A dual fuel injector for an engine

Abstract

A dual fuel injector for an engine includes a main housing, an outer valve body connected to the main housing, an intermediate body, and a needle valve. The outer valve body has a first fuel injection orifice and a first valve seat. The intermediate body is disposed in a bore of the outer valve body in a translatable manner. The intermediate body has a second fuel injection orifice and a second valve seat. A first pressure chamber and a first control chamber are formed between the intermediate body and the outer valve body. The first fuel injection orifice is in communication with the first pressure chamber through the first valve seat. A first input passage is in communication with the first pressure chamber, and a first return passage is in communication with the first control chamber. The needle valve is disposed in a bore of the intermediate body in a translatable manner. A second pressure chamber and a second control chamber are formed between the needle valve and the intermediate body. The second fuel injection orifice is in communication with the second pressure chamber through the second valve seat. A second input passage is in communication with the second pressure chamber, and a second return passage is in communication with the second control chamber.

Description

Technical Field

[0001] This application relates to fuel injectors, and more particularly to dual-fuel injectors for engines. Background Technology

[0002] Dual-fuel engines utilizing both conventional and alternative fuels play a positive role in the rational use of energy and environmental control. However, the injectors in dual-fuel engines using gaseous fuels as alternative fuels, such as diesel-natural gas engines, cannot be used in dual-fuel engines using liquid fuels as alternative fuels. Therefore, there is a need for a dual-fuel injector for engines where both conventional and alternative fuels are liquid, and for a dual-fuel injector that can be used without modifying the engine or injector mounting interface, thus enabling the effective utilization of liquid alternative fuels. Summary of the Invention

[0003] In one aspect, the present invention provides a fuel injector for an engine. The fuel injector includes a main housing, an outer valve body connected to the main housing, the outer valve body having a first fuel nozzle and a first valve seat, and an intermediate body. The intermediate body is movably disposed within the inner cavity of the outer valve body. The intermediate body has a second fuel nozzle and a second valve seat. A first pressure chamber and a first control chamber are formed between the intermediate body and the outer valve body. The first fuel nozzle is connected to the first pressure chamber via the first valve seat, and has a first input channel connected to the first pressure chamber, a first return channel connected to the first control chamber, and a needle valve. The needle valve is movably disposed within the inner cavity of the intermediate body. A second pressure chamber and a second control chamber are formed between the needle valve and the intermediate body. The second fuel nozzle is connected to the second pressure chamber via the second valve seat, and has a second input channel connected to the second pressure chamber and a second return channel connected to the first control chamber. The second return channel of the two control chambers, wherein the intermediate body can translate relative to the outer valve body between a first intermediate body position and a second intermediate body position. When in the first intermediate body position, the intermediate body abuts against the first valve seat to block the fluid connection between the first pressure chamber and the first fuel nozzle. When in the second intermediate body position, the intermediate body is spaced apart from the first valve seat to connect the first pressure chamber and the first fuel nozzle. The needle valve can translate relative to the intermediate body between a first needle valve position and a second needle valve position. When in the first needle valve position, the needle valve abuts against the second valve seat to block the fluid connection between the second pressure chamber and the second fuel nozzle. When in the second needle valve position, the needle valve is spaced apart from the second valve seat to connect the second pressure chamber and the second fuel nozzle.

[0004] Preferably, the first input channel is formed in the outer valve body and arranged along the first radial direction of the outer valve body; the second input channel is formed in the outer valve body and arranged along the second radial direction of the outer valve body, and the second radial direction is offset relative to the first radial direction along the second circumferential direction of the outer valve body with the longitudinal axis of the fuel injector as the axis.

[0005] Preferably, the fuel injector according to the invention further includes a feed annular groove formed between the outer valve body and the intermediate body, a return annular groove offset axially relative to the feed annular groove, and a second control chamber communicating between the feed annular groove and the return annular groove. The second input channel includes a primary input section formed in the outer valve body and a secondary input section formed in the intermediate body. The outlet of the primary input section and the inlet of the secondary input section are respectively communicated to the feed annular groove, and the outlet of the secondary input section is communicated to the second pressure chamber. The secondary input section is arranged along a first radial direction of the outer valve body.

[0006] Preferably, the radial distance between the inlet of the secondary input section and the longitudinal axis of the fuel injector is greater than the radial distance between the outlet of the secondary input section and the longitudinal axis of the fuel injector, and the outlet of the secondary input section is located between the inlet of the secondary input section and the second fuel nozzle along the longitudinal axis, such that the secondary input section is inclined relative to the longitudinal axis and narrows towards the second fuel nozzle.

[0007] Preferably, the second return channel is formed in the outer valve body and arranged along the third radial direction, which is angularly offset relative to the first radial direction and the second radial direction along the third circumference of the outer valve body with the longitudinal axis of the fuel injector as the axis.

[0008] Preferably, the second reflux channel includes a primary reflux section formed in the intermediate body and a secondary reflux section formed in the outer valve body. The inlet of the primary reflux section is connected to the second control cavity, and the outlet of the primary reflux section and the inlet of the secondary reflux section are respectively connected to the reflux annular groove. The primary reflux section and the secondary reflux section are arranged along the third radial direction.

[0009] Preferably, the fuel injector according to the present invention further includes a first control channel communicating with the second input channel and the first control cavity, wherein the first control channel forms a first damping through hole between the second input channel and the first control cavity.

[0010] Preferably, the first control channel is arranged along the third radial direction.

[0011] Preferably, the inner cavity of the intermediate body has a guide inner surface, and the needle valve has a plurality of guide ridges that are parallel to the longitudinal axis of the fuel injector, translate in conjunction with the guide inner surface, and are distributed circumferentially. A connecting portion is formed between adjacent guide ridges, and a radial gap is formed between the connecting portion and the guide inner surface, the radial gap constituting a liquid channel.

[0012] Preferably, the guide ridge abuts against the guide inner surface of the intermediate body.

[0013] Preferably, the envelope surface of the guide ridge forms a tight translational fit with the cylindrical inner surface of the intermediate body cavity, so that the intermediate body provides guiding support for the needle valve.

[0014] Preferably, the fuel injector according to the invention further includes a first fuel inlet opening at the top of the main housing and a second fuel inlet opening at the side wall of the main housing, the second fuel inlet being located between the first fuel inlet and the first fuel nozzle.

[0015] Preferably, the fuel injector according to the invention further includes a return outlet opening into the housing, wherein the return outlet communicates with both the first return channel and the second return channel. Brief description of the attached figures

[0016] Figure 1 This is a perspective view of a dual-fuel injector for an engine according to one embodiment;

[0017] Figure 2 yes Figure 1 An exploded view of the fuel injector shown;

[0018] Figure 3 This is a schematic diagram showing the cross-sectional orientation of the interface between the fuel injector housing and valve body and other views.

[0019] Figure 4 yes Figure 1 The exploded partial cross-sectional view of the fuel injector shown illustrates the following: along Figure 3 The longitudinal section of AA shown;

[0020] Figure 5 yes Figure 1 The exploded partial cross-sectional view of the fuel injector shown illustrates the following: along Figure 3 The longitudinal section of BB is shown;

[0021] Figure 6 yes Figure 1 The exploded partial cross-sectional view of the fuel injector shown illustrates the following: along Figure 3 The longitudinal section of CC is shown.

[0022] Figure 7 yes Figure 1 A partial cross-sectional view of the fuel injector valve body shown;

[0023] Figure 8 yes Figure 1 The combined cross-sectional view of the fuel injector valve body shown is displayed by superimposing cross-sections along the first, second, and third radial directions;

[0024] Figure 9A yes Figure 8 Enlarged view of part 9A of the fuel injector valve body shown;

[0025] Figure 9B yes Figure 8 The image shows a magnified view (9B) of the valve body of the material injector.

[0026] Figure 10A yes Figure 2 An enlarged cross-sectional view of the fuel injector valve body shown, illustrating the section along... Figure 3 The longitudinal section of DD shown

[0027] Figure 10B yes Figure 10A Partial exploded view;

[0028] Figure 11 yes Figure 1 The enlarged front view sectional view of the fuel injector nozzle section is shown, in which the intermediate body and needle valve are both in the closed position;

[0029] Figure 12 yes Figure 1 The enlarged front sectional view of the fuel injector nozzle section is shown, with the intermediate body in the open position.

[0030] Figure 13 yes Figure 1 The image shows an enlarged front sectional view of the fuel injector nozzle portion, with the needle valve in the open position.

[0031] Figure label:

[0032] 90° vertical axis

[0033] 100 fuel injector

[0034] 102 Main housing

[0035] 104 subshells

[0036] 106 Valve body

[0037] 108 connecting holes

[0038] 110 Valve body cross-section

[0039] 111 First radial

[0040] 112 Second radial

[0041] 112a Second week

[0042] 113 Third radial

[0043] 113a Third week

[0044] 120 External Valve Body

[0045] 120a top surface

[0046] 122 First fuel nozzle

[0047] 123 First valve seat

[0048] 126 First pressure chamber

[0049] 127 First Control Channel

[0050] 129 First Control Chamber

[0051] 130 First Input Channel

[0052] 131 First Fuel Inlet

[0053] 140 First Return Channel

[0054] 150 intermediates

[0055] 152 Second fuel nozzle

[0056] 153 Second valve seat

[0057] 155 Feed ring groove

[0058] 155a First Inner Groove

[0059] 155b First outer slot

[0060] 156 Second pressure chamber

[0061] 157 Second Control Channel

[0062] 158 Reflux Circulator

[0063] 158a Second Inner Groove

[0064] 158b Second Outer Slot

[0065] 159 Second Control Chamber

[0066] 1501 First intermediate position

[0067] 1502 Second intermediate position

[0068] 160 Second Input Channel

[0069] 161 Second Fuel Inlet

[0070] 162 Primary Input Section

[0071] 162a Primary Input Segment Entry

[0072] 162b Primary Input Section Output

[0073] 1621a Radial distance between the primary input section inlet and the longitudinal axis

[0074] 1621b Radial distance between the primary input section outlet and the longitudinal axis

[0075] 164 Secondary Input Section

[0076] 164a Secondary Input Section Entry

[0077] 164b Secondary Input Section Output

[0078] Radial distance between the secondary input section inlet and the longitudinal axis of 1641a

[0079] Radial distance between the outlet of the secondary input section and the longitudinal axis of 1641b

[0080] 170 Second Return Channel

[0081] 172 Primary Reflux Section

[0082] 174 Secondary recirculation section

[0083] 176 Reflux outlet

[0084] 178 Return Channel

[0085] 180 needle valve

[0086] 182 Radial clearance

[0087] 184 Guide Ridge

[0088] 185 prismatic segments

[0089] 186 Connecting part

[0090] 1801 First needle valve position

[0091] 1802 Second needle valve position

[0092] 191 First Solenoid Valve

[0093] 192 Second Solenoid Valve

[0094] 193 First elastic element

[0095] 194 Second elastic element Detailed Implementation

[0096] It is understood that, in addition to the exemplary embodiments described herein, components of the embodiments generally described and illustrated in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the exemplary embodiments illustrated in the accompanying drawings and the following more detailed description are merely representative of exemplary embodiments and do not limit the scope of protection claimed by the embodiments.

[0097] References to “one embodiment,” “another embodiment,” or “embodiment” (or similar terms) in this specification mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment. Therefore, phrases such as “in one embodiment” or “in an embodiment” appearing throughout this specification do not necessarily refer to the same embodiment in general.

[0098] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to provide a thorough understanding of the embodiments. However, those skilled in the art will recognize that various embodiments can be practiced without one or more specific details or using other methods, components, materials, etc. In other instances, some or all known structures, materials, or operations may not be shown or described in detail.

[0099] like Figure 1 and 2 As shown, a dual-fuel injector 100 for an engine includes a main housing 102, a secondary housing 104 connected to the side of the main housing 102, and a valve body 106 connected to the main housing 102 along the longitudinal axis 90 of the fuel injector 100. A first fuel inlet 131 is formed on the main housing 102, and a second fuel inlet 161 is formed on the secondary housing 104. The fuel injector 100 also includes a first solenoid valve 191 coupled to the main housing 102 for controlling the first fuel injection, and a second solenoid valve 192 coupled to the secondary housing 104 for controlling the second fuel injection. The secondary housing 104 includes a plurality of mounting holes, such as bolt holes 108, for coupling with the engine. In this document, the term "coupled" refers to the direct or indirect connection or assembly between two or more independent components in the dual-fuel injector 100 of the present invention, including detachable connection or assembly between the two or more independent components, such as connection or assembly through threaded structure, mechanical tolerance fit structure, etc., and non-detachable connection or assembly between the two or more independent components, such as connection or assembly through welding, riveting, etc.

[0100] Figures 3 to 10B The internal structure of the fuel injector 100 is shown in perspective, plan view, sectional view and exploded view, respectively. Figure 8 yes Figure 1 The combined cross-sectional view of the fuel injector valve body shown indicates that... Figure 4 , Figure 5 and Figure 6 The cross-sections along the first, second, and third radial directions located on different planes are superimposed and displayed on the same plane. Figure 10A yes Figure 2 The longitudinal sectional view of valve body 106 shown, wherein the outer valve body 120 is along Figure 3 The cross-section shown in the BB direction, with the intermediate body 150 along... Figure 3 The cross-section along the DD direction shown is as follows: Figures 3 to 10B As shown, in one embodiment, the valve body 106 includes an outer valve body 120 coupled to the main housing 102, an intermediate body 150 movably disposed in the inner cavity of the outer valve body 120, and a needle valve 180 movably disposed in the inner cavity of the intermediate body 150. The outer valve body 120 has a first fuel nozzle 122 and a first valve seat 123. The intermediate body 150 has a second fuel nozzle 152 and a second valve seat 153. A first pressure chamber 126 and a first control chamber 129 are formed between the intermediate body 150 and the outer valve body 120. The first fuel nozzle 122 communicates with the first pressure chamber 126 through the first valve seat 123. A second pressure chamber 156 and a second control chamber 159 are formed between the needle valve 180 and the intermediate body 150. The second fuel nozzle 152 communicates with the second pressure chamber 156 through the second valve seat 153. The first fuel inlet 131 opens at the top of the secondary housing 104, and the second fuel inlet 161 opens at the side wall of the main housing 102. The second fuel inlet 161 is located between the first fuel inlet 131 and the first fuel nozzle 122. A first elastic element, such as a first helical spring 193, is disposed in the first control chamber 129, and a second elastic element, such as a second helical spring 194, is disposed in the second control chamber 159.

[0101] The fuel injector 100 includes a pair of first input channels 130 communicating with a first pressure chamber 126 and a first return channel 140 communicating with a first control chamber 129. The first input channels 130 are formed in the main housing 102 and the secondary housing 104, and are in fluid communication with the first fuel inlet 131. The first input channels 130 establish fluid communication between the first pressure chamber 126 and the first fuel inlet 131. The first return channel 140 is formed in the main housing 102, and establishes fluid communication between the first control chamber 129 and the first solenoid valve 191.

[0102] The fuel injector 100 also includes a pair of second input channels 160 communicating with the second pressure chamber 156 and a second return channel 170 communicating with the second control chamber 159. The second input channels 160 are formed in the main housing 102 and are in fluid communication with the second fuel inlet 161. The second input channels 160 constitute fluid communication between the second pressure chamber 156 and the second fuel inlet 161. The second return channel 170 is formed in the main housing 102 and the secondary housing 104, constituting fluid communication between the second control chamber 159 and the second solenoid valve 192.

[0103] A feed annular groove 155 and a return annular groove 158 offset along the longitudinal axis 90 relative to the feed annular groove 155 are formed between the outer valve body 120 and the intermediate body 150. The feed annular groove 155 includes a first inner groove 155a formed around the inner wall of the outer valve body 120 and a first outer groove 155b formed around the outer wall of the intermediate body 150 and aligned with the first inner groove 155a along the longitudinal axis 90. The return annular groove 158 includes a second inner groove 158a formed in and around the inner wall of the outer valve body 120 and a second outer groove 158b formed in and around the outer wall of the intermediate body 150 and aligned with the first inner groove 155a along the longitudinal axis 90. A second control chamber 159 communicates between the feed annular groove 155 and the return annular groove 158.

[0104] The second input channel 160 includes a pair of primary input sections 162 formed in the outer valve body 120 and a pair of secondary input sections 164 formed in the intermediate body 150. The inlet 162a of each primary input section 162 opens onto the top surface 120a of the outer valve body 120. The outlet 162b of each primary input section 162 and the inlet 164a of each secondary input section 164 are respectively connected to the feed annular groove 155. Figure 10A and Figure 10B As shown, the radial distance 1621a between the inlet 162a of the primary input section 162 and the longitudinal axis 90 of the fuel injector 100 is greater than the radial distance 1621b between the outlet 162b of the primary input section 162 and the longitudinal axis (90) of the fuel injector 100. That is, the outlet 162b of the primary input section 162 is closer to the longitudinal axis 90 than the inlet 162a, so that the primary input section 162 is inclined relative to the longitudinal axis 90 and narrows towards the direction of the second fuel nozzle 152.

[0105] The outlet 164b of each secondary input section 164 is connected to the second pressure chamber 156. The feed annular groove 155 and the second pressure chamber 156 are arranged at different heights along the longitudinal axis 90, such that the second pressure chamber 156 is located between the feed annular groove 155 and the second fuel nozzle 152. The radial distance 1641a between the inlet 164a of the secondary input section 164 and the longitudinal axis 90 of the fuel injector 100 is greater than the radial distance 1641b between the outlet 164b of the secondary input section 164 and the longitudinal axis (90) of the fuel injector 100, and the outlet 164b of the secondary input section 164 is located between the inlet 164a of the secondary input section 164 and the second fuel nozzle 152 along the longitudinal axis 90. In other words, the outlet 164b of the pair of secondary input sections 164 is closer to the longitudinal axis 90 than the inlet 164a, so that the secondary input sections 164 are inclined relative to the longitudinal axis 90 and narrowed towards the second fuel nozzle 152.

[0106] refer to Figures 3 to 6 As an example, a pair of first input channels 130 are arranged along a first radial direction 111 of the outer valve body 120. A pair of second input channels 160 are arranged along a second radial direction 112 of the outer valve body 120. The second radial direction 112 is offset relative to the first radial direction 111 along a second circumferential direction 112a of the outer valve body 120, about the longitudinal axis 90 of the fuel injector 100. A second return channel 170 is arranged along a third radial direction 113. The third radial direction 113 is offset relative to the first radial direction 111 along a third circumferential direction 113a of the outer valve body 120, about the longitudinal axis 90 of the fuel injector 100. The third circumferential direction 113a is opposite to the second circumferential direction 112a. A second input channel 160 and a first control channel 127 are also formed in the outer valve body 120. The second input channel 160 and the first control channel 127 communicate with a first control cavity 129. The first control channel 127 is arranged along the third radial direction 113. The first control channel 127 has an aperture that allows a pressure difference to be provided between the second input channel 160 and the first control cavity 129, thereby forming a damping through-hole between the second input channel 160 and the first control cavity 129. According to the above arrangement, a pair of first input channels 130, a pair of second input channels 160, and a second return channel 170 are all formed in the outer valve body 120. The structural space provided by the outer valve body 120 is effectively utilized, resulting in a compact overall structure for the fuel injector 100, which can be adapted to the external dimensions of existing engine housings, thus eliminating the need for substantial modifications to the existing engine and fuel injector mounting interfaces.

[0107] The second return channel 170 includes a primary return section 172 formed in the intermediate body 150 and a secondary return section 174 formed in the outer valve body 120. The inlet of the primary return section 172 is connected to the second control chamber 159, and the outlet of the primary return section 172 and the inlet of the secondary return section 174 are respectively connected to the return annular groove 158. The secondary return section 174 is arranged along the third radial direction 113. Figure 6 ).

[0108] The intermediate body 150 includes a second control channel 157 communicating with the second input channel 160 and the second control cavity 159. The second control channel 157 is arranged along a third radial direction 113. The second control channel 157 has an aperture that allows a pressure differential to be formed between the second input channel 160 and the second control cavity 159, thereby forming a damping through-hole between the second input channel 160 and the second control cavity 159.

[0109] The fuel injector 100 also includes a return outlet 176 opening on the side of the main housing 102, and a return passage 178 communicating between the return outlet 176, the first solenoid valve 191, and the second solenoid valve 192. The return passage 178 communicates with the corresponding first return passage 140 and second return passage 170 through the first solenoid valve 191 and the second solenoid valve 192.

[0110] In one embodiment, such as Figure 7 As shown, the inner cavity of the intermediate body 150 has a guiding inner surface, such as a cylindrical inner surface. The needle valve 180 includes prismatic segments 185 corresponding to the guiding inner surface of the intermediate body 150, thereby forming a plurality of circumferentially distributed guiding ridges 184 and connecting portions 186 between adjacent guiding ridges. The guiding ridges 184 abut against the guiding inner surface of the intermediate body 150, and the envelope of the guiding ridges 184 forms a tight translational fit with the cylindrical inner surface of the inner cavity of the intermediate body 150, so that the intermediate body 150 provides guiding support for the needle valve 180. Simultaneously, a radial gap 182 is formed between the connecting portion 186 and the guiding inner surface. The radial gap 182 constitutes a liquid passage. The radial gap 182 forms part of the second pressure chamber 156. After the second solenoid valve 192 is opened, the second fuel can pass through the radial gap 182 during its flow from the feed annular groove 155 into the second pressure chamber 156 and be ejected from the second fuel nozzle 152.

[0111] The intermediate body 150 can translate relative to the outer valve body 120 between a first intermediate body position 1501 and a second intermediate body position 1502. When in the first intermediate body position 1501, as... Figure 11 As shown, the intermediate body 150 abuts against and is close to the first valve seat 123 to block the fluid communication between the first pressure chamber 126 and the first fuel nozzle 122. When in the second intermediate body position 1502, as... Figure 12As shown, the intermediate body 150 is spaced apart from the first valve seat 123 to connect the first pressure chamber 126 and the first fuel nozzle 122. Independent of the translational movement of the intermediate body 150 relative to the outer valve body 120, the needle valve 180 can translate relative to the intermediate body 150 between a first needle valve position 1801 and a second needle valve position 1802. When in the first needle valve position 1801, as shown in FIG. 10, the needle valve 180 abuts against and is close to the second valve seat 153 to block the fluid communication between the second pressure chamber 156 and the second fuel nozzle 152. When in the second needle valve position 1802, as shown in FIG. 10, the needle valve 180... Figure 12 As shown, the needle valve 180 is spaced apart from the second valve seat 153 to connect the second pressure chamber 156 and the second fuel nozzle 152.

[0112] When the fuel injector 100 is in operation, a first fuel, such as liquid methanol, is supplied by a first high-pressure fuel pump through a first fuel inlet 131 and enters a first input channel 130 and a first pressure chamber 126. A second fuel, such as liquid diesel, is supplied by a second high-pressure fuel pump through a second fuel inlet 161 and enters a second input channel 160, a first return channel 140, a second return channel 170, a first control chamber 129, a second control chamber 159, a first control channel 127, a second control channel 157, and a second pressure chamber 156.

[0113] The first solenoid valve 191 is used to control the injection of the first fuel. Opening the first solenoid valve 191 allows the second fuel in the first control chamber 129 to flow through the first return channel 140 and the first solenoid valve 191 to the return outlet 176, resulting in the liquid pressure in the first control chamber 129 being lower than the liquid pressure in the first pressure chamber 126. Simultaneously, under the damping effect of the first control channel 127, a liquid pressure difference is formed between the first control chamber 129 and the first pressure chamber 126. When the liquid pressure difference between the first control chamber 129 and the first pressure chamber 126 applies a thrust to the intermediate body 150 in the direction away from the first nozzle 122, which is greater than the elastic force of the first elastic member 193, the intermediate body 150 is driven by the first fuel in the first pressure chamber 126, moving from position 1501 of the first intermediate body. Figure 11 ) Translate to position 1502 of the second intermediate body. Figure 12 Intermediate body 150, at second intermediate body position 1502, forms a connection between first pressure chamber 126 and first fuel nozzle 122, allowing first fuel to be ejected from first fuel nozzle 122 from fuel injector 100 to supply first fuel to engine on which fuel injector 100 is mounted. After first solenoid valve 191 closes, second fuel flows through first control channel 127 to first control chamber 129, causing pressure in first control chamber 129 to increase. When the pressure difference between first control chamber 129 and first pressure chamber 126 is less than the elastic force of first elastic member 193, intermediate body 150 returns to first intermediate body position 1501. Figure 11 The first pressure chamber 126 is closed to the first fuel nozzle 122, thereby stopping the first fuel from being ejected from the first fuel nozzle 122.

[0114] Independent of the control of the first solenoid valve 191, the second solenoid valve 192 is used to control the injection of the second fuel. Opening the second solenoid valve 192 allows the second fuel in the second control chamber 159 to flow through the second return channel 170 and the second solenoid valve 192 to the return outlet 176. This reduces the liquid pressure in the second control chamber 159 to less than the liquid pressure in the second pressure chamber 156. Simultaneously, under the damping effect of the second control channel 157, a liquid pressure difference is formed between the second control chamber 159 and the second pressure chamber 156. When the thrust applied to the needle valve 180 by the liquid pressure difference between the second control chamber 159 and the second pressure chamber 156 in the direction away from the second nozzle 152 is greater than the elastic force of the second elastic member 194, the needle valve 180 is driven by the second fuel in the second pressure chamber 156, moving from the first needle valve position 1801 (…). Figure 11 ) Move to the second needle valve position 1802 ( Figure 13 The needle valve 180, at its second needle valve position 1802, establishes communication between the second pressure chamber 156 and the second fuel nozzle 152, allowing second fuel to be ejected from the fuel injector 100 through the second fuel nozzle 152 to supply second fuel to the engine on which the fuel injector 100 is mounted. After the second solenoid valve 192 closes, the second fuel flows through the second control channel 157 to the second control chamber 159, increasing the pressure in the second control chamber 159. When the pressure difference between the second control chamber 159 and the second pressure chamber 156 is less than the elastic force of the second elastic member 194, the needle valve 180 resets to its first needle valve position 1801, closing the communication between the second pressure chamber 156 and the second fuel nozzle 152, thereby stopping the second fuel from being ejected from the second fuel nozzle 152. As described above, by independently and / or coordinatedly opening and closing the first solenoid valve 191 and the second solenoid valve 192, the injection or cessation of the first and second fuel can be controlled, thereby supplying the engine with the first and second fuel.

[0115] As used herein, unless otherwise expressly stated, the singular “one” and “a” can be interpreted to include the plural “one or more”.

[0116] This invention is for illustrative and descriptive purposes only and is not intended to be exhaustive or restrictive. Many modifications and variations will be apparent to those skilled in the art. The exemplary embodiments selected and described herein are intended to explain the principles and practical applications, enabling those skilled in the art to understand the various modifications suitable for different embodiments of the invention to achieve the desired specific technical effects.

[0117] Therefore, although illustrative exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the description is not restrictive, and those skilled in the art can make various other changes and modifications without departing from the scope of the invention or the inventive concept and implementation scheme.

Claims

1. A dual-fuel injector for an engine, characterized in that, The dual-fuel injector includes: main housing; An outer valve body connected to the main housing, the outer valve body having a first fuel nozzle and a first valve seat; An intermediate body is movably disposed within the inner cavity of the outer valve body. The intermediate body has a second fuel nozzle and a second valve seat. A first pressure chamber and a first control chamber are formed between the intermediate body and the outer valve body. The first fuel nozzle is connected to the first pressure chamber through the first valve seat. A first input channel connected to the first pressure chamber; A first return channel connected to the first control cavity; A needle valve is movably disposed within the inner cavity of the intermediate body. A second pressure chamber and a second control chamber are formed between the needle valve and the intermediate body. The second fuel nozzle is connected to the second pressure chamber through the second valve seat. A second input channel connected to the second pressure chamber; A second return channel connected to the second control cavity; The intermediate body is translatable relative to the outer valve body between a first intermediate body position and a second intermediate body position; when in the first intermediate body position, the intermediate body abuts against the first valve seat to block the fluid connection between the first pressure chamber and the first fuel nozzle; when in the second intermediate body position, the intermediate body is spaced apart from the first valve seat to connect the first pressure chamber and the first fuel nozzle. The needle valve can translate relative to the intermediate body between a first needle valve position and a second needle valve position; when in the first needle valve position, the needle valve abuts against the second valve seat to block the fluid connection between the second pressure chamber and the second fuel nozzle; when in the second needle valve position, the needle valve is spaced apart from the second valve seat to connect the second pressure chamber and the second fuel nozzle. The first input channel is formed in the outer valve body and arranged along the first radial direction of the outer valve body; the second input channel is formed in the outer valve body and arranged along the second radial direction of the outer valve body, and the second radial direction is offset relative to the first radial direction along the second circumferential direction of the outer valve body with the longitudinal axis of the fuel injector as the axis; The dual-fuel injector further includes a feed annular groove formed between the outer valve body and the intermediate body, a return annular groove offset axially relative to the feed annular groove, and a second control chamber communicating between the feed annular groove and the return annular groove. The second input channel includes a primary input section formed in the outer valve body and a secondary input section formed in the intermediate body. The outlet of the primary input section and the inlet of the secondary input section are respectively connected to the feed annular groove, and the outlet of the secondary input section is connected to the second pressure chamber. The secondary input section is arranged along the second radial direction of the outer valve body.

2. The dual-fuel injector as claimed in claim 1, characterized in that, The radial distance between the inlet of the secondary input section and the longitudinal axis of the fuel injector is greater than the radial distance between the outlet of the secondary input section and the longitudinal axis of the fuel injector. The outlet of the secondary input section is located between the inlet of the secondary input section and the second fuel nozzle along the longitudinal axis, such that the secondary input section is inclined relative to the longitudinal axis and narrows towards the second fuel nozzle.

3. The dual-fuel injector as claimed in claim 1, characterized in that, The second return channel is formed in the outer valve body and arranged along the third radial direction, which is offset relative to the first radial direction and the second radial direction along the third circumference of the outer valve body with the longitudinal axis of the fuel injector as the axis.

4. The dual-fuel injector as described in claim 3, characterized in that, The second reflux channel includes a primary reflux section formed in the intermediate body and a secondary reflux section formed in the outer valve body. The inlet of the primary reflux section is connected to the second control cavity, and the outlet of the primary reflux section and the inlet of the secondary reflux section are respectively connected to the reflux annular groove. The primary reflux section and the secondary reflux section are arranged along the third radial direction.

5. The dual-fuel injector as described in claim 3, characterized in that, It also includes a first control channel that connects the second input channel and the first control cavity, wherein the first control channel forms a first damping through hole between the second input channel and the first control cavity.

6. The dual-fuel injector as claimed in claim 5, characterized in that, The first control channel is arranged along the third radial direction.

7. The dual-fuel injector as claimed in claim 1, characterized in that, The inner cavity of the intermediate body has a guide inner surface, and the needle valve has a plurality of guide ridges that are parallel to the longitudinal axis of the fuel injector, translate in conjunction with the guide inner surface, and are distributed circumferentially. A connecting portion is formed between adjacent guide ridges, and a radial gap is formed between the connecting portion and the guide inner surface. The radial gap constitutes a liquid channel.

8. The dual-fuel injector as claimed in claim 7, characterized in that, The guide ridge abuts against the inner guide surface of the intermediate body.

9. The dual-fuel injector as claimed in claim 7, characterized in that, The envelope surface of the guide ridge forms a tight translational fit with the cylindrical inner surface of the intermediate body cavity, so that the intermediate body provides guiding support for the needle valve.

10. The dual-fuel injector as claimed in claim 1, characterized in that, It also includes a secondary housing connected to the side of the main housing, a first fuel inlet opening at the top of the secondary housing and a second fuel inlet opening at the side wall of the main housing, the second fuel inlet being located between the first fuel inlet and the first fuel nozzle.

11. The dual-fuel injector as claimed in claim 1, characterized in that, It also includes a reflux outlet opening into the main housing, wherein the reflux outlet is connected to the first reflux channel and the second reflux channel through their respective solenoid valve bodies.

Images