JPS6026158A - Direct injection type fuel injection valve - Google Patents

Abstract

PURPOSE:To prevent the deflection of the fuel spraying form and the defect on seat and improve the engine performance by installing a heat insulating means on the periphery of the injection hole of a nozzle body and preventing the accumulation of carbon deposit. CONSTITUTION:A heat-insulated air layer is formed on the periphery of an injection hole 25, and the combustion heat is transmitted into the vicinity of the injection hole 25, having the temperature markedly reduced. In this case, almost all the parts of the combustion heat received by the part close to the injection hole 25 is transmitted to the rear edge side through a nozzle body 26 and an adapter 22, the further transmitted to a cylinder head 23. Therefore, the combustion heat which is received by the part ranging from the injection hole 25 to a seat part 28 is reduced markedly, and the deterioration of the seat part 28 due to heat and the accumulation of carbon deposit in the range from the injection hole 25 to the seat part 28 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a direct injection fuel injection valve, and more particularly to a direct injection fuel injection valve that prevents deposits from forming.

(Prior art) As a conventional direct injection fuel injection valve, for example, the
There is one described in Publication No. 7-45962. This direct injection type fuel injection valve will be explained based on Fig. 1.2.
2 is a fuel injection valve, and the fuel injection valve 1 is supported by an adapter 6 on a cylinder 5 that forms a combustion chamber 4 together with a cylinder block 2 and a piston 3.

The fuel injection valve 1 includes an outward-opening Bopeso I-valve (Bopesos 1-type direct injection fuel injection valve) 7 that protrudes into the combustion chamber 1;
Electronically controlled (1, Jetronic) injector 8
1 is made from . Note that 9 is a spark plug. As shown at i' in FIGS. 2a and 2b, the bope/nod valve 7 is inserted into a nozzle body 11 in which a nozzle hole 10 is formed and the nozzle hole lO of the nozzle body 11, and its tip end cap portion 12 is inserted into the nozzle body 11 in which a nozzle hole 10 is formed. A needle valve 13 protrudes from the hole 10. The nozzle body II is screwed and fixed to the adapter 6, and the needle valve 13 is configured to be able to open and close the nozzle hole 10 from the outside. A stopper 14 and a retainer 15 are fixed to the rear end of the needle valve 13, and a spring 1G is connected between the retainer 15 and the nozzle body 11.
has been reduced.

Note that 17 is a shim.

In such a fuel injection valve l, when fuel is supplied from the electronically controlled injector 8 to the valve I valve 7, the needle valve I3 resists the biasing force of the spring 16 due to this fuel pressure, causing the needle valve I3 to move downward in FIG. 1. The engine is lifted to open the nozzle hole 10, and fuel is injected into the combustion chamber 4 in a conical shape along the shape of the tip umbrella part 12.

The fuel injected into the combustion chamber 4 is ignited by the spark plug 9, explodes and expands, and becomes high-temperature combustion gas.

However, in such a conventional direct injection fuel injection valve, the tip of the nozzle body 11 protrudes into the combustion chamber 4 and is directly exposed to high-temperature combustion gas, so the tip of the nozzle body II A large amount of high-temperature combustion gas flows into the seat portion from the injection hole 10, and these portions directly receive combustion heat. For this reason, the seat part deteriorates due to heat, and the area from the nozzle hole IO to the seat part
The fuel that reaches the top is carbonized by high-temperature combustion heat and deposited as a carbon deposit. As a result, there are problems in that the shape of the fuel spray is uneven and seat defects occur due to carbon deposits being embedded in the valve face of the needle valve 13, resulting in deterioration of engine performance.

(Purpose of the Invention) Therefore, the present invention provides a heat insulating means around the nozzle hole of a nozzle body protruding into the combustion chamber to reduce the combustion heat received near the nozzle hole. It greatly reduces the inflow of gas and prevents carbon deposits from accumulating from the nozzle hole to the seat. It also prevents deterioration due to heat in the suction part, prevents uneven fuel spray shape and seat defects, and improves engine performance. The purpose is to improve performance.

(Structure of the Invention) The direct injection type fuel injection valve according to the present invention includes a nozzle body in which a nozzle hole is formed at the tip that projects into a combustion chamber, and a tip that is supported by the nozzle body with the ability to open and close the nozzle hole. A needle valve protrudes from the seat of the nozzle hole. The above-mentioned direct injection type fuel injection valve is provided with a heat insulating means around the nozzle hole of the nozzle body to reduce the combustion heat received in the vicinity of the nozzle hole. This will significantly reduce the inflow of

(Example) Hereinafter, the present invention will be explained based on the drawings.

FIG. 3 is a diagram showing a first embodiment in which the present invention is applied to an electronically controlled direct injection fuel injection valve.

First, to explain the configuration, reference numeral 21 is an outward-opening poppet valve (direct injection type fuel injection valve), and the poppet valve 2I is connected to the cylinder navel I through an adapter (supporting member) -22.
It is attached and supported by the combustion chamber 23, and its tip protrudes into the combustion chamber 24. On the rear end side (upper side in the figure) of this poppet valve 21, an electronically controlled (L-J') injector (path shown) attached and supported by the -j' adapter 22 is installed. The injector supplies fuel at a predetermined fuel pressure to the poppet valve 2I under electronic control. The poppet valve 21 is screwed and fixed to the adapter 22 (of course, the adapter 22
The nozzle body 26 is made of metal (e.g., iron) and has a nozzle hole 25 formed at its tip that protrudes into the combustion chamber 24 as well as a nozzle body 26 that is slidably housed in the nozzle body 26. It has a needle valve 27 that can be opened and closed. The tip of a needle valve 27 is inserted into the nozzle hole 25, and the tip has a seat surface 29 that presses against the seat 28 of the nozzle hole 25 to close the nozzle hole 25, and a seat surface 29 that closes the nozzle hole 25. A widening end 30 protruding toward the combustion chamber 24 side is formed in sequence. Therefore, the needle valve 27 can close the nozzle hole 25 from the outside (from the combustion chamber 24 side). A stopper (not shown) is fixed to the rear end of the needle valve 27, and a retainer 3 [
A spring 32 is compressed via the . The splinter 32 biases the needle valve 27 in the direction in which the needle valve 27 closes the nozzle hole 25 during lightning, and the biasing force of the spring 32'' is adjusted to a predetermined value by a shim 33.

Note that 34 is Spring Sea 1-. On the side of the tip of the nozzle body 26, there is a heat insulating air layer 35 as a heat means for reducing the combustion heat received by the vicinity of the nozzle hole 25 (the part where the nozzle hole 25 and the tip water r+++ 30 are located).
A heat insulating air layer 35 is provided to surround the nozzle hole 5. This heat insulating air layer 35 is defined by closing an annular notch 36 with a triangular cross section formed on the side of the tip of the nozzle body 2G with the tip of the adapter 22.
When the Bopeso I valve 21 is attached to the adapter 22 fixed to the adapter 22, by screwing the nozzle body 26 into the adapter 22 from the combustion chamber 24 side, it is easily defined as a sealed space filled with air. It is now possible to do so. Therefore, the air layer 35 is defined by the nozzle body 26 and the adapter 22 that supports each nozzle body 26.

In addition, a notch 36 is formed in the rear body 2.
A part of the tip 6 protrudes further toward the combustion chamber 24 than the entire tip 30 of the needle valve 27, and
At the center of the tip of the nozzle body 2G protruding to the 4 side, a 4 part 37 having a conical rR angle wider than 30 is formed at the tip of the needle valve 27, 1, 1.

Next, the effect will be explained.

During engine operation, when fuel at a predetermined pressure is supplied from the injector to the poppet valve 21 at a predetermined timing, the needle valve 27 rips downward in the figure against the urging force of the spring 32 and opens the nozzle hole 25. do. As a result, fuel is injected from the nozzle hole 25 into the combustion chamber 24 from the recess 37 along the shape of the tip umbrella portion 30 . At this time, the cone apex angle of the fourth part 37 is larger than that of the first head part 30, and the fuel from the nozzle hole 25 is injected without being affected by the wall surface of the fourth part 37, resulting in good fuel spray in the combustion chamber 24. is formed.

Then, when the fuel in the combustion chamber 24 is ignited at a predetermined ignition timing and becomes a high-temperature (for example, about 2000° 0) combustion gas, the tip of the poppet valve 21 receives the combustion heat of this combustion gas. However, since the tip of the nozzle body 26 around the nozzle hole 25 protrudes b from the nozzle hole 25,
The inflow of combustion gas having a temperature of 11°Il into the vicinity of 5°C is significantly reduced. Also, there is a break around the nozzle hole 25! An air layer 35 is provided, and this hot air layer 35 has a much lower thermal conductivity than, for example, the nozzle body 26 made of metal. Therefore, the temperature of the combustion heat is significantly reduced by the chamber air layer 35, and the combustion heat is transmitted to the vicinity of the nozzle hole 25. In addition, in this case, the combustion near the nozzle hole 25 is affected! ;(Most of the water is transmitted to the rear end side of the dirt through the nozzle body 26 and adapter 22, and is further transferred to the cylinder
3. That is, the combustion heat received near the nozzle hole 25 can be released to the cylinder head 23 side. Therefore, the combustion heat received by the portion from the nozzle hole 25 to the seat I section 28 is significantly reduced compared to the conventional case, and the seat section 28
Deterioration due to heat and accumulation of carbon deposits from the nozzle hole 25 to the seat portion 28 can be prevented. As a result, it is possible to prevent defects in the sea i and deviations in the spray shape of the fuel 1'-1.

FIG. 4 is a diagram showing a second embodiment of the present invention.

In this embodiment, the tip end surface of the nozzle body 41 is
The combustion chamber 24 is arranged so that it is approximately the same as the tip surface of the il umbrella part 30.
It protrudes to the side, and the nozzle body 41 tip αj1.1
The tip of a substantially cylindrical heat insulator (heat shielding member) 42 is disposed in an annular manner around the nozzle hole 25 in the section so as to surround the nozzle hole 25 . This heat insulator 42 has a smaller f; J1 conductivity than the nozzle body 41.
For example, it is made of ceramic, etc., and the tip part protrudes beyond the nozzle body 41, and the tip part and the tip surface of the nozzle body 41 form an annular heat insulating air layer 4.
It defines 3. In addition, He 1 - Insula 42
The rear end side is interposed between the adapter 44 and the cylinder head 23, and the rear end in particular is bent outward by about 90 inches to prevent it from coming off toward the combustion chamber 24. This is the same as in the previous embodiment.

Therefore, in this embodiment, C can also achieve the same effect as in the previous embodiment, but since the nozzle hole 25 is surrounded by the insulator 42, which has a lower thermal conductivity than the nozzle body 41, Combustion heat can be reduced more than in the above embodiment.For example, if the diameter of the conventional poppet valve tip ☆11.1 is 14 mm,
If this embodiment is applied to a Bobeso valve with a similar diameter, the diameter near the nozzle hole 25 surrounded by the heat insulator 42 will be approximately 2.5 mm, and the inflow of combustion heat into the vicinity of the nozzle hole 25 will be reduced. The area can be reduced to about 1/30 compared to the conventional one. Since the vicinity of the nozzle hole 25 receives the combustion heat only by this inflow area, combustion is faster than in the above embodiment! ；Ha can be reduced by 1.

FIG. 5 is a diagram showing a third embodiment of the present invention.

In this example, heat 1. - The structure of the f insulator 48 is different from the second embodiment. The f&i/i:l side of the heat insulator 48 is interposed and fixed between the adapter 49 and the cylinder head 23, and a caulking portion 50 is formed on the f&i/i/i:l side. The heat 1/f insulator 48 is attached to the nozzle body 41 by the locking portion 5o. The rest is the same as the second embodiment.

Therefore, this embodiment has the advantage that the undulator 48 can be made smaller.

FIG. 6 is a diagram showing a fourth embodiment of the present invention.

In this embodiment, the heater 1-(insulator 54 is formed in the shape of a thin washer, and the tip part moves inward approximately 90 degrees.
It is fixedly supported at the tip of the Nosulpodi 4 by a substantially cylindrical metal collar 55 bent at 0 degrees. Further, the rear end portion of the collar 55 is bent outward approximately 90 degrees and is interposed between the adapter 58 and the cylinder head 23 so as to be held between washers 56 and 57.

Therefore, in this embodiment, the heat insulator 54
can be easily manufactured by pressing or the like, and the combustion heat received near the nozzle hole 25 can be easily released from the heat insulator 54 to the cylinder head 23 via the collar 55 and washers 56 and 57.

(Effect) According to the present invention, by providing a heat insulating means around the nozzle hole, it is possible to reduce the combustion heat received by the vicinity of the nozzle hole. It is possible to prevent carbon deposits from accumulating, and also to prevent deterioration of the seat 81 due to heat.As a result, uneven fuel jet shape and seat defects are prevented, and ζengine performance is improved. Sa-1 can be done.

In addition, in the Hs 2 embodiment described above, by defining a heat insulating air layer with a heat insulator, the combustion rate is higher than in the first embodiment! 1H can be reduced -U.

Furthermore, in the third embodiment 1911, the heat insulator can be made smaller, and in the fourth embodiment, the heat insulator can be easily manufactured.

[Brief explanation of the drawing]

Figure 1.2 shows a conventional direct injection fuel injector in a boxed view, Figure 1 is a sectional view showing its installation (=J state, Figure 2 a).
Figure 2 shows the poppet valve in a small view, Figure 2 is a view taken along arrow n-u in Figure 2a, Figure 3 is a sectional view of essential parts showing the first embodiment of the present invention, and Figure 4. 5 is a cross-sectional view showing a third embodiment of the present invention. FIG.
21-Poppet valve (direct injection fuel 1', l injection valve),
22.44.58---Adapter (support part book 1), 2
4-Combustion chamber, 25--One section, 2G, 41--Nosrubody, 27-----m;-1゛alharbu, 28--Seat portion, 35.43--One insulation air layer (1st i!: 1st means), 42.48.54---Heat insulator (heat shield part shrine). Patent Applicant Nissan Motor Co., Ltd. Representative Patent Attorney Yugagun Part Figure 1 Figure 2 (0) (b) Figure 3 2 Figure 1 Figure 5 824 Figure 6 4

Claims (3)

[Claims] (1) a nozzle body with a nozzle hole formed in its tip that protrudes into the combustion chamber; a needle valve that is supported by the nozzle body so that the nozzle can be opened and closed, and whose tip protrudes from a part of the sea 1 of the nozzle hole; 1. A direct injection fuel injection valve comprising: a direct injection fuel injection valve comprising: a heat insulating means provided around the nozzle hole of the nozzle body for reducing combustion heat received near the nozzle hole; (2) The direct injection fuel injection valve according to claim 1, wherein the heat insulating means is a heat insulating air layer defined by the nozzle body and a support member that supports the nozzle body. . (3) The thermal insulation means is arranged to surround the periphery of the nozzle hole and is defined by a heat shielding member having a lower thermal conductivity than the nozzle body, and the heat shielding portion and the nozzle body.
The direct injection type fuel injection valve according to claim 1, characterized in that the direct injection type fuel injection valve comprises four air layers.