High-pressure-differential methanol injector for marine engine, and injection valve suitable for multiple fuels

Abstract

A high-pressure-differential methanol injector for a marine engine, the methanol injector comprising a gland (1), a solenoid valve (4), a housing (6), a push rod (7), a spring (8), a stroke-limiting disk (9), a valve body (10), a valve core bushing (12), an injection hole plate (11), and a valve seat (13), wherein the gland (1), the housing (6) and the valve core bushing (12) are detachably connected to one another from top to bottom and form a press-fitting cavity having a lower opening; in the press-fitting cavity, the injection hole plate (11) is arranged at the opening of the valve core bushing (12), the valve seat (13) is arranged above the injection hole plate (11), the stroke-limiting disk (9) is arranged above the valve seat (13), the spring (8) is limited between the push rod (7) and the stroke-limiting disk (9), the lower end of the push rod (7) passes through the stroke-limiting disk (9) and is then connected to the valve body (10) in the valve seat (13), the upper end of the push rod (7) is connected to the solenoid valve (4), and a pressure accumulation cavity is formed between the valve body (10) and the valve seat (13); and under the combined action of the electromagnetic force provided by the solenoid valve (4) and the methanol supply pressure in the pressure accumulation cavity, the valve body (10) moves together with the push rod (7), such that a gap is formed between the valve body (10) and the valve seat (13), and methanol fuel in the pressure accumulation cavity passes through the gap and is then sprayed outwards from injection holes of the injection hole plate (11). The methanol supply pressure is used to assist in opening the valve core of the methanol injector. Compared with a conventional injector in which a direct-drive solenoid valve opens a valve core, the structure requires only a smaller electromagnetic force and lower power consumption to open the methanol injector. Moreover, by accurately matching the spring (8) with the supply pressure, a higher methanol injection pressure can be provided, and more efficient atomization can be realized.

Description

A high-pressure differential methanol injector for marine engines and an injection valve suitable for various fuels.

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202510471469.1, filed on April 15, 2025, entitled "A High-Pressure Differential Methanol Injector for a Marine Engine", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the technical field of methanol fuel injection systems for marine engines, specifically a high-pressure differential methanol injector for marine engines and an injection valve suitable for various fuels. Background Technology

[0004] As is well known, carbon reduction in shipping plays a crucial role in addressing global warming. The application of low-carbon and zero-carbon alternative energy sources is a vital path to green shipping, and methanol is widely recognized as a significant alternative fuel. In recent years, with the increasing prominence of the near-zero carbon emissions of green methanol, the demand for methanol-powered ships has surged, and methanol engines have become a "new favorite" in the shipbuilding market. The methanol intake injection technology, in particular, is favored by major engine manufacturers and shipowners due to its ability to be directly retrofitted to existing diesel engines, its short development cycle, low cost, and excellent adaptability.

[0005] As a key component of marine engine fuel injection systems, the intake manifold methanol injector efficiently injects methanol fuel into the intake manifold, where it mixes with air and is then supplied to the engine cylinders for complete combustion, thus enabling the engine to continuously output power. Currently, there are relatively few methanol fuel injectors on the market specifically designed for high-power marine engines, and those that exist often suffer from poor atomization and inconvenient maintenance due to their high integration. Therefore, developing a methanol injector specifically designed for high-power marine methanol engines with excellent atomization and easy maintenance is crucial for both the market application of methanol fuel engines and the successful achievement of emission reduction goals in the entire shipping industry.

[0006] Public content

[0007] This application provides a high-pressure differential methanol injector for marine engines, which efficiently atomizes methanol by increasing the injection pressure, and features good atomization effect, high reliability, and convenient maintenance.

[0008] The technical solution of this application is as follows:

[0009] A high-pressure differential methanol injector for a marine engine includes: a gland, a solenoid valve assembly, a housing, a push rod, a spring, a limit disc, a valve body, a valve core bushing, a nozzle plate, and a valve seat;

[0010] The gland, housing, and valve core bushing are detachably connected from top to bottom to form a press-fit cavity with an opening at the bottom;

[0011] Inside the press-fitting chamber, the nozzle plate is positioned at the opening of the valve core bushing, the valve seat is positioned above the nozzle plate, the limit plate is positioned above the valve seat, the spring is limited between the push rod and the limit plate, the lower end of the push rod passes through the limit plate and connects to the valve body inside the valve seat, the upper end of the push rod is connected to the solenoid valve assembly, and a pressure accumulator is formed between the valve body and the valve seat.

[0012] The housing is provided with a fuel inlet. After methanol fuel enters the housing through the fuel inlet, it passes through the valve seat and enters the accumulator chamber formed between the valve seat and the valve body.

[0013] Under the combined action of the electromagnetic force provided by the solenoid valve assembly and the methanol supply pressure in the accumulator chamber, the valve body moves together with the push rod, creating a gap between the valve body and the valve seat. The methanol fuel in the accumulator chamber passes through this gap and is ejected outward from each nozzle of the nozzle plate.

[0014] Optionally, the high-pressure differential methanol injector for the marine engine further includes:

[0015] A limiting seat is provided at the top of the push rod. The electromagnetic force exerted by the solenoid valve assembly on the push rod can be adjusted by adjusting the height of the limiting seat.

[0016] Optionally, the solenoid valve assembly includes: an armature, a solenoid valve, and a yoke arranged sequentially from top to bottom;

[0017] The upper end of the push rod passes through the yoke and the solenoid valve and is then fixed to the armature.

[0018] Optionally, a boss is provided at the upper end of the armature, and the outer circle of the boss is clearance-fitted with the inner hole;

[0019] Multiple balance holes are evenly arranged along the axial direction between the upper and lower end faces of the armature.

[0020] Optionally, the solenoid valve includes: an explosion-proof plug, a solenoid coil, a frame, a stainless steel thin-walled sleeve, and an iron core;

[0021] A thin-walled stainless steel sleeve is wrapped around the outer surface of the skeleton that is in direct contact with methanol fuel;

[0022] The yoke is attached to the bottom end of the iron core.

[0023] Optionally, the push rod is provided with an outer circular boss, and a spring is connected between the limit plate and the outer circular boss, and the spring is sleeved on the push rod.

[0024] Optionally, the limit plate is provided with an oblong guide hole, and the valve seat is provided with a circular guide hole, with the circular guide hole and the oblong guide hole being coaxially arranged.

[0025] Optionally, the nozzle plate is a thin plate of uniform thickness of 0.8 to 1.2 mm, and the nozzle plate is drilled with multiple micro-holes with a diameter of 0.6 to 0.8 mm;

[0026] An angle is left between the micro-holes during processing, which allows methanol fuel to be injected circumferentially and / or unidirectionally.

[0027] Optionally, the lower end of the housing extends into the interior of the valve core bushing and is threaded.

[0028] The gland is pressed onto the upper end of the housing and screwed to the housing with screws.

[0029] Optionally, the valve body and valve seat are sealed to the methanol fuel in the accumulator chamber through line contact.

[0030] Optionally, a filter screen with different filter diameters is welded at the methanol fuel inlet.

[0031] This application embodiment also provides an injection valve suitable for multiple fuels, including a housing, a solenoid valve assembly, an orifice plate, a push rod, a valve stem, and a valve seat;

[0032] The housing, the valve seat, and the nozzle plate are connected in sequence;

[0033] The solenoid valve assembly, the push rod, and the valve stem are sequentially assembled within the space enclosed by the housing, the valve seat, and the nozzle plate.

[0034] The solenoid valve assembly includes: an iron core with a wire lead-out hole on one side of its lower end; an armature arranged above the iron core; a frame and a coil wound on it, the frame and coil being assembled between the main magnetic pole and the auxiliary magnetic pole of the iron core, and the upper end face of the frame being lower than the upper end face of the iron core to form a height difference; and an isolating plate fixed in the annular groove between the main and auxiliary magnetic poles of the iron core, covering the frame and the coil, the thickness of which matches the height difference.

[0035] One end of the push rod passes through the iron core and is connected to the armature, and the other end is connected to the valve stem;

[0036] The valve stem is movably arranged within the valve seat;

[0037] Fuel enters from the top of the upper housing, flows downward through the armature, the iron core, and the lower housing, and then enters the valve seat. Driven by the top rod, the valve stem forms a sealed state with the valve seat, either preventing fuel from being injected outward through the nozzle plate, or an open state, allowing fuel to be injected outward through the nozzle plate.

[0038] Optionally, the injection valve suitable for multiple fuels further includes a valve core bushing, and the housing includes a gland and a housing, wherein the gland, the housing and the valve core bushing are detachably connected from top to bottom to form a press-fit cavity with a lower opening;

[0039] Within the press-fitting cavity, the nozzle plate is disposed at the opening of the valve core bushing, and the valve seat is disposed above the nozzle plate; the solenoid valve assembly, the push rod, and the valve stem are sequentially assembled within the press-fitting cavity;

[0040] The casing is provided with a fuel inlet.

[0041] Optionally, the housing includes an upper housing and a lower housing, the upper housing, the lower housing, the valve seat and the nozzle plate being connected in sequence; the solenoid valve assembly, the push rod and the valve stem are sequentially assembled within the space enclosed by the upper housing, the lower housing, the valve seat and the nozzle plate.

[0042] Optionally, a first guide cylinder is installed in the central hole of the iron core for the push rod to pass through. The first guide cylinder is configured to constrain the circumferential position of the push rod and guide the movement of the push rod.

[0043] The interior of the first guide cylinder is coated with a self-lubricating coating.

[0044] Optionally, the armature is provided with a first fuel passage, the iron core and the push rod form a second fuel passage, the lower housing and the push rod form a third fuel passage, the lower housing and the valve seat form a fourth fuel passage, and the valve seat and the valve stem form a fifth fuel passage;

[0045] The outer wall of the valve seat is provided with a through hole communicating with its internal channel;

[0046] After the solenoid valve is energized, fuel enters from the upper housing, passes through the first fuel channel, the second fuel channel, the third fuel channel, the fourth fuel channel and the through hole in sequence, enters the fifth fuel channel, passes through the fuel flow gap formed between the valve seat and the valve stem, and finally flows to the nozzle plate and is sprayed outward.

[0047] The valve stem is coated with a self-lubricating plating.

[0048] Optionally, the interior of the upper housing is formed with a first central hole, a second central hole, a third central hole, and a fourth central hole that are sequentially connected and have progressively larger diameters;

[0049] The armature is assembled in the third central hole and has a distance between it and the stepped surface of the third central hole, so as to realize the reciprocating motion of the armature;

[0050] The iron core is assembled inside the fourth central hole;

[0051] A stabilizing spring is installed inside the second central hole. The stabilizing spring is configured to limit the static distance between the armature and the iron core of the solenoid valve assembly when the power is off.

[0052] Optionally, an upper mounting groove is provided on the stepped surface of the second central hole, and a lower mounting groove is provided on the upper end surface of the armature, with the stabilizing spring installed between the upper mounting groove and the lower mounting groove.

[0053] Optionally, a first oblique hole is provided between the first central hole and the second central hole, and a limiting oblique surface for radially limiting the stabilizing spring is formed on the wall of the second central hole.

[0054] Optionally, a return spring is connected between the valve seat and the push rod.

[0055] Optionally, the valve seat includes a first shaft segment and a second shaft segment connected in sequence;

[0056] The first shaft section extends into the upper housing, and the inner hole of the first shaft section serves as a guide cylinder for the valve stem;

[0057] The through hole is provided on the second shaft segment;

[0058] The shoulder of the second shaft section is fitted with the bottom stepped hole of the lower housing with a clearance.

[0059] Optionally, the upper ends of the upper housing and the lower housing are fixed together by a lower housing fastener screw.

[0060] The upper end of the valve seat extends into the lower end of the lower housing and is fixed to the lower housing by a valve seat cap screw.

[0061] The valve seat and the nozzle plate are fixed together by a nozzle plate fastener screw.

[0062] Optionally, the valve stem is threadedly connected to the push rod, and a first adjusting shim is provided between the upper end face of the valve stem and the threaded hole of the push rod; the armature is threadedly connected to the push rod, and a second adjusting shim is provided between the armature and the threaded hole of the push rod.

[0063] The advantages of the high-pressure differential methanol injector for marine engines provided in this application embodiment are as follows:

[0064] Under normal circumstances, the valve body is pushed downward by the methanol supply pressure, but this force is balanced by the upward force of the spring, keeping the valve body closed. When the solenoid valve assembly is energized, the electromagnetic force acts downward on the valve body through the push rod. At this time, the electromagnetic force only needs to overcome the spring force, and does not need to directly resist the methanol supply pressure. The methanol supply pressure actually helps the electromagnetic force to complete the valve opening action to a certain extent. Since the electromagnetic force only needs to overcome the spring force and does not need to directly resist the methanol pressure, less electromagnetic force and less power are required when the methanol injector needs to be opened. The methanol fuel entering the accumulator chamber is compressed when the valve body is closed, and the pressure gradually increases. After precise adjustment by the spring and the methanol supply pressure, a higher methanol injection pressure can be achieved. A higher injection pressure means that the methanol fuel flows faster at the nozzle plate. According to the principles of fluid mechanics, the higher the flow rate, the better the fuel atomization effect. Therefore, the high-speed injected methanol fuel is torn into finer droplets at the nozzle, thus achieving more efficient atomization.

[0065] The beneficial effects of the injection valve applicable to various fuels provided in the embodiments of this application include, for example:

[0066] By completely physically isolating the coil, frame, wires, and fuel through the isolation plate, the corrosion problem of methanol, ammonia, or hydrogen on the injection molding material of the solenoid valve is ideally solved, thus improving the service life of the injection valve. Attached Figure Description

[0067] Figure 1 is a schematic diagram of the high-pressure differential methanol injector according to an embodiment of this application;

[0068] Figure 2 is a schematic diagram of the armature, push rod and valve body in the embodiment of this application;

[0069] Figure 3 is a schematic diagram of the limit disk in an embodiment of this application;

[0070] Figure 4 is a schematic diagram of the valve core bushing in an embodiment of this application;

[0071] Figure 5 is a schematic diagram of the valve seat structure in an embodiment of this application;

[0072] Figure 6 is a cross-sectional view of the overall structure of the injection valve applicable to various fuels provided in the embodiment of this application;

[0073] Figure 7 is a cross-sectional view after rotating the view in Figure 6 by 90° along the axial direction;

[0074] Figure 8 is a partially enlarged structural view of Figure 7;

[0075] Figure 9 is an enlarged structural view of point B in Figure 7;

[0076] Figure 10 is an enlarged structural view of point A in Figure 7;

[0077] Figure 11 is a structural diagram of the valve core in this embodiment;

[0078] Figure 12 is a cross-sectional view of Figure 6 after rotating the view direction 45° along the axis;

[0079] Figure 13 is a structural diagram of the upper shell in this embodiment;

[0080] Figure 14 is a structural diagram of the lower housing in this embodiment.

[0081] Explanation of reference numerals in the attached figures:

[0082] The labels in Figures 1-5 are: 1-Gland; 2-Limit seat; 3-Armature; 31-Exhaust port; 32-Boss; 4-Solenoid valve; 5-Yoke; 6-Housing; 7-Push rod; 71-Side flat; 72-Outer circular boss; 8-Spring; 9-Limit plate; 91-Lower spring seat; 92-Oval guide hole; 10-Valve body; 11-Spray plate; 12-Valve core bushing; 121-Third shaft section inner hole; 122-Thread; 123-Side flat; 13-Valve seat; 131-Circular guide hole; 132-Valve seat sealing surface; 133-Guide hole; 101-Side flat; 102-Valve body sealing surface; 14-O-ring seal; 15-O-ring seal; 16-O-ring seal; 17-O-ring seal; 18-O-ring seal; 19-Hex socket head cap screw; 20-Hex socket head cap screw;

[0083] The labels in Figures 6-14 are as follows: 1-Upper housing; 2-Solenoid valve assembly; 3-Lower housing; 4-Orifice plate; 5-Push rod; 6-Valve stem; 7-Valve seat; 8-Lower housing fastener; 9-Valve seat fastener; 10-Orifice plate fastener; 11-Pressure block; 12-Stabilizing spring; 13-Return spring; 14-Spring seat; 15-First cylindrical pin; 16-Second cylindrical pin; 17-First adjusting pad; 18-Second adjusting pad; 101-First central hole; 102-First oblique hole; 103-Second central hole; 104-Third central hole; 105-Fourth central hole; 1051-Fifth O-ring seal; 106-First threaded hole; 107-Filter screen; 108-Sixth O-ring seal; 201-Core; 2011-Wire lead-out hole; 2012-Center hole; 202-Armature; 2021-First fuel passage; 2022-Lower mounting groove; 203-Frame; 204-Coil; 205-Isolating plate; 206-First guide cylinder; 207-Wire; 301-First O-ring seal; 302-Second O-ring seal; 303-Third O-ring seal; 304-Fourth O-ring seal; 305-Bottom surface; 401-Spray hole; 402-Sealing gasket; 501-Lower end face; 502-Second threaded hole; 503-First limiting post; 601-First sealing cone surface; 701 - Through hole; 702 - Fuel flow gap; 703 - Outer cylindrical surface; 704 - Second sealing cone surface; 705 - Upper end face; 707 - Seventh sealing ring; 708 - Eighth sealing ring; 709 - Upper end face. Detailed Implementation

[0084] To facilitate understanding by those skilled in the art, the present application patent is further described below with reference to the accompanying drawings. While the description is quite detailed, it should not be construed as limiting the scope of the present application patent. Obvious variations and substitutions of the following examples are all within the scope of protection of this patent.

[0085] This application provides a high-pressure differential methanol injector for marine engines.

[0086] "High pressure differential" mainly refers to the difference between the methanol fuel pressure inside the accumulator chamber and the external environmental pressure of the nozzle plate. The high pressure differential allows the methanol fuel to be ejected through the nozzle plate at a higher speed, thus achieving more efficient injection; the high pressure differential also allows the methanol fuel to be torn into smaller droplets when ejected, thus achieving more efficient atomization and improving combustion efficiency.

[0087] Referring to Figure 1, the high-pressure differential methanol injector includes: a pressure cap 1, a solenoid valve assembly, a housing 6, a push rod 7, a spring 8, a limit disc 9, a valve body 10, a valve core bushing 12, a nozzle plate 11, and a valve seat 13.

[0088] Referring to Figure 1, the gland 1, housing 6, and valve core bushing 12 are detachably connected from top to bottom to form a press-fit cavity with an open bottom. The gland 1 has a closed upper section, the housing 6 has a central hole, and the valve core bushing 12 has a U-shaped design with its lower opening for methanol fuel injection. The press-fit cavity formed inside the gland 1, housing 6, and valve core bushing 12 is configured to accommodate the installation of other components. The detachable connection of the gland 1, housing 6, and valve core bushing 12 makes maintenance and component replacement of the methanol injector more convenient. When repairs are needed on components within the press-fit cavity, the gland can be removed to replace or repair internal parts.

[0089] The solenoid valve assembly is pressed against the upper end face of the housing 1 by a pressure cap. The pressure cap 1 and the housing 6 are connected and fixed by four hexagon socket head cap screws 19. The pressure cap 1 has a first countersunk hole and a second countersunk hole from bottom to top, and there are four flow channels between the first countersunk hole and the second countersunk hole. The pressure cap 1 has four evenly distributed countersunk holes. The pressure cap is fixed to the housing 6 by passing the four hexagon socket head cap screws 19 through the countersunk holes. The bottom end of the pressure cap 1 has a groove for installing an O-ring seal 18. The O-ring seal 18 and the upper end face of the solenoid valve assembly form a first inner cavity seal.

[0090] Referring to Figure 1, in the press-fitting cavity, the nozzle plate 11 is located at the opening of the valve core bushing 12, the valve seat 13 is located above the nozzle plate 11, the limit plate 9 is located above the valve seat 13, the spring 8 is limited between the push rod 7 and the limit plate 9, the lower end of the push rod 7 passes through the limit plate 9 and connects to the valve body 10 in the valve seat 13, and the upper end of the push rod 7 is connected to the solenoid valve assembly; the housing 6 is provided with a fuel inlet, and the methanol fuel enters the housing 6 from the fuel inlet, and then passes through the valve seat 13 into the accumulator cavity formed between the valve seat 13 and the valve body 10.

[0091] The valve body 10 is fixed to the lower end of the push rod 7 by a threaded connection machined by the part itself.

[0092] The nozzle plate 11 is a thin plate of uniform thickness of 0.8 to 1.2 mm, on which multiple micro-holes with a diameter of 0.6 to 0.8 mm are drilled. An included angle is left between each micro-hole during processing. Micro-hole drilling or electrical discharge machining is used. The included angle includes, but is not limited to, circumferential spraying and unidirectional spraying.

[0093] The internal parts of the methanol injector are designed to be modular, allowing for disassembly, assembly, repair, and maintenance without damaging any parts. This improves the injector's assemblability and reduces subsequent maintenance costs.

[0094] The first shaft section of the housing 6, from bottom to top, is provided with external threads, which engage with the internal threads of the second shaft section of the valve core bushing 12 for a fixing function; and the first shaft section of the housing is sealed between the O-ring seal 14 and the valve core bushing 12. The upper end of the first shaft section of the housing has O-ring seals 15 and 16 respectively, and four waist-shaped through holes evenly distributed between the O-ring seals 15 and 16 are methanol fuel inlets.

[0095] This methanol injector features an insert-type installation design, allowing for easy removal of the entire injector during maintenance simply by unloading the pressure plate. This design offers convenient assembly and disassembly, along with high sealing reliability. Furthermore, the insert-type installation design avoids leaks that can occur with conventional top-mounted fuel systems due to insufficient coaxiality of external pipe connections, ensuring that the seal remains unaffected even under continuous engine vibration.

[0096] A double-layer filter screen is welded at the methanol fuel inlet, with an outer fine filter screen and an inner coarse filter screen to effectively filter the methanol fuel entering the injector.

[0097] The outer diameter of the second shaft section of the housing 6 from bottom to top is larger than the outer diameter of the first shaft section, and the inner hole of the second shaft section of the housing 6 is mainly configured to house the solenoid valve assembly.

[0098] The lower part of the outer circle of the second shaft section of the housing 6 has a groove, which is configured to place a fixing plate so that the methanol injector is fixedly installed on the engine intake manifold.

[0099] Under the combined action of the electromagnetic force provided by the solenoid valve assembly and the methanol supply pressure in the accumulator chamber, the valve body 10 moves together with the push rod 7, forming a gap between the valve body 10 and the valve seat 13. The methanol fuel in the accumulator chamber passes through this gap and is ejected outward from each nozzle of the nozzle plate 11.

[0100] Due to the balance mechanism between the spring and the methanol supply pressure, the electromagnetic force required for the solenoid valve assembly is significantly reduced. This means that the solenoid valve assembly consumes less electrical energy during operation, thereby reducing the overall energy consumption of the injection system. In the long-term operation of marine engines, this low-energy design can significantly reduce operating costs, especially in large-scale applications where the energy-saving effect is particularly pronounced. Furthermore, the reduced energy consumption also helps extend the lifespan of the injectors. The efficient atomization effect allows for more complete combustion of methanol fuel, reducing emissions of incompletely burned fuel. This not only improves combustion efficiency but also significantly reduces emissions of harmful gases such as carbon monoxide and hydrocarbons.

[0101] As shown in Figure 1, the high-pressure differential methanol injector for marine engines also includes:

[0102] The limiting seat 2 is disposed at the top of the push rod 7. The electromagnetic force exerted by the solenoid valve assembly on the push rod 7 can be adjusted by adjusting the height of the limiting seat 2.

[0103] As shown in Figure 1, the solenoid valve assembly includes, from top to bottom, an armature 3, a solenoid valve 4, and a yoke 5;

[0104] The upper end of the push rod 7 passes through the yoke 5 and the solenoid valve 4 and is then fixed to the armature 3.

[0105] As shown in Figure 2, the armature 3 and the limit seat 2 are connected to the upper end of the push rod 7 by the internal hexagonal head screw 20. The armature 3, the push rod 7 and the valve body 10 are a whole.

[0106] The yoke 3 is located at the bottom of the solenoid valve 4. The diameter of its outer circle and inner hole is close to that of the iron core of the solenoid valve 4. It is configured to increase the magnetic circuit of the solenoid coil of the solenoid valve assembly, thereby improving the utilization rate of electromagnetic force.

[0107] The solenoid valve 4 includes: an explosion-proof plug, a solenoid coil, a frame, a stainless steel thin-walled sleeve, and an iron core. The stainless steel thin-walled sleeve wraps around the outer surface of the frame, which is in direct contact with methanol fuel, to physically isolate methanol from the frame and prevent corrosion. The yoke 5 is attached to the bottom end of the iron core. An O-ring 17 seals the lower end of the iron core with the housing 6. The iron core is placed inside the frame's inner hole and has an interference fit with the stainless steel thin-walled sleeve. The upper end face of the iron core is higher than the outer surface of the stainless steel thin-walled sleeve at the upper end of the frame. There is a large gap between the inner hole of the iron core and the push rod 7, so they do not come into contact during the operation of the methanol injector. The upper and lower end faces of the frame are pressed together by sealing rings installed in the pressure cap 1 and the housing 6 to form a seal. The plug is located on one side of the housing 6.

[0108] This solution encapsulates the frame, electromagnetic coil, and connector into a single component, which is then press-fitted into the housing 6 using a cap 1. When the product malfunctions, it can be disassembled for repair and maintenance of the parts without replacing the entire methanol injector. This greatly improves the assemblability of the methanol injector and reduces subsequent maintenance costs.

[0109] When the methanol injector is in the open state, the gap between the armature 3 and the iron core of the solenoid valve 4 is an air gap. The air gap between the armature 3 and the iron core is adjusted by grinding the thickness of the limit seat 2.

[0110] As shown in Figure 2, the upper end of the armature 3 has a boss 32, and the bottom of the pressure cover 1 has an inner hole. The outer circle of the boss 32 and the inner hole of the pressure cover 1 are in clearance fit, which serves as a guide at the upper end. Four vent holes 31 are evenly distributed along the axial direction of the armature 3, which are configured to balance the pressure between the upper and lower end faces of the armature 3.

[0111] Currently, China's "carbon peaking" target is at a critical stage, and controlling emissions of greenhouse gases such as hydrocarbons and carbon oxides is urgently needed. In the shipping industry, methanol, ammonia, or hydrogen are widely recognized as important alternative fuels, playing a crucial role in the transition of marine engines from traditional diesel engine technology to dual-fuel engine technology. In recent years, technologies such as port-injected methanol, ammonia, or hydrogen have gained favor from major engine manufacturers and shipowners due to their flexibility, including direct modification of existing diesel engines, short development cycles, and low costs.

[0112] As a key actuator in the fuel injection system of marine dual-fuel engines, the intake manifold fuel injection valve effectively injects methanol, ammonia, or hydrogen into the engine intake manifold, where it mixes thoroughly with air before entering the cylinder for combustion. This significantly reduces greenhouse gas emissions such as hydrocarbons and carbon oxides while ensuring the engine can deliver the required power output.

[0113] Currently, the fuel application range of intake manifold injection valves in dual-fuel engines is relatively limited. For example, the injection valve in a modified methanol-diesel dual-fuel engine intake manifold injection system can only be used with methanol fuel. If the same engine is to burn ammonia or hydrogen fuel, a separate intake manifold fuel injection valve is required, which results in high modification costs and long construction periods. Therefore, this application seeks to develop an intake manifold fuel injection valve that can be used with methanol, ammonia, or hydrogen, aiming to improve the applicability of the intake manifold fuel injection system while meeting functional and reliability requirements.

[0114] This application provides an injection valve installed at the intake manifold of a marine engine and applicable to various fuels, comprising: a housing solenoid valve assembly 2, a lower housing 3, an orifice plate 4, a push rod 5, a valve stem 6, and a valve seat 7. The housing, the valve seat 7, and the orifice plate 4 are connected in sequence; the solenoid valve assembly 2, the push rod 5, and the valve stem 6 are sequentially assembled within the space enclosed by the upper housing 1, the lower housing 3, the valve seat 7, and the orifice plate 4; the solenoid valve assembly 2 includes: an iron core 201 with a wire lead-out hole 2011 on one side of its lower end; an armature 202 arranged above the iron core 201; a frame 203 and a coil 204 wound on it, the frame 203 and the coil 204 being assembled between the main magnetic pole and the auxiliary magnetic pole of the iron core 201, with the upper end surface of the frame 203 being lower than the upper end surface of the iron core 201 to form a height difference; and a separator 205 fixed to the iron core 201. The core 201 is located in the annular groove between the main and auxiliary magnetic poles, and covers the skeleton 203 and the coil 204. Its thickness matches the height difference. One end of the push rod 5 passes through the iron core 201 and connects to the armature 202, and the other end connects to the valve stem 6. The valve stem 6 is movably arranged in the valve seat 7. Fuel enters from the top of the upper housing 1, flows downward through the armature 202, the iron core 201, and the lower housing 3, and then enters the valve seat 7. Driven by the push rod 5, the valve stem 6 forms a sealed state with the valve seat 7, which prevents fuel from being injected outward through the nozzle plate 4, or an open state, which allows fuel to be injected outward through the nozzle plate 4.

[0115] Optionally, referring to Figure 1, the injection valve applicable to multiple fuels in this embodiment further includes a valve core bushing. The housing includes a gland and a shell. The gland, the shell, and the valve core bushing are detachably connected from top to bottom to form a press-fit cavity with a lower opening. In the press-fit cavity, the nozzle plate is disposed at the opening of the valve core bushing, and the valve seat is disposed above the nozzle plate. The solenoid valve assembly, the push rod, and the valve stem are sequentially assembled in the press-fit cavity. A fuel inlet is provided on the shell.

[0116] Optionally, referring to Figures 6, 7 and 8, the housing in this embodiment includes an upper housing 1 and a lower housing 3, the upper housing 1, the lower housing 3, the valve seat 7 and the nozzle plate 4 are connected in sequence; the solenoid valve assembly 2, the push rod 5 and the valve stem 6 are sequentially assembled in the space enclosed by the upper housing 1, the lower housing 3, the valve seat 7 and the nozzle plate 4.

[0117] In the embodiments of this application, various fuels are used, such as methanol, ammonia, hydrogen, fuel oil, gasoline, dimethyl ether, etc.

[0118] Referring to Figure 8, the coil 204, frame 203, wires and fuel are completely physically isolated by the isolation plate 205, which ideally solves the corrosion problem of methanol, ammonia or hydrogen on the injection molding material of the solenoid valve.

[0119] Referring to Figure 6, optionally, the upper ends of the upper housing 1 and the lower housing 3 are screwed together and fixed by a lower housing fastener 8; the upper end of the valve seat 7 extends into the lower end of the lower housing 3 and is screwed together and fixed to the lower housing 3 by a valve seat fastener 9; a second O-ring is provided inside the lower housing 3, forming an internal pressure seal with the inner wall of the valve seat fastener 9; the valve seat 7 and the nozzle plate 4 are screwed together and fixed by a nozzle plate fastener 10. The upper end of the lower housing 3 is inserted into the lower end stop of the upper housing 1, and the two share the lower housing fastener 8 on their outer periphery. After the threads are tightened, a shoulder-to-shoulder compression is formed to ensure the axial sealing between the solenoid valve chamber and the fuel chamber. The first shaft section of the valve seat 7 extends into the lower end inner hole of the lower housing 3, and the valve seat fastener 9 is screwed in from the outside of the lower housing 3 and presses against the shoulder of the valve seat 7, realizing the coaxial positioning and end face sealing of the valve seat 7 and the lower housing 3. The nozzle plate 4 is located on the end face of the second shaft section of the valve seat 7. The nozzle plate fastener 10 is fitted onto the external thread of the valve seat 7. After tightening, the nozzle plate 4 is pressed against the outlet end face of the valve seat 7 to form a high-pressure seal and fix the nozzle plate 4.

[0120] The upper housing 1, lower housing 3, valve seat 7, and nozzle plate 4 are connected and fixed as a whole by the lower housing fastener 8, valve seat fastener 9, and nozzle plate fastener 10. A shoulder shaft and countersunk hole method is used to ensure good coaxiality among the multiple parts, thus preventing jamming between the push rod 5 and the first guide cylinder 206 of the solenoid valve assembly 2, and between the valve stem 6 and the inner hole of the valve seat 7. The upper housing 1, lower housing 3, valve seat 7, and nozzle plate 4 are axially compressed and radially positioned through threaded fastening and stepped positioning, forming a multi-stage sealing cavity structure. This structure not only ensures the coaxiality between the components but also enhances the structural stability and sealing reliability of the injection valve under medium-pressure operating conditions.

[0121] Referring to Figure 7, a filter screen 107 is tightly fitted at the inlet of the upper housing 1, achieving a filtration accuracy of up to 25 μm without throttling, thereby improving the tolerance of the injection valve when injecting different fuels. Referring to Figures 6 and 13, two first threaded holes 106 and two side flats are machined at the end face of the second shaft section of the upper housing 1. The pressure block 11 is fixed to the first threaded holes 106 of the upper housing 1 by hexagonal head screws. The two side flats are configured to constrain the circumferential rotation of the pressure block 11. This pressure block 11 can act as a flange, allowing the injector to be securely installed on the engine intake manifold.

[0122] The solenoid valve, push rod 5, and valve stem 6 constitute a movable valve core system, which are arranged in series along the axial direction within the space enclosed by the housing. Among them, the push rod 5 serves as a force transmission intermediary, with one end connected to the electromagnetic drive component (armature 202) and the other end connected to the fuel control component (valve stem 6), realizing the linear conversion of electromagnetic force into mechanical motion.

[0123] For the solenoid valve in this embodiment, the iron core 201 adopts a bipolar structure with a main magnetic pole and a secondary magnetic pole. A wire lead-out hole 2011 is provided on one side of its lower end, configured to introduce the current of the coil 204 into an external control system. This lead-out method avoids direct contact between the wire and the fuel, improving electrical safety and maintainability. The frame 203 and the coil 204 are assembled between the main and secondary magnetic poles, and the upper surface of the frame 203 is lower than the upper surface of the iron core 201, forming a preset height difference space. This provides thickness matching conditions for the subsequent embedding of the isolation plate 205, ensuring that the isolation plate 205 does not protrude from the end face of the iron core 201 after installation, maintaining the integrity of the magnetic circuit. The isolation plate 205 (e.g., a stainless steel sheet) is fixed in the annular groove between the main and secondary magnetic poles of the iron core 201 by laser welding or other methods, completely covering the frame 203 and the coil 204, achieving a complete physical isolation barrier between the fuel chamber and the electromagnetic components. This structure effectively prevents the erosion of the coil 204 insulation material and the frame 203 by low-lubricating and corrosive fuels such as methanol, ammonia or hydrogen, significantly improving the performance of the solenoid valve in terms of multi-fuel adaptability and long-term reliability.

[0124] Referring to Figure 7, optionally, one end of the push rod 5 passes through the central hole 2012 of the iron core 201 and connects to the armature 202, while the other end is threaded to the valve stem 6, forming a rigid linkage. Referring to Figure 12, the upper end of the push rod 5 has an external thread, which mates with the threaded hole of the armature 202; the lower end of the push rod 5 has a second threaded hole 502, the bottom of which is a countersunk blind hole configured to accommodate the first limiting post 503. The upper end of the valve stem 6 has an external thread, which mates with the second threaded hole 502 at the lower end of the push rod 5. The valve stem 6 is generally inverted "T" shaped, with the lower end forming the valve body, and the back side of the valve body being a spherical arc segment.

[0125] Furthermore, in this embodiment, the valve stem 6 is threadedly connected to the push rod 5, and a first adjusting shim 17 is provided between the upper end face of the valve stem 6 and the threaded hole of the push rod 5. The first adjusting shim 17 is installed in the threaded hole of the push rod 5 with a clearance fit, that is, it is assembled in the second threaded hole 502. By adjusting the thickness of the first adjusting shim 17, the lift can be adjusted. Optionally, the thickness of the first adjusting shim 17 can be adjusted by grinding. Depending on the grinding machine level, the grinding precision can reach the micron level, thereby precisely adjusting the lift.

[0126] Optionally, in this embodiment, the armature 202 and the push rod 5 are threadedly connected, and a second adjusting shim 18 is provided between the threaded hole of the armature 202 and the push rod 5. By adjusting the thickness of the second adjusting shim 18, the air gap between the armature 202 and the solenoid valve assembly 2 can be adjusted. Optionally, the thickness of the second adjusting shim 18 can be adjusted by grinding, and the grinding precision can reach the micron level depending on the grinding machine level, thereby precisely adjusting the air gap.

[0127] Optionally, the first shaft section of the center hole 2012 of the iron core 201 is a circular countersunk hole, and the inner side of the second shaft section and the third shaft section are circular flow channels and the outer side are trapezoidal flow channels. The diameter of the circular flow channel on the inner side of the second shaft section is larger than the diameter of the circular flow channel on the inner side of the third shaft section.

[0128] Referring to Figures 7 and 8, a first guide cylinder 206 is installed in the central hole 2012 of the iron core 201 for the push rod 5 to pass through. The first guide cylinder 206 is configured to constrain the circumferential position of the push rod 5 and guide its movement. Specifically, when the push rod 5 reciprocates in the central hole 2012 of the iron core 201, the first guide cylinder 206 provides axial movement constraint and radial positioning for the push rod 5, preventing uneven wear or jamming caused by poor fuel lubrication.

[0129] The valve stem 6 is movably disposed inside the valve seat 7, and its lower end, the valve body, forms a line contact sealing pair with the lower conical surface of the valve seat 7. Referring to Figure 9, when the valve stem 6 moves downward under the action of the push rod 5, the first sealing conical surface 601 and the second sealing conical surface 704 of the valve seat 7 form a conical contact, blocking the fuel flow to the nozzle plate 4 and creating a seal. When the valve stem 6 moves upward, the valve body leaves the valve seat 7, and an annular fuel flow gap 702 is formed between the first sealing conical surface 601 and the second sealing conical surface 704. Fuel enters the accumulator chamber of the nozzle plate 4 through this fuel flow gap 702, achieving injection. This structure, through the coordinated action of mechanical limiting and elastic reset (return spring 13), achieves rapid opening and closing and stable reset of the valve stem 6, ensuring the timeliness and repeatability of the injection response.

[0130] Optionally, the interior of the first guide cylinder 206 is coated with a self-lubricating coating. This coating forms a solid lubricating film with low shear strength and high chemical inertness at the microscopic level. When the push rod 5 reciprocates at high speed under electromagnetic force: firstly, a dual lubricating transfer film is rapidly generated on the outer surface of the push rod 5 through a plastic deformation-adhesion transfer mechanism; in subsequent strokes, the two dual surfaces transform into relative sliding between lubricating films of the same material / lubricating films, significantly reducing adhesive wear and abrasive wear rates; furthermore, the coating itself has a porous oil / fuel storage microstructure, which can adsorb a small amount of fuel in each injection cycle, forming instantaneous liquid-solid synergistic lubrication, compensating for the inherent defect of methanol, ammonia, and hydrogen fuels lacking a natural lubricating boundary film.

[0131] Referring to Figure 7, optionally, the armature 202 is provided with a first fuel channel 2021, a second fuel channel is formed between the iron core 201 and the push rod 5, a third fuel channel is formed between the lower housing 3 and the push rod 5, a fourth fuel channel is formed between the lower housing 3 and the valve seat 7, and a fifth fuel channel is formed between the valve seat 7 and the valve stem 6;

[0132] The outer wall of the valve seat 7 is provided with a through hole 701 communicating with its internal channel;

[0133] After the solenoid valve assembly 2 is energized, fuel enters from the upper housing 1 and passes sequentially through the first fuel channel 2021, the second fuel channel, the third fuel channel, the fourth fuel channel and the through hole 701 into the fifth fuel channel. It then passes through the fuel flow gap 702 formed between the valve seat 7 and the valve stem 6 and finally flows to the nozzle plate 4 for outward injection.

[0134] The valve stem 6 is coated with a self-lubricating plating.

[0135] By applying a coating to the first guide cylinder 206 and the push rod 5, and the valve seat 7 and the valve stem 6 of the solenoid valve assembly 2 of the injection valve, a self-lubricating effect is achieved, which can prevent the valve core from sticking for fuels with poor lubricity such as methanol, ammonia or hydrogen.

[0136] Multiple first fuel channels 2021 are evenly distributed along the axial direction of the end face of the armature 202, forming a "short-circuit flow" in the electromagnetic attraction zone, allowing the fuel to pass over the lower surface of the armature 202 at high speed, carrying away the local temperature rise caused by the heating of the coil 204, and avoiding the formation of formaldehyde or ammonia gas bubbles from the thermal decomposition of methanol; the porous array generates symmetrical dynamic pressure, which counteracts the radial force imbalance that may occur when the armature 202 moves, reducing the risk of uneven wear between the armature 202 and the pole face of the iron core 201.

[0137] Optionally, the second fuel passage is specifically an annular micro-gap between the central hole 2012 of the iron core 201 and the outer circle of the push rod 5. This second fuel passage acts as a throttling-stabilizing section, attenuating the turbulent pulsations flowing out of the orifice group of the armature 202 into a stable laminar flow, preventing the sealing pair of the downstream valve stem 6 from being subjected to periodic pressure shocks. The annular gap width of the second fuel passage is on the same order of magnitude as the lift of the push rod 5. When the injection pulse width is in the sub-millisecond range, it can form viscous damping, suppressing the overshoot and rebound of the push rod 5, and improving the consistency of the injection pattern.

[0138] Optionally, the third fuel passage is specifically a variable cross-section cavity formed by the multi-stage stepped holes of the upper shell 1 and the outer circle of the push rod 5. The abrupt change in the cross-section of the third fuel passage forms a volume buffer, which absorbs the water hammer peak caused by the pressure fluctuation of the high-pressure common rail and protects the downstream nozzle plate 4 from cavitation damage. The annular expansion-contraction sequence between the cavity wall and the push rod 5 induces the fuel to generate a secondary vortex, realizes the self-stirring effect, and avoids the fuel injection drift caused by density stratification in the ammonia or methanol-diesel dual-fuel mode.

[0139] The fourth fuel passage specifically refers to the annular gap between the lower housing 3 and the valve seat 7. The design of the fourth fuel passage and through hole is as follows: the through hole is evenly distributed circumferentially to form symmetrical inflow, eliminate the lateral hydraulic imbalance force of the valve stem 6, reduce the risk of high-frequency chatter, and improve the service life of the sealing surface.

[0140] The fifth fuel passage specifically refers to the variable area annular band formed by the inner conical surface of the valve seat 7 and the spherical arc back of the valve stem 6. When the lift of the valve stem 6 is greater than 0, the annular band quickly expands into a sickle-shaped flow cross section, realizing a quasi-linear relationship between the equivalent throttling area and the lift. This facilitates the ECU to accurately control the mass flow rate of methanol, ammonia, and hydrogen through pulse width modulation. – The short-length micro-gap section and coarse design reduce viscous pressure loss and compensate for the flow bottleneck caused by the low density and large volumetric flow rate of hydrogen.

[0141] The valve stem 6 reciprocates at high frequency within the fifth fuel passage, and its surface is simultaneously subjected to: mechanical lateral forces (caused by an asymmetric pressure field); and electrochemical corrosion (methanol-formic acid, ammonia-water complexes, and a hydrogen-induced reduction environment). The self-lubricating stop mechanism on the valve stem 6 provides a low-shear-strength transfer film, transforming metal-to-metal wear into film-to-film wear; it also provides a chemically inert barrier, preventing the corrosive medium from contacting the base alloy and avoiding pitting corrosion from becoming fatigue crack initiation sites.

[0142] In addition, the microporous liquid reservoir on the coating surface can adsorb the instantaneous high-pressure fuel in the fifth fuel channel, forming a micro-liquid pad, which provides liquid-solid mixing buffer at the moment the valve stem 6 is closed, reducing the impact stress on the sealing surface.

[0143] The aforementioned five-stage fuel passage sequentially performs multiple functions including heat dissipation, flow stabilization, buffering, steering, and throttling. This allows a single geometric chain to adapt to the vastly different densities, viscosities, corrosiveness, and saturated vapor pressures of the three fuels while maintaining a compact structure. Even under extreme conditions such as ammonia stress corrosion cracking or hydrogen-induced microcracks, the coating can still maintain low friction, ensuring that valve stem 6 does not jam in the fifth fuel passage. Furthermore, the stable back pressure and symmetrical flow field provided by the five-stage fuel passage reduce the mechanical load on the coating, creating a complementary lifespan, resulting in an overall MTBF (Mean Time Between Failures) that exceeds the engine overhaul cycle.

[0144] Referring to Figure 13, optionally, the interior of the upper housing 11 is formed with a first central hole 101, a second central hole 103, a third central hole 104, and a fourth central hole 105 that are sequentially connected and have progressively increasing diameters. The armature 202 is placed in the third central hole 104, with its lower end face maintaining an axial free travel with the stepped surface of the third central hole 104 to ensure the reciprocating motion of the armature 202 during energization and de-energization. The iron core 201 is assembled in the fourth central hole 405, with the two being interference-fitted or shoulder-shaft positioned to achieve radial positioning and axial limiting of the solenoid valve. A stabilizing spring 12 is assembled in the second central hole 102, and the stabilizing spring 12 is configured to limit the static distance between the armature 202 and the iron core 201 when the solenoid valve is de-energized. In this embodiment, the wire lead-out hole 2011 extends from the lower end side wall of the iron core 201, penetrates the wall of the fourth central hole, and leads to the outer wall of the upper housing 1, forming a fuel-isolated wire channel.

[0145] Referring to Figure 7, an upper mounting groove is provided on the stepped surface of the second stepped hole 103, and a lower mounting groove 2022 is provided on the upper end surface of the armature 202. The stabilizing spring 12 is installed between the upper mounting groove and the lower mounting groove 2022. The two ends of the stabilizing spring 12 are respectively embedded in the upper mounting groove and the lower mounting groove 2022 to achieve radial positioning and axial preload, preventing the stabilizing spring 12 from lateral deviation or instability during the reciprocating motion of the armature 202. The function of the stabilizing spring 12 is to maintain the motion state of the armature 202. Even when the armature 202 is in a high-speed motion state, the stabilizing spring 12 ensures that the armature 202 will not experience problems such as uneven wear or radial instability.

[0146] Referring to Figure 13, a first inclined hole 102 is provided between the first stepped hole 101 and the second stepped hole 103. A limiting inclined surface is formed on the wall of the second stepped hole 103 to radially limit the stabilizing spring 12. When fuel flows rapidly through the abrupt change in the stepped cross section, the first inclined hole 102 can immediately introduce or export fluid in the local high-pressure area, weakening the eddy current and necking effect, thereby helping to alleviate the local throttling caused by the step.

[0147] Referring to Figure 13, a fifth O-ring 1051 is provided in the fourth step hole 105, forming an internal pressure seal with the outer wall surface of the iron core 201. Simultaneously, referring to Figure 14, a first O-ring 301 is also provided on the upper end face of the lower housing 3, forming an internal pressure seal with the lower end face of the iron core 201. This method improves the assemblability of the product while ensuring a tight seal.

[0148] Referring to Figure 7, a return spring 13 is connected between the valve seat 7 and the push rod 5. The lower end of the push rod 5 is a disc surface, which serves as the upper seat surface of the return spring 13.

[0149] Referring to Figure 11, optionally, the valve seat 7 includes a first shaft segment and a second shaft segment connected in sequence; the first shaft segment extends into the upper housing 1, and the inner hole of the first shaft segment serves as a guide cylinder for the valve stem 6, ensuring the coaxiality of the reciprocating motion of the valve stem 6 and the alignment of the sealing pair; the second shaft segment is provided with the through hole 701; the shoulder of the second shaft segment is fitted with the bottom stepped hole of the lower housing 3 with a clearance, which not only achieves precise radial positioning of the valve seat 7 and the lower housing 3, but also retains the slight floating required for thermal expansion, preventing coaxiality instability due to marine thermal shock.

[0150] Referring to Figure 11, the outer cylindrical surface 703 of the first shaft section of the valve seat 7 is the guide surface of the return spring 13. The spring seat 14 is placed on the outer cylindrical surface 703. The preload of the return spring 13 can be adjusted by changing the height of the spring seat 14.

[0151] Referring to Figure 12, the first cylindrical pin 15 provided between the upper housing 1 and the lower housing 3, and the second cylindrical pin 16 provided between the lower housing 3 and the valve seat 7, can constrain the rotation of the three components along the axis.

[0152] Referring to Figure 12, the armature 202, push rod 5, and valve stem 6 are connected by threads to form the valve core component, which is a moving part. The valve core and valve body of this injection valve are externally mounted, enabling medium-pressure injection. It features a wide operating pressure range and broad flow coverage, and can be matched with the flow channel area and nozzle parameters of the valve core component to adapt to engines of different power.

[0153] The working principle of the injection valve in this embodiment is as follows: the armature 202, the push rod 5, and the valve stem 6 are connected as a whole by threads. After the solenoid valve is energized, the iron core 201 generates electromagnetic force to attract the armature 202 to move downward. The armature 202 drives the push rod 5 to move downward together. When the lower end face 501 of the push rod 5 contacts the upper end face 705 of the valve seat 7, it stops moving. The fuel passes through the fuel flow gap 702 between the first sealing cone surface 601 of the valve stem 6 and the second sealing cone surface 704 at the lower end of the valve seat 7 and is injected outward through the nozzle. At this time, the injection valve is in the open state.

[0154] After the solenoid valve is de-energized, the return spring 13 pushes the lower end face of the push rod 5 upward, which in turn pushes the push rod 5 to drive the valve stem 6 to move upward together. When the valve body of the valve stem 6 contacts the lower end conical surface of the valve seat 7, it stops moving. At this time, the injection valve is in the closed state.

[0155] The first O-ring 304 and the fifth O-ring 1051 are respectively located on the lower end face and side face of the solenoid valve. This arrangement improves the assemblability of the product while ensuring a tight seal. O-rings are provided on the two shaft sections of the valve seat 7, respectively, to cooperate with the nozzle plate cap 10 and the valve seat cap 9 for sealing. A second O-ring 302 is also provided on the upper threaded end of the lower housing 3, cooperating with the valve seat cap 9 for sealing. The third O-ring 303 and the fourth O-ring 304 are sealing measures at the interface between the injection valve and the external mounting, both providing a double-layer seal. The sealing gasket 402 is located between the nozzle plate cap 10 and the nozzle plate 4. This arrangement ensures that fuel in the accumulator chamber does not leak from the gap between the nozzle plate 4 and the nozzle plate cap 10 when the injection valve is open.

[0156] Referring to Figure 10, the stepped hole of the lower housing 3 and the shoulder of the valve seat 7 are in a clearance positioning fit. This method can improve the coaxiality between the two parts, the lower housing 3 and the valve seat 7, thereby ensuring that there will be no jamming problem between the push rod 5 connected to the valve stem 6 and the first guide cylinder 206 of the solenoid valve. The bottom surface 305 of the stepped hole of the lower housing 3 and the upper end surface 709 of the shoulder of the valve seat 7 are metal sealing surfaces. Under the pressing action of the valve seat cap 9, a high-pressure metal seal is formed, which can effectively seal even highly corrosive and low-viscosity methanol, ammonia, or hydrogen.

[0157] Referring to Figure 12, optionally, in this embodiment, the upper housing 1, lower housing 3, and valve seat 7 are separate parts. The lower end face of the upper housing 1 has a first cylindrical pin hole for installing the first cylindrical pin 15, the upper end face of the lower housing 3 has a second cylindrical pin hole for installing the first cylindrical pin 15, the lower end face of the lower housing 3 has a third cylindrical pin hole for installing the second cylindrical pin 16, and the valve seat 7 has a fourth cylindrical pin hole for installing the second cylindrical pin 16. The first cylindrical pin 15 is placed between the upper housing 1 and the lower housing 3, and the second cylindrical pin 16 is placed between the lower housing 3 and the valve seat 7. This method can constrain the rotational freedom of the upper housing 1, lower housing 3, and valve seat 7 along the axis.

[0158] The solenoid valve wire 207 is led out through the groove on one side of the upper housing 1 and through the outer wall and oblique hole of the second shaft section of the upper housing 1. This method is convenient and quick when disassembling and assembling the solenoid valve and other valve core parts of the injection valve. Compared with the one-piece injection molded solenoid valve, it has good maintainability and interchangeability, and the injection valve has high reliability and low maintenance cost in the later stage. Industrial applicability

[0159] In summary, this application provides a high-pressure differential methanol injector for marine engines, which boasts higher methanol injection pressure. Higher injection pressure means a faster flow velocity of methanol fuel at the nozzle plate. According to fluid dynamics principles, higher flow velocity results in better fuel atomization. Therefore, the high-speed injected methanol fuel is torn into finer droplets at the nozzle, achieving more efficient atomization. This application also provides an injection valve suitable for various fuels, which completely physically isolates the coil, frame, and wires from the fuel through an insulating plate, solving the corrosion problem of methanol, ammonia, or hydrogen on the injection molding material of the solenoid valve and improving the service life of the injection valve.

Claims

A high-pressure differential methanol injector for a marine engine, characterized in that, include: Gland, solenoid valve assembly, housing, push rod, spring, limit plate, valve body, valve core bushing, nozzle plate and valve seat; The gland, housing, and valve core bushing are detachably connected from top to bottom to form a press-fit cavity with an opening at the bottom; Inside the press-fitting chamber, the nozzle plate is positioned at the opening of the valve core bushing, the valve seat is positioned above the nozzle plate, the limit plate is positioned above the valve seat, the spring is limited between the push rod and the limit plate, the lower end of the push rod passes through the limit plate and connects to the valve body inside the valve seat, the upper end of the push rod is connected to the solenoid valve assembly, and a pressure accumulator is formed between the valve body and the valve seat. The housing is provided with a fuel inlet. After methanol fuel enters the housing through the fuel inlet, it passes through the valve seat and enters the accumulator chamber formed between the valve seat and the valve body. Under the combined action of the electromagnetic force provided by the solenoid valve assembly and the methanol supply pressure in the accumulator chamber, the valve body moves together with the push rod, creating a gap between the valve body and the valve seat. The methanol fuel in the accumulator chamber passes through this gap and is ejected outward from each nozzle of the nozzle plate. The high-pressure differential methanol injector for marine engines according to claim 1 is characterized in that, The high-pressure differential methanol injector for marine engines also includes: A limiting seat is provided at the top of the push rod. The electromagnetic force exerted by the solenoid valve assembly on the push rod can be adjusted by adjusting the height of the limiting seat. The high-pressure differential methanol injector for marine engines according to claim 1 or 2 is characterized in that, The solenoid valve assembly includes, from top to bottom, an armature, a solenoid valve, and a yoke; The upper end of the push rod passes through the yoke and the solenoid valve and is then fixed to the armature. The high-pressure differential methanol injector for marine engines according to claim 3 is characterized in that, The upper end of the armature is provided with a boss, and the outer circle of the boss is fitted with the inner hole with a clearance fit. Multiple balance holes are evenly arranged along the axial direction between the upper and lower end faces of the armature. The high-pressure differential methanol injector for marine engines according to claim 3 is characterized in that, Solenoid valves include: Explosion-proof plug, electromagnetic coil, frame, stainless steel thin-walled sleeve and iron core; A thin-walled stainless steel sleeve is wrapped around the outer surface of the skeleton that is in direct contact with methanol fuel; The yoke is attached to the bottom end of the iron core. The high-pressure differential methanol injector for a marine engine according to any one of claims 1-5 is characterized in that, The push rod is provided with an outer circular boss, and a spring is connected between the limit plate and the outer circular boss, and the spring is sleeved on the push rod. The high-pressure differential methanol injector for a marine engine according to any one of claims 1-6 is characterized in that, The limit plate is provided with an oblong guide hole, and the valve seat is provided with a circular guide hole. The circular guide hole and the oblong guide hole are coaxially arranged. The high-pressure differential methanol injector for a marine engine according to any one of claims 1-7 is characterized in that, The nozzle plate is a thin plate of uniform thickness of 0.8 to 1.2 mm, and multiple micro-holes with a diameter of 0.6 to 0.8 mm are drilled on the nozzle plate; An angle is left between each micro-hole during processing, which allows methanol fuel to be injected circumferentially and / or unidirectionally. The high-pressure differential methanol injector for a marine engine according to any one of claims 1-8 is characterized in that, The lower end of the housing extends into the interior of the valve core bushing and is threaded into it; The gland is pressed onto the upper end of the housing and screwed to the housing with screws. The high-pressure differential methanol injector for a marine engine according to any one of claims 1-9 is characterized in that, The valve body and valve seat achieve a line contact to seal the methanol fuel in the accumulator chamber. An injection valve suitable for multiple fuels, characterized in that, include: The solenoid valve assembly includes a housing, a nozzle plate, a push rod, a valve stem, and a valve seat. The housing, the valve seat, and the nozzle plate are connected in sequence; The solenoid valve assembly, the push rod, and the valve stem are sequentially assembled within the space enclosed by the housing, the valve seat, and the nozzle plate. The solenoid valve assembly includes: an iron core with a wire lead-out hole on one side of its lower end; and an armature arranged above the iron core. A skeleton and a coil wound on it are assembled between the main magnetic pole and the auxiliary magnetic pole of the iron core, and the upper end face of the skeleton is lower than the upper end face of the iron core to form a height difference; an isolation plate is fixed in the annular groove between the main and auxiliary magnetic poles of the iron core and covers the skeleton and the coil, and its thickness matches the height difference; One end of the push rod passes through the iron core and is connected to the armature, and the other end is connected to the valve stem; The valve stem is movably arranged within the valve seat; Fuel enters from the top of the upper housing, flows downward through the armature, the iron core, and the lower housing, and then enters the valve seat. Driven by the top rod, the valve stem forms a sealed state with the valve seat, either preventing fuel from being injected outward through the nozzle plate, or an open state, allowing fuel to be injected outward through the nozzle plate. The injection valve applicable to multiple fuels according to claim 11 is characterized in that, The injection valve applicable to multiple fuels also includes a valve core bushing, and the housing includes a gland and a housing. The gland, the housing, and the valve core bushing are detachably connected from top to bottom to form a press-fit cavity with a lower opening. Within the press-fitting cavity, the nozzle plate is disposed at the opening of the valve core bushing, and the valve seat is disposed above the nozzle plate; the solenoid valve assembly, the push rod, and the valve stem are sequentially assembled within the press-fitting cavity; The casing is provided with a fuel inlet. The injection valve applicable to multiple fuels according to claim 11 is characterized in that, The housing includes an upper housing and a lower housing, which are connected in sequence. The solenoid valve assembly, the push rod, and the valve stem are assembled in sequence within the space enclosed by the upper housing, the lower housing, the valve seat, and the nozzle plate. The injection valve applicable to multiple fuels according to claim 13 is characterized in that, A first guide cylinder is installed in the central hole of the iron core for the push rod to pass through. The first guide cylinder is configured to constrain the circumferential position of the push rod and guide the movement of the push rod. The interior of the first guide cylinder is coated with a self-lubricating coating. The injection valve applicable to multiple fuels according to claim 13 or 14 is characterized in that, The armature is provided with a first fuel channel, the iron core and the push rod form a second fuel channel, the lower housing and the push rod form a third fuel channel, the lower housing and the valve seat form a fourth fuel channel, and the valve seat and the valve stem form a fifth fuel channel; The outer wall of the valve seat is provided with a through hole communicating with its internal channel; After the solenoid valve is energized, fuel enters from the upper housing, passes through the first fuel channel, the second fuel channel, the third fuel channel, the fourth fuel channel and the through hole in sequence, enters the fifth fuel channel, passes through the fuel flow gap formed between the valve seat and the valve stem, and finally flows to the nozzle plate and is sprayed outward. The valve stem is coated with a self-lubricating plating. The injection valve applicable to multiple fuels according to any one of claims 13-15 is characterized in that, The interior of the upper shell is formed with a first central hole, a second central hole, a third central hole, and a fourth central hole that are connected in sequence and whose diameters increase in sequence; The armature is assembled in the third central hole and has a distance between it and the stepped surface of the third central hole, so as to realize the reciprocating motion of the armature; The iron core is assembled inside the fourth central hole; A stabilizing spring is installed inside the second central hole. The stabilizing spring is configured to limit the static distance between the armature and the iron core of the solenoid valve assembly when the power is off. The injection valve applicable to multiple fuels according to claim 16 is characterized in that, An upper mounting groove is provided on the stepped surface of the second central hole, and a lower mounting groove is provided on the upper end surface of the armature. The stabilizing spring is installed between the upper mounting groove and the lower mounting groove. The injection valve applicable to multiple fuels according to claim 17 is characterized in that, A first oblique hole is provided between the first central hole and the second central hole, and a limiting oblique surface is formed on the wall of the second central hole to radially limit the stabilizing spring. The injection valve applicable to multiple fuels according to any one of claims 13-18 is characterized in that, A return spring is connected between the valve seat and the push rod. The injection valve applicable to multiple fuels according to any one of claims 13-19 is characterized in that, The valve seat includes a first shaft segment and a second shaft segment connected in sequence. The first shaft section extends into the upper housing, and the inner hole of the first shaft section serves as a guide cylinder for the valve stem; The through hole is provided on the second shaft segment; The shoulder of the second shaft section is fitted with the bottom stepped hole of the lower housing with a clearance. The injection valve applicable to multiple fuels according to any one of claims 13-20 is characterized in that, The valve stem is threadedly connected to the push rod, and a first adjusting shim is provided between the upper end face of the valve stem and the threaded hole of the push rod; the armature is threadedly connected to the push rod, and a second adjusting shim is provided between the armature and the threaded hole of the push rod.

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