JP4170344B2 - Fuel injection device for in-cylinder direct injection - Google Patents

Description

  In order to seal high-temperature and high-pressure combustion gas generated in a combustion space of an internal combustion engine, the present invention provides a direct in-cylinder injection provided with a combustion gas seal provided between a fuel injection valve and a fuel injection valve hole. The present invention relates to a fuel injection device.

  2. Description of the Related Art Conventionally, in-cylinder direct injection fuel injection devices that directly inject fuel into a combustion space are provided with a combustion gas seal that seals between a fuel injection valve and a fuel injection valve hole. Is known (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 10-30527

  However, in this case, since the fuel is directly injected into the combustion space from the fuel injection port provided at the tip of the fuel injection valve, the resin combustion gas provided between the fuel injection valve and the fuel injection valve hole The seal comes into contact with high-temperature and high-pressure combustion gas in the combustion space, and the combustion gas seal deteriorates when used for a long period of time. As a result, the sealing effect of the combustion gas seal is reduced.

  An object of the present invention is to solve the above-described problems, and the object of the present invention is to reduce the contact with high-temperature and high-pressure combustion gas, thereby reducing deterioration of the combustion gas seal, A fuel injection device for direct in-cylinder injection that can maintain the sealing effect of the combustion gas seal is provided.

The fuel injection system for a cylinder direct injection according to the present invention is inserted into a hole for the fuel injection valve formed in d Njinheddo, through the fuel injection port provided at the distal end portion, directly injecting fuel into a combustion space And a combustion gas seal that is provided between the fuel injection valve hole and the fuel injection valve and seals between the fuel injection valve hole and the fuel injection valve to seal combustion gas A fuel injection device for in-cylinder direct injection having at least one of the opposed fuel injection valve hole and the fuel injection valve between the fuel injection port and the combustion gas seal, Flow resistance increasing means for increasing the flow resistance of the fuel flowing from the combustion space toward the combustion gas seal is provided, and the flow resistance increasing means is a plurality of dents.

  According to the in-cylinder direct injection fuel injection device according to the present invention, the deterioration of the combustion gas seal can be reduced by reducing the contact with the high-temperature and high-pressure combustion gas, and the sealing effect of the combustion gas seal can be maintained. it can.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding members and parts are denoted by the same reference numerals.
Embodiment 1 FIG.
FIG. 1 is a cross-sectional view of the fuel injection device for direct injection in a cylinder according to Embodiment 1 when the first spiral groove and the second spiral groove are omitted, and FIG. 2 is a fuel injection valve hole 2 in FIG. FIG. 6 is an enlarged cross-sectional view when the first spiral groove 7 is formed and the second spiral groove 8 is formed in the fuel injection valve 4.

A fuel injection valve hole 2 is formed in the engine head 1 of the fuel injection device for in-cylinder direct injection. A fuel injection valve 4 for directly injecting fuel into the combustion space 3 is inserted into the fuel injection valve hole 2.
A fuel injection port 5 through which fuel is injected is formed at the tip of the fuel injection valve 4. Also, a ring-shaped seal is provided between the fuel injection valve hole 2 and the fuel injection valve 4 to seal between the fuel injection valve hole 2 and the fuel injection valve 4 and seal the combustion gas in the combustion space 3. A combustion gas seal 6 is provided.

A second spiral groove 8 is formed on the outer peripheral surface of the fuel injection valve 4 facing the fuel injection valve hole 2 so as to communicate with the combustion space 3 from the end surface of the fuel injection port 5 to the combustion gas seal 6. .
A first spiral groove 7 corresponding to the second spiral groove 8 is formed on the inner peripheral surface of the fuel injection valve hole 2 facing the fuel injection valve 4.
The spiral directions of the first spiral groove 7 and the second spiral groove 8 are opposite to each other.
The first spiral groove 7 and the second spiral groove 8 respectively constitute flow resistance increasing means for increasing the flow resistance of the fuel gas flowing from the combustion space 3 toward the combustion gas seal 6.

  The depth of the first spiral groove 7 and the second spiral groove 8 is about several hundred μm.

  The engine head 1 facing the combustion space 3 near the fuel injection port 5 is provided with a spark plug 9 for igniting the fuel in the combustion space 3.

Next, the operation of the in-cylinder direct injection fuel injection device according to Embodiment 1 will be described.
In an internal combustion engine that performs combustion by directly injecting fuel into the combustion space 3 using the fuel injection valve 4, a process of sucking air into the combustion space 3, and air sucked into the combustion space 3 with a piston (not shown). The fuel is injected from the fuel injection valve 4 in the compression stroke, and the fuel evaporated by the discharge energy of the spark plug 9 is ignited.

When the air and fuel in the combustion space 3 change to high-temperature and high-pressure combustion gas due to ignition, the high-temperature and high-pressure combustion gas in the combustion space 3 flows into the gap space between the fuel injection valve hole 2 and the fuel injection valve 4.
As a result, the combustion gas flows into the first spiral groove 7 and the second spiral groove 8 from the combustion space 3, and the swirl force acts on the combustion gas by the first spiral groove 7 and the second spiral groove 8. .

  Normally, when a swirl force acts on the gas, initially, the flow is disturbed and the flow resistance is increased. However, when the vortex or the like that becomes the flow resistance is stabilized, the flow resistance is decreased and a smooth flow is achieved. On the other hand, when the flow changes at a high speed cycle as in the internal combustion engine (when the shaft speed is 3000 rpm, the combustion gas is changed 25 times per second), the flow resistance is generated when the gas is disturbed. And the gas flow direction is changed again before shifting to a smooth flow. As a result, disturbance is always generated, and the flow resistance is increased.

  From this, a high flow resistance acts on the combustion gas flowing into the first spiral groove 7 and the second spiral groove 8, and there is a time delay until the high-temperature and high-pressure combustion gas reaches the combustion gas seal 6. In the meantime, the pressure of the combustion gas in the combustion space 3 starts to decrease, and the combustion gas is drawn back to the combustion space 3 again before reaching the combustion gas seal 6 sufficiently.

  As described above, according to the fuel injection device for in-cylinder direct injection according to the first embodiment, the fuel injection valve hole 2 and the fuel injection that face each other between the fuel injection port 5 and the combustion gas seal 6 are provided. Since the first spiral groove 7 and the second spiral groove 8 are formed in the valve 4 so as to communicate with the combustion space 3, the high temperature that flows between the fuel injection valve hole 2 and the fuel injection valve 4. The flow of high-pressure combustion gas is disturbed to increase the flow resistance, the amount of high-temperature and high-pressure combustion gas reaching the combustion gas seal 6 is reduced, the deterioration of the combustion gas seal 6 is reduced, and the combustion gas seal 6 The sealing effect can last.

  In addition, since the first spiral groove 7 and the second spiral groove 8 have both spiral directions opposite to each other, the high-temperature and high-pressure flowing between the fuel injection valve hole 2 and the fuel injection valve 4. The combustion gas flow is further disturbed to increase the flow resistance, the amount of high-temperature and high-pressure combustion gas reaching the combustion gas seal 6 is reduced, the deterioration of the combustion gas seal 6 is reduced, and the combustion gas is reduced. The sealing effect of the seal 6 can be sustained.

FIG. 3 is a cross-sectional view of the main part showing another example of the direct-injection fuel injection device according to the first embodiment.
In the fuel injection device for in-cylinder direct injection, the fuel injection valve hole 2 is not formed with the first spiral groove 7, and the fuel injection valve 4 is formed with the second spiral groove 8. .
Other configurations are the same as those of the first embodiment.

  According to the fuel injection device for in-cylinder direct injection, since only the second spiral groove 8 has to be formed, processing becomes easy.

FIG. 4 is a cross-sectional view of the main part showing another example of the direct-injection fuel injection device according to the first embodiment.
In this direct injection fuel injection device, the first spiral groove 7 is formed in the fuel injection valve hole 2, and the second spiral groove 8 is not formed in the fuel injection valve 4. .
Other configurations are the same as those of the first embodiment.

  According to the fuel injection device for in-cylinder direct injection, since only the first spiral groove 7 has to be formed, processing becomes easy.

  In the in-cylinder direct injection fuel injection device having the above configuration, the first spiral groove 7 and the second spiral groove 8 communicate with the combustion space 3 and are formed from the end face of the fuel injection port 5 to the combustion gas seal 6. However, the present invention is not limited to this, and the flow resistance is higher at the inflow portion of the combustion gas, so that it may be formed only in the vicinity of the combustion space 3.

  Further, in the in-cylinder direct injection fuel injection device having the above-described configuration, the depths of the first spiral groove 7 and the second spiral groove 8 may be made shallower as they approach the combustion gas seal 6. Good.

Embodiment 2. FIG.
FIG. 5 is an enlarged cross-sectional view when the first dent 10 and the second dent 11 of the direct-injection fuel injection device according to the second embodiment are formed.

A plurality of first recesses 10 are formed from the combustion space 3 to the combustion gas seal 6 on the inner peripheral surface of the fuel injection valve hole 2 facing the fuel injection valve 4.
On the other hand, a plurality of second recesses 11 are formed on the outer peripheral surface of the fuel injection valve 4 facing the fuel injection valve hole 2 from the end surface of the fuel injection port 5 to the combustion gas seal 6.
Since the first dent 10 and the second dent 11 are arranged away from each other along the axial direction and the circumferential direction of the fuel injection valve 4, only the second dent 11 is shown in FIG. The first recess 10 is not shown.
The first recess 10 and the second recess 11 constitute a flow resistance increasing means.

The depth of the first dent 10 and the second dent 11 is about several hundred μm.
Other configurations are the same as those of the first embodiment.

Next, the operation of the in-cylinder direct injection fuel injection device according to Embodiment 2 will be described.
The process is the same as in the first embodiment until the air and fuel in the combustion space 3 are changed to high-temperature and high-pressure combustion gas.

First, as shown in FIG. 6, the high-temperature and high-pressure combustion gas in the combustion space 3 flows into the gap space 12 between the fuel injection valve hole 2 and the fuel injection valve 4.
Next, since the flow 13 of the combustion gas flowing into the gap space 12 is fast, the combustion gas flow 13 remains in the second recess 11 when passing the side of the second recess 11 according to Bernoulli's theorem. Aspirate the combustion gas.
Further, the suction of the combustion gas causes the downstream combustion gas to be drawn into the decompressed second recess 11, and the combustion gas flow 13 in the vicinity of the second recess 11 is a streamline along the second recess 11. It becomes.
As a result, a vortex 14 is generated in the vicinity of the downstream portion of the second recess 11 in the combustion gas flow 13, and a vortex 15 is generated on the side opposite to the second recess 11 in the combustion gas flow 13.

  The flow resistance of the combustion gas flow 13 is increased by the vortices 14 and 15, and a time delay occurs until the high-temperature and high-pressure combustion gas reaches the combustion gas seal 6, during which the pressure of the combustion gas in the combustion space 3 is increased. Since it begins to fall, the combustion gas is drawn back into the combustion space 3 again before reaching the combustion gas seal 6 sufficiently.

  As described above, according to the fuel injection device for direct in-cylinder injection according to the second embodiment, the fuel injection valve hole 2 and the fuel injection that face each other between the fuel injection port 5 and the combustion gas seal 6. Since the valve 4 is formed with a plurality of first recesses 10 and second recesses 11, the flow of high-temperature and high-pressure combustion gas flowing between the fuel injection valve hole 2 and the fuel injection valve 4. 13 is disturbed to increase the flow resistance, the amount of high-temperature and high-pressure combustion gas reaching the combustion gas seal 6 is reduced, the deterioration of the combustion gas seal 6 is reduced, and the sealing effect of the combustion gas seal 6 is maintained. be able to.

In addition, as shown in FIG. 7, the 1st dent 10 and the 2nd dent 11 may be arrange | positioned facing each other.
In this case, the vortex 14 of the combustion gas flow 13 is generated in the vicinity of the downstream portion of the first dent 10 and the second dent 11 so as to sandwich the combustion gas flow 13. Further, in the vicinity of the center between the first recess 10 and the second recess 11, a vortex 15 in which the vortex caused by the first recess 10 and the vortex caused by the second recess 11 collide with each other is generated.

  According to this direct injection fuel injection device, since the first recess 10 and the second recess 11 face each other, the high temperature flowing between the fuel injection valve hole 2 and the fuel injection valve 4. The flow 13 of the high-pressure combustion gas is further disturbed to increase the flow resistance, the amount of the high-temperature and high-pressure combustion gas reaching the combustion gas seal 6 is reduced, the deterioration of the combustion gas seal 6 is reduced, The sealing effect of the combustion gas seal 6 can be further maintained.

Moreover, as shown in FIG. 8, the 1st dent 10 and the 2nd dent 11 may be arrange | positioned mutually shifted | deviated to the axial direction of the fuel injection valve 4. As shown in FIG.
In this case, a vortex 14 of the combustion gas flow 13 is generated near the downstream portion of the second recess 11, and a vortex 15 is generated on the side of the combustion gas flow 13 opposite to the first recess 10. Furthermore, the vortices 14 and 15 are also affected by the first recess 10 and become larger vortices.

  According to the fuel injection device for direct injection in a cylinder, since the first recess 10 and the second recess 11 are displaced in the axial direction of the fuel injection valve 4, the fuel injection valve hole 2 and The flow 13 of the high-temperature and high-pressure combustion gas flowing into the fuel injection valve 4 is further disturbed to increase the flow resistance, and the amount of the high-temperature and high-pressure combustion gas reaching the combustion gas seal 6 is reduced. The deterioration of the combustion gas seal 6 is reduced, and the sealing effect of the combustion gas seal 6 can be further maintained.

FIG. 9 is a cross-sectional view showing another example of the direct-injection fuel injection device according to the second embodiment.
In this in-cylinder direct injection fuel injection device, the first recess 10 is not formed in the fuel injection valve hole 2, and the second recess 11 is formed in the fuel injection valve 4.
Other configurations are the same as those of the second embodiment.

  According to the fuel injection device for in-cylinder direct injection, since only the second recess 11 has to be formed, processing becomes easy.

FIG. 10 is an enlarged cross-sectional view showing still another example of the direct-injection fuel injection device according to the second embodiment.
In this direct injection fuel injection device, the fuel injection valve hole 2 is formed with a first recess 10, and the fuel injection valve 4 is not formed with a second recess 11.
Other configurations are the same as those of the second embodiment.

  According to the fuel injection device for in-cylinder direct injection, since only the first recess 10 needs to be formed, the processing becomes easy.

  In the fuel injection device for direct injection in a cylinder having the above configuration, the first recess 10 and the second recess 11 are described as being formed from the end face of the fuel injection port 5 to the combustion gas seal 6. The flow resistance is not limited to this, and the flow resistance becomes higher at the inflow portion of the combustion gas, so that it may be formed only in the vicinity of the combustion space 3.

  Further, in the fuel injection device for in-cylinder direct injection having the above-described configuration, the depth of the first recess 10 and the second recess 11 may be made shallower as the combustion gas seal 6 is approached.

It is sectional drawing when the 1st spiral groove and 2nd spiral groove of the fuel-injection apparatus for cylinder direct injection which concern on Embodiment 1 are abbreviate | omitted. FIG. 3 is an enlarged view of a main part when a first spiral groove is formed in the fuel injection valve hole of FIG. 1 and a second spiral groove is formed in the fuel injection valve. FIG. 6 is a cross-sectional view of a main part showing another example of the direct fuel injection device for direct injection according to the first embodiment. FIG. 6 is a cross-sectional view of a main part showing still another example of the fuel injection device for in-cylinder direct injection according to the first embodiment. It is principal part sectional drawing when the 1st dent and 2nd dent of the fuel injection device for cylinder direct injection concerning Embodiment 2 are formed. It is sectional drawing which showed the 2nd dent of FIG. 5, and the side surface of the hole for fuel injection valves. It is sectional drawing when the 1st dent of FIG. 5 and the 2nd dent are facing. It is sectional drawing when the 1st dent of FIG. 5 and the 2nd dent are arrange | positioned mutually shifted | deviated. FIG. 6 is a cross-sectional view of a main part showing another example of a direct injection fuel injection device according to Embodiment 2. FIG. 10 is a cross-sectional view of a main part showing still another example of a fuel injection device for direct in-cylinder injection according to Embodiment 2.

Explanation of symbols

  1 Engine Head, 2 Fuel Injection Valve Hole, 3 Combustion Space, 4 Fuel Injection Valve, 5 Fuel Injection Port, 6 Combustion Gas Seal, 7 First Spiral Groove, 8 Second Spiral Groove, 9 Spark Plug, 10 First 1 dent, 11 second dent, 12 gap space, 13 combustion gas flow, 14 vortex, 15 vortex.

Claims (3)

A fuel injection valve that is inserted into a fuel injection valve hole formed in the engine head and directly injects fuel into the combustion space via a fuel injection port provided at the tip;
A combustion gas seal provided between the fuel injection valve hole and the fuel injection valve, sealing between the fuel injection valve hole and the fuel injection valve and sealing combustion gas;
In-cylinder direct injection fuel injection device having
The flow of the fuel that is provided in at least one of the fuel injection valve hole and the fuel injection valve facing each other between the fuel injection port and the combustion gas seal and flows from the combustion space toward the combustion gas seal Comprising flow resistance increasing means for increasing resistance;
The in-cylinder direct injection fuel injection device, wherein the flow resistance increasing means is a plurality of indentations. The in-cylinder direct injection fuel injection device according to claim 1 , wherein the recess is formed in both the fuel injection valve hole and the fuel injection valve, and both the recesses face each other. . The indentations, wherein are formed on both of the fuel injection valve hole and the fuel injection valve, according to claim 1, characterized in that both said recess is arranged offset in the axial direction of the fuel injection valve In-cylinder direct injection fuel injection device.

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