JPS6318025B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in fuel injection valves for direct injection internal combustion engines.

In conventional fuel injection valves of this kind, in order to optimize the shape of the combustion chamber, the strength of the nozzle part was considered, and as a result, the nozzles were arranged in multiple rows, and the number of nozzles in each row was different. be.

The tip of a conventional fuel injection valve of this type is shown in FIGS. 1 and 2. In the figure, 01 is a fuel injection valve, 02 is a nozzle in the upstream nozzle array α, and 03 is a nozzle in the downstream nozzle array β. As shown in FIG. 2, the nozzles 02 were arranged at a pitch of 90° in the circumferential direction, and the nozzles 03 were arranged at a pitch of p in the circumferential direction, both of which were equally spaced.

For this reason, the arrangement of the spray in the fuel chamber space becomes uneven, the air utilization rate during combustion is not optimal, and there is room for improvement in the combustion performance of the fuel injection valve.

An object of the present invention is to provide a fuel injection valve that can improve combustion performance by paying attention to the above points, and is characterized in that the upper nozzle openings are arranged at equal pitches in the cross-sectional projection of the fuel injection valve. The pitch of the lower nozzles is unequal, and the axes of the nozzles do not overlap.

In this case, it is possible to maximize the solid angle of the spray or flame group between the combustion chambers and minimize mutual overlap or interference, thereby improving air utilization during combustion and improving combustion.

Examples according to the present invention will be described below.

3 is a cross-sectional view showing the tip of a fuel injection valve according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3.

In the figure, reference numeral 1 denotes a fuel injection valve having multiple rows of nozzles with different numbers of nozzles; row 2 has a small number of nozzles 2a arranged at equal pitches in the circumferential direction, and row 3 has more nozzles than row 2. As shown in FIG. 4, the nozzles 3a are arranged at unequal pitches q and r so that they are located between the nozzles 2a, thereby reducing the overlap of the entire spray group. In addition, each of the above-mentioned nozzles 2a, 3a
In the projection of cross section AA in FIG.
A plurality of lower nozzle axes 3 located within a pitch of 1
1 and 31 are arranged at equal pitch r, and the pitch of the axes 31 of the lower nozzles adjacent to each other across the axial center line 21 of the upper nozzle is the same as the nozzle axis 31 within the pitch of the nozzle axis 21. The pitches q between the adjacent nozzle axes 21 and the lower nozzle axes 31 are smaller than the pitch r and are equally spaced.

That is, the present invention provides a fuel injection valve having a plurality of nozzle rows 2 and 3, in which the number of upper nozzle ports 2a of the upper and lower nozzle rows 2 and 3 is smaller than the number of lower nozzle ports 3a, and Equally pitch the distance between 2a
At the same time, the lower nozzle holes 3a are arranged at two types of pitches r and q, and each of the nozzle holes 2a, 3a of the above two stages
In the cross-sectional projection of the injection valve 1, the axes 21 and 31 of the lower nozzles 3a located within the pitch X of the upper nozzle 2a are arranged at equal pitches r, and the lower nozzles 3a adjacent to the upper nozzle 2a are Pitch q
is the lower nozzle 3a within the pitch X of the upper nozzle 2a.
The pitches S between the lower and upper nozzles 3a and 2a, which are adjacent to each other via the upper nozzles 2a, are smaller than the pitch r and are arranged at equal pitches.

The operation in the case of the above configuration will be described.

Fig. 5 is a cross-sectional conceptual diagram of a combustion chamber showing the spray state of one nozzle in each of the upper and lower stages, Fig. 6 is a circumferential developed view showing the spray arrangement according to the present invention, and Fig. 7 shows a conventional example. Figure 6 is a corresponding diagram.

There are limits to the vertical position and angular offset of the nozzle arrays 2 and 3 due to the upper surface 6 of the combustion chamber and the upper surface 7 of the piston crown. For this reason, with the conventional arrangement of equal pitches, it was not possible to avoid overlapping and interference between the sprays or flames in the upper and lower rows.

In the case of the present invention, the lower jet ports 3a are arranged at unequal pitches, and the axial center line 2 of each jet port 2a, 3a is
1 and 31 are arranged so that they do not overlap in the circumferential direction, as shown in Fig. 6, the overlap of the entire spray group is reduced and the ratio of the spray to the combustion chamber is increased, thereby reducing the amount of spray or flame. The total surface area of the group increases, increasing air intake and improving combustion.

The effects of the above embodiment will be explained in more detail by comparing them with a conventional example.

The spray condition to obtain effective combustion in the combustion chamber is usually expressed as shown in Figure 5. When the lower injection angle is large, the degree of spray directly on the top surface of the piston is high, and the spray condition in the combustion chamber is The outer peripheral (lower) space cannot be used effectively, resulting in poor combustion efficiency.

Therefore, the seventh circumferential development view showing the spray arrangement
The dense state of the spray can be compared with FIG. 6 (conventional example) and FIG. 6 (present invention).

As is clear from these figures, in the conventional model (Figure 7), overlapping of sprays occurs, but in the model of the present invention shown in Figure 6, the closeness between the sprays has been improved and the sprays have been overlapped. It becomes easier for air to be taken in around the combustion chamber, and therefore, the convergence angle is also improved regarding the spread of the flame group during combustion (the solid angle extending in the combustion chamber space).

The above-mentioned ease of incorporation is explained by the following.

When the distance between the spray groups is 02 and 03 in Fig. 7, the length of the outer surface of the spray in contact with the air is expressed by the circumferential length excluding the overlapping part, and in the case of Fig. 6, since there is no overlap part, This shows that air can be taken in more easily than the conventional one shown in Fig. 7.

Furthermore, in the case of the present invention, there is no overlap between the sprays between p and r, so air is taken in from all around the spray.

As described above, in the case of the present invention, due to the unequal pitch arrangement of the nozzles in the lower row of nozzles, it is possible to minimize the overlap and interference of sprays or flames as in the conventional example, and improve engine combustion. Effective in improving performance.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the tip of a conventional fuel injector, FIG. 2 is a sectional view taken along the line A-A in FIG. 1, and FIG. 3 is a tip of a fuel injector according to an embodiment of the present invention. 4 is a sectional view taken along the line A-A in FIG. 3, FIG. 5 is a cross-sectional conceptual diagram of the combustion chamber showing the spray state of one nozzle in each of the upper and lower stages, and FIG. 6 is a cross-sectional view showing the present invention. FIG. 7 is a circumferential developed view showing the arrangement of the spray, and FIG. 7 is a corresponding view to FIG. 6 showing a conventional example. 1... Fuel injection valve, 2... Row of small number of nozzles, 3...
...Multiple nozzle rows, 2a, 3a...Upper stage, lower stage nozzles, 4,5...Spray row, 21,31...Axis of machine nozzles.

Claims (1)

[Claims] 1 It has a plurality of nozzle rows in the axial direction, and each row of nozzle rows has a plurality of nozzles in the circumferential direction, and the axis of the upper nozzle is approximately horizontal, and the axis of the nozzle on the lower stage is In a fuel injection valve configured such that the core wire is directed downward from the upper nozzle, the number of nozzles in the upper nozzle is smaller than that of the lower nozzle among the upper and lower nozzle rows, and the number of nozzles in the upper nozzle is smaller than that in the lower nozzle. The intervals between the lower nozzles are arranged at equal pitches X, and the intervals between the lower nozzles are arranged at unequal pitches q and r,
The axis of each nozzle in the two stages is such that, in the cross-sectional projection of the injection valve, the plurality of lower nozzles located within the pitch X of the upper nozzle are arranged at equal pitches R, and the two lower nozzles adjacent to the upper nozzle are The pitch q of the nozzles is arranged at a larger pitch than the lower nozzle pitch r within the pitch X of the upper nozzle, and the pitch S between the two lower nozzles and the upper nozzle that are adjacent to each other via the upper nozzle is smaller than the other pitch r. A fuel injection valve characterized by being small and arranged at equal pitches.