JP2014199021A - Fuel injection device and diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection device and a diesel engine capable of reducing the amount of fuel oil supplied to a combustion chamber during closing of a valve.SOLUTION: A fuel injection device 10 comprises: a housing 14; a needle valve 26; a spool valve 44 provided on a tip end of the needle valve 26; and a vertical groove 23 formed at a different position from those of fuel injection holes 16a to 16d, and communicating with a fuel supply path 24. A fuel oil introduction space 27 in which fuel oil circulates is formed in the spool valve 44. When the fuel supply path 24 is open, the fuel oil introduction space 27 is moved to a position at which the fuel oil introduction space 27 communicates with the vertical groove 23 and the fuel oil introduction space 27 communicates with the fuel injection holes 16a to 16d. When the fuel supply path 24 is closed, the fuel oil introduction space 27 is moved to a position at which an outer circumferential surface of the spool valve 44 faces the fuel injection holes 16a to 16d and the fuel oil introduction space 27 does not communicate with the fuel injection holes 16a to 16d.

Description

  The present invention relates to a fuel injection device used in an internal combustion engine such as a diesel engine and a diesel engine.

The fuel injection device is provided in a cylinder head of an internal combustion engine such as a diesel engine, and a front end portion of the housing of the fuel injection device protrudes into the combustion chamber. A fuel injection hole is formed at the tip of the housing, and a needle valve is installed inside the housing. The needle valve is opened away from the valve seat by the hydraulic pressure of the fuel oil supplied into the housing, and the fuel oil is supplied to the fuel injection hole. As a result, fuel oil is injected from the fuel injection hole into the combustion chamber. In the combustion chamber, the fuel oil is mixed with air and ignited to form a flame, and the flame spreads throughout the combustion chamber.
Patent Document 1 describes that a cutoff member having two cylindrical portions that fit into a central hole in a sprayer is provided at the tip of a valve shaft. Two cylindrical members consist of the 1st cylindrical part located in the lower side, and the 2nd cylindrical part located in the upper side.

Special table 2010-512484 gazette

  The fuel injector described in Patent Document 1 is formed on the outer peripheral surface of the second cylindrical portion of the cutoff member and the axial center of the sprayer with respect to the second group of nozzle holes located on the upper side. Fuel oil is supplied through a passage between the inner peripheral surface of the center hole. On the other hand, when the valve stem is in the closed position, the periphery of the second cylindrical portion is fitted into the center hole, so that the fuel supply to the nozzle holes of the second group is blocked.

  By the way, in the fuel injector described in Patent Literature 1, an annular recess is formed between the first cylindrical portion and the second cylindrical portion. However, when the valve stem is in the closed position, the annular recess communicates with the second group of nozzle holes. For this reason, even when the valve is closed, the fuel oil accumulated in the annular recess travels through the second nozzle hole, and a trailing sag occurs in which the fuel oil is supplied to the combustion chamber. That is, the formation of the annular recess increases the sack volume of the fuel injector.

  Further, in the fuel injector described in Patent Document 1, when the valve stem is in the open position, the second cylindrical portion is disengaged from the center hole, and only the first cylindrical portion is in the center hole. Is fitted. For this reason, the slide of the shaft of the valve stem tends to become unstable. When the valve stem moves to the closed position, the second cylindrical portion comes into contact with and fits with the inner peripheral surface of the center hole, so that the shaft is easily damaged.

  The present invention has been made in view of such circumstances, and provides a fuel injection device and a diesel engine capable of reducing the amount of fuel oil supplied to a combustion chamber when a valve is closed. Objective.

In order to solve the above problems, the fuel injection device and the diesel engine of the present invention employ the following means.
That is, the fuel injection device according to the present invention includes a housing in which a fuel supply passage is formed and a fuel injection hole is formed at a tip portion, and the fuel supply passage that is disposed in the housing and is arranged in accordance with fuel hydraulic pressure. A needle valve that opens and closes, a spool valve that is provided at the tip of the needle valve, and whose outer peripheral surface slides in contact with the inner peripheral surface of the housing, and a position different from the fuel injection hole on the inner peripheral surface of the housing And a fuel oil introduction space through which fuel oil flows is formed in the spool valve, and when the fuel supply path is opened, the fuel oil introduction space is formed in the groove portion. The fuel oil introduction space moves to a position where it communicates with the fuel injection hole, and when the fuel supply passage is closed, the outer peripheral surface of the spool valve faces the fuel injection hole, It moved to a position where entrance space is not the fuel injection hole and communicating.

  According to this configuration, when the fuel supply path is opened, the fuel oil introduced from the groove portion is injected from the fuel injection hole through the fuel oil introduction space of the spool valve. On the other hand, when the fuel supply passage is closed, the outer peripheral surface of the needle valve faces the fuel injection hole, and the fuel oil introduction space does not communicate with the fuel injection hole. Will not be supplied. Therefore, when the needle valve is closed, the fuel oil accumulated in the fuel oil introduction space does not sag because the fuel oil is supplied to the combustion chamber through the fuel injection hole.

  In the above invention, it is desirable that the upper outer peripheral surface of the spool valve always contacts the inner peripheral surface of the housing during the opening / closing operation of the fuel supply passage.

  According to this configuration, when the outer peripheral surface of the spool valve slides in contact with the inner peripheral surface of the housing by the opening / closing operation of the fuel supply passage, the outer peripheral surface of the spool valve positioned above the fuel oil introduction space is It is always in contact with the inner peripheral surface of the housing. Further, when the fuel supply path is opened, the fuel oil is introduced from the groove portion into the fuel oil introduction space of the spool valve. As a result, even when a concave fuel oil introduction space is formed in the spool valve, the needle valve is supported on the housing by the outer peripheral surface of the upper part of the fuel oil introduction space, so the behavior of the needle valve is stabilized. To do. Further, since the outer peripheral surface of the spool valve is always in contact with the inner peripheral surface of the housing, damage due to repeated contact and non-contact is unlikely to occur.

  In the above invention, the fuel oil introduction space may be formed in an annular shape by the spool valve.

  According to this configuration, the fuel injection hole is provided in the housing at a position different from the groove portion, and the fuel oil introduction space is formed in an annular shape on the outer periphery of the spool valve. The flow resistance of the fuel oil until it is injected from the injection hole through the introduction space is constant regardless of the rotational position of the needle valve. That is, even when the needle valve rotates about the axis, the flow resistance of the fuel oil does not change, and the fuel oil can be stably injected.

  On the other hand, without forming a groove in the housing, for example, by forming a groove along the axial direction in the shaft of the needle valve or by forming a through hole in the axial direction in the spool valve, A reference example of supplying fuel can be considered. However, in the case of this reference example, the position where the fuel oil is introduced into the fuel oil introduction space approaches or moves away from the fuel injection hole according to the rotational position of the needle valve, so that the fuel oil is injected from the fuel injection hole. The flow path resistance until it changes. On the other hand, in the present invention, since the position where the fuel oil is introduced into the fuel oil introduction space (the position of the groove formed in the housing) and the position of the fuel injection hole are constant, the flow resistance of the fuel oil does not change.

  In the above invention, the fuel injection hole is provided with an upper fuel injection hole and a lower fuel injection hole in the axial direction in the housing, and a fuel supply for supplying fuel to the space below the spool valve inside the spool valve When the fuel supply passage is opened, the fuel oil introduction space communicates with the groove, and the fuel oil introduction space moves to a position where it communicates with the upper fuel injection hole. The lower space may communicate with the groove, and the space below the spool valve may communicate with the lower fuel injection hole.

  According to this configuration, when the fuel supply path is opened, the fuel oil introduced from the groove portion is injected from the upper fuel injection hole through the fuel oil introduction space, and at the same time, the lower fuel is supplied through the space below the spool valve. Inject from the injection hole. Since the fuel oil introduction space and the space below the spool valve communicate with each other via a groove formed in the inner peripheral surface of the housing, the fuel oil injected from the upper fuel injection hole and the lower fuel injection hole The flow path resistance and the injection pressure can be maintained uniformly.

  In the above invention, a plurality of the groove portions may be formed on the inner peripheral surface of the housing, and the plurality of groove portions may be provided on the inner peripheral surface of the housing at equal intervals.

  According to this configuration, when the needle valve receives a reaction force due to the fuel oil introduced into the groove portion, the groove portion is evenly provided, so that the position of the needle valve is less likely to be biased. Therefore, the possibility that the spool valve is pressed against the inner peripheral surface of the housing and the sliding surface is damaged can be reduced.

  In the above invention, the groove portion and the fuel injection hole may be formed at a distance equal to or larger than the diameter of the fuel injection hole.

  According to this configuration, when the needle valve is closed, the fuel oil flows out from the fuel injection hole through the gap between the inner peripheral surface of the housing and the outer peripheral surface of the spool valve between the groove and the fuel injection hole. The possibility of doing so can be reduced.

  The diesel engine which concerns on this invention equips a cylinder head with the above-mentioned fuel-injection apparatus.

  According to this configuration, the fuel injection device is provided in the cylinder head of the diesel engine, and the fuel injection device is configured such that when the fuel supply path is opened, the fuel oil introduced from the groove portion is fueled via the fuel oil introduction space of the spool valve. Inject from the injection hole. On the other hand, when the fuel supply passage is closed, the outer peripheral surface of the needle valve faces the fuel injection hole, and the fuel oil introduction space does not communicate with the fuel injection hole. Will not be supplied. Therefore, when the needle valve is closed, the fuel oil accumulated in the fuel oil introduction space does not sag because the fuel oil is supplied to the combustion chamber through the fuel injection hole.

  According to the present invention, the amount of fuel oil supplied to the combustion chamber when the valve is closed can be reduced.

It is the schematic and longitudinal cross-sectional view which show the fuel-injection apparatus which concerns on 1st Embodiment of this invention, and shows the time of valve closing of a needle valve. It is a longitudinal cross-sectional view which shows the fuel-injection apparatus which concerns on 1st Embodiment of this invention, and shows the time of valve opening of a needle valve. It is the cross-sectional view cut | disconnected by the CC line | wire of FIG. It is the cross-sectional view cut | disconnected by the DD line | wire of FIG. It is the cross-sectional view cut | disconnected by the CC line | wire of FIG. It is the cross-sectional view cut | disconnected by the DD line | wire of FIG. It is the cross-sectional view cut | disconnected by the EE line | wire of FIG. 2 or FIG. 10, and shows an example of a vertical groove. It is the cross-sectional view cut | disconnected by the EE line | wire of FIG. 2 or FIG. 10, and shows the other example of a vertical groove. It is a longitudinal cross-sectional view which shows the fuel-injection apparatus which concerns on 2nd Embodiment of this invention, and shows the time of valve closing of a needle valve. It is a longitudinal cross-sectional view which shows the fuel-injection apparatus which concerns on 2nd Embodiment of this invention, and shows the time of valve opening of a needle valve. It is the cross-sectional view cut | disconnected by CC line of FIG. It is the cross-sectional view cut | disconnected by the DD line | wire of FIG. It is the cross-sectional view cut | disconnected by CC line of FIG. It is the cross-sectional view cut | disconnected by the DD line | wire of FIG.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
A fuel injection device 10 according to a first embodiment of the present invention will be described. The fuel injection device 10 is applied to an internal combustion engine such as a two-cycle marine large diesel engine.
In the fuel injection device 10, a cylindrical housing 14 is installed on a cylinder head 12 of an internal combustion engine. FIG. 1 is a schematic view and a longitudinal sectional view showing a fuel injection device according to a first embodiment of the present invention, and shows a state in which a needle valve 26 is closed. FIG. 2 shows the needle valve 26 when it is closed.

  As shown in FIG. 1, the oil pump 38 is connected to the cylinder 34 via the oil passage 36. The cylinder 34 is connected to one end of the oil passage 32, and the other end of the oil passage 32 is connected to the fuel supply passage 18 formed in the housing 14. A piston 40 that reciprocates by a cam 42 is provided inside the cylinder 34. Fuel oil is supplied from the oil pump 38 to the cylinder 34, and the fuel oil in the cylinder 34 is supplied to the fuel supply path 18 by the rise of the piston 40.

  The housing 14 is provided with a plurality of fuel injection holes at the distal end portion 14a. The tip portion 14 a protrudes from the lower surface 12 a of the cylinder head 12 into the combustion chamber 11. A cylindrical center hole 21 is formed inside the housing 14 along the axis, and a needle valve 26 is accommodated in the center hole 21. As an example, the center hole 21 in the housing 14 is cylindrical, but is not limited thereto, and may be, for example, a rectangular tube.

  A fuel supply path 18 is formed from the upper part to the lower part of the housing 14, and the fuel supply path 18 communicates with the chamber 20. A valve seat 22 is formed on the lower surface of the chamber 20, and a fuel supply path 24 is formed inside the valve seat 22. A coil spring 30 is installed above the needle valve 26, and the elastic force of the coil spring 30 is biased toward the upper surface of the needle valve 26. As a result, when fuel oil is not supplied to the fuel supply path 18, the conical surface 28 of the needle valve 26 is pressed against the valve seat 22 to close the fuel supply path 24 provided below the chamber 20. The needle valve 26 moves upward in accordance with the hydraulic pressure of the fuel oil supplied to the fuel supply path 18, and the fuel supply path 18 and the fuel supply path 24 communicate with each other.

  A spool valve 44 is formed at the tip of the needle valve 26. A fuel supply hole 440 is provided on the axis of the spool valve 44. The fuel supply hole 440 allows the fuel supply path 24 to communicate with the space 25 formed below the spool valve 44. The spool valve 44 includes an upper large diameter portion 442 positioned on the upper side and a lower large diameter portion 444 positioned on the lower side and spaced apart from the upper large diameter portion 442. A small diameter portion 446 is formed between the upper large diameter portion 442 and the lower large diameter portion 444. The upper large diameter portion 442, the lower large diameter portion 444, and the small diameter portion 446 are, for example, cylindrical. The upper large-diameter portion 442, the lower large-diameter portion 444, and the small-diameter portion 446 may have a rectangular tube shape together with the shape of the center hole 21 inside the housing 14.

  The upper large diameter portion 442 and the lower large diameter portion 444 are fitted in the center hole 21 of the housing 14 and slide along the inner peripheral surface of the center hole 21. When the needle valve 26 closes the fuel supply passage 24, the upper large-diameter portion 442 closes the upper fuel injection holes 16a and 16b and the lower large-diameter portion as shown in FIGS. 444 closes the lower fuel injection holes 16c and 16d.

  An annular fuel oil introduction space 27 is formed at a position corresponding to the small diameter portion 446 between the upper large diameter portion 442 and the lower large diameter portion 444. The fuel oil introduction space 27 is formed in a concave shape toward the center side from the outer peripheral surface of the spool valve 44, and the fuel oil flows therethrough. When the needle valve 26 opens the fuel supply path 24 and the fuel supply path 18 and the fuel supply path 24 communicate with each other, as shown in FIGS. Facing the holes 16a and 16b, the fuel oil introduction space 27 and the fuel injection holes 16a and 16b communicate with each other. The space 25 formed below the spool valve 44 faces the lower fuel injection holes 16c and 16d as shown in FIGS. 2 and 6, and the space 25 and the fuel injection holes 16c and 16d Communicate. In addition, the fuel oil introduction space 27 should just be cyclic | annular, and is not limited to an annular | circular shape.

  The four fuel injection holes 16 a to 16 d are divided into two injection hole arrays A and B provided at different positions in the axial direction of the housing 14. The upper injection hole array A is composed of fuel injection holes 16a and 16b, and the lower injection hole array B is composed of fuel injection holes 16c and 16d. Each fuel injection hole 16a-16d is formed toward the radial direction with respect to the axis line of the housing 14, for example, as shown in FIGS. The number of fuel injection holes is not limited to four. For example, three fuel injection holes may be formed in the upper injection hole row A, and three fuel injection holes may be formed in the lower injection hole row B. The number of fuel injection holes formed in the row A and the lower injection hole row B may not match.

  A longitudinal groove 23 is formed in the inner peripheral surface of the center hole 21 of the housing 14 along the axial direction. In the housing 14, the vertical groove 23 is provided at a position different from the fuel injection holes 16a and 16b, as shown in FIGS. Regardless of the vertical position of the needle valve 26, the vertical groove 23 is formed with such a length that it always communicates with the fuel supply path 24 and the annular fuel oil introduction space 27. As a result, the fuel oil is filled in the fuel oil introduction space 27 even when the needle valve 26 closes the fuel supply path 24.

  As shown in FIGS. 7 and 8, a plurality of vertical grooves 23 may be formed on the inner peripheral surface of the housing 14. The plurality of vertical grooves 23 are provided on the inner peripheral surface of the housing at equal intervals. For example, as shown in FIG. 7, when an even number of vertical grooves 23 such as two are provided, the two vertical grooves 23 are formed to face each other at opposite positions. Further, as shown in FIG. 8, when odd-numbered vertical grooves 23 such as three are provided, the vertical grooves 23 are provided at equal intervals. The needle valve 26 receives a reaction force by the fuel oil that is pressurized and introduced into the longitudinal groove 23. At this time, since the longitudinal grooves 23 are evenly provided, the position of the needle valve 26 is less likely to be biased. Therefore, the possibility that the spool valve 44 is pressed against the inner peripheral surface of the housing 14 and the sliding surface is damaged or fixed (sticked) can be reduced.

  The distance L between the vertical groove 23 and each of the fuel injection holes 16a and 16b is preferably formed at a distance equal to or larger than the diameter d of the injection hole as shown in FIGS. Thereby, especially when the needle valve 26 is closed, the fuel oil passes through the gap between the inner peripheral surface of the housing 14 and the outer peripheral surface of the spool valve 44 between the vertical groove 23 and the fuel injection holes 16a and 16b. The possibility of flowing out from the fuel injection holes 16a and 16b can be reduced.

Next, the operation of the fuel injection device 10 according to this embodiment will be described.
When fuel oil is not supplied from the oil passage 32 to the fuel supply passage 18, the needle valve 26 is seated on the valve seat 22 and the fuel supply passage 24 is closed.
When fuel oil is supplied from the oil passage 32 to the fuel supply passage 18, the needle valve 26 rises against the elastic force of the coil spring 30 according to the oil pressure of the fuel oil, and the fuel supply passage 24 is opened. . That is, the needle valve 26 does not rise and the fuel supply path 24 is closed until the oil pressure of the fuel oil becomes equal to or higher than a certain oil pressure.
Accordingly, the fuel oil reaches the lower space 25 from the fuel supply path 18 and the fuel supply path 24 through the fuel supply hole 440. Further, the fuel oil reaches the fuel oil introduction space 27 through another path, that is, from the fuel supply path 18 and the fuel supply path 24 through the vertical groove 23.

  Along with the raising and lowering of the needle valve 26, the spool valve 44 integrated with the needle valve 26 is also raised and lowered. Depending on the position of the spool valve 44, the injection hole array A and the injection hole array B are opened and closed. When the needle valve 26 rises and the needle valve 26 opens, the fuel oil introduction space 27 communicates with the longitudinal groove 23, and the fuel oil introduction space 27 is in the fuel injection holes 16 a and 16 b of the injection hole array A. Move to a position that communicates with The lower large diameter portion 444 of the spool valve 44 opens the fuel injection holes 16c and 16d of the injection hole row B. Therefore, when the spool valve 44 is raised, all the injection holes 16a to 16d of the injection hole array A and the injection hole array B are opened.

  On the other hand, when the fuel oil is not supplied from the oil passage 32, the needle valve 26 is lowered and seated on the valve seat 22, and the fuel supply passage 24 is closed. When the needle valve 26 is seated on the valve seat 22, all the injection holes 16 a to 16 d of the injection hole row A and the injection hole row B are arranged on the outer peripheral surface of the spool valve 44, that is, the upper large diameter portion 442 or the lower large It is blocked by the diameter portion 444. At this time, the fuel oil introduction space 27 has moved to a position where it does not communicate with the fuel injection holes 16a to 16d.

  According to the present embodiment, when the needle valve 26 is opened, the fuel oil introduced from the vertical groove 23 is injected from the fuel injection holes 16 a and 16 b through the fuel oil introduction space 27 of the spool valve 44. At the same time, the fuel oil that has reached the lower space 25 through the fuel supply hole 440 is injected from the fuel injection holes 16 c and 16 d through the space 25 below the spool valve 44.

  On the other hand, when the needle valve 26 is closed, the outer peripheral surfaces (the upper large diameter portion 442 and the lower large diameter portion 444) of the needle valve 26 face the fuel injection holes 16a to 16d, while the fuel oil introduction space 27 has a fuel injection. Since the holes 16a to 16d do not communicate with each other, the injection holes 16a to 16d are not supplied with fuel from the fuel introduction space. Therefore, when the needle valve 26 is closed, the fuel oil accumulated in the fuel oil introduction space 27 does not sag because the fuel oil is supplied to the combustion chamber through the fuel injection holes 16a to 16d.

  The outer peripheral surface 442a of the spool valve 44 located above the fuel oil introduction space 27, that is, the outer peripheral surface 442a of the upper large-diameter portion 442 is always the inner periphery of the center hole 21 of the housing 14 in the opening / closing operation of the needle valve 26. Touching the surface.

  Accordingly, when the outer peripheral surface of the spool valve 44 slides in contact with the inner peripheral surface of the center hole 21 of the housing 14 by the opening / closing operation of the needle valve 26, the outer peripheral surface 442 a of the upper large diameter portion 442 is always in the housing 14. The center hole 21 is in contact with the inner peripheral surface. Further, when the needle valve 26 is opened, fuel oil is introduced from the vertical groove 23 into the fuel oil introduction space 27. As a result, the needle valve 26 is supported by the housing 14 by the outer peripheral surface 442a of the upper large-diameter portion 442 even when the concave fuel oil introduction space 27 is formed in the spool valve 44. The behavior of is stabilized. Moreover, since the outer peripheral surface of the spool valve 44 is always in contact with the inner peripheral surface of the center hole 21 of the housing 14, damage due to repeated contact and non-contact is unlikely to occur.

The fuel oil introduction space 27 is formed in an annular shape on the outer periphery of the spool valve 44 as shown in FIG.
Accordingly, the fuel injection holes 16 a to 16 d are provided in the housing 14 at positions different from the longitudinal grooves 23, and the fuel oil introduction space 27 is formed in an annular shape on the outer periphery of the spool valve 44. However, the flow resistance of the fuel oil from the vertical groove 23 through the injection hole 27 through the fuel oil introduction space 27 is constant regardless of the rotational position of the needle valve 26. That is, even when the needle valve 26 rotates around the axis, the flow resistance of the fuel oil does not change, and the fuel oil can be stably injected.

  On the other hand, without forming the vertical groove 23 in the housing 14, for example, a groove is formed in the shaft of the needle valve 26 along the axial direction, or a through hole is formed in the spool valve 44 in the axial direction. A reference example of supplying fuel to the fuel oil introduction space 27 can be considered. However, in the case of this reference example, the position at which the fuel oil is introduced into the fuel oil introduction space 27 approaches or moves away from the fuel injection holes 16a to 16d according to the rotational position of the needle valve 26. The flow path resistance until injection from the fuel injection holes 16a to 16d changes. On the other hand, in the present embodiment, the position where the fuel oil is introduced into the fuel oil introduction space 27 (the position of the longitudinal groove 23 formed in the housing 14) and the positions of the fuel injection holes 16a to 16d are constant. The flow path resistance does not change.

[Second Embodiment]
Next, with reference to FIGS. 9-14, the fuel-injection apparatus 10 which concerns on 2nd Embodiment of this invention is demonstrated.
In the first embodiment and the present embodiment, the longitudinal grooves are different, and the other configurations are the same, and thus redundant description is omitted.
In the first embodiment described above, the longitudinal groove 23 does not communicate with the space 25 below the spool valve 44 when the needle valve 26 is opened. In this case, the path of fuel oil to the fuel injection holes 16a and 16b in the upper injection hole array A and the path of fuel oil to the fuel injection holes 16c and 16d in the lower injection hole array B are separated. Therefore, the channel resistance is different between the two.

  In the present embodiment, as shown in FIGS. 10 and 14, the longitudinal groove 29 is formed to a position communicating with the space 25 below the spool valve 44 even when the needle valve 26 is opened.

  According to the present embodiment, when the needle valve 26 is opened, the fuel oil introduced from the vertical groove 29 is injected from the upper fuel injection holes 16a and 16b via the fuel oil introduction space 27, and at the same time, the spool valve The fuel is injected from the lower fuel injection holes 16 c and 16 d through the space 25 below the reference numeral 44.

  Since the fuel oil introduction space 27 and the space 25 below the spool valve communicate with each other via a vertical groove 29 formed on the inner peripheral surface of the housing 14, the upper fuel injection holes 16a and 16b and the lower fuel injection holes 16a and 16b are connected to each other. With respect to the fuel oil injected from the fuel injection holes 16c and 16d, the flow path resistance and the injection pressure can be maintained uniformly.

DESCRIPTION OF SYMBOLS 10 Fuel injection apparatus 11 Combustion chamber 12 Cylinder head 14 Housing 16a, 16b, 16c, 16d Fuel injection hole 18, 24 Fuel supply path 23 Vertical groove (groove part)
26 Needle valve 27 Fuel oil introduction space 44 Spool valve

Claims (7)

A housing in which a fuel supply path is formed and a fuel injection hole is formed at the tip;
A needle valve that is disposed inside the housing and opens and closes the fuel supply path in accordance with fuel oil pressure;
A spool valve provided at a tip of the needle valve and having an outer peripheral surface sliding in contact with an inner peripheral surface of the housing;
A groove formed at a position different from the fuel injection hole on the inner peripheral surface of the housing, and communicated with the fuel supply path;
With
A fuel oil introduction space through which fuel oil flows is formed in the spool valve,
When the fuel supply path is opened, the fuel oil introduction space communicates with the groove, and the fuel oil introduction space moves to a position where it communicates with the fuel injection hole.
A fuel injection device in which an outer peripheral surface of the spool valve faces the fuel injection hole and the fuel oil introduction space moves to a position not communicating with the fuel injection hole when the fuel supply path is closed.   2. The fuel injection device according to claim 1, wherein an upper outer peripheral surface of the spool valve is always in contact with an inner peripheral surface of the housing in an opening / closing operation of the fuel supply path.   The fuel injection device according to claim 1 or 2, wherein the fuel oil introduction space is formed in an annular shape by the spool valve. The fuel injection hole is provided with an upper fuel injection hole and a lower fuel injection hole in the housing in the axial direction,
A fuel supply path for supplying fuel to a space below the spool valve is formed inside the spool valve,
When the fuel supply path is opened, the fuel oil introduction space communicates with the groove, and the fuel oil introduction space moves to a position where it communicates with the upper fuel injection hole. The fuel injection device according to any one of claims 1 to 3, wherein a space below the spool valve communicates with the groove and communicates with the lower fuel injection hole.   The said groove part is formed in multiple numbers by the internal peripheral surface of the said housing, The said multiple groove parts are provided in the internal peripheral surface of the said housing at equal intervals. Fuel injection device.   The fuel injection device according to any one of claims 1 to 5, wherein the groove portion and the fuel injection hole are formed at a distance equal to or larger than a diameter of the fuel injection hole.   A diesel engine comprising the cylinder head provided with the fuel injection device according to any one of claims 1 to 6.

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