Fuel oil supply system and method for bulldozer in cold region

Abstract

The invention discloses a fuel supply system and method for a bulldozer in a cold region. The system comprises a main fuel tank, an auxiliary fuel tank and a fuel reversing valve. An oil outlet of the main oil tank is communicated with a first oil inlet of the fuel oil reversing valve; an oil return port of the main oil tank is communicated with a first oil return port of the fuel reversing valve; an oil outlet of the auxiliary oil tank is communicated with a second oil inlet of the fuel oil reversing valve; an oil return port of the auxiliary oil tank is communicated with a second oil return port of the fuel oil reversing valve; when the engine is started, the fuel oil reversing valve is in a state that the second oil inlet is communicated with the reversing valve oil outlet and the third oil return port is communicated with the second oil return port; after the engine is started for a first set time, the fuel oil reversing valve is in a state that a first oil inlet is communicated with an oil outlet of the reversing valve and a third oil return port is communicated with a second oil return port; and after the engine is started for a second set time, the fuel oil reversing valve is in a state that the first oil inlet is communicated with the reversing valve oil outlet and the third oil return port is communicated with the first oil return port. Diesel oil can be effectively prevented from being mixed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine fuel supply, in particular to a kind of cold region bulldozer fuel supply system and method. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] In order for the bulldozer in the high-cold or extremely cold region to work normally, high-grade diesel oil needs to be added to the bulldozer; in order to reduce the use of high-grade diesel oil and thus reduce the use cost, in the related art, there is a technical solution that high-grade diesel oil is used at the initial start of the engine, and then low-grade diesel oil is used to supply oil to the engine.

[0004] However, in the related technical solution, when switching from high-grade diesel oil to low-grade diesel oil to supply oil to the engine, the engine directly returns oil to the oil tank containing low-grade diesel oil, resulting in oil mixing when the high-grade diesel oil finally supplied to the engine is returned to the low-grade diesel oil, which causes unpredictable changes in the freezing point of diesel oil.

[0005] Secondly, the current bulldozer in the high-cold or extremely cold region can only follow the sequence of first supplying high-grade diesel oil and then supplying low-grade diesel oil when the ambient temperature is high; resulting in a still high use rate of high-grade diesel oil. SUMMARY

[0006] To solve the above problems, the present application proposes a kind of cold region bulldozer fuel supply system and method, effectively prevent diesel oil mixing, and effectively reduce the use rate of high-grade diesel oil, reduce the use cost of bulldozer, improve the performance stability of bulldozer.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: In a first aspect, the present application proposes a kind of cold region bulldozer fuel supply system, comprising: main oil tank, auxiliary oil tank and fuel reversing valve;The main oil tank contains low-grade diesel oil, and the auxiliary oil tank contains high-grade diesel oil; The first oil inlet, the second oil inlet, the first oil return port, the second oil return port, the reversing valve oil outlet and the third oil return port are arranged on the fuel reversing valve;The oil inlet of the engine is communicated with the reversing valve oil outlet of the fuel reversing valve;The oil return port of the engine is communicated with the third oil return port of the fuel reversing valve; The oil outlet of the main oil tank is communicated with the first oil inlet of the fuel reversing valve;The oil return port of the main oil tank is communicated with the first oil return port of the fuel reversing valve;The oil outlet of the auxiliary oil tank is communicated with the second oil inlet of the fuel reversing valve;The oil return port of the auxiliary oil tank is communicated with the second oil return port of the fuel reversing valve; When the engine starts, the fuel reversing valve is in a state that the second inlet is connected with the reversing valve outlet, and the third return port is connected with the second return port; After the engine starts for a first set time, the fuel reversing valve is in a state that the first inlet is connected with the reversing valve outlet, and the third return port is connected with the second return port; After the engine starts for a second set time, the fuel reversing valve is in a state that the first inlet is connected with the reversing valve outlet, and the third return port is connected with the first return port.

[0008] Further, the first oil outlet flange is arranged at the oil outlet of the main oil tank; the heat exchanger is arranged on the first oil outlet flange; the first oil outlet flange is communicated with the first inlet of the fuel reversing valve; the heat exchanger is communicated with the heating inlet water pipe and the heating outlet water pipe; and the heat exchanger extends into the main oil tank from the oil outlet of the main oil tank.

[0009] Further, the heating inlet water pipe is communicated with the engine cooling liquid outlet; and the heating outlet water pipe is communicated with the engine cooling liquid inlet.

[0010] Further, the reversing valve outlet of the fuel reversing valve is communicated with the inlet of the engine through the engine inlet pipe; The heating device is arranged on the engine inlet pipe, and the heating device is used for heating the engine inlet pipe.

[0011] Further, the heating device is used for starting when the first inlet of the fuel reversing valve is connected with the reversing valve outlet, and is used for stopping when the second inlet of the fuel reversing valve is connected with the reversing valve outlet.

[0012] Further, the main oil tank and the auxiliary oil tank are both provided with a drain port.

[0013] Further, the volume of the main oil tank is greater than the volume of the auxiliary oil tank.

[0014] Further, the fuel reversing valve is connected with the switch; and the switch is used for controlling the state switching of the fuel reversing valve.

[0015] In the second aspect, the application further provides a fuel supply method of the fuel supply system of the bulldozer in the cold region. When the engine starts, the fuel reversing valve is switched to a state that the second inlet is connected with the reversing valve outlet, and the third return port is connected with the second return port, high-grade diesel oil is supplied to the engine, and the high-grade diesel oil in the engine is returned to the auxiliary oil tank; After the engine starts for a first set time, the fuel reversing valve is switched to a state that the first inlet is connected with the reversing valve outlet, and the third return port is connected with the second return port, low-grade diesel oil is supplied to the engine, and the high-grade diesel oil in the engine is returned to the auxiliary oil tank; After the engine is started for a second set time, the fuel reversing valve is switched to a state of connecting the first oil inlet with the reversing valve oil outlet and connecting the third oil return port with the first oil return port, so as to provide low-grade diesel oil for the engine and return the low-grade diesel oil in the engine to the main oil tank.

[0016] Further, the heating device on the engine oil inlet pipe is started when the first oil inlet of the fuel reversing valve is connected with the reversing valve oil outlet, and the heating device on the engine oil inlet pipe is closed when the second oil inlet of the fuel reversing valve is connected with the reversing valve oil outlet.

[0017] Compared with the prior art, the present application has the following beneficial effects: The present application provides a cold region bulldozer fuel supply system and method, which comprises a main oil tank containing low-grade diesel oil and a secondary oil tank containing high-grade diesel oil, and the main oil tank and the secondary oil tank are connected with an engine through a fuel reversing valve; the fuel reversing valve has a time delay function, and when the engine is started, the engine is supplied with high-grade diesel oil, and the high-grade diesel oil in the engine is returned to the secondary oil tank; when the engine is started for a period of time and the water temperature of the engine is increased, the engine is supplied with low-grade diesel oil, and the high-grade diesel oil in the engine is returned to the secondary oil tank; after a period of time, the high-grade diesel oil in the engine is completely returned to the secondary oil tank, the engine is supplied with low-grade diesel oil, and the low-grade diesel oil in the engine is returned to the main oil tank, thereby effectively preventing oil mixing and ensuring the stability of the bulldozer performance. On the basis of ensuring the normal operation of the bulldozer in the cold region, the use amount of high-grade diesel oil is reduced, and the use cost of the bulldozer is further reduced.

[0018] In addition, the present application provides a cold region bulldozer fuel supply system, which further comprises a switching switch connected with the fuel reversing valve, and by controlling the switching switch, the connection state of the fuel reversing valve can be changed, so that in a normal temperature or high temperature environment, the engine can be directly supplied with low-grade diesel oil by controlling the switching switch, thereby further reducing the use rate of high-grade diesel oil and reducing the use cost of the bulldozer.

[0019] The advantages of the additional aspects of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0020] The drawings constituting a part of the specification of the present application are used to provide a further understanding of the present application, the illustrative embodiments of the present application and the description thereof are used to explain the present application, and do not constitute an improper limitation on the present application.

[0021] Figure 1 A structure schematic diagram of a cold region bulldozer fuel supply system according to an embodiment of the present application is shown in the figure; Figure 2The schematic diagram of the fuel tank structure provided by the embodiment of the present application is shown in the figure. Figure 3 The schematic diagram of the second oil outlet flange structure provided by the embodiment of the present application is shown in the figure. Figure 4 The schematic diagram of the fuel reversing valve structure provided by the embodiment of the present application is shown in the figure. Figure 5 The control signal flow chart provided by the embodiment of the present application is shown in the figure. Figure 6 The control circuit framework chart provided by the embodiment of the present application is shown in the figure.

[0022] In the figure, 1 is a main oil tank, 2 is a secondary oil tank, 3 is a fuel reversing valve, 4 is a second oil outlet flange, 5 is a first oil outlet flange, 6 is a main oil tank drain, 7 is a secondary oil tank drain, 8 is a second oil inlet pipe, 9 is a second oil return pipe, 10 is a first oil return pipe, 11 is a first oil inlet pipe, 12 is an engine oil inlet pipe, 13 is an engine oil return pipe, 14 is a heating water inlet pipe, 15 is a heating water return pipe, 16 is a partition plate, 17 is a heating water inlet, 18 is a heating water return, 19 is a heat exchanger, 20 is a heating water inlet, 21 is a heating water return, 22 is a first oil inlet, 23 is a second oil inlet, 24 is a first oil return, and 25 is a second oil return. DETAILED DESCRIPTION

[0023] The present application will be further described below in conjunction with the accompanying drawings and embodiments.

[0024] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains.

[0025] It should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that when the terms "comprise" and / or "include" are used in the specification, there is a presence of a feature, step, operation, device, component, and / or a combination thereof.

[0026] In the present application, the terms such as "fixedly connected", "connected", "connected" and the like should be understood broadly, which means that it can be fixedly connected, integrally connected or detachably connected; it can be directly connected or indirectly connected through an intermediate medium. For relevant researchers or technicians in the art, the specific meaning of the above terms in the present application can be determined according to the specific circumstances, and should not be understood as a limitation of the present application.

[0027] First, the application scenario of a bulldozer fuel supply system proposed in the embodiment of the application is described.

[0028] The bulldozer fuel supply system proposed in the embodiment of the application is applied to the application background of a bulldozer in an alpine or polar region.

[0029] In order for the bulldozer in an alpine or polar region to work normally, the bulldozer needs to be refueled with high-grade diesel.

[0030] The grade of diesel is mainly divided according to its freezing point (i.e. the temperature at which it begins to freeze at low temperature), indicating the applicability of diesel at different temperatures. The common diesel grade and its interpretation are shown as follows:

[0031] The diesel grade should be about 5℃ lower than the local minimum temperature, because diesel will first precipitate wax before the freezing point, which is easy to block the filter.

[0032] The low-grade diesel is 0# diesel, and the high-grade diesel can be -35# or -50# diesel. In cold regions, the price of high-grade diesel is much higher than that of low-grade diesel. The price of some high-grade diesel in winter may be 20%-30% higher than that of low-grade diesel. Therefore, in order to reduce the fuel cost of the bulldozer, it is necessary to reduce the use of high-grade diesel as much as possible.

[0033] In the related art, there is a technical solution that high-grade diesel is used at the initial start of the engine, and then low-grade diesel is used to supply oil to the engine.

[0034] However, in the related technical solution, when the high-grade diesel is switched to the low-grade diesel to supply oil to the engine, the engine directly returns oil to the oil tank containing the low-grade diesel, which causes the high-grade diesel finally supplied to the engine to mix with the low-grade diesel, resulting in unpredictable changes in the freezing point of the diesel, thereby affecting the stability of the bulldozer performance.

[0035] Secondly, in the alpine or polar region, it is not always extremely cold or alpine weather all year round. The environmental temperature in summer is also relatively high. In the normal or high temperature environment, the current bulldozer in the alpine or polar region can only follow the order of first being supplied with high-grade diesel and then being supplied with low-grade diesel; resulting in a still high use rate of high-grade diesel.

[0036] This invention, in order to reduce the use of high-grade diesel fuel, lower the fuel cost of bulldozers, and prevent the mixing of high-grade and low-grade diesel fuel, proposes a fuel supply system for bulldozers operating in cold regions. The system includes a main fuel tank for low-grade diesel fuel and an auxiliary fuel tank for high-grade diesel fuel. Both tanks are connected to the engine via a fuel reversing valve. This valve has a delay function: when the engine is first started, high-grade diesel fuel is supplied, and the engine fuel is returned to the auxiliary tank. After the engine has been running for a period and the engine coolant temperature has risen, low-grade diesel fuel is supplied, and the last high-grade diesel fuel supplied to the engine is returned to the auxiliary tank. After another period, once all the high-grade diesel fuel has returned to the auxiliary tank, low-grade diesel fuel is supplied, and the low-grade diesel fuel in the engine returns to the main fuel tank. This effectively prevents mixing and ensures the stability of the bulldozer's performance. While ensuring the bulldozer can operate normally in cold regions, this system reduces the use of high-grade diesel fuel, thereby lowering the bulldozer's operating costs.

[0037] Furthermore, the fuel supply system for a bulldozer in cold regions proposed in this invention also includes a switching switch connected to a fuel reversing valve. By operating the switching switch, the on / off state of the fuel reversing valve can be changed. Thus, in normal or high temperature environments, the engine can be directly supplied with low-grade diesel fuel by operating the switching switch, further reducing the usage rate of high-grade fuel and lowering the operating cost of the bulldozer.

[0038] like Figures 1-6 As shown in the figure, an embodiment of the present invention proposes a fuel supply system for bulldozers in cold regions, comprising: a main fuel tank 1, an auxiliary fuel tank 2, and a fuel reversing valve 3; the main fuel tank 1 contains low-grade diesel fuel, and the auxiliary fuel tank 2 contains high-grade diesel fuel. The fuel reversing valve 3 is provided with a first fuel inlet 22, a second fuel inlet 23, a first fuel return port 24, a second fuel return port 25, a reversing valve outlet, and a third fuel return port; the engine's fuel inlet is connected to the reversing valve outlet of the fuel reversing valve 3; the engine's fuel return port is connected to the third fuel return port of the fuel reversing valve 3. The outlet of the main fuel tank 1 is connected to the first inlet of the fuel reversing valve 3; the return port of the main fuel tank 1 is connected to the first return port of the fuel reversing valve 3; the outlet of the auxiliary fuel tank 2 is connected to the second inlet of the fuel reversing valve 3; and the return port of the auxiliary fuel tank 2 is connected to the second return port of the fuel reversing valve 3. When the engine starts, the fuel reversing valve 3 is in the state where the second oil inlet is connected to the reversing valve outlet and the third oil return port is connected to the second oil return port, supplying high-grade diesel fuel to the engine and returning the high-grade diesel fuel in the engine to the auxiliary oil tank 2. After the engine starts for the first set time, the fuel reversing valve 3 is in the state where the first oil inlet is connected to the reversing valve outlet and the third oil return port is connected to the second oil return port, providing low grade diesel to the engine and returning the high grade diesel that was last introduced into the engine to the auxiliary oil tank 2. After the engine starts for the second set time, the fuel reversing valve 3 is in a state where the first oil inlet is connected to the reversing valve outlet and the third oil return port is connected to the first oil return port, supplying low-grade diesel fuel to the engine and returning the low-grade diesel fuel in the engine to the main fuel tank 1.

[0039] This has changed the problem of bulldozers using more high-octane diesel fuel in cold temperatures, reducing fuel costs for bulldozer operations in cold regions.

[0040] Since bulldozers primarily rely on low-grade diesel fuel, this embodiment of the invention limits the volume of the main fuel tank 1 to be larger than the volume of the auxiliary fuel tank 2, such as... Figure 2 As shown, in this embodiment of the invention, the main oil tank 1 and the auxiliary oil tank 2 are integrated together, and the two oil tanks are separated only by a partition 16.

[0041] Both the main fuel tank and the auxiliary fuel tank are equipped with drain ports to facilitate the removal of water separated from the diesel fuel in the main and auxiliary fuel tanks. For example... Figure 1 As shown, the main oil tank 1 is equipped with a main oil tank drain outlet 6, and the auxiliary oil tank 2 is equipped with an auxiliary oil tank drain outlet 7.

[0042] The fuel reversing valve 3 in this embodiment of the invention has a delayed reversing function. Essentially, it is a two-position three-way valve that uses a solenoid valve to drive valve cores of different fuel supply channels to switch between different fuel supply and return lines. The delayed return switching function of this reversing valve is achieved by setting a differential action during solenoid valve switching. After the inlet line completes switching, to prevent fuel mixing from affecting engine operation, the return valve core completes the switching action after a certain period. Simultaneously, this reversing valve has an automatic switching function to prevent the driver from accidentally using the auxiliary fuel tank continuously or forgetting to switch to the auxiliary fuel tank when parking, which could prevent the vehicle from starting later.

[0043] The structure of fuel reversing valve 3 is as follows Figure 4As shown, the fuel reversing valve 3 is provided with a first fuel inlet, a second fuel inlet, a first return fuel inlet, a second return fuel inlet, a reversing valve outlet, and a third return fuel inlet. The fuel reversing valve 3 is provided with an inlet channel valve core and a return fuel channel valve core. The inlet channel valve core is provided with a first inlet channel and a second inlet channel. When the inlet channel valve core is in the first position, the first inlet channel is connected to the first fuel inlet and the reversing valve outlet, and the second inlet channel is closed. When the inlet channel valve core is in the second position, the first inlet channel is closed, and the second inlet channel is connected to the second fuel inlet and the reversing valve outlet. The return fuel channel valve core is provided with a first return fuel channel and a second return fuel channel. When the return fuel channel valve core is in the first position, the first return fuel channel is connected to the first return fuel inlet and the third return fuel inlet, and the second return fuel channel is closed. When the return fuel channel valve core is in the second position, the first return fuel channel is closed, and the second return fuel channel is connected to the second return fuel inlet and the third return fuel inlet.

[0044] The oil inlet valve core and the oil return valve core are rotated by an electric motor in conjunction with corresponding transmission gears.

[0045] In some embodiments, the fuel reversing valve 3 is connected to a switching switch; the switching switch is used to control the state switching of the fuel reversing valve 3.

[0046] When the operator presses the switch in the cab (i.e., the main fuel tank command), the control circuit detects the operator's switching command. Based on this command, the solenoid valve in fuel reversing valve 3 is energized, causing the fuel inlet valve core to rotate 90°, connecting the first fuel inlet to the reversing valve outlet. Low-grade diesel fuel from the main fuel tank is then supplied to the engine, completing the switch from secondary to primary fuel supply. This switching time is within 150ms. Simultaneously, the return fuel valve core is in the state where the third return port is connected to the second return port, allowing fuel to return from the engine to the secondary fuel tank. After a certain delay (ensuring that high-grade diesel fuel in the pipeline returns to the secondary fuel tank), the solenoid valve drives the return fuel valve core to rotate 90°, connecting the third return port to the first return port. The main fuel tank return fuel channel opens, while the secondary fuel tank return fuel channel closes, allowing fuel in the pipeline to return to the main fuel tank. Thus, the switching valve completes one cycle of switching from high-grade to low-grade fuel.

[0047] like Figure 1 As shown, a first oil outlet flange 5 is provided at the oil outlet of the main oil tank 1; a heat exchanger 19 is provided on the first oil outlet flange 5; the first oil outlet flange 5 is connected to the first oil inlet of the fuel reversing valve 3; the heat exchanger 19 is connected to the heating water inlet pipe 14 and the heating water outlet pipe 15; the heat exchanger 19 extends into the main oil tank 1 from the oil outlet of the main oil tank 1.

[0048] The heating inlet pipe 14 is connected to the engine coolant outlet; the heating outlet pipe 15 is connected to the engine coolant inlet; the heating inlet pipe 14 introduces the engine coolant into the heat exchanger 19 on the first oil outlet flange 5, and the hot water flows through the heat exchanger and then back to the engine through the heating outlet pipe 15. When the temperature rises and there is no need to heat the fuel, the valve on the pipeline can be closed to prevent the oil inlet temperature from being too high.

[0049] The heat exchanger 19 is connected to the engine coolant via the heated inlet pipe 14 and the heated outlet pipe 15, allowing the engine coolant to flow into the heat exchanger and exchange heat with the low-grade diesel fuel in the main fuel tank 1. When the engine coolant temperature is high, it can provide energy to heat the low-grade diesel fuel. Normally, the heat from the engine coolant is dissipated into the air through the cooling system and cannot be further utilized. Adding the heat exchanger 19 allows this heat to be utilized, further reducing the operating costs of the bulldozer.

[0050] In some embodiments, the first oil outlet flange 5 is connected to the fuel reversing valve 3 via the first oil inlet pipe 11, and the fuel reversing valve 3 is connected to the return port of the main fuel tank 1 via the first return pipe 10; a second oil outlet flange 4 is provided at the oil outlet of the auxiliary fuel tank 2, and the second oil outlet flange 4 is connected to the fuel reversing valve 3 via the second oil inlet pipe 8, and the fuel reversing valve 3 is connected to the return port of the auxiliary fuel tank 2 via the second return pipe 9.

[0051] The engine return port is connected to the third return port of the fuel reversing valve 3 via the engine return pipe 13.

[0052] The fuel reversing valve 3's reversing valve outlet is connected to the engine's fuel inlet via the engine fuel inlet pipe 12. A heating device is installed on the engine oil inlet pipe 12 to heat the engine oil inlet pipe.

[0053] The heating device can be a resistance wire, which will emit heat when energized, and can heat the engine fuel inlet pipe 12, thereby heating the fuel in the engine fuel inlet pipe 12 and preventing the fuel from condensing in the engine fuel inlet pipe 12.

[0054] The heating device is controlled in conjunction with the state changes of the fuel reversing valve 3. The heating device activates when the first inlet of the fuel reversing valve connects to the outlet, and deactivates when the second inlet connects to the outlet. Specifically, when switching to low-octane fuel for engine supply, the heating device begins heating the engine fuel inlet pipe 12; when switching to high-octane fuel, the heating device stops heating the engine fuel inlet pipe 12. When the driver presses the switch, the fuel reversing valve switches to the main fuel tank (large chamber) fuel supply channel, and simultaneously, the relay connected to the heating device engages, starting the heating device.

[0055] The fuel reversing valve and relay are directly linked. The negative terminal of the heating device is connected in parallel with the main fuel tank control line of the fuel reversing valve, and the positive terminal of the heating device is connected to the power supply through an independent fuse. This ensures that when switching to low-grade diesel fuel from the large fuel tank to supply the engine, the heating circuit of the heating device is activated, and the control signals of the heating device and the fuel reversing valve flow as follows: Figure 5 As shown, the circuit framework used is as follows: Figure 6 As shown.

[0056] in, Figure 5 The button in the middle is a toggle switch, valve core 1 is the oil inlet channel valve core, and valve core 2 is the oil return channel valve core.

[0057] The usage process of the fuel supply system for bulldozers in cold regions proposed in this embodiment of the invention includes: When the engine is started in low-temperature conditions, the auxiliary fuel tank supplies high-grade diesel fuel to the engine. The diesel fuel route at this time is: Auxiliary fuel tank 2 → Second outlet flange 4 → Second inlet pipe 8 → Fuel reversing valve 3 → Engine inlet pipe 12 → Engine → Engine return pipe 13 → Fuel reversing valve 3 → Second return pipe 9 → Auxiliary fuel tank 2. Once the engine coolant temperature rises and stabilizes, the supply of low-grade diesel fuel to the engine changes to the main fuel tank. The diesel fuel route at this time is: Main fuel tank 1 → First outlet flange 5 → First inlet pipe 11 → Fuel reversing valve 3 → Engine Engine inlet pipe 12 → Engine → Engine return pipe 13 → Fuel reversing valve 3 → Second return pipe 9 → Auxiliary fuel tank 2; After all the high-grade diesel fuel in the engine and return pipes returns to the auxiliary fuel tank 2, low-grade diesel fuel continues to be supplied to the engine through the main fuel tank, but the return fuel is changed to return to the main fuel tank. At this time, the diesel fuel route is: Main fuel tank 1 → First outlet flange 5 → First inlet pipe 11 → Fuel reversing valve 3 → Engine inlet pipe 12 → Engine → Engine return pipe 13 → Fuel reversing valve 3 → First return pipe 10 → Main fuel tank 1.

[0058] The driver can operate a switch to switch between supplying low-grade and high-grade diesel fuel to the engine. When the switch is pressed, the solenoid valve of the fuel reversing valve is energized, connecting the first inlet to the outlet and the third return port to the second return port. When low-grade diesel fuel is supplied to the engine, the heating device activates, heating the engine fuel inlet pipe 12 to synchronize low-grade fuel supply and heating. After a certain period, the return fuel supply switches to the new fuel type. When the switch is operated again, the solenoid valve is de-energized, connecting the second inlet to the outlet and the third return port to the second return port. Simultaneously, the heating pipe is de-energized, switching to high-grade fuel supply, and the heating device stops heating.

[0059] In this embodiment of the invention, the bulldozer's fuel tank is replaced with a large main fuel tank and a small auxiliary fuel tank. An electronically controlled fuel switching valve is added to the fuel supply line. When the engine starts at low temperatures, it operates with high-grade diesel fuel. After the engine coolant temperature rises and stabilizes, the driver switches to low-grade diesel fuel for the engine via a switch in the cab. At the same time, the heating device starts heating the engine fuel inlet pipe to prevent diesel fuel from condensing in the engine fuel inlet pipe. The valve on the heating inlet pipe is manually controlled and is kept open when the temperature is low. The low-grade diesel fuel in the main fuel tank is heated through a heat exchanger to ensure that the low-grade diesel fuel does not condense in the fuel tank.

[0060] In this way, bulldozers no longer need to use expensive high-octane diesel fuel continuously in cold environments. They only need to use high-octane diesel when the engine is warm, and low-octane diesel in other situations, effectively reducing diesel costs for owners operating their vehicles in cold conditions. Furthermore, by setting a switch, when the bulldozer is in a normal or high-temperature environment, the switch can be operated to directly supply fuel to the engine using low-octane diesel, further saving on the consumption of high-octane diesel and reducing the operating costs of the bulldozer.

[0061] This invention also proposes a fuel supply method for a fuel supply system for bulldozers in cold regions, comprising: When the engine starts, the fuel reversing valve is switched to the state where the second inlet port is connected to the reversing valve outlet port and the third return port is connected to the second return port, so as to provide high-grade diesel fuel to the engine and return the high-grade diesel fuel in the engine to the auxiliary fuel tank. After the engine starts for the first set time, the fuel reversing valve is switched to the state where the first fuel inlet is connected to the fuel outlet of the reversing valve and the third fuel return port is connected to the second fuel return port, so as to provide low grade diesel fuel to the engine and return the high grade diesel fuel in the engine to the auxiliary fuel tank. After the engine starts for the second set time, the fuel reversing valve is switched to a state where the first fuel inlet is connected to the fuel outlet of the reversing valve, and the third fuel return port is connected to the first fuel return port, so as to provide low-grade diesel fuel to the engine and return the low-grade diesel fuel in the engine to the main fuel tank.

[0062] Furthermore, the heating device on the engine fuel inlet pipe is activated when the first fuel inlet of the fuel reversing valve is connected to the fuel outlet of the reversing valve; the heating device on the engine fuel inlet pipe is deactivated when the second fuel inlet of the fuel reversing valve is connected to the fuel outlet of the reversing valve.

[0063] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A cold weather bulldozer fuel supply system characterized by, The application relates to a fuel switching valve and a fuel switching method. The fuel switching valve comprises a main oil tank, a secondary oil tank and a fuel switching valve; the main oil tank is filled with low-grade diesel oil, and the secondary oil tank is filled with high-grade diesel oil; a first oil inlet, a second oil inlet, a first oil return, a second oil return, a switching valve oil outlet and a third oil return are arranged on the fuel switching valve; an oil inlet of the engine is communicated with the switching valve oil outlet of the fuel switching valve; an oil return of the engine is communicated with the third oil return of the fuel switching valve; an oil outlet of the main oil tank is communicated with the first oil inlet of the fuel switching valve; an oil return of the main oil tank is communicated with the first oil return of the fuel switching valve; an oil outlet of the secondary oil tank is communicated with the second oil inlet of the fuel switching valve; and an oil return of the secondary oil tank is communicated with the second oil return of the fuel switching valve. When the engine starts, the fuel switching valve is in a state of being connected between the second oil inlet and the switching valve oil outlet and being connected between the third oil return and the second oil return. After the engine starts for a first set time, the fuel switching valve is in a state of being connected between the first oil inlet and the switching valve oil outlet and being connected between the third oil return and the second oil return. After the engine starts for a second set time, the fuel switching valve is in a state of being connected between the first oil inlet and the switching valve oil outlet and being connected between the third oil return and the first oil return. An oil outlet flange is arranged on the oil outlet of the main oil tank; a heat exchanger is arranged on the oil outlet flange; the oil outlet flange is communicated with the first oil inlet of the fuel switching valve; the heat exchanger is communicated with a heating water inlet pipe and a heating water outlet pipe; and the heat exchanger extends into the main oil tank from the oil outlet of the main oil tank. The heating water inlet pipe is communicated with an engine cooling liquid outlet; and the heating water outlet pipe is communicated with an engine cooling liquid inlet.

2. A cold weather bulldozer fuel supply system as set forth in Claim 1 wherein, The switching valve oil outlet of the fuel switching valve is communicated with the oil inlet of the engine through an engine oil inlet pipe.

3. A cold weather bulldozer fuel supply system as set forth in Claim 2 wherein, A heating device is arranged on the engine oil inlet pipe, and the heating device is used for heating the engine oil inlet pipe.

4. A cold weather bulldozer fuel supply system as set forth in Claim 1 wherein, The heating device is started when the first oil inlet of the fuel switching valve is connected with the switching valve oil outlet, and the heating device is stopped when the second oil inlet of the fuel switching valve is connected with the switching valve oil outlet. A drain port is arranged on the main oil tank and the secondary oil tank.

5. A cold weather bulldozer fuel supply system as set forth in Claim 4 wherein, The volume of the main oil tank is larger than that of the secondary oil tank.

6. A cold weather bulldozer fuel supply system as set forth in Claim 1 wherein, The fuel switching valve is connected with a switching switch; and the switching switch is used for controlling the state switching of the fuel switching valve.

7. A cold weather bulldozer fuel supply system as set forth in Claim 1 wherein, The method comprises the following steps:

8. A cold weather bulldozer fuel supply system as set forth in Claim 1 wherein, When the engine starts, the fuel switching valve is switched to a state of being connected between the second oil inlet and the switching valve oil outlet and being connected between the third oil return and the second oil return, so as to provide high-grade diesel oil for the engine and return the high-grade diesel oil in the engine to the secondary oil tank; 9. A method of fuel supply for a fuel supply system of a bulldozer in a cold region according to any one of claims 1 to 8, characterized in that, After the engine starts for a first set time, the fuel switching valve is switched to a state of being connected between the first oil inlet and the switching valve oil outlet and being connected between the third oil return and the second oil return, so as to provide low-grade diesel oil for the engine and return the high-grade diesel oil in the engine to the secondary oil tank; After the engine starts for a second set time, the fuel switching valve is switched to a state of being connected between the first oil inlet and the switching valve oil outlet and being connected between the third oil return and the first oil return, so as to provide low-grade diesel oil for the engine and return the low-grade diesel oil in the engine to the main oil tank. The heating device on the engine oil inlet pipe is started when the first oil inlet of the fuel switching valve is connected with the switching valve oil outlet, and the heating device on the engine oil inlet pipe is stopped when the second oil inlet of the fuel switching valve is connected with the switching valve oil outlet. ​ 10. The fuel supply method according to claim 9, characterized by ​

Images