JPH08144882A - Distributed fuel injection pump - Google Patents

Abstract

(57) [Summary] [Purpose] Good inhalation of fuel. The intake port 9 is bent at a position eccentric to the rotation center line C of the rotor and extends from the outer peripheral surface 4a of the rotor facing the circumferential groove fuel supply port 6a to the bent portion 23.
4 and the discharge hole 2 extending from the bent portion 23 to the fuel suction passage 8
5 and. Fuel supply port 6 at outer peripheral surface 4a of rotor
The open mouth portion 26 of the introduction hole 24 communicating with a is the open mouth portion 26.
Is opened toward the rotational direction side of the rotor along the tangent T that contacts the outer peripheral surface 4a. A centrifugal force associated with the rotation of the rotor exerts a force on the intake fuel of the intake port 9 to separate it from the rotation center line C in the radial direction. However, since the intake port 9 has a bent portion 23, the inner surface of the bent portion 23 particularly has centrifugal force. The centrifugal force acts on the intake fuel. When the opening port 26 collides with the fuel of the fuel supply port 6a as the rotor rotates, the fuel of the fuel supply port 6a is easily sucked into the opening port 26 by the reaction force of the rotational force to the component force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed fuel injection pump for distributing and pressure-feeding fuel to each cylinder of a multi-cylinder engine by reciprocating motion and rotary motion of a single plunger, and more particularly to improvement of its fuel intake port. Is.

[0002]

2. Description of the Related Art In a conventional inner-cam type distribution type fuel injection pump disclosed in Japanese Utility Model Laid-Open No. 63-34357, when a rotor rotates on a rotation center line in a rotor housing, one of intake ports in the rotor is opened. One communicates with the fuel intake hole in the rotor housing, and the fuel from the fuel intake hole reaches the center passage in the rotor through the intake port. The fuel in the center passage is one of the fuel discharge passages in the rotor housing. It communicates with two components and is distributed and pressure-fed from the discharge passage to the fuel injection nozzle of one cylinder.

Each intake port in the rotor is linearly extended from the center passage in the radial direction of the rotor and is opened in the circular outer peripheral surface of the rotor. Incidentally, JP-A-5-1260
Also in the conventional inner-cam type distribution type fuel injection pump shown in JP-A-2008, each intake port of the rotor is extended in a shape similar to that described above.

[0004]

However, since each intake port is linearly extended in the radial direction from the center line of rotation of the rotor as described above, the fuel in each intake port is generated during rotation of the rotor. It receives a centrifugal force that is in the opposite direction to the fuel suction force in the radial direction toward the rotation center line of the rotor. Therefore, the suction of the fuel is hindered by the centrifugal force. In particular, at high speed rotation, the fuel suction time is shortened and the centrifugal force is increased, so that it is difficult to suck the fuel, and it is difficult to obtain a sufficient injection pressure and injection amount.

An object of the present invention is to improve a fuel intake port in a distributed fuel injection pump to improve fuel intake.

[0006]

In the distributed fuel injection pump according to the first aspect of the invention, the fuel from the fuel intake passage provided on the rotation center line in the rotor rotating in the cylinder is pressurized in the rotor. The fuel is pressurized by the rotor, and this pressurized fuel is distributed under pressure from the discharge port of the rotor to each fuel distribution passage in the cylinder as the rotor rotates. An intake port is provided in the rotor between a fuel supply port provided on the inner peripheral surface of the cylinder and a fuel intake passage of the rotor. The intake port is bent at a position eccentric with respect to the rotation center line of the rotor, and has an introduction portion extending from the outer peripheral surface of the rotor facing the fuel supply port to the bent portion, and an exhaust portion extending from the bent portion to the fuel intake passage. Is equipped with.

In the second invention, the fuel supply port of the first invention is a peripheral groove facing the entire outer peripheral surface of the rotor, and the opening of the introduction portion of the intake port communicating with this fuel supply port on the outer peripheral surface of the rotor. The portion is opened toward the rotation direction side of the rotor along the tangent line that contacts the outer peripheral surface of the rotor at this opening.

[0008]

The fuel flows from the peripheral groove fuel supply port into the open port of the intake port, and reaches the fuel intake passage through the inlet and outlet of the intake port. In that case, the centrifugal force generated by the rotation of the rotor acts on the intake fuel in the intake port and the fuel intake passage in a radial direction from the center line of rotation of the rotor. However, since the suction port has a bent portion, the inner surface of the suction port, especially the inner surface of the bent portion becomes a resistance against centrifugal force,
Only the centrifugal component acts on the intake fuel. Further, when the open port collides with the fuel in the circumferential groove fuel supply port as the rotor rotates, the fuel in the circumferential groove fuel supply port is easily sucked into the open port by the reaction force against the component force of the rotational force. Become.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An inner cam type distribution type fuel injection pump according to a first embodiment of the present invention will be described below with reference to FIGS.

First, an inner cam type distribution type fuel injection pump schematically shown in FIG. 1 will be outlined. A cylinder 2 is mounted in the housing 1. The rotor 3 in the housing 1 comprises a rod 4 and a head 5. The rod 4 is rotatably inserted into the cylinder 2 so that the circular outer peripheral surface 4a of the rod 4 slides on the circular inner peripheral surface 2a of the cylinder 2. Touching.
A plurality of feed galleries 6 (fuel low-pressure chambers) are arranged in the cylinder 2 on the outer circumference of the rotor 3 at equal intervals in the circumferential direction. Each feed gallery 6 is provided on the inner peripheral surface 2a of the cylinder 2.
The peripheral groove-shaped fuel supply port 6a is formed so as to face the outer peripheral surface 4a of the rod 4. A fuel supply passage 7 that communicates with one feed gallery 6 is formed in the cylinder 2.

A fuel intake passage 8 is formed in the rotor 3 on the rotation center line C, and the fuel intake passage 8 is formed.
An intake port 9 is formed between the fuel supply port 6a and the circumferential groove fuel supply port 6a of the feed gallery 6. This fuel intake passage 8 is an electromagnetic switching type spill valve 10 (relief valve) in the rod 4.
Is communicated with the valve chamber 11. In the spill valve 10, a valve body 12 is fitted in the rod 4 so as to be movable along the rotation center line C on the rotation center line C. A valve seat 13 is formed at the boundary between the fuel intake passage 8 and the valve chamber 11, and the valve body 12 moves to come into contact with or separate from the valve seat 13. The movement of the valve body 12 is performed by demagnetizing the solenoid 14.

A pair of pressurizing plungers 15 are inserted into the head 5 of the rotor 3 and a pressurizing chamber 16 is formed between their inner ends. Both pressurizing plungers 15 reciprocate in the radial direction orthogonal to the rotation center line C of the rotor 3.
An inner cam 17 is attached to the inside of the housing 1 on the outer periphery of the head 5 of the rotor 3, and the outer ends of both the pressure plungers 15 are in sliding contact with the inner cam 17.

A fuel discharge passage 18 is formed in the valve chamber 11 of the rod 4 of the rotor 3 so as to communicate with the fuel suction passage 8 via a valve seat 13. In the rotor 3, a pressurizing passage 19 is formed from the pressurizing chamber 16 of the head 5 to the rod 4, and the pressurizing passage 19 and the fuel discharge passage 18 meet at the discharge port 20 on the outer peripheral surface 4 a of the rod 4. There is.

On the outer circumference of the rod 4, a plurality of fuel distribution passages 21 are arranged in the cylinder 2 at equal intervals in the circumferential direction. Each fuel distribution passage 21 communicates with the discharge port 20 of the rotor 3 on the inner peripheral surface 2a of the cylinder 2 as the rotor 3 rotates. A plurality of delivery valves 22 that are one-way passage valves are provided outside the housing 1, and each delivery valve 22 is connected to each fuel distribution passage 21. Each delivery valve 22 is connected to each injection nozzle (not shown) of the diesel engine.

In this embodiment, the shape of the suction port 9 is improved. As shown in FIG. 2, this intake port 9
Is bent at a position eccentric with respect to the rotation center line C of the rotor 3, and the circumferential groove fuel supply port 6a of the feed gallery 6 is bent.
Introduction hole 24 (introduction portion) extending from the end to the bent portion 23
And a discharge hole 25 (discharge portion) extending from the bent portion 23 to the fuel suction passage 8. Into the introduction hole 24, the outer peripheral surface 4a of the rod 4 of the rotor 3 is provided with the circumferential groove fuel supply port 6a.
Is formed with an open mouth portion 26 communicating with.

The outer peripheral surface 4a of the rod 4 is formed by the opening 26.
Assuming a tangent line T that is in contact with, the opening port portion 26 is opened toward the rotation direction side of the rotor 3 along the tangent line T. That is, when the extension center line 24a of the introduction hole 24 is assumed to be an extension line extending to the circumferential groove fuel supply port 6a side through the opening port 26, this extension line extends from the normal line to the tangent line T to the rotation direction side. It is inclined. Extension center line 2 of the introduction hole 24
4a extends straight to the bent portion 23, and the extension center line 25a of the discharge hole 25 is bent from the extension center line 24a to the rotation center line C side at this bend portion 23 and extends straight to the rotation center line C. ing.

The fuel passes from the fuel supply passage 7 through the feed gallery 6 to the circumferential groove fuel supply port 6a, and the rotor 3
With the rotation, the fuel is introduced into the fuel intake passage 8 from the circumferential groove fuel supply port 6a through the intake port 9. When the valve body 12 of the spill valve 10 is opened apart from the valve seat 13, the fuel flows from the fuel intake passage 8 through the valve chamber 11 to the fuel discharge passage 18, and reaches the discharge port 20, the pressurizing passage 19 and the pressurizing chamber 16. Also flows in. When the valve body 12 of the spill valve 10 abuts on the valve seat 13 and closes, and both pressurizing plungers 15 approach each other to pressurize the fuel in the pressurizing chamber 16, the pressurizing chamber 1
The fuel in the pressure passage 19, the discharge port 20, and the fuel discharge passage 18 communicating with the fuel cell 6 is also pressurized.

When the discharge port 20 communicates with one of the fuel distribution passages 21 as the rotor 3 rotates, the pressurized fuel is delivered from the fuel distribution passage 21 to the delivery valve 22.
And is distributed under pressure to a fuel injection nozzle (not shown).

After that, when the valve body 12 of the spill valve 10 is opened again as the rotor 3 rotates, the pressurized fuel is released.
1 and the fuel suction passage 8 and the suction port 9 to flow back to the feed gallery 6.

In this way, the fuel suction and distribution pressure feeding are repeated, and the pressurized fuel is sequentially distributed pressure feeding to each fuel injection nozzle. In this case, when the opening / closing timing of the spill valve 10 is adjusted, the fuel reverse flow timing is changed and the fuel injection amount is controlled.

This embodiment has the following characteristics (a) to (d). (B) As described above, the fuel flows from the circumferential groove fuel supply port 6 a of the feed gallery 6 to the opening port 26 of the intake port 9.
To the fuel intake passage 8 through the inlet hole 24 and the outlet hole 25 of the intake port 9. In that case, the centrifugal force associated with the rotation of the rotor 3 acts on the intake fuel in the intake port 9 and the fuel intake passage 8 in a radial direction from the rotation center line C of the rotor 3. However, since the suction port 9 has the bent portion 23, the inner surface of the suction port 9, in particular, the bent portion 23 and the inner surface of the introduction hole 24 becomes a resistance against the centrifugal force, and only the component of this centrifugal force acts on the intake fuel. Therefore, it is possible to satisfactorily inhale the fuel.

(B) As described above, since the opening port portion 26 of the intake port 9 is opened toward the rotational direction side of the rotor 3, the opening port portion 26 is rotated along with the rotation of the rotor 3 so that the circumferential groove fuel is formed. When the fuel collides with the fuel in the supply port 6a, the fuel in the circumferential groove fuel supply port 6a is easily sucked into the opening 26 due to the reaction force of the rotational force to the component force. Therefore, it is possible to satisfactorily inhale the fuel.

(C) As described above, the spill valve 1
By controlling the fuel injection amount to 0, it is possible to satisfactorily inhale the fuel. (D) The above-described fuel intake is performed with a small pressure difference and is easily affected by the centrifugal dynamic pressure, so that the bent portion 23 has a large effect. On the other hand, the reverse flow of fuel (spill)
In regards to (2), since it is carried out with a large pressure difference and there is almost no influence of the centrifugal dynamic pressure, it is possible to obtain the spill performance equivalent to that of the conventional case.

Next, another embodiment of the present invention will be described focusing on the difference from the first embodiment. In the intake port 9 of the second embodiment shown in FIG. 3, the shape drawn by the extension center line 24a of the introduction hole 24 and the extension center line 25a of the discharge hole 25 which are continuous via the bent portion 23 is a spiral line. Has become. Here, the spiral line is a generic term for a continuous line that rotates around a certain point or axis while moving away from it. That is, both extension center lines 2
A continuous line composed of 4a and 25a is a rotation center line C of the rotor 3.
Rotating away from. When the suction port 9 is formed in a spiral shape in this manner, the introduction hole 24 of the suction port 9 is formed.
Since the passage resistance is smaller than that in the first embodiment in which the discharge holes 25 are formed linearly, the suction efficiency is excellent. However, the first embodiment is superior in terms of workability.

In the third embodiment shown in FIG. 4, one suction port 9 of the first embodiment is added, and two suction ports 9 and one pressurizing passage 19 are circumferentially spaced by 120 degrees. It is installed in. Therefore, the fuel can be sucked in better.

In addition to the above embodiments, the following configuration may be adopted. (A) Although each of the above-described embodiments is embodied in a distribution type fuel injection pump having a specific structure including the spill valve 10, another type of distribution fuel injection in which such a spill valve 10 is not provided in the rotor 3 is used. Pump (for example, actual development 6
The technical idea of the present invention is applied to those disclosed in JP-A-3-34357 and JP-A-5-126008).

The technical ideas (other than the claims) which can be understood from each of the embodiments will be described together with the effects. (A) In the rotor 3 according to claim 1 or 2, a spill valve 10 that opens and closes between a fuel suction passage 8 communicating with the suction port 9 and a fuel discharge passage 18 communicating with the discharge port 20 is provided. Set up. Therefore, the fuel injection amount can be controlled as described above.

[0028]

According to the distributed fuel injection pump of the present invention, the suction port is bent to improve the extended shape and the orientation of the opening portion, so that the fuel can be satisfactorily sucked. .

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an inner cam type distribution type fuel injection pump according to a first embodiment.

FIG. 2 is an enlarged sectional view taken along line XX of FIG.

FIG. 3 is a view corresponding to FIG. 2 according to a second embodiment.

FIG. 4 is a view corresponding to FIG. 2 according to a third embodiment.

[Explanation of symbols]

2 ... Cylinder, 2a ... Inner peripheral surface, 3 ... Rotor, 4a ... Outer peripheral surface, 6 ... Feed gallery, 6a ... Circular groove fuel supply port,
7 ... Fuel supply passage, 8 ... Fuel suction passage, 9 ... Suction port, 1
0 ... Electromagnetic switching spill valve, 15 ... Pressurizing plunger (pressurizing means), 16 ... Pressurizing chamber (pressurizing means), 17 ... Inner cam (pressurizing means), 18 ... Fuel discharge passage, 19 ... Pressurizing passage ( Pressurizing means), 20 ... Discharge port, 21 ... Fuel distribution passage, 23 ... Bent portion, 24 ... Introducing hole (introducing portion), 24a ...
Extension center line, 25 ... Ejection hole (ejection part), 25a ... Extension center line, 26 ... Opening port, C ... Rotor rotation center line.

Claims (2)

[Claims] 1. A fuel from a fuel intake passage provided on a rotation center line in a rotor rotating in a cylinder is pressurized by a pressurizing means in the rotor, and this pressurized fuel is discharged as the rotor rotates. In a distribution type fuel injection pump that distributes pressure to each fuel distribution passage in a cylinder from a suction port provided in a rotor between a fuel supply port provided in an inner peripheral surface of the cylinder and a fuel suction passage in a rotor. The port is bent at a position eccentric to the center of rotation of the rotor,
A distribution type fuel injection pump comprising: an introduction portion extending from the outer peripheral surface of the rotor facing the fuel supply port to the bent portion; and a discharge portion extending from the bent portion to the fuel intake passage. 2. The distributed fuel injection pump according to claim 1, wherein the fuel supply port is a circumferential groove that faces the entire outer peripheral surface of the rotor, and the introduction portion of the suction port that communicates with this fuel supply port on the outer peripheral surface of the rotor. The distribution type fuel injection pump is characterized in that the opening port of the above is opened toward the rotational direction side of the rotor along the tangent line contacting the outer peripheral surface of the rotor at the opening port.