High-horsepower engine fuel system for engineering machinery and starting method of high-horsepower engine fuel system

Abstract

The invention discloses a high-horsepower engine fuel oil system for engineering machinery, which comprises a fuel oil tank assembly, an oil suction selection valve, an oil-water separator, an oil return selection valve, a thermostat, a fuel oil cooler, a low-pressure fuel oil pump, a fuel oil fine filter, a high-pressure fuel injection pump, an engine and a fuel oil heater. Quick exhaust of a fuel oil system is achieved, return oil of an engine is connected to an outlet of the oil-water separator, the oil temperature is quickly increased, and the time for the engine to reach the optimal working temperature is shortened; through the design of the main oil tank, the auxiliary oil tank and the main oil tank preheating, under the extremely cold condition, after medium-low-grade oil in the auxiliary oil tank is used and engine cooling liquid is heated, conventional-grade oil in the main oil tank is preheated, when the oil in the main oil tank meets the engine oil suction condition, an oil way of the main oil tank is switched to conduct fuel oil circulation, and mixing of the oil in the double oil tanks is effectively avoided; the use cost of fuel oil is greatly saved, and energy consumption is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of engineering machinery, and in particular relates to a fuel system of a high-horsepower engine for engineering machinery and a starting method thereof. Background Art

[0002] For all diesel engines used in loaders and even construction machinery, air will be mixed into the fuel system after the first installation, replacement of new oil-water separator filter, replacement of fuel system pipes, maintenance, etc. Generally, engine manufacturers will require automatic or manual exhaust, and after replacing the new oil-water separator filter, require manual filling of the oil-water separator with fuel to facilitate starting of the engine system.

[0003] For small and medium horsepower engines, by pressing the manual pump on the oil-water separator or the added electronic pump, the air inside the pipeline can be emptied in a shorter time, so that the entire fuel system is filled with oil, and the engine can be started smoothly by starting the key switch.

[0004] However, for high-horsepower or ultra-high-horsepower engine fuel systems, the pipeline resistance is large and manual oil pumping is impossible. The oil-water separator is generally equipped with an electronic pump for oil filling. After the entire machine is assembled and the engine is started for the first time, there is air in the pipeline and there is no oil. Therefore, the oil pumping pressure of the electronic pump is still relatively small compared to the pipeline resistance, causing difficulty in starting the engine. At the moment of engine starting, the starter motor consumes more power from the on-board battery and generates more heat. The engine manufacturer requires that the starter motor cannot be started multiple times in succession.

[0005] Large loaders and bulldozers are mostly used in Mongolia, Russia, Northeast China, Inner Mongolia and other places. The ambient temperature is relatively low, and high-grade diesel must be used to meet the starting requirements of the engine fuel system, resulting in excessively high use costs for the entire machine. In addition, the return oil pipe of the conventional fuel system is directly connected to the fuel tank. The fuel tank of large machinery is too large, and the diesel temperature is relatively low, resulting in reduced engine combustion efficiency, increased mechanical wear, poor lubrication effect, and affected starting performance. Summary of the invention

[0006] In view of the problems existing in the above-mentioned prior art, the present invention provides a high-horsepower engine fuel system for construction machinery and a starting method thereof, which can realize the rapid exhaust and starting of the high-horsepower engine fuel system; for cold areas, the temperature of the engine fuel system can be accelerated to make the power system reach the optimal operating temperature as soon as possible; by using dual fuel tank switching, the cost of using the whole machine is reduced.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a fuel tank assembly, an oil suction selection valve, an oil-water separator, an oil return selection valve, a thermostat, a fuel cooler, a low-pressure fuel pump, a fuel fine filter, a high-pressure fuel injection pump, an engine, and a fuel heater. The fuel tank assembly is provided with a main fuel tank and a sub-fuel tank. The oil outlets of the main fuel tank and the sub-fuel tank are connected to the oil inlet of the oil suction selection valve through a pipeline. The oil outlet of the oil suction selection valve is connected to the oil-water separator, the oil return selection valve, the thermostat, the fuel cooler, the low-pressure fuel pump, the fuel fine filter, the high-pressure fuel injection pump, and the high-pressure fuel pipeline of the common rail in the engine in sequence through a pipeline. The oil outlet of the engine is connected to the pipeline between the oil-water separator and the oil return selection valve through a pipeline. The other two oil outlets of the oil return selection valve are respectively connected to the oil return ports of the main fuel tank and the sub-fuel tank through pipelines. The branch port of the thermostat is connected to the oil outlet of the fuel cooler through a pipeline. The oil-water separator is an oil-water separator with an electronic pump.

[0008] The main fuel tank and the auxiliary fuel tank are connected to the two oil inlets of the oil suction selection valve through the oil suction pipe respectively, and the oil outlet of the oil suction selection valve is connected to the oil-water separator inlet; the oil outlet of the oil-water separator is connected to the inlet of the fuel circuit selection valve, and the three oil outlets of the fuel circuit selection valve are connected to the main water tank return oil port, the auxiliary water tank return oil port, and the thermostatic valve oil inlet through pipelines respectively, and the two oil outlets of the thermostatic valve are connected to the oil inlet and oil outlet of the fuel cooler through pipelines respectively, and the oil outlet of the fuel cooler is connected to the oil inlet of the low-pressure fuel pump through a pipeline, and the oil outlet of the low-pressure fuel pump is connected to the high-pressure fuel pump after passing through the fuel fine filter through a pipeline, and the oil outlet of the high-pressure fuel pump is connected to the high-pressure fuel pipeline of the engine common rail, and is sprayed out through the injector on the high-pressure fuel pipeline; the remaining fuel is connected to the oil outlet of the oil-water separator through a pipeline.

[0009] Furthermore, a fuel heater is provided inside the main fuel tank, and the fuel heater is connected to the engine cooling system through a pipeline.

[0010] Furthermore, the capacity of the main fuel tank is greater than the capacity of the auxiliary fuel tank.

[0011] Furthermore, for high-altitude and cold areas, the main fuel tank and auxiliary fuel tank can store different types of fuel products. The main fuel tank stores conventional grades of fuel, and the auxiliary fuel tank stores high-grade fuel, ensuring that the oil does not wax at ambient temperature.

[0012] A method for starting a fuel system of a high-horsepower engine for construction machinery. When the engine fuel system needs to be exhausted, exhaust is performed in two modes, namely, main fuel tank-oil-water separator-main fuel tank or auxiliary fuel tank-oil-water separator-auxiliary fuel tank, through an oil suction selection valve and an oil return selection valve according to the ambient temperature; the engine is started after the exhaust is completed.

[0013] Furthermore, when the ambient temperature is low or the whole machine has not been started for a long time, connect the oil suction selection valve to the auxiliary oil tank, and connect the fuel circuit selection valve to the oil return port of the auxiliary oil tank; this oil return pipeline is shorter, the fuel grade is higher, and the resistance of the entire fuel circuit is the smallest. Turn on the key switch to the power-on state, the electric pump of the oil-water separator starts to run, and the air in the entire fuel pipeline is quickly emptied; After the set time is reached, the electric pump of the oil-water separator stops working, the fuel circuit selection valve is manually / automatically adjusted to the interface connected to the fuel cooler, the key switch is turned to the engine start state, the starter motor drives the engine to start, and the low-pressure fuel pump drives the fuel to suck the fuel from the auxiliary tank, and passes through the oil-water separation, thermostat, and fuel fine filter to the fuel high-pressure pump. The fuel high-pressure pump pressurizes the oil and sprays it out through the high-pressure fuel pipeline inside the engine to the injector. The unburned pressurized and heated oil returns to the pipeline at the oil outlet of the oil-water separator through the pipeline, and another fuel circulation process is carried out; this loop effectively increases the speed of oil temperature rise in the entire fuel pipeline; after the engine is quickly started, as the heat emitted by the combustion of fuel inside the engine, the coolant temperature inside the engine gradually rises, and the lubricating oil gradually reaches the optimal working temperature as the temperature rises; The heated engine coolant enters the main fuel tank through the pipeline, and the internal heater preheats the main fuel tank. The cooled coolant returns to the water pump inlet of the engine cooling system. The oil in the main fuel tank is heated by the coolant, and after a period of time, it resumes the flowing state. At this time, the oil inlet selection valve is manually / automatically switched to the main fuel tank, and the oil is burned through the oil-water separator, thermostat, low-pressure fuel pump, fuel fine filter, high-pressure fuel pump, injector, and engine body. The return oil pipeline is connected to the oil outlet of the oil-water separator and merges with the oil sucked from the fuel tank to enter the next cycle.

[0014] Furthermore, when the ambient temperature is high, only the main fuel tank pipeline is used. When the fuel system needs to be vented, the suction selector valve is connected to the main fuel tank suction port, the main fuel tank is filled with conventional oil, the key switch is turned on, the electric pump of the oil-water separator starts to run, and the air in the entire fuel pipeline is quickly emptied; After the set time is reached, the electric pump of the oil-water separator stops working, the fuel circuit selection valve is manually / automatically adjusted to the interface connected to the fuel cooler, the key switch is turned to the engine start state, the starter motor drives the engine to start, and the low-pressure fuel pump drives the fuel to suck the fuel from the main tank, and passes through the oil-water separation, thermostat, and fuel fine filter to the fuel high-pressure pump. The fuel high-pressure pump pressurizes the oil and sprays it out through the high-pressure fuel pipeline inside the engine to the injector. The unburned pressurized and heated fuel returns to the pipeline of the oil outlet of the oil-water separator through the pipeline, and another fuel circulation process is carried out; this circuit effectively increases the speed of oil temperature rise in the entire fuel pipeline; after the engine is quickly started, with the heat emitted by the combustion of fuel inside the engine, the coolant temperature inside the engine gradually rises, and the lubricating oil gradually reaches the optimal working viscosity state as the temperature rises; When the oil temperature in the fuel system is too high and reaches the opening temperature of the thermostat valve, the thermostat valve opens, and the oil is cooled by the fuel cooler and flows into the low-pressure fuel pump, and then passes through the fuel fine filter and the high-pressure fuel pump to the engine. The unburned pressurized and heated fuel is returned to the oil outlet of the oil-water separator through the pipeline.

[0015] The beneficial effects of the present invention are as follows: by manually / automatically adjusting the oil tank oil suction selection valve and the oil return selection valve, the rapid exhaust of the fuel system of a high-horsepower engine for engineering machinery is achieved, and by connecting the oil return port to the oil-water separator outlet, the oil temperature is quickly increased, greatly shortening the time it takes for the engine to reach the optimal operating temperature; through the design of the main and auxiliary double oil tanks and the main oil tank preheater, it is possible to use low-grade diesel in the auxiliary oil tank and the main oil circuit under extremely cold conditions, and after the engine coolant temperature rises, preheat the conventional grade diesel in the main oil tank, and when the oil in the main oil tank meets the engine oil suction conditions, switch to the main oil tank oil circuit for fuel circulation, and effectively avoid mixing of the oil products in the double tanks, greatly saving the cost of fuel use and saving energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below through the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0019] like Figure 1 As shown, a fuel system of a high-horsepower engine for construction machinery includes: a fuel tank assembly 1, an oil suction selection valve 3, an oil-water separator 4, an oil return selection valve 5, a thermostat 6, a fuel cooler 7, a low-pressure fuel pump 8, a fuel fine filter 9, a high-pressure fuel injection pump 10, an engine 11, and a fuel heater 12. A main fuel tank 101 and a sub-fuel tank 102 are provided in the fuel tank assembly 1. The main fuel tank 101 is connected to the oil suction selection valve 3 through a main fuel tank suction pipe, and the sub-fuel tank 102 is connected to the oil suction selection valve 3 through a sub-fuel tank suction pipe; the oil outlet of the oil suction selection valve 3 is connected to the oil inlet of the oil-water separator 4, and the oil outlet of the oil-water separator 4 is connected to the oil inlet of the fuel circuit selection valve 5. The three parts of the fuel circuit selection valve 5 are connected to the oil inlet of the fuel circuit selection valve 5. One of the oil outlets is connected to the oil return port of the auxiliary fuel tank 102, the other oil outlet is connected to the oil inlet of the thermostat 6, and the other oil outlet is connected to the oil return port of the main fuel tank 101; one oil outlet of the thermostat 6 is connected to the fuel cooler 7, and the other oil outlet is connected to the fuel low-pressure pump 8 or the oil outlet of the fuel cooler 7 or the pipeline between the fuel low-pressure pump 8 and the fuel cooler 7; the fuel cooler 7 is connected to the fuel low-pressure pump 8; after the fuel passes through the fuel low-pressure pump 8, it passes through the fuel fine filter 9 and flows into the high-pressure fuel pump 10 to the high-pressure fuel pipeline of the common rail of the engine 11, and is sprayed out through the injector on the high-pressure fuel pipeline to carry out the combustion process; the remaining fuel is connected to the oil outlet of the oil-water separator 4 through a pipeline.

[0020] The oil-water separator 4 integrates an electric pump 401; the fuel tank assembly 1 is divided into a main fuel tank 101 and an auxiliary fuel tank 102 by a partition, and the main fuel tank 101 has a larger volume, and the auxiliary fuel tank 102 has a smaller volume. A fuel heater 12 is installed inside the main fuel tank 101.

[0021] Mainly for high-cold areas, the main fuel tank 101 and the auxiliary fuel tank 102 store oils of different brands; the main fuel tank 101 stores oils of one brand lower than that stored in the auxiliary fuel tank 102. For example, the main fuel tank 101 stores oil of 0 or -10# diesel, and the auxiliary fuel tank 102 stores oil of -35# diesel. The auxiliary fuel tank 102 must ensure that it does not wax at ambient temperature.

[0022] A method for starting a fuel system of a high-horsepower engine for construction machinery: When the machine is started for the first time after installation or when the machine has not been used for a long time or when the pipelines and components of the fuel system are repaired and maintained, air will be mixed into the fuel system. At this time, the oil suction selection valve 3 is connected to the auxiliary fuel tank 102, and the fuel circuit selection valve 5 is connected to the return port of the auxiliary fuel tank 102; this fuel return pipeline II is shorter, the fuel grade is higher, and it has good fluidity, and the resistance of the entire fuel circuit is minimized; start the key switch of the whole machine to the power-on state, the electric pump 401 of the oil-water separator 4 starts to run, and the air in the entire fuel pipeline can be quickly emptied; after the set time T1 is reached, the electric pump 401 stops working; Manually / automatically adjust the fuel circuit selection valve 5 to the main fuel pipeline I, turn on the key switch to the engine start state, start the motor to drive the engine to start, and the low-pressure fuel pump 8 works to drive the fuel system to absorb oil from the auxiliary fuel tank 102. At this time, the oil temperature is low, and the thermostat 6 is in a closed state. The oil passes through the oil-water separator 4, the thermostat 6, the low-pressure fuel pump 8, and the fuel fine filter 9 to the fuel high-pressure pump 9. The fuel high-pressure pump 9 pressurizes the oil. The pressurized oil passes through the high-pressure fuel pipeline inside the engine 11 to the injector and is sprayed out to carry out the combustion process; after pressurization and heating The excess oil after the start is returned to the oil outlet of the oil-water separator 4 through the fuel return pipeline, merges with the new oil sucked from the fuel tank and undergoes another fuel circulation process; this fuel circuit effectively improves the oil temperature rise speed of the entire fuel pipeline; after the engine is quickly started, as the heat emitted by the combustion of the fuel inside the engine, the coolant temperature inside the engine gradually increases, and as the temperature of the lubricating oil increases, the engine quickly reaches the nearest working state; the return pipe of the main oil circuit I is connected to the oil outlet of the oil-water separator 4, which can effectively avoid the mixing of two different grades of oil products in the main tank 101 and the auxiliary tank 102.

[0023] The heated engine coolant enters the main tank 101 preheating pipeline into the main tank internal heater 12 to preheat the main tank 101, and the cold water returns to the interface at the engine water pump inlet. The conventional brand of diesel in the main tank 101 is heated by the coolant and can resume flowing after time T2.

[0024] After the oil in the main fuel tank 101 resumes flowing state, the oil suction selection valve 3 is manually / automatically switched to the oil suction port of the main fuel tank 101, and the oil flows into the combustion chamber of the engine 11 through the oil-water separator 4, the thermostat 6, the low-pressure fuel pump 8, the fuel fine filter 9, and the high-pressure fuel pump 10 for combustion. The excess oil after pressurization and heating is returned to the oil outlet of the oil-water separator 4 through the fuel return pipeline, and merges with the new oil sucked from the tank to perform another fuel circulation process.

[0025] It can effectively solve the waxing problem of low-grade diesel in low-temperature environment, and use the engine 1 coolant and heater 12 to effectively preheat the oil in the main tank 101, which can not only save the cost of adding all high-grade diesel, but also reduce the loss of electric heating oil to the battery, greatly saving the cost of using the whole machine.

[0026] When the ambient temperature is high, the entire fuel system only uses the main tank fuel line: The main oil tank 101 is filled with conventional grade oil; When the fuel system needs to be vented, the oil suction selection valve 3 is connected to the oil suction port of the main fuel tank 101, and the fuel circuit selection valve 5 is connected to the oil return port of the main fuel tank 101; this fuel return pipeline II is shorter, turn on the key switch to the power-on state, the electric pump 401 of the oil-water separator 4 starts to run, and the air in the entire fuel pipeline can be quickly emptied; after the set time T3 is reached, the electric pump 401 stops working.

[0027] Manually / automatically adjust the fuel circuit selection valve 5 to the main fuel pipeline I, turn on the key switch to the engine start state, start the motor to run, drive the engine to start, and the low-pressure fuel pump 8 works, driving the fuel system to suck oil from the auxiliary fuel tank 102. At this time, the oil temperature is low, and the thermostat 6 is in a closed state. The oil passes through the oil-water separator 4, the thermostat 6, the low-pressure fuel pump 8, and the fuel fine filter 9 to the fuel high-pressure pump 9. The fuel high-pressure pump 9 pressurizes the oil. The pressurized oil passes through the high-pressure fuel pipeline inside the engine 11 to the injector and is sprayed out to carry out the combustion process; the excess oil after pressurization and heating is returned to the oil outlet of the oil-water separator 4 through the fuel return pipeline, and merges with the new oil sucked from the tank to carry out another fuel circulation process; this fuel circuit effectively increases the oil temperature rise speed of the entire fuel pipeline; after the engine is quickly started, with the heat emitted by the combustion of the fuel inside the engine, the coolant temperature inside the engine gradually rises, and the lubricating oil rises with the temperature, and the engine quickly reaches the nearest working state. When the oil temperature of the fuel system continues to rise to a certain temperature, reaching the opening temperature of the thermostat 6 valve, the valve opens, and the oil is cooled by the cooler 7 and flows into the low-pressure fuel pump 8, and then flows through the fuel fine filter 9 and the high-pressure fuel pump 10 to the engine. The unburned excess oil returns to the oil outlet of the oil-water separator and merges with the new oil in the fuel tank for a cycle.

[0028] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-horsepower engine fuel system for construction machinery, characterized in that: include: A fuel tank assembly, an oil suction selection valve, an oil-water separator, an oil return selection valve, a thermostat, a fuel cooler, a low-pressure fuel pump, a fuel fine filter, a high-pressure fuel injection pump, an engine, and a fuel heater. A main fuel tank and a sub-tank are provided in the fuel tank assembly. The oil outlets of the main fuel tank and the sub-tank are connected to the oil inlet of the oil suction selection valve through a pipeline. The oil outlet of the oil suction selection valve is connected to the oil-water separator, the oil return selection valve, the thermostat, the fuel cooler, the low-pressure fuel pump, the fuel fine filter, the high-pressure fuel injection pump, and the high-pressure fuel pipeline of the common rail in the engine through a pipeline in sequence. The oil outlet of the engine is connected to the pipeline between the oil-water separator and the oil return selection valve through a pipeline. The other two oil outlets of the oil return selection valve are respectively connected to the oil return ports of the main fuel tank and the sub-tank through pipelines. The branch port of the thermostat is connected to the oil outlet of the fuel cooler through a pipeline. The oil-water separator is an oil-water separator with an electronic pump.

2. A high-horsepower engine fuel system for construction machinery according to claim 1, characterized in that: A fuel heater is arranged inside the main fuel tank, and the fuel heater is connected to the engine cooling system through a pipeline.

3. A high-horsepower engine fuel system for construction machinery according to claim 1, characterized in that: The volume of the main oil tank is greater than the volume of the auxiliary oil tank.

4. A high-horsepower engine fuel system for construction machinery according to claim 2, characterized in that: For high-altitude and cold areas, the main fuel tank and auxiliary fuel tank can store different types of fuel products. The main fuel tank stores conventional grades of fuel, and the auxiliary fuel tank stores high-grade fuel to ensure that the oil does not wax at ambient temperature.

5. The method for starting a fuel system of a high-horsepower engine for construction machinery according to claim 4, characterized in that: When the engine fuel system needs to be exhausted, the exhaust is carried out in two modes, namely, main fuel tank-oil-water separator-main fuel tank or auxiliary fuel tank-oil-water separator-auxiliary fuel tank, through the oil suction selection valve and the oil return selection valve according to the ambient temperature; the engine is started after the exhaust is completed.

6. The method for starting a fuel system of a high-horsepower engine for construction machinery according to claim 5, characterized in that: When the ambient temperature is low or the whole machine has not been started for a long time, connect the oil suction selection valve to the auxiliary oil tank, and connect the fuel circuit selection valve to the oil return port of the auxiliary oil tank; this oil return pipeline is short, the fuel grade is high, and the resistance of the entire fuel circuit is minimal. Turn on the key switch to the power-on state, the electric pump of the oil-water separator starts to run, and the air in the entire fuel pipeline is quickly emptied; After the set time is reached, the electric pump of the oil-water separator stops working, the fuel circuit selection valve is manually / automatically adjusted to the interface connected to the fuel cooler, the key switch is turned to the engine start state, the starter motor drives the engine to start, and the low-pressure fuel pump drives the fuel to suck the fuel from the auxiliary tank, through the oil-water separator, thermostat, fuel fine filter to the fuel high-pressure pump, the fuel high-pressure pump pressurizes the oil, and sprays it out through the high-pressure fuel pipeline inside the engine to the injector. The unburned pressurized and heated oil returns to the pipeline of the oil outlet of the oil-water separator through the pipeline, and another fuel circulation process is carried out; this loop effectively increases the speed of oil temperature rise in the entire fuel pipeline; after the engine is quickly started, with the heat emitted by the combustion of fuel inside the engine, the coolant temperature inside the engine gradually rises, and the lubricating oil gradually reaches the optimal working temperature as the temperature rises; The heated engine coolant enters the main fuel tank through the pipeline, and the internal heater preheats the main fuel tank. The cooled coolant returns to the water pump inlet of the engine cooling system. The oil in the main fuel tank is heated by the coolant, and after a period of time, it resumes the flowing state. At this time, the oil inlet selection valve is manually / automatically switched to the main fuel tank, and the oil is burned through the oil-water separator, thermostat, low-pressure fuel pump, fuel fine filter, high-pressure fuel pump, injector, and engine body. The return oil pipeline is connected to the oil outlet of the oil-water separator and merges with the oil sucked from the fuel tank to enter the next cycle.

7. The method for starting a fuel system of a high-horsepower engine for construction machinery according to claim 5, characterized in that: When the ambient temperature is high, only the main fuel tank pipeline is used. When the fuel system needs to be exhausted, the suction selector valve is connected to the main fuel tank suction port, and the main fuel tank is filled with conventional oil. The key switch is turned on to the power-on state, and the electric pump of the oil-water separator starts to run, and the air in the entire fuel pipeline is quickly exhausted; After the set time is reached, the electric pump of the oil-water separator stops working, the fuel circuit selection valve is manually / automatically adjusted to the interface connected to the fuel cooler, the key switch is turned to the engine start state, the starter motor drives the engine to start, and the low-pressure fuel pump drives the fuel to suck the fuel from the main tank, and passes through the oil-water separation, thermostat, and fuel fine filter to the fuel high-pressure pump. The fuel high-pressure pump pressurizes the oil and sprays it out through the high-pressure fuel pipeline inside the engine to the injector. The unburned pressurized and heated fuel returns to the pipeline of the oil outlet of the oil-water separator through the pipeline, and another fuel circulation process is carried out; this circuit effectively increases the speed of oil temperature rise in the entire fuel pipeline; after the engine is quickly started, with the heat emitted by the combustion of fuel inside the engine, the coolant temperature inside the engine gradually rises, and the lubricating oil gradually reaches the optimal working viscosity state as the temperature rises; When the oil temperature in the fuel system is too high and reaches the opening temperature of the thermostat valve, the thermostat valve opens, and the oil is cooled by the fuel cooler and flows into the low-pressure fuel pump, and then passes through the fuel fine filter and the high-pressure fuel pump to the engine. The unburned pressurized and heated fuel is returned to the oil outlet of the oil-water separator through the pipeline.

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