Combined dual fuel injector

Abstract

A combined type dual-fuel injector is used for a dual-fuel engine, and the improved structure of the combined type dual-fuel injector can optimize the manufacturing process. The combined dual-fuel injector comprises a main shell, an outer valve body connected to the main shell, a middle body and a needle valve. The outer valve body is provided with a first fuel nozzle and a first valve seat. The middle body comprises an upper section and a lower section which are assembled into a whole. The middle body is arranged in an inner cavity of the outer valve body in a translational motion mode. The lower section is provided with a second fuel nozzle and a second valve seat. A first pressure cavity is formed between the lower section and the outer valve body. A first control cavity is formed between the upper section and the outer valve body. The first fuel nozzle communicates with the first pressure cavity through the first valve seat. The needle valve is arranged in an inner cavity of the middle body in a translational motion mode. A second pressure cavity and a second control cavity are formed between the needle valve and the middle body. And the second fuel nozzle is communicated with the second pressure cavity through the second valve seat.

Description

Technical Field

[0001] The present application relates to a fuel injector, and more particularly to a combined dual-fuel injector for a dual-fuel engine. Background Art

[0002] Dual-fuel engines using traditional fuels and alternative fuels play a positive role in the rational use of energy and environmental control. The internal structure of current dual-fuel injectors is complex, resulting in high manufacturing difficulty and cost. Therefore, it is necessary to provide a dual-fuel injector with an improved structure that can be manufactured without using special equipment and processes while meeting the functions of the dual-fuel injector itself. Summary of the Invention

[0003] In one aspect, the present utility model provides a combined fuel injector. The dual-fuel injector includes: a main housing (5102); an outer valve body (5120) connected to the main housing, the outer valve body having a first fuel injection port (5122) and a first valve seat (5123); an intermediate body (5150) movably disposed in the inner cavity of the outer valve body, the intermediate body including an upper segment (5150A) and a lower segment (5150B), the lower segment (5150B) having a second fuel injection port (5152) and a second valve seat (5153), a first pressure chamber (5126) being formed between the lower segment (5150B) and the outer valve body, a first control chamber (5129) being formed between the upper segment (5150A) and the outer valve body, the first fuel injection port communicating with the first pressure chamber through the first valve seat; a needle valve (5180) movably disposed in the inner cavity of the intermediate body, a second pressure chamber (5156) and a second control chamber (5159) being formed between the needle valve and the intermediate body, the second fuel injection port communicating with the second pressure chamber through the second valve seat; wherein the intermediate body can move relative to the outer valve body between a first intermediate position and a second intermediate position; when in the first intermediate position, the intermediate body abuts against the first valve seat to block the fluid connection between the first pressure chamber and the first fuel injection port; when in the second intermediate position, the intermediate body is spaced apart from the first valve seat to connect the first pressure chamber and the first fuel injection port; the needle valve can move 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 injection port; 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 injection port.

[0004] Preferably, the upper segment and the lower segment are assembled to form the intermediate body, and a fluid seal is formed between the upper segment and the lower segment. Preferably, the upper segment includes an axially extending sleeve portion (51501A), and the lower segment includes the axially extending lower protrusion (51501B), and the sleeve portion is coupled to the lower protrusion. Preferably, the inner diameter of the sleeve portion is smaller than the outer diameter of the lower protrusion.

[0005] Preferably, a first sealing interface (5151A) and a second sealing interface (5151B) are formed between the sleeve portion and the lower protrusion, wherein the first sealing interface is formed between the outer sidewall of the lower protrusion and the inner sidewall of the sleeve portion, and the second sealing interface is formed between the shoulder of the lower segment and the end wall of the sleeve portion. Preferably, the upper segment and the lower segment can be assembled in a plurality of relative positions in the circumferential direction. Preferably, the upper segment (5150A) forms an upper inner bore (5154A), and the lower segment forms a lower inner bore (5154B), and the upper inner bore and the lower inner bore constitute the inner bore of the intermediate body.

[0006] The following provides a detailed description of specific examples in conjunction with the drawings to further illustrate the technical solutions of the present invention. Description of the Drawings

[0007] Figure 1 is a perspective view of a dual fuel injector for an engine according to an embodiment;

[0008] Figure 2 is Figure 1 an exploded view of the fuel injector shown;

[0009] Figure 3 is Figure 1 a schematic diagram of the corresponding sectional orientation of the docking interface between the housing and the valve body of the fuel injector shown and other views;

[0010] Figure 4 is Figure 1 a partial exploded sectional view of the fuel injector shown, showing a longitudinal section along Figure 3 A-A shown;

[0011] Figure 5 is Figure 1 a partial exploded sectional view of the fuel injector shown, showing a longitudinal section along Figure 3 B-B shown;

[0012] Figure 6 is Figure 1 a partial exploded sectional view of the fuel injector shown, showing a longitudinal section along Figure 3 C-C shown;

[0013] Figure 7Is Figure 1 Partial sectional view of the fuel injector valve body shown;

[0014] Figure 8 Is Figure 1 Combined sectional view of the fuel injector valve body shown, with the sections along the first, second, and third radial directions superimposed and displayed;

[0015] Figure 9A Is Figure 8 Enlarged view of part 9A of the fuel injector valve body shown;

[0016] Figure 9B Is Figure 8 Enlarged view of part 9B of the fuel injector valve body shown;

[0017] Figure 10A Is Figure 2 Enlarged sectional view of a part of the fuel injector valve body shown, showing the longitudinal section along Figure 3 The longitudinal section D - D shown

[0018] Figure 10B Is Figure 10A Partial exploded view of the fuel injector shown;

[0019] Figure 10C Figure 10A Exploded view of the fuel injector intermediate body shown;

[0020] Figure 10D Is Figure 10A Sectional view and partial enlarged view of the fuel injector intermediate body in the assembled state shown;

[0021] Figure 11 Is Figure 1 Enlarged front sectional view of the fuel injection nozzle part of the fuel injector shown, where the intermediate body and the needle valve are both in the closed position;

[0022] Figure 12 Is Figure 1 Enlarged front sectional view of the fuel injection nozzle part of the fuel injector shown, where the intermediate body is in the open position;

[0023] Figure 13 Is Figure 1 Enlarged front sectional view of the fuel injection nozzle part of the fuel injector shown, where the needle valve is in the open position.

[0024] Reference numerals

[0025] 590 Longitudinal axis

[0026] 5100 Fuel injector

[0027] 5102 Main housing

[0028] 5104 secondary housing

[0029] 5106 valve body

[0030] 5108 connecting hole

[0031] 5110 valve body cross-section

[0032] 5111 first radial direction

[0033] 5112 second radial direction

[0034] 5112a second circumferential direction

[0035] 5113 third radial direction

[0036] 5113a third circumferential direction

[0037] 5120 outer valve body

[0038] 5120a top surface

[0039] 5122 first fuel nozzle

[0040] 5123 first valve seat

[0041] 5126 first pressure chamber

[0042] 5127 first control channel

[0043] 5129 first control chamber

[0044] 5130 first input channel

[0045] 5131 first fuel inlet

[0046] 5140 first return channel

[0047] 5150 intermediate body

[0048] 5150A upper segment

[0049] 5150B lower segment

[0050] 51501A sleeve portion

[0051] 51501B lower protruding portion

[0052] 51501C shoulder

[0053] 5151A first sealing interface

[0054] 5151B second sealing interface

[0055] 5152 second fuel nozzle

[0056] 5153 Second valve seat

[0057] 5154A Upper inner bore

[0058] 5154B Lower inner bore

[0059] 5155 Feed ring groove

[0060] 5155a First inner groove

[0061] 5155b First outer groove

[0062] 5156 Second pressure chamber

[0063] 5157 Second control channel

[0064] 5158 Return flow ring groove

[0065] 5158a Second inner groove

[0066] 5158b Second outer groove

[0067] 5159 Second control chamber

[0068] 51501 First intermediate position

[0069] 51502 Second intermediate position

[0070] 5160 Second input channel

[0071] 5161 Second fuel inlet

[0072] 5162 Primary input section

[0073] 5162a Primary input section inlet

[0074] 5162b Primary input section outlet

[0075] 51621a Radial distance between the primary input section inlet and the longitudinal axis

[0076] 51621b Radial distance between the primary input section outlet and the longitudinal axis

[0077] 5164 Secondary input section

[0078] 5164a Secondary input section inlet

[0079] 5164b Secondary input section outlet

[0080] 51641a Radial distance between the secondary input section inlet and the longitudinal axis

[0081] 51641b Radial distance between the secondary input section outlet and the longitudinal axis

[0082] 5170 Second reflux channel

[0083] 5172 Primary reflux section

[0084] 5174 Secondary reflux section

[0085] 5176 Reflux outlet

[0086] 5178 Reflux channel

[0087] 5180 Needle valve

[0088] 5182 Radial clearance

[0089] 5184 Guide ridge

[0090] 5185 Prismatic segment

[0091] 5186 Connecting part

[0092] 51801 First needle valve position

[0093] 51802 Second needle valve position

[0094] 5191 First solenoid valve

[0095] 5192 Second solenoid valve

[0096] 5193 First elastic member

[0097] 5194 Second elastic member Detailed implementation manners

[0098] It can be understood that, except for the described exemplary embodiments, the components of the embodiments generally described and illustrated in the accompanying drawings herein can be arranged and designed in various different settings. Therefore, the exemplary embodiments represented in conjunction with the accompanying drawings and the following more detailed description are only representatives of the exemplary embodiments and do not limit the scope of the embodiments claimed.

[0099] References in this specification to "one embodiment", "another embodiment" or "an embodiment" (or similar terms) mean that the particular features, structures or characteristics described in connection with that embodiment are included in at least one embodiment. Thus, the phrases "in one embodiment" or "in an embodiment" and the like that appear throughout this specification do not necessarily all refer to the same embodiment.

[0100] In addition, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a comprehensive understanding of the embodiments. However, those skilled in the art will understand that various embodiments may be practiced without one or more of the specific details or by using other methods, components, materials, etc. In other cases, some or all of the known structures, materials, or operations may not be shown or described in detail.

[0101] As Figure 1 and 2 shown, a combined dual fuel injector 5100 includes a main housing 5102, a secondary housing 5104 connected to the side of the main housing 5102, and a valve body 5106 connected to the main housing 5102 along the longitudinal axis 590 of the fuel injector 5100. A second fuel inlet 5161 is formed on the main housing 5102, and a first fuel inlet 5131 is formed on the secondary housing 5104. The fuel injector 5100 further includes a first solenoid valve 5191 coupled to the main housing 5102 for controlling the first fuel injection, and a second solenoid valve 5192 coupled to the secondary housing 5104 for controlling the second fuel injection. The secondary housing 5104 includes a plurality of mounting holes for coupling to the main housing, such as bolt holes 5108. In this document, the term "coupled" refers to the direct or indirect connection or assembly method between two or more independent components in the novel dual fuel injector 5100, including the detachable connection and assembly between the two or more independent components, such as connection and assembly by means of a threaded structure, a mechanical tolerance fit structure, etc., and also includes the non-detachable connection and assembly between the two or more independent components, such as connection and assembly by means of welding, riveting, etc.

[0102] Figures 3 to 10C The internal structure of the fuel injector 5100 is shown in a perspective view, a plan view, a sectional view, and an exploded view respectively, where Figure 8 is Figure 1 the combined sectional view of the fuel injector valve body shown, and the sections along the first, second, and third radial directions located in different planes shown in Figure 4 , Figure 5 and Figure 6 are superimposed and shown in the same plane. Figure 10A is Figure 2 the longitudinal sectional view of the valve body 5106 shown, where the outer valve body 5120 is sectioned along the B - B direction shown in Figure 3 , and the intermediate body 5150 is sectioned along the D - D direction shown in Figure 3 .

[0103] Refer to Figure 10C and Figure 10D, the intermediate 5150 includes an upper segment 5150A and a lower segment 5150B. The upper segment 5150A has an upper inner bore 5154A. The lower segment 5150B may have an inner bore 5154B. The upper inner bore 5154A and the lower inner bore 5154B constitute the inner bore of the intermediate 5150. The upper inner bore 5154A and the lower inner bore 5154B may both be cylindrical cavities.

[0104] In one example, the upper segment 5150A and the lower segment 5150B can be fitted in a plurality of relative positions circumferentially. Therefore, the step of aligning in a certain specific direction between the upper segment 5150A and the lower segment 5150B is eliminated, improving the assembly efficiency.

[0105] In one example, the upper segment 5150A and the lower segment 5150B can be an interference fit, thereby forming a fluid seal between the upper inner bore 5154A and the lower inner bore 5154B. Therefore, a fluid seal can be formed between the upper segment 5150A and the lower segment 5150B. The upper segment 5150A and the lower segment 5150B form an intermediate body after assembly, and the intermediate body can be disposed translationally in the inner cavity of the outer valve body 5120. The upper segment 5150A includes a sleeve portion 51501A extending along the axis 590. The lower segment 5150B includes a lower protrusion 51501B extending along the axis 590 and a shoulder 51501C surrounding the lower protrusion 155B. The sleeve portion 51501A and the lower protrusion 51501B form a coupling connection. The inner diameter of the sleeve portion 51501A is slightly smaller than the outer diameter of the lower protrusion 51501B. Therefore, the upper segment 5150A and the lower segment 5150B are assembled to form an intermediate body through an interference fit between the sleeve portion 51501A and the lower protrusion 51501B.

[0106] Continue to refer to Figure 10C and Figure 10D , in some examples, a first sealing interface 5151A and a second sealing interface 5151B are formed between the upper segment 5150A and the lower segment 5150B. Each of the sealing interfaces 5151A, 5151B constitutes a fluid sealing interface. The first sealing interface 5151A is formed between the outer side wall of the lower protrusion and the inner side wall of the sleeve portion, and the second sealing interface 5151B is formed between the shoulder of the segment and the end wall of the sleeve portion, thereby constituting a tight and fluid-tight coupling between the upper segment 5150A and the lower segment 5150B.

[0107] As Figures 3 to 10DAs shown, in one embodiment, the valve body 5106 includes an outer valve body 5120 coupled to the main housing 5102, an intermediate body 5150 movably disposed in the inner cavity of the outer valve body 5120, and a needle valve 5180 movably disposed in the inner cavity of the intermediate body 5150. Among them, the outer valve body 5120 has a first fuel nozzle 5122 and a first valve seat 5123. The intermediate body 5150 has a second fuel nozzle 5152 and a second valve seat 5153. A first pressure chamber 5126 and a first control chamber 5129 are formed between the intermediate body 5150 and the outer valve body 5120. The first fuel nozzle 5122 communicates with the first pressure chamber 5126 through the first valve seat 123. A second pressure chamber 5156 and a second control chamber 5159 are formed between the needle valve 5180 and the intermediate body 5150. The second fuel nozzle 5152 communicates with the second pressure chamber 5156 through the second valve seat 5153. The first fuel inlet 5131 opens at the top of the secondary housing 5104, and the second fuel inlet 5161 opens at the side wall of the main housing 5102. The second fuel inlet 5161 is located between the first fuel inlet 5131 and the first fuel nozzle 5122. A first elastic member, such as a first helical spring 5193, is disposed in the first control chamber 5129, and a second elastic member, such as a second helical spring 5194, is disposed in the second control chamber 5159.

[0108] The fuel injector 5100 includes a pair of first input channels 5130 communicating with the first pressure chamber 5126 and a first return channel 5140 communicating with the first control chamber 5129. The first input channels 5130 are formed in the main housing 5102 and the secondary housing 5104 and are in fluid communication with the first fuel inlet 5131. The first input channels 5130 constitute the fluid communication between the first pressure chamber 5126 and the first fuel inlet 5131. The first return channel 5140 is formed in the main housing 5102 and constitutes the fluid communication between the first control chamber 5129 and the first solenoid valve 5191.

[0109] The fuel injector 5100 further includes a pair of second input channels 5160 communicating with the second pressure chamber 5156 and a second return channel 5170 communicating with the second control chamber 5159. The second input channels 160 are formed in the main housing 5102 and are in fluid communication with the second fuel inlet 5161. The second input channels 5160 constitute the fluid communication between the second pressure chamber 5156 and the second fuel inlet 5161. The second return channel 5170 is formed in the main housing 5102 and the secondary housing 5104 and constitutes the fluid communication between the second control chamber 5159 and the second solenoid valve 5192.

[0110] A feed ring groove 5155 and a reflux ring groove 5158 offset from the feed ring groove 5155 along the longitudinal axis 590 are formed between the outer valve body 5120 and the intermediate body 5150. The feed ring groove 5155 includes a first inner groove 5155a formed around the inner wall of the outer valve body 5120 and a first outer groove 5155b formed around the outer wall of the intermediate body 5150 and aligned with the first inner groove 5155a along the longitudinal axis 590. The reflux ring groove 5158 includes a second inner groove 5158a formed in and around the inner wall of the outer valve body 5120 and a second outer groove 5158b formed in and around the outer wall of the intermediate body 5150 and aligned with the first inner groove 5155a along the longitudinal axis 590. The second control cavity 5159 communicates between the feed ring groove 5155 and the reflux ring groove 5158.

[0111] The second input channel 5160 includes a pair of primary input segments 5162 formed in the outer valve body 5120 and a pair of secondary input segments 5164 formed in the intermediate body 5150. The inlet 5162a of each primary input segment 5162 opens to the top surface 5120a of the outer valve body 5120. The outlet 5162b of each primary input segment 5162 and the inlet 5164a of each secondary input segment 5164 communicate with the feed ring groove 5155 respectively. As Figure 10A and Figure 10B shown, the radial distance 51621a between the inlet 5162a of the primary input segment 5162 and the longitudinal axis 590 of the fuel injector 100 is greater than the radial distance 51621b between the outlet 5162b of the primary input segment 5162 and the longitudinal axis 590 of the fuel injector 5100, that is, the outlet 5162b of the primary input segment 5162 is closer to the longitudinal axis 590 relative to the inlet 5162a, so that the primary input segment 5162 is inclined relative to the longitudinal axis 90 and is arranged to narrow towards the direction of the second fuel nozzle 5152.

[0112] The outlet 5164b of each secondary input segment 5164 communicates with the second pressure cavity 5156. The feed ring groove 5155 and the second pressure cavity 5156 are arranged at different height positions along the longitudinal axis 590, so that the second pressure cavity 5156 is located between the feed ring groove 5155 and the second fuel nozzle 5152. The radial distance 51641a between the inlet 5164a of the secondary input segment 5164 and the longitudinal axis 590 of the fuel injector 5100 is greater than the radial distance 51641b between the outlet 5164b of the secondary input segment 5164 and the longitudinal axis 590 of the fuel injector 5100, and the outlet 5164b of the secondary input segment 5164 is located between the inlet 5164a of the secondary input segment 5164 and the second fuel nozzle 5152 along the longitudinal axis 590 direction. In other words, the outlets 5164b of the pair of secondary input segments 5164 are closer to the longitudinal axis 590 relative to the inlets 5164a, so that the secondary input segments 5164 are inclined relative to the longitudinal axis 590 and are arranged to narrow towards the direction of the second fuel nozzle 5152.

[0113] Reference Figures 3 to 6 , as an example, a pair of first input channels 5130 are arranged along a first radial direction 5111 of the outer valve body 5120. A pair of second input channels 5160 are arranged along a second radial direction 5112 of the outer valve body 5120. The second radial direction 5112 is angularly misaligned with respect to the first radial direction 5111 along a second circumferential direction 5112a of the outer valve body 5120 with the longitudinal axis 590 of the fuel injector 5100 as the axis. The second return channel 5170 is arranged along a third radial direction 5113. The third radial direction 5113 is angularly misaligned with respect to the first radial direction 5111 along a third circumferential direction 5113a of the outer valve body 5120 with the longitudinal axis 590 of the fuel injector 5100 as the axis. The third circumferential direction 5113a and the second circumferential direction 5112a are in opposite directions. A second input channel 5160 and a first control channel 5127 are also formed in the outer valve body 5120. The second input channel 5160 and the first control channel 5127 communicate with the first control cavity 5129. The first control channel 5127 is arranged along the third radial direction 5113. The first control channel 5127 has a pore diameter that can provide a pressure difference along the way between the second input channel 5160 and the first control cavity 5129, so as to form a damping through hole between the second input channel 5160 and the first control cavity 5129. According to the above arrangement, a pair of first input channels 5130, a pair of second input channels 5160 and the second return channel 5170 are all formed in the outer valve body 5120, and the structural space provided by the outer valve body 5120 is obtained and reasonably utilized, making the overall structure of the fuel injector 5100 compact, and constituting an external dimension that can adapt to the existing engine cylinder block, so that there is no need to substantially modify the existing engine and the fuel injector installation interface.

[0114] The second return channel 5170 includes a primary return section 5172 formed in the intermediate body 5150 and a secondary return section 5174 formed in the outer valve body 5120. The inlet of the primary return section 5172 communicates with the second control cavity 5159, and the outlet of the primary return section 5172 and the inlet of the secondary return section 5174 communicate with the return ring groove 5158 respectively. Among them, the secondary return section 5174 is arranged along the third radial direction 1135( Figure 6 ).

[0115] The intermediate body 5150 includes a second control channel 5157 that communicates with the second input channel 5160 and the second control cavity 5159. The second control channel 5157 is arranged along the third radial direction 5113. The second control channel 5157 has a pore diameter that can form a pressure difference along the way between the second input channel 5160 and the second control cavity 5159, so as to form a damping through hole between the second input channel 5160 and the second control cavity 5159.

[0116] The fuel injector 5100 further includes a return outlet 5176 opening to the side of the main housing 5102, and a return passage 5178 communicating between the return outlet 5176, the first solenoid valve 5191, and the second solenoid valve 5192. The return passage 5178 communicates with the corresponding first return passage 5140 and second return passage 5170 through the first solenoid valve 5191 and the second solenoid valve 5192.

[0117] In one embodiment, as Figure 7 shown, the inner cavity of the intermediate body 5150 has a guiding inner surface, such as a cylindrical inner surface. The needle valve 5180 includes a prismatic segment 5185 corresponding to a portion of the guiding inner surface of the intermediate body 5150, thereby forming a plurality of circumferentially distributed guiding ridges 5184 and connecting portions 5186 between adjacent guiding ridges. The guiding ridges 5184 abut against the guiding inner surface of the intermediate body 5150, and the enveloping surface of the guiding ridges 5184 forms a close translational fit with the cylindrical inner surface of the inner cavity of the intermediate body 5150, so that the intermediate body 5150 provides guiding support for the needle valve 5180. At the same time, a radial gap 5182 is formed between the connecting portion 5186 and the guiding inner surface. The radial gap 5182 constitutes a liquid passage. The radial gap 5182 constitutes a part of the second pressure chamber 5156. After the second solenoid valve 5192 is opened, the second fuel can pass through the radial gap 5182 during the flow in the second pressure chamber 5156 from the feed ring groove 5155 and be ejected from the second fuel nozzle 5152.

[0118] The intermediate body 5150 can translate between a first intermediate position 51501 and a second intermediate position 51502 relative to the outer valve body 5120. When in the first intermediate position 51501, as Figure 11 shown, the intermediate body 5150 abuts against and closely adjoins the first valve seat 5123 to block the fluid communication between the first pressure chamber 5126 and the first fuel nozzle 5122. When in the second intermediate position 51502, as Figure 12 shown, the intermediate body 5150 is spaced apart from the first valve seat 5123 to communicate the first pressure chamber 5126 with the first fuel nozzle 5122. Independently of the translation of the intermediate body 5150 relative to the outer valve body 5120, the needle valve 180 can translate between a first needle valve position 51801 and a second needle valve position 51802 relative to the intermediate body 5150. When in the first needle valve position 51801, as shown in FIG. 10, the needle valve 5180 abuts against and closely adjoins the second valve seat 5153 to block the fluid communication between the second pressure chamber 5156 and the second fuel nozzle 5152. When in the second needle valve position 51802, as Figure 12 shown, the needle valve 5180 is spaced apart from the second valve seat 5153 to communicate the second pressure chamber 5156 with the second fuel nozzle 5152.

[0119] When the fuel injector 5100 is in operation, a first fuel, such as liquid methanol, is supplied by a first fuel high-pressure pump through a first fuel inlet 5131 and enters a first input passage 5130 and a first pressure chamber 5126. A second fuel, such as liquid diesel, is supplied by a second fuel high-pressure pump through a second fuel inlet 5161 and enters a second input passage 5160, a first return passage 5140, a second return passage 170, a first control chamber 5129, a second control chamber 5159, a first control passage 5127, a second control passage 5157, and a second pressure chamber 5156.

[0120] A first solenoid valve 5191 is used to control the injection of the first fuel. When the first solenoid valve 5191 is opened, the second fuel in the first control chamber 5129 flows through the first return passage 5140 and the first solenoid valve 5191 to a return outlet 5176, thereby causing the liquid pressure in the first control chamber 5129 to be less than the liquid pressure in the first pressure chamber 5126. At the same time, under the damping action of the first control passage 5127, a liquid pressure difference is formed between the first control chamber 5129 and the first pressure chamber 5126. When the thrust applied to the intermediate body 5150 in the direction away from the first nozzle 5122 by the liquid pressure difference between the first control chamber 5129 and the first pressure chamber 5126 is greater than the elastic force of the first elastic member 5193, the intermediate body 5150 is driven by the first fuel in the first pressure chamber 5126 and translates from a first intermediate position 51501( Figure 11 ) to a second intermediate position 51502( Figure 12 ). The intermediate body 5150 forms a connection between the first pressure chamber 5126 and the first fuel nozzle 5122 at the second intermediate position 51502, enabling the first fuel to be ejected from the first fuel nozzle 5122 of the fuel injector 5100 to supply the first fuel to the engine on which the fuel injector 5100 is mounted. After the first solenoid valve 5191 is closed, the second fuel flows through the first control passage 5127 to the first control chamber 5129, causing the pressure in the first control chamber 5129 to increase. When the pressure difference between the first control chamber 5129 and the first pressure chamber 5126 is less than the elastic force of the first elastic member 5193, the intermediate body 5150 resets to the first intermediate position 51501( Figure 11 ), closing the connection between the first pressure chamber 5126 and the first fuel nozzle 5122, thereby stopping the ejection of the first fuel from the first fuel nozzle 5122.

[0121] Independently of the control of the first solenoid valve 5191, the second solenoid valve 5192 is used to control the injection of the second fuel. When the second solenoid valve 5192 opens, the second fuel in the second control chamber 5159 flows through the second return passage 5170 and the second solenoid valve 5192 to the return outlet 5176. This causes the liquid pressure in the second control chamber 5159 to decrease and become less than the liquid pressure in the second pressure chamber 5156. At the same time, under the damping action of the second control passage 5157, a liquid pressure difference is formed between the second control chamber 5159 and the second pressure chamber 5156. When the thrust exerted on the needle valve 5180 by the liquid pressure difference between the second control chamber 5159 and the second pressure chamber 5156 in the direction away from the second nozzle 5152 is greater than the elastic force of the second elastic member 5194, the needle valve 5180 is driven by the second fuel in the second pressure chamber 5156 and translates from the first needle valve position 51801( Figure 11 ) to the second needle valve position 51802( Figure 13 ). The needle valve 5180 forms a communication between the second pressure chamber 5156 and the second fuel nozzle 5152 at the second needle valve position 51802, enabling the second fuel to be ejected from the second fuel nozzle 5152 of the fuel injector 5100 to supply the second fuel to the engine on which the fuel injector 5100 is mounted. After the second solenoid valve 5192 closes, the second fuel flows through the second control passage 5157 to the second control chamber 5159, causing the pressure in the second control chamber 5159 to increase. When the pressure difference between the second control chamber 5159 and the second pressure chamber 5156 is less than the elastic force of the second elastic member 5194, the needle valve 5180 resets to the first needle valve position 51801, closing the communication between the second pressure chamber 5156 and the second fuel nozzle 5152, thereby stopping the ejection of the second fuel from the second fuel nozzle 5152. As described above, by independently and / or coordinately opening and closing the first solenoid valve 5191 and the second solenoid valve 5192, the injection or stop of injection of the first fuel and the second fuel can be controlled, thereby supplying the first fuel and the second fuel to the engine.

[0122] As used herein, unless otherwise clearly specified, the singular "a" and "an" may be construed to include the plural "one or more".

[0123] This novelty is for purposes of illustration and description and is not intended to be exhaustive or restrictive. Many modifications and variations will be apparent to those of ordinary skill in the art. The example embodiments selected and described herein are for the purpose of explaining the principles and practical applications, enabling those of ordinary skill in the art to understand the various modifications suitable for the various embodiments of this novelty to achieve the desired specific technical effects.

[0124] Accordingly, although illustrative example embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the description is not restrictive, and various other changes and modifications may be made by those skilled in the art without departing from the scope or inventive concept and implementation of the present novelty.

Claims

1. A combined dual - fuel injector, characterized in that, the combined dual - fuel injector comprises: a main housing; an outer valve body connected to the main housing, the outer valve body having a first fuel injection port and a first valve seat; an intermediate body movably disposed in the inner cavity of the outer valve body, the intermediate body including an upper segment and a lower segment, the lower segment having a second fuel injection port and a second valve seat, a first pressure chamber being formed between the lower segment and the outer valve body, a first control chamber being formed between the upper segment and the outer valve body, and the first fuel injection port communicating with the first pressure chamber through the first valve seat; a needle valve movably disposed in the inner cavity of the intermediate body, a second pressure chamber and a second control chamber being formed between the needle valve and the intermediate body, and the second fuel injection port communicating with the second pressure chamber through the second valve seat; wherein the intermediate body can move relative to the outer valve body between a first intermediate position and a second intermediate position; when in the first intermediate position, the intermediate body abuts against the first valve seat to block the fluid connection between the first pressure chamber and the first fuel injection port; when in the second intermediate position, the intermediate body is spaced apart from the first valve seat to connect the first pressure chamber and the first fuel injection port; the needle valve can move 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 injection port; 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 injection port.

2. The dual - fuel injector according to claim 1, characterized in that, the upper segment and the lower segment are assembled to form the intermediate body, and a fluid seal is formed between the upper segment and the lower segment.

3. The dual - fuel injector according to claim 1, characterized in that, the upper segment includes an axially - extending sleeve portion, and the lower segment includes the axially - extending lower protruding portion, and the sleeve portion is coupled to the lower protruding portion.

4. The dual - fuel injector according to claim 3, characterized in that, the inner diameter of the sleeve portion is smaller than the outer diameter of the lower protruding portion.

5. The dual - fuel injector according to claim 3, characterized in that, a first sealing interface and a second sealing interface are formed between the sleeve portion and the lower protruding portion, wherein the first sealing interface is formed between the outer side wall of the lower protruding portion and the inner side wall of the sleeve portion, and the second sealing interface is formed between the shoulder of the lower segment and the end wall of the sleeve portion.

6. The dual - fuel injector according to claim 1, characterized in that, the upper segment and the lower segment can be assembled in a plurality of relative positions in the circumferential direction.

7. The dual - fuel injector according to claim 1, characterized in that, the upper segment forms an upper inner bore, the lower segment forms a lower inner bore, and the upper inner bore and the lower inner bore constitute the inner bore of the intermediate body.

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