JP2006037861A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device realizing both functions of ejecting fuel to the specific area of a combustion chamber and uniformly ejecting fuel to the combustion chamber, and having no difficulty in machining. <P>SOLUTION: A side directed to the combustion chamber (2) of a fuel port (21) storing pressurized fuel is opened/closed as a fuel outlet by a mushroom valve (12) reciprocated by a solenoid (15). A shroud (30) is provided to the mushroom valve in the fuel port, and the shroud is attached to a shroud driving shaft (32) reciprocated by the solenoid (35) through an arm (31). When performing stratified burning, the shroud approaches the back surface (12a) of the mushroom valve when the mushroom valve is opened, and fuel is ejected toward an ignition plug (3) from a part on a side opposite to the shroud in a clearance between the fuel outlet and the mushroom valve. When performing uniform burning, the shroud is separated from the mushroom valve, and fuel is ejected from the whole of the clearance between the fuel outlet and the mushroom valve. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel injection device, and more particularly to a fuel injection device for an in-cylinder direct injection type spark ignition internal combustion engine.

  In-cylinder direct injection type spark ignition internal combustion engines have been developed. An in-cylinder direct injection type engine is intended to enable stratified combustion, but does not always perform stratified combustion, and stratified combustion is performed under certain operating conditions and uniform combustion is performed under certain operating conditions. In stratified combustion, it is necessary to inject fuel into a specific region in the cylinder, and in uniform combustion, it is necessary to inject fuel evenly into the cylinder. Therefore, the fuel injection device used in such a direct injection type spark ignition internal combustion engine injects fuel into a specific region in the cylinder and injects fuel evenly into the cylinder. Both functions are required.

  Therefore, in the fuel injection device of Patent Document 1, a needle valve whose tip shape is formed asymmetrically with respect to the central axis is rotated to change the fuel injection direction to achieve the above two injections. Further, in the fuel injection device of Patent Document 2, a member for controlling the flow of fuel is disposed between the outer peripheral surface of the shaft portion of the needle valve and the inner peripheral surface of the passage in the valve body in which the needle valve reciprocates. The above two injections are realized by moving this member in the axial direction.

  The fuel injection devices of the above-mentioned Patent Document 1 and Patent Document 2 are both needle-valve type and have a large axial velocity component of the injected fuel, and can realize the fuel injection as desired. As a result, there is a problem that desired combustion cannot be obtained. In addition, there is a problem that very precise processing is required and the manufacturing cost is high.

JP 2000-205088 A JP 2001-107823 A

  In view of the above problems, the present invention provides a fuel injection device that can realize both functions of injecting fuel into a specific region of a combustion chamber and injecting fuel evenly into the combustion chamber and is not difficult to process. The purpose is to do.

According to the invention of claim 1, a fuel injection device for injecting fuel into a combustion chamber of a direct injection type internal combustion engine,
An umbrella valve is placed outside the fuel outlet facing the combustion chamber of the fuel port where the pressurized fuel is stored, and the umbrella valve is moved away from the fuel outlet and the fuel is released from the gap between the fuel outlet and the umbrella valve when the valve is opened. Which injects
A shroud is provided in the fuel port that can approach and separate the umbrella valve;
When performing stratified combustion, the shroud is brought close to the umbrella valve when the umbrella valve is opened, and fuel is injected only from a part of the gap between the fuel outlet and the umbrella valve,
When performing uniform combustion, when the umbrella valve is opened, the shroud is separated from the umbrella valve and fuel is injected from the entire gap between the fuel outlet and the umbrella valve.
A fuel injection device is provided.

  In the fuel injection device configured as described above, when performing stratified combustion, the shroud approaches the umbrella type valve when the umbrella type valve is opened, and fuel is injected only from a part of the gap between the fuel outlet and the umbrella type valve. When combustion is performed, the shroud is separated from the umbrella valve when the umbrella valve is opened, and fuel is injected from the entire gap between the fuel outlet and the umbrella valve.

  According to the invention of claim 2, in the invention of claim 1, when the internal combustion engine has a spark plug and stratified combustion is performed, a shroud is provided so that fuel is injected toward the spark plug. A fuel injection device is provided.

According to the invention of claim 3, in the fuel injection device for injecting fuel into the combustion chamber of the direct ignition type spark ignition internal combustion engine,
An umbrella valve is placed outside the fuel outlet facing the combustion chamber of the fuel port where the pressurized fuel is stored, and the umbrella valve is moved away from the fuel outlet and the fuel is released from the gap between the fuel outlet and the umbrella valve when the valve is opened. Which injects
The umbrella-type valve is rotatable, and a shroud that partially restricts the fuel injected from the gap between the fuel outlet and the umbrella-type valve is attached to the back surface of the umbrella-type valve facing the fuel outlet side,
When performing stratified combustion, fuel is injected only in a certain direction without rotating the umbrella valve when opening and closing the umbrella valve.
When performing uniform combustion, rotate the umbrella valve when opening and closing the umbrella valve to inject fuel in multiple directions.
A fuel injection device is provided.

  When performing stratified combustion in the fuel injection device configured in this way, the umbrella valve is not rotated when the umbrella valve is opened and closed, so the position of the shroud is fixed and fuel is injected only from a certain direction, and when performing uniform combustion, When the umbrella-type valve is opened and closed, the umbrella-type valve is rotated to change the position of the shroud, so that fuel is injected.

  According to the invention of claim 4, in the invention of claim 3, when the internal combustion engine has a spark plug and performs stratified combustion, the position of the umbrella valve in the rotational direction is such that fuel is injected toward the spark plug. A fuel injection device is provided.

According to the invention described in each claim, fuel is injected only in a certain direction when performing stratified combustion, and fuel is injected in multiple directions when performing uniform combustion.
Further, since the fuel hits the back of the valve umbrella and changes its direction greatly, the speed component in the axial direction of the injected fuel is reduced, which is good for atomization. Also, since there are no needles or nozzle holes that require extremely precise processing, processing is relatively easy.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram showing the structure of the fuel injection device 100 according to the first embodiment of the present invention in a state where fuel is not injected. The fuel injection device 1 has a valve 10, and the valve 10 is formed by attaching an umbrella portion 12 to one end of a valve rod 11. An end flange 13 is attached to the other end of the valve stem 11, and an intermediate flange 14 is attached to the intermediate portion. A solenoid 15 is disposed around the end flange 13.
The fuel injection device 100 is disposed inside the cylinder head 1 of the engine, and the umbrella portion 12 of the valve 10 is exposed in the combustion chamber 2. An ignition plug 3 is attached to the combustion chamber 2 as shown.

  Reference numeral 20 indicates a fuel port block. A fuel port 21 for temporarily storing fuel is formed in the fuel port block 20. The fuel port 21 is supplied with pressurized fuel from a fuel pump (not shown) via a fuel pipe 24. The lower side of the fuel port 21 in the figure is opened and serves as a fuel outlet. The fuel outlet is opened and closed by the umbrella 12 of the valve 10 from the outside. When the valve is closed, the rear surface 12a of the umbrella portion 12 is in contact with the valve seat 23 provided on the first surface 22 (lower surface in the drawing) of the fuel port block 20 in a ring shape along the fuel outlet.

A valve return spring 16 is disposed between the second surface 25 (upper surface in the drawing) of the fuel port block 20 and the intermediate flange 14 of the valve 10, and the valve return spring 16 always causes the valve 10 to move upward in the drawing. That is, it is biased in the closing direction.
When the solenoid 15 is energized, the valve 10 moves downward in the figure against the valve return spring 16. As a result, the back surface 12a of the umbrella portion 12 of the valve 10 is separated from the valve seat 23, and fuel is injected from a gap formed therebetween.

  A shroud 30 is disposed in the fuel port 21. The shroud 30 is attached to a shroud drive shaft 32 via an arm 31. 2 is a cross-sectional view taken along line II-II in FIG. As shown in FIG. 2, the shroud 30 has a semi-cylindrical shape and is formed so as to surround the periphery of the valve stem 11 over a substantially half circumference.

  The shroud drive shaft 32 extends in the vertical direction in the figure in parallel with the valve stem 11. The lower half of the shroud drive shaft 32 is in the fuel port block 20 along with the arm 31, while the upper half is above the fuel port block 20. An end flange 33 is provided at the upper end of the shroud drive shaft 32 in the drawing, and an intermediate flange 34 is provided below the end flange 33. A solenoid 35 is disposed around the end flange 33.

  A shroud return spring 36 is disposed between the intermediate flange 34 and the upper surface 25 of the fuel port block 20. The shroud return spring 36 always urges the shroud 30 upward in the figure. When the solenoid 35 is energized, the shroud drive shaft 32 moves downward in the figure against the shroud return spring 36.

A space larger than the volume of the arm 31 is formed around the arm 31 (including the lower portion of the shroud drive shaft 32) so that the arm 31 can move. Therefore, measures are taken so that the fuel in the fuel port 21 flows into this space and the fuel does not leak through the clearance around the shroud drive shaft 32.
First, a seal member 37 is provided on the fuel port block 20 around the drive shaft 32.

And the shroud 30 is also formed as follows.
The shroud 30 is extended below the lower surface of the arm 31 so as to be larger than the axial dimension of the space formed below the arm 31 when the arm 31 is positioned at the uppermost position in the figure. The shroud 30 is extended above the upper surface of the arm 31 so that it is larger than the axial dimension of the space formed above the arm 31 when the arm 31 is positioned at the lowest position in the figure.

The engine to which the fuel injection device 100 configured as described above is attached performs stratified combustion and uniform combustion according to operating conditions.
FIG. 3A shows a case where the fuel injection device 100 of FIG. 1 injects fuel toward the spark plug 3 in order to cause stratified combustion. The solenoid 15 is energized and the valve 10 is pushed downward in the figure, and a ring-shaped gap is formed between the back surface 12a of the umbrella portion 12 and the valve seat 23. On the other hand, the solenoid 35 is energized and the shroud 30 is also pushed downward in the figure.

As a result, the fuel is blocked by the shroud 30 and almost no fuel is injected from the gap on the shroud 30 side, and most of the fuel is injected from the gap on the valve rod 11 opposite to the shroud 30. In other words, when it is desired to inject fuel in a specific direction, the shroud 30 may be disposed on the opposite side of the valve rod 11 from the direction of injection.
In this embodiment, it is desired to inject fuel toward the spark plug 3. Therefore, as shown in FIG. 2, the shroud 30 is disposed on the opposite side of the valve plug 11 from the position P of the spark plug 3.

  On the other hand, FIG. 3B shows a case where fuel is injected to perform uniform combustion. In this case, of course, the solenoid 15 is energized and the valve 10 is pushed downward in the figure to form a ring-shaped gap between the back surface 12a of the umbrella 12 and the valve seat 23, but the solenoid 35 is de-energized. The shroud 30 is pushed upward in the figure. As a result, the fuel is injected substantially uniformly from the above-described ring-shaped gap.

In both cases (A) and (B) of FIG. 3, the fuel hits the back surface 12 a of the umbrella portion 12 of the valve 10 and is greatly changed in direction, and the velocity component in the axial direction is small and atomized well. Fuel injection can be obtained.
In addition, since the fuel injection device 100 according to the first embodiment is a so-called outer valve-opening type, high accuracy as required for the devices of Patent Documents 1 and 2 is not required in the manufacture thereof.

Next, a second embodiment will be described.
FIG. 4 is a diagram showing the structure of the fuel injection device 200 according to the second embodiment. The valve 10 of the fuel injection device 200 of the second embodiment has the same valve stem 11, the umbrella part 12, the first flange 13, and the second flange 14 as those of the first embodiment. A pinion 17 is attached to the outer side (upper side in the figure) of one flange 13. A rack 18 that meshes with the pinion 17 is provided, and the rack 18 is moved in the left-right direction in the drawing by a rack driving device 19.

  A fuel port 21 for temporarily storing fuel is formed in the fuel port block 20 as in the first embodiment, but a shroud as in the first embodiment is not provided. Instead, a shroud 30 ′ is attached to the back surface 12 a of the umbrella portion 12 of the valve 10.

The fuel injection device 200 of the second embodiment also performs stratified combustion and uniform combustion according to operating conditions.
When performing stratified combustion, the angular position of the valve 10 is fixed so that the shroud 30 ′ is on the opposite side of the direction in which fuel is to be injected (the direction of the spark plug 3), and the solenoid 15 is energized. As described above, when the solenoid 15 is energized, the valve 10 is pushed downward in the drawing, and a gap is formed between the back surface 12a of the umbrella 12 and the valve seat 23, and fuel is injected from this gap.

  However, in the range where the shroud 30 ′ is provided, the shroud 30 ′ serves as a baffle plate, and fuel is injected from the range where the shroud 30 ′ on the opposite side with respect to the shroud 30 ′ and the valve shaft 11 is not provided. That is, when it is desired to inject fuel in a specific direction, the rack drive device 18 may be adjusted so that the shroud 30 ′ is located on the opposite side of the valve rod 11. In this case, since the fuel is desired to be injected toward the spark plug 3, the position of the shroud 30 ′ is such that the shroud 30 ′ is opposite to the spark plug 3 with respect to the valve shaft 11 as shown in FIG. It is determined.

  On the other hand, FIG. 6B shows a case where uniform combustion is performed, and the valve shaft 11 is rotated as the valve 10 moves up and down. When the valve shaft 11 rotates, the angular position of the shroud 30 ′ rotates accordingly, and is injected over a wide range. In the figure, the valve shaft 11 is rotated 360 degrees, and accordingly, fuel is injected in all directions.

  The second embodiment can obtain the same effects as those of the first embodiment. In particular, since the structure is simpler than in the first embodiment, it can be manufactured more easily than in the first embodiment.

  The present invention can be applied to a direct injection type internal combustion engine.

It is a figure which shows the structure of 1st Embodiment of the fuel-injection apparatus of this invention. It is sectional drawing seen along the II-II line of FIG. The figure explaining the action | operation of 1st Embodiment shows the case where (A) the fuel is injected toward a spark plug for stratified combustion. (B) The case where fuel is injected in multiple directions for uniform combustion is shown. It is a figure which shows the structure of 2nd Embodiment of the fuel-injection apparatus of this invention. It is sectional drawing seen along the VV line of FIG. The figure explaining the action | operation of 2nd Embodiment shows the case where (A) the fuel is injected toward a spark plug for stratified combustion. (B) The case where fuel is injected in multiple directions for uniform combustion is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Valve 11 Valve shaft 12 Umbrella part 15 Solenoid 17 Pinion 18 Rack 19 Rack drive device 20 Fuel port block 21 Fuel port 30 Shroud (1st Embodiment)
30 'shroud (second embodiment)
31 Arm 35 Solenoid

Claims (4)

A fuel injection device for injecting fuel into a combustion chamber of an in-cylinder direct injection type internal combustion engine,
An umbrella valve is placed outside the fuel outlet facing the combustion chamber of the fuel port where the pressurized fuel is stored, and the umbrella valve is moved away from the fuel outlet and the fuel is released from the gap between the fuel outlet and the umbrella valve when the valve is opened. Which injects
A shroud is provided in the fuel port that can approach and separate the umbrella valve;
When performing stratified combustion, the shroud is brought close to the umbrella valve when the umbrella valve is opened, and fuel is injected only from a part of the gap between the fuel outlet and the umbrella valve,
When performing uniform combustion, when the umbrella valve is opened, the shroud is separated from the umbrella valve and fuel is injected from the entire gap between the fuel outlet and the umbrella valve.
The fuel-injection apparatus characterized by the above-mentioned. The internal combustion engine has a spark plug,
The fuel injection device according to claim 1, wherein a shroud is provided so that fuel is injected toward the spark plug when performing stratified combustion. A fuel injection device for injecting fuel into a combustion chamber of an in-cylinder direct injection type spark ignition internal combustion engine,
An umbrella valve is placed outside the fuel outlet facing the combustion chamber of the fuel port where the pressurized fuel is stored, and the umbrella valve is moved away from the fuel outlet and the fuel is released from the gap between the fuel outlet and the umbrella valve. Which injects
The umbrella-type valve is rotatable, and a shroud that partially restricts the fuel injected from the gap between the fuel outlet and the umbrella-type valve is attached to the back surface of the umbrella-type valve facing the fuel outlet side,
When performing stratified combustion, fuel is injected only in a certain direction without rotating the umbrella valve when opening and closing the umbrella valve.
When performing uniform combustion, rotate the umbrella valve when opening and closing the umbrella valve to inject fuel in multiple directions.
The fuel-injection apparatus characterized by the above-mentioned. The internal combustion engine has a spark plug,
The fuel injection device according to claim 1, wherein the rotational direction position of the umbrella valve is determined so that fuel is injected toward the spark plug when stratified combustion is performed.

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