A multi-hole fuel injector and an internal combustion engine

Abstract

This application discloses a multi-hole fuel injector and an internal combustion engine, relating to the field of internal combustion engine technology, which reduces the cross interference of adjacent fuel jets. The multi-hole fuel injector has elliptical nozzles, the major axis of which is parallel to the combustion chamber axis. The absolute values ​​of the deviations in the major and minor axes of any two elliptical nozzles do not exceed preset thresholds, and the elliptical nozzles are uniformly distributed circumferentially along the multi-hole fuel injector.

Description

Technical Field

[0001] This application relates to the field of internal combustion engine technology, and more particularly to a multi-hole fuel injector and an internal combustion engine. Background Technology

[0002] With the rapid development of new energy technologies, traditional internal combustion engines (such as diesel engines) are facing more stringent fuel consumption limits, emission regulations and reliability requirements. At the same time, it is necessary to further improve the space utilization rate of the combustion chamber and the uniformity of the combustible mixture distribution.

[0003] Internal combustion engines employ a combustion mode combining premixed combustion and diffusion combustion, with diffusion combustion being the dominant mode. Therefore, the uniformity of the combustible mixture distribution directly affects the engine's performance. In traditional internal combustion engine systems, multi-orifice injectors with circular nozzles have significant technical limitations: when the number of nozzles is large, the circumferential spacing between adjacent nozzles is small. After the fuel jets impact the piston throat and combustion chamber wall, adjacent fuel jets are prone to cross-interference in the piston circumference. In other words, when a multi-orifice injector with circular nozzles operates, multiple fuel jets are injected into the combustion chamber in a radial pattern. After the free injection phase, they impact the piston throat and combustion chamber wall, and their direction of motion changes from the combustion chamber axis to the combustion chamber radially, diffusing circumferentially along the wall. Under this motion law, when the number of nozzles is large, the circumferential spacing between adjacent nozzles will decrease accordingly. Therefore, the circumferential diffusion range after the impact of adjacent fuel jets is prone to overlap, forming cross-interference areas. Figure 1 This is a simulation diagram illustrating the distribution of the equivalence ratio of the combustible mixture in the combustion chamber when a traditional multi-hole injector is operating. (The equivalence ratio is a key parameter that measures the proportion of fuel and air mixed in a combustible mixture; a higher equivalence ratio means that more fuel is mixed into a unit mass of air.) Figure 1 The rectangle R12 encloses the intersection interference region of the adjacent first oil beam F1 and the second oil beam F2, and the rectangle R23 encloses the intersection interference region of the adjacent second oil beam F2 and the third oil beam F3.

[0004] This cross-interference can lead to excessively high concentrations of fuel jets in localized areas, which are difficult to diffuse. This not only causes an imbalance in the distribution of the combustible mixture in the combustion chamber but also significantly reduces the space utilization rate within the combustion chamber, ultimately becoming a key bottleneck restricting the improvement of internal combustion engine performance. Utility Model Content

[0005] In view of the above problems, this application provides a multi-hole fuel injector and an internal combustion engine to reduce cross-interference between adjacent fuel jets. The specific solution is as follows:

[0006] The first aspect of this application provides a multi-hole injector, wherein the nozzles of the multi-hole injector are all elliptical nozzles, the major axis of the elliptical nozzles is parallel to the axial direction of the combustion chamber, the absolute value of the deviation of the major axis length of any two elliptical nozzles and the absolute value of the deviation of the minor axis length do not exceed a preset threshold, and each elliptical nozzle is uniformly distributed along the circumference of the multi-hole injector.

[0007] In one possible implementation, the reference injector is an injector in which all nozzles are circular nozzles, the absolute value of the radii of any two circular nozzles does not exceed a preset threshold, and the circular nozzles are uniformly distributed along the circumference of the reference injector; the area of ​​any nozzle in the multi-hole injector is not more than the area of ​​any nozzle in the reference injector, and the number of nozzles in the multi-hole injector is equal to that in the reference injector.

[0008] In one possible implementation, the size of the elliptical nozzle satisfies 2b > a; where a is the major semi-axis of the elliptical nozzle and b is the minor semi-axis of the elliptical nozzle.

[0009] In one possible implementation, the multi-hole injector is a nine-hole injector.

[0010] A second aspect of this application provides an internal combustion engine, including: a multi-hole fuel injector as described in the first aspect or any implementation thereof.

[0011] In one possible implementation, the piston top surface of the internal combustion engine is provided with multiple rib-like protrusions, each rib-like protrusion extending from the center of the piston top surface to the edge of the piston top surface, and the rib-like protrusions are arranged radially and evenly at intervals in the circumferential direction of the piston; the projection of the central axis of each rib-like protrusion along its extension direction onto the piston top surface coincides with the perpendicular bisector of the projection of the line connecting the centers of two adjacent elliptical injection holes on the piston top surface.

[0012] In one possible implementation, the rib-like protrusion has a smooth, rounded shape that is narrower at the top and wider at the bottom and symmetrical from left to right along its cross-section perpendicular to its extension direction, and the bottom of the rib-like protrusion is smoothly connected to the top surface of the piston.

[0013] In one possible implementation, the left half of the cross-section is composed of an inclined straight line segment, a first arc segment connected to the top of the straight line segment, and a second arc segment connected to the bottom of the straight line segment; the first arc segment is externally tangent to the straight line segment, and the second arc segment is externally tangent to the straight line segment and the piston top surface.

[0014] In one possible implementation, the angle between the straight line segment and the horizontal plane perpendicular to the piston's central axis is α, satisfying: 75°>α>45°.

[0015] In one possible implementation, the internal combustion engine is a diesel engine.

[0016] By employing the above technical solution, the multi-hole injector provided in this application adopts an elliptical nozzle with its long axis parallel to the combustion chamber axis. Combined with the uniform circumferential distribution and consistent size design of each nozzle, the fuel combustion effect can be significantly optimized: the single jet of fuel exhibits the characteristics of "axial stretching and circumferential narrowing". With the uniform circumferential distribution of nozzles forming a consistent initial injection angle and consistent flow rate of each jet, it can not only avoid local dense jets, but also reduce the probability of overlap of adjacent jets in the circumferential direction of the combustion chamber by reducing the circumferential diffusion range of a single jet of fuel. This effectively suppresses the problems of excessive circumferential diffusion and cross interference that are prone to occur in traditional circular nozzle jets. Attached Figure Description

[0017] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.

[0018] Figure 1 A simulation diagram of the equivalence ratio distribution of the combustible mixture in the combustion chamber during the operation of a conventional multi-hole fuel injector, provided for existing technology.

[0019] Figure 2 A schematic diagram of a multi-hole injector for fuel injection is provided in an embodiment of this application;

[0020] Figure 3 A schematic diagram of the axial cross-section of the fuel jet patterns of different multi-hole injectors; wherein, Figure 3 (a) A schematic diagram of the axial cross-section of the spray jet pattern of a conventional multi-hole injector provided by the prior art; Figure 3 (b) A schematic axial cross-sectional view of the spray jet pattern of a multi-hole injector provided in an embodiment of this application;

[0021] Figure 4 This is a schematic cross-sectional view of the ribbed protrusions of an internal combustion engine piston provided in an embodiment of this application, perpendicular to its extension direction. Detailed Implementation

[0022] To address the problem of cross-interference of fuel jets in the combustion chamber in existing technologies, this application provides a multi-hole fuel injector to reduce interference between adjacent fuel jets, making the fuel-air mixture more uniform, improving combustion quality, and thus enhancing the performance of the internal combustion engine.

[0023] The following description, in conjunction with the accompanying drawings, describes a multi-hole fuel injector according to an embodiment of this application. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in this application are also applicable to similar technical problems.

[0024] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0025] See Figure 2 The multi-hole injector provided in this application has the following structural design: the nozzles 2 of the multi-hole injector 1 are all elliptical nozzles, the major axis of the elliptical nozzles is parallel to the axial direction of the combustion chamber, the absolute value of the deviation of the major axis length of any two elliptical nozzles and the absolute value of the deviation of the minor axis length do not exceed a preset threshold (that is, the size of each elliptical nozzle is basically the same), and each elliptical nozzle is evenly distributed along the circumference of the multi-hole injector 1 (that is, the distance between each two adjacent elliptical nozzles in the circumference of the multi-hole injector 1 is basically equal).

[0026] Specifically, the combustion chamber, as the core space of the internal combustion engine's combustion system, is enclosed by the bottom surface of the cylinder head, the cylinder wall, and the piston top surface 3 (where the piston top surface 3 forms the lower boundary of the combustion chamber). It is the dedicated site for fuel combustion reactions. When the internal combustion engine is working, the multi-hole injector precisely injects high-pressure fuel into the combustion chamber through multiple nozzles in the form of a fuel jet 4, which mixes with the air introduced through the intake system to form a combustible mixture. As the piston moves to top dead center, the volume of the combustion chamber continuously decreases due to the rise of the piston top surface 3, and the combustible mixture is compressed to a high-temperature and high-pressure state. At the end of the compression stroke, the combustible mixture is ignited and burns rapidly. The released heat energy pushes the piston downward, and then the reciprocating motion of the piston is converted into the rotational power of the crankshaft through the crankshaft connecting rod mechanism, completing one cycle of energy conversion.

[0027] The spatial distribution of fuel after it enters the combustion chamber directly affects the uniformity of the combustible mixture and the combustion efficiency. The nozzle design of traditional multi-hole injectors still has room for optimization in this aspect. Unlike traditional circular nozzle designs, the multi-hole injector provided in this application uses an elliptical nozzle with its major axis parallel to the combustion chamber axis (i.e., a vertically elongated elliptical nozzle). This geometric feature directly changes the spatial diffusion pattern of the fuel jet: after a single fuel jet is ejected through the elliptical nozzle, it exhibits an expanded axial distribution range and a reduced circumferential distribution range within the combustion chamber (i.e., the spatial distribution of a single fuel jet exhibits "axial stretching and circumferential narrowing"), laying a structural foundation for reducing interference between adjacent fuel jets.

[0028] The elliptical nozzles are evenly distributed circumferentially along the multi-hole injector, further optimizing the overall spatial arrangement of the fuel jet. The uniform circumferential spacing between the nozzles and the near-equal size of each nozzle result in consistent fuel jet flow rates, which, combined with the circumferential narrowing characteristic of a single fuel jet, creates a synergistic effect: on the one hand, the initial injection angle of adjacent fuel jets remains consistent due to the uniform distribution of nozzles circumferentially along the multi-hole injector, and the consistency of fuel jet flow rates prevents localized fuel jet congestion; on the other hand, the reduction in the circumferential diffusion range of a single fuel jet directly reduces the probability of overlap between adjacent fuel jets in the combustion chamber circumferentially, suppressing the cross-interference problem caused by excessive circumferential diffusion of the fuel jet during injection diffusion in traditional circular nozzles from the source.

[0029] In summary, the above-described structural design of the multi-hole injector provided in this application significantly enhances the formation and combustion of the combustible mixture. The increased axial penetration depth ensures more uniform fuel coverage of the entire combustion chamber, improving space utilization. The circumferential uniform distribution, the narrowing of the single fuel jet circumferentially, and the essentially equal size of each nozzle collectively prevent excessively high local fuel concentrations or obstructed diffusion, resulting in a more uniform distribution of the combustible mixture equivalence ratio within the combustion chamber. This uniform combustible mixture provides a prerequisite for efficient combustion, accelerating the combustion rate, improving heat release efficiency, thereby reducing fuel consumption and harmful emissions, while simultaneously enhancing the stability and reliability of the internal combustion engine's power output.

[0030] In one possible implementation, compared to a traditional multi-hole injector (i.e., a reference injector, where each nozzle is a circular nozzle, the absolute value of the radii of any two circular nozzles does not exceed a preset threshold, and the circular nozzles are uniformly distributed along the circumference of the reference injector), the area of ​​any nozzle in the multi-hole injector provided in this application embodiment deviates from the area of ​​any nozzle in the reference injector by an absolute value not exceeding a preset threshold (i.e., the areas are substantially equal), and the number of nozzles in the multi-hole injector is equal to that in the reference injector.

[0031] Specifically, fuel injection quantity is a core parameter of the internal combustion engine control system, directly affecting the air-fuel ratio, combustion pressure, and power output. Circular nozzles are the most widely used structure in internal combustion engines, and their matching relationship with engine operating conditions has been verified over a long period. This application's embodiments maintain a constant total fuel injection quantity by ensuring that the area and number of elliptical and circular nozzles are essentially the same. The core objective is to improve performance through nozzle shape optimization without altering the original fuel supply system of the internal combustion engine. Therefore, this application's embodiments can directly reuse traditional internal combustion engine hardware such as fuel pumps and pressure sensors, as well as mature control algorithms, ensuring that the newly designed multi-hole injector can seamlessly replace existing products and reduce the risk of technological iteration.

[0032] Figure 3(a) A schematic diagram of the axial cross-section of the spray jet pattern of a conventional multi-hole injector (reference injector) provided by the prior art, wherein the area of ​​the circular nozzle is πR², and R is the radius R of the circular nozzle. Figure 3 (b) is an axial cross-sectional schematic diagram of the fuel jet shape of the multi-hole injector provided in the embodiment of this application, where the area of ​​the elliptical nozzle is πab, a is the major semi-axis of the elliptical nozzle, and b is the minor semi-axis of the elliptical nozzle. Figure 3 (a) Improved to Figure 3 (b) illustrates a change in the shape of the nozzle, but not in the number of nozzles, their circumferential distribution, or their area (the area πab of an elliptical nozzle is approximately equal to the area πR² of a circular nozzle). Furthermore, when the number of nozzles in a multi-hole injector is large or in-cylinder fuel jet interference is severe, the axial distribution of the fuel jet in the combustion chamber can be made more elongated by increasing the long semi-axis a and decreasing the short semi-axis b. However, the parameter constraint 2b > a must be strictly followed. This constraint avoids the problem of a sudden reduction in effective flow area caused by excessively elongated elliptical nozzles, ensuring smooth fuel jet ejection. Figure 3 (a) and Figure 3 In (b), reference numeral 4 indicates the oil jet, and reference numeral 3 indicates the piston top surface.

[0033] In one possible implementation, the multi-hole injector structure constructed based on any of the aforementioned technical embodiments can preferentially adopt a nine-hole configuration (i.e., the injector's nozzle unit has nine independent nozzles evenly distributed circumferentially), forming a nine-hole injector. It should be clarified that the nine-hole configuration is merely a typical application form of this multi-hole injector, not the only limitation. The number of nozzles can be flexibly adjusted according to core parameters such as the internal combustion engine's displacement, combustion chamber volume, and fuel injection requirements, adapting to a wider range of power system scenarios.

[0034] As an extension of the above-mentioned multi-hole injector technology, this application further provides an internal combustion engine. The core feature of this internal combustion engine is that its fuel injection module integrates the multi-hole injector disclosed in any of the aforementioned embodiments (including core designs such as elliptical nozzle structure, nozzle size consistency control, and circumferential uniform distribution). Through the deep collaboration between the injector and the internal combustion engine combustion system, the comprehensive optimization of power performance, emission indicators and fuel economy is achieved.

[0035] In one possible implementation, the internal combustion engine based on any of the above embodiments still refers to... Figure 3(b) The piston top surface 3 of the internal combustion engine is provided with multiple rib-like protrusions 5. Each rib-like protrusion 5 extends from the center of the piston top surface to the edge of the piston top surface, and the rib-like protrusions 5 are arranged radially and evenly at intervals in the circumferential direction of the piston. The projection of the central axis of each rib-like protrusion along its extension direction onto the piston top surface coincides with the perpendicular bisector of the projection of the line connecting the centers of two adjacent elliptical nozzles on the multi-hole injector onto the piston top surface (i.e., the rib-like protrusion is precisely located in the middle region of adjacent fuel jets). Thus, the injection area of ​​one nozzle is formed between two adjacent rib-like protrusions. The rib-like protrusions are used to block the circumferential diffusion of the fuel jet, so that the main diffusion area of ​​each fuel jet is limited within the corresponding rib-like protrusion interval, further suppressing the cross-interference problem caused by excessive circumferential diffusion of adjacent fuel jets during the injection diffusion process. The multi-hole injector structure design provided in this application embodiment, combined with the rib-like protrusions on the piston top surface, physically blocks the circumferential diffusion of the fuel jet. This effectively reduces the circumferential interference between adjacent fuel jets after multiple fuel jets impact the piston, significantly improving the uniformity of fuel-air mixing and combustion quality, and optimizing the performance of the internal combustion engine.

[0036] In one possible implementation, based on the internal combustion engine provided in any of the above embodiments, such as Figure 4 As shown, the rib-like protrusion has a smooth, rounded shape with a narrow top and wide bottom, and is symmetrical (the right half of the profile is a complete mirror image of the left half of the profile) along its cross-section perpendicular to its extension direction (i.e., the section taken along the perpendicular direction of the extension direction of the rib-like protrusion). The cross-sectional profile forms a smooth curve without breaks or sharp edges, and the bottom of the rib-like protrusion smoothly transitions to the piston top surface. The technical effects of this structural feature are as follows: the symmetrical profile with a narrow top and wide bottom guides the airflow in the combustion chamber to form an orderly vortex along both sides of the protrusion. Combined with the smooth transition design between the bottom and the piston top surface, it effectively reduces airflow resistance and eliminates local turbulence zones, promoting rapid and homogeneous mixing of fuel and air. At the same time, the smooth, rounded shape without sharp edges optimizes the heat load distribution on the piston top surface, reduces the risk of heat stress concentration, and reduces thermal deformation caused by local high temperatures. In addition, the mechanical impact of airflow impact noise and combustion pressure fluctuations on the piston is weakened due to the smooth transition characteristics of the rib-like protrusion structure.

[0037] For example, the left half of the cross-section is composed of an inclined straight line segment L, a first arc segment R1 connected to the top of the straight line segment L, and a second arc segment R2 connected to the bottom of the straight line segment L; the first arc segment R1 is externally tangent to the straight line segment L, and the second arc segment R2 is externally tangent to the straight line segment L and the piston top surface. The conformal design of the rib-like protrusion can be achieved by changing the radius of the first arc segment, the radius of the second arc segment, the angle α between the straight line segment and the horizontal plane perpendicular to the piston's central axis, and the maximum height h of the cross-sectional protrusion, to suit different combustion systems.

[0038] Specifically, the inclined straight segment L serves as the "main support segment" of the ribbed protrusion's side. Its inclination angle (the angle α between the straight segment and the horizontal plane perpendicular to the piston's central axis) directly determines the steepness of the protrusion's side, making it the core force-bearing unit that prevents the circumferential diffusion of the fuel jet. After the fuel jet impacts the piston top surface, most of the fuel flows upwards or downwards along the straight segment L—the upward-flowing fuel is guided to the upper part of the combustion chamber to mix with air, while the downward-flowing fuel slides along the straight segment L towards the piston top surface, preventing localized fuel accumulation. Simultaneously, the length of the straight segment L is directly related to the maximum height h of the protrusion, determining the "vertical coverage range" of the ribbed protrusion on the fuel jet.

[0039] The first arc segment R1 serves as the "top transition section" of the rib-like protrusion. One end of it is externally connected to the top of the straight segment L (i.e., the tangent direction of the arc at the point of tangency is completely consistent with the extension direction of the straight segment L), while the other end smoothly transitions to the top apex of the protrusion. The core purpose of this "external tangent design" is to eliminate the top sharp angle: if a right angle or acute angle is used at the top, it will cause the airflow in the cylinder to form a vortex dead zone (the airflow cannot smoothly bypass the protrusion), which not only increases the airflow resistance, but may also cause fuel to accumulate at the sharp angle, forming carbon deposits; while the arc transition of the first arc segment R1 allows the airflow to flow smoothly along the top of the protrusion, while reducing the concentration of thermal stress and preventing the piston from cracking due to local high temperature.

[0040] The second arc segment R2, serving as the "bottom connection segment" between the ribbed protrusion and the piston top surface, must simultaneously satisfy the dual constraints of being "tangent to the bottom end of the straight segment L" and "tangent to the piston top surface." Tangenting to the straight segment L ensures the continuity of the side profile, preventing rebound caused by abrupt changes in the step when the fuel jet flows along the straight segment L to the bottom; tangenting to the piston top surface achieves a "stress-free transition" between the protrusion and the piston base. The key functions of this design are: firstly, to guide the fuel flowing downwards along the straight segment L smoothly to the piston top surface, reducing atomization and breakage losses caused by fuel impact; and secondly, to prevent thermal fatigue caused by abrupt structural changes at the bottom connection point.

[0041] In addition, the angle α between the straight segment L and the horizontal plane perpendicular to the piston's central axis directly determines the circumferential constraint capability of the rib-like protrusion on the fuel jet and its adaptability to the in-cylinder airflow. Its value must be strictly limited within a specific range to balance the combustion system's "fuel jet control requirements" and "airflow organization requirements".

[0042] When α is too large, it affects the movement of the fuel jet along the piston circumference after impact and also hinders the movement of the in-cylinder swirl. Specifically, when α is too large, from the perspective of fuel jet movement characteristics, the "axial stretching-circumferential narrowing" type fuel jet ejected from the elliptical nozzle should achieve orderly flow along the ribbed side surface after impacting the piston top surface—that is, some fuel slides along the side towards the piston center area, and some diffuses upward with the airflow to the upper part of the combustion chamber. However, the excessively steep sidewall shape caused by excessively large α will prevent the fuel jet from flowing smoothly along the wall after impact, resulting in "rigid rebound": the rebounding fuel droplets are faster and move in a disordered direction. Some fuel droplets will cross adjacent injection areas to form interference, while others will accumulate near the sidewall to form a local fuel-rich area, directly aggravating incomplete combustion and particulate matter emissions. From the perspective of airflow organization, steep sidewalls will physically cut the intake vortex and compression vortex in the cylinder, causing the continuous vortex to break into multiple small-scale dead zones, increasing the turbulent kinetic energy loss rate, significantly reducing the fuel-air mixing efficiency, and thus leading to a decrease in combustion rate and power output.

[0043] When the value of α is too small, the core control function of the rib-like protrusion will fail. At this time, the sidewall has a gentle slope shape, the resistance to the circumferential diffusion of the oil jet is small, and the oil jet can easily cross the sidewall and enter the adjacent injection channel.

[0044] In one possible implementation, through multi-dimensional experimental verification of the combined oil jet control effect and airflow organization efficiency, the optimal working range of α was determined to be 75° > α > 45°.

[0045] In one possible implementation, based on any of the above embodiments, the internal combustion engine provided in this application is, for example, a diesel engine (i.e., a reciprocating piston internal combustion engine that uses compression ignition combustion). However, the application of this technical solution is not limited to the single type of diesel engine, but can be extended to other types of internal combustion engines according to the characteristics and performance requirements of the combustion system.

[0046] The above description of the disclosed embodiments enables those skilled in the art to clearly understand the technical solution architecture, core improvement logic, and implementation path of this utility model, and thus have the ability to implement or apply this utility model based on the description. Whether directly adopting the parameters of the typical embodiments disclosed in the text (such as nozzle size and protrusion angle) to adapt to specific scenarios, or making adaptive adjustments to the local structure (such as the number of nozzles and protrusion material) in combination with actual needs, the transformation and implementation of the technical solution can be completed based on the above description.

[0047] After studying the above embodiments, those skilled in the art can make various reasonable modifications to the embodiments based on their own technical experience and application scenario requirements. Such modifications are obvious to those skilled in the art. For example, for internal combustion engines of different displacements, the ratio of the long half-axis to the short half-axis of the nozzle, and the height and spacing of the ribbed protrusions can be adjusted while keeping the core design of "elliptical nozzle + ribbed protrusions" unchanged. For different operating temperature environments, the material used to manufacture the nozzle unit or piston protrusions can be replaced. For different fuel types, the flow area and surface roughness of the nozzle can be finely adjusted. These modifications do not depart from the general principles disclosed in this utility model, but rather are detailed optimizations of the technical solution, aiming to adapt to a wider range of application scenarios.

[0048] The general principles defined in this document are based on the logical framework of "solving the pain points of existing technologies through specific structural improvements" (such as optimizing the oil jet morphology through elliptical nozzles or constraining oil jet diffusion through ribbed protrusions), rather than being limited to the parameters or structural details of a specific embodiment. These general principles are universally applicable across scenarios and can be implemented in other types of technical solutions even outside the specific embodiments shown herein. Reasonable extensions of these general principles are also covered by the spirit of this invention.

[0049] It should be noted that the scope of protection of this utility model is not limited to the specific embodiments disclosed herein. The core of determining whether a technical solution falls within the scope of protection of this utility model lies in whether it follows the technical principles disclosed herein (such as solving specific technical pain points through structural optimization) and whether it possesses the same or similar novel features as this utility model (such as an innovative design that differs from traditional structures). Even if a technical solution differs from the embodiments described herein in specific structural parameters or assembly methods, as long as its technical concept and improvement logic are consistent with this utility model, it should be included in the scope of protection of this utility model.

[0050] Therefore, this utility model is not limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the technical principles and novel features disclosed herein. This definition of the scope provides clear guidance for improvements to the prior art and reserves reasonable space for subsequent innovations and expansions based on this utility model by those skilled in the art, thus contributing to the continuous progress of related technical fields, while protecting the legitimate rights and interests of the applicant and preventing the undue circumvention of core innovative achievements.

[0051] Furthermore, in defining the scope of protection of this utility model, the applicable logic and boundaries of the "doctrine of equivalence" must be fully considered. This principle is the core rule in the patent protection system that balances "innovation protection" and "technological fairness." Its core meaning is that for technical features that are explicitly disclosed in the specification and claims of this utility model, if they are "substantially identical" in terms of technical means, functional implementation, and effect achievement, and if such substitution relationship can be naturally associated with by a person skilled in the art without creative effort at the time of patent application, they should be legally recognized as "equivalent features" to the disclosed features of this utility model. The complete technical solution constructed by such equivalent features should also fall within the statutory protection scope of this utility model.

Claims

1. A multi-hole fuel injector, characterized in that, The nozzles of the multi-hole injector are all elliptical nozzles. The major axis of the elliptical nozzle is parallel to the axial direction of the combustion chamber. The absolute values ​​of the deviation of the major axis length and the absolute values ​​of the deviation of the minor axis length of any two elliptical nozzles do not exceed a preset threshold. Moreover, each elliptical nozzle is evenly distributed along the circumference of the multi-hole injector.

2. The multi-hole injector according to claim 1, characterized in that, The reference injector is an injector in which all nozzles are circular, the absolute value of the radius length deviation between any two circular nozzles does not exceed a preset threshold, and all circular nozzles are uniformly distributed along the circumference of the reference injector; the area of ​​any nozzle in the multi-hole injector is not more than the area of ​​any nozzle in the reference injector, and the number of nozzles in the multi-hole injector is equal to that in the reference injector.

3. The multi-hole injector according to claim 1 or 2, characterized in that, The dimensions of the elliptical nozzle satisfy 2b > a; where a is the major semi-axis of the elliptical nozzle and b is the minor semi-axis of the elliptical nozzle.

4. The multi-hole injector according to claim 1 or 2, characterized in that, The multi-hole injector is a nine-hole injector.

5. An internal combustion engine, characterized in that, include: The multi-hole injector according to any one of claims 1 to 4.

6. The internal combustion engine according to claim 5, characterized in that, The piston top surface of the internal combustion engine is provided with multiple rib-like protrusions. Each rib-like protrusion extends from the center of the piston top surface to the edge of the piston top surface, and the rib-like protrusions are arranged radially and evenly at intervals in the circumferential direction of the piston. The projection of the central axis of each rib-like protrusion along its extension direction onto the piston top surface coincides with the perpendicular bisector of the projection of the line connecting the centers of two adjacent elliptical injection holes on the multi-hole injector onto the piston top surface.

7. The internal combustion engine according to claim 6, characterized in that, The rib-like protrusion has a smooth, rounded shape that is narrower at the top and wider at the bottom and symmetrical from left to right along its cross-section perpendicular to its extension direction, and the bottom of the rib-like protrusion is smoothly connected to the top surface of the piston.

8. The internal combustion engine according to claim 7, characterized in that, The left half of the cross-section is composed of an inclined straight line segment, a first arc segment connected to the top of the straight line segment, and a second arc segment connected to the bottom of the straight line segment; the first arc segment is externally tangent to the straight line segment, and the second arc segment is externally tangent to the straight line segment and the top surface of the piston.

9. The internal combustion engine according to claim 8, characterized in that, The angle between the straight line segment and the horizontal plane perpendicular to the piston's central axis is α, and satisfies: 75°>α>45°.

10. The internal combustion engine according to claim 5, characterized in that, The internal combustion engine is a diesel engine.

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