outlet of first oil absorption pump (31), just first check valve (35) are configured as and only allow fuel in first fuel tank (2) warp first check valve (35) to the delivery outlet of first oil absorption pump (31) is carried, its characterized in that, the fuel supply system still includes:

a second fuel tank (81), said second fuel tank (81) being adapted to store fuel of the same grade as in said first fuel tank (2);

the fuel oil pump comprises a second oil suction pump (82) and an oil supplementing pipe (83), an input port of the second oil suction pump (82) is used for sucking fuel oil in a second fuel oil tank (81), an output port of the second oil suction pump (82) is connected with the oil supplementing pipe (83), and the oil supplementing pipe (83) stretches into the first fuel oil tank (2).

2. A fuel supply system according to claim 1, characterized in that it further comprises a second one-way valve (84), the input of said second one-way valve (84) communicating with said second fuel tank (81), the output of said second one-way valve (84) communicating with the output of said first suction pump (31), said second one-way valve (84) being configured to allow fuel to flow only from said second fuel tank (81) to the output of said second suction pump (82) via said second one-way valve (84).

3. A fuel supply system according to claim 2, characterized in that the length of the connecting line between the inlet port of the second check valve (84) and the second fuel tank (81) is 0mm to 100 mm; and/or the presence of a gas in the gas,

the length of a connecting pipeline between the output port of the second one-way valve (84) and the output port of the second oil suction pump (82) is 0-200 mm.

4. A fuel supply system according to claim 2, characterized in that the connecting line between the inlet of the second non return valve (84) and the second fuel tank (81) is provided with a filter screen.

5. A fuel supply system according to claim 2, characterized in that the flow area of the connecting line between the inlet of the second non return valve (84) and the second fuel tank (81) and the flow area of the connecting line between the outlet of the second non return valve (84) and the outlet of the second suction pump (82) are both 50mm²～180mm²。

6. A fuel supply system according to claim 2, characterized in that the ball of the second non return valve (84) has a density lower than the density of the liquid fuel.

7. A fuel supply system according to claim 2, characterized in that said second suction pump (82) and said second one-way valve (84) are both arranged inside said second tank (81) and at the bottom of said second tank (81); alternatively, the first and second electrodes may be,

the second oil suction pump (82) and the second one-way valve (84) are both arranged in the second fuel tank (81) and located at the top of the second fuel tank (81), an input port of the second oil suction pump (82) is connected with a first extension pipe (87), an input port of the second one-way valve (84) is connected with a second extension pipe, and the first extension pipe (87) and the second extension pipe both extend to the bottom of the second fuel tank (81).

8. A fuel supply system according to claim 1, characterized in that it further comprises a first sieve (34) and a first electric heating element (33) arranged in the first fuel tank (2); the first filter screen (34) is positioned below an input port of the first oil suction pump (31), and the first electric heating element (33) is positioned below the first filter screen (34); and/or the presence of a gas in the gas,

the fuel supply system also comprises a second filter screen (86) and a second electric heating element (85) which are arranged in the second fuel tank (81); the second filter screen (86) is positioned below the input port of the second oil suction pump (82), and the second electric heating element (85) is positioned below the second filter screen (86).

9. A fuel supply method of a fuel supply system according to any one of claims 1 to 8, comprising:

when the fuel level in the second fuel tank (81) is higher than the fuel level in the first fuel tank (2) and the difference between the fuel level in the second fuel tank (81) and the fuel level in the first fuel tank (2) does not exceed a set value, the second suction pump (82) is turned on.

10. The fuel supply method of the fuel supply system according to claim 9, characterized in that the fuel supply system further comprises a second check valve (84), an input port of the second check valve (84) communicates with the second fuel tank (81), an output port of the second check valve (84) communicates with an output port of the first suction pump (31), and the second check valve (84) is configured to allow only fuel to flow from the second fuel tank (81) to the output port of the second suction pump (82) through the second check valve (84);

the fuel supply method of the fuel supply system further includes:

-the second suction pump (82) is switched off when the fuel level in the second tank (81) is higher than the fuel level in the first tank (2) and the difference in height between the fuel level in the second tank (81) and the fuel level in the first tank (2) is greater than a set value;

when the height difference between the fuel level in the second fuel tank (81) and the fuel level in the first fuel tank (2) is larger than a set value, the fuel in the second fuel tank (81) can flow into the first fuel tank (2) through the second one-way valve (84) and the fuel supplementing pipe (83).