Dual fuel engine system, intake manifold, and method for manufacturing a dual fuel engine system

Abstract

To provide a dual-fuel engine system, an intake manifold, and a method for manufacturing a dual-fuel engine system. [Solution] A dual-fuel engine system and / or modified system comprises a cylinder head, an intake manifold, a first fuel injector, and a second fuel injector. The cylinder head defines an intake port. The intake manifold is coupled to the cylinder head. The first fuel injector extends into the cylinder head and is configured to supply a fixed amount of the first fuel. The second fuel injector extends into the cylinder head through the intake manifold. The second fuel injector is configured to supply a fixed amount of the second fuel. The second fuel injector is oriented to spray the second fuel into the intake port.

Description

Technical Field

[0001] The present disclosure generally relates to the field of dual fuel engine systems and fuel systems for dual fuel engine systems.

Background Art

[0002] Dual fuel engine systems are designed to operate using a combination of fuels that can be either gaseous or liquid fuels. Existing dual fuel engine systems are often designed to use a primary fuel that is typically diesel or gasoline, and a secondary fuel that is methanol, ethanol (e.g., alcohol-based fuels), or other types of liquid or gaseous fuels. These engine systems can operate using only the primary fuel or, in dual fuel mode, using both the primary and secondary fuels in a compression ignition engine. In some dual fuel engine systems, a majority of the fuel energy can be supplied by the secondary fuel. By using the secondary fuel, it is possible to reduce the carbon intensity of the fuel consumed and the amount of carbon dioxide emissions generated by the engine system during operation. Additionally, by using the secondary fuel, it is possible to reduce the operating cost compared to operating using only the primary fuel.

Summary of the Invention

Means for Solving the Problems

[0003] One aspect of the present disclosure relates to a dual-fuel engine system comprising a cylinder head, an intake manifold, a first fuel injector, and a second fuel injector. The cylinder head defines an intake port. The intake manifold is coupled to the cylinder head. The first fuel injector extends into the cylinder head and is configured to supply a fixed amount of the first fuel. The second fuel injector extends into the cylinder head through the intake manifold. The second fuel injector is configured to supply a fixed amount of the second fuel. The second fuel injector is oriented to spray the second fuel into the intake port.

[0004] Another aspect of the present disclosure relates to an intake manifold comprising a manifold body and an injector mount. The manifold body defines an airflow plenum through which an airflow plenum passes. The injector mount extends at least partially through the airflow plenum. The injector mount defines a bore that extends through both ends of the manifold body. The bore is sized to receive a fuel injector inside. The injector mount comprises a tube that fluidly separates the bore from the airflow plenum along the entire axial length of the bore.

[0005] A further aspect of the present disclosure relates to a method for manufacturing a dual-fuel engine system. The method includes the step of coupling an intake manifold to a cylinder head of a dual-fuel engine system, the dual-fuel engine system comprising a first fuel injector extending into the cylinder head. The first fuel injector is configured to supply a quantitative amount of a first fuel. Furthermore, the method includes the step of inserting a second fuel injector into the cylinder head through the intake manifold such that the second fuel injector is oriented to spray a second fuel into an intake port defined by the cylinder head.

[0006] This summary is for illustrative purposes only and should not be considered limiting.

[0007] This disclosure will be better understood from the following detailed description in combination with the attached drawings. In these drawings, similar reference numerals indicate similar elements. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of a dual-fuel engine system, showing the intake manifold of a dual-fuel engine system according to one embodiment. [Figure 2] Figure 1 is a front cross-sectional view of the dual-fuel engine system, along the secondary fuel injector of the dual-fuel engine system. [Figure 3] This is an upper cross-sectional view of the dual-fuel engine system shown in Figure 1, along the secondary fuel injector. [Figure 4] Figure 1 shows another perspective view of the dual-fuel engine system and intake manifold. [Figure 5] This is a perspective view of another intake manifold for use with a dual-fuel engine system according to one embodiment. [Figure 6] This is an upper cross-sectional view of the dual-fuel engine system shown in Figure 1, along the secondary fuel injector. [Figure 7] This is a repeat of Figure 6, showing the sealing surface between (i) the secondary fuel injector and (ii) the intake manifold and cylinder head of the dual fuel engine system. [Figure 8] Figure 1 is a perspective view of the secondary fuel injector. [Figure 9] Figure 1 is a perspective view of a rotating support element for a dual-fuel engine system. [Figure 10] This is a flowchart of a method for manufacturing a dual-fuel engine system according to one embodiment, and / or a method for modifying a compression-ignition engine system for the use of multiple fuels. [Modes for carrying out the invention]

[0009] The following detailed description will refer to the accompanying drawings, which constitute part of this specification. In these drawings, unless otherwise specified in the context, similar reference numerals generally indicate similar components. The exemplary embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be utilized and other modifications may be made without departing from the spirit or scope of the subject matter shown herein. The aspects of this disclosure outlined herein and shown in the drawings can be arranged, substituted, combined, and designed in a wide variety of configurations, all of which are expected within the scope of this specification and constitute part of this disclosure.

[0010] Embodiments of the present disclosure relate to a system and method for modifying a single-fuel compression-ignition engine system or a spark-ignition engine system (e.g., an existing engine system configured to use a single fuel, such as diesel fuel) for use with multiple fuels or for fuel injection using a port injection configuration, while reducing the number of new components and parts in use that need to be modified or replaced in the compression-ignition engine system. The system comprises an intake manifold designed to internally receive and support a second fuel injector for secondary fuel. The intake manifold is designed to support the second fuel injector in a fixed position within the cylinder head, thereby directing the second fuel toward the intake port of the cylinder head. Beneficially, such an arrangement allows access to the second fuel injector from outside the engine system, thereby enabling maintenance / servicing of the second fuel injector without further extensive removal of other engine system hardware (e.g., turbocharger, intake manifold, exhaust manifold, and / or other engine equipment / accessories). Furthermore, this arrangement makes it possible to incorporate a second fuel injector near the cylinder without requiring significant redesign of the cylinder head.

[0011] The following description concerns the configuration of a compression ignition engine system, but it should be understood that the same or similar designs as those of modification system 200 may also be used for other types of engine systems. These other types include those aimed at 1) providing a port injection (e.g., port fuel injection) configuration to a spark ignition engine system, 2) providing a port injection configuration to an engine system using only one fuel, and 3) achieving dual fuel injection in an engine system using two fuels, as well as 4) an engine system that uses only port injectors to deliver fuel to the engine, and 5) an engine system having both port injectors (e.g., port fuel injectors) and a second (potentially primary) fuel system. This second fuel system can be a direct fuel injection system, an upstream mixed fuel injection system (e.g., a fuel mixer upstream of the compressor), or a fuel system located between the compressor inlet and the port fuel injector.

[0012] In some embodiments, the second fuel injector is positioned to spray secondary fuel toward the rear of the intake valve head of the compression ignition engine system. In at least one embodiment, the second fuel injector is an offset fuel injector having an asymmetrical spray plume that is emitted from only one side of the fuel injector (e.g., the peripheral portion). In such embodiments, the second fuel injector is rotatably aligned with respect to the intake manifold and cylinder head to deliver the second fuel only toward the rear side of the intake valve head. Beneficially, such an arrangement can reduce the risk of fuel buildup in the cylinder head. Furthermore, such an arrangement can reduce fuel collisions (i.e., wall wetting) with the inner surface of the cylinder head and the intake line of the cylinder head, which can adversely affect transient performance and exhaust emissions associated with fuel injection outside the cylinder.

[0013] Referring to Figures 1 to 3, a dual-fuel engine system 100 according to one embodiment is illustrated. The dual-fuel engine system 100 comprises a cylinder head 102 defining an intake port 104, an intake manifold 202 coupled to the cylinder head 102, a first fuel injector 106 extending into the cylinder head 102 and configured to supply a fixed amount of a first fuel 108, and a second fuel injector 204 extending into the cylinder head 102 through the intake manifold 202. The second fuel injector 204 is configured to supply a fixed amount of a second fuel 110 that is different from the first fuel 108. In another embodiment, the second fuel injector 204 is configured to supply a fixed amount of a second fuel 110 that is identical to the first fuel. The second fuel injector 204 is oriented to spray the second fuel 110 into the intake port 104.

[0014] In some embodiments, the intake manifold 202 and the second fuel injector 204 together define part of a modification system 200 (e.g., an upfit system, a second fuel injection system, etc.). This modification system 200 is configured to modify an existing single-fuel compression-ignition engine system for the use of multiple fuels (e.g., configured to form a dual-fuel engine system 100 by modifying an existing single-fuel compression-ignition engine system). In some embodiments, the single-fuel compression-ignition engine system is a direct-injection diesel engine having at least one first fuel injector 106 configured to spray fuel directly into a cylinder 112. In some embodiments, this modification system 200 further comprises a fuel rail assembly 206 configured to supply a second fuel 110 to a second fuel injector 204, as will be described further below.

[0015] In some embodiments, components used for the modification system 200 (e.g., tubes, pipes, seals, etc.) are formed from materials that have chemical compatibility for use with a second fuel. These materials can also be compatible for use with other fluids and gases used in or produced by the internal combustion engine system (e.g., glycols, oils, diesel, etc.) and can be formed from materials that can withstand the operating temperature range of the internal combustion engine system and the applications in which the internal combustion engine system is used.

[0016] Furthermore, the modification system 200 may also include a dual fuel control module, which may be an electronically controlled module or a direct fuel control module. The dual fuel control module may be configured to control the fuel supply and operation of the second fuel injector 204 by communicating with an existing single-fuel compression ignition engine control module.

[0017] Referring to Figures 2 and 3, the dual-fuel engine system 100 further comprises an engine block 105 (e.g., a cylinder block) coupled to the cylinder head 102. The engine block 105 defines the cylinder 112.

[0018] The first fuel injector 106 extends into the cylinder 112, penetrating the cylinder head 102. In the embodiments shown in Figures 2 and 3, the first fuel injector 106 is a diesel fuel injector configured to directly inject a first fuel 108 (e.g., primary fuel) into the cylinder 112. The primary fuel can be diesel fuel or other types of liquid or gaseous fuel. The first fuel injector 106 may comprise a nozzle and a solenoid valve for controlling the flow of the first fuel 108 through the nozzle.

[0019] The cylinder head 102 is configured to send an air flow from the intake manifold 202 to the cylinder 112 of the dual fuel engine system 100. Further, the cylinder head 102 is configured to send an exhaust gas flow from the cylinder 112. In the embodiments of FIGS. 2-3, the cylinder head 102 defines at least one intake port 104, an intake opening 114, and an injector bore 116.

[0020] At least one intake port 104 is configured to fluidly couple the intake manifold 202 (e.g., a fluid passage within the intake manifold 202) to the cylinder 112. The intake port 104 includes an intake channel 105 (e.g., an intake passage, etc.) configured to send air (e.g., charge air, etc.) through the cylinder head 102. Further, the intake port 104 includes an intake opening 114 disposed at an end of the intake channel 105 remote from the intake manifold 202. In some embodiments, the intake opening 114 defines the entire end of the intake port 104. In the embodiments of FIGS. 2-3, the cylinder head 102 defines a plurality of intake ports 104, and each of these intake ports 104 is configured to supply air to a respective one of the plurality of cylinders 112.

[0021] The intake opening 114 is configured to fluidly couple at least one intake channel 105 to the cylinder 112. In the embodiments of FIGS. 2-3, the intake opening 114 is disposed at an end (e.g., a distal end, an outlet end, etc.) of the intake channel 105 that is furthest from the intake manifold and / or at a location where the cylinder head 102 is coupled to the intake manifold 202. The intake opening 114 is disposed at an outlet end of the intake channel 105 that is furthest from the intake manifold 202 along the direction of the air flow through the cylinder head 102. The intake opening 114 is sized to receive a portion (e.g., a valve stem 122 of the intake valve 120) of the intake valve 120. The valve head 124 of the intake valve 120 engages the cylinder head 102 at the intake opening 114.

[0022] The injector bore 116 is sized to receive the distal end of the second fuel injector 204 (e.g., the tip portion defining at least one nozzle 242) and to guide the second fuel injector 204 toward a portion of the intake port 104 near the intake opening 114. In the embodiments shown in Figures 2 and 3, the injector bore 116 is a cylindrical passage extending from the outer surface 118 of the cylinder head (e.g., the intake manifold joint surface) into the intake port 104. In some embodiments, the injector bore 116 is formed by machining (e.g., drilling) the passage within an existing cylinder head 102. In other embodiments, the injector bore 116 is formed integrally with the cylinder head 102 during the casting process.

[0023] In some embodiments, the injector bore 116 (e.g., the central axis of the injector bore 116) extends substantially parallel to the airflow direction 119 through the intake port 104. In other embodiments, the orientation of the injector bore 116 with respect to the intake port 104 can be different.

[0024] In at least one embodiment, the cylinder head 102 is part of a cylinder head assembly 117 further comprising at least one intake valve 120 coupled to the cylinder head 102. The intake valve 120 is at least partially disposed within the cylinder head 102. The intake valve 120 covers an intake opening 114 and is configured to selectively introduce air from the intake port 104 into the cylinder 112.

[0025] The intake valve 120 comprises a valve stem 122 and a valve head 124 coupled to the end of the valve stem 122. The valve head 124 is configured to engage with the cylinder head 102 at the intake opening 114. The valve head 124 defines a rear surface 126 facing the intake port 104. Furthermore, the valve head 124 defines a front surface 128 located opposite the rear surface 126 facing the cylinder 112.

[0026] In the embodiments shown in Figures 2 and 3, the injector bore 116 (e.g., the central axis of the injector bore 116) is oriented substantially perpendicular to the valve stem 122. In other embodiments, different relative orientations of the injector bore 116 and the valve stem 122 are possible.

[0027] The intake manifold 202 is configured to supply air to the cylinder head 102 (for example, to the intake port 104). Furthermore, the intake manifold 202 is configured to connect a second fuel injector 204 to the dual fuel engine system 100.

[0028] The intake manifold 202 comprises a manifold body 208 that defines an airflow plenum 211 passing through its interior. Furthermore, the intake manifold 202 comprises an injector mount 210 that extends at least partially through the airflow plenum 211. The injector mount 210 defines a bore 212 that extends through both ends of the manifold body 208. The bore 212 is sized to receive a fuel injector (e.g., a second fuel injector 204) inside. The injector mount 210 comprises a tube 214 that fluidly separates the bore 212 from the airflow plenum 211 along the entire axial length of the bore 212.

[0029] The airflow plenum 211 is configured to deliver air from the outside air intake and / or intercooler of the dual-fuel engine system 100 to the cylinder head 102. The airflow plenum 211 is an internal passage or combination of internal passages that extends through the manifold body 208. In some embodiments, the airflow plenum 211 comprises multiple airflow passages for uniformly distributing air between the intake ports 104 of the cylinder head 102.

[0030] The intake manifold 202 (e.g., manifold body 208) includes an injector mount 210 that extends through its interior. The injector mount 210 is configured to support a second fuel injector 204 at a fixed position on the manifold body 208. In the embodiments shown in Figures 2 and 3, the injector mount 210 includes a tube 214 defining a bore 212. The bore 212 is a cylindrical bore having a substantially circular cross-section (e.g., a circular cross-section perpendicular to its central axis).

[0031] The injector mount 210 (e.g., tube 214) separates the airflow plenum 211 of the intake manifold 202 from the second fuel injector 204 (e.g., from the bore 212). Tube 214 extends along the entire length of the intake manifold 202, preventing air from passing through the bore 212 and bypassing the airflow plenum 211 and / or the cylinder head 102.

[0032] Referring to Figure 3, the tube 214 of the injector mount 210 includes a step 216 (e.g., a shelf-like section) extending radially inward from the inner surface of the bore 212, located near the end 213 of the bore 212 (e.g., the distal end) (e.g., near the manifold joint surface of the intake manifold 202 configured to engage with the cylinder head 102).

[0033] In the embodiments shown in Figures 2 and 3, step 216 creates a stepwise change in the diameter of the bore 212, dividing it into a first portion 218 (e.g., a first region) extending from a first outer surface of the intake manifold 202 (e.g., the manifold joint surface) and a second portion 220 (e.g., a second region) extending from the first portion 218 to a second outer surface of the intake manifold 202 located on the opposite side of the first outer surface. The first portion 218 of the bore 212 extends through the first end 222 of the manifold body 208. The second portion 220 of the bore 212 extends through the second end 224 located on the opposite side of the first end 222 of the manifold body 208.

[0034] Step 216 separates the first portion 218 from the second portion 220. The first portion 218 has a smaller inner diameter than the second portion 220. Step 216 defines at least one sealing surface of the second fuel injector 204.

[0035] In at least one embodiment, the intake manifold 202 (e.g., injector mount 210, tube 214, manifold body 208, etc.) defines a plurality of sealing surfaces for the second fuel injector 204, which are configured to engage with the sealing member of the second fuel injector 204 to prevent loss of the second fuel 110 and / or leakage of charge air from the cylinder head 102. In the embodiment of Figure 3, step 216 defines a first axially facing sealing surface 226 of the injector mount 210. The first axially facing sealing surface 226 is a surface of step 216 oriented substantially perpendicular to the central axis 228 of the tube 214.

[0036] The injector mount 210 (e.g., tube 214) further defines a second axially facing seal surface 230 disposed along the periphery of the bore 212. This second axially facing seal surface 230 is axially spaced apart from the first axially facing seal surface 226. In the embodiment shown in Figure 3, the second axially facing seal surface 230 is defined by the surface of the tube 214 over the entire axial end of the tube 214.

[0037] The second axially facing seal surface 230 is oriented substantially parallel to the first axially facing seal surface 226. Beneficially, by incorporating the axially facing seal surface into the injector mount 210, it becomes possible to allow a wider range of dimensional tolerances for the injector bore 116, as will be further described below.

[0038] Referring to Figure 4, the injector mount 210 may be formed integrally with the intake manifold 202 as a single structural body from a single piece of material. In such an embodiment, the injector mount 210 may be formed at least partially during the casting process of the intake manifold 202. Furthermore, the bore 212 may be formed during the casting process and / or at least partially formed by machining (e.g., drilling) after the completion of the casting operation.

[0039] The manifold body 208 further defines a rail assembly mount 232 for supporting a fuel rail assembly 206 (e.g., an accumulator) (see also Figure 2) on the manifold body 208. In some embodiments, the fuel rail assembly 206 is a common fuel rail configured to supply a second fuel 110 at high pressure to a plurality of second fuel injectors 204 (see Figure 3).

[0040] In some embodiments, the fuel rail assembly 206 comprises a double-walled fuel line and fuel rail. In some embodiments, these double-walled fuel lines and / or fuel rails are equipped with a nitrogen (or other inert gas) purging system to facilitate the removal of fuel from the fuel lines and / or fuel rails. In some embodiments, another part of the fuel rail assembly 206 and / or modification system 200 is equipped with a leak detection system configured to monitor conditions within the double-walled fuel line and / or fuel rail and to detect leaks into the internal volume of the double-walled section.

[0041] In some embodiments, the dual-fuel engine system 100 (e.g., fuel rail assembly 206, intake manifold 202, etc.) includes a purge and drain system for the second fuel. The purge and drain system is configured to reduce the volume of the second fuel trapped within the dual-fuel engine system 100 (e.g., within the fuel rail assembly 206, intake manifold 202, etc.). In some embodiments, the purge and drain system is a gravity-type system that drains the second fuel from the engine system 100 under gravity (e.g., after the engine system 100 has stopped). In the embodiment shown in Figure 4, the rail assembly mount 232 includes a plurality of mounting elements 236 that extend parallel to the tube 214 of the injector mount 210. The mounting elements 236 define a mounting opening for the fuel rail assembly 206 to connect the fuel rail assembly 206 to the intake manifold 202. In the embodiment shown in Figure 4, the rail assembly mount 232 is integrally formed with the intake manifold 202 as a single structural body from a single piece of material (for example, by a casting process).

[0042] Figure 5 shows another embodiment of an intake manifold 302 for a dual-fuel engine system. The intake manifold 302 comprises a plurality of injector mounts 310 configured to connect a plurality of second fuel injectors to the intake manifold 302. Each injector mount 310 comprises a tube 314 connected to the lower wall of the intake manifold 302. These tubes 314 extend across the intake manifold 302. The position and arrangement of the tubes 314 can differ in various embodiments.

[0043] Referring again to Figures 2 and 3, the second fuel injector 204 (e.g., alternative fuel injector, secondary fuel injector, liquid fuel injector, etc.) is configured to supply the second fuel 110 to the cylinder head 102. The second fuel injector 204 is one of a plurality of second fuel injectors, each configured to supply the second fuel 110 to each cylinder of the cylinder head. The second fuel injector 204 comprises an injector body 238 and a tip portion 240 having a nozzle 242. The injector body 238 includes an electronically controlled solenoid valve 244 configured to control the operation of the second fuel injector 204 and the delivery of the second fuel 110 to the cylinder head 102. In some embodiments, this solenoid valve 244 is a pulse-width modulation (PWM) valve that uses pulse-width modulation (PWM) to adjust the flow of the second fuel 110 to the cylinder head (e.g., adjust the duty cycle and / or spray duration, etc.).

[0044] In some embodiments, the second fuel 110 is a liquid fuel sprayed into the cylinder head 102 from a second fuel injector 204. The second fuel 110 can be an alcohol-based liquid fuel containing at least one of ethanol or methanol. In other embodiments, the second fuel 110 can be diesel gas fuel or natural gas fuel, e-fuel fuel, or liquid biofuel. In further embodiments, the second fuel 110 can be any one of the high-cetane fuels such as diesel fuel, gas-to-liquid (GTL) diesel fuel, heavy fuel oil (HFO), low-sulfur fuel oil (LFSO), hydrotreated vegetable oil (HVO), marine diesel fuel (MGO), renewable diesel fuel, biodiesel fuel, paraffinic diesel fuel, dimethyl ether (DME), F-76 fuel, F-34 fuel, jet fuel A, JP-4 fuel, JP-8 fuel, or oxymethylene ether (OME), or a low-cetane fuel (e.g., high-octane fuel, high-methane fuel). This low-cetane fuel can be natural gas, hydrogen, ethane, propane, butane, synthesis gas, ammonia, methanol, ethanol, or gasoline. The fuel can optionally be a mixture of fuels. It should be understood that the above are merely examples of fuels and do not exclude other types of fuels.

[0045] Referring to Figures 2 and 3, the second fuel injector 204 is an offset fuel injector configured to quantitatively supply the second fuel 110 to only one side of the second fuel injector 204. In this specification, an offset fuel injector is a fuel injector configured to produce an asymmetric spray pattern when viewed perpendicular to the central axis 246 of the second fuel injector 204. The offset fuel injector is configured to spray fuel from a first peripheral portion of the fuel injector (e.g., a first peripheral portion of the nozzle 242) while blocking the fuel flow from a second peripheral portion of the fuel injector. In such a configuration, the fuel spray is reduced to a single circumferential region relative to the fuel injector.

[0046] In the embodiments shown in Figures 2 and 3, the second fuel injector 204 is configured to spray the second fuel 110 from one side of its tip portion 240. The second fuel injector 204 is positioned relative to the intake manifold 202 and the cylinder head 102 to spray the second fuel 110 toward the intake opening 114 of the cylinder head 102. In some embodiments, the second fuel injector 204 is oriented to spray the second fuel 110 along the direction of the airflow through the cylinder head 102 during an intake event (for example, while air is being drawn from the cylinder head 102 into the cylinder). In some embodiments, the second fuel injector 204 and / or nozzle 242 are configured to spray the second fuel 110 toward the rear surface 126 of the valve head 124 such that the spray area does not extend radially beyond the rear surface 126 and / or the intake opening 114. This configuration reduces the risk of fuel accumulation within the intake manifold 202 and mitigates wall wetting that occurs when some fuel is trapped or retained along the cylinder head walls. This configuration can improve transient performance (for example, by shortening the time interval required for the second fuel 110 to reach the cylinder after the operation of the second fuel injector 204) and can further improve the accuracy of fuel delivery to the cylinder by reducing the amount and risk of fuel adhering to or otherwise retaining in the cylinder head after the operation of the second fuel injector 204.

[0047] In the embodiment shown in Figure 2, the central axis 246 of the second fuel injector 204 is oriented substantially vertically (e.g., perpendicularly) to the valve stem 122 of the intake valve 120. The nozzle 242 of the second fuel injector 204 is positioned to deliver the second fuel 110 toward the intake opening 114 at an angle 248 with respect to the central axis 246. In the embodiment shown in Figure 2, this angle 248 is approximately 45° with respect to the central axis 246. In other embodiments, the angle 248 can be a different angle (e.g., approximately 30°, approximately 60°, etc.) depending on the orientation of the second fuel injector 204 and nozzle 242 toward the intake opening 114.

[0048] Referring to Figures 6 and 7, the second fuel injector 204 is configured to engage in a sealing manner with both the cylinder head 102 and the intake manifold 202. The tip portion 240 of the second fuel injector 204 extends through the first portion 218 of the bore 212 of the intake manifold 202 into the injector bore 116 of the cylinder head 102. The injector body 238 is at least partially disposed within the second portion 220 of the bore 212.

[0049] Referring to Figure 7, the intake manifold 202 (e.g., bore 212) and the cylinder head 102 (e.g., injector bore 116) are sized such that the sum of the first radial gap 251 and the first annular space between the second fuel injector 204 and the intake manifold 202 is greater than the sum of the second radial gap 253 and the second annular space between the second fuel injector 204 and the cylinder head 102. This configuration allows the second fuel injector 204 to float radially within the bore 212 without significantly affecting the orientation of the tip portion 240 and nozzle 242 of the second fuel injector 204 within the cylinder head 102, thereby allowing for a wider range of dimensional tolerance variations between the cylinder head 102 and the intake manifold 202.

[0050] Referring to Figure 7, the second fuel injector 204 further comprises a first seal member 250, a second seal member 252, and a third seal member 254. The first seal member 250 is disposed axially between the second fuel injector 204 (e.g., the injector body 238) and the intake manifold 202. The first seal member 250 is positioned axially between the outer flange of the injector body 238 and the second axially facing seal surface 230 of the injector mount 210 (e.g., the tube 214). The first seal member 250 is an axial seal member configured to seally engage with the second axially facing seal surface 230 along the axial direction with respect to the central axis 246 of the second fuel injector 204.

[0051] The second sealing member 252 is positioned axially between the second fuel injector 204 and the intake manifold 202. The second sealing member 252 is positioned axially between (i) the end of the injector body 238 closest to the tip portion of the second fuel injector 204 (e.g., nozzle end, discharge end, etc.) and (ii) the first axially facing sealing surface 226 (e.g., step 216) of the injector mount 210 (e.g., tube 214). The second sealing member 252 is an axial sealing member configured to seally engage with the first axially facing sealing surface 226 along the axial direction of the second fuel injector 204 with respect to the central axis 246.

[0052] In the embodiment shown in Figure 7, the second cord diameter 256 of the second seal member 252 is larger than the first cord diameter 258 of the first seal member 250. In this specification, cord diameter refers to the outer diameter of the seal member material (e.g., the cross-sectional diameter of the seal member itself). Such a configuration allows for greater versatility regarding the axial position of the second fuel injector 204 and / or the angle of the second fuel injector 204 relative to the intake manifold 202. Furthermore, such a configuration allows for a wider range of dimensional variation in the modification system 200 (for example, this ensures sufficient deformation of the seal member even at the limits of the dimensional tolerance between the second fuel injector 204, the cylinder head 102, and the intake manifold 202, thereby maintaining accurate targeting of the fuel spray plume without excessively restricting the second fuel injector 204).

[0053] The first sealing member 250 and the second sealing member 252 provide a seal between the injector body 238 and the intake manifold 202, thereby preventing debris from entering the gap (e.g., an empty space) between the injector body 238 and the intake manifold 202.

[0054] The third sealing member 254 is positioned radially between the second fuel injector 204 and the cylinder head 102 when the second fuel injector 204 is fully inserted into the intake manifold 202. The third sealing member 254 is a radial sealing member configured to engage securely with the inner side wall of the injector bore 116 along the radial direction with respect to the central axis 246 of the second fuel injector 204. The third sealing member 254 is configured to prevent leakage of charge air and the second fuel 110 into the area between the cylinder head 102 and the intake manifold 202.

[0055] In the embodiments shown in Figures 6 and 7, the first sealing member 250, the second sealing member 252, and the third sealing member 254 are O-ring seals disposed in corresponding grooves and / or slots formed in the second fuel injector 204 (e.g., the injector body 238, the tip portion 240, etc.). In other embodiments, the first sealing member 250, the second sealing member 252, and the third sealing member 254 may be gaskets or sealant materials filled in the corresponding grooves / slots in the second fuel injector 204.

[0056] Referring again to Figure 1, the dual-fuel engine system 100 (e.g., modification system 200) further comprises a rotational support element 260 configured to fix a second fuel injector 204 in a single rotational position relative to the cylinder head 102. In the embodiment of Figure 1, the rotational support element 260 is a fuel injector clamp 262 that engages with the second fuel injector 204 located outside the intake manifold 202. The fuel injector clamp 262 is coupled to the manifold body 208 (e.g., by bolts or another type of mechanical fastener). In other embodiments, the rotational support element 260 may be located at a different location along the modification system 200 (e.g., another area of ​​the intake manifold 202). The second fuel injector 204 is constrained to a single rotational position relative to the intake manifold 202 and the cylinder head 102.

[0057] Referring to Figure 8, the second fuel injector 204 is provided with a fuel injector mounting flange 264 at the proximal end of the second fuel injector 204 (e.g., the injector body 238). This fuel injector mounting flange 264 is bonded to the injector body 238 (e.g., a sealing flange located at the proximal end of the injector body 238) by bolts or other types of mechanical fasteners. In other embodiments, the fuel injector mounting flange 264 can be welded to the injector body 238 or formed integrally with the injector body 238 from a single piece of material.

[0058] In the embodiment shown in Figure 8, the fuel injector mounting flange 264 is an elongated body having only one axis of symmetry passing through the central axis 246 of the second fuel injector 204. In the embodiment shown in Figure 8, this elongated body defines a first pair of parallel side surfaces 266 that are radially spaced apart from each other. In other embodiments, the shape of the fuel injector mounting flange 264 can be different. For example, the fuel injector mounting flange 264 can be shaped as an offset circle when viewed perpendicular to the central axis 246, as an offset ellipse, or as another shape that has no axis of symmetry or that can otherwise constrain the rotational position of the second fuel injector 204.

[0059] Referring to Figure 9, the rotational support element 260 comprises a support base 268 and a pair of extensions 270 (e.g., forks, prongs, blades, etc.) configured to receive a fuel injector mounting flange 264. The support base 268 defines at least one opening 269 configured to facilitate the coupling of the rotational support element 260 to the intake manifold 202 (see Figure 1). The pair of extensions 270 defines a second pair of parallel side surfaces 272 configured to fix the rotational position of the second fuel injector 204 within the intake manifold 202 by engaging with a first pair of parallel side surfaces 266.

[0060] The orientation of these side surfaces can differ in various embodiments (e.g., arranged at different angles). The design of the rotational support element 260 (e.g., having forks, prongs, blades, etc.) provides a visual indicator that facilitates the assembly and rotational alignment of the second fuel injector 204.

[0061] In some embodiments, the lower surface of at least a portion of the rotating support element 260 (e.g., a fork) is configured to engage with the upper surface of the fuel injector mounting flange 264, thereby holding the fuel injector mounting flange 264 against the machined surface of the intake manifold 202.

[0062] Referring to Figure 10, a method 400 is shown according to one embodiment for fabricating an engine system (e.g., a dual-fuel engine system) and / or modifying a single-fuel engine system (e.g., a compression-ignition engine system) for multi-fuel use. This method 400 may be used to fabricate the dual-fuel engine system 100 and / or modified system 200 shown in Figures 1 to 9. In other embodiments, method 400 may include additional, fewer, and / or different operations.

[0063] Method 400 includes coupling an intake manifold to the cylinder head of a dual-fuel engine system capable of having a first fuel injector extending into the cylinder head. In other embodiments, Method 400 includes coupling an intake manifold to the cylinder head of a different type of engine system having any of the above-described types of engine systems. The first fuel injector is configured to supply a quantitative amount of the first fuel. Furthermore, this method includes inserting a second fuel injector into the cylinder head through the intake manifold such that the second fuel injector is oriented to spray a second fuel identical to or different from the first fuel into an intake port defined by the cylinder head.

[0064] In operation 402, the intake manifold is coupled to the cylinder head. In some embodiments, operation 402 includes machining the cylinder head of a single-fuel compression-ignition engine system to define an injector bore extending into the intake port of the cylinder head. In other embodiments, operation 402 includes preparing a replacement cylinder head having at least one injector bore for supporting a second fuel injector internally. In such an example, operation 402 may include removing the existing cylinder head from the engine system and coupling the replacement cylinder head to the engine block. Furthermore, operation 402 may include forming an intake manifold having the features described herein with respect to intake manifold 202 or intake manifold 302, respectively, as shown in Figures 4 and 5. For example, operation 402 may include casting or otherwise forming at least one injector mount (e.g., at least one injector support tube) into the manifold body. Furthermore, operation 402 may include connecting the intake manifold to the cylinder head using bolts or other types of mechanical fasteners.

[0065] In operation 404, the second fuel injector is inserted into the cylinder head through the intake manifold so that the second fuel injector is oriented to spray a second fuel, which is the same as or different from the first fuel, into the intake port defined by the cylinder head. In some embodiments, operation 404 includes aligning the central axis of the second fuel injector with the central axis of the injector mount on the intake manifold and pressing the second fuel injector into the injector mount.

[0066] In some embodiments, operation 404 further includes sealingly engaging a second fuel injector with respect to the cylinder head and intake manifold. For example, operation 404 may include sealingly engaging a first seal member between the second fuel injector and the intake manifold in the axial direction. Furthermore, operation 404 may include engaging a second seal member located between the second fuel injector and the intake manifold in the axial direction and having a larger cord diameter than the first seal member. In some embodiments, operation 404 further includes sealingly engaging a third seal member between the second fuel injector and the cylinder head in the radial direction to prevent leakage of charge air and / or second fuel from the cylinder head.

[0067] In operation 406, the second fuel injector is rotatably aligned with respect to the intake manifold and the cylinder head. In some embodiments, operation 406 includes rotating the second fuel injector so that the nozzle of the second fuel injector is oriented to spray fuel toward the intake opening of the intake port of the cylinder head and / or toward the rear surface of the valve head of the intake valve. Operation 406 may include rotating the second fuel injector within the injector mount before inserting the second fuel injector and / or while inserting the second fuel injector into the injector mount. In some embodiments, operation 406 includes rotatably aligning the fuel injector mounting flange with respect to a rotational alignment indicator on the manifold body and / or a rotational support element coupled to the manifold body.

[0068] In operation 408, the rotation support element is coupled to the second fuel injector. In some embodiments, operation 408 includes engaging a pair of extension elements (e.g., forks) of the rotation support element with both sides (e.g., a pair of substantially parallel side surfaces) of the fuel injector mounting flange of the second fuel injector. In such embodiments, operation 408 may include preventing relative rotation between the two by slidably engaging the extension elements with the injector mounting flange. Furthermore, operation 408 may further include coupling the rotation support element to the intake manifold by inserting a fastener into the manifold body through the rotation support element.

[0069] While embodiments have been described above with reference to Figures 1 to 10, various modifications and additions to these embodiments are anticipated and are deemed to be included within the scope of this disclosure.

[0070] Furthermore, the technology may include, but is not limited to, the features and combinations of features listed in the following paragraphs. It should also be understood that the following paragraphs should not be construed as limiting the claims appended to this specification or as requiring all such features to necessarily be included within the scope of such claims. A. A dual fuel engine system, The cylinder head that defines the intake port, The intake manifold is coupled to the cylinder head, A first fuel injector extending into the cylinder head and configured to supply a fixed amount of first fuel, A second fuel injector extending through the intake manifold into the cylinder head and configured to supply a quantitative amount of second fuel, the second fuel injector being oriented to spray the second fuel into the intake port, A dual-fuel engine system equipped with this system. B. The dual-fuel engine system according to paragraph A, further comprising an intake valve at least partially disposed within a cylinder head, the intake valve having a valve head defining a rear surface facing an intake port, and a second fuel injector oriented to spray a second fuel toward the rear surface. C. The dual-fuel engine system described in paragraph B, wherein the second fuel injector is oriented substantially perpendicular to the valve stem of the intake valve. D. A dual fuel engine system according to any one of the preceding paragraphs, wherein the cylinder head defines an intake opening at the end of an intake port, and the dual fuel engine system further comprises an intake valve having a valve head configured to engage with the cylinder head at this intake opening, and a second fuel injector oriented to spray a second fuel toward the intake opening. E. A dual-fuel engine system as described in any one of the preceding paragraphs, wherein the second fuel injector is an offset fuel injector configured to supply a fixed amount of the second fuel toward only one side of the second fuel injector. F. A dual-fuel engine system according to any one of the preceding paragraphs, further comprising a rotational support element configured to fix a second fuel injector in a single rotational position relative to the cylinder head. G. The dual-fuel engine system described in paragraph F, wherein the rotating support element is a fuel injector clamp that engages with the second fuel injector outside the intake manifold. H. A dual-fuel engine system as described in any one of the preceding paragraphs, wherein the second fuel injector is configured to produce an asymmetrical spray pattern of the second fuel. I. A dual-fuel engine system according to any one of the preceding paragraphs, further comprising a fuel rail assembly coupled to an intake manifold and fluid-coupled to a second fuel injector. J. A dual-fuel engine system as described in any one of the preceding paragraphs, wherein the intake manifold has an injector mount that penetrates the interior, and the injector mount separates the airflow plenum of the intake manifold from a second fuel injector. K. A dual-fuel engine system described in any one of the preceding paragraphs, wherein the second fuel is different from the first fuel. L. A dual-fuel engine system as described in any one of the preceding paragraphs, further comprising an engine block defining a cylinder, wherein the first fuel injector extends into the cylinder. M. A first sealing member disposed between the second fuel injector and the intake manifold in the axial direction, A second seal member disposed axially between a second fuel injector and an intake manifold, wherein the second cord diameter of the second seal member is larger than the first cord diameter of the first seal member. A dual-fuel engine system further comprising the features described in any one of the preceding paragraphs. N. Intake manifold, The manifold body defines the airflow plenum that penetrates the interior, An intake manifold comprising an injector mount extending at least partially through an airflow plenum, the injector mount defining a bore extending through both ends of a manifold body, the bore being sized to receive a fuel injector inside, and the injector mount comprising a tube that fluidly separates the bore from the airflow plenum along the entire axial length of the bore. O. The intake manifold described in paragraph N, wherein the injector mount is integrally formed with the intake manifold as a single structural body from a single piece of material. P. The intake manifold according to paragraph N or O, comprising a step for separating the first part of the bore from a second part of the bore, wherein the first part has a smaller diameter than the second part. Q. The intake manifold according to paragraph P, wherein step defines a first axially facing seal surface of the injector mount, and the injector mount further defines a second axially facing seal surface disposed along the periphery of the bore and axially spaced apart from the first axially facing seal surface. R. The intake manifold as described in paragraph P, wherein a first portion of the bore extends through a first end of the manifold body, and a second portion of the bore extends through a second end of the manifold body located on the opposite side of the first end. S. The intake manifold described in any one of paragraphs N to R, further defining the rail assembly mount for supporting the fuel rail assembly on the manifold body. T. A method for manufacturing a dual-fuel engine system, A step of connecting an intake manifold to the cylinder head of a dual-fuel engine system, wherein the dual-fuel engine system includes a first fuel injector that extends into the cylinder head and is configured to supply a fixed amount of a first fuel; The steps include inserting a second fuel injector into the cylinder head through the intake manifold so that the second fuel injector is oriented to spray a second fuel into the intake port defined by the cylinder head, Methods that include... U. The method according to paragraph T, further comprising the step of oriented the second fuel injector so that the second fuel injector quantifies the supply of the second fuel toward the rear surface of the valve head of the intake valve of a dual fuel engine system. V. The method according to paragraph T or U, further comprising the step of aligning a second fuel injector in the rotational direction with a fuel injector support element. The method according to paragraph V, further comprising the step of coupling a rotational support element to the intake manifold and the second fuel injector to fix the rotational position of the second fuel injector relative to the cylinder head. X. The step of coupling a rotating support element to the second fuel injector is: The steps include engaging the forks of the rotational support element with both sides of the fuel injector mounting flange of the second fuel injector, The steps include: connecting a rotational support element to the intake manifold, The method described in paragraph W, including the method described in paragraph W. Y. The step of inserting the second fuel injector is, The steps include engaging the first sealing member between the second fuel injector and the intake manifold in the axial direction, The steps include engaging a second sealing member having a larger cord diameter than the first sealing member between the second fuel injector and the intake manifold in the axial direction, A method described in any one of paragraphs T through W, including the method described in paragraph T through W.

[0071] Where used herein in relation to numerical ranges, the terms “approximately,” “about,” “substantially,” and similar terms generally mean a range of + / - 10% of the disclosed numerical value unless otherwise specified. Where used herein in relation to structural features (e.g., shape, size, orientation, direction, relative position, etc.), the terms “approximately,” “about,” “substantially,” and similar terms are intended to include minor structural variations that may occur as a result of, for example, a manufacturing or assembly process, and are intended to have a broad meaning consistent with the general and accepted usage by those skilled in the art relating to the subject matter of this disclosure. Accordingly, these terms should be interpreted as suggesting that minor or insignificant modifications or variations of the subject matter described and claimed are considered to fall within the scope of this disclosure as set forth in the appended claims.

[0072] The term “exemplary” and its variations, as used in this specification to describe various embodiments, are intended to indicate that such embodiments are possible examples, representative examples, or illustrations of possible embodiments (and such term is not necessarily intended to imply that such embodiments are particularly good or best examples).

[0073] In this specification, the term “joined” and its variations mean joining two members directly or indirectly to one another. Such joining can be static (e.g., permanent or fixed) or movable (e.g., removable or detachable). Such joining can be achieved by the two members being directly joined to each other, by the two members being joined to each other using separate intervening members, by any additional intervening members being joined to each other, or by the two members being joined to each other using an intervening member that forms integrally with one of the two members as a single, unified structural body. Where “joined” or its variations are modified by an additional term (e.g., directly joined), the general definition of “joined” as set forth above is modified by the plain literal meaning of the additional term (e.g., “directly joined” means that two members are joined without the use of any separate intervening members), resulting in a narrower definition than the general definition of “joined” as set forth above. Such joining can be mechanical, electrical, or fluid.

[0074] The terms used herein to indicate the location of elements (e.g., “top,” “bottom,” “upper,” “downward”) are used solely to describe the orientation of various elements in these drawings. It should be noted that the orientation of various elements may differ in other exemplary embodiments, and such variations are intended to be included in this disclosure.

[0075] While drawings and descriptions may indicate a specific order of method steps, the order of such steps may differ from that shown and described above unless otherwise specified. Furthermore, unless otherwise specified above, two or more steps may be performed simultaneously or partially simultaneously.

[0076] It is important to note that any element disclosed in one embodiment can be incorporated into or used in conjunction with any other embodiment disclosed herein. While only one example has been given above of an element from one embodiment being incorporated into or used in conjunction with another embodiment, it should be understood that other elements from various embodiments can also be incorporated into or used in conjunction with any of the other embodiments disclosed herein. [Explanation of Symbols]

[0077] 100 Dual Fuel Engine System 102 Cylinder head 104 Intake Port 105 Engine block, intake channel 106 First fuel injector 108 First fuel 110 Second fuel 112 Cylinder 114 Intake opening 116 Injector Bore 117 Cylinder head assembly 118 External surface 119 Airflow direction 120 Intake valve 122 Valve Stem 124 Valve Head 126 Posterior surface 128 Anterior surface 200 Modification Systems 202 Intake Manifold 204 Second fuel injector 206 Fuel Rail Assembly 208 Manifold Body 210 Injector Mount 211 Airflow Plenum 212 Bore 213 End 214 Tube 216 steps 218 Part 1 220 Part 2 222 First end 224 Second end 226 First axially facing sealing surface 228 Central axis 230 Second axially facing sealing surface 232 Rail Assembly Mount 236 Mounting Elements 238 Injector Body 240 Tip part 242 nozzles 244 Electronically controlled solenoid valve 246 Central axis 248 angle 250 First sealing member 251 First radial gap 252 Second sealing member 253 Second radial gap 254 Third sealing member 256 Second cord diameter 258 First cord diameter 260 Rotating support element 262 Fuel Injector Clamp 264 Fuel injector mounting flange 266 First pair of parallel side surfaces 268 Support base 269 ​​Aperture 270 Extension 272 Second pair of parallel side surfaces 302 Intake Manifold 310 Injector Mount 314 Tube

Claims

1. It is a dual-fuel engine system, The cylinder head that defines the intake port, An intake manifold coupled to the cylinder head, A first fuel injector extending into the cylinder head and configured to supply a fixed amount of first fuel, A second fuel injector that extends through the intake manifold into the cylinder head and is configured to supply a quantitative amount of a second fuel, the second fuel injector being oriented to spray the second fuel into the intake port, A dual-fuel engine system equipped with this system.

2. The dual-fuel engine system according to claim 1, further comprising an intake valve at least partially disposed within the cylinder head, the intake valve having a valve head defining a rear surface facing the intake port, and the second fuel injector being oriented to spray the second fuel toward the rear surface.

3. The dual-fuel engine system according to claim 2, wherein the second fuel injector is oriented substantially perpendicular to the valve stem of the intake valve.

4. The dual fuel engine system according to claim 1, wherein the cylinder head defines an intake opening at the end of the intake port, and the dual fuel engine system further comprises an intake valve having a valve head configured to engage with the cylinder head at the intake opening, and the second fuel injector is oriented to spray the second fuel toward the intake opening.

5. The dual-fuel engine system according to claim 1, wherein the second fuel injector is an offset fuel injector configured to supply a fixed amount of the second fuel toward only one side of the second fuel injector.

6. The dual-fuel engine system according to claim 1, further comprising a rotational support element configured to fix the second fuel injector in a single rotational position relative to the cylinder head.

7. The dual-fuel engine system according to claim 6, wherein the rotating support element is a fuel injector clamp that engages with the second fuel injector outside the intake manifold.

8. The dual-fuel engine system according to claim 1, wherein the second fuel injector is configured to produce an asymmetric spray pattern of the second fuel.

9. The dual-fuel engine system according to claim 1, further comprising a fuel rail assembly coupled to the intake manifold and fluidly coupled to the second fuel injector.

10. The dual-fuel engine system according to claim 1, wherein the intake manifold includes an injector mount that penetrates the interior, and the injector mount separates the airflow plenum of the intake manifold from the second fuel injector.

11. The dual-fuel engine system according to claim 1, wherein the second fuel is different from the first fuel.

12. The dual-fuel engine system according to claim 1, further comprising an engine block defining a cylinder, wherein the first fuel injector extends into the cylinder.

13. A first sealing member is disposed in the axial direction between the second fuel injector and the intake manifold, A second seal member disposed in the axial direction between the second fuel injector and the intake manifold, wherein the second cord diameter of the second seal member is larger than the first cord diameter of the first seal member, The dual fuel engine system according to claim 1, further comprising:

14. It is an intake manifold, The manifold body defines the airflow plenum that penetrates the interior, An intake manifold comprising an injector mount extending at least partially through the airflow plenum, wherein the injector mount defines a bore extending through both ends of the manifold body, the bore being sized to receive a fuel injector, and the injector mount comprising a tube along the entire axial length of the bore for fluidic separation of the bore from the airflow plenum.

15. The intake manifold according to claim 14, wherein the injector mount is integrally formed with the intake manifold as a single structural body from a single piece of material.

16. The intake manifold according to claim 14, wherein the injector mount comprises a step of separating the first portion of the bore from the second portion of the bore, the first portion having a smaller diameter than the second portion.

17. The intake manifold according to claim 16, wherein the step defines a first axially facing seal surface of the injector mount, and the injector mount further defines a second axially facing seal surface disposed along the periphery of the bore and axially spaced apart from the first axially facing seal surface.

18. The intake manifold according to claim 16, wherein the first portion of the bore extends through the first end of the manifold body, and the second portion of the bore extends through the second end of the manifold body located on the opposite side of the first end.

19. The intake manifold according to claim 14, wherein the manifold body further defines a rail assembly mount for supporting a fuel rail assembly on the manifold body.

20. A method for manufacturing a dual-fuel engine system, A step of connecting an intake manifold to the cylinder head of the dual-fuel engine system, wherein the dual-fuel engine system includes a first fuel injector that extends into the cylinder head and is configured to supply a fixed amount of a first fuel; The steps include inserting the second fuel injector into the cylinder head through the intake manifold so that the second fuel injector is oriented to spray the second fuel into the intake port defined by the cylinder head, Methods that include...

21. The method according to claim 20, further comprising the step of oriented the second fuel injector so as to supply a quantitative amount of the second fuel toward the rear surface of the valve head of the intake valve of the dual fuel engine system.

22. The method according to claim 20, further comprising the step of aligning the second fuel injector in the rotational direction with respect to the intake manifold.

23. The method according to claim 22, further comprising the step of connecting a rotational support element to the intake manifold and the second fuel injector to fix the rotational position of the second fuel injector relative to the cylinder head.

24. The step of connecting the rotating support element to the second fuel injector is: The steps include engaging the forks of the rotating support element with both sides of the fuel injector mounting flange of the second fuel injector, The steps include: connecting the rotation support element to the intake manifold; The method according to claim 23, including the method described in claim 23.

25. The step of inserting the second fuel injector is, The steps include engaging the first sealing member between the second fuel injector and the intake manifold in the axial direction, The steps include engaging a second sealing member having a larger cord diameter than the first sealing member between the second fuel injector and the intake manifold in the axial direction, The method according to claim 20, including the method described in claim 20.

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