JPH078563U - Fuel injection nozzle - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a fuel injection nozzle capable of performing injection while transiently controlling a plurality of injection amount ratios in a single-cycle injection process, controlling combustion temperature, and reducing NOx. A nozzle main body 50 having a seat portion 56 slidably accommodates a needle valve 20 having a tapered portion 24 that abuts against the seat portion, and by sliding the needle valve 20, the fuel of the suck portion 51 It is a fuel injection nozzle that opens and closes the injection hole 52. A first fuel passage 54 for guiding the first fuel is provided upstream of the contact portion between the seat portion 24 and the tapered portion 56, and a second fuel passage for guiding the second fuel is provided in the contact portion. 22 is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fuel injection nozzle mainly used for a diesel engine, and more particularly to a fuel injection nozzle suitable for injecting a plurality of different fuels.

[0002]

[Prior art]

 Conventionally, examples of the invention relating to a fuel injection nozzle for merging different kinds of fuel in the nozzle are disclosed in, for example, Japanese Patent Application Laid-Open No. 62-4570 and Japanese Utility Model Publication No. 3-55812.

That is, Japanese Patent Laid-Open No. 62-4570 discloses that different types of fuel are merged at the upper portion of a so-called nozzle seat portion, and Japanese Utility Model Publication No. 3-55812 discloses a nozzle body. To form a first fuel passage and to form a second fuel passage in the needle valve extending in the axial direction thereof, and further to provide a step at a position adjacent to the tapered portion on the needle valve and It is disclosed that a laterally extending communication passage is formed. These fuel injection nozzles are mainly used for the purpose of isolating the fuel supply system of fuel that easily corrodes the injection device, and injecting fuel in a state in which the fuels are not mixed as much as possible.

By the way, for example, in a fuel injection nozzle of a type that mixes and injects a main fuel such as light oil and an auxiliary fuel such as water, the temperature control in the combustion process such as lowering the combustion temperature in order to reduce NOx. There is a need for possible fuel injection nozzles.

[0005]

[Problems to be solved by the device]

 However, in the conventional fuel injection nozzle as described above, it is not possible to perform an operation of transiently controlling a plurality of injection amount ratios in a single-cycle injection process.

Therefore, there is a problem that the combustion temperature cannot be controlled well and NOx reduction cannot be sufficiently achieved with the conventional structure.

The present invention was created under such circumstances, and an object thereof is to perform injection while transiently controlling a plurality of injection amount ratios in one cycle of the injection process, and to improve combustion temperature. The purpose of the present invention is to provide a fuel injection nozzle capable of controlling the temperature and reducing NOx.

[0008]

[Means for Solving the Problems]

 According to the present invention, a nozzle body having a seat portion accommodates a needle valve having a tapered portion that abuts against the seat portion in a slidable manner, and by sliding the needle valve, a fuel injection hole of a sack portion is formed. In the fuel injection nozzle that opens and closes, a first fuel passage for guiding the first fuel is provided upstream of the contact portion between the seat portion and the taper portion, and the second fuel is guided to the contact portion. A second fuel passage is provided.

[0009]

[Action]

 According to the present invention, when the injection amount of the first fuel (for example, light oil) is J1 and the injection amount of the second fuel (for example, water) is J2, J1 <J 2 at the start of fuel injection. Therefore, the injection amount of water becomes larger than the injection amount of light oil. Next, when the needle valve is fully lifted and enters the state of main injection, J1> J2, contrary to the phenomenon at the start of lift, and the injection amount of light oil becomes larger than the injection amount of water. Then, when the main injection ends, the lift amount of the needle valve decreases, and here J1 <J2 again, and the water injection amount becomes larger than the light oil injection amount.

As described above, when the fuel injection nozzle of the present invention is used, the relationship of J1 <J2 at the start of injection and J1> J2 at the time of main injection and J1 <J2 at the end of injection is satisfied. The injection rate of the second fuel (eg water) in the cycle is transiently controlled.

[0011]

【Example】

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, the fuel injection nozzle 1 includes a nozzle body 50 and a needle valve 20 that is inserted into the nozzle body 50 and functions as a valve.

The nozzle body 50 has a sack portion 51 at its tip, and the sack portion 51 is provided with a plurality of fuel injection holes 52. Further, above the fuel injection hole 52, there is a conical seat portion 56.

Further, in the nozzle body 50, for example, a first fuel passage 54 for passing a first fuel (for example, light oil) sent from the distribution type fuel injection pump 10 is formed in the axial direction. ing.

A fuel pressure of about 200 to 900 Kg / cm 2 is usually applied to the first fuel passage 54.

On the other hand, the needle valve 20, which is inserted into the nozzle body 50 and functions as a valve, is provided with a taper portion 24 that is separable from and in contact with the seat portion 56 for opening and closing the fuel injection hole 52. .

In the needle valve 20, for example, a second fuel passage 22 for passing a second fuel (for example, water) sent from the water pump 12 is formed, and the second fuel passage 22 is formed. Has a body passage 22a extending in the axial direction and a communication hole 22b communicating below the body passage 22a.

The communication hole 22b has a shape that extends laterally toward the taper portion 24 that is separable from and in contact with the seat portion 56 of the nozzle body 50.

A fuel pressure of about 100 kg / cm 2 is normally applied to the second fuel passage 22 as described above at a constant pressure.

As shown in FIG. 2, the conical portion 58 slightly above the seat portion 56 of the nozzle body 50 is not completely in close contact with the tapered portion of the needle valve 20, and a slight gap is formed. It has become so.

The flow passage area of the second fuel passage 22 is set smaller than the total injection hole area of all the fuel injection holes 52. According to this, the backflow of the fuel into the second fuel passage 22 is prevented.

Next, the operation of the fuel injection nozzle 1 of the present invention will be described with reference to FIGS.

FIG. 3A shows a state where the needle valve 20 is seated, that is, a state where the taper portion 24 of the needle valve 20 is in close contact with the sheet portion 56 of the nozzle body 50. From this state, when the first fuel pressure exceeds a certain value, as shown in FIG. 3B, the lift of the needle valve 20 is started and the fuel injection is started.

The relationship between the injection amount J1 of the first fuel (light oil) and the injection amount J2 of the second fuel (water) at this injection start timing is J1 <J2, and the injection amount of water is the injection of light oil. It is in a state of being larger than the quantity.

This is because the outlet of the communication hole 22b of the second fuel passage 22 is closer to the injection hole 52 than the outlet of the first fuel passage 24.

Next, as shown in FIG. 3C, when the needle valve 20 is fully lifted and enters the state of main injection, this time, J1> J2, contrary to the phenomenon at the start of lift, and light oil injection is performed. The amount becomes larger than the water injection amount.

This is because the first fuel pressure is higher than the second fuel pressure, so that the outlet of the communication hole 22b is temporarily blocked by the first fuel pressure.

When the main injection shown in FIG. 3C is completed, the lift state of the needle valve 20 returns to the state shown in FIG. 3B, where J1 <J2 again, and the injection amount of water is light oil. Is greater than the injection amount of. This is because the first fuel pressure drops when the main injection ends.

As described above, by using the fuel injection nozzle of the present invention, it is possible to satisfy the relationship of J1 <J2 at the start of injection, J1> J2 at the main injection, and J1 <J2 at the end of the injection.

As a result, the injection ratio of the second fuel (water) in one cycle can be transiently controlled, and the combustion temperature can be lowered to reduce NOx. In addition, such control can also enable stratified injection of different types of fuel.

[0031]

[Effect of device]

 As described in detail above, the fuel injection nozzle of the present invention is provided with the first fuel passage for guiding the first fuel upstream of the contact portion between the seat portion and the taper portion, and the contact portion has the above-mentioned first fuel passage. Since the second fuel passage that guides the second fuel is provided, the injection rate of the second fuel in one cycle is transiently controlled, so when it is water, it is necessary to reduce NOx. It is possible to lower the combustion temperature.

Further, by such control, if injection of different kinds of fuel is performed, for example, stratified injection can be enabled, and the like.

[Brief description of drawings]

FIG. 1 is a schematic overall view of a fuel injection nozzle of the present invention.

FIG. 2 is an enlarged cross-sectional view in which a portion A which is a tip portion of the nozzle of FIG. 1 is partially enlarged.

3 (a) to 3 (c) are cross-sectional views of a nozzle tip portion for explaining the operation of the fuel injection nozzle of the present invention.

[Explanation of symbols]

 20 Needle valve 22 Second fuel passage 22a Main body passage 22b Communication hole 24 Tapered portion 50 Nozzle body 52 Fuel injection hole 54 First fuel passage 56 Seat portion

Claims (1)

[Scope of utility model registration request] 1. A nozzle body having a seat portion accommodates a needle valve having a taper portion that abuts against the seat portion slidably, and by sliding the needle valve,
In the fuel injection nozzle that opens and closes the fuel injection hole of the sack portion, upstream of the contact portion between the seat portion and the tapered portion,
A fuel injection nozzle comprising a first fuel passage for guiding a first fuel, and a second fuel passage for guiding a second fuel provided at the contact portion.