Fuel injector nozzle, fuel injector, internal combustion engine and vehicle

Abstract

A fuel injector nozzle (9) is provided. The nozzle (9) comprises a nozzle head (9 '), the nozzle head (9') comprising an inner surface (39) and an outer surface (41). The nozzle (9) further comprises a plurality of fuel injection holes (11), each fuel injection hole (11) forming an inlet opening (31) at the inner surface (39) and an outlet opening (32) at the outer surface (41). At least one fuel injection hole (11) has a geometric centre line (c1) which is curved along at least a first portion (p1) of the at least one fuel injection hole (11). The radius of curvature (r1) of the geometric centerline (c1) increases when viewed from the inlet opening (31) in the d1'direction towards the outlet opening (32). The radius of curvature (r1) of the geometric centre line (c1) increases continuously along the entire at least first portion (p1) of the at least one fuel injection hole (11) as viewed from the inlet opening (31) in the d1'direction towards the outlet opening (32). The invention also provides a fuel injector (1), an internal combustion engine (40) and a vehicle (2).

Description

Technical Field

[0001] The present disclosure relates to a fuel injector nozzle configured to inject fuel into a combustion chamber of an internal combustion engine, and further relates to a fuel injector, an internal combustion engine including the fuel injector, and a vehicle including the internal combustion engine. Background Art

[0002] An internal combustion engine, such as a four-stroke internal combustion engine, includes one or more cylinders, each of which is equipped with a piston. The piston is connected to the crankshaft of the internal combustion engine and is arranged to reciprocate in the cylinder when the crankshaft rotates. The internal combustion engine also generally includes one or more intake valves and exhaust valves, and one or more fuel supply devices. The one or more intake valves and exhaust valves are controlled by a respective valve control device. The valve control device generally includes one or more camshafts. The one or more camshafts are rotatably connected to the crankshaft of the internal combustion engine by belts, chains, gears or similar devices. A four-stroke internal combustion engine completes four independent strokes while rotating the crankshaft. A stroke refers to the entire travel of the piston in the cylinder in either direction.

[0003] The strokes are completed in the following order: intake stroke, compression stroke, expansion stroke and exhaust stroke. During the operation of a conventional four-stroke internal combustion engine, the intake valve control device controls the intake valve of the cylinder to remain open during the intake stroke of the piston to allow air or a mixture of air and fuel to enter the cylinder. During the compression stroke, all valves should be closed to allow the air or air and fuel mixture in the cylinder to be compressed. If the internal combustion engine is in a power generation state, the fuel in the cylinder is usually ignited at the end of the compression stroke, for example, by a spark plug or by the heat generated by compression in the cylinder.

[0004] The combustion of fuel in the cylinder greatly increases the pressure and temperature in the cylinder. The combustion of fuel usually continues for a large part of the subsequent expansion stroke. The increased pressure and temperature in the cylinder caused by the combustion of fuel is partially converted into mechanical power applied to the crankshaft during the expansion stroke. Since most of the combustion usually occurs during the expansion stroke, the expansion stroke is also often called the "combustion stroke". In the subsequent exhaust stroke, the exhaust valve control device controls the exhaust valve of the cylinder to remain open to allow exhaust gas to be discharged from the cylinder and enter the exhaust system of the internal combustion engine.

[0005] A fuel injector is a device used to supply fuel to the combustion chamber of an internal combustion engine. Compression ignition engines, such as diesel engines, and some spark ignition engines, such as Otto engines, use fuel injectors configured to supply fuel to the combustion chamber. Gasoline engines equipped with fuel injectors for supplying fuel to the combustion chamber are often referred to as "gasoline direct injection engines". In diesel engines, the injected fuel is ignited by the heat of compression or by a glow plug. In an Otto engine, the injected fuel is ignited by the spark from a spark plug.

[0006] There are other types of fuel injectors, such as those configured to inject fuel into the intake manifold of a gasoline engine. However, these types of fuel injectors are technologically fundamentally different from fuel injectors configured to inject fuel into the combustion chamber and typically operate at significantly lower fuel injection pressures than fuel injectors configured to inject fuel into the combustion chamber. In addition, fuel injectors configured to inject fuel into the combustion chamber of an internal combustion engine face entirely different design challenges than fuel injectors configured to inject fuel into the intake manifold, in part because fuel injectors configured to inject fuel into the combustion chamber are subject to significantly higher peak temperatures and pressures than fuel injectors configured to inject fuel into the intake manifold of an internal combustion engine.

[0007] A fuel injector configured to inject fuel into a combustion chamber of an internal combustion engine typically includes a nozzle having a nozzle tip that protrudes into the combustion chamber. The nozzle tip typically includes a valve seat that is disposed on an inner surface of the nozzle tip, wherein a so-called oil pocket volume is formed between an outer surface of a needle tip of a needle-shaped member and an inner surface of the nozzle tip of the nozzle. In addition, these types of fuel injectors typically include a plurality of fuel injection holes, each of which forms an inlet opening on the inner surface of the nozzle tip and an outlet opening on the outer surface of the nozzle tip. The needle tip typically moves toward or away from the nozzle to interact with the valve seat of the nozzle to open or close a fluid connection between a fuel chamber of the fuel injector and the oil pocket volume. As described above, the nozzle tip is typically configured to protrude into the combustion chamber and therefore includes an outer surface adjacent to the combustion chamber.

[0008] Fuel injector nozzles are key components for achieving fuel economy and emission control in internal combustion engines. The development and upgrading of fuel injectors has increased the fuel injection pressure, which is beneficial for reducing engine emissions, such as the formation of smoke. In addition, fuel injectors have been upgraded to structures that can perform multiple continuous injections in one combustion cycle, which puts forward requirements for the design of fuel injector nozzles. Different injection events in one combustion cycle can include pre-injection, main injection and post-injection. In addition, many fuel injectors can perform multiple continuous pre-injections and post-injections in one combustion cycle through control devices.

[0009] The main injection event needs to be fast and have a larger injection volume than the pilot injection. In addition, the size of the main injection, i.e. the amount of fuel injected during the main injection, varies substantially with engine power output. Therefore, at least in some cases, the fuel injector must be able to inject a large amount of fuel into the combustion chamber. This requirement, coupled with the high injection pressures achieved by the development of fuel injectors, has brought new challenges to the design of fuel injector nozzles.

[0010] In general, it is desirable to design a fuel injector nozzle that keeps the sac volume as small as possible. One reason for this requirement is that when the fluid connection between the sac volume and the fuel chamber of the fuel injector is closed by the needle, fuel is trapped in the sac volume. Due to the lack of oxygen in the sac volume, the fuel here usually does not burn, but is heated by the heat generated by the burning fuel in the surrounding combustion chamber. Heating of the fuel in the absence of oxygen usually results in the formation of soot particles. Therefore, the heating of the fuel in the sac volume increases the emission of soot / smoke and may cause a slight increase in the engine's fuel consumption.

[0011] Additionally, in many engines, it is an advantage if the fuel injector nozzle can be configured with a large number of fuel injection holes. A large number of fuel injection holes can result in a large flame front in the combustion chamber, which can improve the fuel efficiency of the engine because more of the total combustion can occur early in the expansion stroke. Early combustion can improve fuel efficiency because the increased pressure caused by the combustion can produce power over more of the piston's expansion stroke, and when the fuel is burned in the early stages of the expansion stroke, power can be produced over more of the expansion stroke than if the fuel is burned later in the expansion stroke.

[0012] However, as mentioned above, there is a conflict between the need for a smaller fuel sac volume and / or the need for a large number of fuel injection holes, for the simple reason that a large number of inlet openings cannot be arranged on the delimiting surface of a small fuel sac volume. In addition, the inlet openings of the fuel injection holes generally cannot be too close to each other. This is because too small a distance between adjacent inlet openings of the fuel injection holes may lead to hole mixing due to erosion of the nozzle material. Hole mixing due to erosion may lead to nozzle failure.

[0013] Another problem associated with fuel injector nozzles is cavitation. Cavitation is particularly prone to occur around the edges of the fuel injector nozzle inlet opening. The inlet opening of the fuel injector nozzle is located on the inner surface of the nozzle tip on the nozzle. As mentioned above, cavitation can cause the nozzle material to erode and can cause bore mixing, which can lead to nozzle failure.

[0014] Since both the fuel injector and the fuel injector nozzle are key components for realizing the functions of the internal combustion engine, these two components are generally required to be durable and reliable.

[0015] Another problem associated with fuel injector nozzles is the flow characteristics of the fuel flowing through the large number of fuel injection holes in the nozzle. That is, it is an advantage if the design of the nozzle can ensure that the fuel flowing through the large number of fuel injection holes in the nozzle has favorable flow characteristics, thereby optimizing combustion. Summary of the invention

[0016] An object of the present invention is to overcome or at least alleviate at least some of the above problems and disadvantages.

[0017] According to a first aspect of the present invention, the above object can be achieved by configuring the nozzle to be a structure for injecting fuel into a combustion chamber of an internal combustion engine. The nozzle includes a nozzle head, and the nozzle head includes an inner surface and an outer surface. The inner surface forms a bounding surface of an oil sac volume, and the outer surface is configured to be adjacent to the combustion chamber. The nozzle further includes a valve seat, and the valve seat is configured to interact with the needle member to open and close the fluid connection between the oil sac volume and the fuel chamber of the fuel injector. The fuel injector includes the nozzle. The nozzle also includes a plurality of fuel injection holes, each of which forms an inlet opening on the inner surface of the nozzle head and an outlet opening on the outer surface of the nozzle head. Among the plurality of fuel injection holes, at least one fuel injection hole has a geometric center line. The geometric center line is curved along at least a first portion of the at least one fuel injection hole. The radius of curvature of the geometric center line increases from the inlet opening toward the outlet opening, wherein the radius of curvature increases continuously along the entire first portion of the at least one fuel injection hole from the inlet opening toward the outlet opening.

[0018] Since at least one fuel injection hole has a geometric center line which is curved along at least a first portion of the at least one fuel injection hole, conditions are provided for ensuring that the fuel flowing through the at least one fuel injection hole has favorable flow characteristics.

[0019] Furthermore, since the geometric center line is curved along at least a first portion of the at least one fuel injection hole, a reduced inflow angle is provided at an edge of the outlet opening. The outlet opening is arranged at the inner surface of the nozzle head. The reduced inflow angle at the edge of the inlet opening can reduce the tendency of cavitation at the edge of the inlet opening, thereby reducing the possibility of material corrosion around the inlet opening. The inlet opening is located at the inner surface of the nozzle head of the nozzle. Therefore, a fuel injector nozzle is provided to provide for improved durability and reliability.

[0020] Since the curvature radius of the geometric center line increases when viewed from the inlet opening toward the outlet opening, a condition is provided to ensure that there is a reduced inflow angle at the edge of the outlet opening. This is because a small curvature radius of the geometric center line means that the curvature of the at least one fuel injection hole is large, and, since the curvature radius of the geometric center line increases when viewed from the inlet opening toward the outlet opening, a condition is provided to ensure that there is a further reduced inflow angle at the edge of the inlet opening.

[0021] Furthermore, since the radius of curvature increases continuously along the entire first portion of the at least one fuel injection hole as viewed from the inlet opening toward the outlet opening, conditions are provided for ensuring that the fuel flowing through the at least one fuel injection hole has further favorable flow characteristics, and the cavitation tendency of the fuel flowing through the at least one fuel injection hole is reduced.

[0022] Therefore, the provision of the fuel injection hole can overcome or at least alleviate at least some of the above problems and disadvantages. Thus, the above purpose is achieved.

[0023] Optionally, the geometric center line is in a continuously curved state along the first portion of the at least one fuel injection hole. Therefore, conditions are provided to ensure that the fuel flowing through the at least one fuel injection hole has further favorable flow characteristics. In addition, since the geometric center line is in a continuously curved state along the first portion of the at least one fuel injection hole, the cavitation tendency of the fuel flowing through the at least one fuel injection hole can be reduced.

[0024] Optionally, the first portion of the at least one fuel injection hole comprises an inlet portion of the at least one fuel injection hole. This provides for further advantageous flow characteristics of the fuel flowing through the inlet portion of the at least one fuel injection hole. Also, it provides for a further reduced inflow angle at the edge of the inlet opening of the at least one fuel injection hole. Thus, the cavitation tendency at the edge of the inlet opening can be further reduced, thereby also reducing the possibility of corrosion of the material around the inlet opening on the inner surface of the nozzle head.

[0025] Optionally, the length of the first portion of the at least one fuel injection hole accounts for at least 30%, preferably at least 60%, of the total length of the at least one fuel injection hole, the length being measured from the inlet opening to the outlet opening. Thus, conditions are provided for ensuring that the fuel flowing through the at least one fuel injection hole has further favorable flow characteristics. This is because the first portion of the at least one fuel injection hole accounts for a large proportion of the total length of the at least one fuel injection hole. Wherein, the geometric center line is in a curved state in the first portion of the at least one fuel injection hole. Therefore, conditions are provided for ensuring that there is a further reduced inflow angle at the edge of the inlet opening. Specifically, the further reduced inflow angle can reduce the cavitation tendency at the edge of the inlet opening, and can also reduce the possibility of material corrosion around the inlet opening, wherein the inlet opening is located on the inner surface of the nozzle head.

[0026] Optionally, the total length of the at least one fuel injection hole is at least 3 times, or at least 4 times, greater than the diameter of the outlet opening. This provides for further advantageous flow characteristics of the fuel flowing through the at least one fuel injection hole. This is because the total length of the at least one fuel injection hole is very long compared to the outlet opening diameter of the at least one fuel injection hole. This provides for a smaller inflow angle at the edge of the inlet opening, while avoiding excessive curvature of the geometric center line.

[0027] Furthermore, since the total length of the at least one fuel injection hole is very long compared to the outlet opening diameter, it allows for a large number of fuel injector nozzles to be manufactured in a simpler and more cost-effective manner, while also ensuring consistent injection performance between nozzles of a large number of fuel injectors.

[0028] Optionally, the inlet opening is elliptical. This provides for further favorable flow characteristics of the fuel flowing into the inlet opening of the first fuel injection hole. In addition, it also provides for a further reduced inflow angle at the edge of the inlet opening. Furthermore, since the inlet opening is elliptical, it provides for increasing the distance from the edge of the inlet opening of the at least one fuel injection hole to the edge of the inlet opening of the adjacent fuel injection hole. In this way, it provides for a small oil pocket volume and / or a large number of fuel injection holes in the nozzle, while avoiding hole mixing due to corrosion.

[0029] In addition, the distance between the inlet opening edge of the at least one fuel injection hole and the inlet opening edge of the adjacent fuel injection hole is increased, which provides conditions for ensuring that the edge of the at least one fuel injection hole is processed to a greater extent to remove sharp edges and eliminate the risk of hole mixing. The processing can further prevent the formation of cavitation and the resulting corrosion damage to the nozzle material. The inlet opening edge of the at least one fuel injection hole can be processed by, for example, water erosion processing.

[0030] Optionally, the first portion of the at least one fuel injection hole has an elliptical cross section, the elliptical cross section being in a plane perpendicular to the direction from the inlet opening to the outlet opening. This provides for ensuring that the fuel flowing through the first portion of the at least one fuel injection hole has favorable flow characteristics. In addition, it also provides for ensuring that there is a further reduced inflow angle at the edge of the inlet opening. Furthermore, since the first portion of the at least one fuel injection hole has an elliptical cross section, it provides for ensuring that the distance from the inlet opening edge of the at least one fuel injection hole to the inlet opening edge of the adjacent fuel injection hole is increased. In this way, it provides for ensuring that the nozzle has a small oil pocket volume and / or a large number of fuel injection holes, while avoiding hole mixing due to corrosion.

[0031] Optionally, the eccentricity of the elliptical cross section at the inlet portion of the at least one fuel injection hole is greater than 0.3 or greater than 0.5. Thus, conditions are provided to ensure that the fuel flowing through the inlet portion of the at least one fuel injection hole has favorable flow characteristics. In addition, since the eccentricity of the elliptical cross section at the inlet portion of the at least one fuel injection hole is greater than 0.3 or greater than 0.5, conditions are provided to ensure that the distance from the inlet opening edge of the at least one fuel injection hole to the inlet opening edge of the adjacent fuel injection hole is increased. In this way, conditions are provided to ensure that the nozzle has a small oil pocket volume and / or a large number of fuel injection holes, while avoiding hole mixing due to corrosion damage to the nozzle material.

[0032] In addition, the increased distance from the edge of the inlet opening of the at least one fuel injection hole to the edge of the inlet opening of the adjacent fuel injection hole provides conditions for ensuring that the edge of the at least one fuel injection hole is processed to a greater extent to remove sharp edges and eliminate the risk of hole mixing. The processing can further prevent the formation of cavitation and the resulting erosion damage to the nozzle material. The edge of the inlet opening of the at least one fuel injection hole can be processed by, for example, water erosion processing.

[0033] Optionally, the eccentricity of the elliptical cross section is reduced when viewed from the inlet opening toward the outlet opening. This provides conditions for ensuring that the fuel flowing through the at least one fuel injection hole has further favorable flow characteristics, while providing conditions for ensuring a smaller inflow angle at the edge of the inlet opening, and providing conditions for obtaining a small oil pocket volume and / or configuring a large number of fuel injection holes while avoiding hole mixing due to corrosion. In addition, conditions are provided for ensuring that a flow stability zone is obtained toward the outlet opening of the at least one fuel injection hole.

[0034] Optionally, the eccentricity of the elliptical cross section decreases continuously along the entire first portion, as viewed from the inlet opening toward the outlet opening. This provides conditions for ensuring that the fuel flowing through the first portion of the at least one fuel injection hole has favorable flow characteristics, while also providing conditions for ensuring a smaller inflow angle at the edge of the inlet opening, and providing conditions for obtaining a small oil pocket volume and / or configuring a large number of fuel injection holes while avoiding hole mixing due to corrosion. In addition, the cavitation tendency of the fuel flowing through the at least one fuel injection hole can also be reduced.

[0035] Optionally, the eccentricity of the at least one fuel injection hole reaches zero at the boundary between the first part and the second part of the at least one fuel injection hole. This provides conditions for ensuring that the fuel flowing through the first part of the at least one fuel injection hole has favorable flow characteristics. In addition, a flow stabilization zone toward the outlet opening is provided, while providing conditions for ensuring a smaller inflow angle at the edge of the inlet opening, and providing conditions for obtaining a small oil pocket volume and / or configuring a large number of fuel injection holes, and avoiding hole mixing due to corrosion damage to the nozzle material.

[0036] Optionally, the valve seat is arranged to cooperate with a needle-shaped member movable along a displacement axis to open and close the fluid connection between the oil bag volume and the fuel chamber of the fuel injector. The fuel injector comprises the nozzle. And, wherein the elliptical cross section is oriented such that the main axis of the elliptical cross section is substantially parallel to a plane comprising the displacement axis. This provides for ensuring that the fuel flowing through the inlet opening of the at least one fuel injection hole has favorable flow characteristics. In addition, it also provides for ensuring that there is a further smaller inflow angle at the edge of the inlet opening.

[0037] Furthermore, since the elliptical cross section is oriented so that the major axis of the elliptical cross section is substantially parallel to the plane including the movement axis, it is possible to ensure that the distance from the edge of the inlet opening of the at least one fuel injection hole to the edge of the inlet opening of the adjacent fuel injection hole is increased. In this way, it is possible to ensure that the nozzle has a small oil pocket volume and / or a large number of fuel injection holes while avoiding hole mixing due to corrosion.

[0038] In addition, it is possible to ensure that the edge of the at least one fuel injection hole is processed to a greater extent to remove sharp edges and eliminate the risk of hole mixing. Such processing can further prevent the formation of cavitation and reduce erosion damage to the nozzle material. The edge of the inlet opening of the at least one fuel injection hole can be processed by, for example, a water erosion processing method.

[0039] Optionally, the outlet opening is circular. Thus, a condition is provided for obtaining a symmetrical flame structure in the combustion chamber, which can be obtained by injecting fuel from the outlet opening of the at least one fuel injection hole.

[0040] Optionally, the at least one fuel injection hole has a geometric center line. The geometric center line is in a straight line along the second part of the fuel injection hole. Thus, conditions are provided to ensure that a flow stability zone is obtained toward the outlet opening of the at least one fuel injection hole, while also ensuring that the fuel flowing through the first part of the at least one fuel injection hole has favorable flow characteristics. In addition, conditions are provided to ensure that there is a smaller inflow angle at the edge of the inlet opening, and conditions are also provided for obtaining a small oil pocket volume and / or configuring a large number of fuel injection holes, while avoiding hole mixing caused by corrosion damage to the nozzle material. Furthermore, conditions are provided for obtaining a symmetrical flame structure in the combustion chamber, and the symmetrical flame structure can be obtained by injecting fuel from the outlet opening of the at least one fuel injection hole.

[0041] Optionally, the second portion of the at least one fuel injection hole includes an outlet portion of the at least one fuel injection hole. This provides conditions for ensuring that there is a flow stability zone at the outlet portion of the at least one fuel injection hole, and at the same time provides conditions for ensuring that the fuel flowing through the first portion of the at least one fuel injection hole has favorable flow characteristics, while also ensuring that there is a smaller inflow angle at the edge of the inlet opening, and provides conditions for obtaining a small oil pocket volume and / or configuring a large number of fuel injection holes, while avoiding hole mixing due to nozzle material being. In this way, a symmetrical flame structure can be obtained in the combustion chamber, and the symmetrical flame structure can be obtained by injecting fuel from the outlet opening of the at least one fuel injection hole.

[0042] Optionally, the length of the first portion of the at least one fuel injection hole is greater than the length of the second portion of the at least one fuel injection hole. This provides a condition for ensuring that there is a flow stability zone at the outlet portion of the at least one fuel injection hole, and at the same time ensures that the fuel flowing through the first portion of the at least one fuel injection hole has further favorable flow characteristics and a smaller inflow angle at the edge of the inlet opening. In addition, it provides a condition for obtaining a small oil pocket volume and / or configuring a large number of fuel injection holes, while avoiding hole mixing caused by corrosion damage to the nozzle material.

[0043] Optionally, the second portion of the at least one fuel injection hole has a circular cross section on a plane perpendicular to the geometric center line of the second portion. This provides conditions for ensuring that there is a flow stability zone in the second portion of the at least one fuel injection hole, and provides conditions for obtaining a symmetrical flame structure in the combustion chamber, which can be obtained by injecting fuel from the outlet opening of the at least one fuel injection hole.

[0044] Optionally, the inlet opening of the at least one fuel injection hole has an effective cross-sectional area, which is larger than the effective cross-sectional area of ​​the outlet opening of the at least one fuel injection hole. This provides conditions for ensuring that the fuel flowing through the at least one fuel injection hole has favorable flow characteristics and for ensuring that a smaller inflow angle exists at the edge of the inlet opening.

[0045] Optionally, the effective cross-sectional area of ​​the at least one fuel injection hole decreases continuously along the entire first portion of the at least one fuel injection hole. This provides for ensuring that the fuel flowing through the first portion of the at least one fuel injection hole has favorable flow characteristics. In addition, the cavitation tendency of the fuel flowing through the at least one fuel injection hole is reduced.

[0046] Optionally, a wall surface of the nozzle extends linearly from the inlet opening to the outlet opening of the at least one fuel injection hole, wherein the wall surface forms the at least one fuel injection hole boundary surface. This provides conditions for ensuring that the fuel flowing through the at least one fuel injection hole has further favorable flow characteristics, while also providing conditions for ensuring that there is a smaller inflow angle at the edge of the inlet opening. In addition, the cavitation tendency of the fuel flowing through the at least one fuel injection hole is reduced. Furthermore, the at least one fuel injection hole can be provided in a simpler and more cost-effective manner.

[0047] Optionally, the at least one fuel injection hole is arranged on the nozzle and is provided by laser machining, which is also called laser beam machining (LBM) and sometimes laser drilling machining (LDM).

[0048] According to a second aspect of the present invention, the above object can be achieved by a fuel injector, which is configured to inject fuel into a combustion chamber of an internal combustion engine, wherein the fuel injector includes an injector body, a needle and a fuel injector nozzle. The fuel injector body forms a fuel chamber, and the needle is arranged in the injector body. The nozzle includes a nozzle head, and the nozzle head includes an inner surface and an outer surface. The inner surface is configured to form a limiting surface of an oil sac volume, and the outer surface is configured to be adjacent to the combustion chamber. The nozzle further includes a valve seat, and the valve seat is arranged to interact with the needle to open and close the fluid connection between the oil sac volume and the fuel chamber of the fuel injector. The nozzle further includes a plurality of fuel injection holes, each of which forms an inlet opening on the inner surface of the nozzle head and an outlet opening on the outer surface of the nozzle head. At least one of the plurality of fuel injection holes has a geometric center line, and the geometric center line is in a curved state along at least a first portion of the at least one fuel injection hole.

[0049] Since at least one of the fuel injection holes has a geometric center line, and the geometric center line is curved along at least the first portion of the at least one fuel injection hole, conditions are provided to ensure that the fuel flowing through the at least one fuel injection hole of the fuel injector has favorable flow characteristics.

[0050] Furthermore, since the geometric center line is curved along the at least first portion of the at least one fuel injection hole, a condition is provided to ensure that a reduced inflow angle exists at the edge of the inlet opening on the inner surface of the nozzle head. The reduced inflow angle at the edge of the inlet opening can reduce the tendency of cavitation at the edge of the inlet opening, and thus can reduce the possibility of material corrosion around the inlet opening on the inner surface of the fuel injector nozzle head. Therefore, the provision of the fuel injector provides conditions for improving durability and reliability.

[0051] Therefore, the provision of a fuel injector can overcome or at least alleviate at least some of the above problems and disadvantages. Thus, the above objectives are achieved.

[0052] According to a third aspect of the present invention, the above object can be achieved by an internal combustion engine. According to some embodiments of the present disclosure, the internal combustion engine includes a fuel injector, wherein the fuel injector is configured to inject fuel into a combustion chamber of the internal combustion engine. Since according to some embodiments, the internal combustion engine includes a fuel injector, providing an internal combustion engine can overcome or at least alleviate at least some of the above problems and disadvantages. Thus, the above object is achieved.

[0053] According to a fourth aspect of the present invention, the above object can be achieved by a vehicle. According to some embodiments of the present disclosure, the vehicle includes an internal combustion engine. Since according to some embodiments, the vehicle includes an internal combustion engine, providing a vehicle can overcome or at least alleviate at least some of the above problems and disadvantages. Thus, the above object is achieved.

[0054] Further features and advantages of the present invention will become apparent from a study of the appended claims and the following drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Various aspects of the present invention, including its particular features and advantages, may be more readily appreciated in conjunction with the following drawings and the exemplary embodiments discussed therein, in which:

[0056] Figure 1 schematically illustrates a vehicle according to certain embodiments;

[0057] Figure 2 Schematically shows Figure 1 An internal combustion engine of the vehicle shown in;

[0058] Figure 3 Shows Figure 2 A cross section of a fuel injector of the internal combustion engine shown;

[0059] Figure 4 Shows Figure 3 A cross section of a nozzle tip of a fuel injector nozzle shown in;

[0060] Figure 5 Schematically shows Figure 3 and Figure 4 The fuel injection holes of the nozzle shown in FIG.

[0061] Figure 6 Schematically shows Figure 3-Figure 5 An outlet opening of a fuel injection hole of the nozzle shown in FIG.

[0062] Figure 7 Schematically shows Figure 3-Figure 6 an inlet opening of a fuel injection hole of the nozzle shown in;

[0063] Figure 8 Shows Figure 3-Figure 7The elliptical cross section of the inlet portion of the fuel injection hole of the nozzle shown in FIG.

[0064] Fig. 9 Schematically shows Figure 3-Figure 8 A portion of the inner surface of the nozzle tip is shown in FIG. DETAILED DESCRIPTION

[0065] The various aspects of the present invention are described more fully below. The same numbers throughout the text refer to the same elements. For the sake of brevity and / or clarity, well-known functions or structures are not described in detail.

[0066] Figure 1 A vehicle 2 according to some embodiments is schematically shown. According to the illustrated embodiment, the vehicle 2 is a truck, i.e., a heavy vehicle. According to further embodiments, the vehicle 2 may be another type of heavy or lighter manned or unmanned land or water-based propulsion vehicle, such as a truck, bus, construction vehicle, tractor, car, ship, boat, etc.

[0067] The vehicle 2 includes an internal combustion engine 40. According to the illustrated embodiment, the internal combustion engine 40 is configured to provide power to the vehicle 2 via wheels 57 of the vehicle 2.

[0068] Figure 2 Schematically shows Figure 1 The internal combustion engine 40 of the vehicle 2 is shown. For the sake of brevity and clarity, the internal combustion engine 40 is referred to as the "combustion engine 40" or simply the "engine 40" in some places in this document. Figure 1 and Figure 2 .

[0069] In addition to the internal combustion engine 40 that provides power to the vehicle 2, the vehicle 2 may include one or more electric propulsion motors, and therefore, in addition to the internal combustion engine 40, the vehicle 2 also includes a so-called hybrid electric transmission system, which also includes one or more electric propulsion motors that provide power to the vehicle 2.

[0070] According to the illustrated embodiment, the internal combustion engine 40 includes six cylinders 20 arranged in a row. Therefore, the internal combustion engine 40 in the illustrated embodiment may be referred to as an "inline six-cylinder engine." However, according to further embodiments, the internal combustion engine 40 may include a different number of cylinders 20. In addition, the cylinders 20 of the internal combustion engine 40 may be arranged in a configuration other than one row, such as two or more rows.

[0071] According to the embodiment of this article, the internal combustion engine 40 is a four-stroke internal combustion engine. In addition, according to the illustrated embodiment, the internal combustion engine 40 is a diesel engine, i.e., a compression ignition engine. Therefore, the internal combustion engine 40 can be a compression ignition engine configured to run using a diesel or diesel-like fuel (such as biodiesel, diesel from biomass to liquid (BTL), diesel from gas to liquid (GTL)). Diesel-like fuels, such as biodiesel, can be obtained from renewable sources such as vegetable oils, and vegetable oils mainly include fatty acid methyl esters (FAME). Diesel-like fuels can be produced using various types of oils, such as rapeseed oil (rapeseed methyl ester, RME) and soybean oil (soybean methyl ester, SME).

[0072] According to further embodiments, the internal combustion engine 40 can be an Otto engine with a spark ignition device, wherein the Otto engine can be configured to use gasoline, alcohol, volatile fuel or a combination thereof. Alcohol, such as ethanol, can be obtained from renewable biomass. According to certain embodiments, the internal combustion engine 40 described herein can be arranged to provide power for another type of equipment, system or unit other than a vehicle (such as an electric generator, a ship, a vessel, etc.).

[0073] Each cylinder 20 of the internal combustion engine 40 includes a piston connected to a crankshaft of the internal combustion engine 40, and the piston is configured to reciprocate within the cylinder when the crankshaft rotates. A combustion chamber 42 is formed between the piston top and the cylinder wall of the cylinder 20 of the internal combustion engine 40.

[0074] The internal combustion engine 40 includes a plurality of fuel injectors 1, wherein each fuel injector 1 is configured to inject fuel into a combustion chamber 42 of the internal combustion engine 40. In other words, according to the illustrated embodiment, the internal combustion engine 40 includes the same number of fuel injectors 1 as the number of cylinders 20. Furthermore, according to the illustrated embodiment, each fuel injector 1 is configured to inject fuel directly into the combustion chamber 42 of the internal combustion engine 40.

[0075] Figure 3 Shows Figure 2 The cross section of the fuel injector 1 of the internal combustion engine 40 is shown. Figure 1-Figure 3 As described above, the fuel injector 1 is configured to inject fuel into the combustion chamber 42 of the internal combustion engine 40, such as Figure 1 and Figure 2 The combustion chamber 42 of the internal combustion engine 40 shown in FIG. 1 is injected with fuel. Figure 3 A combustion chamber 42 is also schematically shown.

[0076] The fuel injector 1 includes a fuel injector nozzle 9. The fuel injector nozzle 9 includes a nozzle head 9' disposed at a distal end of the fuel injector 1. The nozzle head 9' of the nozzle head is configured to protrude into a combustion chamber 42 of an internal combustion engine. As further explained herein, the fuel injector nozzle 9 of the fuel injector 1 is configured to inject fuel directly into the combustion chamber 42. For the sake of brevity and clarity, the fuel injector nozzle 9 is referred to as "nozzle 9" in some places herein.

[0077] The fuel injector 1 includes an injector body 10 and a needle 15. The needle 15 is arranged in the injector body 10. The nozzle 9 is connected to the injector body 10 through a sleeve device 51. The fuel injector 1 further includes a fuel chamber 13 formed in the injector body 10. The fuel injector 1 includes a fuel supply port 17 fluidly connected to the fuel chamber 13. The fuel supply port 17 is configured to be connected to a high-pressure fuel supply pipeline. That is, the internal combustion engine 40 includes the fuel injector 1 and may also include a fuel supply system, and the fuel supply system is configured to supply high-pressure fuel to each fuel supply port 17 of the fuel injector 1 configured on the internal combustion engine 40.

[0078] The fuel supply system may be a so-called common rail system. The fuel supply system may be configured to supply fuel at a pressure of 300 bar or above 1500 bar to each fuel supply port 17 of the fuel injector 1 arranged on the internal combustion engine 40 .

[0079] The nozzle 9 comprises a valve seat 12. As further explained below, the needle 15 is configured to interact with the valve seat 12 of the nozzle 9 to open and close a fluid connection between a fuel chamber 13 of the fuel injector 1 and a bladder volume.

[0080] Figure 4 Shows Figure 3 The cross section of the nozzle head 9' of the nozzle 9 on the fuel injector 1 is shown. Figure 4 You can also see Figure 3 A portion of the needle 15 and a portion of the sleeve device 51 of the fuel injector 1 are shown in FIG.

[0081] The nozzle head 9' comprises an inner surface 39 and an outer surface 41. The outer surface 41 of the nozzle head 9' is configured to be adjacent to the combustion chamber 42, and when the nozzle head 9' protrudes into the combustion chamber 42, it forms a bounding surface of the combustion chamber 42. In other words, the outer surface 41 of the nozzle head 9' is configured to face the combustion chamber 42. Figure 4 The combustion chamber 42 is also schematically shown. Figure 1-Figure 4 .

[0082] The inner surface 39 of the nozzle head 9' is configured to face the needle tip 55 of the needle 15, and is also configured to face the fuel chamber 13 of the fuel injector 1. The nozzle 9 further includes the valve seat 12 mentioned above. According to the embodiment shown, the valve seat 12 is a part of the inner surface 39 of the nozzle head 9'. In addition, the fuel injector 1 further includes the oil sac volume 19 mentioned above.

[0083] The nozzle 9 comprises a plurality of fuel injection holes 11, each of which forms an inlet opening 31 at the inner surface 39 of the nozzle head 9' and an outlet opening 32 at the outer surface 41 of the nozzle head 9'. Thus, when the fuel injector 1 is arranged in an internal combustion engine 40, the oil bladder volume 19 is fluidically connected to the combustion chamber 42 via the plurality of fuel injection holes 11.

[0084] The oil pocket volume 19 can be defined as the volume formed between the inlet opening 31 of the inner surface 39 of the nozzle tip 9' on the fuel injector 1 and the valve seat 12. Figure 4 As shown, the oil pocket volume 19 is bounded by the inner surface 39 of the nozzle head 9 ′ and the outer surface of the needle tip 55 .

[0085] The needle tip 55 of the needle 15 is configured to interact with the valve seat 12 of the nozzle 9 to open and close the fluid connection between the fuel chamber 13 and the oil bladder volume 19. More specifically, the needle 15 is configured to move along a movement axis mx in a first direction d1 and a second direction d2 to open and close the fluid connection between the oil bladder volume 19 and the fuel chamber 13 on the fuel injector 1. The movement axis mx of the needle 15 coincides with a geometric center axis of the needle 15 and a geometric center axis of the nozzle 9.

[0086] exist Figure 3 and Figure 4 In the embodiment, the first direction d1 constitutes the direction in which the needle 15 gradually moves away from the valve seat 12 toward the open position, in which the fluid connection between the oil sac volume 19 and the fuel chamber 13 of the fuel injector 1 is opened. Figure 3 and Figure 4 In the embodiment, the second direction d2 constitutes the direction in which the needle 15 moves toward the valve seat 12 of the nozzle 9 to a closed position, in which the fluid connection between the oil sac volume 19 on the fuel injector 1 and the fuel chamber 13 is closed, and the closing is achieved by the needle tip 55 abutting against the valve seat 12. Figure 3 and Figure 4 In the embodiment shown in FIG. 1 , the needle 15 is in the closed position.

[0087] Thus, according to the illustrated embodiment, the needle 15 moves from the closed position along the first direction d1 toward the open position, and from the open position along the second direction d2 toward the closed position, as shown in FIG. Figure 3 and Figure 4 As shown. Figure 3 As shown, the fuel injector 1 includes a spring member 14, which is configured to bias the needle member 15 to a closed position, that is, the spring member 14 is configured to move along Figure 3 The direction d2 shown biases the needle 15 .

[0088] The fuel injector 1 comprises a control valve device 3. As further described herein, the control valve device 3 is configured to control the movement of a needle 15 between an open position and a closed position. The movement of the needle 15 is achieved by hydraulic pressure. The hydraulic pressure is the hydraulic pressure in the control volume 13' of the fuel chamber 13.

[0089] The control valve device 3 comprises a control valve 4. The control valve 4 is fluidically connected to a control volume 13' of the fuel chamber 13 via a passage 18. The control volume 13' of the fuel chamber 13 is delimited by a top surface 15' of the needle 15. The control volume 13' is fluidically connected to the rest of the fuel chamber 13 and thus also to the fuel supply port 17 via a narrow flow-restricting passage.

[0090] According to the illustrated embodiment, the control valve 4 comprises a ball valve, which is configured to abut against the control valve seat 4' when the valve is closed. Figure 3 shown.

[0091] The control valve device 3 comprises an armature assembly 6 , which is operatively connected to the control valve 4 via a valve control part 6 ′ thereof.

[0092] More specifically, the armature assembly 6 includes an armature unit 36, a plunger 16, a spring 8 and a retainer 38. The plunger 16 is movably arranged in the armature unit 36. However, the plunger 16 includes a plunger top stop 16', which is configured to abut against an armature top stop 36' of the armature unit 36. The plunger 16 is biased toward the armature unit 36 ​​and the retainer 38 along the second direction d2 by the spring 8. According to the illustrated embodiment, the spring 8 is a coil spring. The contact of the plunger top stop 16' with the armature top stop 36' forces the armature unit 36 ​​to move toward the retainer 38 along the second direction d2.

[0093] The respective ends of the plunger 16 and the armature unit 36 ​​abut against the retainer 38. The retainer 38 abuts against the ball valve of the control valve 4. Therefore, due to these features, the spring 8 can also bias the retainer 38 toward the control valve 4 in the second direction d2, so that the ball valve of the control valve 4 can abut against the control valve seat 4'. The control valve device 3 includes a second spring member 28, which is configured to bias the armature unit 36 ​​along the first direction d1 to make it away from the valve seat 4'.

[0094] However, the biasing force of the second spring member 28 is lower than the biasing force of the spring 8. In other words, due to these features, the spring 8 is configured to force the armature assembly 6, that is, to apply a biasing force to the armature assembly 6, so that it is biased toward the closed position. Figure 3 As shown, according to the illustrated embodiment, the spring 8 is configured to apply a biasing force to the armature assembly 6 by applying a separation force at the first top stop 61 and the second top stop 62. The respective ends of the piston 16 and the armature unit 36 ​​are collectively referred to herein as the valve control portion 6' of the armature assembly 6.

[0095] The control valve device 3 includes an armature actuator 7. As further described below, the armature actuator 7 is configured to move the armature assembly 6 from a closed position to an open position to open the control valve 4, so that the needle 15 is lifted off the valve seat 12 under the action of hydraulic pressure. The hydraulic pressure is achieved by supplying fuel to the fuel chamber 13 through the fuel supply port 17 of the fuel injector 1.

[0096] According to the illustrated embodiment, the armature actuator 7 is configured to move the armature assembly 6 from the closed position to the open position. The movement is achieved by moving the armature unit 36 ​​along the first direction d1 away from the control valve 4 when the armature actuator 7 is activated. Due to the abutment between the plunger top stop 16' and the armature top stop 36', when the armature actuator 7 is activated, the plunger 16 also moves along the first direction d1, gradually away from the control valve 4.

[0097] As described above, the control volume 13' of the fuel chamber 13 is fluidly connected to the rest of the fuel chamber 13 via a narrow flow restriction passage, and thus to the fuel supply port 17. Therefore, when the control valve 4 is closed and in steady-state conditions, the fuel pressure in the control volume 13' of the fuel chamber 13 corresponds approximately to the fuel pressure in the rest of the fuel chamber 13. For example, if a fuel pressure of approximately 1500 bar is supplied to the fuel supply port 17 and the control valve 4 is in the closed state, the fuel pressure in the control volume 13' of the fuel chamber 13 will rise to 1500 bar after a short period of time. This is because the control volume 13' of the fuel chamber 13 is fluidly connected to the rest of the fuel chamber 13 via a narrow flow restriction passage.

[0098] However, when the armature actuator 7 is activated and the valve control part 6' of the armature assembly 6 moves along the first direction d1 and gradually moves away from the retainer 38, the ball valve of the control valve 4 can move along the first direction d1 and gradually move away from the control valve seat 4'. Therefore, when the valve control part 6' of the armature assembly 6 gradually moves away from the control valve seat 4' along the first direction d1, the high pressure of the fuel in the channel 18 forces the ball valve 4 and the retainer 38 to move along the first direction and gradually move away from the control valve seat 4', wherein the channel 18 is connected to the control valve 4.

[0099] In this way, the control valve 4 is opened, allowing the fuel to flow out of the control volume 13', through the passage 18, the control valve 4, and into the exhaust passage 44 of the fuel injector 1, thereby reducing the fuel pressure in the control volume 13'. Since the flow restriction passage connecting the control volume 13' to the rest of the fuel chamber 13 is very narrow, the fuel pressure in the control volume 13' is lower than the fuel pressure in the rest of the fuel chamber 13. Therefore, when the hydraulic pressure of the fuel in the fuel chamber 13 acts on the needle 15, the needle 15 can be lifted off the valve seat 12. In this way, the fuel is allowed to flow out of the fuel chamber 13, through the sac volume 19 and the plurality of fuel injection holes 11 on the fuel injector 1, and into the combustion chamber 42.

[0100] Lifting the needle 15 off the valve seat 12 means moving the needle 15 in the first direction d1, gradually away from the valve seat 12. When the needle 15 is lifted off the valve seat 12, the spring 14 is compressed. Similarly, as described above, when the armature actuator 7 is moved to the open position, the spring 8 of the control valve device 3 is compressed.

[0101] When the armature actuator 7 is not activated, the biasing force of the spring 8 moves the armature assembly 6 toward the closed position, that is, the valve control portion 6' of the armature assembly 6 moves along the second direction d2 toward the retainer 38. Therefore, the retainer 38 moves along the second direction d2 toward the ball valve of the control valve 4, and further, this movement moves the ball valve of the control valve 4 toward the control valve seat 4'. When the ball valve of the control valve 4 reaches the control valve seat 4' and is pressed against the control valve seat 4', the control valve 4 is closed, thereby preventing the fuel from further flowing from the control volume 13' through the control valve 4 to the exhaust passage 44.

[0102] In this way, the fuel pressure in the control volume 13' rises and, together with the biasing force of the spring member 14, forces the needle member 15 to move toward the valve seat 12, thereby closing the fluid connection between the fuel chamber 13 and the oil sac volume 19, thereby preventing the fuel from further flowing into the combustion chamber 42 through the multiple fuel injection holes 11 of the fuel injector 1.

[0103] According to the illustrated embodiment, the armature actuator 7 includes an electromagnet 7', which is configured to generate a magnetic field to move the armature assembly 6 from the closed position toward the open position. The electromagnet 7' includes a coil winding, which is connected to a pair of electrical connectors 46 and 46' of the fuel injector 1. According to the illustrated embodiment, the armature actuator 7 can be activated after power is supplied. The current required for power supply comes from the coil winding of the electromagnet 7'. After the electromagnet 7' is activated, the magnetic interaction between the coil winding of the electromagnet 7' and the metal parts of the armature unit 36 ​​can drive the armature unit 36 ​​to move.

[0104] As described above, the nozzle 9 of the fuel injector 1 includes a plurality of fuel injection holes 11, each of which forms an inlet opening 31 at the inner surface 39 of the nozzle head 9' and an outlet opening 32 at the outer surface 41 of the nozzle head 9'. Figure 3 and Figure 4 As shown, for the sake of simplicity and clarity, only one fuel injection hole 11 is shown in the figure. However, as further described below, the nozzle 9 of the fuel injector 1 may include a plurality of fuel injection holes 11.

[0105] According to an embodiment of the present invention, at least one fuel injection hole 11 of the plurality of fuel injection holes 11 has a geometric center line, and the geometric center line is curved along at least a first portion of the at least one fuel injection hole 11. Each fuel injection hole 11 of the plurality of fuel injection holes 11 may include a geometric center line. The geometric center line is curved along at least a first portion of the at least one fuel injection hole 11. In addition, each fuel injection hole 11 of the plurality of fuel injection holes 11 may have the same design and features. However, for the sake of brevity and clarity, when referring to one fuel injection hole 11 of the plurality of fuel injection holes 11 below, it is referred to as "fuel injection hole 11".

[0106] Figure 5 Schematically shows Figure 3 and Figure 4 The fuel injection hole 11 of the nozzle 9 of the fuel injector 1 is shown. If there is no other explanation below, please also refer to Figure 1-Figure 5 The fuel injection hole 11 extends from an inlet opening 31 to an outlet opening 32, wherein the inlet opening 31 is arranged at the inner surface 39 of the nozzle head 9' and the outlet opening 32 is arranged at the outer surface 41 of the nozzle head 9'. Therefore, the inlet opening 31 is arranged adjacent to the oil sac volume 19, and the outlet opening 32 is arranged adjacent to the combustion chamber 42, so that the fuel can flow out of the oil sac volume 19, through the fuel injection hole 11, into the inlet opening 31, and then into the combustion chamber 42 through the outlet opening 32.

[0107] The fuel injection hole 11 is formed by the boundary surface of the nozzle head 9' on the nozzle 9. The inlet opening 31 may also be referred to as "the inflow opening of the fuel injection hole 11", and similarly, the outlet opening 32 may also be referred to as "the outflow opening of the fuel injection hole 11".

[0108] like Figure 5It is clearly shown that the fuel injection hole 11 has a geometric center line c1. The geometric center line c1 is curved along the first portion p1 of the fuel injection hole 11. The term "geometric center line" c1 used herein refers to a line extending through the geometric center of the fuel injection hole 11. The geometric center refers to a center from which the distance to the defining surface of the fuel injection hole 11 (i.e., the distance to the wall of the nozzle 9 in the fuel injection hole 11) is the largest in all radial directions.

[0109] According to the embodiment shown, the first portion p1 of the fuel injection hole 11 includes the inlet opening 31 of the fuel injection hole 11 and the inlet portion 31' of the fuel injection hole 11. In addition, according to the embodiment shown, the entire first portion p1 of the fuel injection hole 11 has a curved geometric center line c1. The inlet portion 31' of the fuel injection hole 11 can be defined as the first 10% of the extension of the fuel injection hole 11, and the length corresponding to the first 10% is the distance from the inlet opening 31 to the outlet opening 32 measured along the direction d1'.

[0110] According to the illustrated embodiment, the length L1 of the first portion p1 of the fuel injection hole 11 constitutes approximately 88% of the total length L of the fuel injection hole 11, and the length that accounts for 88% of the total length is the length from the inlet opening 31 to the outlet opening 32 measured along the d1' direction. According to further embodiments, as described herein, the length L1 of the first portion p1 of the fuel injection hole 11 may constitute at least 30%, or at least 60%, of the total length L of the fuel injection hole 11. The length corresponding to the at least 30%, or at least 60%, is the distance measured from the inlet opening 31 to the outlet opening 32.

[0111] As further described herein, since the fuel injection hole 11 has a geometric center line c1, and the geometric center line c1 is curved along the first portion p1 of the fuel injection hole 11, conditions are provided to ensure that the fuel flowing through the fuel injection hole 11 has favorable flow characteristics.

[0112] In addition, since the geometric center line c1 is curved along the first portion p1 of the fuel injection hole 11, a condition is provided to ensure that a reduced inflow angle a31 exists at the edge 39' of the inlet opening 31, wherein the edge 39' of the inlet opening 31 is located at the inner surface 39 of the nozzle head 9'. The inner surface 39 of the nozzle head 9' is as shown in FIG. Figure 4 and Figure 5As shown. The reduced inflow angle a31 at the edge 39' of the inlet opening 31 can reduce the cavitation tendency of the fuel flowing around the edge 39' of the inlet opening 31, thereby reducing the corrosion of the material around the inlet opening 31 of the inner surface 39 of the nozzle head 9' of the nozzle 9. Therefore, a fuel injector nozzle 9 is provided to provide conditions for improving durability and reliability.

[0113] According to the illustrated embodiment, the geometric center line c1 is continuously curved along the first portion p1 of the fuel injection hole 11. Figure 5 It is clearly shown that the radius of curvature r1 of the geometric center line c1 increases when viewed from the inlet opening 31 along the direction d1' toward the outlet opening 32. The fact that the radius of curvature r1 of the geometric center line c1 increases when viewed from the inlet opening 31 along the direction d1' toward the outlet opening 32 means that the curvature of the geometric center line c1 decreases when viewed from the inlet opening 31 along the direction d1' toward the outlet opening 32.

[0114] In addition, if Figure 5 It is clearly shown that the curvature radius r1 increases continuously along the entire first portion p1 of the fuel injection hole 11, as seen from the inlet opening 31 along the direction d1' toward the outlet opening 32. Due to these features, conditions are provided to ensure that the fuel flowing through the fuel injection hole 11 (i.e., the fuel flowing from the inlet opening 31 to the outlet opening 32) has favorable flow characteristics.

[0115] According to the illustrated embodiment, the fuel injection hole 11 has a geometric center line c2. The geometric center line c2 is in a straight line along a second portion p2 of the fuel injection hole 11. The second portion p2 of the fuel injection hole 11 includes an outlet portion 32' of the fuel injection hole 11. The outlet portion 32' of the fuel injection hole 11 can be defined as the last 10% of the extension of the fuel injection hole 11, and the length corresponding to the 10% is the length measured from the inlet opening 31 to the outlet opening 32 along the direction d1'.

[0116] like Figure 5 As shown, according to the embodiment shown, the length L1 of the first portion p1 of the fuel injection hole 11 is greater than the length of the second portion p2 of the fuel injection hole 11. In addition, according to the embodiment shown, the first portion p1 and the second portion p2 of the fuel injection hole 11 constitute the entire fuel injection hole 11. Therefore, according to the embodiment shown, the length L2 of the second portion p2 of the fuel injection hole 11 constitutes approximately 12% of the total length L of the fuel injection hole 11, the length being measured in the direction d1' from the inlet opening 31 toward the outlet 32.

[0117] As further described herein, according to the described embodiment, the second portion p2 of the fuel injection hole 11 has a circular cross section cs2, which is in a plane Pc2 that is perpendicular to a geometric centerline c2 of the second portion p2.

[0118] Figure 6 Schematically shows Figure 3-Figure 5 The outlet opening 32 of the fuel injection opening 11 of the injection nozzle 9 is shown. Figure 5 The viewing angle of the outlet opening 32 shown is similar to Figure 5 The direction of d1' is shown to be opposite.

[0119] like Figure 6 As shown, according to the embodiment shown, the outlet opening 32 is circular. Thus, by injecting fuel from the outlet opening 32 of the fuel injection hole 11, a symmetrical flame structure can be obtained in the combustion chamber. The feature that the outlet opening 32 is circular means that the outlet opening 32 has a circular shape on a plane, which is a plane perpendicular to the average flow direction of the fuel flowing out of the outlet opening 32. According to further embodiments, the outlet opening 32 can be other shapes besides circular.

[0120] Figure 6 The diameter d32 of the outlet opening 32 is shown. Figure 5 The diameter d32 of the outlet opening 32 is also shown. Figure 5 As shown, the total length L of the fuel injection hole 11 is about 5 times greater than the diameter d32 of the outlet opening 32. According to further embodiments, the total length L of the fuel injection hole 11 may be at least 3 times greater than the diameter d32 of the outlet opening 32, or at least 4 times greater.

[0121] Unless otherwise specified below, please also refer to Figure 1-Figure 6 Since the total length L of the fuel injection hole 11 greatly exceeds the diameter d32 of the outlet opening 32, it provides conditions for ensuring that the fuel flowing through the fuel injection hole 11 has further favorable flow characteristics. In addition, it provides conditions for ensuring that there is a small inflow angle a31 at the edge 39' of the inlet opening 31, while avoiding that the curvature radius r1 of the geometric center line c1 of the fuel injection hole 11 is too small.

[0122] Figure 7 Schematically illustrates Figure 3-Figure 6 The inlet opening 31 of the fuel injection hole 11 on the nozzle 9 is shown. Figure 7 The state of the inlet opening 31 is shown, that is, Figure 5 The state observed along the direction consistent with d1'. Figure 7As shown, according to the embodiment shown, the inlet opening 31 is elliptical. The feature that the inlet opening 31 is elliptical means that the inlet opening 31 has an elliptical shape in a plane. The plane is a plane perpendicular to the average inflow direction of the fuel into the inlet opening 31. As defined herein, the eccentricity of the ellipse is strictly greater than zero.

[0123] According to further embodiments, the inlet opening 31 may have a non-circular and non-elliptical shape, such as a teardrop shape, a partial rectangle or the like. Figure 7 The maximum diameter d31' and the minimum diameter d31 of the inlet opening 31 are shown. According to the embodiment shown, the minimum diameter d31 of the inlet opening 31 corresponds to Figure 6 The diameter d32 of the outlet opening 32 is shown. According to a further embodiment, the smallest diameter d31 of the inlet opening 31 may substantially correspond to the diameter d32 of the outlet opening 32, ie differ from the diameter d32 of the outlet opening 32 by less than 10%, or less than 7%.

[0124] Furthermore, according to the illustrated embodiment, the minimum diameter d31 of the inlet opening 31 is approximately 65% ​​of the maximum diameter d31' of the inlet opening 31. According to further embodiments, the minimum diameter d31 of the inlet opening 31 may be in the range of 30%-99% or in the range of 45%-85% of the maximum diameter d31' of the inlet opening 31. Furthermore, as described above, the inlet opening 31 may be a non-elliptical shape.

[0125] Please refer to the following instructions Figure 5 According to the embodiment shown, the first portion p1 of the fuel injection hole 11 has an elliptical cross section cs1 on a plane Pc1 perpendicular to the direction d1 ′ from the inlet opening 31 toward the outlet opening 32 .

[0126] Figure 8 Shows Figure 3-Figure 7 The elliptical cross section cs1 of the inlet portion 31' of the fuel injection hole 11 is shown. The elliptical cross section cs1 is cut from a plane perpendicular to the average flow direction of the fuel flowing through the inlet portion 31' of the fuel injection hole 11. The average flow direction of the fuel flowing through the inlet portion 31' of the fuel injection hole 11 is substantially the same as Figure 5 The directions d1 ′ shown coincide.

[0127] According to the embodiment shown, the eccentricity of the elliptical cross section cs1 at the inlet portion 31' of the fuel injection hole 11 is about 0.75. According to a further embodiment, the eccentricity of the elliptical cross section cs1 at the inlet portion 31' of the fuel injection hole 11 is greater than 0.3, or greater than 0.5.

[0128] Unless otherwise specified below, please also refer to Figure 1-Figure 8 According to the embodiment shown, the eccentricity of the elliptical cross section cs1 decreases as viewed from the inlet opening 31 along the direction d1' toward the outlet opening 32. In addition, according to the embodiment shown, the eccentricity of the elliptical cross section cs1 decreases continuously along the entire first portion p1 of the fuel injection hole 11 as viewed from the inlet opening 31 along the direction d1' toward the outlet opening 32. Figure 5 As shown, the eccentricity of the fuel injection hole 11 reaches zero at the boundary Bd between the first portion p1 and the second portion p2 of the fuel injection hole 11. In this way, it is ensured that the fuel flowing through the fuel injection hole 11 has favorable flow characteristics, and a smooth transition of the liquid flow can be provided, thereby forming a flow stability zone at the second portion p2 of the fuel injection hole 11.

[0129] Figure 8 The major axis A and the minor axis B of the elliptical cross section cs1 are shown. According to the illustrated embodiment, the eccentricity of the elliptical cross section cs1 decreases continuously along the first portion p1 of the fuel injection hole 11 as viewed from the inlet opening 31 along the direction d1' toward the outlet opening 32, because the major axis A of the elliptical cross section cs1 decreases continuously along the first portion p1 of the fuel injection hole 11 as viewed from the inlet opening 31 along the direction d1' toward the outlet opening 32.

[0130] The minor axis B remains constant throughout the first portion p1 of the fuel injection hole 11 as viewed from the inlet opening 31 along the direction d1' toward the outlet opening 32. As described above, the major axis A of the elliptical cross section cs1 decreases continuously along the first portion p1 of the fuel injection hole 11 as viewed from the inlet opening 31 along the direction d1' toward the outlet opening 32, and reaches a length corresponding to the minor axis B at the boundary Bd between the first portion p1 and the second portion p2 of the fuel injection hole 11.

[0131] Figure 8 The semi-major axis a and the semi-minor axis b of the elliptical cross section cs1 are shown. The length of the semi-major axis a is half the length of the major axis A. Likewise, the length of the semi-minor axis b is half the length of the minor axis B.

[0132] like Figure 4-Figure 8 As shown, a wall surface 29 of the nozzle 9 has a linear extension, which extends from the inlet opening 31 of the fuel injection hole 11 to the outlet opening 32. The wall surface 29 forms the delimiting surface 11' of the fuel injection hole 11.

[0133] As described above, the curved geometric center line c1 of the first portion p1 of the fuel injection hole 11 is caused by the following facts:

[0134] The first portion p1 of the fuel injection hole 11 has an elliptical cross section cs1 on a plane, the plane being perpendicular to the direction d1', the direction d1' being the direction from the inlet opening 31 toward the outlet opening 32;

[0135] · Viewed from the inlet opening 31 along the direction d1 ′ toward the outlet opening 32 , the eccentricity of the elliptical cross section cs1 decreases;

[0136] The eccentricity of the first portion p1 of the fuel injection hole 11 satisfies the following condition: the boundary surface 11 ′ of the fuel injection hole 11 has a linear extension, and the linear extension passes through the first portion p1 of the fuel injection hole 11 .

[0137] Furthermore, as described above, according to the illustrated embodiment, the inlet opening 31 of the fuel injection hole 11 has a larger effective cross-sectional area than the outlet opening 32. This provides a condition for ensuring that the fuel flowing through the fuel injection hole 11 has favorable flow characteristics. Furthermore, a condition is also provided for ensuring that a smaller inflow angle a31 exists at the edge 39' of the inlet opening 31.

[0138] Furthermore, as described above, according to the illustrated embodiment, the effective cross-sectional area of ​​the fuel injection hole 11 continuously decreases along the entire first portion p1 of the fuel injection hole 11 .

[0139] As described herein, according to some embodiments, the cross-section of the first portion p1 of the fuel injection hole 11 may have a shape other than an ellipse. However, in such embodiments, the inlet opening 31 of the fuel injection hole 11 may have a larger effective cross-sectional area than the outlet opening 32 of the fuel injection hole 11. Furthermore, in such embodiments, the effective cross-sectional area of ​​the fuel injection hole 11 may continuously decrease along the entire first portion p1 of the fuel injection hole 11.

[0140] Fig. 9 Schematically shows Figure 3-Figure 9 A portion of the inner surface 39 of the nozzle head 9' of the nozzle 9 is shown. Fig. 9 The state of the inner surface 39 shown is that Figure 3 and Figure 4 The state seen along the direction consistent with the moving axis mx of the needle-shaped member 15. Unless otherwise specified below, please also refer to Figure 1-Figure 9 .

[0141] exist Fig. 9In FIG. 1 , a plurality of inlet openings 31 of a plurality of fuel injection holes 11 of the nozzle 9 can be seen. Fig. 9 As shown, according to the illustrated embodiment, the nozzle 9 may have 12 fuel injection holes 11. According to further embodiments, the nozzle 9 may have other numbers of fuel injection holes 11, such as 1 to 45, or 6 to 30.

[0142] Each of the plurality of fuel injection holes 11 of the nozzle 9 may include the same Figure 3-Figure 8 The fuel injection hole 11 has the same layout, design and advantages as described above.

[0143] exist Fig. 9 In the figure, for the sake of simplicity and clarity, the main axis A of the elliptical cross section cs1 on four of the multiple fuel injection holes 11 is shown. According to the illustrated embodiment, the direction of the elliptical cross section cs1 of the fuel injection hole 11 satisfies the following condition, namely: the main axis A of each elliptical cross section cs1 is substantially parallel to the planes p0, p0', and the planes p0, p0' include the moving axis mx of the needle member 15. In other words, according to the illustrated embodiment, the arrangement of the fuel injection holes 11 satisfies the following condition: the direction of the elliptical cross section cs1 satisfies: the main axis A of the elliptical cross section cs1 is substantially parallel to the planes p0, p0', and the planes p0, p0' include the moving axis mx of the needle member 15. This applies to all multiple fuel injection holes 11 arranged according to the illustrated embodiment. However, for the sake of simplicity and clarity, Fig. 9 Only two planes p0, p0' containing the movement axis mx of the needle 15 are shown.

[0144] Since the direction of the elliptical cross section cs1 of the fuel injection hole 11 satisfies that the main axis A of each elliptical cross section cs1 is substantially parallel to the planes p0, p0' containing the moving axis mx of the needle member 15, conditions are provided to ensure that the distance D3 between the edges of the adjacent inlet openings 31 of the plurality of fuel injection holes 11 is increased. In this way, conditions are provided for obtaining a nozzle 9 with a small oil pocket volume and / or a plurality of fuel injection holes, while avoiding hole mixing due to corrosion of the material of the nozzle 9.

[0145] In addition, it is possible to ensure that the edge 39' of the inlet opening 31 of the fuel injection hole 11 is processed to a greater extent to remove sharp edges and eliminate the risk of hole mixing. The processing can further prevent the formation of cavitation and the resulting erosion damage to the material of the nozzle 9. The edge 39' of the inlet opening 31 of the fuel injection hole 11 can be processed by, for example, water erosion processing, also known as abrasive fluid processing.

[0146] As described herein, according to certain embodiments, the cross-section of the first portion p1 of the fuel injection hole 11 may have a shape other than an ellipse, and the inlet opening 31 of the fuel injection hole 11 may have a shape other than an ellipse. In such embodiments, the fuel injection holes 11 may be appropriately arranged to satisfy the following conditions: the maximum diameter measurement direction of the cross-section of the inlet portion 31' of each fuel injection hole 11 (measured on a plane perpendicular to the average flow direction through the fuel injection hole 11) is substantially parallel to the planes p0 and p0'. The planes p0 and p0' include the moving axis mx of the needle member 15. As described above, Fig. 9 In the exemplary embodiment shown in FIG. 4 , the measuring direction of the elliptical cross section cs1 coincides with the main axis A of the elliptical inlet opening 31 shown.

[0147] The above content should be understood as follows: it is only used to illustrate various exemplary embodiments, and the present invention is defined only by the attached independent claims. Those skilled in the art will appreciate that the exemplary embodiments can be modified and different features can be combined to create different embodiments than those described herein without departing from the scope defined by the attached claims.

[0148] According to the present disclosure, each of the plurality of fuel injection holes 11 of the nozzle 9 may be provided by a laser machining method, wherein laser machining is also referred to as laser beam machining (LBM) or laser drilling machining (LDM).

[0149] As described herein, the terms "include" or "comprising" are open-ended, including one or more of the described features, elements, steps, components or functions, but do not exclude the existence or addition of one or more other features, elements, steps, components, functions or combinations thereof.

[0150] As used herein, the term "substantially parallel" may include an angle between two objects being less than 10 degrees, or less than 7 degrees.

[0151] As used herein, the term "substantially corresponds to" may include a deviation of less than 10% between the aspects, objects, distances or measurements.

[0152] As used herein, the term "substantially coincident with" may include an angle between two objects being less than 10 degrees, or less than 7 degrees.

Claims

1. A fuel injector nozzle (9) configured to inject fuel into a combustion chamber (42) of an internal combustion engine (40), the nozzle (9) comprising: A nozzle head (9'), the nozzle head (9') comprising an inner surface (39) and an outer surface (41), the inner surface (39) being configured to form a bounding surface of the oil pocket volume (19), and the outer surface (41) being configured to be adjacent to the combustion chamber (42); a valve seat (12) arranged to interact with the needle (15) to open and close the fluid connection between the bladder volume (19) and the fuel chamber (13) of the fuel injector (1), the fuel injector (1) comprising the nozzle (9), and A plurality of fuel injection holes (11), each fuel injection hole (11) forming an inlet opening (31) at an inner surface (39) of the nozzle head (9') and an outlet opening (32) at an outer surface (41) of the nozzle head (9'); At least one of the plurality of fuel injection holes (11) has a geometric center line (c1), and the geometric center line (c1) is curved along at least a first portion (p1) of the at least one fuel injection hole (11). Wherein, when viewed from the inlet opening (31) along the direction d1' toward the outlet opening (32), the radius of curvature (r1) of the geometric center line (c1) increases, and The radius of curvature (r1) increases continuously along at least a first portion (p1) of at least one fuel injection hole (11), viewed from the inlet opening (31) along the direction d1' toward the outlet opening (32).

2. The nozzle (9) according to claim 1, wherein the geometric center line (c1) is continuously curved along a first portion (p1) of at least one fuel injection hole (11).

3. The nozzle (9) according to claim 1 or 2, wherein the first portion (p1) of the at least one fuel injection hole (11) comprises an inlet portion (31') of the at least one fuel injection hole (11).

4. A nozzle (9) according to any of the preceding claims, wherein the length (L1) of the first portion (p1) of at least one fuel injection hole (11) constitutes at least 30%, preferably at least 60%, of the total length (L) of the at least one fuel injection hole (11), the length being the length measured from the inlet opening (31) to the outlet opening (32).

5. A nozzle (9) according to any of the preceding claims, wherein the total length (L) of at least one fuel injection hole (11) is at least 3 times greater than the diameter (d32) of the outlet opening (32), or at least 4 times greater than the diameter (d32) of the outlet opening (32).

6. The nozzle (9) according to any of the preceding claims, wherein the inlet opening (31) is elliptical.

7. A nozzle (9) according to any of the preceding claims, wherein the first portion (p1) of at least one fuel injection hole (11) has an elliptical cross-section (cs1) in a plane (Pc1) which is perpendicular to a direction d1' which is the direction from the inlet opening (31) to the outlet opening (32).

8. The nozzle (9) according to claim 7, wherein: The eccentricity of the elliptical cross section (cs1) decreases when viewed from the inlet opening (31) along the direction d1' towards the outlet opening (32).

9. The nozzle (9) according to any of the preceding claims, wherein the effective cross-sectional area of ​​the inlet opening (31) of the at least one fuel injection hole (11) is greater than the effective cross-sectional area of ​​the outlet opening (32) of the at least one fuel injection hole (11).

10. The nozzle (9) according to any one of the preceding claims, wherein the effective cross-sectional area of ​​the at least one fuel injection hole (11) decreases continuously along the entire first portion (p1) of the at least one fuel injection hole (11).

11. A fuel injector (1) configured to inject fuel into a combustion chamber (42) of an internal combustion engine (40), the fuel injector (1) comprising: an injector body (10) forming a fuel chamber (13); a needle member (15) disposed in the injector body (10), and A nozzle (9) of an injector (1) according to any of the preceding claims; The needle (15) is configured to interact with the valve seat (12) of the nozzle (9) to open and close the fluid connection between the fuel chamber (13) and the oil sac volume (19).

12. An internal combustion engine (40), comprising the fuel injector (1) according to claim 11, wherein the fuel injector (1) is configured to inject fuel into a combustion chamber (42) of the internal combustion engine (40).

13. A vehicle (2) comprising the internal combustion engine (40) of claim 12.

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