Supply assembly for a gaseous fuel engine

Abstract

The invention relates to a supply assembly (1) for a gaseous fuel engine (70). In order to provide an effective means for the precise lubrication of fuel injectors of a gaseous fuel engine, the invention provides a supply assembly (1) comprising: - a fuel supply system (10) comprising a fuel rail (12) for delivering gaseous fuel and a plurality of injector units (13), each injector unit (13) comprising a fuel injector (20) which is at least indirectly connected to the fuel rail (12) and which is adapted to inject fuel into the engine (70), and - a lubricant supply system (30) comprising at least one lubricant doser (31) having an outlet port (38), the lubricant doser (31) being adapted to controllably release liquid lubricant (L) into an injector unit (13) through the outlet port (38) and being mounted to the injector unit (13).

Description

Technical Field

[0001] This invention relates to a supply assembly for a gas-fueled engine, and to a fuel rail assembly for a gas-fueled engine. Background Technology

[0002] For automotive applications, hydrogen engines are considered a promising alternative to gasoline or diesel engines because their emissions consist primarily of water. However, using “dry” hydrogen (i.e., without any additional lubricant) can pose a risk of wear to components of the engine system. All moving parts in the system, such as pressure regulators, injectors, etc., are prone to wear. Similar problems arise in internal combustion engines using other types of gaseous fuels, such as natural gas. Specifically, the lifespan and operational reliability of fuel injectors used with gaseous fuels can be severely affected. For fuel injectors installed for direct fuel injection, the lack of lubrication is even more problematic because they face higher temperatures, leading to excessive wear primarily at the needle valve / seat interface of the injector nozzle. A lubrication system has been proposed that releases liquid lubricant into the fuel supply system upstream of the fuel injector or into the fuel injector itself. However, such lubricant release faces various challenges. Specifically, it is desirable to precisely control the amount of lubricant and avoid any over-lubrication of the injector, which can lead to adhesion of moving injector components.

[0003] Technical issues

[0004] Therefore, one object of the present invention is to provide an effective device for precise lubrication of fuel injectors for gas fuel engines.

[0005] This problem is solved by the supply component as described in claim 1 and the fuel rail component as described in claim 19. Summary of the Invention

[0006] This invention provides a supply assembly for a gas-fueled engine. Hereinafter, a gas-fueled engine is an internal combustion engine that operates on a gaseous fuel, such as coal gas, producer gas, biogas, landfill gas, natural gas, or hydrogen. This is particularly applicable to hydrogen internal combustion engines. Specifically, the engine can be a drive engine for a vehicle (such as a road vehicle), but other applications are possible. As explained below, the supply assembly has the function of supplying fuel and / or lubricant to the engine and / or components associated with the engine.

[0007] The supply assembly includes a fuel supply system comprising a fuel rail for delivering gaseous fuel and multiple injector units, each injector unit including a fuel injector at least indirectly connected to the fuel rail and adapted to inject fuel into the engine. Since gaseous fuel engines can be adapted to different gaseous fuels, so too can the fuel supply system and fuel rail. The material used for the fuel supply system can be selected based on the characteristics of the gaseous fuel. In the case of hydrogen fuel, stainless steel may be a preferred material. During operation, the gaseous fuel in the fuel supply system may be under elevated pressures, for example up to 40 bar or higher, in which case the mechanical stability of the fuel supply system needs to be adjusted accordingly. Multiple injector units are connected to the fuel rail, each injector unit including a fuel injector. Preferably, each injector unit includes only one fuel injector. The fuel injector may be directly connected to the fuel rail or indirectly connected to the fuel rail, i.e., via another element, specifically via an injector base. These injector units can be said to branch off from the fuel rail. The interior of the fuel rail is in fluid communication with each injector unit, thus the interior of the fuel rail is in direct or indirect communication with the interior of each fuel injector.

[0008] Fuel injectors are adapted to inject gaseous fuel into an engine. This can specifically refer to direct fuel injection, whereby the fuel injector is adapted to inject fuel directly into the combustion chamber of the corresponding engine cylinder. However, fuel injectors can also be configured for other types of injection, i.e., for injection into an inlet manifold, inlet line, or any other element through which air is supplied to the engine. Fuel injectors for gaseous fuels, particularly for hydrogen-containing fuels, are known in the art, and the details of the fuel injectors are not important in the context of this invention. As an example, a fuel injector can extend along an injector axis from a proximal end face to a distal end face facing the engine. It can include an injector body defining a fuel passage that extends through the injector body and communicates with an outlet opening disposed on the distal end face of the injector body. Typically, the outlet opening can be closed by a needle valve cooperating with a valve seat. It should be understood that the number of fuel injectors in the supply assembly can correspond to the number of cylinders in the engine, but multiple fuel injectors for a single cylinder may also be present. Preferably, all fuel injectors are identical. If the injector unit includes any additional components besides the fuel injector, this also applies to the injector unit.

[0009] The supply assembly also includes a lubricant supply system comprising at least one lubricant metering device with an outlet port, the metering device being adapted to controllably release liquid lubricant into and onto the injector unit via the outlet port. At least one function of the lubricant supply system is to provide lubrication for at least one fuel injector, preferably for all fuel injectors. Furthermore, it can also provide lubrication for other components. It includes at least one lubricant metering device, preferably multiple lubricant metering devices, i.e., one lubricant metering device for each injector unit. The lubricant metering device includes an outlet port and is adapted to controllably release liquid lubricant through the outlet port. Generally, liquid lubricants may also be referred to as lubricating oil or simply as oil. Its function is to provide lubrication for at least one component of the engine and / or supply system. Various lubricants can be used in the supply system of the present invention, which may include natural and / or synthetic components. One possible lubricant could be engine oil, but other oils may also be used. Although the lubricant is referred to as "liquid," this does not preclude it from containing small amounts of solid particles as additives or as (undesirable) impurities. "Controllable" means that the design of the lubricant metering device allows for control over the timing and amount of lubricant release, with the precision of control varying between different implementation schemes.

[0010] The lubricant metering device is mounted to the injector unit. Therefore, it is very close to the injector unit, and a portion of the lubricant metering device may even be located within the injector unit. In embodiments, at least a portion of the lubricant metering device may be non-removably connected to the injector unit. It is even possible that at least one component of the lubricant metering device and at least one component of the injector unit are made as a single piece, preferably of metal. Preferably, the outlet port is configured to release lubricant into the injector unit. It may communicate directly with the cavity of the injector unit designed to contain gaseous fuel. In any case, the possible dead volume between the outlet port of the lubricant metering device and the injector unit is greatly reduced, preferably to zero. Such a dead volume could potentially be a source of undesirable lubricant leakage because the lubricant released from the dead volume cannot be directly controlled by the lubricant metering device. Such undesirable lubricant release could potentially lead to over-lubrication of the fuel injector, which is highly unlikely due to the construction of the present invention. Moreover, it is advantageous to release the lubricant into the injector unit rather than into the fuel rail. On the one hand, this prevents lubricant residue from remaining in the fuel rail, which requires no lubrication. On the other hand, the inventive concept allows for the delivery of lubricant to a specific fuel injector, making lubrication more precise. The fuel rail and at least one lubricant metering device can be considered part of the fuel rail assembly of this invention, which will be discussed further below.

[0011] It is conceivable that the fuel injector is directly connected to the fuel rail, in which case the lubricant metering device releases lubricant directly into the fuel injector. In embodiments, at least one injector unit includes an injector base through which the fuel injector is connected to the fuel rail, and the lubricant metering device is adapted to release lubricant into the injector base. The injector base can be secured to the fuel rail, preferably in a non-removable and hermetically sealed manner, such as by welding or brazing. It can be made of the same material as the fuel rail (e.g., stainless steel). In practice, the base can be considered an integral accessory to the fuel rail. That is, multiple injector bases are secured to the fuel rail before the fuel rail and injectors are subsequently assembled into the engine. In other embodiments, the fuel rail and injector bases can be manufactured as a single unit.

[0012] In some embodiments, the fuel injector may be directly connected to the injector base. In other embodiments, an additional element, referred to herein as an injector interface, is inserted between the injector base and the injector. Alternatively, the injector interface may also be considered part of the injector base. It should be understood that the injector base includes a cavity or channel adapted to receive fuel and guide fuel from the fuel rail to the fuel injector. This may be referred to as a base channel. A lubricant metering device is adapted to release lubricant into the injector base, for example, directly into the base channel. The base may also include a base lubricant channel connected to the base channel, and the lubricant metering device may release lubricant into this base lubricant channel. Preferably, the lubricant metering device is mounted to the injector base. Therefore, the fuel injector can be removed and replaced without removing the lubricant metering device. At least one injector base (including the injector interface, if present) is considered part of the aforementioned fuel rail assembly. On the other hand, a fuel injector connected to the injector base may not be considered part of the fuel rail assembly.

[0013] A lubricant metering device can operate in a manner similar to fuel injectors known in the art; that is, it can include a single valve that allows lubricant release while the single valve remains open. In this case, the amount or volume of lubricant released depends primarily on the opening time of the corresponding valve, which requires precise timing control of that valve. According to another embodiment, at least one lubricant metering device is a volumetric metering device, comprising a pumping chamber communicating with an outlet port and a pumping plunger adapted to discharge lubricant from the pumping chamber to release a defined release volume of lubricant into the injector unit during a release process. During operation, the pumping chamber contains lubricant at least temporarily. During the release process, the pumping plunger extrudes or discharges lubricant from the pumping chamber communicating with the outlet port. Thus, movement of the pumping plunger causes lubricant to be released from the outlet port. Specifically, a defined release volume can be released. In other words, the volumetric metering device is designed to allow the release of a defined release volume of lubricant only during a single release process, which may also be referred to as a release event, etc. The pumping chamber is preferably adapted to receive and temporarily store lubricant between two release processes. That is, the volumetric metering device can perform the release process and can be reloaded or refilled later by receiving the corresponding amount of lubricant. The latter process can be referred to as the intake process. It should be understood that the “defined” volume can vary to some extent depending on various factors. However, the volume preferably varies by less than 10% or less than 5% between different release processes. The defined release volume allows for very precise lubrication while avoiding over-lubrication and under-lubrication. If multiple lubricant metering devices are volumetric metering devices, it is preferable that the release volume is the same for each volumetric metering device. Preferably, the release volume is less than 20 mm³, more preferably less than 10 mm³, and even more preferably less than 5 mm³. The volumetric metering device can also be referred to as a pumping metering device.

[0014] Preferably, the supply assembly is adapted to simultaneously initiate the release process in multiple lubricant metering units. In other words, the release process occurs simultaneously in multiple lubricant metering units. Preferably, this involves all lubricant metering units. This embodiment is advantageous for the lubrication process and its control. For example, the release process schedule is simpler because it is the same for several (or all) metering units. Furthermore, compared to embodiments where each metering unit has its own schedule, the number of components and / or the size of some components can be reduced. It should be noted that at least some control components (e.g., control units or control software) may not be part of the lubricant supply system, but may be part of, for example, a higher-level component that controls both the lubricant supply system and the fuel supply system.

[0015] According to a preferred embodiment, the lubricant metering device includes a metering body having a metering chamber in which a pumping plunger is movable along a plunger axis between a proximal position and a distal position, such that the volume of a pumping chamber, partially defined by the distal portion of the pumping plunger, is greater at the proximal position than at the distal position. The lubricant metering device also includes an inlet port communicating with the pumping chamber and an outlet port communicating with the pumping chamber via an outlet valve. The metering body may include one or more connected (preferably fixedly connected) components. Within the metering body is the metering chamber. The pumping plunger is movably disposed within the metering chamber. To facilitate movement of the pumping plunger along its axis, the pumping plunger may be guided by an inner wall of the metering body defining the metering chamber. At least a portion of the metering chamber can be considered a cylindrical cavity in which the pumping plunger is disposed. The pumping plunger is movable between a proximal position and a distal position, which are positions relative to the plunger axis. As the pumping plunger moves from the proximal position to the distal position, the volume of the pumping chamber decreases. As the pumping plunger moves from the distal position to the proximal position, the volume increases. This pumping chamber, which can be at least partially formed by the metering chamber, is partially defined by the distal portion of the pumping plunger. Typically, it is also partially defined by the metering body. Because the pumping plunger can move within the metering chamber, the gap between the pumping plunger and the wall of the metering chamber is a potential leakage point. This problem can be mitigated if an elastomeric element is attached to the pumping plunger and inserted between the pumping plunger and the metering body. Such an elastomeric element can be an elastomeric O-ring arranged circumferentially around the pumping plunger. It can be made of rubber or another suitable elastomeric material. Although the elastomeric element may increase friction, it provides a sealing effect that would otherwise only be achieved by increasing the length of the pumping plunger along its axis, thus increasing the length of possible leakage paths. However, increasing the length of the pumping plunger will also increase the overall size of the lubricant metering unit.

[0016] In this embodiment, the lubricant metering device further includes an inlet port communicating with the pumping chamber, and an outlet port communicating with the pumping chamber via an outlet valve. The inlet port is adapted to connect to a lubricant source or lubricant supply source, i.e., the lubricant metering device can receive lubricant through the inlet port. The delivery of lubricant from the inlet port to the pumping chamber can be controlled in various ways, which will be discussed below. The delivery of lubricant from the inlet port to the pumping chamber coincides with an increase in the volume of the pumping chamber, and therefore with a movement of the pumping plunger from a distal position to a proximal position. The delivery of lubricant from the pumping chamber to the outlet port is controlled by the outlet valve. Typically, the outlet valve can be any type of valve. Preferably, it at least defines a closed position and an open position, in which the delivery of lubricant from the pumping chamber to the outlet port is prevented, and in the open position, the delivery of lubricant is permitted. The delivery of lubricant from the pumping chamber to the outlet port coincides with a decrease in the volume of the pumping chamber, and therefore with a movement of the pumping plunger from a proximal position to a distal position. It should be understood that the lubricant metering device described herein can be a volumetric metering device. During the release process, the outlet valve opens while the pumping plunger moves to the distal position and discharges lubricant from the pumping chamber. If the proximal and distal positions are well defined, the movement of the pumping plunger results in the release of the defined release volume. Similarly, when the outlet valve closes and the pumping plunger moves to the proximal position, a dose of lubricant corresponding to the release volume can be delivered from the inlet port to the pumping chamber.

[0017] In one embodiment, the inlet port communicates with the pumping chamber via an inlet valve. In this case, the delivery of lubricant from the inlet port to the pumping chamber is controlled by the inlet valve. Typically, the inlet valve can be any type of valve. Preferably, it defines at least a closed position and an open position, in which the delivery of lubricant from the inlet port to the pumping chamber is prevented, and in the open position, the delivery of lubricant is permitted. In other embodiments, the inlet port communicates with the pumping chamber via an inflow opening disposed adjacent to the pumping chamber, such that the pumping plunger blocks the inflow opening at a distal position and opens the inflow opening at a proximal position. In this embodiment, there is no dedicated "inlet valve," but the function of an inlet valve is performed by the pumping plunger. As the pumping plunger moves between the proximal and distal positions, the inflow opening is alternately blocked and opened by the pumping plunger. The inflow opening is disposed adjacent to the pumping chamber such that the pumping plunger or a portion of the pumping plunger can block the inflow opening. Possibly, the inflow opening may represent a contraction or narrowing between the inlet port and the pumping chamber. That is, the cross-section of the inflow opening can be reduced relative to the adjacent cavity that communicates with or constitutes the inlet port. In particular, the inflow opening can be realized through micropores, which can have a diameter of a few micrometers to several hundred micrometers. However, larger diameters are also possible.

[0018] The metering unit body may include an external portion, which may also be referred to as the metering unit housing. This external portion may include two elements, which may be referred to as a housing shell and a housing cover, at least in some embodiments. These two portions may be connected, for example, by a threaded connection. The metering unit housing may include an internal assembly, which may include an internal portion of the metering unit body as well as a pumping plunger and other components (e.g., an inlet valve and / or an outlet valve). The metering unit cavity may be at least partially disposed within the internal assembly, but may also be partially disposed between the internal assembly and the metering unit housing. The internal assembly may include at least two portions, for example, connected by a press fit. A first portion may be referred to as a plunger portion and may be defined at a portion of the metering unit cavity, particularly at the portion where the pumping plunger is disposed. A second portion may be referred to as a valve seat portion and may constitute a valve seat for the outlet valve. The external portion may be pre-assembled before the internal assembly is placed within a portion of the metering unit housing (e.g., the housing shell), after which these portions of the housing are joined to encapsulate the internal assembly.

[0019] In one embodiment, at least a portion of the metering body is non-removably connected to the injector base. This can preferably be the aforementioned housing shell. It can be manufactured as a separate element, which is subsequently bonded to the injector base, for example by brazing, before the internal components are placed inside the housing shell. Thus, a robust connection to the injector base can be established without exposing potentially heat-sensitive parts of the internal components to the elevated temperatures of the brazing process. The bonding process is preferably performed in a hermetically tight manner, i.e., by providing a continuous metallurgical bond along the interface. In another embodiment, at least a portion of the metering body and the injector base are made from a single piece, preferably from a single piece of metal. In this case, there may be no significant difference between the corresponding portions of the injector base and the metering body.

[0020] To facilitate lubricant distribution within the injector unit, a perforated outlet cap can be provided at the outlet port. The outlet cap is configured such that lubricant can only be released from the outlet port through the outlet cap. The outlet cap is perforated, meaning it includes multiple holes or through-holes through which the lubricant is released. This promotes the formation of small droplets, which aids in the distribution of lubricant within the gaseous fuel. The outlet cap can be, for example, a single metal body with multiple through-holes or a wire mesh.

[0021] Preferably, the pumping volume of the pumping plunger moving between the proximal and distal positions is less than 20 mm. 3 Preferably less than 10mm 3 More preferably less than 5mm 3The pumping volume is the volume moved by the pumping plunger as it moves from a proximal position to a distal position. It corresponds to the distance between these positions multiplied by the cross-section of the pumping plunger adjacent to the pumping chamber. Except for volume changes due to the compressibility of the lubricant, the pumping volume can be the same as the release volume. In other words, in this embodiment, each movement of the pumping plunger results in a release process in which only a small amount of lubricant is released. This small amount is considered optimal for the lubrication of the fuel injector.

[0022] One embodiment provides that the inlet valve and outlet valve are check valves, the inlet valve being adapted to open in response to overpressure at the inlet port relative to the pumping chamber, and the outlet valve being adapted to open in response to overpressure in the pumping chamber relative to the outlet port. Each check valve may include a fixed valve seat and a movable valve member that sealably engages the valve seat in the closed position of the check valve. The valve member is resiliently biased to the closed position, for example by a spring element. At least one of the valve seat and valve member may include a resilient sealing portion that engages with another element in the closed position to provide an improved seal. It should be understood that each of the inlet valve and outlet valve may be adapted to open only when the corresponding overpressure exceeds a defined opening threshold. When the pumping plunger moves to the distal position, the pressure in the pumping chamber increases and may exceed the pressure at the inlet port, thus the inlet valve will close or remain closed. On the other hand, the outlet valve opens due to the increased pressure. It should be understood herein that the outlet port is in fluid communication with the injector unit and is therefore typically subjected to a considerable pressure of the fuel gas. In other words, for the outlet valve to open, the pressure in the pumping chamber must be at least greater than the gas pressure at the outlet port. Conversely, if the pressure at the inlet port exceeds the pressure in the pumping chamber (plus the aforementioned opening threshold), the inlet valve opens. In this case, the outlet valve should close, therefore the opening threshold for the outlet valve must be set accordingly. To open the inlet valve, the pressure at the inlet port can be increased, in which case the pumping plunger can be "passively" moved to a proximal position by the fluid pressure in the pumping chamber. Alternatively, the pressure in the pumping chamber can be reduced by actively moving the pumping plunger to a proximal position.

[0023] There are various possible ways to move the pump plunger toward a distal position. The plunger can be moved by an electromechanical actuator of any suitable technology. For example, a magnetic field can be generated by a magnetic coil / spindle in the metering unit. Alternatively, a hydraulic actuation device can be used. A preferred embodiment provides that the metering unit cavity includes a control chamber on the proximal face of the pump plunger, which communicates with a control port, and the pump plunger can be moved to a distal position by fluid pressure at the control port. This embodiment relies on fluid actuation of the pump plunger. The control chamber (also referred to as the control portion) is a portion of the metering unit cavity disposed on the proximal face of the pump plunger, i.e., on the opposite side relative to the pumping chamber. The control chamber may be partially defined by the metering unit body and the pump plunger. It communicates with a control port, which can also be considered part of the control chamber at least in some embodiments. When the fluid pressure at the control port changes, the pressure acting on the proximal face of the pump plunger also changes. For example, if the pressure in the pumping chamber remains constant while the pressure in the control chamber increases, this can result in a force difference that moves the pumping plunger to a distal position. This fluid actuation of the plunger simplifies the layout of the lubricant metering device. Specifically, a dedicated actuator (e.g., an electromagnetic actuator) is not required, and therefore electrical connections are not needed. Furthermore, fluid actuation results in a more robust lubricant metering device (which is less prone to failure).

[0024] As explained, fluid actuation depends on the force difference between the proximal and distal faces of the plunger. This force difference may be due to a pressure difference. Alternatively, it may be due to pressure acting on different effective areas. According to one embodiment, the proximal portion of the pumping plunger, located adjacent to the control chamber, has a larger cross-section perpendicular to the plunger axis than the distal portion. It should be understood that, with respect to the plunger's movement parallel to its axis, the cross-section perpendicular to the plunger axis represents the effective area with respect to pressure. In this embodiment, the cross-section of the proximal portion subjected to pressure in the control chamber is larger than the cross-section of the distal portion. The ratio between these two cross-sections, also referred to as the plunger ratio or piston-to-plunger ratio (where the proximal portion represents the "piston" and the distal portion the "plunger"), is greater than 1 in this embodiment, for example, between 5 and 50 or between 10 and 30. Therefore, the pressure acting on the proximal portion increases relative to the fluid pressure acting on the proximal portion. Therefore, during the release process, a sufficiently high fluid pressure can be generated in the pumping chamber to open the outlet valve (against the gas pressure in the ejector unit) without having to apply the same high pressure to the control chamber and control port.

[0025] The metering chamber may include an intermediate chamber in which the intermediate portion of the pumping plunger is disposed, and this intermediate chamber is connected to an inlet port via a bypass channel that bypasses an inlet valve or inflow opening. The intermediate portion is preferably positioned relative to the plunger axis between a proximal portion and a distal portion, although some overlap is conceivable. With the pumping plunger disposed within the metering chamber, fluid and pressure exchange between the intermediate chamber and the control chamber is prevented or at least impeded. However, the intermediate chamber is connected to the inlet port via the bypass channel. Therefore, regardless of the state of the inlet valve, the pressure in the intermediate chamber at least approximately corresponds to the pressure at the inlet port. This pressure acts on the intermediate portion of the pumping plunger and can generate a force acting in the proximal direction. Therefore, the pressure at the inlet port can be used to assist movement of the pumping plunger towards the proximal position.

[0026] One embodiment provides a lubricant supply system adapted to increase the fluid pressure at the inlet port and decrease the fluid pressure at the control port to introduce lubricant into the pumping chamber through the inlet port, and adapted to decrease the fluid pressure at the inlet port and increase the fluid pressure at the control port during the release process to eject the lubricant from the pumping chamber through the outlet port. Thus, two distinct processes and different stages can be distinguished. One stage, corresponding to the suction process, is used to introduce lubricant into the pumping chamber, which requires opening the inlet valve. If the inlet valve is a check valve, the pressure at the inlet port needs to be greater than the pressure in the pumping chamber. Therefore, increasing the pressure at the inlet port is meaningful. On the other hand, the pumping chamber should have its maximum volume, so the pumping plunger should be in its proximal position. Therefore, the pressure at the inlet port should be reduced. The other stage represents the release process, which requires the outlet valve to open and the pumping plunger to move to its distal position. During this process, the pressure at the control port should increase. Maintaining the pressure at the inlet port at a high level is conceivable, but this would increase the chance of opening the inlet valve during the release process. That is, during the release process, lubricant flows into the pumping chamber, making it impossible to control the release volume of the lubricant. Therefore, this embodiment provides a reduction in pressure at the inlet port for the release process. If an intermediate chamber communicating with the inlet port as described above exists, it can be understood that increased pressure at the inlet port helps move the pumping plunger to a proximal position, while decreased pressure at the inlet port helps move the plunger to a distal position.

[0027] Preferably, the lubricant supply system includes: a supply line connected to the inlet port of at least one lubricant metering device; and / or a control line connected to the control port of at least one lubricant metering device. The supply line can supply lubricant to at least one inlet port. It can be directly or indirectly connected to a lubricant reservoir. Specifically, the supply line can be connected to the lubricant reservoir via at least one valve and / or it can include at least one valve. The control line can supply fluid to the at least one control port. In particular, it can supply lubricant and can be at least indirectly connected to a lubricant reservoir, for example, the same lubricant reservoir as the supply line. The control line can be connected to the lubricant reservoir via at least one valve and / or it can include at least one valve.

[0028] While the supply or control lines can be connected to a single lubricant metering device, it is highly preferred that the supply line connect to multiple inlet ports and / or the control line connect to multiple control ports. One might say that the corresponding lines have a branched structure supplying multiple lubricant metering devices. Therefore, by controlling the pressure in the supply line, the pressure at the inlet ports of several lubricant metering devices can be controlled simultaneously. Similarly, by controlling the pressure in the control line, the pressure at the control ports of several lubricant metering devices can be controlled simultaneously. This greatly facilitates the synchronized operation of several (potentially all) lubricant metering devices. Synchronization is achieved "automatically" by subjecting all metering devices to the same pressure present in the supply or control lines.

[0029] Although the structure of the corresponding piping is referred to as a "branch," this refers to branch flow and does not mean that the piping includes branch lines. According to one embodiment, at least one lubricant metering unit includes a supply adapter port communicating with an inlet port, and at least one supply adapter line connects the supply adapter port of one lubricant metering unit to the inlet port of another lubricant metering unit. The supply adapter line can be considered as part of the supply piping system and / or part of the fuel rail assembly. Within the "first" lubricant metering unit, the inlet port communicates with a pumping chamber and also with the supply adapter port. Subsequent connections may bypass the pumping chamber. The supply adapter line connected to the supply adapter port of the first lubricant metering unit and the supply adapter line connected to the inlet port of the "second" lubricant metering unit then establishes a connection between the second lubricant metering unit and the supply piping. The second lubricant metering unit may also include a supply adapter port to which another supply adapter line may be connected, and so on. It should be understood that, using this design, the branch structure is effectively integrated into the lubricant metering unit. This allows for a more compact and / or more robust structure compared to the concept of branch lines. Preferably, each of the plurality of lubricant metering devices includes a supply adapter port, and the supply assembly and / or fuel rail assembly includes a plurality of supply adapter lines.

[0030] A similar concept can be used for control piping systems. According to another embodiment, at least one lubricant metering device includes a control adapter port communicating with a control port, and at least one control adapter line connects the control adapter port of one lubricant metering device to the control port of another lubricant metering device. The control adapter line can be considered part of a control piping system and / or a fuel rail assembly. Within a “first” lubricant metering device, a control port communicates with a control chamber and with the control adapter port. Subsequent connections can bypass the control chamber. A control adapter line connected to the control adapter port of the first lubricant metering device and connected to the inlet port of a “second” lubricant metering device then establishes a connection between the second lubricant metering device and the control piping system. The second lubricant metering device may also include a control adapter to which another control delivery line can be connected, and so on. Preferably, each of a plurality of lubricant metering devices includes a control adapter, and the control assembly and / or fuel rail assembly includes a plurality of control adapter lines.

[0031] Preferably, at least one supply transfer line and / or at least one control transfer line are airtightly and non-removably connected to at least one lubricant metering device. The corresponding connections can be established using joining techniques such as brazing, welding, or gluing. The inlet port, control port, supply transfer port, and / or control transfer port can be arranged on the aforementioned housing. For example, if the housing is brazed to the injector base, and at least one line is also brazed to the housing, all brazed connections can be achieved in a single operation. For instance, the individual components can be assembled together with brazing material and placed in an oven, where the elevated temperature melts the brazing material, and the components are joined.

[0032] The inlet port and supply adapter port can be aligned with each other. Therefore, they can be produced through a single drilling operation. This corresponds to a through-hole through the housing. Similarly, the control port and control adapter can be aligned with each other, so they can be produced through a single drilling operation. It is also preferred that all supply adapter lines are straight and aligned with each other. Likewise, it is preferred that all control adapter lines are straight and aligned with each other.

[0033] According to one embodiment, the lubricant supply system includes a high-pressure line connected to a lubricant reservoir and a low-pressure line connected to the lubricant reservoir, and is adapted to generate a higher pressure in the high-pressure line than in the low-pressure line. The lubricant reservoir may be a lubricant tank or the like. It may be open for pressure exchange with the surrounding atmosphere. Both the high-pressure and low-pressure lines are connected to the lubricant reservoir. However, during operation, the pressure in the high-pressure line increases. For this purpose, the high-pressure line may include a pressure pump. Preferably, the pressure in the low-pressure line corresponds to atmospheric pressure (i.e., about 1 bar), while the pressure in the high-pressure line can be considerably higher, for example, 5 to 20 times or 7 to 15 times higher.

[0034] Preferably, the lubricant supply system includes a valve assembly adapted to connect the supply line to a high-pressure line in a first state and to a low-pressure line in a second state. The valve assembly can be a single valve (e.g., a multi-way valve), but it can also include multiple valves. In the first state, which is available for the suction process, it connects the supply line to the high-pressure line, thereby increasing the pressure at the inlet port and allowing lubricant to flow into the pumping chamber while moving the pumping plunger to a proximal position. In the second stage, which is available for the release process, it connects the supply line to the low-pressure line, thereby reducing the pressure at the inlet port. If the inlet valve is a check valve, it will close due to the reduced pressure at the inlet port, thus maintaining a higher pressure inside the pumping chamber.

[0035] Preferably, the valve device is adapted to fluidly connect the control line to the low-pressure line in a first state and to fluidly connect the control line to the high-pressure line in a second state. In other words, in this embodiment, the valve device alternately connects the supply line and the control line to the high-pressure line (or the low-pressure line). Conversely, it alternately connects the high-pressure line and the low-pressure supply line to the control line (or the supply line). In the first state, the control line is connected to the low-pressure line, thus reducing the pressure at the control port, which helps move the pump plunger to a proximal position. In the second state, the control line is connected to the high-pressure line, thereby increasing the pressure at the control port, which helps move the pump plunger to a distal position, increasing the pressure in the pump chamber and opening the outlet valve (if it is a check valve). This embodiment enables pump plunger actuation by using the same lubricant used for lubricating fuel injectors. No additional fluid supply is required. Different processes—refilling and releasing—are initiated by changing the state of the valve device.

[0036] The present invention also provides a fuel rail assembly for a gas-fueled engine. The fuel rail assembly includes: - A fuel rail, used for transporting gaseous fuel. - The fuel rail is equipped with multiple injector mounts adapted to connect corresponding fuel injectors to the fuel rail, and - At least one lubricant metering device, the at least one lubricant metering device including an outlet port, each lubricant metering device being adapted to controllably release liquid lubricant into an injector base through the outlet port and being mounted to the injector base.

[0037] All these terms have been explained above with reference to the supply system of the present invention and will therefore not be explained again. Preferably, the fuel rail assembly includes a plurality of lubricant metering devices, i.e., one lubricant metering device per injector base. The lubricant metering device may specifically be the lubricant metering device disclosed herein. It should be understood that the fuel rail assembly of the present invention can be used in, and may be part of, the supply assembly of the present invention. Preferred embodiments of the fuel rail assembly of the present invention correspond to preferred embodiments of the supply assembly of the present invention. Specifically, the supply lines and / or control lines may be considered at least partially as part of the fuel rail assembly. This is particularly applicable to the supply transfer lines and / or control transfer lines described above. When the lubricant metering device is actuated to perform lubricant release, lubricant is released through the base toward the injector inlet port. In embodiments, the lubricant metering device outlet may, for example, be arranged to discharge lubricant directly into the base channel or indirectly through a dedicated channel.

[0038] Specific embodiments of the fuel rail assembly of the present invention are disclosed below.

[0039] In this embodiment, a corresponding lubricant metering device (31) is installed on each injector base; all lubricant metering devices are provided with lubricant inlet ports and are connected in a row via supply lines integrated into the fuel rail assembly (5).

[0040] In one embodiment, two adjacent lubricant metering units are connected via an integrated supply line that connects the inlet port of the subsequent lubricant metering unit to the supply adapter port of the preceding lubricant metering unit, wherein the supply adapter port communicates with the inlet port of the preceding lubricant metering unit. Specifically, the inlet port and supply adapter port of the respective lubricant metering unit may extend substantially tangentially through the housing of the lubricant metering unit.

[0041] In this embodiment, all lubricant metering units are provided with a control port. Two adjacent lubricant metering units are connected via an integrated control line that connects the control port of the subsequent lubricant metering unit to the control adapter port of the previous lubricant metering unit, wherein the control adapter port is in communication with the control port in the previous lubricant metering unit. In particular, the control port and control adapter port of the respective lubricant metering unit may extend substantially tangentially through the housing of the lubricant metering unit.

[0042] In one embodiment, the control line includes: a plurality of line segments connecting the supply advance port of a previous lubricant metering device to the inlet port of a subsequent lubricant metering device; and / or the supply line includes: a plurality of line segments connecting the control transition port of a previous lubricant metering device to the control port of a subsequent lubricant metering device.

[0043] In one embodiment, the metering device housing houses internal components including: a plunger body defining a pumping chamber and a metering device cavity; a valve seat portion connected to a distal end of the plunger portion to form a seat for an outlet valve; and a pumping plunger. An inlet port opens to an inlet chamber upstream of the pumping chamber, and a corresponding supply adapter port communicates with the inlet chamber. A control port opens to a control chamber on the proximal face of the pumping plunger, and a control adapter port communicates with the control chamber.

[0044] In one embodiment, the supply line is a single line connecting all the lubricant metering devices, the single line having a lateral opening at the level of each lubricant metering device except the last one in the flow direction, communicating with the inlet chamber; and / or the control line is a single line connecting all the lubricant metering devices, the single line having a lateral opening at the level of each lubricant metering device except the last one in the flow direction, communicating with the control chamber. Attached Figure Description

[0045] Preferred embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 This is a perspective view of the components of the supply assembly of the present invention having the fuel rail assembly of the present invention; Figure 2 It comes from Figure 1 A cross-sectional view of the lubricant metering device and injector unit of the supply components; Figure 3 yes Figure 2 A cross-sectional view of the lubricant metering device in the first state; Figure 4 yes Figure 2 A cross-sectional view of the lubricant metering device in the second state; Figure 5 It comes from Figure 1 A schematic diagram of the supply components and the engine; Figure 6 This is a cross-sectional view of the fuel rail assembly of the present invention, wherein another embodiment of the lubricant metering device is in a first state; Figure 7 yes Figure 6 A cross-sectional view of the fuel rail assembly, in which the lubricant metering device is in the second state; Figure 8 This is a perspective view of another fuel rail assembly of the present invention; Figure 9 yes Figure 8 Side view of the fuel rail assembly; Figure 10 From Figure 9 The view observed from the X-direction in the middle; Figure 11 It is along Figure 10 A cross-sectional view of plane XI-XI in the middle; Figure 12 It is along Figure 9 The cross-sectional view of plane XII-XII in the middle; and Figure 13 It corresponds to Figure 12 A cross-sectional view showing the lubricant metering device components removed; and Figure 14 It corresponds to Figure 13 The cross-sectional view shows another embodiment of the fuel rail assembly of the present invention. Detailed Implementation

[0046] Figure 1 A perspective view of the components of the supply assembly 1 of the present invention for a gas fuel engine 70 is shown, while Figure 5 This is a schematic diagram of the supply assembly 1 and the engine 70. The supply assembly 1 includes a fuel supply system 10, which is adapted to supply gaseous fuel, in this case hydrogen fuel, to the engine 70. The engine 70 only... Figure 5 The diagram is schematically shown. It includes multiple cylinders (not shown), each receiving fuel from fuel injectors 20 of the fuel supply system. In other words, there is one fuel injector 20 for each cylinder, totaling four in this case. Each fuel injector 20 is connected to the fuel rail 12 via an injector base 14, which is fixedly connected to the fuel rail 12. Specifically, each fuel injector 20 is connected to an injector interface 17, which can be considered part of the injector base 14. The fuel injectors 20 and the injector base 14 together form an injector unit 13. During operation of the engine 70, pressurized fuel (having a fuel pressure of, for example, 40 bar) is supplied to the fuel rail 12 via connecting lines 11 and from the fuel rail 12 to each injector unit 13. The precise operating principle of the fuel injectors 20 is not important and will not be described in detail. Figure 2As shown, the fuel injector 20 includes an injector body 21 that defines a fuel passage 22 extending from an inlet opening 23 to an outlet opening (not shown). The outlet opening can be closed by a needle valve that mates with a valve seat. The needle valve is movable by an armature that can be moved by an electric field generated by a magnetic coil. The inlet opening 23 communicates with a base passage 15 of the base 14. A base lubricant passage 16 branches from the base passage 15 and will be explained later.

[0047] The fuel rail 12 can be of a conventional design. It typically comprises a tubular body 12.1 that defines a filling chamber 12.2 in which fuel gas accumulates before flowing to the individual injectors. The fuel rail 12 has a gas supply port 12.3 through which gaseous fuel enters the filling chamber 12.2. In the illustrated embodiment, the supply port 12.3 is centrally located, thereby closing the tubular body 12.1 at both axial ends (particularly at one end) with plugs 13 having integrated pressure sensors 9.

[0048] Furthermore, the supply assembly 1 includes a lubricant supply system 30 adapted to supply liquid lubricant L to the fuel injector 20. In this case, it includes a total of four lubricant metering devices 31, each mounted on the injector base 14. Each lubricant metering device 31 may also be referred to as a volumetric metering device or a pumping metering device. It includes a metering device body 32 defining a metering device cavity 33. At least a portion of the metering device body 32 may be non-removably and sealably connected to the injector base 14, for example, by brazing. Within the metering device cavity 33, a pumping plunger 34 is movable along a plunger axis A. At the distal end face of the pumping plunger 34, there is a pumping chamber 35, which is part of the metering device cavity 33. The pumping chamber 35 communicates with an inlet port 36 via an inlet valve 37 and with an outlet port 38 via an outlet valve 39. The outlet port 38, in turn, communicates with the base lubricant passage 15. Therefore, the lubricant L released from the outlet port 37 can traverse the base lubricant channel 16 and the base channel 15 and enter the injector 20. The fuel rail 12, the injector base 14, and the lubricant metering device 31 are components of the fuel rail assembly 5 of the present invention.

[0049] Now refer to Figures 3 to 5 Explain the operation of the lubricant metering device 31. The pumping plunger 34 can move along the plunger axis A... Figure 3 The proximal position shown and Figure 4The movement between the distal positions shown. The volume of the pumping chamber 35, partially defined by the distal portion 33.1 of the pumping plunger 33, is larger at the proximal position than at the distal position. The movement of the pumping plunger 33 towards the distal position corresponds to a release process in which lubricant L is released through the outlet port 38, as shown. Figure 4 As shown. The lubricant L in the pumping chamber 35 is compressed, and the increased pressure opens the outlet valve 39, which is a check valve. On the other hand, the inlet valve 37, which is also a check valve, closes at this time due to overpressure in the pumping chamber 35 relative to the inlet port 36. This overpressure is partly due to a decrease in pressure at the inlet port 36. Figure 5 As shown, the inlet ports 36 of all lubricant metering devices 31 are connected to the supply line 45. The supply line 45 is connected to a valve assembly 47 (in this case, a multi-port valve), which in a first state connects the supply line 45 to the high-pressure line 49 and in a second state connects the supply line 45 to the low-pressure line 51 (in... Figure 5 (as shown in the diagram), while the low-pressure line 51 is directly connected to the lubricant reservoir 48, and the high-pressure line 49 is connected to the lubricant reservoir 48 via the pressure pump 50, which increases the lubricant pressure at the reservoir 48 from 1 bar to, for example, between 2 bar and 5 bar.

[0050] High-pressure line 49 and low-pressure line 51 are connected via safety valve 52 (which bypasses pressure pump 50). Control unit 75 controls the switching state of valve device 47. For the release process, supply line 45 is connected to low-pressure line 51. On the other hand, control line 46 is connected to high-pressure line 49. Control line 46 is connected to control port 42 of each lubricant metering device 31. Figure 3 and Figure 4As shown, control port 42 communicates with control chamber 41, which is located on the proximal end face of pump plunger 34 and partially defined by the proximal portion 34.3 of pump plunger 34. When control line 46 is connected to high-pressure line 49, the increased pressure acts on proximal portion 34.3. Simultaneously, the relatively low pressure of low-pressure line 51 acts on intermediate portion 34.2 of pump plunger 34, which is located in intermediate chamber 40 of metering chamber 33. This is because intermediate chamber 40 communicates with inlet port 36 via bypass passage 43 of bypass inlet valve 37. The force acting on intermediate portion 34.2 due to this pressure is much smaller than the force acting on proximal portion 34.3. Furthermore, although the pressure in pumping chamber 35 is as high as or even higher than the pressure in control chamber 41, the resulting force is much smaller because proximal portion 34.3 has a much larger cross-section perpendicular to plunger axis A than distal portion 34.1. Therefore, the pumping plunger 34 moves to the distal position, causing a release process, which is achieved simultaneously in all lubricant metering units 31. The pumping chamber 35 and the pumping plunger 34 are designed such that the pumping volume displaced by the pumping plunger between the proximal and distal positions is less than 20 mm. 3 Preferably less than 10mm 3 More preferably less than 5mm 3 The pumping volume is at least approximately the same as the defined release volume released from each lubricant metering device 34.

[0051] For the suction process, control unit 75 connects supply line 45 to high-pressure line 49 and control line 46 to low-pressure line 51. This causes an increase in pressure at inlet port 36 and in the intermediate chamber, while the pressure at the control port decreases. Consequently, pump plunger 34 moves to the proximal position. Furthermore, inlet valve 46 opens, allowing lubricant L to flow into pump chamber 35, which is now ready for another release process.

[0052] Regarding the inlet valve 37 and outlet valve 39, they can be designed as check valves, as previously noted. Typically, they include ball valve members 37.1, 39.1 that mate with a valve seat. The ball valve members are biased in the closed position by helical springs 37.2, 39.2. For the inlet valve, a coil is arranged around a stop pin 37.3. The stop pin 37.3 extends from a base member screwed into the body, thereby allowing adjustment of the distance between the pin end and the valve member in the closed position.

[0053] Regarding the outlet valve 39, the outlet valve is arranged in the outlet channel of the body 32. A ball 39.1 is arranged in a recess of a support member 39.3. This support member includes an annular shoulder against which one end of a coil spring 39.2 abuts. The other end of the coil spring rests on an annular shoulder of a fastener screwed into the outlet channel. Therefore, the ball 39.2 can move within the outlet channel. The ball can be made of an elastic plastic material (e.g., an elastomer), or it can be a metal ball coated with a plastic / elastomeric material. The ball 39.1 partially protrudes from its support member 39.3, and the edge of the recess is surrounded by an annular stop surface 39.4 that restricts the compression of the ball 39.

[0054] Figure 6 and Figure 7 The fuel rail assembly 5 of the present invention, shown in another embodiment, has a lubricant metering device 31 that can be used to replace... Figures 2 to 4 The embodiment shown is described only to the extent that it differs from the first embodiment. In this embodiment, the meter body 32 includes two external portions, namely a cup-shaped housing 53 and a housing cover 54, which together form the meter housing. The meter housing includes an internal assembly 55, which includes the internal portion of the meter body 32, for example, connected by a press fit. A plunger portion 56 defines the main portion of the pumping chamber 35 and the metering chamber 33. A valve seat portion 57 connected to the distal end of the plunger portion 56 forms the valve seat of the outlet valve 39. The internal assembly 55 also includes a pumping plunger 34. The internal assembly 55 can be pre-assembled before being placed into the housing 53. The housing cover 54 can then be assembled to the housing 53 and threadedly connected to it. Thus, the internal assembly 55 is encapsulated between the housing 53 and the housing cover 54. The housing cover 54 includes a plurality of ribs 54.1 that engage with the plunger portion 56 while leaving space between them for the control chamber 41. The housing cover 53 can be non-removably connected to the injector base 14 by brazing before the internal components 55 are placed inside the housing housing 53.

[0055] An elastomer O-ring 44 is circumferentially arranged around the pump plunger 34. It provides a reliable seal between the control chamber 41 and the intermediate chamber 40, while keeping the length of the pump plunger 34 and its stroke length (i.e., the distance between the proximal and distal positions) relatively small. This helps limit the overall size of the lubricant metering device 31.

[0056] Unlike the first embodiment, the lubricant metering device 31 does not include an inlet valve. Instead, the inlet port 36 communicates with the pumping chamber 35 via an inflow opening 59, which may be formed as a micropore. It is disposed adjacent to the pumping chamber 35. When the pumping plunger 34 is in the proximal position, as Figure 6 As shown, the inflow opening 59 is opened by the pumping plunger 34, allowing lubricant L to flow into the pumping chamber 35, as indicated by the arrow. When the pressure in the control chamber 41 increases, the pumping plunger 34 moves to a distal position and seals the inflow opening 59, thereby preventing lubricant L from escaping towards the inlet port 36. Instead, lubricant L is discharged through the outlet valve 39 and the outlet port 38. To facilitate lubricant distribution, a perforated outlet cap 58 is provided at the outlet port 38. It includes multiple through-holes through which lubricant L is released. These through-holes are too small to be shown in the figure. In this embodiment, the outlet cap 58 is a single metal body with multiple through-holes.

[0057] As described above, when the pressure at control port 42 decreases and the pressure at inlet port 36 decreases, the pumping plunger 34 moves toward the proximal position, eventually reopening the inflow opening 59, so that the pumping chamber 35 is once again fluidly connected to the inlet port 36. As in the previous embodiment, the bypass passage 43 is arranged such that the movement of the pumping plunger 34 into the proximal position can be facilitated by the lubricant pressure in the intermediate chamber 40, while the inflow opening 59 is blocked by the pumping plunger 34.

[0058] Figures 8 to 13 A second embodiment of the fuel rail assembly 5 of the present invention is shown. Similar to the first embodiment, it includes a fuel rail 12 and a total of four injector bases 14 each having an injector interface 17. A lubricant metering device 31 is mounted on each injector base 14. Figure 12 The design of the lubricant metering device 31, which can be seen in the cross-sectional view, is basically the same as... Figure 6 and 7 The illustrated embodiment is the same and will not be described further. The housing 53 is brazed to the injector base 14. In this embodiment, there is no dedicated inlet valve, but the inlet port communicates with the pumping chamber via the inflow opening 59. Figure 6 and 7 The embodiment is similar. However, similar to the first embodiment, the inlet port 36 also communicates with the intermediate chamber 40 via a bypass channel 43 through the bypass inflow opening 59. Another difference is that the inlet port 36 and the control port 42 do not traverse the housing 53 radially relative to the plunger axis A, but rather traverse the housing 53 tangentially. The inlet port 36 and the supply transition port 60 are formed by a single through-hole traversing the housing 53, while the control port 42 and the control transition port 61 are formed by another through-hole also traversing the housing 53. The location and diameter of the through-holes are chosen such that they intersect with the metering chamber 33, which allows for... Figure 11 As seen in the cross-sectional view.

[0059] One end of pipe section 62 to 65 (or simply pipe) is inserted into the through hole from either side. For example... Figure 11As shown, a portion of the through-hole at the ends of the corresponding conduits 62 to 65 may have a slightly larger diameter to define a stop surface. However, during assembly, the ends of the conduit segments preferably do not contact the stop surface to allow for thermal expansion (especially during brazing). Specifically, one end of the supply connection conduit 62 is connected to the first lubricant metering device 31. Figure 8 and Figure 9 The first lubricant metering unit 31 has its inlet port 36 (the leftmost port in the first lubricant metering unit 31) connected to the control port 42 of the first lubricant metering unit 31. A supply transfer line 63 connects to the supply transfer port 60 of the first lubricant metering unit 31, and a control transfer line 65 connects to the control transfer port 61 of the first lubricant metering unit 31. The supply transfer line 63 also connects to the inlet port 36 of the second lubricant metering unit 31, and the control transfer line 65 also connects to the control port 42 of the second lubricant metering unit 31. Connections to the third and fourth lubricant metering units 31 are established in a similar manner. However, the fourth lubricant metering unit 31 does not include a supply transfer port 60 or a control transfer port 61. Each of the lines 62 through 65 is brazed to the housing 53 of the corresponding lubricant metering unit 31. These brazed connections can be applied together with the connection between the housing 53 and the injector base 14. Brazing is typically performed to form a continuous metallurgical bond, thereby also providing an airtight connection.

[0060] exist Figure 14 In another embodiment shown, the housing 53 and the injector base 14 are made of a single piece of metal. This simplifies the assembly and brazing process of the fuel rail assembly 5.

[0061] like Figure 8 and Figure 9 As shown, all pipes 62 to 65 are straight and aligned with each other. They connect the different lubricant metering devices 31 one after another in a row. Therefore, it can be said that the lubricant metering devices 31 are connected in series. Pipe sections 62 to 65 are fixedly mounted on the fuel rail 12. Thus, pipes 62 and 63 form an integrated supply line, while pipes 64 and 65 form an integrated control line.

[0062] exist Figure 12 In the figure, one will notice the tubular body 12.1 of the fuel rail 12, whose inflation chamber 12.2 communicates with the base channel 15 of the base 14 (through a radial orifice in the body 12.1). A lubricant metering device 31 is mounted on the base 14 to inject lubricant directly into the base channel 15. Reference numeral 66 indicates a continuous annular brazed joint that connects the metering device housing 53 and the injector interface 17 to the injector base 14.

[0063] The injector interface 17 can be used for direct connection to the injector. Therefore, it defines a connection channel 17.1 that communicates with the base channel 15 and is adapted to receive the injector inlet portion (having its inlet opening).

[0064] In other embodiments not shown, the injector base 14 may include an outlet fitting located at the end of the base channel 14, through which the injector can be connected to the injector base via a conduit.

[0065] Still Figure 12 It is noted that the inlet port 36 opens in the inlet chamber 36.1 upstream of the pumping chamber, which is defined externally by the housing 53. Similarly, the control port 42 communicates with the control chamber 41. This is practically common to all embodiments, in which the subdivision within the housing 53 is achieved by a cylindrical portion (here, portion 56.1 of the plunger portion 56) that fits tightly within the housing 53. Preferably, the cylindrical portion 56.1 includes a peripheral groove 56.2 with an annular seal 56.3.

[0066] However, in this third embodiment, it can be noted that the supply adapter port 60 also communicates with the inlet chamber 36.1. Similarly, the control adapter port 61 also communicates with the control chamber 41. This is because these ports are tangentially drilled within the thickness of the outer shell wall, allowing them to communicate with the inner shell volume.

[0067] Legend of reference numbers:

Claims

1. A supply assembly (1) for a gas-fueled engine (70), the supply assembly comprising: - A fuel supply system (10) comprising a fuel rail (12) for supplying gaseous fuel and a plurality of injector units (13), each injector unit (13) comprising a fuel injector (20) at least indirectly connected to the fuel rail (12) and adapted to inject fuel into the engine (70), and - Lubricant supply system (30), the lubricant supply system including at least one lubricant metering device (31) having an outlet port (38), the lubricant metering device (31) being adapted to controllably release liquid lubricant (L) into the injector unit (13) through the outlet port (38), and the lubricant metering device being mounted to the injector unit (13).

2. The supply component according to claim 1, wherein, At least one injector unit (13) includes an injector base (14), through which the fuel injector (20) is connected to the fuel rail (12), and the lubricant metering device (31) is adapted to release lubricant (L) into the injector base (14) through the outlet port (38).

3. The supply component according to any one of the preceding claims, wherein, At least one lubricant metering device (31) is a volumetric metering device, the volumetric metering device comprising: a pumping chamber (35) communicating with the outlet port (38); and a pumping plunger (34) adapted to discharge lubricant (L) from the pumping chamber (35) so as to release lubricant (L) defining a release volume into the injector unit (13) during the release process.

4. The supply component according to any one of the preceding claims, wherein, The supply assembly is adapted to simultaneously initiate the release process in multiple lubricant metering devices (31).

5. The supply component according to any one of the preceding claims, wherein, The lubricant metering device (31) includes a metering body (32) having a metering cavity (33) in which the pumping plunger (34) is movable along a plunger axis (A) between a proximal position and a distal position, such that the volume of the pumping chamber (35), which is partially defined by the distal portion (34.1) of the pumping plunger (34), is larger at the proximal position than at the distal position, and the lubricant metering device (31) also includes an inlet port (36) communicating with the pumping chamber (35), and an outlet port (38) communicating with the pumping chamber (35) via an outlet valve (39).

6. The supply component according to any one of the preceding claims, wherein, The inlet port (36) is connected to the pumping chamber (35) via an inlet valve (37) or via an inflow opening (59), the inflow opening being disposed adjacent to the pumping chamber (35) such that the pumping plunger (34) blocks the inflow opening (59) at the distal end and opens the inflow opening (59) at the proximal end.

7. The supply component according to any one of the preceding claims, wherein, At least a portion of the metering body (32) is non-detachably connected to the injector base (14).

8. The supply component according to any one of the preceding claims, wherein, At least one of the inlet valve (37) and the outlet valve (39) is a check valve, the inlet valve (37) being adapted to open in response to overpressure at the inlet port (36) relative to the pumping chamber (35), and / or the outlet valve (39) being adapted to open in response to overpressure in the pumping chamber (35) relative to the outlet port (38).

9. The supply component according to any one of the preceding claims, wherein, The metering chamber (33) includes a control chamber (41) on the proximal face of the pumping plunger (34), the control chamber (41) being in communication with a control port (42), and the pumping plunger (34) being able to move to the distal position by fluid pressure at the control port (42).

10. The supply component according to any one of the preceding claims, wherein, The proximal portion (34.3) of the pumping plunger (34) located adjacent to the control chamber (41) has a larger cross-section perpendicular to the plunger axis (A) than the distal portion (34.1).

11. The supply component according to any one of the preceding claims, wherein, The metering chamber (33) includes an intermediate chamber (40), the middle portion (34.2) of the pumping plunger (34) is disposed in the intermediate chamber (40), and the intermediate chamber (40) is connected to the inlet port (36) through a bypass channel (43), which bypasses the inlet valve (37) or the inflow opening (59).

12. The supply component according to any one of the preceding claims, wherein, The lubricant supply system (30) is adapted to increase the fluid pressure at the inlet port (36) and decrease the fluid pressure at the control port (42) to introduce lubricant into the pumping chamber (35) through the inlet port (36), and is adapted to decrease the fluid pressure at the inlet port (36) and increase the fluid pressure at the control port (42) during the release process to spray lubricant from the pumping chamber (35) through the outlet port (38).

13. The supply component according to any one of the preceding claims, wherein, The lubricant supply system (30) includes: a supply line (45) connected to an inlet port (36) of at least one lubricant metering device (31); and / or a control line (46) connected to the control port (42) of at least one lubricant metering device (31).

14. The supply component according to any one of the preceding claims, wherein, At least one lubricant meter (31) includes a supply adapter port (60) communicating with the inlet port (36), and at least one supply adapter pipeline (63) connects the supply adapter port (60) of one lubricant meter (31) to the inlet port (36) of another lubricant meter (31).

15. The supply component according to any one of the preceding claims, wherein, At least one lubricant metering device (31) includes a control adapter port (61) communicating with the control port (42), and at least one control adapter line (65) connects the control adapter port (61) of one lubricant metering device (31) to the control port (42) of another lubricant metering device (31).

16. The supply component according to any one of the preceding claims, wherein, The supply line (45) is connected to multiple inlet ports (36), and / or the control line (46) is connected to multiple control ports (42).

17. The supply component according to any one of the preceding claims, wherein, The lubricant supply system (30) includes a high-pressure line (49) connected to a lubricant reservoir (48) and a low-pressure line (51) connected to the lubricant reservoir (48), and the lubricant supply system (30) is adapted to generate a higher pressure in the high-pressure line (49) than in the low-pressure line (51).

18. The supply component according to any one of the preceding claims, wherein, The lubricant supply system (30) includes a valve device (47) adapted to fluidly connect the supply line (45) to the high-pressure line (49) in a first state and to fluidly connect the supply line (45) to the low-pressure line (51) in a second state, wherein, preferably, the valve device (47) is adapted to fluidly connect the control line (46) to the low-pressure line (51) in the first state and to fluidly connect the control line (46) to the high-pressure line (49) in the second state.

19. A fuel rail assembly (5) for a gas-fueled engine (70), the fuel rail assembly comprising: - Fuel rail (12), the fuel rail being used to transport gaseous fuel. - The fuel rail (12) is provided with a plurality of injector bases (14) adapted to connect corresponding fuel injectors (20) to the fuel rail (12), and - At least one lubricant metering device (31), the at least one lubricant metering device including an outlet port (38), each lubricant metering device (31) being adapted to controllably release liquid lubricant (L) into the injector base (14) through the outlet port (38), and each lubricant metering device (31) being mounted to the injector base (14).

20. The fuel rail assembly (5) according to claim 19, wherein, The corresponding lubricant metering device (31) is installed on each injector base; All lubricant metering devices are provided with lubricant inlet ports and are connected in a row via supply lines integrated into the fuel rail assembly (5).

21. The fuel rail assembly (5) according to claim 20. in, Two adjacent lubricant metering devices are connected by an integrated supply line (63) that connects the inlet port (36) of the subsequent lubricant metering device to the supply adapter port (61) of the previous lubricant metering device, wherein the supply adapter port (61) is in communication with the inlet port (42) in the previous lubricant metering device.

22. The fuel rail assembly (5) according to claim 21, wherein, The inlet port (36) and the supply adapter port (61) of the corresponding lubricant meter (31) extend substantially tangentially through the housing (53) of the lubricant meter.

23. The fuel rail assembly (5) according to claim 20, 21 or 22, wherein, All lubricant dispensers are equipped with control ports. Two adjacent lubricant metering devices are connected by an integrated control line that connects the control port (42) of the subsequent lubricant metering device to the control adapter port (61) of the previous lubricant metering device, wherein the control adapter port (61) is in communication with the control port (42) in the previous lubricant metering device.

24. The fuel rail assembly (5) according to claim 23, wherein, The control port and the control adapter port (61) of the corresponding lubricant meter extend substantially tangentially through the housing of the lubricant meter.

25. The fuel rail assembly (5) according to any one of claims 20 to 24, wherein, The control piping includes multiple piping segments that connect the supply adapter port (36) of the previous lubricant metering device to the inlet port (36) of the subsequent lubricant metering device; and / or The supply line includes multiple line segments that connect the control adapter port (61) of the previous lubricant metering device to the control port (42) of the subsequent lubricant metering device.

26. The fuel rail assembly (5) according to any one of claims 19 to 25, wherein, The metering device housing houses internal components, including: a plunger body defining the pumping chamber 35 and the metering device cavity 33; a valve seat portion 57 connected to the distal end of the plunger portion 56 to form a valve seat for the outlet valve 39; and a pumping plunger 34. The inlet port (36) leads to the inlet chamber (36.1) upstream of the pumping chamber, and the corresponding supply transfer port (60) communicates with the inlet chamber; The control port (42) leads to the control chamber (41) on the proximal end face of the pumping plunger, and the control adapter port (61) communicates with the control chamber.

27. The fuel rail assembly (5) according to claim 26, wherein, The supply line is a single line connecting all the lubricant metering devices, and the single line has a lateral opening at the level of each lubricant metering device except for the last lubricant metering device in the flow direction, communicating with the inlet chamber; and / or The control line is a single line connecting all the lubricant metering devices, and the single line has a lateral opening at the level of each lubricant metering device except for the last lubricant metering device in the flow direction, communicating with the control chamber.

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