Oil injection system and engine

Abstract

The utility model belongs to the technical field of diesel engines, and discloses an oil injection system and an engine, the oil injection system comprises an oil tank, an oil delivery pump, an electric control pressure release valve, an oil mass metering unit, an oil injection pump and a common rail pipe, an oil outlet of the oil delivery pump is communicated with an oil inlet of the oil mass metering unit and an oil inlet of the electric control pressure release valve in parallel, an oil outlet of the electric control pressure release valve is communicated with the oil tank, an oil outlet of the oil mass metering unit is communicated with an inlet of the oil injection pump, and an outlet of the oil injection pump is communicated with an oil inlet of the common rail pipe. The engine comprises the oil injection system and further comprises an oil injector, an oil inlet of the oil injector is communicated with an oil outlet of the common rail pipe, and an oil outlet of the oil injector is communicated with an oil tank. According to the oil injection system, the electronic control pressure release valve is arranged to replace a traditional mechanical overflow valve, so that the opening degree of the electronic control pressure release valve can be actively adjusted, and the oil return flow and the inlet pressure in front of the oil mass metering unit are flexibly controlled.

Description

Technical Field

[0001] The utility model relates to the technical field of diesel engines, in particular to an oil injection system and an engine. Background Art

[0002] A fuel system in the prior art, such as the patent document with publication number CN111156119A, consists of a gear pump and an oil pump. The fuel enters the oil suction chamber of the gear pump through a coarse filter, is pressurized by the gear pump, and then passes through a fine filter to enter the oil metering unit and the mechanical overflow valve. The oil metering unit and the mechanical overflow valve are parallel structures. When the engine is running, the oil metering unit controls the amount of fuel entering the oil pump according to the engine oil demand, and the excess fuel flows back to the fuel tank through the mechanical overflow valve, thereby maintaining the pressure in front of the oil metering unit stable. When the engine is matched with an electric pump, the fuel is drawn from the fuel tank and passes through a coarse filter, a bypass valve, and a fine filter to fill the oil pipe, and at the same time, the gas in the oil pipe is discharged through the mechanical overflow valve and the zero flow hole.

[0003] However, in the above system, the use of a mechanical overflow valve can only passively affect the opening pressure and flow rate through the structural gap between the valve core and the valve body and the spring stiffness. When the above parameters are determined, the flow characteristics of the overflow valve are determined, and the pressure and return oil flow after the gear pump cannot be actively adjusted, and the fuel supply efficiency of the injection pump under high-load conditions of the engine cannot be improved, and the power coverage of the injection pump is limited. In addition, due to the structure of the mechanical overflow valve, there is always pressure before the inlet of the oil metering unit, resulting in a small part of the fuel entering the plunger cavity of the injection pump through the oil metering unit slide valve structure, causing rail pressure fluctuations. To solve this problem, it is necessary to add a zero flow hole in the oil circuit behind the oil metering unit to guide the fuel that leaks into the oil metering unit back to the fuel tank. However, the zero flow hole returns directly to the fuel tank, which is easily affected by the back pressure of the engine test bench return oil. When the back pressure of the test bench return oil is large, the fuel flows back into the injection pump through the zero flow hole, causing the engine rail pressure to lose control or even the common rail pipe flushing valve failure. Utility Model Content

[0004] The utility model aims to provide an injection system and an engine, by providing an electronically controlled pressure relief valve to replace a traditional mechanical overflow valve, so that the opening of the electronically controlled pressure relief valve can be actively adjusted, and the return oil flow rate and the inlet pressure before the oil metering unit can be flexibly controlled.

[0005] To achieve this purpose, the utility model adopts the following technical solutions:

[0006] A fuel injection system includes a fuel tank, a fuel delivery pump, an electronically controlled pressure relief valve, a fuel metering unit, a fuel injection pump and a common rail pipe; wherein:

[0007] The oil inlet of the oil delivery pump is connected to the oil tank, the oil outlet of the oil delivery pump is connected in parallel with the oil inlet of the oil metering unit and the oil inlet of the electronically controlled pressure relief valve, the oil outlet of the electronically controlled pressure relief valve is connected to the oil tank, the oil outlet of the oil metering unit is connected to the inlet of the fuel injection pump, and the outlet of the fuel injection pump is connected to the oil inlet of the common rail pipe.

[0008] Preferably, a primary filter is further included, wherein the inlet of the primary filter is connected to the oil tank, and the outlet of the primary filter is connected to the oil inlet of the oil pump.

[0009] Preferably, a throttle valve is provided on the connecting pipeline between the outlet of the primary filter element and the oil inlet of the oil pump.

[0010] Preferably, an electric pump is further included, wherein the oil inlet of the electric pump is connected to the oil tank, and the oil outlet of the electric pump is connected to the inlet of the primary filter element.

[0011] Preferably, a secondary filter is further included, the inlet of the secondary filter is connected to the oil outlet of the oil pump, and the outlet of the secondary filter is connected in parallel to the oil inlet of the oil metering unit and the oil inlet of the electronically controlled pressure relief valve.

[0012] Preferably, an overpressure protection valve is further included, and an overpressure protection pipe is provided between the oil inlet and the oil outlet of the oil pump, and the overpressure protection valve is arranged on the overpressure protection pipe. The overpressure protection valve is configured to unidirectionally conduct the overpressure protection pipe from the oil outlet to the oil inlet of the oil pump.

[0013] Preferably, a bypass valve is further included, a bypass pipe is provided between the oil inlet and the oil outlet of the oil pump, the bypass valve is arranged on the bypass pipe, and the bypass valve is configured to unidirectionally guide the bypass pipe from the oil inlet to the oil outlet of the oil pump.

[0014] Preferably, a pressure-limiting valve is further included. A pressure-limiting pipe is provided between the common rail pipe and the fuel tank. The pressure-limiting valve is arranged on the pressure-limiting pipe. The pressure-limiting valve is configured to unidirectionally conduct the pressure-limiting pipe from the common rail pipe to the fuel tank.

[0015] Preferably, a rail pressure sensor is provided on the common rail pipe.

[0016] An engine comprises the fuel injection system described in any one of the above, and further comprises a fuel injector, wherein the fuel inlet of the fuel injector is connected to the fuel outlet of the common rail pipe.

[0017] Beneficial effects:

[0018] The fuel injection system provided by the utility model replaces the traditional mechanical overflow valve by arranging the electric control pressure relief valve, so that the opening of the electric control pressure relief valve can be actively adjusted, and the return oil flow rate and the inlet pressure before the oil metering unit can be flexibly controlled.

[0019] Specifically, when the engine requires a large amount of fuel, the electronically controlled pressure relief valve can be actively controlled to reduce its opening, thereby increasing the inlet pressure in front of the fuel metering unit and improving the fuel supply efficiency of the injection pump, so that the injection pump can provide more fuel to the engine and improve the power coverage of the injection pump.

[0020] In addition, when the engine is in reverse towing and no fuel injection is required, the electronically controlled pressure relief valve can be actively controlled to increase its opening to fully open, so that all the fuel after the fuel pump returns to the fuel tank, truly achieving completely zero fuel supply, and avoiding the fuel from leaking through the oil metering unit slide valve structure and entering the injection pump plunger cavity to cause rail pressure fluctuations. Therefore, the zero flow hole in the traditional system can be eliminated, simplifying the overall system structure, and avoiding the fuel from flowing back into the injection pump through the zero flow hole when the engine test bench return oil back pressure is large, causing the engine rail pressure to lose control or even the common rail pipe flush valve failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the fuel injection system provided by the utility model.

[0022] In the figure:

[0023] 1. Fuel tank;

[0024] 2. Oil pump;

[0025] 3. Electronically controlled pressure relief valve;

[0026] 4. Oil metering unit;

[0027] 5. Fuel injection pump;

[0028] 6. Common rail pipe; 61. Rail pressure sensor;

[0029] 71. Primary filter element; 711. Throttle valve; 72. Secondary filter element;

[0030] 8. Overpressure protection valve; 81. Overpressure protection tube;

[0031] 9. Bypass valve; 91. Bypass pipe;

[0032] 10. Pressure limiting valve; 110. Pressure limiting pipe;

[0033] 11. Electric pump. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0035] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0037] In the description of this embodiment, the terms "upper", "lower", "right", etc., are based on the directions or positions shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0038] This embodiment provides an engine, which includes a fuel injector and a fuel injection system.

[0039] Reference Figure 1As shown, the fuel injection system includes a fuel tank 1, a fuel delivery pump 2, an electronically controlled pressure relief valve 3, a fuel metering unit 4, a fuel injection pump 5 and a common rail pipe 6. Among them, the fuel inlet of the fuel delivery pump 2 is connected to the fuel tank 1, the fuel outlet of the fuel delivery pump 2 is connected in parallel with the fuel inlet of the fuel metering unit 4 and the fuel inlet of the electronically controlled pressure relief valve 3, the fuel outlet of the electronically controlled pressure relief valve 3 is connected to the fuel tank 1, the fuel outlet of the fuel metering unit 4 is connected to the inlet of the fuel injection pump 5, and the outlet of the fuel injection pump 5 is connected to the fuel inlet of the common rail pipe 6. The fuel inlet of the injector is connected to the fuel outlet of the common rail pipe 6.

[0040] In this embodiment, the fuel injection system replaces the traditional mechanical overflow valve by providing an electronically controlled pressure relief valve 3, so that the opening of the electronically controlled pressure relief valve 3 can be actively adjusted to flexibly control the return oil flow rate and the inlet pressure before the oil metering unit 4.

[0041] Specifically, when the engine requires a large amount of fuel, the opening of the electronically controlled pressure relief valve 3 can be actively reduced by controlling the inlet pressure in front of the fuel metering unit 4, thereby increasing the fuel supply efficiency of the injection pump 5, thereby enabling the injection pump 5 to provide more fuel to the engine and improving the power coverage of the injection pump 5.

[0042] In addition, when the engine is in reverse towing or other working conditions and no fuel injection is required, the electronically controlled pressure relief valve 3 can be actively controlled to increase its opening to be fully open, so that all the fuel after the fuel pump 2 returns to the fuel tank 1, truly achieving completely zero fuel supply, and avoiding the fuel from leaking through the slide valve structure of the oil metering unit 4 and entering the plunger cavity of the fuel injection pump 5 to cause rail pressure fluctuations. Therefore, the zero flow hole in the traditional system can be eliminated, simplifying the overall structure of the system, and avoiding the fuel from flowing back into the fuel injection pump 5 through the zero flow hole when the back pressure of the engine test bench return oil is large, causing the engine rail pressure to be out of control or even the common rail pipe 6 valve failure.

[0043] Specifically, the opening degree of the electronically controlled pressure relief valve 3 can be controlled in real time by a controller. The controller can be configured as a PCB circuit board.

[0044] In this embodiment, the fuel injection system further includes a primary filter 71, the inlet of the primary filter 71 is connected to the fuel tank 1, and the outlet of the primary filter 71 is connected to the fuel inlet of the fuel pump 2. Specifically, the fuel in the fuel tank 1 is first filtered by the primary filter 71 before entering the fuel pump 2 to remove harmful impurities brought out of the fuel tank 1.

[0045] Optionally, the primary filter element 71 is configured as a fuel filter.

[0046] In this embodiment, a throttle valve 711 is provided on the connecting pipeline between the outlet of the primary filter element 71 and the oil inlet of the oil pump 2. The throttle valve 711 can throttle and adjust the flow rate of the connecting pipeline between the outlet of the primary filter element 71 and the oil inlet of the oil pump 2.

[0047] In this embodiment, the fuel injection system further includes a secondary filter 72, the inlet of the secondary filter 72 is connected to the oil outlet of the fuel pump 2, and the outlet of the secondary filter 72 is connected in parallel to the fuel inlet of the fuel metering unit 4 and the fuel inlet of the electronically controlled pressure relief valve 3. Specifically, the fuel pumped out from the fuel pump 2 is finely filtered by the secondary filter 72 before entering the fuel metering unit 4 and the electronically controlled pressure relief valve 3, thereby removing harmful impurities in the engine oil from the oil pan and extending the service life of the components.

[0048] Optionally, the secondary filter element 72 is configured as a fuel filter.

[0049] Specifically, the primary filter element 71 and the secondary filter element 72 are both configured as diesel filters. Diesel filters can be specifically divided into diesel water separators and diesel fine filters. The important function of an oil-water separator is to separate water from diesel. The presence of water is extremely harmful to the diesel engine fuel supply system, and rust, wear, and jamming may even worsen the diesel combustion process. Due to the high sulfur content in diesel, when combustion occurs, it may even react with water to generate sulfuric acid that corrodes engine components, so the provision of a diesel filter is particularly necessary.

[0050] In this embodiment, the fuel injection system further includes an overpressure protection valve 8, an overpressure protection pipe 81 is provided between the fuel inlet and the fuel outlet of the fuel pump 2, and the overpressure protection valve 8 is provided on the overpressure protection pipe 81. The overpressure protection valve 8 is configured to guide the fuel through the overpressure protection pipe 81 from the fuel outlet to the fuel inlet of the fuel pump 2. Specifically, the opening pressure of the overpressure protection valve 8 can be set to 12 bar, and when the fuel pressure at the fuel outlet end of the fuel pump 2 is too high, the fuel can be guided back to the fuel inlet end of the fuel pump 2 to avoid damage to the fuel pump 2 and the pipeline after the pump.

[0051] In this embodiment, the fuel injection system further includes an electric pump 11, the fuel inlet of the electric pump 11 is connected to the fuel tank 1, and the fuel outlet of the electric pump 11 is connected to the inlet of the primary filter 71. Specifically, when the electric pump 11 is working, the fuel can be pumped out from the fuel tank 1 through the coarse filter, the bypass valve 9, and the secondary filter 72 to fill the subsequent oil pipe, and at the same time, the gas in the pipe is discharged through the electronically controlled pressure relief valve 3.

[0052] In this embodiment, the fuel injection system further includes a bypass valve 9, a bypass pipe 91 is provided between the fuel inlet and the fuel outlet of the fuel delivery pump 2, the bypass valve 9 is provided on the bypass pipe 91, and the bypass valve 9 is configured to unidirectionally conduct the bypass pipe 91 from the fuel inlet to the fuel outlet of the fuel delivery pump 2. Specifically, the opening pressure of the bypass valve 9 can be set to 1 bar, and when the electric pump 11 is working, an exhaust path can be provided for the low-pressure oil circuit before the fuel injection pump 5.

[0053] In this embodiment, the fuel injection system further includes a pressure limiting valve 10, a pressure limiting pipe 110 is provided between the common rail pipe 6 and the fuel tank 1, and the pressure limiting valve 10 is provided on the pressure limiting pipe 110, and the pressure limiting valve 10 is configured to unidirectionally conduct the pressure limiting pipe 110 from the common rail pipe 6 to the fuel tank 1. By providing the pressure limiting valve 10, the fuel return in the fuel injector can be prevented from flowing back, and the pressure in the high-pressure fuel rail of the common rail pipe 6 can also be released in time.

[0054] In this embodiment, the fuel injector is provided with an oil discharge port, and the fuel injector is connected to the oil tank 1 through the oil discharge port.

[0055] In this embodiment, a rail pressure sensor 61 is provided on the common rail pipe 6. The rail pressure sensor 61 is used to constantly detect the pressure in the common rail pipe 6 to ensure that the pressure in the common rail pipe 6 is maintained within a normal range.

[0056] In summary, the fuel injection system provided in this embodiment replaces the traditional mechanical overflow valve by setting the electronically controlled pressure relief valve 3. When the engine requires a large amount of fuel, the electronically controlled pressure relief valve 3 can be controlled to autonomously reduce the opening, increase the inlet pressure before the fuel metering unit 4, and thus improve the fuel injection efficiency of the fuel injection pump 5. When the engine is in a reverse dragging or other working condition, the engine does not need to inject fuel. At this time, the electronically controlled pressure relief valve 3 can be controlled to autonomously increase the opening, so that all the fuel after the fuel pump 2 returns to the fuel tank 1, thus avoiding the fuel from leaking through the sliding valve structure of the fuel metering unit 4 and entering the plunger cavity of the fuel injection pump 5 to cause rail pressure fluctuations. Since the rail pressure fluctuations are effectively avoided, the zero flow hole structure in the traditional system can be correspondingly cancelled, thereby further simplifying the overall structure of the fuel injection system, and effectively avoiding the engine rail pressure out of control caused by the fuel backflow into the fuel injection pump 5 through the zero flow hole when the engine bench has a large return oil back pressure.

[0057] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the scope of protection of the present invention. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. A fuel injection system, characterized in that: It comprises a fuel tank (1), a fuel delivery pump (2), an electronically controlled pressure relief valve (3), a fuel quantity metering unit (4), a fuel injection pump (5) and a common rail pipe (6); wherein: The oil inlet of the oil delivery pump (2) is connected to the oil tank (1), the oil outlet of the oil delivery pump (2) is connected in parallel with the oil inlet of the oil metering unit (4) and the oil inlet of the electric control pressure relief valve (3), the oil outlet of the electric control pressure relief valve (3) is connected to the oil tank (1), the oil outlet of the oil metering unit (4) is connected to the inlet of the fuel injection pump (5), and the outlet of the fuel injection pump (5) is connected to the oil inlet of the common rail pipe (6).

2. The fuel injection system according to claim 1, characterized in that: It also comprises a primary filter element (71), the inlet of the primary filter element (71) being connected to the oil tank (1), and the outlet of the primary filter element (71) being connected to the oil inlet of the oil delivery pump (2).

3. The fuel injection system according to claim 2, characterized in that: A throttle valve (711) is provided on the connecting pipeline between the outlet of the primary filter (71) and the oil inlet of the oil delivery pump (2).

4. The fuel injection system according to claim 2, characterized in that: It also comprises an electric pump (11), the oil inlet of the electric pump (11) being connected to the oil tank (1), and the oil outlet of the electric pump (11) being connected to the inlet of the primary filter element (71).

5. The fuel injection system according to claim 1, characterized in that: It also includes a secondary filter element (72), the inlet of the secondary filter element (72) is connected to the oil outlet of the oil delivery pump (2), and the outlet of the secondary filter element (72) is connected in parallel to the oil inlet of the oil metering unit (4) and the oil inlet of the electric control pressure relief valve (3).

6. The fuel injection system according to claim 1, characterized in that: It also comprises an overpressure protection valve (8); an overpressure protection pipe (81) is provided between the oil inlet and the oil outlet of the oil delivery pump (2); the overpressure protection valve (8) is arranged on the overpressure protection pipe (81); the overpressure protection valve (8) is configured to unidirectionally conduct the overpressure protection pipe (81) from the oil outlet to the oil inlet of the oil delivery pump (2).

7. The fuel injection system according to claim 1, characterized in that: It also comprises a bypass valve (9), a bypass pipe (91) is provided between the oil inlet and the oil outlet of the oil delivery pump (2), the bypass valve (9) is arranged on the bypass pipe (91), and the bypass valve (9) is configured to unidirectionally conduct the bypass pipe (91) from the oil inlet to the oil outlet of the oil delivery pump (2).

8. The fuel injection system according to claim 1, characterized in that: It also comprises a pressure limiting valve (10); a pressure limiting pipe (110) is provided between the common rail pipe (6) and the oil tank (1); the pressure limiting valve (10) is arranged on the pressure limiting pipe (110); the pressure limiting valve (10) is configured to unidirectionally conduct the pressure limiting pipe (110) in a direction from the common rail pipe (6) to the oil tank (1).

9. The fuel injection system according to claim 1, characterized in that: A rail pressure sensor (61) is provided on the common rail pipe (6).

10. An engine, characterized in that: It comprises the fuel injection system as claimed in any one of claims 1 to 9, and also comprises a fuel injector, wherein the fuel inlet of the fuel injector is connected to the fuel outlet of the common rail pipe (6).

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