CN112443440A - Fuel injection unit - Google Patents
Fuel injection unit Download PDFInfo
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- CN112443440A CN112443440A CN201911160430.9A CN201911160430A CN112443440A CN 112443440 A CN112443440 A CN 112443440A CN 201911160430 A CN201911160430 A CN 201911160430A CN 112443440 A CN112443440 A CN 112443440A
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- fuel
- pressure
- oil pipe
- nozzle
- nozzle valve
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- 239000000446 fuel Substances 0.000 title claims abstract description 161
- 238000002347 injection Methods 0.000 title claims abstract description 69
- 239000007924 injection Substances 0.000 title claims abstract description 69
- 239000003921 oil Substances 0.000 claims abstract description 117
- 239000007921 spray Substances 0.000 claims abstract description 7
- 239000000295 fuel oil Substances 0.000 claims abstract description 6
- 238000005507 spraying Methods 0.000 claims abstract description 3
- 239000007788 liquid Substances 0.000 claims description 41
- 230000009471 action Effects 0.000 claims description 8
- 238000000926 separation method Methods 0.000 description 10
- 239000002828 fuel tank Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 5
- 230000005389 magnetism Effects 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
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- 238000001914 filtration Methods 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000003566 sealing material Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 230000008859 change Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 230000033001 locomotion Effects 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 230000005489 elastic deformation Effects 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 239000012808 vapor phase Substances 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000010420 art technique Methods 0.000 description 1
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- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000003502 gasoline Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 210000005239 tubule Anatomy 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
- F02M59/10—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/30—Controlling fuel injection
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
- F02M55/004—Joints; Sealings
- F02M55/005—Joints; Sealings for high pressure conduits, e.g. connected to pump outlet or to injector inlet
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
- F02M55/02—Conduits between injection pumps and injectors, e.g. conduits between pump and common-rail or conduits between common-rail and injectors
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
- F02M59/46—Valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
- F02M59/46—Valves
- F02M59/462—Delivery valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
- F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
- F02M61/18—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
- F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
- F02M61/20—Closing valves mechanically, e.g. arrangements of springs or weights or permanent magnets; Damping of valve lift
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
The utility model provides a fuel injection unit, includes a fuel pump, pressure oil pipe and fuel sprayer, the fuel sprayer includes a nozzle valve, a jet orifice with the nozzle valve intercommunication, and the fuel pump passes through pressure oil pipe with the fuel sprayer and is connected its characterized in that: the fuel pump provides pressure fuel oil, enters a pressure oil pipe, when the pressure in the oil pipe is higher than the opening pressure of the nozzle valve, the fuel oil is sprayed out, the pressure oil pipe comprises at least one flow limiting hole arranged at the front end of the pressure oil pipe so as to reduce the influence of pressure fluctuation in the cavity of the pressure oil pipe on the spraying precision, and the flow passage sectional area of the flow limiting hole is larger than the flow passage sectional area of a jet orifice of a fuel spray nozzle.
Description
Technical Field
The invention belongs to the technical field of engines, particularly relates to an electronic fuel injection device, and particularly relates to an electronic fuel injection system applied to a small engine.
Background
In recent years, an Electronic Fuel Injection system (EFI system for short) is rapidly applied and popularized due to its advantages of high comfort, energy saving, environmental protection, etc., and for a small engine system, taking a motorcycle as an example, it is a necessary trend that an Electronic Fuel Injection system gradually replaces a carburetor no matter the use performance or the emission regulation requirements.
The electronic fuel injection system senses the change of different working conditions and environments and the intention of a rider through various sensors, and provides the optimal fuel quantity and the optimal ignition advance angle for the engine in a precise and digital mode. At present, one of the widely applied electronic fuel injection technologies is a fuel supply pump-fuel injector mode of nozzle-end control metering represented by a BOSCH electronic fuel system, and the technology needs a plurality of devices including liquid supply, pressure stabilization, injection and the like, so that the system is complex, the power supply is difficult, and the system cost is high.
The other technical scheme is a pump end control metering mode, and the key advantages of the technology are that the system is small in size and flexible in arrangement, and the system is more suitable for small gasoline engines with compact structures and small available space. The pump end control metering mode generates high-pressure metering liquid through an external pulse type fuel pump, the high-pressure metering liquid is output by a pressure opening type fuel spray nozzle, and the fuel pump is generally connected with the fuel spray nozzle through a flexible pressure oil pipe. However, the system is greatly affected by pressure waves in the pipe and opening and closing pressure difference of the nozzle, and problems of slow closing of the nozzle or multiple opening of the nozzle, which are not stable, can occur, so that the residual pressure in the pipe is unstable, the flow of single-injection fuel is unstable, and the like. In addition, the pressure in the pipe is greatly influenced by the elastic quantity of the wall of the pressure oil pipe, and high-pressure fluid directly impacts the wall of the pressure oil pipe when passing through the pressure oil pipe, so that unstable injection pressure is easily caused, and the injection precision is influenced.
In summary, although the pump-end control metering method is simple in structure, the single injection precision problem is not well solved, and thus the method cannot be practically applied. Under the great trend of electric spraying of an engine system, the technical research of considering both the flow stability of the system and the simple structure of the system is very significant.
Disclosure of Invention
The invention aims to solve the problems of the pump end control metering mode fuel injection system, and aims to provide the pulse type fuel injection system which is simple in structure, good in adaptability, low in cost, stable in internal liquid pressure of the system and high in injection precision.
In order to achieve the purpose, the invention adopts the following technical scheme that the fuel injection unit comprises a fuel pump, a pressure oil pipe and a fuel injection nozzle, wherein the fuel pump is communicated with the fuel injection nozzle through the pressure oil pipe.
The fuel pump is a pulse type solenoid plunger pump, is controlled by PWM pulse signals and comprises a power part and a plunger pump assembly. The power part comprises a coil, an armature, a magnetizer and a magnetism isolating ring, wherein the armature comprises an armature oil duct which penetrates through the center and comprises a taper hole. The magnetizer and the armature are made of magnetic conductive materials, such as pure iron and the like, and the magnetism isolating ring is made of non-magnetic conductive materials, such as nonferrous metals or plastics and the like. The plunger pump assembly comprises a plunger, a plunger sleeve, an oil outlet valve, an oil inlet valve and a plunger spring. The plunger sleeve comprises an oil inlet hole, the oil inlet valve can be a slide valve consisting of the oil inlet hole and the plunger, the plunger sleeve is in sliding fit with the wall surface of the plunger to control the liquid flow passing through the oil inlet hole, and when the wall surface of the plunger completely covers the oil inlet hole, the oil inlet valve is closed. The oil outlet valve comprises a valve element, an oil outlet valve seat surface and an oil outlet valve spring, wherein the oil outlet valve seat surface and the oil outlet valve spring are positioned on the plunger sleeve, the oil outlet valve element can be a sphere, a cone or a flat plate and can be made of metal or ceramic materials, and the oil outlet valve seat surface can be a conical surface or a flat surface formed at the outlet of the plunger sleeve and is usually formed in a machining mode. The plunger, the plunger sleeve, the oil inlet valve and the oil outlet valve travel a pressure volume cavity, and the moving part of the plunger pump assembly causes the fuel pressure of the pressure volume cavity to change alternately in the reciprocating motion process to generate pulse type fuel injection. The moving part can be a plunger or directly an armature designed as a plunger sleeve.
The nozzle comprises a nozzle valve and an injection port communicated with the nozzle valve, the nozzle valve comprises a nozzle valve member, a nozzle valve seat and a nozzle valve spring, the opening state of the nozzle valve is determined by the combined action of the liquid pressure in the inner cavity of the pressure oil pipe and the spring force of the nozzle valve spring, and pressure fuel is sprayed out of the injection port in an atomized state when the nozzle valve is opened.
The nozzle valve may be a conventional pressure lift valve type nozzle (pop valve) having a sealing conical surface that is fitted to a conical surface of a nozzle valve seat, or another ball valve type nozzle having a multi-hemispheric nozzle member that is fitted to a conical surface of a nozzle valve seat through a spherical surface and sealed, and the injection port is located at one side of the nozzle valve to change the injection direction with ease.
The pressure oil pipe is a flexible thin pipe with the inner diameter not larger than 5mm, the liquid pressure in the inner cavity of the pressure oil pipe is not lower than 1/2 of the opening pressure of the nozzle valve in a non-jetting state, and the pressure oil pipe comprises at least one flow limiting hole. The flow limiting hole is arranged at the front end of the pressure oil pipe, the flow passage sectional area of the flow limiting hole is larger than the jet orifice flow passage sectional area of the oil nozzle, the fuel pump generates high-pressure liquid and enters the pressure oil pipe, when the liquid pressure in the pressure oil pipe is larger than the spring force of the nozzle valve spring, the nozzle valve is opened, and the high-pressure fuel is sprayed out from the jet orifice in a fog shape. When high-pressure liquid passes through the flow limiting hole, pressure fluctuation is reduced, energy fluctuation caused by impact of pressure on the pipe wall is effectively reduced, and meanwhile, enough liquid pressure in the pipe can be guaranteed, so that abnormal working states such as multiple opening of a nozzle and the like can be prevented in a wider flow and working frequency range, stable residual pressure is kept, and single fuel injection stability is improved.
Furthermore, the pressure oil pipe is provided with a first flow limiting hole and a second flow limiting hole along the flow direction of the high-pressure liquid, the flow limiting holes are respectively arranged at two ends of the pressure oil pipe, the aperture of each flow limiting hole is gradually reduced along the flow direction of the high-pressure liquid, and the flow passage sectional area of the second flow limiting hole is larger than that of the jet orifice. By the design, dynamic influence of pressure waves generated by the mechanical moving parts of the pump end and the nozzle end on the other end can be prevented, so that the stability of the liquid flow of the high-pressure oil pipe pumped by the pump end is improved, and the stability of the liquid flow sprayed by the nozzle is improved.
The two ends of the pressure oil pipe comprise a first quick joint and a second quick joint, and the pressure oil pipe and the quick joints can be connected into a whole in an injection molding mode. The first quick connector is located pressure oil pipe one end and comprises a first connector body and a first reverse buckle, and the second quick connector is located the other end of the pressure oil pipe and comprises a second connector body and a second reverse buckle. The oil nozzle of the fuel pump comprises a pump locking boss, the first connector body leads to the reverse buckle to be affected by the size of the pump locking boss to generate elastic deformation through axial thrust to be propped open, the connector body continues to move forwards, and when the connector moves to a certain position, the reverse buckle rebounds to be fastened with the pump locking boss, so that connection is guaranteed. The oil nozzle comprises a nozzle end locking boss, and the second quick connector is tightly matched and clamped with the nozzle end locking boss according to the same principle. The first quick connector is mutually sealed with the oil nozzle through elastic sealing materials, and the second quick connector is mutually sealed with the oil nozzle through elastic sealing materials.
The fuel injection unit also comprises an Engine Control Unit (ECU), the ECU gives drive pulses synchronously according to the fuel injection quantity demand and the stroke of the engine, the fuel pump is controlled by the ECU to supply fuel which is equal to or approximately equal to the fuel injection quantity injected by the nozzle to the pressure fuel pipe according to the self-metering mode, and the fuel quantity and the pressure in the pressure fuel pipe are kept basically unchanged through the metered average fuel flow and the pressure stabilization of the flow limiting hole.
The invention is described in further detail below with reference to the figures and specific embodiments.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of a fuel injection unit provided by the present invention.
Fig. 2 is a second schematic structural diagram of an embodiment of a fuel injection unit provided by the present invention.
Fig. 3 is a third schematic structural diagram of an embodiment of a fuel injection unit provided by the present invention.
Fig. 4 is a schematic structural diagram of an application example of the fuel injection unit provided by the present invention.
Detailed Description
The first embodiment of the present invention is schematically shown in fig. 1, and the fuel injection unit 1 includes a fuel pump 15, a pressure fuel pipe 2 and a fuel injector 3, and the fuel pump 15 and the fuel injector 3 are communicated through the pressure fuel pipe 2.
The fuel pump 15 is a pulse type solenoid plunger pump controlled by PWM pulse signal, and comprises a power part 4 and a plunger pump assembly 5. The power part 4 comprises a coil 101, an armature 114, a magnetizer 100, an inner magnetizer 116, a magnetism isolating ring 102 and an armature 114 chamber, wherein the armature 114 comprises an armature oil passage 115 which penetrates through the center and comprises a taper hole. The magnetizer 100, the inner magnetizer 116 and the armature 114 are made of a magnetic conductive material, such as pure iron, etc., and the magnetism isolating ring 102 is made of a non-magnetic conductive material, such as non-ferrous metal or plastic, etc.
The plunger pump assembly 5 includes a plunger 113, a plunger sleeve 111, an oil outlet valve 7, an oil inlet valve 6, and a plunger spring 112. The plunger sleeve 111 includes an oil inlet hole 104, the oil inlet valve 6 may be a slide valve composed of the oil inlet hole 104 and a plunger 113, the plunger sleeve 111 is slidably fitted to a wall surface of the plunger 113, the plunger 113 is a moving member that reciprocates relative to the plunger sleeve 111 under the action of a driving force and a plunger spring 112 to control a flow rate of liquid through the oil inlet hole 104, and the oil inlet valve 6 is closed when the wall surface of the plunger 113 completely covers the oil inlet hole 104. The oil outlet valve 7 comprises an oil outlet valve member 106, an oil outlet valve seat surface 105 and an oil outlet valve spring 118, wherein the oil outlet valve member 106 can be a sphere, a cone or a flat plate, and can be made of metal or ceramic, and the oil outlet valve seat surface 105 can be a conical surface formed at the outlet of the plunger sleeve 111, and can also be a flat surface, and is usually formed by machining. The plunger 113, the plunger sleeve 111, the oil inlet valve 6 and the oil outlet valve 7 travel a pressure volume cavity 119, and the liquid pressure in the pressure volume cavity 119 is changed alternately along with the opening and the closing of the oil inlet valve 6, so that pulse type fuel injection is generated.
Pressure oil pipe 2 is a flexible tubule that the internal diameter is not more than 5mm, and 2 both ends of pressure oil pipe include first quick-operation joint 8 and second quick-operation joint 9, quick-operation joint includes back-off 108 and is connected as an organic wholely through the mode of moulding plastics with pressure oil pipe 2. The fuel pump 15 includes one and goes out glib 110, it sets up between pressure volume cavity 119 and glib 110 to go out oil valve 7, and it includes a locking boss 109 to go out glib 110, and first joint body leads to the back-off to produce elastic deformation and strut by pump locking boss 109 size through axial thrust, continues to move forward when connecting body 8, when connecting 8 and moving to a certain position, back-off 108 kick-backs, with the mutual straining of pump locking boss 109, guarantees to be connected, first quick-operation joint 8 is through mutual sealing between elastic sealing material 120 and the glib 110. The oil nozzle 3 is connected and locked through a second quick connector 9 in the same quick connection mode, and sealing is achieved through sealing materials.
The cavity between the oil outlet valve 7 and the oil nozzle 3 is a high-pressure chamber 121, and valves at two ends in a static state are closed to ensure that certain liquid pressure exists in the high-pressure chamber 121. The front section of the high-pressure chamber 121 is provided with a flow limiting hole 122, the flow passage sectional area of the flow limiting hole 122 is larger than the flow passage sectional area of the injection port 212 of the oil nozzle 3, when high-pressure liquid passes through the flow limiting hole 122, pressure fluctuation is reduced, energy fluctuation caused by impact of pressure on a pipe wall is effectively reduced, and meanwhile, enough liquid pressure in the pipe can be guaranteed to meet injection requirements.
The operation of the fuel injection unit 1 described above is as follows:
when the armature 114 is at a rest position, the plunger 113 is pressed against the armature 114 under the action of the plunger spring 112, the upper end face of the armature 114 abuts against the upper end cover, the oil inlet hole 104 is opened, fuel from a fuel tank (not shown in the figure) enters from the oil inlet channel 103, a part of the fuel enters the pressure volume cavity 119 through the oil inlet hole 104, the other part of the fuel enters the armature 114 chamber through the oil passing hole 123 and then enters the oil return channel 124 through the armature oil channel 115, and the oil return nozzle 117 is communicated with the top of the fuel tank.
The coil 101 of the power section 4 can be driven by an electric signal of PWM type. Under the condition of applying voltage, an electromagnetic field forms a magnetic gap at the magnetism isolating ring 102, the armature 114 pushes the plunger 113 to move downwards under the action of the magnetic gap field, the plunger 113 compresses the plunger spring 112, when the wall surface of the plunger 113 completely covers the oil inlet hole 104, fuel in the pressure volume cavity 119 is compressed and pushes away the oil outlet valve piece 106 of the oil outlet valve 7 to flush into the high-pressure chamber 121, when high-pressure liquid passes through the flow limiting hole 122, a liquid pressure wave is weakened, the pressure liquid fills the rear volume of the high-pressure chamber 121 in a stable state, and when the fuel pressure of the high-pressure chamber 121 is higher than the preset opening pressure of the fuel injection nozzle 3, the fuel is injected out through the fuel injection nozzle 3 in a stable injection quantity.
When the voltage applied to both ends of the coil 101 by the PWM drive signal disappears or is about to disappear, and the electromagnetic force, the fuel pressure, the plunger spring force, the inertia force, and the like acting on the plunger 113 are balanced with each other, the plunger 113 stops moving downward, the fuel pressure in the pressure volume chamber 119 and the high pressure chamber 121 starts to decrease, and the fuel injection nozzle 3 stops injecting the fuel when the fuel pressure in the high pressure chamber 121 is lower than a predetermined pressure (a nozzle opening required pressure). At the same time, the plunger 113 starts to move upward by the plunger spring 112 and returns to the initial position, the delivery valve 7 is closed, the fuel remaining in the high pressure chamber 121 maintains a certain pressure, the fuel pressure in the pressure volume 119 drops sharply, and when the inlet hole 104 is opened again, the fuel rapidly enters the pressure volume 119 again from the inlet passage 103, and waits for the next compression cycle.
As the plunger 113 and armature 114 travel upward, fuel is carried along to the return 124. During the reciprocating motion of the armature 114, due to the function of the armature 114 oil channel with the taper hole, the net flow rate of the fuel flow caused by the armature 114 is from the oil inlet channel 103 to the oil return channel 124, and such flow can continuously take away the heat generated by the power portion 4, so as to ensure the normal operation of the injection unit.
The structure of the second embodiment of the present invention is schematically shown in fig. 2, and one difference from the structure of the first embodiment is that a first restriction hole 122 and a second restriction hole 200 are arranged in the high pressure chamber 121 along the flow direction of the high pressure liquid, the restriction holes 122 are respectively arranged at two ends of the pressure oil pipe 2, the aperture of the restriction holes (122, 200) decreases in the flow direction of the high pressure liquid, and the cross-sectional area of the flow passage of the second restriction hole 200 is larger than that of the injection port 212. The present embodiment is different from the first embodiment in that the oil nozzle 3 is a pressure-opening ball valve nozzle, and the ball valve nozzle 3 includes a nozzle valve seat 204, a nozzle valve member 202, and a nozzle valve spring 203. The nozzle valve seat 204 includes a tapered surface 204a that fits the spherical surface of the nozzle valve element 202, and the nozzle valve element 202 is pressed against the tapered surface 204a by the spring force of the nozzle valve spring 203 to form a seal, and when the internal pressure is increased gradually to the opening pressure, the nozzle valve element 202 is separated from the seat tapered surface 204a, and the nozzle valve 3 is opened. The filter 205 is disposed at the front end of the nozzle valve 3, and the high-pressure fuel enters the fuel injection nozzle 3 after passing through the filter 205, thereby effectively preventing the valve element 202 and the injection port 212 of the fuel injection nozzle 3 from affecting the injection accuracy or the spray state due to dirt blockage. The present embodiment is different from the first embodiment in that the fuel injection unit 1 is integrated with an oil-gas separation device 10, which is connected in series between the oil inlet channel 103 and the oil return nozzle 117 and includes a vapor-liquid separation chamber 208 and an oil inlet chamber 209 that are communicated with each other. The gas-liquid separation chamber 208 is a space having a certain volume and includes a gas discharge bubble nozzle 207 provided at the top. The fuel inlet chamber 209 includes a fuel inlet nozzle 206 and a filtering device 210, and the fuel enters from the fuel inlet nozzle 206, is filtered by the filtering device 210 and then enters the fuel inlet passage 103, so as to ensure that the fuel in the fuel pump 15 has no dirt which affects the injection precision.
The operation of the fuel injection unit 1 described above is substantially identical to that of the first embodiment, and the main process is as follows.
Fuel in the fuel tank flows into the fuel inlet chamber 209 through the fuel inlet nozzle 206 and is filled, the fuel flows into the fuel pump 15 from the fuel inlet passage 103 after being filtered by the filter screen device 210, and gas in the fuel inlet chamber 209 enters the gas-liquid separation chamber 208 through the exhaust passage 211. When the power part 4 is electrified, the armature 114 pushes the plunger 113 to move downwards under the action of the magnetic field, the oil inlet valve 6 is closed in the process, the oil outlet valve 7 is opened along with the increase of the liquid pressure in the pressure volume cavity 119, the fuel oil enters the high-pressure chamber 121 and passes through the first flow limiting hole 122 to form a relatively stable liquid flow, and when the high-pressure liquid passes through the second flow limiting hole 200, the liquid pressure wave tends to be stable. The armature 114 continues to push the plunger 113 downward, the pressure in the high pressure chamber 121 continues to rise, and when the fuel pressure in the high pressure chamber 121 becomes higher than the spring force of the preset nozzle valve spring 203, the nozzle valve 3 opens, and fuel is injected through the injection port 212 in a stable injection amount.
When the pulsed drive signal is or is about to disappear, the plunger 113 stops moving downward, at which time the pressure in the high-pressure chamber 121 starts to drop, and the nozzle valve 3 is closed by the valve spring force. The plunger 113 pushes the armature 114 to move in the opposite direction under the action of the plunger spring 112. The outlet valve 7 is then closed and the pressure chamber 121 holds fuel at a pressure ready for the next injection. With the inlet valve 6 re-opened, the fuel filtered by the screen is rapidly replenished into the pressure volume 119, waiting for the next cycle.
During the upward movement of the plunger 113 and the armature 114, the fuel is carried to the oil return channel and enters the gas-liquid separation chamber 208 through the oil return nozzle 117, when the vapor-phase substance and the liquid-phase substance occupy the space of the gas-liquid separation chamber at the same time, in a static state, the vapor-phase substance occupies the upper space of the gas-liquid separation chamber, the liquid-phase substance occupies the lower space of the gas-liquid separation chamber, therefore, the gas in the gas-liquid separation chamber 208 is discharged from the end of the air discharge bubble nozzle 207, and the lower clean fuel enters the oil inlet chamber 209 from the air discharge channel 211.
Fig. 3 shows a third structure of an embodiment of the fuel injection unit 1 according to the present invention, which is different from the second structure of the fuel injection unit 1 according to the present invention in that the fuel injector 3 is a poppet-type nozzle (poppet valve) and includes a nozzle stem 301, a nozzle spring 300 and a nozzle valve seat 302, and the nozzle valve seat 302 and the nozzle stem 301 are sealed by the tapered surfaces (303, 304). The oil nozzle 3 can be locked at the joint of the pressure oil pipe 2 by means of threads 305 and sealed by an end face seal 306.
As shown in fig. 4, a schematic structural diagram of an application example of the fuel injection unit 1 provided by the present invention includes a fuel tank 11, a fuel injection unit 1, an ECU control unit 12 and an intake joint 13. The fuel injection unit 1 comprises a fuel pump 15, a pressure fuel line 2 and a fuel injector 3. The fuel tank 11 includes a fuel outlet connector 400 disposed at the bottom and a fuel return connector 402 disposed at the top of the fuel tank 11, the fuel outlet connector 400 is connected to the fuel inlet nozzle 206 of the fuel pump 15, and the fuel return connector 402 is connected to the air discharge nozzle 207 of the fuel pump 15. The upper end of the fuel outlet connector 400 is provided with a pen-shaped coarse filter 401 which is arranged in the fuel tank 11 and is used for coarse filtering fuel entering the fuel outlet connector. The oil nozzle 3 is mounted on the air inlet joint 13, and the spray hole of the nozzle is arranged in a mode that the spray is approximately positioned at the center of the air inlet passage of the engine.
The working process of the above application example is as follows,
after coarse filtration, the fuel oil flows out from the oil outlet connector 400 under the action of gravity and enters the fuel pump 15 from the oil inlet nozzle 206. When the vehicle engine gives the fuel injection quantity demand and the stroke, the ECU control unit 12 synchronously gives the driving pulse according to the self-metering mode, the fuel pump 15 receives the driving signal given by the ECU control unit 12, the fuel pump 15 generates high-pressure fuel, and the fuel which is equal to or approximately equal to the fuel injection flow of the nozzle is supplied to the pressure fuel pipe 2 through the flow limiting hole 122 (shown in figure 1). In the process, part of the fuel flows back from the oil return nozzle 117 (shown in fig. 1), the clean fuel returns to the oil inlet channel 103 after passing through the oil-gas separation chamber 208 (shown in fig. 2), and the gas part is discharged from the exhaust bubble nozzle 207 and takes away part of the heat, so that the fuel pump 15 works more stably.
The above examples are only for illustrating the essence of the present invention, but not for limiting the present invention. Any modifications, simplifications, or other alternatives made without departing from the principles of the invention are intended to be included within the scope of the invention.
The present invention is not concerned with parts which are the same as or can be implemented using prior art techniques.
Claims (7)
1. The utility model provides a fuel injection unit, includes a fuel pump, pressure oil pipe and fuel sprayer, the fuel sprayer includes a nozzle valve, a jet orifice with the nozzle valve intercommunication, and the fuel pump passes through pressure oil pipe with the fuel sprayer and is connected its characterized in that: the fuel pump provides pressure fuel oil, enters a pressure oil pipe, when the pressure in the oil pipe is higher than the opening pressure of the nozzle valve, the fuel oil is sprayed out, the pressure oil pipe comprises at least one flow limiting hole arranged at the front end of the pressure oil pipe so as to reduce the influence of pressure fluctuation in the cavity of the pressure oil pipe on the spraying precision, and the flow passage sectional area of the flow limiting hole is larger than the flow passage sectional area of a jet orifice of a fuel spray nozzle.
2. The fuel injection unit of claim 1, wherein: the high-pressure liquid flow limiting device comprises a first limiting hole and a second limiting hole, wherein the limiting holes are arranged at two ends of a pressure oil pipe, and the hole diameter of each limiting hole is gradually reduced along the flow direction of high-pressure liquid.
3. The fuel injection unit of claim 2, wherein: the pressure oil pipe is a flexible thin pipe with the inner diameter not larger than 5mm, and the liquid pressure in the inner cavity of the pressure oil pipe is not lower than 1/2 of the opening pressure of the nozzle valve in a non-jetting state.
4. The fuel injection unit of claim 4, wherein: the nozzle valve includes a nozzle valve member, a nozzle valve seat and a nozzle valve spring, and the opening state of the nozzle valve is determined by the combined action of the liquid pressure in the pressure oil pipe and the spring force of the nozzle valve spring, and when the nozzle valve is opened, the pressure fuel is atomized and sprayed from the injection port.
5. A fuel injection unit as set forth in claim 3 wherein: the fuel pump is a solenoid plunger pump controlled by a PWM pulse signal.
6. The fuel injection unit as set forth in one of claim 6, characterized in that: the fuel pump fuel supply flow rate is determined by its single pulse fuel supply and pump operating pulse frequency.
7. The fuel injection unit as set forth in one of claims 1-7, characterized in that: the fuel pump is controlled by the ECU to provide fuel to the pressure fuel pipe in a self-metering mode, wherein the fuel flow is equal to or approximately equal to the fuel flow injected by the nozzle.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
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| CN201910824378 | 2019-09-02 | ||
| CN2019108243786 | 2019-09-02 |
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| CN201922040076.8U Active CN211819757U (en) | 2019-09-02 | 2019-11-23 | Fuel injection unit |
| CN201911160430.9A Pending CN112443440A (en) | 2019-09-02 | 2019-11-23 | Fuel injection unit |
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| CN201922040076.8U Active CN211819757U (en) | 2019-09-02 | 2019-11-23 | Fuel injection unit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN211819757U (en) * | 2019-09-02 | 2020-10-30 | 福爱电子(贵州)有限公司 | Fuel injection unit |
| CN113153601B (en) * | 2021-05-08 | 2022-06-28 | 重庆红江机械有限责任公司 | Stabilizing device convenient for measuring oil injection quantity of oil injector |
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|---|---|
| CN211819757U (en) | 2020-10-30 |
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