CN106286057B

CN106286057B - Fuel injection nozzle

Info

Publication number: CN106286057B
Application number: CN201610470908.8A
Authority: CN
Inventors: 藤挂文裕; 芹泽一史; 宇都宫敦司; 桥本雄太
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2015-06-24
Filing date: 2016-06-24
Publication date: 2020-09-25
Anticipated expiration: 2036-06-24
Also published as: FR3042545B1; FR3042546A1; FR3042545A1; FR3042547A1; JP2017008861A; DE102016109765A1; FR3042546B1; CN106286057A; FR3042547B1; FR3038009A1; FR3038009B1

Abstract

The present invention relates to a fuel injection nozzle. It is known that: the displacement direction of the needle-shaped piece (2) is axial; the direction in which the needle (2) is displaced when fuel injection starts is the upper side; the central point of the spherical ball with the bag-shaped chamber (6) is the bag-shaped central point (P1); a line extending axially through the bag center point (P1) is the bag centerline (L1); and a straight line obtained by extending the center axis of the orifice (3) into the bag-like chamber (6) is an orifice extension line (L2), the orifice extension line (L2) being provided so as to intersect the bag center line (L1); and an actual intersection point (JP2) where the orifice extension line (L2) and the bag center line (L1) intersect with each other is disposed on the upper side of the bag center point (P1).

Description

Fuel injection nozzle

Technical Field

The present disclosure relates to a fuel injection nozzle that injects fuel.

Background

A conical insertion-type fuel injection nozzle is known in which a conical portion provided at an end of a needle overlaps a sac chamber of a nozzle body in an axial direction (see JP2010-174819 a).

In the description herein, for convenience of explanation, the direction in which the needle moves is referred to as an axial direction, the direction perpendicular to the axial direction is referred to as a vertical direction, the direction in which the needle moves when fuel injection is started is referred to as "up" (upward direction, upper side), and the direction in which the needle moves when fuel injection is stopped is referred to as "down" (downward direction, lower side). A center point of a sphere constituting the bag-like chamber is referred to as a bag center point, a straight line extending through the bag center point in the axial direction is referred to as a bag center line, and a straight line obtained by extending a center axis of the nozzle hole into the bag-like chamber is referred to as a nozzle hole extension line. The line obtained by projecting the nozzle hole extension line in the vertical direction is referred to as a projection line, and the angle from the lower side of the bag center line to the nozzle hole extension line is referred to as a spray angle. Obviously, for example, when the nozzle is installed, the up direction and the down direction used in the description herein are not limited to the vertical direction (top-bottom direction).

A conical insertion type fuel injection nozzle is provided in which a nozzle hole extension line passes through a bag center point. Specifically, the nozzle is provided such that the orifice extension line is at right angles to a tangent of a spherical surface defining the pocket chamber.

The problems with fuel injection nozzles are as follows. For example, depending on the structure of an engine including the fuel injection nozzle, the spray penetration force required of the fuel injection nozzle changes. In particular, according to diversification of engines, it has recently been required that a fuel injection nozzle has a small spray penetration force at a low lift time when the lift amount of a needle is small, and has a large spray penetration force at a high lift time when the lift amount of the needle is large. In one example, for example, an injection characteristic having low penetration may be required at a light load where the injection quantity is small to avoid a cooling loss of the injected fuel by cooling the wall surface of the combustion chamber, and an injection characteristic having high penetration may be required at a high load where the injection quantity is large to contribute to improvement of exhaust gas.

Alternatively, and in contrast to the above, the fuel injection nozzle may be required to achieve a large spray penetration at low lift times and a small spray penetration at high lift times.

However, the aforementioned conical insertion type fuel injection nozzle cannot satisfy the above-described need. The spray penetration force is a force that ejects the atomized fuel ejected through the ejection hole, and the atomized fuel can be ejected by increasing the spray penetration force.

Disclosure of Invention

The present disclosure addresses at least one of the above-mentioned problems. Accordingly, a first object of the present disclosure is to provide a conical insert type fuel injection nozzle having a small spray penetration force at a low lift time and a large spray penetration force at a high lift time. Further, a second object of the present disclosure is to provide a conical insertion type fuel injection nozzle having a large spray penetration force at a low lift time and a small spray penetration force at a high lift time.

To achieve the first object of the present disclosure, a fuel injection nozzle including a nozzle body and a needle is provided. The nozzle body includes a valve seat, a pocket chamber, and a nozzle hole. The valve seat is formed inside the nozzle body and has a conical surface shape. The sac-like chamber is formed inside the nozzle body, and has a spherical shape that fuses together the pressurized fuel passing through the inside of the valve seat. The pressurized fuel supplied into the sac chamber is injected outside the nozzle body through the injection hole. The needle is linearly driven within the nozzle body and includes a seat portion and a conical portion. The seat portion engages the valve seat to stop the supply of pressurized fuel to the pocket chamber. The conical portion has a conical shape with the seat portion as a boundary portion thereof and is inserted into the pocket chamber. Suppose that: the direction of movement of the needle is axial; the moving direction of the needle is the upper side when the fuel injection is started; the central point of the ball with the spherical surface of the bag-shaped chamber is the bag central point; a straight line which axially passes through the center point of the bag is the bag center line; a straight line obtained by extending the center axis of the nozzle hole to the bag-like chamber is a nozzle hole extension line, the nozzle hole extension line intersects with the bag center line, and an actual intersection point where the nozzle hole extension line and the bag center line intersect with each other is located on the upper side of the bag center point.

To achieve the first object of the present disclosure, there is also provided a fuel injection nozzle including a nozzle body and a needle. The nozzle body includes a valve seat, a pocket chamber, and a nozzle hole. The valve seat is formed inside the nozzle body and has a conical surface shape. The sac-like chamber is formed inside the nozzle body, and has a spherical shape that fuses together the pressurized fuel passing through the inside of the valve seat. The pressurized fuel supplied into the sac chamber is injected outside the nozzle body through the injection hole. The needle is linearly driven within the nozzle body and includes a seat portion and a conical portion. The seat portion engages the valve seat to stop the supply of pressurized fuel to the pocket chamber. The conical portion has a conical shape with the seat portion as a boundary portion thereof and is inserted into the pocket chamber. Suppose that: the direction of movement of the needle is axial; the direction perpendicular to the axial direction is a vertical direction; the moving direction of the needle is the upper side when the fuel injection is started; the central point of the ball with the spherical surface of the bag-shaped chamber is the bag central point; a straight line which axially passes through the center point of the bag is the bag center line; a straight line obtained by extending the center axis of the nozzle hole into the bag-like chamber is a nozzle hole extension line; a line obtained by projecting the orifice extension line in the vertical direction is a projection line, the orifice extension line is disposed to be deviated from the bag center line, and an imaginary intersection point where the projection line and the bag center line intersect with each other is located on the upper side of the bag center point.

To achieve the second object of the present disclosure, there is further provided a fuel injection nozzle including a nozzle body and a needle. The nozzle body includes a valve seat, a pocket chamber, and a nozzle hole. The valve seat is formed inside the nozzle body and has a conical surface shape. The sac-like chamber is formed inside the nozzle body, and has a spherical shape that fuses together the pressurized fuel passing through the inside of the valve seat. The pressurized fuel supplied into the sac chamber is injected outside the nozzle body through the injection hole. The needle is linearly driven inside the nozzle body and includes a seat portion and a conical portion. The seat portion engages the valve seat to stop the supply of pressurized fuel to the pocket chamber. The conical portion is conical with the seat portion as a boundary portion thereof and is inserted into the pocket chamber. Suppose that: the direction of movement of the needle is axial; the moving direction of the needle is the lower side when the fuel injection is stopped; the central point of the ball with the spherical surface of the bag-shaped chamber is the bag central point; a straight line which axially passes through the center point of the bag is the bag center line; a straight line obtained by extending the center axis of the nozzle hole to the bag-like chamber is a nozzle hole extension line; the nozzle hole extension line intersects the bag center line, an actual intersection point at which the nozzle hole extension line and the bag center line intersect with each other is located on a lower side of the bag center point, and an angle formed from a portion of the bag center line on the lower side to the nozzle hole extension line is set in a range of 60 to 85 degrees.

To achieve the second object of the present disclosure, there is still further provided a fuel injection nozzle including a nozzle body and a needle. The nozzle body includes a valve seat, a pocket chamber, and a nozzle hole. The valve seat is formed inside the nozzle body and has a conical surface shape. The sac-like chamber is formed inside the nozzle body, and has a spherical shape that fuses together the pressurized fuel passing through the inside of the valve seat. The pressurized fuel supplied into the sac chamber is injected outside the nozzle body through the injection hole. The needle is linearly driven inside the nozzle body and includes a seat portion and a conical portion. The seat portion engages the valve seat to stop the supply of pressurized fuel to the pocket chamber. The conical portion has a conical shape with the seat portion as a boundary portion thereof and is inserted into the pocket chamber. Suppose that: the direction of movement of the needle is axial; the direction perpendicular to the axial direction is a vertical direction; the moving direction of the needle is the upper side when the fuel injection is started; the central point of the ball with the spherical surface of the bag-shaped chamber is the bag central point; a straight line which axially passes through the center point of the bag is the bag center line; a straight line obtained by extending the center axis of the nozzle hole into the bag-like chamber is a nozzle hole extension line; a line obtained by projecting the orifice extension line in the vertical direction is a projection line, the orifice extension line is provided so as to be deviated from the bag center line, the side opposite to the upper side in the axial direction is a lower side, an imaginary intersection point at which the projection line and the bag center line intersect with each other is located below the bag center point, and an angle formed from a part of the bag center line on the lower side to the projection line is set within a range of 60 to 85 degrees.

Drawings

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. In the drawings:

fig. 1A is a sectional view showing main components of a fuel injection nozzle as viewed from a vertical direction according to a first embodiment;

FIG. 1B is a view showing that an orifice extending line intersects a bag center line according to the first embodiment;

FIG. 2A is a diagram showing a nozzle at low lift time according to a first embodiment;

FIG. 2B is a diagram showing the nozzle at a high lift time according to the first embodiment;

FIG. 3 is a graph showing the relationship between the lift amount and the spray penetration force of the first embodiment;

FIG. 4A is a sectional view showing the main components of the fuel injection nozzle as viewed from the vertical direction according to the second embodiment;

FIG. 4B is a diagram showing an orifice extension line offset from the bag centerline according to a second embodiment;

FIG. 5A is a sectional view showing the main components of a fuel injection nozzle seen from the vertical direction according to a third embodiment;

FIG. 5B is a view showing that an orifice extending line intersects the bag center line according to the third embodiment;

FIG. 6A is a diagram showing a nozzle at low lift time according to a third embodiment;

FIG. 6B is a diagram showing a nozzle at a high lift time according to a third embodiment;

FIG. 7 is a graph showing the relationship between the lift amount and the spray penetration force of the third embodiment;

FIG. 8A is a sectional view showing the main components of a fuel injection nozzle seen from the vertical direction according to a fourth embodiment;

fig. 8B is a diagram showing an orifice extension line deviated from the bag center line according to the fourth embodiment.

Detailed Description

Embodiments will be described below with reference to the accompanying drawings. The embodiment disclosed in the following description illustrates an example, and the present disclosure is obviously not limited to this embodiment.

(first embodiment)

A first embodiment is described with reference to fig. 1A to 3. An engine disposed in a vehicle includes a fuel injection system.

The fuel injection system exemplified in the present embodiment is for a diesel engine, which includes a common rail that accumulates high-pressure fuel pressure. The injector that injects the high-pressure fuel in the fuel injection system is a direct injection type injector that is arranged for each cylinder of the engine to directly inject the fuel to each cylinder.

The injector includes a fuel injection nozzle having a nozzle body 1 supplied with pressurized fuel from a common rail and a needle 2 driven in a linear direction in the nozzle body 1.

The mode of driving the needle 2 is not particularly specified, and various driving modes may be applied, such as a solenoid valve type injector that drives the needle 2 by controlling the oil pressure by a solenoid valve, a piezo type injector that drives the needle 2 by controlling the oil pressure by a piezo actuator, or an electromagnetic driving type injector that directly drives the needle 2 by an electromagnetic actuator.

The fuel injection nozzle will be specifically explained below. A nozzle hole 4 for guiding the fuel from the upper side to the lower side is formed in the nozzle body 1. A space S to which high-pressure fuel is supplied from the common rail is formed between the injection hole 4 and the needle 2.

Inside the nozzle body 1, a valve seat 5 having a conical surface shape and a sac-like chamber 6 having a spherical surface shape are formed, wherein pressurized fuel passing through the inside of the valve seat 5 is merged together in the sac-like chamber 6. A valve seat 5 is formed at the lower end of the nozzle hole 4. The conical surface of the valve seat 5 is formed such that its diameter gradually decreases from the upper side to the lower side.

The bag-like chamber 6 is formed by combining a cylindrical surface 6a formed on the lower side of the valve seat 5 and a hemispherical surface 6b formed on the lower side of the cylindrical surface 6 a. Specifically, a hemispherical bulged portion 7 exposed to the combustion chamber of the engine is provided on the outer surface of the lower end of the nozzle body 1. A pocket-like chamber 6 is formed inside the raised portion 7.

The nozzle body 1 comprises one or more injection holes 3, through which pressurized fuel supplied to the pocket chamber 6 is injected outside the nozzle body 1. An example of forming more than one injection hole 3 is explained below as a specific example. The nozzle hole 3 is provided through the inside and outside of the raised portion 7. Specifically, the nozzle hole 3 is a shaft hole formed to pass through the bulging portion 7 obliquely from the inner wall surface of the bag-like chamber 6 to the outer wall surface of the bulging portion 7, and is formed by, for example, cutting work by a drill or the like or electric discharge machining. As one example of the injection hole 3, fig. 1A and 1B show that the injection hole 3 is shaped as a circular hole having a constant diameter, but the shape of the injection hole 3 is not limited to the circular hole.

The fuel injection nozzle exemplified in the present embodiment uses a wide-angle injection type nozzle. In the following description, for convenience of explanation, the center point of the sphere having a spherical surface in the pocket chamber 6, i.e., the center point of the diameter of the hemispherical surface 6b, is referred to as a pocket center point P1. A straight line extending axially through the bag center point P1 is referred to as the bag center line L1. A straight line obtained by extending the center axis of the nozzle hole 3 to the bag-like chamber 6 is referred to as a nozzle hole extension line L2. The angle formed from the lower side of the bag center line L1 to the orifice extension line L2 is referred to as the spray angle θ 1.

The wide-angle injection type nozzle is a fuel injection nozzle having an injection angle θ 1 in the range of 60 to 85 degrees. As shown in fig. 1A and 1B, two injection holes 3 opposite to each other about the bag center line L are explained in detail as a specific embodiment. In this case, an angle formed from the orifice extension line L2 of one orifice 3 to the orifice extension line L2 of the other orifice 3 through the bag center line L1 located on the lower side is in the range of 120 to 170 degrees.

According to the fuel injection nozzle of the present embodiment, as shown in fig. 1B, the injection hole extension line L2 forms an actual intersection with the bag center line L1. As shown in fig. 1A, the intersection point where the orifice extension line L2 and the bag center line L1 actually intersect each other is referred to as an actual intersection point JP 2. Fig. 1B shows a cross section of the nozzle along the nozzle hole 3, but not perpendicular to the axial direction. FIG. 1B shows a cross-section of the nozzle as viewed axially with a centerline L1 in the bag as indicated by the dots in FIG. 1B.

The injection characteristics required for the fuel injection nozzle of the present embodiment should be: for example, injection characteristics with low penetration and high diffusibility are required at the light load time when the injection quantity is small to avoid the cooling loss of the fuel injected through the injection hole 3 by wall surface cooling of the combustion chamber, and conversely, injection characteristics with high penetration are required at the high load time when the injection quantity is large to contribute to the improvement of the exhaust gas.

To meet this requirement, in the fuel injection nozzle of the present embodiment, as shown in fig. 2A and 2B, the actual intersection point JP2 as described above is provided on the upper side of the bag center point P1. The axial length from the bag center point P1 to the actual intersection point JP2 is not limited and can be set according to the desired spray penetration. Specifically, if it is recommended to form a smaller spray penetration force at a light load time when the ejection volume is small, the length from the bag center point P1 to the actual intersection point JP2 is set long so that the entrance of the ejection hole 3 is away from the bottom of the bag-like chamber 6.

The needle 2 has a shaft shape extending in the up-down direction, and is supported to be able to be driven in the up-down direction in the central portion of the nozzle hole 4. An annular seat 8, which engages with the valve seat 5 to stop the supply of pressurized fuel into the pocket 6, is provided on the needle 2.

The seat 8 is formed at the interface between two conical surfaces having different expansion angles. Specifically, the divergent angle of the conical surface on the upper side of the seat portion 8 is smaller than the divergent angle of the valve seat 5. The divergent angle of the conical surface on the lower side of the seat portion 8 is larger than that of the valve seat 5. The conical area located below the seat 8 is referred to as the conical portion 9, as will be explained below. Thus, the needle 2 comprises a conical portion 9 of conical shape, the diameter of which decreases from the seat 8 towards the lower side, the seat 8 being the boundary portion thereof.

The fuel injection nozzle of the present embodiment is of a conical insertion type, whereby a part of the conical portion 9 is inserted into the pocket chamber 6, and the conical portion 9 overlaps with the pocket chamber 6 in the axial direction. Specifically, this type of nozzle has the undercut 10 formed at the lower end of the conical portion 9 located on the lower side of the boundary line 11 between the valve seat 5 and the bag-like chamber 6. The shape of the undercut portion 10 is not limited, and may be a flat surface perpendicular to the axial direction as shown in fig. 2A and 2B, or may be a conical surface having a spread angle larger than that of the conical portion 9, unlike fig. 2A and 2B.

The following is a supplementary description of the conical insertion type. In the fuel injection nozzle of the conical insertion type, when the seat portion 8 is engaged with the valve seat 5, the undercut portion 10 is located on the lower side of the boundary line 11, and the conical portion 9 and the sac chamber 6 axially overlap each other. At the maximum lifting time of the needle 2, the conical portion 9 may axially overlap the pocket 6. Alternatively, the conical portion 9 may be disengaged from the pocket 6 at the maximum lifting time.

In a state where the needle 2 moves upward and the seat 8 is disengaged from the valve seat 5, the supply side of the pressurized fuel and the injection holes 3 communicate with each other, whereby the fuel is injected through the injection holes 3. In contrast, in a state where the needle 2 moves downward and the seat 8 engages with the valve seat 5, the communication between the supply side of the pressurized fuel and the injection hole 3 is closed, thereby stopping the fuel injection.

The change in the spray penetration force with respect to the change in the lift amount of the needle 2 will be described in detail below. At the time of light load, in the fuel injection nozzle of the first embodiment, the actual intersection point JP2 of the orifice extension line L2 and the bag center line L1 is disposed above the bag center point P1 as described above. Thus, the inlet of the nozzle hole 3 opens at the upper side of the pocket chamber 6 compared to the prior art. In this manner, at a low lift time when the injection quantity is small, as shown by arrow α 1 in fig. 2A, when the pressurized fuel supplied to the pocket chamber 6 temporarily collides against the bottom of the pocket chamber 6 and flows into the injection hole 3 from the bottom side of the pocket chamber 6, the distance traveled by the fuel is longer than in the related art. Therefore, the ejection energy in the pocket chamber 6 is greatly reduced. Therefore, as shown along a solid line B1 in fig. 3, the fuel injected through the injection hole 3 has a small spray penetration force at a low lift time.

In the fuel injection nozzle, at a high load time, at a high lift time when the injection quantity is large, the sac chamber 6 is filled with the pressurized fuel to have a high pressure. In this case, as shown by an arrow β 1 in fig. 2B, after the pressurized fuel collides with the bottom of the sac chamber 6, the pressurized fuel does not return, and the high-pressure fuel supplied to the sac chamber 6 flows directly into the injection holes 3, and the fuel draws an arc and straightens. Therefore, as shown along a solid line B1 in fig. 3, the fuel injected from the injection hole 3 has a large spray penetration force at a high lift time.

The alternate long and short dash line a in fig. 3 represents the prior art characteristic of the actual intersection point JP2 being located at the bag center point P1. The solid line B1 in fig. 3 indicates the degree of change in the spray penetration force relative to the alternate long and short dash line a.

The effects of the first embodiment will be described below. By adopting the first embodiment described above, it is possible to provide a conical insertion type fuel injection nozzle having a small spray penetration force at a low lift time when the injection quantity is small, and conversely, having a large spray penetration force at a high lift time when the injection quantity is large. Therefore, for example, at a light load time when the injection quantity is small, the injection characteristic of low penetration and diffusion injection can be provided to avoid a cooling loss of the fuel injected by wall surface cooling of the combustion chamber, and at a high load time when the injection quantity is large, the injection characteristic of high penetration can be provided to contribute to improvement of the exhaust gas.

(second embodiment)

A second embodiment will be described with reference to fig. 4A and 4B. In the following embodiments, the same numerals as in the first embodiment denote the same functional components. The following embodiments disclose only the modified portions with respect to the first embodiment, and the foregoing embodiments are employed for undescribed components.

As shown in fig. 4B, the fuel injection nozzle of the second embodiment is of the type: its orifice extension line L2 does not directly intersect the bag centerline L1. More specifically, the orifice extension line L2 is disposed offset from the bag centerline L1.

In the following description, a line obtained by projection of the orifice extension line L2 in the vertical direction is referred to as a projection line KL 2. In this second embodiment, as shown in FIG. 4A, an imaginary intersection point KP2, where projection line KL2 intersects bag centerline L1, is located at the upper side of bag center point P1. The other structures are similar to those in the first embodiment, and explanation thereof will be omitted.

By disposing the imaginary intersecting point KP2 on the upper side of the bag center point P1 in this way, operation and effects similar to those of the first embodiment can be obtained.

(third embodiment)

A third embodiment will be described below with reference to fig. 5A to 7. As shown in fig. 5B, the fuel injection nozzle of the third embodiment is provided such that the orifice extension line L2 actually intersects the bag center line L1. In the fuel injection nozzle of this third embodiment, as shown in fig. 5A, the actual intersection point JP2 is disposed on the lower side of the bag center point P1. The other structures are similar to those in the first embodiment, and explanation thereof will be omitted.

The change in the spray penetration force with respect to the change in the lift amount of the needle 2 will be described below. In the fuel injection nozzle of the third embodiment, at the time of light load, the actual intersection point JP2 is disposed on the lower side of the bag center point P1 as described above. Thus, compared to the prior art, the inlet of the nozzle hole 3 opens at the lower part of the pocket chamber 6. In this way, at a low lift time when the injection quantity is small, as shown by arrow α 2 in fig. 6A, the phenomenon that the pressurized fuel returns after the pressurized fuel collides against the bottom of the sac chamber 6 is suppressed, and the pressurized fuel supplied to the sac chamber 6 directly flows into the injection holes 3. Therefore, at a low lift time as shown along a solid line B2 in fig. 7, the fuel injected through the injection hole 3 has a large spray penetration force.

In the fuel injection nozzle of the third embodiment, the injection angle θ 1 is set to a wide angle of 60 to 85 degrees at the time of high load, similarly to the first embodiment. For this reason, as shown in fig. 6B, an angle θ 2 formed from the orifice extension line L2 to the upper portion of the tangent of the spherical surface configured as the bag-like chamber 6 is set to be an acute angle. Therefore, the pressurized fuel supplied to the sac chamber 6 does not easily flow into the nozzle hole 3. Therefore, the flow direction of the fuel is sharply bent in the pocket chamber 6, and the injection energy in the pocket chamber 6 can be reduced. Therefore, at a high lift time, when the sac chamber 6 is filled with the pressurized fuel with a high pressure, the fuel injected through the injection hole 3 has a small spray penetration force as shown in fig. 7 along the high lift time shown by the achievement B2.

The alternate long and short dash line a in fig. 7 represents the prior art, i.e., the characteristic of the actual intersection point JP2 being located at the bag center point P1, and the solid line B2 in fig. 7 represents the degree of change in the spray penetration force relative to the alternate long and short dash line a.

The effects of the third embodiment will be described below. By adopting the above-described third embodiment, it is possible to provide a conical insertion type fuel injection nozzle having a large spray penetration force at a low lift time when the injection quantity is small and a small spray penetration force at a high lift time when the injection quantity is large.

(fourth embodiment)

A fourth embodiment will be described below with reference to fig. 8A and 8B. As shown in fig. 8B, the fuel injection nozzle of the fourth embodiment is of the type: such that the orifice extension line L2 does not directly intersect the bag centerline L1. More specifically, similar to the second embodiment described above, the orifice extension line L2 is disposed offset from the bag centerline L1.

In this fourth embodiment, as shown in FIG. 8A, an imaginary intersection point KP2, where projection line KL2 intersects bag centerline L1, is located at the lower side of center point P1 of the bag. The other structures are similar to those in the first embodiment, and explanation thereof will be omitted.

By disposing the imaginary intersecting point KP2 on the lower side of the bag center point P1 in this manner, operation and effects similar to those of the third embodiment can be obtained.

The present disclosure is not limited to the above-described embodiments, and the following modes may also be adopted. Changes to the above-described embodiment will be explained below.

The above-described first embodiment shows the wide-angle injection type, i.e., the injection angle θ 1 is in the range of 60 to 85 degrees. However, when the actual intersection point JP2 is disposed on the upper side of the bag center point P1, the injection angle θ 1 is not limited thereto. That is, when the actual intersection point JP2 is disposed on the upper side of the bag center point P1, the ejection angle θ 1 may be set smaller than 60 degrees, or the ejection angle θ 1 may be set larger than 85 degrees. Similarly, when the imaginary intersecting point KP2 is disposed on the upper side of the bag center point P1, the spray angle θ 1 is not limited to the range of 60-85 degrees. The injection angle θ 1 may be set to be smaller than 60 degrees, or the injection angle θ 1 may be set to be larger than 85 degrees.

In the first to fourth embodiments described above, application of the present disclosure to a fuel injection nozzle for a diesel engine is exemplified. The diesel engine is a compression ignition type internal combustion engine. Therefore, the fuel injected through the fuel injection nozzle is not limited to light oil, and other fuels suitable for compression ignition, such as dimethyl ether, may be used.

The first to fourth embodiments described above show the application of the present disclosure to a fuel injection nozzle for use in a diesel engine. Of course, the present disclosure is also applicable to fuel injection nozzles for use in gasoline engines.

The fuel injection nozzle may be a full-circle injection type that injects fuel around the fuel injection nozzle, a two-side injection type that injects fuel to both sides of the fuel injection nozzle, or a single-side injection type that injects fuel to only one side of the fuel injection nozzle.

In summary, the fuel injection nozzle according to the above-described embodiment can be described as follows.

In the first aspect of the present disclosure, the actual intersection of the orifice extension line L2 and the bag centerline L1 is disposed on the upper side of the bag center point P1. In a second aspect of the present disclosure, an imaginary intersection KP2 of projected line KL2 and bag centerline L1 is disposed above bag center point P1. Therefore, in the first and second aspects, the inlet of the orifice 3 is opened at the upper portion of the pocket chamber 6, compared to the prior art. Thus, at the low lift time, when the pressurized fuel supplied to the pocket chamber 6 temporarily collides against the bottom of the pocket chamber 6 and flows into the injection hole 3 from the bottom of the pocket chamber 6, the distance that the fuel travels becomes long. Therefore, the ejection energy is greatly reduced in the pocket chamber 6. Thus, the fuel injected through the injection hole 3 has a smaller spray penetration force than in the related art. In contrast, at a high lift time, the sac chamber 6 is filled with pressurized fuel to have a higher pressure. Therefore, the pressurized fuel does not return after the fuel collides against the bottom of the sac chamber 6, and the high-pressure fuel supplied to the sac chamber 6 directly flows into the injection holes 3. Thus, the fuel injected through the injection hole 3 has a larger spray penetration force than the low lift time. Therefore, the first and second aspects can provide a conical insertion-type fuel injection nozzle having a small spray penetration force at a low lift time and a large spray penetration force at a high lift time.

In the fourth aspect of the present disclosure, the actual intersection of the orifice extension line L2 and the pouch centerline L1 is disposed on the lower side of the pouch center point P1. In a fifth aspect of the present disclosure, an imaginary intersection KP2 of projected line KL2 and bag centerline L1 is disposed below bag center point P1. Therefore, in the fourth and fifth aspects, the inlet of the nozzle hole 3 is opened at the lower portion of the pocket chamber 6, compared to the prior art. Thus, at the low lift time, the phenomenon that the pressurized fuel supplied to the pocket chamber 6 returns after temporarily colliding against the bottom of the pocket chamber 6 is suppressed, and the pressurized fuel supplied to the pocket chamber 6 directly flows into the injection holes 3. Therefore, the fuel injected through the injection hole 3 has a greater spray penetration force compared to the related art. In the fourth and fifth aspects, the injection angle θ 1 is set in the wide-angle range of 60 to 85 degrees. Therefore, an angle θ 2 formed from the injection hole extension line L2 to an upper portion of a spherical tangent line configured as the pocket chamber 6 is set to be an acute angle. Thus, the pressurized fuel supplied to the sac chamber 6 cannot easily flow into the nozzle hole 3. Therefore, the flow direction of the fuel in the pocket chamber 6 is rapidly bent, and the injection energy in the pocket chamber 6 is reduced. Therefore, at a high lift time, when the sac chamber 6 is filled with the pressurized fuel to have a high pressure, the fuel injected through the injection hole 3 has a smaller spray penetration force than that of the related art. In this way, the fourth and fifth aspects can provide a conical insertion-type fuel injection nozzle having a large spray penetration force at a low lift time and a small spray penetration force at a high lift time.

While the disclosure has been described in connection with embodiments, it is to be understood that the disclosure is not limited to the described embodiments and constructions. The disclosure is intended to cover various modifications and equivalent arrangements. In addition, while various combinations and configurations, including more, less or only a single element, are possible, other combinations and configurations are also within the spirit and scope of the disclosure.

Claims

1. A fuel injection nozzle comprising:

a nozzle body (1) comprising:

a valve seat (5) formed in the nozzle body (1) and having a conical surface shape;

a pocket chamber (6) formed in the nozzle body (1) and having a spherical shape that fuses together the pressurized fuel passing through the inside of the valve seat (5); and

a nozzle hole (3) through which the pressurized fuel supplied into the sac-like chamber (6) is injected outside the nozzle body (1); and

a needle (2) driven linearly inside a nozzle body (1), comprising:

a seat (8) that engages with the valve seat (5) to stop the supply of pressurized fuel into the pocket chamber (6); and

a conical part (9) having a conical shape with the seat part (8) as a boundary part thereof and inserted into the bag-like chamber (6), wherein

It is known that:

the displacement direction of the needle-shaped piece (2) is axial;

the direction in which the needle (2) is displaced when fuel injection starts is the upper side;

the central point of the spherical ball with the bag-shaped chamber (6) is the bag-shaped central point (P1);

a straight line extending axially through the bag center point (P1) is the bag centerline (L1); and

a straight line obtained by extending the center axis of the nozzle hole (3) into the bag-like chamber (6) is a nozzle hole extension line (L2),

an orifice extension line (L2) disposed to intersect the pouch centerline (L1); and is

An actual intersection point (JP2) where the orifice extension line (L2) and the bag center line (L1) intersect with each other is provided on the upper side of the bag center point (P1),

the conical part (9) has a flat surface at its lower end, and

said flat surface being located on the lower side of the bag center point (P1) in the range of movement of the needle (2) between a position in which the valve seat (5) engages with the seat (8) and a high lift,

the bag-shaped chamber (6) has the spherical surface on the side of the orifice (3) with respect to the bag center point (P1),

the distance between the center point (P1) of the pocket and the sphere is constant,

said seat (8) being formed at the interface between a first conical surface and a second conical surface having different expansion angles,

said first conical surface being located on the upper side of said seat (8) and being smaller than the spread angle of said valve seat (5),

the second conical surface is located on the lower side of the seat (8) and is greater than the spread angle of the valve seat (5), and

the second conical surface is continuous with the flat surface of the conical portion (9).

2. The fuel injection nozzle according to claim 1, wherein:

the side opposite to the upper side in the axial direction is a lower side; and

an angle (theta 1) from a part of the bag center line (L1) on the lower side to the orifice extension line (L2) is set within the range of 60-85 degrees.

3. A fuel injection nozzle comprising:

a nozzle body (1) comprising:

a needle (2) driven linearly inside a nozzle body (1), comprising:

It is known that:

the displacement direction of the needle-shaped piece (2) is axial;

the direction perpendicular to the axial direction is a vertical direction;

a straight line extending axially through the bag center point (P1) is the bag centerline (L1);

a straight line obtained by extending the center axis of the nozzle hole (3) into the bag-like chamber (6) is a nozzle hole extension line (L2); and

the line obtained by projecting the nozzle hole extension line (L2) in the vertical direction is a projection line (KL2),

the orifice extension line (L2) is disposed offset from the bag centerline (L1); and

an imaginary intersection point (KP2) at which the projected line (KL2) and the bag centerline (L1) intersect each other is disposed on the upper side of the bag center point (P1),

the conical part (9) has a flat surface at its lower end, and

4. A fuel injection nozzle comprising:

a nozzle body (1) comprising:

a needle (2) driven linearly inside a nozzle body (1), comprising:

It is known that:

the displacement direction of the needle-shaped piece (2) is axial;

the direction in which the needle (2) is displaced when fuel injection is stopped is the lower side;

a straight line obtained by extending the center axis of the nozzle hole (3) into the bag-like chamber (6) is a nozzle hole extension line (L2);

an orifice extension line (L2) disposed to intersect the pouch centerline (L1);

an actual intersection point (JP2) where the orifice extension line (L2) and the bag center line (L1) intersect with each other is provided on the lower side of the bag center line (L1); and is

An angle (theta 1) from a part of the bag center line (L1) on the lower side to the orifice extension line (L2) is set within the range of 60-85 degrees,

the conical part (9) has a flat surface at its lower end, and

5. A fuel injection nozzle comprising:

a nozzle body (1) comprising:

a needle (2) driven linearly inside a nozzle body (1), comprising:

It is known that:

the displacement direction of the needle-shaped piece (2) is axial;

the direction perpendicular to the axial direction is a vertical direction;

a straight line obtained by extending the center axis of the nozzle hole (3) into the bag-like chamber (6) is a nozzle hole extension line (L2); and is

the orifice extension line (L2) is disposed offset from the bag centerline (L1);

the side opposite to the upper side in the axial direction is a lower side;

an imaginary intersection point (KP2) at which the projected line (KL2) and the bag centerline (L1) intersect each other is disposed at a lower side of the bag center point (P1); and

an angle (theta 1) from a part of the bag center line (L1) at the lower side to a projection line (KL2) is set within the range of 60 to 85 degrees,

the conical part (9) has a flat surface at its lower end, and