Fuel injectors, particularly injectors for methanol atomization, and related machinery, methods, and uses

Abstract

The present invention proposes an injector (1) having a static impactor (11) capable of spraying a uniform fuel fluid jet generated at an injection nozzle (2) into fine droplets for efficiently spraying a liquid fuel, such as methanol or ethanol, at a low pressure of less than 100 bar. It is preferable that the fluid jet exiting from the nozzle outlet (3) of the injection nozzle (2) of the injector (1) falls onto a spray surface (15) formed by the impactor (11) at a relatively large angle of incidence of at least 60°, thereby obtaining a high shear force and achieving efficient spraying.

Description

Technology Field

[0001] The present invention relates to a fuel injector, or simply an injector, designed and configured to atomize and / or inject liquid fuel.

[0002] An injector consists of an injection nozzle having a nozzle outlet through which a uniform fuel jet can be ejected in a straight line along a predetermined flow direction, and a nozzle valve that allows fuel to flow through the injector nozzle. When the nozzle valve opens, fuel flows through the injection nozzle and is discharged through the nozzle outlet. During operation, continuous pressure may be applied to the inlet side of the nozzle valve. The amount of fuel instantaneously injected from the fuel injector (more precisely, the injection nozzle) can be controlled / set through the duration that the nozzle valve is open, etc.

[0003] The present invention also relates to an internal combustion engine comprising at least one combustion chamber, an intake manifold located upstream (in the direction of fuel flow) of said combustion chamber, and at least one intake valve capable of controlling the flow of a fuel-air mixture from the intake manifold to one or more combustion chambers. Finally, the present invention relates to a method of operating such an internal combustion engine and a specific use of an injector according to the present invention, namely, for atomizing a liquid fuel with a low flash point, such as methanol. Background Technology

[0004] Various fuel injection devices that finely atomize liquid fuel to produce a combustible fuel-air mixture are already known in the technical field. This mixture can be ignited in the combustion chamber / cylinder of an internal combustion engine to drive the engine. In addition to traditional diesel fuel, the use of other fuels, such as methanol, is gradually increasing. Depending on the application, methanol can be injected alongside diesel fuel and atomized sufficiently finely to allow both fuels to operate, particularly simultaneously.

[0005] Another technical constraint considered by the present invention is that in many applications, for example, marine applications, the pressure at which fuel can be supplied to the injector is limited to less than 100 bar (low pressure range) or even less than 20 bar. The problem to be solved

[0006] Based on this technical background, the objective of the present invention is to provide an injector capable of atomizing a new fuel, such as methanol or ethanol, very finely and generating a fuel mist of very fine droplets with a fast injection switching time. For example, the average (depending on temperature) droplet size of the generated fuel mist is in the range of about 200 to 400 µm. The desired fine droplet size, that is, the high atomization of the fuel mist generated by the injector, must be achieved stably and reproducibly to ensure high combustion efficiency and have a positive effect on exhaust gases. means of solving the problem

[0007] To solve these problems, the present invention provides the features of claim 1 for a fuel injector that can be used, in particular, to inject fuel into a desired area of ​​an internal combustion engine. In particular, according to the present invention, to solve the problems occurring in the type of injector mentioned above, the injector comprises a freely suspended impactor that follows the nozzle outlet in the direction of discharge and forms a spray surface positioned obliquely to the direction of discharge to spray fuel. The spray surface may be rotationally symmetric.

[0008] According to the present invention, the impactor is designed as a separate component and can be maintained in a state of being freely suspended above the nozzle outlet by its own suspension (thus, the impactor is not manufactured integrally with the same material as the suspension). In particular, the impactor may be designed as a turned metal part or connected to a separate suspension that secures the impactor above the nozzle outlet via a connection, in particular a bidirectional locking and / or material locking connection.

[0009] The aforementioned suspension can be designed in the form of a single-leg or multi-leg bridge, which will be discussed later. By designing the suspension and the impactor separately, the shape of the impactor's spray surface can be precisely controlled to distribute fuel droplet sizes as uniformly as possible within the injection jet generated by the injector. Furthermore, this design allows for easy replacement of only the impactor while maintaining the suspension, making it convenient, for example, to produce various types of injectors with different injection angles. It is desirable to design the connection between the suspension and the impactor to facilitate impactor replacement (e.g., during injector repair / maintenance).

[0010] The injector according to the present invention is preferably configured in a single jet form to generate a uniform (single jet, preferably rotationally symmetric) injection jet of finely atomized fine fuel droplets and can be used to atomize fuels with high surface tension, such as methanol or ethanol, at a pressure of less than 100 bar. Such an injector is preferably installed in an internal combustion engine (particularly according to claim 16) such that the single jet atomization of the injector is directed only toward a single intake port of the internal combustion engine combustion chamber (thus the entire injection jet of fine droplets flows into this intake port).

[0011] This injector is particularly suitable for the marine sector and / or large industrial engines. Fine atomization of the fuel is crucial for ensuring high efficiency, low fuel consumption, and optimal combustion, as well as improving exhaust emissions.

[0012] This injector design specifically ensures that the entire fluid jet ejected from the nozzle orifice travels a free path through the air and then strikes the spray surface of the impactor, atomizing it into (typically fine) droplets to create the desired spray jet. Thus, since the fluid jet is reflected from the spray surface and deviates from its original direction of outflow, the spray surface can be described or understood as the impactor surface. The degree of deflection for the individual radial components of the fluid jet may vary depending on the external contour of the impactor, which will be explained in more detail later (especially when the spray surfaces have different orientations relative to the direction of outflow). Here, the spray surface can be understood as the part of the impactor surface that the fluid jet strikes as it propagates in a straight line from the nozzle orifice.

[0013] After the fuel injection liquid is finely atomized at the spray surface, the resulting fuel droplets can spread beyond the impactor in the form of a fine fuel mist spray in the direction of outflow. Depending on the size and design of the injector nozzle and impactor, as well as pressure, temperature, and (air) backflow, the fine fuel droplet spray generated by the injector can generally exhibit a full opening angle (so-called "injection angle") of 20° to 90° or greater. The injection angle is generally somewhat larger than the impactor's opening angle. For example, using an impactor with a 30° opening angle at a typical operating pressure of less than 20 bar—approximately 8 bar—can result in an injection angle of 35°. The higher the fuel pressure, the greater the difference between the injection angle and the impactor angle. In addition to the operating pressure at the nozzle valve inlet side, temperature, fuel type, and (air) backflow acting on the fuel during the atomization process (e.g., within the intake manifold) also influence the formation of the injection angle. Therefore, testing and / or simulation are generally required to determine the optimal impactor geometry for achieving the desired injection angle.

[0014] Using such an injector makes it possible to achieve high-concentration atomization that produces very fine fuel particles dissolved in air. This is advantageous, for example, when injecting fuel into the intake manifold of a large engine. This is especially true when injecting methanol. The fundamental problem with methanol is that its solubility in air is low due to the significant cooling effect that occurs during the atomization process caused by its high enthalpy. Using the impactor according to the present invention, a fluid jet can be created by generating a finely atomized fuel mist through an impactor that is already in an air environment and, preferably, has almost no limiting factors (described in detail below), and this mist can be injected into a space (e.g., the aforementioned intake manifold) into a specific injection cone (the total opening angle of the "injection angle" of this fuel mist can be 20° to 90° or more depending on the specific design) with almost no obstruction from the impactor.

[0015] A second effect obtainable through the impactor according to the present invention is that high shear force or a large amount of energy is required to break the surface of a methanol fluid and initiate droplet formation / atomization. For example, it must be taken into account that methanol has a higher surface tension than diesel fuel. Using the impactor according to the present invention allows for the generation of such shear force to a sufficient level.

[0016] The original concept of the present invention is to use a splash guard (preferably designed separately from the splash guard) that is freely suspended in space along the nozzle opening, which enables sufficient atomization of methanol, particularly when a fluid pressure of less than 20 bar is applied to the injector. This is particularly important in the marine sector, where engines in which fuel injectors can be used operate at low pressures, typically 10 to 12 bar or less in the fuel supply line for safety reasons. Using the fuel injector according to the present invention allows for the operation of even the generally very large cylinder cross-sectional areas of marine engines.

[0017] According to the present invention, the above problem can also be solved through more advantageous embodiments as defined in the dependent claims and described in detail below.

[0018] To increase fuel atomization efficiency, it is advantageous for the atomization zone to be located inside a virtual cone with a vertex facing the nozzle exit, and for the maximum opening angle 2φ to be up to 130°. However, for certain applications requiring a small atomization angle, it may be advantageous for the maximum opening angle 2φ to be up to 60°, up to 45°, or even up to 35°. For example, in the case of a cone-shaped impact pin with diameter D = 2r and height H, the maximum opening angle is given by 2φ = 2 arcsin [r / H] = 2 arcsin [D / 2H].

[0019] As will be explained in more detail later, this shape generates high shear forces within the fluid jet, promoting efficient and fine atomization of fuel even at low fluid pressures. If the total opening angle of the imaginary cone defining the spray area is, for example, 2 x 30° = 60°, and the impactor is designed as a cone with a rotationally symmetric spray area, it can be guaranteed that the angle of incidence (θ) at which the fluid jet strikes the spray area is always at least 90° - 30° = 60°. If a smaller opening angle is selected, the angle of incidence (θ) becomes larger accordingly.

[0020] In such designs, the impactor can have a cross-sectional area that increases as it moves away from the nozzle exit, while maintaining a relatively slender or elongated shape in the direction of outflow. For example, these characteristics can be realized by making the impactor slender and conical, but other shapes, particularly those that are not rotationally symmetric, are also possible. For instance, the spray surface can be made curved, or it can be designed to have "indentations" or edges.

[0021] It should also be noted that the opening angle of the spray cone (also known as the spray angle or fan angle) of the fine droplets ejected from the impactor is generally somewhat larger than the opening angle of the imaginary cone on which the impactor is located. Therefore, by properly designing the shape of the impactor, the spray angle can be precisely adjusted according to application requirements. However, for efficient spraying, it is advantageous to keep the impactor's opening angle relatively small.

[0022] In addition, for efficient atomization, it is advantageous to select the maximum diameter D3 that the atomization area fills in the radial plane perpendicular to the outflow direction as follows: D3 ≥ 0.50 D1, preferably D3 ≥ 0.85 D1, or particularly preferably D3 ≥ 0.90 D1, or even D3 ≥ D1 (where D1 is the diameter of the nozzle outlet). In some cases, D3 may be selected to be at least 10% larger than D1. This configuration allows the atomization area to be affected even to the outermost radial part of the fluid jet (i.e., the region off-axis of the fluid jet cross-section). On the other hand, if the diameter D3 is less than 0.8 times D1 (e.g., D3 = 3.1 mm, D1 = 2.5 mm), efficient atomization is generally no longer achieved for all fuels. Depending on the type of fuel, usable results can be obtained even at lower values.

[0023] Another preferred embodiment is to have the impactor suspended by the suspension device so that the extension of the spray surface facing obliquely toward the outflow direction (outflow direction direction) is always empty within a specific angle range. This angle range is defined as the angle of rotation around the outflow direction in a radial plane perpendicular to the outflow direction. This empty angle range may be at least 150° or at least 180°, but preferably at least 240° or at least 300°. This feature allows the fuel sprayed by the impactor to be discharged out of the injector without obstruction within the empty angle range while moving obliquely toward the original outflow direction, so as not to come into contact with any component of the fuel injector. If the impactor is suspended, for example, from a bridge with only two legs, the spray may initially be separated (but later merged back into a single spray). For example, if the outflow direction is considered as the z-axis of an orthogonal coordinate system, the angle of rotation around the z-axis lies in the xy plane (radial plane perpendicular to the outflow direction).

[0024] Alternatively, the impactor can be suspended using a suspension system, in which case the radial plane perpendicular to the outflow direction in the frontal region of the impactor is completely empty except for the suspension. This is particularly advantageous because, in this manner, the area where the surrounding gases (air, exhaust gas, or a mixture of both) come into contact with the generated injection jet is the only one, allowing for the efficient atomization of fuel based on shear force (turbulence) to occur without prior interference.

[0025] In particular, this design prevents excessive deposition on downstream structures when fine fuel droplets formed in the impactor continue to fly past the impactor at an angle equal to or oblique to the direction of flow. In injectors with a relatively narrow and perfectly circular nozzle opening where the fluid jet already atomized in the impactor must be ejected first, a tendency for the already atomized fuel to deposit on the inner wall of the injector has been observed. In this case, the droplets recombine, making it impossible to achieve the desired small droplet size and high atomization. The design described above significantly prevents such deposition of the already atomized fuel. Except for thin bridges to which the impactor is suspended, mounted, or formed, the entire finely atomized fuel jet ejected from the impactor can be ejected into the injector without the droplets coming into contact with other elements of the injector.

[0026] In a preferred embodiment, it is proposed that not only the extension of the spray surface in the direction of fuel flow, but also the virtual second cone region radiated from the impactor tip be kept clean (at least partially) within the aforementioned angle range. Here, the total opening angle of this second virtual cone is selected to be at least 20°, preferably 40°, larger than the total opening angle of the first virtual cone on which the impactor is located or surrounding the impactor. Simply put, in this case, only the essential bridge or rib on which the impactor is suspended casts a ceramic tip over the microdroplet jet ejected from the impactor. Otherwise, the microdroplet jet generated from the impactor can propagate unimpeded into the surrounding space without additional contact with the injector, thereby maintaining the small droplet size generated.

[0027] Depending on the application, this design can form a spray cone, for example, that is ejected from an impactor, allowing fine fuel droplets to spread out at a fully open angle between 40° and 90° (depending on the design) in a free angle region that does not touch the wall (i.e., the phenomenon of settling in the injector).

[0028] To generate a uniform fluid jet, it is advisable to keep the exit end of the exit channel leading to the nozzle exit (i.e., near the nozzle exit) clean, and preferably keep it completely clean along its entire axial length. In this case, the fluid jet exiting the nozzle exit may have, for example, a circular cross-section. While a non-circular cross-section is also possible, it is desirable for the cross-section of the fluid jet to form a continuous surface without holes, which is achievable with the aforementioned design.

[0029] For example, the impactor can be suspended from one leg or side above the nozzle outlet. In this case, the suspension system must be designed to be robust to prevent unnecessary vibration of the impactor during injector operation.

[0030] In a preferred embodiment, the impactor is freely suspended above the nozzle outlet by a bridge. This bridge may be designed in the form of a thin web supported, for example, on one or both sides. The bridge may have two legs supported, for example, by injectors on the left and right sides of the impactor, particularly injection nozzles.

[0031] A preferred embodiment is designed so that the bridge in question has three legs supported by the injector, specifically the injection nozzle. Specifically, if the jet ejected from the nozzle outlet strikes the impactor at a slightly oblique angle rather than exactly the center, vibrations may occur in the impactor, which can negatively affect the formation of a spray mist consisting of fine fuel droplets. While a three-legged bridge design may appear to have the disadvantage of requiring a smaller allowable angle range (at the same leg dimensions) compared to a two-legged design, it offers the significant advantage of less vibration in the bridge and the impactor when the fluid jet strikes the impactor. This is because the three legs absorb the lateral forces acting on the impactor more effectively. Preferably, the three legs can be evenly distributed along the circumference (e.g., at 120° intervals).

[0032] The impactor may have a rounded tip near the nozzle. This prevents the tip from deforming during operation and affecting the spray pattern / atomization.

[0033] To prevent the fluid jet from being unnecessarily dispersed before reaching the spray surface of the impactor, a design can be made in which the free axial distance (L1) along the outflow direction between the nozzle tip and the nozzle outlet of the impactor is selected to be small as follows: L1 ≤ 1.75 D1 (approximately: L1 = 5 mm, D1 = 3.1 mm), or L1 ≤ 1.50 D1, or even L1 ≤ D1 (where D1 is the diameter of the nozzle outlet). These dimensional settings ensure that the fluid jet reaches the impactor in a uniform form even after traveling a relatively short distance in the air. For example, if the nozzle outlet diameter is 3.1 mm, the axial distance (L1) is preferably in the range of [2.0 - 2.6] mm. Thus, 0.6 ≤ L1 / D1 ≤ 0.9 can be applied. The exact value of L1 depends particularly on the operating pressure of the fuel used and can be optimized through testing.

[0034] Depending on the design, the distance (L1) may be 0 or have a negative value. In the latter case, the nozzle end of the impactor protrudes into the nozzle exit hole or even goes completely inside.

[0035] For the most efficient spray possible, the impactor must be elongated, as mentioned earlier. Therefore, one design approach is for the axial length (L2) of the spray surface along the outflow direction to be greater than the diameter (D1) of the nozzle outlet. However, for example, if a spray angle greater than 90° needs to be obtained, the design may also be such that the diameter of the impactor is greater than the axial length. In this case, the maximum opening angle (2φ) taken by the impactor can be greater than 90°.

[0036] Additionally, the axial length (L2) of the spray surface may be provided additionally or alternatively such that it is greater than the axial length (L3) of one of the outlet channels of the spray nozzle, and this outlet channel is open to the nozzle outlet, and / or is greater than the free axial distance (L1) between the nozzle tip of the impactor and the nozzle outlet.

[0037] To atomize a sufficient amount of fuel based on the single-hole nozzle concept, the diameter (D1) of the nozzle outlet can be at least 0.5 mm or up to 1.5 mm. Thus, the fuel can be ejected through the nozzle outlet as a single, uniform liquid jet. As the nozzle outlet becomes smaller, the need for an impactor decreases.

[0038] Generally, the preferred shape of the impactor is one in which the cross-sectional area increases in the direction of discharge. However, the impactor does not necessarily have to have strict conical symmetry. Nevertheless, in a preferred embodiment, the impactor is designed in a conical shape that tapers toward the nozzle exit. This cone is preferably designed to taper to a sharp point so that the nozzle tip can be made as fine as possible. Additionally, this cone may be rotationally symmetric. In such a design, the sides of the cone can form the aforementioned spray surface. This allows for the creation of a geometrically precise spray jet of fine droplets with a uniform droplet density distribution.

[0039] A particularly preferred embodiment is characterized in that the cone is designed as a straight plumb, and the longitudinal axis of the straight plumb is preferably aligned with the direction of outflow. That is, the longitudinal axis may specifically align with the central longitudinal axis of the outlet channel of the injection nozzle described above. Additionally, it is preferable that the total opening angle 2φ of the straight plumb forming the impactor is 5° or more or 10° or more. Depending on the application, it is also preferable that the total opening angle 2φ is 135° or less (e.g., when aiming to achieve an injection angle of 90° or more), 90° or less (e.g., when aiming to achieve an injection angle slightly higher than 90°), 70° or less, or less than 45° (e.g., when aiming to create an injection angle of 35°).

[0040] When the longitudinal / rotational axis of the circular cone / cone / impactor aligns with the center axis of the injection nozzle outlet channel, the cone / circular cone is positioned at the center of the nozzle outlet, and its apex faces in the opposite direction to the flow direction. Each of these angle ranges can cause the cone to have a very slender and axially elongated shape.

[0041] The inventive concept for implementing efficient spraying in an impactor having an inclined spray surface can be specifically described as follows. The normal to the spray surface must form an angle of incidence of at least 60°, preferably at most 85°, with respect to the outflow direction of the fluid jet (an angle of incidence of 0° corresponds to a steep perpendicular incidence to the impactor surface). Through this configuration, all components of the fluid jet collide with the spray surface at a relatively large angle of incidence of at least 60°, that is, at a relatively gentle angle.

[0042] In other words, the spray surface itself must be positioned at an angle of 30° or less, preferably at least 5°, with respect to the direction of outflow. For example, this can be achieved by making the impactor into a slender, elongated conical shape. This provides a significant technical advantage that enables particularly efficient spraying by generating high shear forces within the fluid jet. This is because, due to the large angle of incidence, the radially outer component of the fluid jet reaches the spray surface much later than the adjacent radially inner component. While the inner component of the fluid jet has already reached the spray surface and changed direction, the outer component continues to move at high speed from the beginning. A difference in magnitude and direction of the velocity vectors of the paraxial and paraxial components occurs in the cross-section of the fluid jet exiting the nozzle, generating the high shear forces necessary for efficient fuel spraying.

[0043] The spray concept according to the present invention is particularly suitable for spraying fuel at low pressure. Accordingly, the fuel injector can be designed as a low-pressure injector operating at a fuel fluid pressure of less than 100 bar, particularly less than 20 bar. For example, the maximum wall thickness of the injection nozzle can be less than 2 mm, so the robust design required at an operating pressure of 1000 bar is not necessary.

[0044] According to the concept of the present invention, since direct operation of the nozzle valve is more desirable, the fuel injector may include an actuator (preferably electromagnetic) for direct operation of the nozzle valve. For example, the actuator may be designed as an electromagnetic linear actuator. Additionally, the injector may include a flux-blocking sleeve that blocks the magnetic field from the actuator and simultaneously ensures a fluid seal between the fuel and the actuator. One of the advantages of this integrated direct operation is that it is suitable for rapid operation in the desired low-pressure range, enabling short and precise switching times, and eliminates the need for a separate / pilot-operated servo valve.

[0045] For example, when an injector is modified and mounted on an engine, it can be designed and configured to spray and inject fuel, particularly methanol, into the intake manifold of an internal combustion engine. To achieve this, a circular outer sealing ring can be incorporated into the injector nozzle so that it can be sealed against the wall of the intake manifold. As will be explained later, the injector can also be designed and configured to inject fuel into the combustion chamber of a heating device.

[0046] The injection nozzle can preferably be designed as a single-hole nozzle. In this case, the nozzle outlet orifice is the only opening of the injection nozzle through which fuel can be discharged. Therefore, this method differs from conventional multi-hole nozzles. In a multi-hole nozzle, multiple injection jets are ejected from multiple openings. Since these jets generally diverge and overlap at a distance greater than a certain distance from the nozzle openings, a problem often arises where individual injection jets, or more precisely, the droplets contained within them, recombine to obtain the desired fine droplet size. In the concept according to the present invention, when a fluid jet is ejected from a single nozzle outlet orifice (preferably located at the center of the impactor), it generates only a single diverging but uniform jet consisting of the finest fuel droplets after impacting the impactor, thus precisely resolving this problem.

[0047] The nozzle valve may have a valve seat, for example, which may be annular in shape. When the nozzle valve is opened, an annular gap is created, allowing fuel to flow into the outlet channel without interruption of flow. Additionally, the nozzle valve may have a closing portion, which is preferably mounted to move axially along the outflow direction and contacts the valve seat when the nozzle valve is closed to seal the valve seat or the nozzle valve.

[0048] The present invention provides a design of the valve seat as a conical nozzle seat to enable a particularly fast response of the injector. This design may also be considered a pinhead nozzle. In any case, it is a single-hole nozzle.

[0049] That is, the closing portion that closes the valve seat when the nozzle valve closes can be configured to enter a conical seat (preferably tapered) (located inside the nozzle valve). In this case, the inlet contour of the conical seat can form the valve seat. In a preferred embodiment, the conical seat is directly connected to the outlet channel of the injection nozzle, and the outlet channel itself is connected to the nozzle outlet of the injection nozzle. That is, the cone has a central through-opening connected to the outlet channel, and fuel flows into the outlet channel through this opening. This nozzle valve design is particularly advantageous for preventing flow separation and the resulting turbulence, and thus can maintain the velocity distribution of the fuel ejected from the nozzle as uniformly as possible. Consequently, the fuel flow field at the outlet nozzle is uniformly aligned and exhibits a uniform velocity distribution across the entire cross-section of the ejected fuel jet.

[0050] For optimal fluid flow uniformity, it is particularly advantageous that the axial length L4 of the conical seat along the outflow direction measured from the start of the outlet channel to the valve seat is at least 20% of the axial length (L3) of the outlet channel. In this case, the conical seat fluidically forms a kind of (potentially a second) chamber where fluid flow can be uniformized (especially when a distributor is used upstream of the valve seat). Preferably, a rounded cross-section can be provided at the transition from the conical seat to the outlet channel to further optimize flow characteristics. Additionally, it is more desirable that the entire outlet channel, and preferably a portion of the conical seat, remain unblocked when the valve is closed. That is, the valve body should only partially penetrate the conical / conical seat and not penetrate the outlet channel. This allows for the creation of a desired uniform fluid jet.

[0051] Unlike so-called multi-hole nozzles, the nozzle outlet diameter (D1) of the injector can be at least 0.5 mm or at least 1.5 mm to spray a sufficient amount of fuel in a short time.

[0052] Additionally, regarding the ratio of the minimum diameter D4 of the fuel supply channel located upstream of the nozzle outlet of the nozzle valve and particularly configured in a closed body to the nozzle outlet diameter (D1), it can be specified that D1 ≥ 0.3 / D4, preferably D1 ≥ 0.4 / D4. This feature can support the fact that fuel can be supplied with a fast switching time by the injector, particularly the actuator, and ejected as a uniform liquid fluid jet at the nozzle outlet.

[0053] Preferably, the nozzle valve may have a movable closing part to close the valve seat (designable as previously described), and this closing part may be operated electromagnetically, that is, in a direct actuation manner using an electromagnetic actuator as previously mentioned. Thus, the nozzle valve can be designed to be electromagnetic, direct actuation, or electronically controlled. This allows for precise control of the timing and duration of fuel injection, and above all, allows for variable adjustment over time. Furthermore, very short switching times of less than 2 ms can be achieved, and the switching point can be set with great precision. However, the typical switching time in actual applications is likely to be around 20 ms. In this method, the actuator drives the nozzle valve directly, rather than indirectly through fluid pressure as in the case of using a servo valve.

[0054] Alternatively, the injector according to the present invention may be equipped with a nozzle valve that is operated mechanically or hydraulically depending on the requirements of a specific application field.

[0055] To reduce injector switching time and achieve a uniform fluid jet, one design utilizes a distributor in the valve-closed body to form or provide a fuel supply channel divided into at least two channel arms / two lines. This ensures that fuel is always uniformly filled into a pre-chamber, preferably annular, located upstream of the valve seat in the direction of fuel flow, even when the nozzle valve is closed. Consequently, fuel is retained in the pre-chamber just near the valve clearance / valve seat and can wait until the valve opens, enabling virtually immediate fuel injection. This is advantageous for achieving excellent short-duration spray characteristics (a difficult challenge with other spray concepts, such as swirl nozzles).

[0056] This valve design enables rapid valve response and opening even at low fluid pressures of less than 20 bar. The pre-chamber ensures that fuel flows evenly through the relatively wide cross-section of the valve opening in the valve seat area and is always filled with fuel. Fuel passing through the valve opening in the valve seat area from the pre-chamber flows through the common outlet channel of the injector nozzle. This channel is located upstream of the nozzle outlet and preferably has a circular cross-section. This ensures that after passing through the outlet channel, the fuel is ejected from the nozzle outlet in the form of a uniform liquid jet. Thanks to the nozzle design, a uniform velocity distribution is achieved across the entire jet cross-section, which is an essential condition for the effective atomization of the fuel.

[0057] Likewise, for rapid injector switching, it is advantageous for the minimum diameter D2 of the nozzle valve seat to be at least 1.5 times, preferably 2 times, larger than the nozzle outlet diameter (D1). This enables the injection of a relatively large amount of fuel with small axial adjustments of the valve body, thereby enabling the desired rapid injector operation. In addition, the design of the distributor described above allows two fluid flows passing through the open valve seat to be combined into one uniform fluid flow, so that a uniform fluid jet is ejected from the injection nozzle outlet.

[0058] In addition, it is desirable that the outlet channel be oriented such that when the nozzle valve is open, the direction of the fluid jet exiting the nozzle outlet coincides with the control / movement axis of the closing part sealing the valve seat. Each of the two aforementioned channel arms may be oriented in the direction of the outflow, thus forming an angle of less than 90°, preferably less than 70°, with respect to the direction of the outflow.

[0059] Particularly for injectors atomizing methanol, it is important to generate high shear forces when the liquid fluid jet strikes the spray surface of the impeller. In this context, a preferred embodiment is designed to have a boundary axially separating a front region and a rear region on the spray surface of the impeller. This boundary can be designed, for example, as a stepped or curved shape, and preferably extends along the longitudinal axis of the impeller. To optimize spray efficiency, the spray surface of the front region is designed to be flatter or steeper with respect to the outflow direction than that of the rear region. This feature allows the normal to the spray surface to form a specific angle of incidence (θ) for the fluid jet at each point with respect to the outflow direction. This angle is larger or smaller in the front region of the spray surface (preferably always, i.e., at all possible points in the front or rear region of the spray surface) than in the rear region. The opening angle formed by the impeller may increase abruptly at the aforementioned boundary or step.

[0060] To solve this problem, an internal combustion engine as already described in the introduction is proposed. According to the present invention, the internal combustion engine comprises at least one fuel injector configured according to the present invention, that is, configured according to one of the claims relating to the injector or as described above. Additionally, said fuel injector is arranged to inject (finely) atomized fuel into the intake manifold or turbocharger of the internal combustion engine.

[0061] In this context, the present invention also proposes a related method for operating an internal combustion engine. Here, a liquid fuel, such as methanol, is finely atomized from the intake manifold through an injector, and the finely atomized methanol / fuel mixture flows from the intake manifold through an intake valve into the combustion chamber of the internal combustion engine. To achieve very fast switching times and synchronization with the combustion process within the combustion chamber, it is desirable for the fuel injector to be electronically controlled and synchronized with the intake valve of the internal combustion engine. To this end, the injector may have an electromagnetically actuated nozzle valve as previously described. Accordingly, the injector may include an electrical / electronic interface capable of receiving a control signal to actuate the nozzle valve.

[0062] This method is particularly suitable for marine engines that need to introduce methanol into the combustion chamber as a second injection through the intake manifold and intake valve (e.g., as an addition to, supplementing, or replacing diesel fuel injected directly into the combustion chamber). This allows the mixture ratio of methanol and diesel to be precisely controlled to 70:30, for example, by using diesel fuel as an ignition source.

[0063] Accordingly, in specific applications of this method, for example, a methanol-diesel-air mixture can be generated / introduced into the combustion chamber, and a diesel injector directly injects diesel fuel into the combustion chamber to initiate ignition. Since the injector according to the present invention injects methanol into the intake manifold due to reasons such as space constraints, the finely atomized methanol mixture must be introduced into the combustion chamber through a freshly opened intake valve. To operate this correctly, a very short switching time of generally 5 to 20 ms must be maintained, and the injection timing must be synchronized with the operating timing of the intake valve. Therefore, electronic control is generally required, which can be implemented through the electromagnetic driving method of the injector according to the present invention described above.

[0064] To enable efficient and environmentally friendly energy production from clean fuel, specific uses of the injector described above, which can be configured according to one of the claims of the present invention, are proposed. These uses include using the fuel injector to enable the efficient combustion of liquid fuel / methanol by atomizing and injecting liquid fuel (e.g., methanol). For example, using the injector according to the present invention, liquid fuel / methanol can be used as fuel by injecting it into the intake manifold or turbocharger of an internal combustion engine, or into the burner of a heating device (particularly in marine applications such as ships). In this way, for example, a ship's hot air blower or superheated steam generator can be efficiently operated with methanol. This method can be used to heat the interior of a ship or to preheat the fuel system, fuel tank, and the ship engine itself (often impossible to cold start) before starting the ship engine. Thus, the present invention makes a particularly significant contribution to the development of ships powered solely by methanol to reduce CO2 emissions in the shipping sector over the long term.

[0065] The present invention will now be described in more detail with reference to exemplary embodiments, but is not limited to these embodiments. Additional embodiments of the present invention may be derived from the following description of preferred embodiments together with the general description, claims, and drawings.

[0066] In the following description of various embodiments of the present invention, the same reference number is assigned to elements that have the same function, even if they differ in design or shape. Brief explanation of the drawing

[0067] FIGS. 1 to 4 illustrate a first embodiment of an injector according to the present invention, Figure 1 shows a perspective view, Figure 2 shows a partial longitudinal section view, Figure 3 shows a rear view, and Figure 4 shows a front view. FIGS. 5 to 7 are similar drawings of a second embodiment of an injector according to the present invention. FIGS. 8 to 10 illustrate a third embodiment of an injector according to the present invention. Figure 11 shows a detailed cross-sectional view of the injector shown in Figure 7. FIG. 12 shows a further enlarged view of the details of FIG. 11, focusing on the impactor according to the present invention. FIG. 13 shows a possible embodiment of an impactor according to the present invention, which has a stepped outer contour, which defines a first front area and a second rear area of ​​the spray surface of the impactor. Specific details for implementing the invention

[0068] FIGS. 1 to 4 illustrate an example of a fuel injector (1) designed according to the present invention, which can be used to finely atomize liquid methanol as fuel. To this end, fuel is introduced into the injector (1) through a fluid connection (22) and enters a fuel supply channel (7) that can be seen in the cross-sectional view of FIG. 2. The fuel supply channel (7) is partially formed in a closing part (6) that is movably mounted to close the valve seat (13) of the nozzle valve (4) of the injector (1), and the fuel moves to a pre-chamber (9) through a channel arm (8) (distributor 10) formed in the closing part (6). This can be particularly clearly seen in the detailed view of FIG. 11, which shows a detailed view of the injector (1) according to FIG. 7. Thus, when fuel pressure is present at the inlet side of the injector (1), the pre-chamber (9) is always filled with fuel even before the nozzle valve (4) opens.

[0069] When a control signal corresponding to the injector (1) is transmitted through the control cable (21) (see FIG. 1), the closed portion (6) is moved electromagnetically in the opposite direction of the z-axis by the actuator (33) in resistance to the return force of the return spring (30) (see FIG. 2) to directly operate and open the nozzle valve (4) of the injector (1). As shown in the figure, the flux blocking sleeve (24) of the actuator (33) maintains a "dry" state so as not to come into contact with fuel, and allows for selective blocking of magnetic flux. When the actuator (33) is operated, fuel flows from the pre-chamber (9) to the conical seat (19) through the valve seat (13) formed by the inlet contour of the conical seat (19), and from there to the outlet channel (12), which then opens to the nozzle outlet (3) of the injection nozzle (2) of the injector (1). This can be clearly seen by comparing Fig. 1 and Fig. 2 (see detailed view in Fig. 11).

[0070] Accordingly, the nozzle valve (4) shown in FIGS. 2 and FIGS. 11 enables the flow of fuel flowing through the injection nozzle (2) in the fuel supply channel (7) to be controlled (specifically, specifically controlled through a suitable control electronic device), and when the nozzle valve (4) is open, a uniform fuel fluid jet can be ejected from the nozzle outlet (3) along the outflow direction (5) (corresponding to the vertical axis of the outlet channel (12)) shown in FIGS. 2 and FIGS. 11.

[0071] The fluid jet ejected from the nozzle outlet (3) travels along a free path (14) in the air (compare FIG. 2 and FIG. 11) and then strikes a spray surface (15) positioned obliquely in the direction of discharge (5). This spray surface is formed by the impactor (11) shown in FIG. 2. The impactor (11), designed as a separate component, is freely suspended above the nozzle outlet (3) by a suspension device (35).

[0072] More precisely, the impactor (11) is designed in the shape of a pointed, slender cone and is freely suspended in front of the nozzle outlet (3) by a bridge (16) having two legs (17) (see FIG. 1). Since the bridge (16) is supported by the injection nozzle (2) by the two legs (17) as can be seen in FIG. 1, the impactor (11) forms part of the injector (1). The impactor (11) is separately manufactured as a turned metal part and then connected to the suspension device (35) designed as the bridge (16) via a rivet connection (38) (see cross-sectional view in FIG. 2; this connection can also be made by other methods such as flanging, welding, or joining). FIG. 5 and 7 also show the aforementioned radial plane (36) in the front area of ​​the impactor (11). This area is completely empty except for the suspension device (35) or its legs (17) (see FIG. 5).

[0073] In both the second embodiment shown in FIGS. 5 to 7 and the third embodiment shown in FIGS. 8 to 10, the impactor (11) has the same shape, namely a right cone shape, and thus has a rotationally symmetric cone shape that tapers to a single point at the nozzle outlet (3). Thus, this injector produces a single, uniform, and rotationally symmetric spray jet (37) (with respect to the droplet distribution in the radial plane) (see FIG. 11). The side of this right cone forms a spray surface (15).

[0074] To generate high shear force when fuel strikes the spray surface (15), this surface is inclined at a shallow angle with respect to the outflow direction (5). Thus, in the configuration of the impactor (11) shown in the drawing, the spray surface (15) is positioned inside a virtual cone, the apex 18 of the cone faces the nozzle outlet (3), and the full opening angle (2φ) is less than 40° (see detail in FIG. 11). As indicated by the dashed line in FIG. 11 (detail in FIG. 7), the injection angle (32) of the injection jet (37) generated in the injector (1) (i.e., the angle range at which the fuel droplet is ejected from the injector (1)) is somewhat large. Using the concept according to the present invention, an injection angle greater than 90° can be generated depending on the requirements of a specific application, in which case the opening angle (2φ) of the impactor (11) can be selected to be correspondingly larger. The desired spray angle can be easily adjusted to meet customer requirements by replacing the impactor (11).

[0075] In the detailed view of FIG. 12, the maximum diameter D3 that the spray chamber fills in the xy-radius plane is selected to be greater than or equal to the diameter (D1) of the nozzle outlet (3), so that the entire fluid jet coming out of the nozzle outlet (3) actually collides with the spray surface (15).

[0076] In the first example shown in FIGS. 1 to 4, the impactor (11) is suspended from a bridge (16) with two legs, as can be clearly seen in the front view of FIG. 4. However, in the examples shown in FIGS. 8 to 10, this bridge (16) is supported by the injector (1) via three legs (17), making the impactor (11) more rigid and vibration-free. In both configurations, the fine droplet jet generated by the atomization of fuel from the impactor (11) can spread into the surrounding space with almost no obstruction. This can be clearly seen in FIG. 4, where only a very narrow angular range in the xy-radius plane (i.e., the 12 o'clock and 6 o'clock directions) is blocked by the bridge (16), and the remaining angular range of more than 300° is left open (see arrows indicated by dashed lines). The same applies to FIG. 9, where three areas are left open, and the sum of these areas exceeds 300°. Therefore, within this empty angle area, fuel can be discharged from the injector (1) without obstruction and without contacting any component of the injector (1) after spraying.

[0077] This also applies to embodiments according to the second and third embodiments. As can be seen in FIGS. 5 and 8, a port 27 is designed as part of the injection nozzle (2) to surround the impactor (11) in a ring shape (closed) to protect it from damage. The cross-sectional view of FIG. 7 clearly shows that the space enclosed by the port 27 where the impactor (11) is positioned is not connected to the external environment except for the front opening (designed as a kind of closed hole), and that no gas supply channel is formed, particularly around the nozzle outlet. Therefore, contact between the fuel droplet and the surrounding gas atmosphere occurs only in the radial plane (36) region shown in FIGS. 5 and 7. This design is highly advantageous for increasing spray efficiency based on shear force, as previously described.

[0078] In FIGS. 7 and 10, it is clearly visible that the front edge (20) of the container (27) is set back significantly from the bridge (16) opposite the outflow direction (5), so that the fuel mist generated by the impactor (11) can be discharged into the room with almost no obstruction (see radial plane (36) in FIG. 5). If one follows the extension of the spray surface (15) in the outflow direction (5) as indicated by the two inner dashed lines in FIG. 11, it is easy to understand that, together with the corresponding front view in FIG. 6, an angular range of more than 300° is secured for the circumferential angle of the xy-radial plane indicated by the block arrow in FIG. 6 in this example as well.

[0079] The outer dashed line in FIG. 11 indicates that the previously mentioned angle range also applies to a virtual second cone extending from the apex 18 of the impactor (11). This second cone has a full opening angle of about 70°, so it is much wider than the cone of the impactor (11). Thus, a jet of fuel with a full injection angle of, for example, 60° can be generated by the injector (1) without the fuel condensing directly on the inner wall of the container (27).

[0080] Looking at the detailed views in FIGS. 11 and FIGS. 12, it can be clearly seen that the outlet channel (12) is maintained unobstructed over its entire length (L3), so that the fluid jet coming out of the nozzle outlet (3) has a circular cross-section. For efficient spraying, as can be clearly seen in FIG. 11, the axial length (L2) is, for example, significantly larger than the diameter (D1) of the nozzle outlet (3) and the axial length (L3) of the outlet channel (12). Conversely, the axial distance (L1) between the nozzle tip 18 of the impactor (11) and the nozzle outlet (3) is smaller than the diameter (D1) and smaller than the axial length (L2) of the spray surface (15).

[0081] In the rotationally symmetric design of the impactor (11) shown in the drawing, the cross-sectional area increases as it moves toward the outflow direction (5). However, a rotationally symmetric shape is not necessarily required depending on the application. For efficient spraying, it is more important to make the angle of incidence (θ) of the fluid jet relatively large through the appropriate direction of the spray surface (15).

[0082] As shown in FIG. 13, a circumferential step may be formed on the spray surface (15) as a boundary (31) separating the axially forward region (28) and the rear region (29). Instead of such a step, the boundary between the two regions (28) and (29) may be continuous, so the angle of incidence (θ) changes continuously rather than abruptly. In the left variation a), the spray surface (15) is oriented at a shallower angle with respect to the outflow direction (5) in the front region (28) than in the rear region (29). In the second variation b) shown on the right, the opposite is true, which is more preferable than variation a).

[0083] For example, FIG. 12 clearly shows that due to the shape of a slender circular cone defining / limiting the spray surface (15) of the impactor (11), the surface normal (indicated by a dashed line) of the spray surface (15) forms an angle of incidence (θ) of at least 60° with respect to the fluid jet ejected from the nozzle outlet (3) with respect to the outflow direction (5). This causes the radially outer region of the fluid jet to reach the spray surface (15) much later than the radially inner region. Consequently, a very high shear force is generated at the moment the inner region reaches the spray surface (15) while the outer region of the fluid jet is still moving in the outflow direction (5).

[0084] Regarding the design of the nozzle valve (4), it is worth noting that the valve seat (13) is designed as a conical nozzle seat. This is because the closing portion (6) is submerged in the conical seat (19) described earlier, and the inlet contour of this seat forms the valve seat (13) of the nozzle valve (4). However, since the closing portion (6) is not completely submerged in the conical seat described earlier but only partially submerged, a conical tapered chamber remains along the valve seat (13) in the direction of flow even when the nozzle valve (4) is completely closed, and this chamber is connected to the outlet channel (12) of the injection nozzle (2) described earlier. FIG. 12 clearly shows that the minimum diameter D2 of the valve seat (13) formed in the inlet contour of the conical seat (19) is at least 50% larger than the diameter (D1) of the nozzle outlet (3). Therefore, even when the nozzle valve (4) is minimally open, a significant amount of fuel can be released through the minute movement of the closing portion (6). Due to the negative z-direction, the injector (1) can achieve a fast switching time.

[0085] In summary, to efficiently atomize fuel such as methanol or ethanol at low pressure of less than 100 bar, an injector (1) is proposed in which a uniform fuel fluid jet generated at an injection nozzle (2) can be atomized into fine droplets over a fixed impactor (11). The fluid jet exiting from the nozzle outlet (3) of the injection nozzle (2) preferably strikes the atomizing surface (15) formed by the impactor (11) at a relatively large angle of incidence of 60° or more to generate a high shear force, and consequently achieves efficient atomization. Explanation of the symbols

[0086] 1: Fuel injector 2: Spray nozzle 3: Nozzle exit (formed at the end of No. 2) 4: Nozzle valve (located upstream of No. 3, controls fuel flow passing through the 2 / 3 point.) 5: Outflow direction (direction of fuel coming out of Exit 3) 6: Closure (Closed 13) 7: Fuel supply channel (designed in 6) 8: Channel arm (branched from 7 to 10) 9: Preliminary chamber 10: Splitter 11: Impactor 12. Outlet Channel (Connects from No. 2 to No. 3; located downstream of No. 13 in the direction of fuel flow) 13: Valve seat (closed by 6) 14: Free path (between 3 and 11) 15: Spray surface 16: Bridge (11 mountable) 17: Legs (16 out of 16, supporting 16 with 2) 18: Nozzle tip (of 11, nozzle side aligned with 3) 19. Conical sheet 20: Edge (of 27) 21: Control cable (for ¼ control) 22: Fluid connection 23: Magnet 24: Flux blocking sleeve (blocks magnetic flux 33 and fluidically seals 33 from fuel) 25: Anchor 26: (External) Seal 27: Courage 28: Front area (of 15) 29: Rear area (of 15) 30: Return Spring 31: Boundary (between numbers 28 and 29) 32: Angle of discharge 33: Electromagnetic actuator 35: Suspension device 36: Radial plane 37: Injection jet (preferably having a rotationally symmetric cross-section) Design parameters D1 Nozzle outlet diameter Minimum diameter of D2 valve seat D3 maximum diameter is filled with a spray area in the radial plane. Diameter of the D4 fuel supply channel L1 L1 free axis distance along 5 between nozzle tip 11 and 3 (L1) L2 15 axial length (along 5) Axial length of L3 12 L4 axis length 19 θ angle of incidence (from 34° to 11° surface) 2φ maximum opening angle (of 11)

Claims

Claim 1 A fuel injector (1) for spraying liquid fuel, comprising: a spray nozzle (2) having a nozzle outlet opening (3) through which a uniform fuel fluid jet can be discharged in a straight line along the outlet direction (5); and a nozzle valve (4) through which a fuel flow can be discharged through the spray nozzle (2), wherein the fuel injector (1) comprises: a freely suspended impactor (11) that is positioned along the nozzle outlet (3) in the outlet direction (5) and forms a spray surface (15) that sprays fuel obliquely with respect to the outlet direction (5), preferably in rotational symmetry, wherein, in particular, the entire fluid jet discharged from the nozzle outlet (3) passes through a free path (14) in the air and then strikes the spray surface (15) of the impactor (11) to be sprayed into fine droplets. Claim 2 In claim 1, - the impactor (11) is connected to a separate suspension device (35) via a connection part (38), particularly a bidirectional locking and / or material locking connection part, said suspension device positions the impactor (11) at the nozzle outlet (3) and / or, - the spray surface (15) is positioned inside a virtual cone, the nozzle tip (18) is directed toward the nozzle outlet (3), and the total opening angle 2φ is at most 130°, at most 60°, at most 45° or at most 35°, a fuel injector. Claim 3 In claim 1 or 2, the maximum diameter D3 that fills the spray surface (15) in a radial plane perpendicular to the outflow direction (5) is selected to satisfy at least D3 ≥ 0.50 D1, or D3 ≥ 0.85 D1, or D3 ≥ 0.90 D1, or D3 ≥ D1, wherein D1 is the diameter of the nozzle outlet (3), and - in particular, the radially outermost part of the fluid jet also strikes the spray surface of the fuel injector. Claim 4 A fuel injector according to any one of claims 1 to 3, wherein the impactor (11) is suspended by a suspension device (35), and the suspension device is designed separately from the impactor (11) so that an extension of the spray surface (15) directed obliquely toward the outflow direction (5) is kept clean in an angle range of at least 180°, preferably at least 240°, with respect to the angle of rotation around the outflow direction (5) in a radial plane perpendicular to the outflow direction (5), and / or a radial plane (36) perpendicular to the outflow direction (5) located in the front area of ​​the impactor (11) is kept completely clean except for the suspension device (35), so that fuel sprayed into the impactor (11) can flow freely without contacting the components of the fuel injector (1) in a particularly clean area / angle range. Claim 5 A fuel injector according to any one of claims 1 to 4, wherein the outlet channel (12) that opens to the nozzle outlet (3) is kept clean at the outlet end, preferably completely, in particular, so that the fluid jet coming out of the nozzle outlet (3) has a circular disc-shaped cross-section. Claim 6 A fuel injector according to any one of claims 1 to 5, wherein the impactor (11) is freely suspended above the nozzle outlet (3) by a bridge (16) having a single leg or two legs (17a, 17b), preferably by a bridge (16) having three legs (17a, 17b, 17c), and the bridge (16) acts as a suspension device (35). Claim 7 A fuel injector according to any one of claims 1 to 6, wherein the axial distance (L1) along the outflow direction (5) between the nozzle tip (18) of the impactor (11) and the nozzle outlet (3) is selected to be smaller than L1 ≤ 1.75 D1, or L1 ≤ 1.50 D1, or even L1 ≤ D1, where D1 is the diameter of the nozzle outlet (3), and the axial length (L2) along the outflow direction (5) of the spray surface (15) of the impactor (11) is selected to be larger than the diameter (D1) of the nozzle outlet (3) or larger than the axial length (L3) of the outlet channel (12) of the injection nozzle (2), and the outlet channel (12) is open to the nozzle outlet (3). Claim 8 A fuel injector according to any one of claims 1 to 7, wherein the cross-sectional area of ​​the impactor (11) increases in the outflow direction (5), or the impactor (11) is designed in a conical shape, preferably rotationally symmetric, tapers toward the nozzle outlet (3), preferably has a rounded end, - particularly, the side of the cone forms a spray surface (15), - preferably the cone is designed in a right conical shape, and particularly preferably the total opening angle 2φ is 2φ ≥ 5°, particularly 2φ ≥ 10°, preferably 2φ ≤ 130°, particularly 2φ ≤ 90°. Claim 9 A fuel injector according to any one of claims 1 to 8, characterized in that each surface normal of the spray surface (15) forms each angle of incidence (θ) of the fluid jet at least 60°, preferably up to 85°, with respect to the outflow direction (5). Claim 10 A fuel ejector according to any one of claims 1 to 9, wherein the fuel injector (1) is provided and configured to atomize and inject methanol, particularly into the intake manifold of an internal combustion engine, and is provided and configured to: - preferably include an electromagnetic actuator (33) to directly actuate a nozzle valve (4), and particularly to fluidly seal the actuator (33) from fuel through a flux blocking sleeve (24), and / or - be designed as a low-pressure injector (1) such that the fluid pressure of the fuel is less than 100 bar, particularly less than 20 bar, and / or - atomize and inject methanol, particularly into the intake manifold of an internal combustion engine. Claim 11 A fuel injector according to any one of claims 1 to 10, wherein the injection nozzle (2) is designed as a single-hole nozzle, and in particular, the nozzle outlet (3) is the only opening of the injection nozzle (2) through which fuel can be discharged. Claim 12 A fuel injector (1) according to any one of claims 1 to 11, wherein the valve seat (13) of the nozzle valve (4) is designed as a conical nozzle seat, or a closing portion (6) that seals the valve seat (13) when the nozzle valve (4) is closed is designed to enter into a conical seat (19) that tapers into a conical shape, or in particular, the inlet contour of the conical seat (19) forms the valve seat (13), or the conical seat (19) leads to an outlet channel (12) of the injection nozzle (2), and said outlet channel (12) is designed to open to a nozzle outlet (3). Claim 13 A fuel injector according to any one of claims 1 to 12, wherein the diameter of the nozzle outlet (3) is at least D1 ≥ 0.5 mm or D1 ≥ 1.5 mm, and in particular, fuel can be discharged from the nozzle outlet (3) as a single uniform liquid fluid jet. Claim 14 A fuel injector according to any one of claims 1 to 13, wherein the nozzle valve (4) preferably has a closing portion (6) movably mounted to close the valve seat (13) of the nozzle valve (4) and, in particular, the closing portion (6) has a fuel supply channel (7) divided into at least two channel arms (8a, 8b) by a distributor (10), and, preferably, a reserve chamber (9) located upstream of the valve seat (13) in the direction of fuel flow is filled with fuel even when the nozzle valve (4) is closed. Claim 15 A fuel injector characterized in that, in any one of claims 1 to 14, the spray surface (15) preferably has a circumferential boundary (31) and is particularly stepped or rounded to separate the axial front region (28) and the axial rear region (29) of the spray surface (15), - the front region (28) of the spray surface (15) is a) flatter or b) steeper in the outflow direction (5) than the rear region (29), - particularly each surface normal of the spray surface (15) forms an angle of incidence (θ) with respect to the outflow direction (5) for the fluid jet, and this angle of incidence in the front region (28) is preferably always greater than or equal to or b) smaller than in the rear region (29). Claim 16 An internal combustion engine comprising at least one combustion chamber, an intake manifold located upstream of the combustion chamber, and at least one intake valve capable of controlling the flow of a fuel-air mixture from the intake manifold to the combustion chamber, wherein the internal combustion engine comprises at least one fuel injector (1) according to any one of claims 1 to 15, arranged to supply finely atomized fuel to the intake manifold. Claim 17 A method of operating an internal combustion engine designed according to Article 16, wherein - liquid fuel, particularly methanol, is finely atomized in the intake manifold by a fuel injector (1) and introduced into the combustion chamber through an intake valve, and - preferably, the fuel injector (1) is electronically synchronized with the intake valve. Claim 18 Use of a fuel injector (1) according to any one of claims 1 to 15 - said fuel injector (1) is used to spray and inject liquid fuel, in particular methanol, and - said methanol is injected in particular into the intake manifold of an internal combustion engine or into a turbocharger or a burner device of a heating device.

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