JPS5963364A - Fuel injection nozzle - Google Patents

Abstract

PURPOSE:To both purify exhaust gas and reduce fuel consumption and noise, by controlling the maximum lift of a needle of a nozzle in order to change the injection pressure of fuel in accordance with the operational condition of an internal-combustion engine. CONSTITUTION:A control piston 2 comprises a helical control face 2a and two turn restricting plane parts 2b, and the peripheral part of the control piston 2 is slidably fitted in oil-tightness to a cylinder 3 and a control cylinder 30. An annular groove 3b is cut in the cylinder 3 being perforatively provided with a delivery hole 3c, and two plane parts 32 are provided for restricting a turn of the control piston 2. A control hole 30a is drilled in the control cylinder 30 to which a gear 24 is press fitted. A distance between the control face 2a and the control hole 30a is adjusted by relatively turning the control piston 2 and the control cylinder 30, and the maximum lift amount of a needle 1 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine concave furnace injection nozzle, and particularly to a nozzle knee 1! This invention relates to a device that can variably control the lift amount of the engine depending on the engine condition.

Hitherto, few methods have been proposed for controlling injection pressure over a wide range in accordance with the operating conditions of an internal combustion engine without significantly affecting spray characteristics. Controlling the spray characteristics means indirectly controlling combustion, and in diesel engines, especially direct injection diesel engines, whose performance changes greatly depending on the spray conditions, it is important to control the spray characteristics, that is, the fuel injection pressure. There was a request.

An object of the present invention is to arbitrarily control the maximum needle lift amount of a nozzle in accordance with the operating conditions of an internal combustion engine in order to change the fuel injection pressure.

The present invention will now be described by way of examples.

1 to 4 relate to the first embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view (B-13Itli plane view in FIG. 2), and FIG. 2 is a cross-sectional view of FIG. The cross-sectional views, FIGS. 3 and 4, each show a perspective view of the components.

Explaining the configuration of the first embodiment '4, the nostle body B
A needle 1 is provided so as to be able to reciprocate in the axial direction inside.

Reference numeral 12 denotes a holder body, which is screwed into the threaded portion of the retaining hole 11 and tightened by sandwiching the nozzle body 8 therebetween. The needle biasing spring 10 is the ml piston 20
The top of the needle 1 is urged through the connecting rod 9 in the valve closing direction of the needle 1 (in the figure) against the valve opening force of the needle 1 due to fuel pressure. working.

The piston 20 is located in the spring chamber 1 of the boulder body 12.
The spring chamber 21 is filled with fluid.The boulder body 12 has a fuel hole 12 for supplying injected fuel.
A leak hole 12b is provided to allow passage of the leakage fuel 1'-1 and the leakage fuel 1'-1. The cylinder 3 is sandwiched between a holder body 12 and a cap 4, and is tightened by ports 1 and 17.

The control piston 2 has a spiral control surface 2a and two lower surfaces 2b for regulating rotation. are slidably fitted in an oil-tight manner. Further, the cylinder 3 and the control cylinder 30 are rotatably fitted. Further, the control cylinder 30 and the protrusion 4a of the cap 4 are rotatably fitted in an oil-tight manner. Therefore, although the control piston 2 can slide vertically, its rotation is restricted. Further, the control cylinder 30 is rotatable, but
1. The downward direction is restricted by the cap 4 and the cylinder 3.

The cylinder 3 is provided with an annular groove 3b, a discharge hole 3C, and two flat surfaces 32 for regulating rotation of the control piston 2. A control hole 30a is bored in the control screw 30, and the gear 24 is press-fitted therein.

The cap 4 is provided with a suction hole 4b that communicates from the oil-tight chamber 5 to the leak hole 12b. A check valve 7 is provided to prevent leakage.

Further, a hydraulic screw 15 is fitted into the cap 4 so as to be freely slidable, and the i+l+ pressure piston 15 is urged by a spring 16 (toward the left in the figure).

Further, the hydraulic piston 15 has a rack gear 15a.
When the hydraulic piston 5 moves left and right, the control cylinder 30 is rotated via the gear 24.

The control piston 2 is biased downwardly by a spring 6 which is weaker than the needle bias spring 10.

Before explaining the operation of the first embodiment, the reason for controlling the lift m of the nozzle needle 1 will be explained.

For general throttle nozzles, piston nozzles, etc., as shown in Figure 5, the larger the knee 1' rift, the greater the effective nozzle area, which is expressed as the product of the flow rate δ1, several μ, and the nozzle cross-sectional area F. μF increases and the needle stopper position L
1 limit is determined at max.

As is well known, when the pump rotates at a low speed, the oil delivery rate from the pump to the nozzle is low, so the pressure increase is suppressed, and the nozzle injection pressure P[] becomes low. If the nozzle injection pressure is low, the spray particle size will be 4:1, which will weaken the penetration force and have a negative effect on combustion.

Maximum value of nostle needle lift amount at low speed rotation 1, ma
As shown in FIG. 5, by decreasing , the maximum value of the effective nozzle area/71imFIX also decreases. Reducing /lF corresponds to reducing the outflow l'. If the pump surface rotation speed is constant, the oil delivery rate of the pump does not change. When the fuel flowing into the pipe constricts the outlet at a constant -, the pressure inside the pipe increases by 1, so the injection pressure Po increases.

As po becomes large, part of the amount of fuel flowing into the pipe is expanded by the influence of the bulk modulus of the oil in the pipe, and the density of the fuel increases by 1, resulting in a decrease in the amount of fuel injection. Q will decrease somewhat. Pump accelerator lever that does not indicate the decrease in Q
By refilling each time, the injection period can be extended with the same injection amount. Extending the interval between injections 101 in the low speed rotation range has the effect of improving fuel efficiency and reducing noise.

Therefore, by controlling the nostle needle lift amount, combustion can be improved due to the influence of spray particle size, penetration force, and injection period.
Furthermore, improvements in engine performance such as noise reduction can be achieved.

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

High-pressure fuel is pumped by a fuel injection pump (not shown).
After passing through a jet 1/1 vibrator (not shown) and a fuel hole 12a, the nozzle needle 1 is urged upward in the figure.

When the fuel pressure PO reaches the set pressure corresponding to the seven-stroke load of the needle biasing spring 10 that is biasing downward, the needle 1, the connections 4 to 9, and the piston 20 are lifted upward and the nozzle body The fuel is emitted from the nozzle hole installed at the tip of the
4 is injected into the combustion chamber.

When the piston 20 rises by -L, the control screw 2 is hydraulically connected by the fluid filling the spring chamber 21, so that it is raised.

When the control piston 2 is lifted in one direction, the oil-tight chamber 5
The fuel filling the inside passes through the control hole 30a, the annular groove 3b, the discharge hole 3c, and the leakage hole 12b, and is returned to the pump or tank (not shown).

When the fuel pressure is not much higher than the valve opening pressure, knee 1
The lift of No. 1 is due to the upward biasing force due to fuel pressure and the knee No. 1.
It stops at the position where the downward urging force of the spring 1 (+) is balanced, but if the fuel pressure increases further and the needle 1 is lifted and the piston 20 is lifted, the control screw The I/N 2 further rises, and the control ffi'la finally reaches a position where it closes the control hole 3a, and the fluid in the oil-tight chamber 5 loses its escape route and enters a hydraulic lock state, causing the upper part of the control piston 2 to close. Movement is restricted at this point.

When the control screws I and N2 are regulated, the inside of the spring chamber 21 is also in a hydraulic lock state, and the piston 20 is also stopped, so that the lift of the knee 1' so far becomes the maximum lift.

Next, when the fuel pressure 1)o falls and the upward biasing force of the needle 1 due to the fuel pressure decreases, the connecting rod 9, the needle 1, the piston 2o, and the screws) and the hydraulic pressure The connected control screw 2 begins to drop, and the fuel corresponding to the volume increase in the oil-tight chamber 5 leaks into the leak hole 12b and the suction hole 4.
Through passage u8 of b, or leak hole 12b, discharge hole 3c
The oil is replenished into the oil-tight chamber 5 through the annular groove 3b and the control hole 30a.

As the fuel pressure PO further decreases, the nozzle needle 1 finally descends to the lowest end and closes the nozzle hole at the tip of the nozzle body 8, thereby ending the injection.

While the above injection fi culm was repeated, Ki, top 4
Left end of ＼When the supplied control hydraulic pressure P is lowered to F,
The rightward urging force on the hydraulic piston 15 due to the fluid pressure in the pressure chamber 14 decreases, and the hydraulic piston 15 moves toward the pressure chamber 1.
The rightward biasing force due to the fluid pressure in 4 and the spring 16,
1; Slide to the left until the left biasing force is balanced. At this time, the rack gear 15a controls the ``ζ control cylinder 30 via the gear 24 in a counterclockwise direction i when viewed from ``-0'' in FIG.
11 Rotate in the direction of rotation.

When the control cylinder 30 rotates and the control hole 30a moves, since the control surface 2a of the control piston 2 has a spiral shape,
The distance between the control hole 30a and the control surface 2a decreases. The control screw 1-2 has a control surface 2a with a control hole 3 (l at
-Since the stomach is restricted to the closing position, the maximum lift amount of the piston 2 of (), that is, the maximum lift amount of the needle 1, may correspond to the maximum lift amount of the control piston 2 at this time. becomes smaller than before.

From Fig. 5, when Lmax becomes smaller, the maximum effective nozzle area μPmax also becomes smaller, and due to the throttling effect, the fuel
Increase the fuel pressure PO1 and the injection pressure.

Control pressure 1) When the violet is increased, the control cylinder 30 rotates in the R1 rotation direction when viewed from above in FIG.
The phase difference between a and the control surface 2a is 1! Since III becomes larger, the maximum lift of the needle l becomes larger, and the maximum effective nozzle area μ! 'max will also be large.

The advantages of this hydraulic linkage are explained below.

The amount of general Ni-needle rift is minute, and it is difficult to precisely control that minute amount with good accumulation, but the piston 2
By making the cross-sectional area of the control screw 1-2 smaller than the cross-sectional area of the control screw 1-2, the amount of lift of the control screw 1-2 can be amplified. In other words, since the bulk modulus of the fluid in the spring chamber 21 is smaller than the volume change number J-, (cross-sectional area of the piston 200J) x (amount of movement of the histone 20) - (
The cross-sectional area of the control screw 1 and 2) x (the amount of movement of the control screw 1 and 2). Therefore, the amount of movement J of the screw I/N 20 is amplified to the amount of movement of the control piston 2, and the amount of movement J of the control screw I/N 2 is amplified.
By finely controlling the piston 20, the piston 20 can be controlled with a good degree of integration, and as a result, the needle 1 can be controlled with a degree of <4.

Furthermore, the advantage of performing rotational control is that sliding resistance can be reduced, and as a result, control force can be reduced.

A second embodiment of the invention is shown in FIG.

In Figure 6, h (a+ is a longitudinal cross-sectional view (l3-1 in Figure (b))
31 analysis surface view), (bl is (a+ figure 8-in sectional view, t
c+ and (dl) respectively indicate the top view of the component.

Focusing on the differences from the first embodiment, the second embodiment also changes the relative distance between the control hole 30a and the control surface 2a by rotation, but unlike the first embodiment, The control hole 30a of the control cylinder 30 is fixed and is used to control rotation of the control surface 2a.

In the first embodiment and the second embodiment 1911, the piston 20 and the control piston 2 have a hydraulic connection structure.
The control piston 2 may be mechanically connected to the needle 1 by eliminating the screw 20 and providing a spring receiver 20' in its place, as in the third embodiment shown by a+ to (dl).

In addition, the control surface 2a is shown in FIG. 8 (
A wall with a spiral shape as shown in Fig. 8 (b) may be simply sloped as shown in Fig. You can also do this.

1 i1'? As explained above, the present invention has a needle 1 in the central axis direction of the nozzle body 8 having the fuel injection hole 8a.
is slid back and forth to open and close the fuel i-1 injection hole 8a.
A fuel injection nozzle that performs fuel injection includes a needle biasing spring IO that biases the needle I in a direction in which the fuel injection hole 8a closes, and a control screw 1 having a control surface 2a.
an oil-tight chamber 5 adjacent to the control surface 2a, a control cylinder 30 having a control hole 30a open to the oil-tight chamber 5, and a check brake r7 that only allows flow into the oil-tight chamber. , the Mil control piston 2 and 11-control cylinder 30 are relatively rotated, and the control surfaces 2a and jl++I are rotated relative to each other.
In adjusting the distance lTl11 between the hole 30a, 1
; Since the maximum lift amount of the needle 1 is controlled, it can be controlled with a small control force and the needle l! The maximum lift amount of Le 1 is an internal combustion engine +! I! It is possible to control the operating condition of I (to '1; centering to C fine 3111), resulting in effects such as -11 in fuel efficiency, purification of exhaust gas, and low noise and acidity.

[Brief explanation of the drawing]

FIGS. 1 to 4 relate to the first embodiment of the present invention, and FIG.
Figure 2 (, is a Δ-Δ cross-sectional view of Figure 1, Figures 3 and 4)
The diagram shows the component parts. J2 diagrams are shown respectively -ζ. FIG. 5 is a characteristic diagram of a general suronotornozzle, a bintle nozzle, etc. Figures 6(a) to (C1) relate to the second embodiment of the present invention, and +al is a cross-sectional view (13-1 in Figure 6(b)).
3 sectional view), (t+) is (Δ-Δ sectional view of figure 8+, (0
) and (((1) perspective views of the old J component parts are shown respectively. FIGS. B-B of bl Fl
II side view), (bl is 8-fold sectional view of fa1 view, (C
) and (dl each indicate a perspective view of the component parts.
Front view and 1f of each modification of an side 2a
ill 1lii Figure 1 shows each. ■...knee IJ le, 2...control piston, 2a...
・Mtll 111 side, 5...Oil-tight chamber, 7...Return brake r, 8...Nosle book, 8a...fuel (', [injection hole, 10...knee 1' throat Biasing sub 1 long, 30
...control cylinder, 30a...ili'l fal
Finished. Agent Bu ``Buried soil Takashi Okabe Figure 1 Figure 2 Figure 3 Figure 6 (b) Figure 7 (4) Figure 7 (b) Figure 8

Claims (1)

[Claims] In the fuel injection nozzle, which performs fuel injection by opening and closing the fuel injection hole by reciprocating the needle in the direction of the central axis of the nozzle body having the fuel injection hole, the needle described in nij. a needle biasing spring that biases the fuel injection hole in a direction to close, a control piston having a control surface, an oil-tight chamber adjacent to the control surface, and a control cylinder having a control hole that opens into the nuclear oil-tight chamber; A check valve is provided to prevent only the inflow of the oil-tight chamber, and the control piston and control cylinder are relatively rotated and the distance between the control surface and the control hole is adjusted. A fuel injection nozzle characterized in that a maximum lift m of the needle j' is controlled.