Oil way for extra-heavy fuel injection pump assembly

Abstract

The utility model discloses an oil way for an extra-heavy fuel injection pump assembly, which is characterized in that the oil way starts from an oil tank, is subjected to double filtration, and is pressurized by a fuel delivery pump to be conveyed to a fuel metering valve; an oil way behind the metering valve is divided into two parts, one part is pressurized by a plunger and then supplied to an oil sprayer, and precise oil spraying is achieved; the other path flows back to the oil tank through the zero-oil-quantity hole, so that leakage is reduced; particularly, a leakage oil guide way is additionally arranged on the oil injection pump body and the plunger sleeve, high-pressure leakage fuel oil possibly generated in the plunger pressurizing process is guided back to an oil tank in time, and the oil supply accuracy and the working efficiency of the oil injection pump are remarkably improved; meanwhile, due to the design, the problem of fuel oil leakage can be conveniently found and treated in time, and stable performance, environmental protection and safety of the extra-heavy fuel injection pump assembly are effectively guaranteed. By means of the innovative oil way design, powerful technical support is provided for efficient, accurate and safe operation of the extra-heavy oil injection pump, and the oil way structure has remarkable practical value and environmental protection significance.

Description

Technical Field

[0001] This utility model belongs to the field of oil circuit technology for fuel injection pump assembly, and particularly relates to an oil circuit for a heavy-duty fuel injection pump assembly. Background Technology

[0002] With increasingly stringent emission regulations, the requirements for fuel injection systems in compression-ignition internal combustion engines are constantly increasing. Not only must the fuel system provide high-pressure fuel, but it also needs to maintain stable pressure during operation to ensure precise fuel injection. In summary, the demands on fuel systems in internal combustion engines are becoming increasingly stringent, primarily in the following aspects:

[0003] High injection pressure: The system injection pressure must reach or exceed 220 MPa;

[0004] Precision fuel delivery: precise timing and metered fuel injection;

[0005] High efficiency: High fuel supply efficiency and low energy consumption;

[0006] Currently, internal combustion engine fuel systems use the rotation of the engine crankshaft to transmit power to the fuel pump shaft in the fuel system via gear transmission. The internal structure of the fuel pump then converts the rotational motion of the shaft into the repetitive motion of the plunger, thereby realizing the fuel pump's suction and pressure processes.

[0007] Fuel is pressurized by the fuel pump and supplied to the energy storage device for injection by the injection device.

[0008] The hydraulic principle of the current fuel injection pump assembly is shown in the attached figure. Figure 1 ;

[0009] ① Fuel tank → filter → fuel pump → filter → fuel metering valve → inlet valve → plunger chamber → outlet valve → common rail → injector;

[0010] ② Fuel metering valve → zero fuel gauge orifice → fuel injection pump return → fuel tank;

[0011] ③Plunger chamber → Before the oil inlet valve;

[0012] When the fuel injection pump is operating, the rotation of the fuel delivery pump generates negative pressure. Atmospheric pressure forces fuel from the fuel tank through the filter into the fuel delivery pump. After pressurizing the fuel, the fuel delivery pump delivers it to the fuel metering valve after pressure regulation by the filter and overflow valve. After the fuel metering valve's flow control, the fuel is divided into two paths: one path is delivered to the inlet valve, pressurized by the plunger, and flows out at the outlet valve, supplying the common rail for fuel injection; the other path returns to the fuel tank through the zero-gauge orifice, this path discharges fuel leaking from the fuel metering valve when it is closed. While the fuel is in the plunger chamber, the plunger assembly pressurizes the fuel. During this pressurization process, the plunger assembly generates high-pressure leakage. Fuel flows through the fuel line to the inlet valve to supply the plunger pressurization process in the next cycle. The high-pressure leakage of fuel during plunger pressurization is at a high temperature. If this fuel is directly led back to the inlet valve, it will raise the fuel temperature before the inlet valve, thereby raising the fuel temperature inside the plunger chamber. This will affect the amount of fuel entering the plunger chamber and exacerbate the high-pressure leakage, thus affecting the working efficiency of the fuel injection pump and the accuracy of fuel supply. In addition, the fuel injection pump outlet and the high-pressure fuel line are rigidly connected. If a failure occurs at the connection and a leak occurs, the fuel will be directly discharged into the air. This will cause pollution and safety hazards to the internal combustion engine operating environment, and at the same time, it will be impossible to identify the failure leak in time. Summary of the Invention

[0013] To address the problems existing in the prior art, this utility model provides an oil circuit for a heavy-duty fuel injection pump assembly. This achieves precise fuel supply from the fuel injection pump, improves its working efficiency, and enables timely identification of leaks and malfunctions, preventing pollution and safety hazards. The oil circuit design incorporates improved layout to achieve the desired objectives.

[0014] This utility model is implemented as follows: an oil circuit for a heavy-duty fuel injection pump assembly includes an inlet branch, which sequentially includes a fuel tank, a first filter, a fuel pump, a second filter, and a fuel metering valve; the fuel metering valve's outlet is divided into two branches, one of which connects the inlet valve to the plunger chamber of the plunger, the outlet of the plunger chamber connects to the outlet valve, the outlet valve connects to the common rail, the common rail connects to the injector, and the other branch connects to the fuel injection pump return pipe via a zero-fuel orifice, the fuel injection pump return pipe connects to the fuel tank; the feature is that the fuel injection pump body is provided with a fuel injection pump leakage guide oil circuit, and the plunger sleeve of the plunger is provided with a plunger sleeve leakage guide oil circuit communicating with the fuel injection pump leakage guide oil circuit, the plunger leakage fuel outlet of the plunger sleeve leakage guide oil circuit being connected to the fuel tank via a guide pipe.

[0015] Preferably, an oil collecting circuit is connected at the connection between the high-pressure oil outlet of the plunger and the high-pressure oil pipe, and the oil collecting circuit is connected to an oil collector.

[0016] Preferably, the oil collector is equipped with a liquid level sensor for detecting the oil level inside the oil collector.

[0017] The advantages and technical effects of this invention are as follows: This invention retains the existing oil circuit system while achieving highly accurate fuel injection pump supply. During the operation of the fuel injection pump, the fuel undergoes multiple filtrations and precise metering before being delivered in two paths. One path, pressurized by the plunger, supplies the fuel to the injector, ensuring the accuracy and stability of fuel injection; the other path flows back to the fuel tank through the zero-flow orifice, effectively discharging leaked fuel from the fuel metering valve when it is closed. Simultaneously, this invention, by adding a fuel injection pump leakage guide path and a plunger sleeve leakage guide path, promptly guides high-pressure leaked fuel generated during the pressurization process of the plunger assembly back to the fuel tank, avoiding the influence of high-temperature fuel on the fuel temperature before the inlet valve, thereby further improving the accuracy of fuel supply and the working efficiency of the fuel injection pump.

[0018] Furthermore, this invention cleverly incorporates an oil collection path and collector, along with a level sensor within the collector. This design not only effectively collects and identifies fuel leaks from the high-pressure fuel line and pump head seals, but also enables real-time monitoring of the fuel level in the collector via the ECU, allowing for timely detection and early warning of fuel leaks. This effectively prevents environmental pollution and safety hazards caused by fuel leaks.

[0019] In summary, this utility model significantly improves the fuel injection pump's fuel supply accuracy and working efficiency through innovative measures such as optimizing the oil circuit design, adding a leakage guide oil circuit, and an oil collection and detection system. At the same time, it enables timely identification and effective prevention of fuel leakage, providing strong protection for the performance improvement and environmental safety of the heavy-duty fuel injection pump assembly. Attached Figure Description

[0020] Figure 1 It is an existing technology oil circuit diagram;

[0021] Figure 2 This is a utility model oil circuit diagram;

[0022] Figure 3 This is a schematic diagram of the structure leading from the high-pressure oil pipe connection to the oil collector;

[0023] Figure 4 This is a schematic diagram of the structure of the fuel injection pump leakage guide oil circuit.

[0024] In the diagram: 1. Fuel tank; 2. First filter; 3. Fuel pump; 4. Second filter; 5. Fuel metering valve; 6. Inlet valve; 7. Injection pump; 8. Plunger; 9. Delivery valve; 10. Common rail; 11. Injector; 12. Zero gauge orifice; 13. Return line; 14. Injection pump leakage guide line; 8-1. Plunger sleeve; 8-2. Plunger sleeve leakage guide line; 15. Guide line; 16. Collection line; 17. Collection device; 18. Level sensor;

[0025] ①-Fuel pump inlet; ②-Fuel pump outlet; ③-High-pressure pump fuel inlet; ④-High-pressure outlet; ⑤-Fuel return port; ⑥-High-pressure fuel leak port; ⑦-Plunger fuel leak port; ⑧-High-pressure limiting valve return valve. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this utility model.

[0027] Please see Figures 2 to 4 A fuel circuit for a heavy-duty fuel injection pump assembly includes an inlet branch, which sequentially includes a fuel tank 1, a first filter 2 connected to the fuel tank via an electronic fuel pump, an outlet of the first filter connected to the fuel pump inlet ① of a fuel pump 3, a fuel pump outlet ② connected to a second filter 4, and a fuel return port of the fuel pump 3 connected to the fuel tank; the outlet of the second filter 4 is connected to the fuel inlet ③ of a high-pressure fuel injection pump, the fuel inlet ③ of the high-pressure fuel injection pump is connected to the high-pressure limiting valve return valve, and a fuel metering valve 5; the outlet of the fuel metering valve is divided into two branches, one of which is the inlet fuel line. Valve 6 connects to the plunger chamber of each plunger 8 in the fuel injection pump 7. The oil outlet of the plunger chamber is connected to the delivery valve 9. The delivery valve is connected to the common rail pipe 10. The common rail pipe is connected to the injector 11. Another branch is connected to the return pipe 13 of the fuel injection pump through the zero-fuel metering orifice 12. The return pipe of the fuel injection pump is connected to the fuel tank 1. The pump body of the fuel injection pump 7 is provided with a fuel injection pump leakage guide oil passage 14. The plunger sleeve 8-1 of the plunger is provided with a plunger sleeve leakage guide oil passage 8-2 that communicates with the fuel injection pump leakage guide oil passage 14. The plunger leakage fuel inlet ⑦ of the plunger sleeve leakage guide oil passage 8-2 is connected to the fuel tank 1 through the guide pipe 15.

[0028] Preferably, an oil collecting passage 16 is connected at the connection between the high-pressure oil outlet ④ of the plunger and the high-pressure oil pipe, and the oil collecting passage is connected to an oil collector 17.

[0029] Preferably, the oil collector is equipped with a liquid level sensor 18 for detecting the oil level in the oil collector.

[0030] Working principle of this utility model:

[0031] When the fuel injection pump is working, the rotation of the fuel pump generates negative pressure. Atmospheric pressure forces fuel from the fuel tank through the filter into the fuel pump. After the fuel pump pressurizes the fuel, it is delivered to the fuel metering valve through the filter and the pressure regulation of the overflow valve. After the fuel metering valve controls the flow, the fuel is divided into two paths. One path is delivered to the inlet valve, pressurized by the plunger, and flows out at the outlet valve to supply fuel to the common rail for fuel injection. The other path returns to the fuel tank through the zero-gauge orifice. This path is for discharging fuel that leaks when the fuel metering valve is closed. When the fuel is in the plunger chamber, the plunger assembly pressurizes the fuel. During the pressurization process, the plunger assembly will generate high-pressure leakage. The leaked fuel is led back to the fuel tank through the fuel line.

[0032] The rigid connection between the fuel injection pump outlet and the high-pressure fuel line is sealed, and a fuel collection path is set up to collect leaked fuel and identify leak failures. The plunger assembly pressurizes and compresses the fuel, which then flows into the pump head after passing through the fuel valve assembly. When a leak occurs at the high-pressure fuel line and the pump head seal, the fuel flows to the fuel collector through the leak path (arrow direction). The ECU determines whether a fuel leak has occurred by monitoring the fuel level in the fuel collector.

[0033] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A fuel circuit for a heavy-duty fuel injection pump assembly, comprising an inlet branch, wherein the inlet branch sequentially includes a fuel tank, a first filter, a fuel pump, a second filter, and a fuel metering valve; the fuel metering valve has an outlet branch divided into two branches, one branch connecting the inlet valve to the plunger chamber of a plunger, the outlet of the plunger chamber connecting to a delivery valve, the delivery valve connecting to a common rail, the common rail connecting to an injector, and the other branch connecting to the fuel injection pump return pipe via a zero-fuel orifice, the fuel injection pump return pipe connecting to the fuel tank; characterized in that: The pump body of the fuel injection pump is provided with a fuel injection pump leakage guide oil passage, and the plunger sleeve of the plunger is provided with a plunger sleeve leakage guide oil passage that communicates with the fuel injection pump leakage guide oil passage. The plunger leakage fuel inlet of the plunger sleeve leakage guide oil passage is connected to the fuel tank through a guide oil pipe.

2. The oil circuit for the heavy-duty fuel injection pump assembly according to claim 1, characterized in that: An oil collecting circuit is connected to the high-pressure oil outlet of the plunger at the connection point with the high-pressure oil pipe, and the oil collecting circuit is connected to an oil collector.

3. The oil circuit for the heavy-duty fuel injection pump assembly according to claim 2, characterized in that: The oil collector is equipped with a liquid level sensor to detect the oil level inside the oil collector.

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