Oil supply pump oil way system for high-pressure common-rail electronic control diesel engine

Abstract

The invention relates to an oil supply pump oil way system for a high-pressure common-rail electronic control diesel engine. An oil tank, a filter, a first oil delivery pump, a first valve cavity, a fuel oil metering valve, a second valve cavity, an oil inlet valve, a plunger pump and an oil outlet valve which are sequentially connected form an oil supply way; the first oil delivery pump, the first valve cavity, the overflow valve, the lubricating cavity and the oil tank form an oil return path through a first outlet; a second oil delivery pump pumps oil in the oil tank into the lubricating cavity through a gap between the two bearing bushes, and a lubricating exhaust oil way is formed under the action of a second throttling hole; after the first oil delivery pump delivers oil in the oil tank to the second valve cavity, an exhaust oil way is formed through the first throttling hole; oil in the first valve cavity enters the lubricating cavity through a first outlet of the overflow valve and flows to an inlet of the first oil delivery pump through a gap between the two bearing bushes, and a lubricating oil way is formed under the action of the second throttling hole. The first oil delivery pump, the first valve cavity and the overflow valve form a safety oil way through the first outlet, and the first valve cavity, the overflow valve, the lubricating cavity and the first oil delivery pump form another safety oil way through the second outlet.

Description

Technical Field

[0001] The present invention relates to the technical field of high-pressure common-rail electronically controlled diesel engines, and particularly to a fuel supply pump oil circuit system for a high-pressure common-rail electronically controlled diesel engine. Background Art

[0002] The high-pressure fuel supply pump is an important part of the high-pressure common-rail system, and it is a device that provides high-pressure fuel for a diesel engine.

[0003] In a diesel engine, when the high-pressure fuel supply pump has a blocked return oil, fuel continuously enters the lubrication cavity of the plunger pump. While the pressure inside the lubrication cavity is continuously increasing, the pressure inside the oil seal is also increasing, resulting in the loosening or detachment of the oil seal, causing the oil seal to fail. At the same time, the high-pressure oil pump also stops working, reducing reliability.

[0004] In addition, during the normal operation of the existing high-pressure fuel supply pump, it cannot exhaust air. It can only be initially exhausted during the pre-fuel supply stage when installing or replacing its internal structural components, which directly affects diesel injection and engine performance. Therefore, in the fuel supply system of a diesel engine, the exhaust of the fuel supply pump is an important issue. Summary of the Invention

[0005] Based on this, the present invention provides a fuel supply pump oil circuit system for a high-pressure common-rail electronically controlled diesel engine. This system realizes the functions of avoiding oil seal failure when the high-pressure fuel supply pump has a blocked return oil and exhausting air during normal operation.

[0006] To achieve the foregoing objectives, the present invention adopts the following technical solutions:

[0007] A fuel supply pump oil circuit system for a high-pressure common-rail electronically controlled diesel engine, comprising a fuel tank, a filter, a first fuel pump, a first valve chamber, a fuel metering valve, a second valve chamber, an inlet valve, a plunger pump, and an outlet valve. The second valve chamber is connected to the fuel tank, and a first throttle hole is provided on the pipeline. The plunger pump includes a plunger, a plunger sleeve, a cam mechanism, and a drive shaft. The drive shaft drives the cam mechanism to drive the plunger to move within the plunger sleeve. The connection between the cam mechanism and the plunger is disposed in a lubrication cavity. A first bearing bush and a second bearing bush are provided in the lubrication cavity. A first bearing bush gap and a second bearing bush gap are respectively formed between the first bearing bush and the second bearing bush and the drive shaft. The first bearing bush gap and the second bearing bush gap are both connected to the inlet of the first fuel pump and the lubrication cavity. The lubrication cavity is communicated with the fuel tank, and a second throttle hole is provided on the pipeline. A second fuel pump is connected in parallel between the filter and the fuel tank. The first valve chamber is connected to the inlet of a relief valve. The relief valve is provided with a first outlet connecting to the lubrication cavity and a second outlet connecting to the inlet of the first fuel pump. Wherein:

[0008] The fuel tank, filter, first fuel pump, first valve chamber, fuel metering valve, second valve chamber, inlet valve, plunger pump and outlet valve are connected in sequence to form an oil supply circuit;

[0009] The first fuel pump, first valve chamber, overflow valve, lubrication chamber and fuel tank form a return oil circuit through the first outlet;

[0010] The second fuel pump pumps the oil in the fuel tank into the lubrication chamber through the first bearing clearance and the second bearing clearance, and forms a lubricating and exhaust oil circuit under the action of the second throttle hole;

[0011] The first fuel pump sequentially transports the oil in the fuel tank to the first valve chamber, fuel metering valve and second valve chamber, and the air therein is discharged through the first throttle hole, forming an exhaust oil circuit;

[0012] The oil in the first valve chamber enters the lubrication chamber through the first outlet of the overflow valve, and flows to the inlet of the first fuel pump through the first bearing clearance and the second bearing clearance, forming a lubricating oil circuit;

[0013] The first fuel pump, first valve chamber and overflow valve are connected end to end, and form a safety oil circuit through the first outlet. The first valve chamber, overflow valve, lubrication chamber and first fuel pump are connected end to end, and form another safety oil circuit through the second outlet.

[0014] Further, the oil supply circuit further includes a common rail pipe, and the outlet of the outlet valve is connected to the inlet of the common rail pipe.

[0015] Further, the oil supply circuit further includes an injector;

[0016] The outlet of the common rail pipe is connected to the inlet of the injector.

[0017] Further, the cam mechanism includes a roller and a cam. The roller is sleeved on the cam and its edge contacts the plunger. The drive shaft is in transmission connection with the cam. The drive shaft drives the cam to drive the roller to move, and further drives the plunger to move. The lubrication chamber is used to lubricate the friction between the roller and the cam and between the roller and the plunger;

[0018] The cam mechanism is in transmission connection with the drive shaft, and the plunger is arranged in contact with the outer edge of the cam mechanism.

[0019] Further, the plunger pump further includes an oil outlet passage, and the oil outlet passage communicates the common rail pipe and the outlet valve; the included angle α between the extension line of the oil outlet passage and the movement direction of the plunger in the plunger pump ranges from 0° to 18°.

[0020] Further, when the pressure value in the first valve chamber is greater than the first preset pressure value, the first outlet of the overflow valve opens; when the pressure value in the first valve chamber is greater than the second preset pressure value, the first outlet and the second outlet of the overflow valve open simultaneously;

[0021] The first preset pressure value is less than the second preset pressure value.

[0022] Further, a first bearing oil return oil passage and a second bearing oil return oil passage are provided between the lubrication chamber and the first oil pump, and are respectively connected to the first bearing clearance and the second bearing clearance.

[0023] Further, the number of the plunger pumps in the oil supply circuit is one or more.

[0024] Further, the first oil pump is a sliding vane pump, an external gear pump, an internal gear pump, a trochoidal gear pump or an electric pump.

[0025] Further, a key connection is provided between the first oil pump and the drive shaft;

[0026] The key is a flat key, a half-round key or a spline key.

[0027] During actual use, the fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine provided by the present invention can be used for diesel engines used in equipment such as heavy trucks for heavy-duty transportation, passenger cars for long-distance transportation, ships, generator sets, and construction machinery.

[0028] The fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine provided by the present invention has the following beneficial effects:

[0029] In the technical solution adopted by the present invention, when the pressure in the oil return circuit is too high, the excess fuel flows back to the fuel tank, avoiding problems such as overpressure and leakage in the system. Through the lubricating exhaust oil circuit and the exhaust oil circuit, before the fuel supply pump works normally, the fuel is pumped out of the fuel tank by the second fuel pump, reaches the inlet of the first fuel pump after passing through the filter, and then enters the inside of the lubricating cavity through the first bearing clearance and the second bearing clearance. While the lubricating cavity is gradually filled with fuel, the air inside it is discharged to the fuel tank through the second throttle hole; when the fuel supply pump works normally, the fuel is transported to the first valve cavity by the first fuel pump and enters the second valve cavity through the fuel metering valve. At this time, the air inside it is discharged to the fuel tank through the first throttle hole, realizing that the fuel supply pump can exhaust gas during the pre-fuel supply stage after the initial installation or replacement of its internal structural components, as well as during the normal operation of the fuel supply pump, effectively improving the convenience of use. Through the lubricating exhaust oil circuit and the lubricating oil circuit, before the fuel supply pump works normally, the fuel is pumped out of the fuel tank by the second fuel pump, reaches the inlet of the first fuel pump after passing through the filter, and then enters the inside of the lubricating cavity through the first bearing clearance and the second bearing clearance. When the fuel supply pump works normally, the fuel directly enters the inside of the lubricating cavity through the first outlet to lubricate the plunger, cam mechanism, drive shaft and bearing, thus realizing that the internal structural components of the plunger pump can be lubricated during both the pre-fuel supply stage and the normal operation stage of the fuel supply pump. The lubrication process is continuous, effectively improving the stability of lubrication. Through the safety oil circuit, when the pressure in the first valve cavity rises to a certain level, the first outlet of the overflow valve opens, and the fuel enters the lubricating cavity through the first outlet of the overflow valve. When the pressure in the first valve cavity continues to rise and causes the second outlet of the overflow valve to open, the fuel returns to the inlet of the fuel pump again through the second outlet of the overflow valve and continues the fuel supply cycle, avoiding the situation where the pressure inside the lubricating cavity increases and the oil seal fails when the oil return circuit of the high-pressure fuel supply pump is blocked, improving the reliability.

[0030] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and do not limit the present application. Brief Description of the Drawings

[0031] The drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0032] Figure 1 is the schematic diagram of the fuel supply pump oil circuit system according to the embodiment of the present invention;

[0033] Figure 2 is Figure 1 the fuel flow diagram when the fuel supply pump oil circuit system shown is initially supplied with fuel;

[0034] Figure 3 is Figure 1Fuel flow diagram when the fuel supply pump oil circuit system shown is working properly;

[0035] Figure 4 Schematic structural diagram of the fuel supply pump oil circuit system according to an embodiment of the present invention.

[0036] 100 - fuel tank; 101 - first fuel pump; 102 - filter; 103 - second fuel pump; 104 - fuel metering valve; 105 - inlet valve; 106 - overflow valve; 107 - plunger pump; 108 - plunger; 109 - lubrication chamber; 110 - drive shaft; 111 - cam mechanism; 112 - outlet valve; 113 - common rail; 114 - injector; 115 - first valve chamber; 116 - second valve chamber; 117 - oil outlet passage; 118 - key; 200 - first throttle hole; 201 - second throttle hole; 300 - first outlet; 301 - second outlet; 400 - first bearing clearance; 401 - second bearing clearance; 402 - first bearing oil return passage. Detailed implementation mode

[0037] Here, exemplary embodiments will be described in detail, and examples thereof are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation modes described in the following exemplary embodiments do not represent all implementation modes consistent with the present application.

[0038] The terms used in the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "the" and "said" used in the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0039] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0040] A fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine provided by the present invention includes a fuel tank 100, a filter 102, a first fuel pump 101, a first valve chamber 115, a fuel metering valve 104, a second valve chamber 116, an inlet valve 105, a plunger pump 107 and an outlet valve 112. The second valve chamber 116 is connected to the fuel tank 100, and a first throttle hole 200 is provided on the pipeline. The plunger pump 107 includes a plunger 108, a plunger sleeve, a cam mechanism 111 and a drive shaft 110. The drive shaft 110 drives the cam mechanism 111 to drive the plunger 108 to move in the plunger sleeve. A connection part between the cam mechanism 111 and the plunger 108 is arranged in a lubrication chamber 109. A first bearing bush and a second bearing bush are arranged in the lubrication chamber 109. A first bearing bush gap 400 and a second bearing bush gap 401 are respectively formed between the first bearing bush and the second bearing bush and the drive shaft 110. The first bearing bush gap 400 and the second bearing bush gap 401 are both connected to the inlet of the first fuel pump 101 and the lubrication chamber 109. The lubrication chamber 109 is communicated with the fuel tank 100, and a second throttle hole 201 is provided on the pipeline. A second fuel pump 103 is connected in parallel between the filter 102 and the fuel tank 100. The first valve chamber 115 is connected to the inlet of an overflow valve 106. The overflow valve 106 is provided with a first outlet 300 connected to the lubrication chamber 109 and a second outlet 302 connected to the inlet of the first fuel pump 101. Wherein:

[0041] The fuel tank 100, the filter 102, the first fuel pump 101, the first valve chamber 115, the fuel metering valve 104, the second valve chamber 116, the inlet valve 105, the plunger pump 107 and the outlet valve 112 are connected in sequence to form a fuel supply oil circuit;

[0042] The first fuel pump 101, the first valve chamber 115, the overflow valve 106, the lubrication chamber 109 and the fuel tank 100 form a return oil circuit through the first outlet 300;

[0043] The second fuel pump 103 pumps the oil in the fuel tank 100 into the lubrication chamber 109 through the first bearing bush gap 400 and the second bearing bush gap 401, and forms a lubrication and exhaust oil circuit under the action of the second throttle hole 201;

[0044] The first fuel pump 101 sequentially transports the oil in the fuel tank 100 to the first valve chamber 115, the fuel metering valve 104 and the second valve chamber 116, and the air therein is discharged through the first throttle hole 200 to form an exhaust oil circuit;

[0045] The oil in the first valve chamber 115 enters the lubrication chamber 109 through the first outlet 300 of the overflow valve 106, and flows to the inlet of the first fuel pump 101 through the first bearing bush gap 400 and the second bearing bush gap 401 to form a lubricating oil circuit;

[0046] The first fuel pump 101, the first valve chamber 115, and the overflow valve 106 are connected end to end to form a safety oil circuit through the first outlet 300. The first valve chamber 115, the overflow valve 106, the lubrication chamber 109, and the first fuel pump 101 are connected end to end to form another safety oil circuit through the second outlet 301.

[0047] The following is combined with Figures 1-4 to further describe the system.

[0048] The fuel supply oil circuit includes a fuel tank 100, a filter 102, a first fuel pump 101, a second fuel pump 103, a first valve chamber 115, a fuel metering valve 104, a second valve chamber 116, an inlet valve 105, a plunger pump 107, and an outlet valve 112. The fuel tank 100 is connected to the inlet of the first fuel pump 101 through the filter 102. The second fuel pump 103 is bypassed between the filter 102 and the fuel tank 100. The filter 102 is used to filter impurities and gases in the diesel to make the diesel cleaner to meet specific requirements, thereby reducing the wear of precision structural parts such as the first fuel pump 101 and the injector 114 caused by gas. Commonly used filters 102 currently include, but are not limited to, single-stage diesel filters and double-stage diesel filters. The cover of the single-stage diesel filter is provided with a bleeder screw and a pressure limiting valve. When the diesel passes through the filter 102, the water precipitates in the shell, and impurities are filtered by the filter element. The bleeder screw is used to discharge the air in the low-pressure oil circuit. When the pressure in the filter 102 exceeds the opening pressure of the pressure limiting valve, the pressure limiting valve opens and returns the excess fuel to the fuel tank; during the actual use of the diesel filter, regular maintenance or replacement is required to enhance the service life of the diesel filter.

[0049] There is a key connection between the first fuel pump and the drive shaft. For example, the key can be a flat key, a semi-circular key or a spline key. The first fuel pump 101 is driven under the mutual cooperation of the drive shaft 110 and the key 118. By changing the pressure through the change of the internal volume of the first fuel pump 101, the fuel is pumped out from the fuel tank 100. The outlet of the first fuel pump 101 is connected to a first valve chamber 115. The first valve chamber 115 is also connected to a fuel metering valve 104. The first valve chamber 115 is connected to the inlet of the fuel metering valve 104. The outlet of the fuel metering valve 104 is connected to a second valve chamber 116. The second valve chamber 116 is also connected to an inlet valve 105. The second valve chamber 116 is connected to the inlet of the inlet valve 105. The outlet of the inlet valve 105 is connected to a plunger pump 107. The outlet of the inlet valve 105 is connected to the inlet of the plunger pump 107. The outlet of the plunger pump 107 is connected to an outlet valve 112. The outlet of the plunger pump 107 is connected to the inlet of the outlet valve 112. The outlet of the outlet valve 112 is connected to a common rail 113. The outlet of the outlet valve 112 is connected to the inlet of the common rail 113. The outlet of the common rail 113 is connected to an injector 114. The outlet of the common rail 113 is connected to the inlet of the injector 114. The outlet of the injector 114 is connected to the engine combustion chamber. That is to say, after the fuel is filtered by the filter 102 to remove impurities and air in the oil, it enters the first fuel pump 101, and then is sent to the first valve chamber 115 by the first fuel pump 101. The fuel enters the fuel metering valve 104. The fuel metering valve 104 is regulated by the ECU to adjust the fuel quantity and opening rhythm. The regulated fuel enters the second valve chamber 116 and reaches the inlet of the inlet valve 105. The plunger 108 of the plunger pump 107 moves downward following the cam mechanism 111 on the drive shaft 110. The internal volume of the plunger pump 107 becomes larger, and the pressure in the lubricating chamber 109 decreases. The oil pressure difference between the inlet and outlet of the inlet valve 105 is greater than the opening pressure of the inlet valve 105, and the fuel is sucked into the plunger pump 107, thus completing the oil suction process. When the plunger 108 moves upward with the cam mechanism 111 of the drive shaft 110, the plunger 108 compresses the fuel to increase the fuel pressure. At this time, the pressure behind the inlet valve 105 is greater than the pressure in front of the inlet valve 105, and the inlet valve 105 closes. At the same time, the pressure in the plunger pump 107 is greater than the opening pressure of the outlet valve 105, and the outlet valve 112 opens. The fuel enters the common rail 113 through the outlet valve 112. The pressure accumulates in the common rail 113 and then enters the injector 114 from the common rail 113. After being regulated by the ECU to inject, the fuel enters the engine for combustion, thus completing the fuel supply process. For example, the outer edge of the cam mechanism and the flat-bottom plunger, where the outer edge of the cam mechanism is in direct contact with the bottom of the flat-bottom plunger; the cam mechanism is sleeved in a circular roller, where the outer edge of the roller is in contact with the flat bottom of the plunger; the cam mechanism is sleeved in a roller with a square outside and a round inside, where the outer square plane of the roller is in contact with the flat bottom of the plunger; the bottom of the plunger is directly or indirectly connected to the roller, where the outer edge of the roller is in contact with the outer edge of the cam mechanism.

[0050] In this embodiment, the first fuel pump is a sliding vane pump, an external gear pump, an internal gear pump, a trochoidal gear pump or an electric pump. Preferably, the first fuel pump 101 is an automatic oil pump, and in the direction of fuel flow, the first valve chamber is the pre-valve chamber and the second valve chamber is the post-valve chamber. The connection mode of the first fuel pump 101 to the pipeline includes but is not limited to threaded connection, hinged connection, plug connection, etc. Among them, the first fuel pump 101 includes but is not limited to a pump body, and the pump body is provided with an inlet and an outlet. Specifically, the first fuel pump 101 realizes the change of pressure by changing the internal volume. The fuel in the fuel tank 100 is filtered by the filter 102 to remove impurities or fine particles, then enters the first fuel pump 101, and is transported to the first valve chamber 115 through the first fuel pump 101. The fuel enters the fuel metering valve 104. Further, the fuel metering valve 104 is connected to an electronic control unit, and the electronic control unit regulates the fuel passing amount and the opening frequency of the fuel metering valve 104; the fuel passing through the fuel metering valve 104 enters the interior of the second valve chamber 116 until the fuel reaches the inlet of the inlet valve 105.

[0051] The fuel metering valve 104 includes but is not limited to a valve body, a valve seat, a valve core, an end cover, an electromagnetic assembly, and a moving assembly. The fuel metering valve 104 is used to control the fuel flow rate, and can control its passing amount through the electronic control unit according to the actual use requirements and the working conditions of the engine. In this embodiment, by controlling the fuel passing amount through the fuel metering valve 104, the fuel amount input to the inlet valve 105 and the fuel amount returning to the fuel tank 100 through the first throttle hole 200 are controlled, realizing the precise control of the fuel usage amount during the normal operation of the fuel supply pump, effectively improving the fuel utilization rate, and enhancing the performance of the diesel engine.

[0052] The inlet valve 105 is a one-way valve. Under the action of the spring, the conical surface on the upper part of the valve fits tightly with the valve seat. It only allows fuel to flow freely in one direction and prevents fuel from flowing in the opposite direction. The pressure difference between the inlet and outlet of the inlet valve 105 is greater than the opening pressure of the inlet valve 105, and the inlet valve 105 opens, and the fuel is input into the inner cavity of the plunger pump 107 through the inlet valve 105.

[0053] The plunger pump 107 includes but is not limited to a single plunger pump, a horizontal plunger pump, an axial plunger pump and a radial plunger pump; the single plunger pump includes a cam, a plunger, a spring, a cylinder block and two one-way valves. A sealed volume is formed between the plunger and the cylinder block hole. The lobe number of the cam refers to the number of raised parts on the cam. In the cam, each raised part corresponds to the movement of a plunger. Therefore, the lobe number of the cam determines the movement times of the plunger, that is, the lobe number of the cam corresponds to the number of times the plunger reciprocates up and down. The plunger moves downward to suck oil and moves upward to discharge oil.

[0054] For example, in the plunger pump 107, the cam mechanism 111 may include a roller and a cam. The roller is sleeved on the cam and its edge contacts the plunger 108. The drive shaft 110 is in transmission connection with the cam. The drive shaft 110 drives the cam, drives the roller to move, and further drives the plunger 108 to move. The lubrication cavity 109 is used to lubricate the friction between the roller and the cam and between the roller and the plunger 108.

[0055] In this embodiment, the number of plunger pumps 107 is one or more. The internal pressure of the plunger pump 107 is inversely proportional to the internal cavity volume of the plunger sleeve, so as to realize the reduction of the plunger sleeve volume and fuel output, and the increase of the plunger sleeve volume and fuel input. The internal pressure of the plunger pump 107 decreases as the internal cavity volume of the plunger sleeve increases. When the plunger 108 compresses the fuel, the fuel pressure increases. The plunger 108 in the plunger sleeve moves along with the cam mechanism 111 on the drive shaft 110. When the cam mechanism 111 moves upward, the plunger 108 moves upward, the internal cavity volume of the plunger sleeve decreases, and its internal pressure increases. When the cam mechanism 111 moves downward, the plunger 108 moves downward, the internal cavity volume of the plunger sleeve increases, and the internal pressure of the plunger pump 107 decreases.

[0056] The fuel outlet valve 112 is also a one-way valve, and the fuel outlet valve plays a key role in controlling the fuel pressure in the common rail pipe during the normal operation of the high-pressure fuel supply pump. Continue to refer to Figure 4 , in this embodiment, when the plunger 108 moves upward, the inlet valve 105 is closed. At this time, the fuel is input into the common rail pipe 113 through the fuel outlet valve 112. The common rail pipe 113 includes but is not limited to a common rail pipe body, a plug, a sealing ring, a pressure sensor, etc. The pressure sensor is connected to the electronic control unit to realize the negative feedback adjustment of the signal. The common rail pipe body is respectively provided with a fuel inlet and a fuel outlet.

[0057] The common rail pipe 113 is usually filled with high-pressure fuel, so as to realize the input of a preset dose of fuel into the common rail pipe 113 through the fuel outlet valve 112, make full use of the compression of the high pressure on the fuel to maintain the storage pressure, and use a high-pressure pump to compensate for the pressure fluctuation generated by the pulsating fuel supply. Therefore, the pressure in the common rail pipe 113 is approximately constant, thus playing the role of a constant rail pressure. The common rail pipe 113 also has the functions of buffering pulses and storing high-pressure oil. In this embodiment, the fuel input into the common rail pipe 113 by the fuel outlet valve 112 accumulates pressure in the common rail pipe 113 and then is input into the injector 114 from the common rail pipe 113, effectively improving the utilization rate of fuel combustion.

[0058] The outlet connection surface area of the common rail pipe 113 should be large enough to realize the fluidity of the fuel entering the injector 114 and the injection effect of the injector. At the same time, an appropriate inlet area of the injector 114 is also required to ensure efficient fuel injection and uniform combustion.

[0059] The fuel injector 114 is a precision device with very high machining accuracy, requiring a large dynamic flow range, having an effective fuel injection start point and accurate fuel injection quantity, being strong in anti-blocking and anti-pollution capabilities, having good atomization performance. At the same time, the spray characteristics of the fuel injector 114, including atomization particle size, oil mist distribution, oil spray direction, range, and diffusion cone angle, etc., should all meet the requirements of the diesel engine combustion system, so as to make the fuel combustion perfect, obtain higher power and thermal efficiency. The fuel injector 114 includes but is not limited to a nozzle, a control mechanism, an oil circuit, etc. The electronic control unit (ECU) is mainly used to control various functions of the vehicle, constantly monitoring various input data, such as, by way of example, braking, shifting gears, accelerating, skidding, fuel consumption, etc., and calculating the signals sent by various sensors according to a pre-designed program. After being processed, the signals are sent to the relevant actuators to perform various predetermined control functions, such as, by way of example, engine start / stop, transmission speed increase / decrease, and other system functions. In this embodiment, under the regulation and control of the electronic control unit, the fuel injector 114 injects fuel into the engine combustion chamber for combustion to complete fuel supply.

[0060] In this embodiment, the second fuel pump 103 is a manual fuel pump. The manual fuel pump is mainly an airbag-type manual fuel pump and a plunger-type manual fuel pump. The main component of the airbag-type manual fuel pump is a rubber airbag, which exhausts and inhales air through the repeated actions of manual pressing and rubber elasticity; the plunger-type manual fuel pump exhausts and inhales air by manually pulling and pushing, and the plunger reciprocates inside the pump body to discharge the air in the oil circuit.

[0061] The first fuel pump 101, the first valve chamber 115, the overflow valve 106, the lubrication chamber 109, and the fuel tank 100 form a return oil circuit through the first outlet 300; the inlet of the overflow valve 106 is used to connect with the first valve chamber 115. The overflow valve 106 is respectively provided with a first outlet 300, and the first outlet 300 is connected to the lubrication chamber 109; the overflow valve 106 is a hydraulic pressure control valve, having the functions of constant pressure overflow, voltage stabilization, system unloading, and safety protection. When the pressure in the system exceeds the set value, the valve of the overflow valve 106 will automatically open, and the excess fuel will flow back to the fuel tank 100, thus avoiding problems such as system overpressure and leakage. Further, the overflow valve 106 can also adjust parameters such as spring force and spool position to realize the adjustment of the opening pressure of the overflow valve 106 within a certain range according to actual needs.

[0062] The maximum flow rate and the minimum stable flow rate of the overflow valve determine the flow rate adjustment range of the overflow valve. The wider the flow rate adjustment range of the overflow valve, the wider its application range. The maximum flow rate of the overflow valve is the nominal flow rate of the overflow valve, also known as the rated flow rate. At this flow rate, the overflow valve operates without noise. The minimum stable flow rate of the overflow valve depends on its pressure stability requirement. In this embodiment, the inlet of the overflow valve 106 is connected to the first valve chamber 115. The overflow valve 106 is respectively provided with a first outlet 300 and a second outlet 301. The first outlet 300 is connected to the lubrication chamber 109, and the second outlet 301 is connected to the inlet of the first fuel pump 101. The opening pressure of the second outlet 301 is greater than the opening pressure of the first outlet 300. In other embodiments, by reasonably setting the opening pressure of the first outlet 300, it is ensured that at low rotational speeds, limited fuel is not used for lubrication, improving the overall fuel supply efficiency of the fuel pump.

[0063] The second fuel pump 103 pumps the oil in the fuel tank 100 into the lubrication chamber 109 through the first bearing clearance 400 and the second bearing clearance 401, forming a lubrication and exhaust oil circuit under the action of the second throttle hole 201; the first fuel pump 101 sequentially transports the oil in the fuel tank 100 to the first valve chamber 115, the fuel metering valve 104, and the second valve chamber 116, and the air therein is discharged through the first throttle hole 200, forming an exhaust oil circuit; the oil in the first valve chamber 115 enters the lubrication chamber 109 through the first outlet 300 of the overflow valve 106 and flows to the inlet of the first fuel pump 101 through the first bearing clearance 400 and the second bearing clearance 401, forming a lubricating oil circuit. The first throttle hole 200 is arranged on the pipeline between the second valve chamber 116 and the fuel tank 100 and is used to control the fuel flow rate in the pipeline between the second valve chamber 116 and the fuel tank 100; the second throttle hole 201 is arranged on the pipeline between the lubrication chamber 109 and the fuel tank 100 to increase the pressure in the lubrication chamber 109 to achieve pressure lubrication and is used to control the fuel flow rate in the pipeline between the lubrication chamber 109 and the fuel tank 100. Both the first throttle hole 200 and the second throttle hole 201 are small holes that can control the flow rate and are usually used to adjust the flow velocity of liquids or gases in pipelines. By adjusting factors such as the aperture, length, shape, and position, different flow rate control effects can be achieved. The inlet of the first throttle hole 200 is connected to the second valve chamber 116, and the outlet of the first throttle hole 200 is connected to the fuel tank 100; the inlet of the second throttle hole 201 is connected to the lubrication chamber 109, and the outlet of the second throttle hole 201 is also connected to the fuel tank 100.

[0064] In the lubricating and exhaust oil circuit, before the fuel supply pump works normally, fuel is pumped out of the fuel tank 100 by the second fuel pump 103, reaches the inlet of the first fuel pump 101 after passing through the filter 102, and then enters the interior of the lubricating chamber 109 through the first bearing clearance 400 and the second bearing clearance 401. While the fuel gradually fills the lubricating chamber 109 to achieve the lubricating function, the air inside it is discharged to the fuel tank 100 through the second throttle hole 201. When the fuel supply pump works normally in the exhaust oil circuit, the fuel is transported to the first valve chamber 115 by the first fuel pump 101 and input into the second valve chamber 116 through the fuel metering valve 104. At this time, the air inside it is discharged to the fuel tank 100 through the first throttle hole 200. In this embodiment, when the fuel supply pump enters the pre-fuel supply stage after being initially installed or having its internal structural parts replaced, the air is discharged to the fuel tank 100 successively through the lubricating chamber 109 and the second throttle hole 201. When the fuel supply pump is working normally, the air is discharged to the fuel tank 100 successively through the first throttle hole 200. The above two oil circuits enable the fuel supply pump to exhaust not only during the pre-fuel supply stage but also during the normal working process, effectively improving the convenience of use, avoiding the situation of insufficient fuel supply pressure due to the presence of air in its oil circuit during use, and further enhancing the stability of the fuel supply pump during use.

[0065] In this embodiment, after the fuel is input into the first fuel pump 101 and transported to the first valve chamber 115 by the first fuel pump 101, a part of the fuel is input into the second valve chamber 116 through the fuel metering valve 104, then enters the external oil return circuit through the first throttle hole 200 and returns to the fuel tank 100, while the remaining fuel accumulates inside the first valve chamber 115. At the same time, the pressure inside the first valve chamber 115 gradually increases. When the pressure in the first valve chamber 115 increases to a certain extent, the first outlet 300 opens, and the fuel enters the interior of the lubricating chamber 109 through the first outlet 300 and returns to the fuel tank 100 through the second throttle hole 201, so as to ensure sufficient fuel supply while being able to lubricate the plunger 108, the cam mechanism 111, the drive shaft 110 and the bearing, and being able to collect the fuel again, providing sufficient fuel quantity for the fuel to be input into the first fuel pump 101 and effectively improving the fuel supply efficiency.

[0066] In the lubricating oil circuit, the first bearing shell and the second bearing shell respectively form a first bearing shell gap and a second bearing shell gap with the driving shaft, and the first bearing shell gap and the second bearing shell gap are both connected to the inlet of the first oil pump, and the first bearing shell gap and the second bearing shell gap are also connected to the lubrication cavity; usually there is relative motion between the bearing shell and the shaft, and the first bearing shell and the second bearing shell have the functions of reducing friction, reducing wear and increasing the service life of the shaft. Specifically, when the shaft rotates in the bearing shell, a certain amount of heat will be generated due to the friction. If the contact surface between the shaft and the bearing shell is not good, and only a few points or a few surfaces are in contact, the oil film between the bearing shell and the shaft will be destroyed. At the position where the oil film is destroyed, the pressure and friction generated between the shaft and the bearing shell are large. During operation, a large amount of heat will be generated, which increases the temperature of the bearing. On the contrary, when the contact between the shaft and the bearing shell is complete, the force between the shaft and the bearing shell is uniform, the oil film between the contact surfaces is complete, and the heat generated by the interaction between the shaft and the bearing shell is small and easy to dissipate, so that the bearing will not generate a high temperature.

[0067] In this embodiment, the first bearing gap 400 and the second bearing gap 401 are both connected to the inlet of the first oil pump 101, and the first bearing gap 400 and the second bearing gap 401 are also connected to the lubrication chamber 109, and a first bearing return oil channel 402 is arranged between the lubrication chamber 109 and the first oil pump 101. Before the oil supply pump works normally, the fuel is pumped out from the fuel tank 100 by the second oil pump 103, reaches the inlet of the first oil pump 101 through the filter 102, and then enters the lubrication chamber 109 through the first bearing gap 400 and the second bearing gap 401. When the oil supply pump works normally, the fuel directly enters the lubrication chamber 109 through the first outlet 300. At this time, the second throttle hole 201 limits the return oil flow rate and increases the pressure in the lubrication chamber 109 to pressure lubricate the plunger 108, cam mechanism 111, drive shaft 110 and bearing, thereby achieving lubrication of the internal structural parts of the plunger pump 107 during both the pre-oil supply stage and the normal working stage of the oil supply pump, and the lubrication process is continuous, which effectively improves the stability of the lubrication.

[0068] The first oil pump 101, the first valve chamber 115, and the relief valve 106 are connected head to tail, and a safety oil circuit is formed through the first outlet 300. The first valve chamber 115, the relief valve 106, the lubrication chamber 109, and the first oil pump 101 are connected head to tail, and another safety oil circuit is formed through the second outlet 301. The relief valve 106 is also provided with a second outlet 301, and the second outlet 301 is used to connect with the inlet of the first oil pump 101. When the pressure value of the first valve chamber 115 is greater than the first preset pressure value, the first outlet 300 of the relief valve 106 is opened; when the pressure value of the first valve chamber 115 is greater than the second preset pressure value, the first outlet 300 and the second outlet 301 of the relief valve 106 are opened at the same time. For example, the first preset pressure value is less than the second preset pressure value, so that the first outlet 300 and the second outlet 301 are opened in stages according to the internal pressure level of the relief valve 106; the specific first preset pressure value and the second preset pressure value can be selected according to actual conditions.

[0069] After the pressure in the first valve chamber 115 rises to a certain level, the first outlet 300 opens, and the fuel enters the lubrication chamber 109 through the first outlet 300. When the pressure in the first valve chamber 115 continues to increase, causing the second outlet 301 to open, the fuel returns to the inlet of the first oil pump 101 through the second outlet 301 and continues the oil supply cycle, thereby avoiding the situation in which the pressure inside the lubrication chamber 109 increases and the oil seal fails when the return oil path of the first oil pump 101 is blocked. The pressure in the first valve chamber 115 is effectively maintained stable, the reliability is improved, and the oil supply of the first oil pump 101 is sufficient, thereby ensuring the lubrication function inside the plunger pump 107 in the oil supply pump and the sufficient oil supply of the first oil pump 101 in the oil supply pump, thereby effectively improving the oil supply efficiency.

[0070] For example, Figure 4 As shown, the plunger pump 107 also includes an oil outlet 117, which connects the common rail pipe 113 and the oil outlet valve 12; in order to complete the oil channel layout in a limited space and avoid causing fluid flow obstruction, the angle α formed by the extension line of the oil outlet and the movement direction of the plunger in the plunger pump ranges from 0° to 18°, for example, α can be 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17° or 18°; the specific value of α can be selected according to actual design needs. Here, the angle α formed by the extension line of the oil outlet 117 and the movement direction of the plunger in the plunger pump is designed to be an acute angle, which is conducive to the extraction of fuel from the oil outlet valve 112.

[0071] Other embodiments of the present application will be readily contemplated by those skilled in the art upon consideration of the specification and practice of the disclosure herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include known common general knowledge or conventional technical means in the technical field not disclosed in the present application.

[0072] It should be understood that the present application is not limited to the exact construction described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine, characterized in that: The invention comprises a fuel tank, a filter, a first fuel pump, a first valve chamber, a fuel metering valve, a second valve chamber, a fuel inlet valve, a plunger pump and a fuel outlet valve, wherein the second valve chamber is connected to the fuel tank and a first throttling hole is arranged on the pipeline, the plunger pump comprises a plunger, a plunger sleeve, a cam mechanism and a driving shaft, the driving shaft drives the cam mechanism to drive the plunger to move in the plunger sleeve, the connection between the cam mechanism and the plunger is arranged in a lubrication chamber, a first bearing bush and a second bearing bush are arranged in the lubrication chamber, a first bearing bush gap and a second bearing bush gap are formed between the first bearing bush and the second bearing bush and the driving shaft respectively, the first bearing bush gap and the second bearing bush gap are both connected to the inlet of the first fuel pump and the lubrication chamber, the lubrication chamber is connected to the fuel tank and a second throttling hole is arranged on the pipeline; a second fuel pump is connected between the filter and the fuel tank; the first valve chamber is connected to the inlet of an overflow valve, the overflow valve is provided with a first outlet connected to the lubrication chamber and a second outlet connected to the inlet of the first fuel pump; wherein: The oil tank, the filter, the first oil delivery pump, the first valve chamber, the fuel metering valve, the second valve chamber, the oil inlet valve, the plunger pump and the oil outlet valve are connected in sequence to form an oil supply circuit; The first oil delivery pump, the first valve chamber, the relief valve, the lubrication chamber and the oil tank form an oil return circuit through the first outlet; The second oil delivery pump pumps the oil in the oil tank into the lubrication cavity through the first bearing clearance and the second bearing clearance, and forms a lubrication and exhaust oil path under the action of the second throttle hole; The first oil delivery pump delivers the oil in the oil tank to the first valve chamber, the fuel metering valve, and the second valve chamber in sequence, and the air therein is discharged through the first throttle hole to form an exhaust oil circuit; The oil in the first valve chamber enters the lubrication chamber through the first outlet of the relief valve, flows to the inlet of the first oil pump through the first bearing bush gap and the second bearing bush gap, and forms a lubrication oil path under the action of the second throttle port; The first oil pump, the first valve chamber, and the relief valve are connected head to tail, forming a safety oil circuit through the first outlet; the first valve chamber, the relief valve, the lubrication chamber and the first oil pump are connected head to tail, forming another safety oil circuit through the second outlet.

2. The fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine according to claim 1, characterized in that: The oil supply circuit further includes a common rail pipe, and the outlet of the oil outlet valve is connected to the inlet of the common rail pipe.

3. The fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine according to claim 2, characterized in that: The oil supply circuit also includes an injector; The outlet of the common rail pipe is connected to the inlet of the fuel injector.

4. The fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine according to claim 1, characterized in that: The cam mechanism includes a roller and a cam, wherein the roller is sleeved on the cam and the edge of the roller is in contact with the plunger, the drive shaft is transmission-connected with the cam, the drive shaft drives the cam, drives the roller to move, and further drives the plunger to move, and the lubrication chamber is used to lubricate the friction between the roller and the cam, and between the roller and the plunger.

5. The fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine according to claim 2, characterized in that: The plunger pump also includes an oil outlet passage, which is connected to the common rail pipe and the oil outlet valve; an angle α formed by an extension line of the oil outlet passage and a movement direction of the plunger in the plunger pump is in a range of 0°-18°.

6. The fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine according to claim 1, characterized in that: When the pressure value of the first valve chamber is greater than a first preset pressure value, the first outlet of the relief valve is opened; when the pressure value of the first valve chamber is greater than a second preset pressure value, the first outlet and the second outlet of the relief valve are opened simultaneously; The first preset pressure value is smaller than the second preset pressure value.

7. The fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine according to claim 1, characterized in that: A first bearing oil return passage and a second bearing oil return passage are provided between the lubrication cavity and the first oil pump, and are connected to the first bearing clearance and the second bearing clearance respectively.

8. The fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine according to claim 1, characterized in that: The number of the plunger pumps in the oil supply circuit is one or more.

9. The fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine according to claim 1, characterized in that: The first oil delivery pump is a vane pump, an external gear pump, an internal gear pump, a trochoid gear pump or an electric pump.

10. The fuel supply pump oil circuit system for a high-pressure common rail electronically controlled diesel engine according to claim 1, characterized in that: The first oil pump and the driving shaft are connected by a key; The key is a flat key, a semicircular key or a spline.

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