JPS5963363A - Fuel injection nozzle - Google Patents

Abstract

PURPOSE:To enable the injection of fuel to be accurately controlled throughout a wide range of operational condition, by controlling the maximum needle lift of a nozzle in order to change injection pressure in accordance with the operational condition of an internal-combustion engine. CONSTITUTION:A needle urging spring 10 is adapted to the first piston 20 to urge the top part of a needle 1 through a connecting rod 9 in the closing direction of the needle 1 against the urging force of opening the needle 1 by the pressure of fuel. The first piston 20 is oil-tightly and slidably fitted to the wall of a spring chamber 12c filled with fluid in a holder body 12. The second piston 2 having a helical control face 2a is slidably and turnably fitted in oil-tightness to two cylinder walls 3c, 3d of a cylinder 3. A control hole 3a communicated to an oil tight chamber 5 is drilled in the cylinder 3. The second piston 2, whose lift is restricted at a position where the control face 2a closes the control hole 3a, decreases a lift amount of the first piston 20 corresponding to the maximum lift amount of the second piston 2 at said position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a fuel injection 1.1 nozzle for an internal combustion engine, and it has a direct effect on the combustion of the internal combustion engine. It is something that

Hitherto, few methods have been proposed for controlling the injection pressure over a wide range according to the operating state of the internal combustion engine without significantly affecting the injection T'A characteristics. Controlling the injection properties involves indirectly controlling combustion, so in diesel engines, especially direct injection diesel engines, where the performance changes greatly depending on the spray condition, There was a strong demand for control of spray characteristics, that is, injection pressure.

In response to the above-mentioned request, the present invention has been developed to increase the nozzle's maximum needle lift of 1M in order to change the injection pressure when operating an internal combustion engine. 1
The purpose of this is to reduce the resistance associated with control operation, which is a problem when performing arbitrary control according to the conditions, and to expand the control operation range.

The T-tree invention will now be described based on examples.

1 to 4 are concave portions of the first embodiment of the present invention, and FIG. 1 is a cross-sectional view (B-B IIJi plane view in FIG. A sectional view, FIGS. 3 and 4 each show a perspective view of the component parts.

To explain the structure of the first embodiment, a needle 1 is provided in the nozzle main body 8 in the direction of the ζ axis so that the needle 1 can be reciprocated.
It is screwed into the threaded part of II and tightened by sandwiching the nozzle body 8. The knee 1 biasing spring 10 is the first
The knee 1 is in contact with the knee 2o through the connecting rod 9.
``Place the top of ``le 1'' on the lunar pressure knee 1'' with the opening of ``ru.
Resisting the biasing force, the needle 1' exerts a force in the direction of closing the valve.

1st screw 1n 20, 1; 1; Ruder; 1! day 12
The sublink chamber 12c is slidably fitted in an oil-tight manner to the wall of the sublink chamber 12c filled with fluid. Boulder body 12 has
A smoking material hole 12a for supplying the injection 11ks 11 and a simple leak hole 12a for allowing leakage fuel to pass through are bored.

Cylinder 3 is sandwiched between Boulder Pode 12 and Ki, Top 4, and Pol 117! -There are some people who are tightened up.

The second piston 2 has a helical control surface 2a, which is oil-tightly connected to the two cylinder walls 3c, 3d of the cylinder 3.
The lowermost position 114 is regulated by a stopper 22 fitted in a groove in the cylinder wall 3c, which is rotatably fitted during one movement. In addition, there is a parallel flat n1- with 12 sides on the upper part of the second piston 2, into which a gear 24 is press-fitted, a chisel gear 21; However, the rotation is a mutually defined mechanism.

A control hole 3a communicating with the oil-tight chamber 5 is bored in the cylinder 3, and the annular groove 12c provided in the boulder 12 is connected to the leak hole 12b.

) In addition, the cylinder 3 has a check valve 7 in a part of its path.
A suction hole 3b is bored, and inside this suction hole 3b, the fluid flows in the direction of flowing into the oil-tight chamber 5. Also, this suction hole 313 is different from the oil-tight chamber 5 side.・
The end communicates with the leak hole 121 via the annular groove 12c.

- A hydraulic screw 15 is slidably fitted into the top 4 in an oil-tight manner, and the hydraulic screw 15 is urged leftward in the figure by a spring 16.

Further, the hydraulic piston 15 has a rack gear 15a,
When the hydraulic screw 15 moves left and right, the gear holder 23 rotatably fitted to the protrusion 4a of the gear 4 via the gear 24 rotates, and the m2 screw 12 rotates.

"2 & 1J '4;j of the second piston 2a: % prenoci? through the frame 125 to the -C spring 6;
The needle is urged toward the needle with an extremely weak force compared to the needle urging spring 10.

Before explaining the operation of the first embodiment, the reason for controlling the amount of reflux of the C nostle needle 1 will be described.

The general sootl nozzle and screw 1 nozzle cap are shown in Figure 5. If the lift amount 1 is increased, the effective nozzle area μF, which is expressed as the product of the number p of the flow instep i11 and the cross-sectional area F of the nozzle, increases, and the upper limit is determined by the stopper position Lmax of the knee I'.

As is well known, the pump is 11 (when rotating at high speed, the feed from the pump to the nozzle i1 + ¥ - is low, so the increase is suppressed, and the nozzle jet 1 1 pressure 1) 0 is (I ( If the nozzle spray angle 1 pressure is 11 (11), the spray particle size will become large and the shell 1 force will be weakened, which will have a negative effect on combustion.
figure. Low speed rotation 11! By decreasing the maximum value Lmax of the nostle needle lift I-amount to f, the maximum value of the effective nozzle area 1IFIIlax can be obtained from the dog 5 figure.
also becomes smaller.

Reducing μF corresponds to reducing the outflow 11. If the pump rotation speed is constant, the oil delivery rate of the pump does not change. Since the fuel 1 that flows into the pipe flows out at a constant rate and reduces the amount of fuel 1, the pressure inside the pipe increases, so the injection pressure J'o increases.

In order for po to become a person, rli! Ura's 1 yen load in the jurisdiction 1) 1
Due to the influence of the fuel efficiency, a part of the amount of fuel flowing into the pipe is taken by the 11.15 tension of the pipe and the density of the fuel f1, which causes the injection IQ to be slightly less by 1'eK. By replenishing the decrease in Q using an accelerator bar (not shown) of the pump, the injection period can be extended with the same injection amount.

Extending the injection period in the low speed one-way transition region improves fuel efficiency and reduces noise (It).
In order to control the lift amount, 1-li, spray particle size,
Improved combustion due to the influence of penetration power and injection period! It will be possible to achieve improvements in engine performance such as field noise reduction.

Next, the operation of the first embodiment will be explained with reference to FIGS. 1 to 4.

Fuel t1 injection (not shown), 1! The high-pressure fuel 1'1 that is pressure-fed from the tube passes through an injection pipe and an eve (not shown in the figure), and becomes a fuel! 1
After passing through the holes 12, +, the nozzle needle 1 is placed in the chair 4- on the upper blade in the figure.

Needle (=
When the pressure reaches seven strokes corresponding to the load of the spring 10, the knee 1, the connecting frame 9, and the first piston 20
1. The fuel 1'1 is injected into the combustion chamber from a nozzle hole provided at the tip of the nozzle body 8. When the first screw 1-2 () collapses, the spring chamber 21 is filled with fluid 4J, which causes the second screw 1-2 (2), which is hydraulically connected to the first screw 1-20, to rise. Ru. When the second screw 1 (2) is lifted to one side, the material filling the oil-tight chamber 5 passes through the control hole 3a, the annular groove 12 (7), and the leakage hole L2b, and passes through the pump or tank (not shown). When the fuel pressure is not much larger than the valve opening pressure, the lift pressure of needle 1 will be increased by 1.
The engine stops at the position where the J9 force and the downward biasing force of the knee 1'le ('-J force spring 10) are balanced, but the fuel pressure further increases by -L and the knee 1'le l becomes 1↓. When the first screw 1 is raised and the first screw 20 is raised, the second piston 2 becomes even more difficult, and the control surface 2a is finally stopped.
The fluid in the oil-tight chamber 5 loses its escape route and becomes hydraulically closed, and the upward movement of the second screw 1 and 2 is restricted at this point, and the fluid in the spring chamber 21 also closes. Also, the oil pressure becomes 11 and the 1st screw 1st screw 2nd
0 stops, knee 1 so far! The lift amount of Le 1 becomes the maximum rif 1 amount.

Next, the fuel 1'+1 pressure Po decreases F, and the upward biasing force of the needle l due to the fuel 1 pressure becomes 41-T'.
, the needle 1 together with the first screw 1 20 and the first piston and the hydraulic pressure 3! l! The dry second screw 12 continues to fall, and the increased volume inside the oil-tight chamber 5 causes the leakage hole 12b, the annular groove 12C1, the reverse IL valve 7, and the suction hole 3b. 'C1 or the leak hole 12b, the annular groove 12C2 and the control hole 3a, the oil field chamber 5.\1 is charged.

As the fuel 111E Po further decreases, the nozzle needle 1 finally descends to the lowest position Oi:^, and the injection hole at the tip of the nozzle body 8 is closed, thereby ending the injection n1.
Ru.

While the above injection stroke is repeated, if the control oil pressure supplied to the left end of the kit knob 4 is increased -υ, the fluid pressure in the pressure chamber 14 causes the screw 1 15 to move in the right direction. As the force increases, the hydraulic screw 15 is biased to the right by the fluid pressure in the pressure chamber 14 and to the left by the spring 16.
ff1L Balance of force・) Slide to the right. At this time, the rasokugi 1'' 15a is inserted into the second piston 2 through the gear 24 and gear 23 at a time of 81 when viewed from above.
Rotate in the direction of rotation.

When the second piston 2 rotates J, the relative distance t[] between the control hole 3a and the control surface 2a decreases because the control surface 2a has a cape-shaped spiral shape.

The second screw 1-2 at this time is regulated because the 'C litho 1 is restricted to the position where the control surface 2a closes the control hole 3a.
The maximum lift amount of the first piston 20 corresponding to the maximum lift amount of the needle l, that is, the maximum lift l-m l, 1101
× becomes smaller than before j. From FIG. 5, when Lmax becomes smaller, the effective nostle area 1t Fmax also becomes smaller, and the aperture 9. If fuel for 1''1 population is burned in IJ fruit
P o, that is, the injection pressure increases.

When the control pressure P1 is reduced, the valve ring 3 rises, and the maximum lift of the needle 1'Iil l1. ma is a person, and the maximum effective nozzle area μPmax is also a person.

The advantages of this hydraulic coupling mechanism are the following points 1) and 2).

■), generally knee 1' riff l ■ + J: ii', ? The minute amount is controlled in this way with precision.It costs ¥11, but the first piston 20
By making the cross-sectional area of the second piston 2 smaller than the cross-sectional area of the second piston 2, the amount of lift of the second piston 2 can be amplified.

In other words, since the volumetric change in the bulk modulus of the fluid in the spring chamber 21 is minute, (cross-sectional area of the first screw 20) x (movement W of the first screw 20) - (second Screw 1
It is assumed that the cross section of the pin 2 is f1'()X (the amount of movement of the second screw 1 and the pin 2). υ (means the amount of movement of the first screw
By amplifying the moving element 11 of the screw 1 and controlling the second screw 1 2 in a fine area, the first piston 20 can be controlled finely and accurately.

2) The ml piston 20 and the second piston 2 as shown in FIG. ++ U 20 allows the rotational resistance of Bevis 1 and 2 to be extremely small compared to those of the ζ-color structure which are mechanically connected. In other words, in Figure 6, Ura V+i
Room 5 is ill 1. E l: + When the tsuku-like combination is used, the lower mash of the 2nd biscuit 1 and 2, I! When a large load is applied, the rotational resistance becomes extremely large due to the frictional resistance of that surface.The 1-n hydraulic connection structure C in Figure 1 avoids this situation. I can do it.

In the first embodiment, the rotation of the second piston 2 having the control surface 2a was controlled by fixing the c:1 control hole 3aζJ, but the rotation was t, r
Control cylinder 3 that is L-controlled and has 11+ control holes 3a
The present invention that controls the rotation of 0! 'l'l 2 examples 7th
As shown in the figure.

In Fig. 7, (nl +; l numbered at the lower end of the second screw 1, t, parallel opposing surfaces 21 for controlling the rotation)
is installed on the protrusion at the end of the cylinder 3F, and its rotation is restricted.

8th, instead of controlling the rotation, the hydraulic pressure 1) is controlled by 11 to balance it with the spring force of the spring 6".
A third embodiment of the present invention is shown in which L3a is controlled by sliding.

In short, any mechanism may be used as long as it can change the relative distance ff1lj between the control hole 3a and the control surface 2a.

In addition, in the first and second embodiments, the rack gear was moved/rotated by hydraulic pressure, but the gear may also be rotated/rotated by, for example, a DC or a step motor. .

In short, any device that can control the rotation of the second screw I/N 2 or the control cylinder 30 may be used.

Furthermore, in the vertical structure of the third embodiment shown in Fig. 8, an L-bar 41 is used in the main part It (1.. in the cross-sectional view) of the ill 4 embodiment shown in Fig. 9 to control the °C sleeve. It's okay.

In addition, the control surface 2a of the first embodiment (Tari, second embodiment) is 11
There is a spiral shape 1:,'C in figure 0 (shown in BL),
#:n of ta+ in FIG.
, (°ζ may also be axially symmetrical like dl.

As described in detail below, the present invention is directed to the direction in which the LED tl injection n1 821 closes (=J
Knee 1' Louis = 1 force spring 10 and knee 1'
a first screw 1 20 mechanically connected to the first screw 1 and 11; a second piston 2 hydraulically connected to the first screw 1 and having a control surface 2a; and a second piston 2 adjacent to the control surface 2a. An oil-tight chamber 5, a control hole 3a opening 11 into the oil-tight chamber 5, and a check valve 7 that prevents only the inflow into the oil-tight chamber 5, and a control surface 2a and a control hole 3a. By adjusting the relative distance Fill between the needles, the maximum lift amount of the needle 1 is controlled.The force required for control can be reduced and the operating conditions can be widened. It is effective to be able to precisely control 1ri over 1 range.

[Brief explanation of the drawing]

Fig. 1 to Fig. 4 1J The first embodiment of the present invention has a concave section 11 (-1 cross section 1 (13-B section 1 in Fig. 2)
Tsu I), ff! 2 drawing number, ■ Δ-8 side view of Fig. 1, No. 3
Figure 4 shows the first view IU+ of the component parts. It is a cross-sectional view of the fuel injection nozzle used for the second embodiment of the present invention.
13L3 sectional view of the figure), fll) +; ls 3 Example 1 ((cross section,
FIG. 9 is a sectional view of the main part of the fourth embodiment of the present invention, FIG.
11 to (C1) are control surfaces 2 of the second piston 2 of the present invention
Fig. 3 shows a front view and a side view of various modifications of Fig. a. ■...Needle, 20...1st screw 1, 2...
2nd screw 1, 2a... control surface, 3a... control hole,
5... Oil tight chamber, 7... Reverse 1L valve, 8... Nozzle body, 8a... Fuel oil 1 injection hole, 10... Needle biasing spring, 12a... Fuel oil 1 1 hole, 12b...
Leak hole, 21...spring chamber. Agent Burido Okabe No. 1 [' + 1-2 Figures 3''i 4 I, 1 and j 5 [
4 Needle lift-t L No. 6E4 Mountain 7 Fig. (2L) Fig. 7 (C) No. 8121

Claims (1)

[Claims] Knee 1' in the direction of the central axis of the nozzle body having the fuel injection hole
Move the needle back and forth to open and close the fuel injection hole to perform fuel injection.In the ＼ size injection nozzle, move the needle in the direction that closes the fuel injection hole. Biasing knee 1
(= J force spring, m1 screw 1 which is mechanically connected to the needle, and oil on the ffl 1 screw 1)
A second screw 1 is connected in an F manner and has a control surface, and an F/! ? an oil-tight chamber in contact with the oil-tight chamber, a control hole opening into the oil-tight chamber, and a check valve for allowing the inflow of the oil-tight chamber; Relative distance Pi1
1. A fuel 1''1 injection nozzle, characterized in that the maximum reflux amount of the needle 1' is controlled by adjusting the needle 1'.