JPH03117672A - Fuel injection device - Google Patents

Abstract

PURPOSE:To improve the utilization factor of air and to perform stable combustion by a method wherein a plurality of injection nozzle are arranged in a meandering state therebetween along a peripheral direction on the root side and the tip side of the tip part of a fuel injection nozzle. CONSTITUTION:A plurality, for example, four each of injection nozzles 36 and 37 are disposed in a meandering state therebetween on peripheries on the root side and the tip side of the spherical shellform tip part of a fuel injection nozzle body 19. In this case, a diameter D of the injection nozzle 36 on the root side is set to a value higher than a diameter (d) of the injection nozzle 37 on the tip side. When a sheet surface 35 is opened by means of a nozzle needle 34, fuel is sprayed in a dispersed state through the injection nozzles 36 and 37, and the utilization factor of air in a combustion chamber, especially on the bottom thereof, is improved. This constitution simultaneously improves reduction of production of nitrogen oxide and improvement of combustion.

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a fuel injection device, and particularly to a fuel injection device that supplies fuel pressurized by a fuel injection pump to a fuel injection nozzle, and injects the fuel in the form of a mist from the nozzle of the fuel injection nozzle. The present invention relates to a fuel injection device. SUMMARY OF THE INVENTION This invention relates to an improvement in the nozzle at the tip of a hole nozzle used in a direct-injection diesel engine, and the present invention relates to an improvement in the nozzle at the tip of a hole nozzle used in a direct injection diesel engine. A plurality of nozzles are formed, and the nozzles on the base side and the nozzles on the tip side are arranged in a staggered manner, or the diameter of the nozzle on the base side is made larger than the diameter of the nozzle on the tip side. was made,
By directing the fuel spray from each nozzle into the combustion chamber, which is a cavity formed at the top of the piston, air utilization is improved and the production of nitrogen oxides, hydrocarbons, and particulates or black smoke is eliminated. It is designed to hold down.

[Conventional technology]

In a direct injection diesel engine, a fuel injection pump pressurizes the fuel, and the pressurized fuel is supplied to the fuel injection nozzle, and the fuel pressure moves the nozzle needle to atomize the fuel from the nozzle to the top of the piston. The fuel is injected into the combustion chamber of the engine. A hole nozzle used in a direct injection engine has, for example, four nozzles arranged circumferentially at its tip, and a fuel spray is injected from each of these nozzles.

[Problems to be solved by the invention]

Therefore, in a direct-injection diesel engine that injects fuel through a hole nozzle, although the utilization rate of the air in the combustion chamber at the nozzle or its extended position is improved, the air comes into contact with the fuel in the area between the nozzles. The probability is lower. That is, according to the conventional Hall nozzle, the utilization rate of air is low, and combustion occurs locally within the combustion chamber. The combustion part becomes abnormally high temperature, producing nitrogen oxides, and the fuel particles in the center of the spray do not combine with oxygen, which causes hydrocarbons and particulates to be contained in the exhaust gas. It was the cause. The present invention was made in view of these problems, and by improving the air utilization efficiency and performing more stable combustion, the generation of nitrogen oxides, hydrocarbons, particulates, black smoke, etc. The purpose of this invention is to provide a fuel injection device that can suppress all of the following. Means for Solving Problem K] The present invention provides an apparatus in which pressurized fuel is supplied to a fuel injection nozzle by a fuel injection pump, and the fuel is injected from the nozzle of the fuel injection nozzle. A plurality of nozzles are formed along the circumferential direction on each of the base side and the tip side at the tip of the injection nozzle, and the nozzles on the base side and the nozzles on the tip side are arranged in a staggered manner with respect to each other, Alternatively, the diameter of the nozzle on the base side is made larger than the diameter of the nozzle on the tip side.

[Effect]

Therefore, the number of nozzles is greater than in the past, and the air utilization rate is improved by spraying fuel injected from each of the many nozzles. In addition, since combustion occurs in more W4 regions within the combustion chamber at the top of the piston, by eliminating local uneven distribution of combustion, local temperature increases are prevented, thereby suppressing nitrogen oxides. becomes possible. In addition, since combustion can take place over a wider area and air utilization is improved, it is possible to suppress the generation of hydrocarbons, particulates, and black smoke. K Embodiment FIG. 8 shows a diesel engine 10 equipped with a fuel injection device according to an embodiment of the present invention, and a fuel injection pump 11 is attached to the side surface of the cylinder block of this engine 10. There is. The fuel injection pump 11 includes a camshaft 12, and a timer 13 is attached to the camshaft 12 to adjust the timing of fuel injection. Furthermore, the fuel injection pump 11 has a mechanical governor 1.
4 is attached, and the amount of fuel injected at one time is adjusted by this governor 14. Further, each pump unit of the fuel injection pump 11 is connected to a fuel guard nozzle 16 via an injection pipe 15. The fuel injection nozzle 16 is attached to the cylinder head so as to correspond to each cylinder of the engine, and as shown in FIGS. It has a similar structure. A pressure bin 22 is slidably held within the nozzle body 21, and the pressure bin 22 is pressed downward by a pressure spring 23. The upper end of the pressure spring 23 is received by an adjusting screw 24. The upper end of the adjusting screw 24 and the nozzle body 21
A cap nut 25 is screwed onto the portion protruding from the upper end. Further, an off-hollow screw 26 is screwed completely into the threaded hole on the tip side of the cap nut 25. Further, a connecting portion 29 is provided diagonally on the side surface of the nozzle body 21, and a joint 30 is screwed into this connecting portion 29. A through hole passing through the center of the joint 3o communicates with a fuel passage 31 of the nozzle body 21 and a fuel passage 32 of one nozzle body (see FIG. 7). The fuel passage 32 of one nozzle body is a fuel reservoir 33
It is communicated with. A nozzle needle 34 is slidably held in the nozzle body 19, and a conical portion on the tip side thereof is pressed against a sheet surface 35. In the above configuration, the engine 10 shown in FIG.
When the camshaft 12 is rotationally driven by a portion of the output, each plunger of the pump 11 is pushed up in sequence. Note that the injection timing of the fuel injection pump 11 is adjusted by a timer 13, and the injection amount is adjusted by a mechanical governor 14. The fuel pressurized by each plunger of the fuel injection pump 11 is guided from the fuel passage 31 of the nozzle body 21 to the fuel passage 32 of the nozzle body 19 through the joint 30 iJ3 and the connecting portion 29 shown in FIG. The fuel pressure applied to the fuel reservoir 33 pushes the nozzle needle 34 upward. Then, the nozzle needle 34 moves upward while compressing the pressure spring 23 inside the nozzle body 21 via the pressure bin 22. As a result, the conical portion on the distal end side of the nozzle needle 34 is separated from the seat surface 35, and the nozzle openings 36, 37 are opened. Then, the fuel is injected into the cylinder through the injection ports 36 and 37 in the form of a mist. This fuel spray is spontaneously ignited by the heat of the intake air pressurized by the piston and is combusted. Moreover, in this fuel injection device, the tip of the nozzle body 19 of the fuel injection nozzle 16 is shown in FIGS.
As shown in the figure, in addition to the conventional nozzle 36 on the base side, a nozzle 37 on the tip side is provided. Furthermore, these jets 036 and 37 are arranged in a staggered manner. Therefore, the distance between the nozzles 36 and 37 can be made relatively large, resulting in a multi-nozzle hole nozzle. According to the multi-nozzle hole nozzle 16 using such nozzle ports 36, 37, fuel spray is injected from each nozzle port 36, 37 in a staggered manner. Therefore, the air utilization rate is improved and the combustion efficiency is also improved. Furthermore, with the increase in the number of nozzles, the amount of fuel injected from each nozzle 36, 37 decreases, and air utilization efficiency is improved. Therefore, combustion efficiency is improved and localized high temperatures during combustion can be avoided. Therefore, the amount of nitrogen oxides generated during combustion is reduced. Furthermore, since the efficiency of air use is improved, it is also possible to reduce hydrocarbons, particulates, and black smoke. Also, the spout 36
．． 37 are provided on the root side and the tip side of the nozzle body 19, respectively, so that combustion is prevented from occurring locally near the peripheral edge of the combustion chamber of the piston. This makes it possible to prevent cracks at the edges of the combustion chamber. Next, a modification of the above embodiment will be explained with reference to FIGS. 3 to 5. In this modification, at the tip of the nozzle body 19, the base-side nozzle 36 and the distal-side nozzle 37 are shifted from each other in the axial direction, and in addition, the nozzle-like nozzle 4
I try to place them one by one. Moreover, in this modification, the diameter of the nozzle 36 on the base side is set to a larger value than the diameter d of the nozzle 37 on the tip side. FIG. 51 shows an engine incorporating such a hole nozzle 16, in which a piston 41 is slidably held in the cylinder 40, and a piston 41 is slidably held in the cylinder 40.
The upper opening of 0 is closed by a cylinder head 42. An intake boat 43 and an exhaust boat 44 are formed in the cylinder head 42, and these boats 43 and 44 are opened and closed by an intake valve 45 and an exhaust valve 46, respectively. Further, fuel is injected by the fuel injection nozzle 16 held in the cylinder head 42 toward the combustion v47 provided at the top of the piston 41. Moreover, fuel is injected into the side recess 48 of the combustion chamber 47 by the nozzle 36 on the base side, and into the bottom recess 49 by the nozzle 37 at the tip. As described above, in the engine using the nozzle 16 according to this modification, the combustion chamber 47 of the piston 41 is provided with the side recess 48 and the bottom recess 49, and the two-stage combustion chamber 47 is Hall nozzle 16 corresponding to
The shape of the nozzle body 19 is arranged in a staggered manner with a large diameter nozzle 36 on the base side and a small diameter nozzle 37 on the tip side. That is, in addition to the conventional hole nozzle nozzle 36, a small-diameter nozzle 37 is added, which makes it possible to improve the air utilization rate, particularly in the bottom 49 of the combustion chamber 47. Furthermore, since the diameter of the nozzle 47 that injects the fuel spray toward the bottom 49 of the combustion chamber 47 is small, the penetration of the spray is also small, and is approximately the same as the penetration of the spray from the nozzle 36. It has become. The compatibility of reducing exhaust gases, especially nitrogen oxides, with conventional hole nozzles for direct injection diesel engines and improving combustion to overcome them has already reached its limit. In other words, if timing retard is performed by delaying the injection timing in order to reduce nitrogen oxides, combustion will deteriorate and the exhaust gas will contain hydrocarbons, particulates, and black smoke. These contradictory problems can be solved by improving the utilization rate of air in the combustion chamber 47 and improving combustion by using the multi-nozzle hole nozzle 16 according to this modification. [Effects of the Invention] As described above, the first invention forms a plurality of nozzles along the circumferential direction on the root side and the tip side of the tip of the fuel injection nozzle, and also forms a plurality of nozzles on the root side and the nozzle on the root side. The nozzles on the tip side are arranged in a staggered manner. Therefore, the fuel spray is dispersed, air utilization efficiency is improved, and combustion is improved, thereby making it possible to reduce nitrogen oxides and improve combustion at the same time. In addition, the second invention forms jet ports on the root side and the tip side at the tip of the fuel injection nozzle, and
The diameter of the nozzle on the base side is larger than the diameter of the nozzle on the tip side. Therefore, it is possible to effectively utilize the air at the bottom of the combustion chamber formed at the top of the piston to improve combustion, and the penetration rate of the fuel spray injected from the two types of nozzles can be approximately reduced. It becomes possible to do the same. Therefore, even if timing retard is performed to reduce nitrogen oxides, it is possible to prevent deterioration of combustion by improving the air utilization rate.

[Brief explanation of drawings]

FIG. 1 is an enlarged bottom view of the tip of a fuel injection nozzle according to an embodiment of the present invention, FIG. 2 is an enlarged front view of the same, and FIG. 3 is a longitudinal cross-sectional view of a main part of a fuel injection nozzle according to a modification. Figure 4 is a bottom view of the fuel injection nozzle, Figure 5 is a vertical sectional view of the main parts of an engine using this fuel injection nozzle, Figure 6 is a vertical sectional view showing the overall structure of the fuel injection nozzle, and Figure 7 is the same nozzle. Vertical sectional view of main body, No. 8
The figure is a side view of a diesel engine equipped with this fuel injection device. The names of the main parts in the drawings are as follows. 11. 16. 19. 34. 36. 37. 41. 47. 48. 49. ・Fuel injection pump・Fuel injection nozzle・Nozzle body Nozzle needle・Spout (base side)・Spout hole (tip side)・Piston・Combustion Chamber/Side recess/Bottom recess

Claims (1)

[Scope of Claims] 1. In a device that supplies fuel pressurized by a fuel injection pump to a fuel injection nozzle and injects the fuel from the nozzle of the fuel injection nozzle, the tip of the fuel injection nozzle A plurality of nozzles are formed along the circumferential direction on each of the base side and the tip side of the part, and the nozzles on the base side and the nozzles on the tip side are arranged in a staggered manner with respect to each other. fuel injection device. 2. In a device that supplies fuel pressurized by a fuel injection pump to a fuel injection nozzle and injects the fuel from the nozzle of the fuel injection nozzle, the base side and the tip side at the tip of the fuel injection nozzle. 1. A fuel injection device characterized in that a nozzle is formed at each end, and the diameter of the nozzle on the base side is larger than the diameter of the nozzle on the tip side.