JPH0433414Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a fuel injection device for an internal fuel engine,
The fuel injection valve is connected via a supply line to a fuel supply device from which it is supplied with fuel, and the fuel injection process is controlled in time and in dependence on engine operating characteristics. It relates to a type equipped with a quantitative control mechanism.

“Schiff und Hafen／Kommandobrücke”
In a fuel injection device of this type known from March 1981, Volume 33, Page 40, a fuel injection pump with a pump plunger is provided. The pump plunger is provided with an inclined or straight-running control edge for controlling the fuel injection start point and the fuel injection end point. Each control edge corresponds to a defined load range and is designed to provide optimum fuel consumption in the respective load range. Depending on such a control edge, by rotating the pump plunger, it is possible to advance or delay the start and end points of fuel injection, and also to change the amount of fuel to be injected.

However, the fuel injection start point, the fuel injection end point, and the amount of fuel to be injected are limited by a fixed relationship between the control edges, and can only be changed within a predetermined, unchangeable relationship. . In other words, there is a drawback that at a predetermined fuel injection start point, the fuel injection end point and thus the fuel injection amount are determined in relation to the crank angle.

The object of the invention is therefore to improve a fuel injection system of the type mentioned at the outset in such a way that it is possible to obtain satisfactory fuel consumption not only in the partial load range but also in the entire load range. be.

According to the present invention, this problem has been solved by the features described in claim 1 of the utility model registration claim. Advantageous embodiments of the fuel injection device of the present invention as set forth in claim 1 of the utility model registration can be obtained by the structures described in the second and subsequent claims of the utility model registration.

With this configuration of the fuel injection device of the present invention, the fuel injection start point, the fuel injection end point, and the amount of fuel to be injected can be adjusted independently of each other. It has become possible to obtain perfect fuel consumption.

Next, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a fuel injection device associated with a cylinder of an internal combustion engine. This fuel injection device is provided with a fuel injection pump 1, and this fuel injection pump 1 supplies fuel, for example, heavy oil, to a fuel injection valve 3 connected via a supply pipe 2 at a high pressure of several hundred kgf/cm ² or more. For example, it is used to supply at high pressures from 1020 kgf/cm ² to 1326 kgf/cm ² . A pump cylinder 5 is inserted into the pump casing 4 . A two-part valve holder 6 for the delivery valve 7 adjoins the upper part of this pump cylinder 5 .
This discharge valve 7 is incorporated into the pump discharge hole 8. Since the valve holder 6 is screwed to the pump casing 4, the pump cylinder 5 is also fixed to the pump casing 4. Furthermore, the fuel injection pump 1 is provided with a pump plunger 10 which is controlled by a fuel control cam 9 and moves back and forth within the pump cylinder 5. The pump plunger 10 is rotatable and has on its end side an inclined control edge 11 which determines the injection start point of each fuel injection process. By means of this control edge 11, opening and closing of the inflow passage 12 connecting the pump chamber 13 and the fuel storage chamber 14 can be controlled during operation of the fuel injection pump 1. This fuel storage chamber 14 is connected via a supply conduit 15 to a fuel supply device.
In its simplest form, this fuel supply device has a fuel tank 16;
6 through a supply conduit 15 to the fuel storage chamber 1
4 may also be provided. The pump plunger 10 has a pressing pin 18
is fixed to the holding member 19 of the push spring 20. This push spring 20 is inserted between a radially projecting flange 21 of a holding member 19 configured in the shape of a bowl and a support surface 22 formed in the pump casing 4 and spaced apart from the holding member 19 in the axial direction. There is austerity. This pressing pin 18 is a holding member 19
and a hole 24 formed in the pump casing 4 and forming a connecting member between the pump plunger 10 and the pump plunger 10.
It also forms a connecting member for the tappet 23 guided therein. This tappet 23 is brought into contact with the fuel control cam 9 via a roller 25 supported thereon. To rotate the pump plunger 10, for example, teeth 26 are integrally formed on the pump plunger 10, as can be seen from FIG.
A device is provided having the following. A control rod 27 is toothed in this tooth 26 and is connected to an adjustment and control mechanism 28 as schematically shown in FIG.

The pump plunger 10 has, in addition to the teeth 26 and the control edge 11, a relief passage branching off from the control edge 11. This relief passage is formed by the longitudinal groove 29 and the control edge 1.
1 and a circumferential groove 30 separated somewhat in the axial direction. The pressure in the pump chamber 13 is released when the circumferential groove 30 is in the inlet passage 1 during the discharge process of the pump plunger 10.
It starts at the same time as passing 2.

The fuel injection pump 1 of the type described above can supply fuel to the fuel injection valve 3 connected thereto for each injection process. The fuel injection start point is determined by this control edge 11 on the pump plunger 10, and by rotating the pump plunger 10, the fuel injection start point can be made earlier or later. Furthermore, with this fuel injection pump 1, fuel having predetermined pressure change characteristics can be prepared at the start of each fuel injection. Such a fuel injection pump 1
The relationship achieved is clear from the pressure-time diagram shown in FIG. In this pressure-time diagram, point A indicates the earliest possible fuel injection start point, while point B indicates the latest fuel injection start point. Number 3 in Figure 2
The line indicated by 1 is a pressure characteristic curve during the discharge process of the fuel injection pump 1. This pressure characteristic curve 3
Point 32 on top 1 indicates the point and pressure level at which the fuel injection valve 3 opens and the fuel injection process begins.

According to a feature of the invention, a control mechanism 34 is provided in the supply conduit 2 extending between the fuel injection pump 1 and the fuel injection valve 3.
A built-in control conduit 33 is connected. This control mechanism 34 is provided with a control plunger 35 . This control plunger 35 is synchronized with the fuel injection process on the fuel injection pump side and, depending on its axial position, shuts off or opens the control line 33. Furthermore, this control plunger 35 is rotatable and has an inclined control edge 36 . By means of this control edge 36, depending on the rotational position of the pump plunger 35, it is possible to bring the end of each fuel injection process earlier or later and/or to vary the amount of fuel to be injected.

This control conduit 33 is connected to the fuel tank 16. Furthermore, the cross-section of this control conduit 33 is significantly smaller, at least in the part upstream of the control mechanism 34, than the cross-section of the supply conduit 2 leading to the fuel injection valve 3, the degree of reduction being approximately 1/4 to 10 times smaller.
That's up to 1/2.

The control mechanism 34 is constituted by a fuel injection pump whose function has been changed and whose structure has been slightly changed, and this fuel injection pump can control the fuel sent to the fuel injection valve according to the purpose. The function has been converted to .

According to the present invention, the fuel injection pump constituting the control mechanism 34 is the fuel injection pump 1 that generates the necessary fuel pressure at a high pressure of, for example, 1020 kgf/cm ² or more.
It is significantly smaller than the . Furthermore, the pump chamber of the fuel injection pump constituting this control mechanism 34 has been converted into a pressure relief chamber 37, the suction hole has been converted into a relief hole 38, and the suction chamber has been converted into a pressure relief chamber 39. This pressure relief chamber 39
A portion of the control conduit 33 that leads to the fuel tank 16 branches off from the fuel tank 16 .

The fuel injection pump constituting this control mechanism 34 has a pump casing 40. A pump cylinder 41 is inserted into this pump casing 40. This pump cylinder 41 is connected to a pump casing 4 which continues to the upper part of this pump cylinder 41.
It is held in a predetermined installed position by a connecting piece 42 fixed to 1. This connection piece 42 is followed by the part of the control conduit 33 in front of the control mechanism 34 . This control conduit 33 leads inside the connecting piece 42 into a bore 43 , which opens into the pressure relief chamber 37 . The control plunger 35, which reciprocates within the pump cylinder 41, has a control edge 36 which is axially offset relative to the end face 44 and extends obliquely to the plunger axis. This control edge 3
6 determines the end point of the fuel injection process. This inclined control edge 36 is connected to the control plunger 3.
It is formed by the upper side wall of the circumferential groove 57 at 5. This circumferential groove 57 is connected to the pressure relief chamber 37 via a vertical groove 58.

The control plunger 35 is fixed by a pressure pin 45 to a holding member 46 of a pressure spring 47. This push spring 47 is connected to a radially projecting flange 48 of a holding member 46 configured in a bowl shape.
and a support surface 49 formed in the pump casing 40 at a distance from the pump casing 40 . The pressure pin 45 forms a connection between the holding element 46 and the control plunger 35, and also for a plunger 50 which is guided in a suitably formed bore 51 in the pump housing 40. A roller 52 is rotatably supported on the plunger 50 and brought into contact with a control cam 53. This control cam 53 is mounted on a shaft driven by the drive shaft of the internal combustion engine and operates the control plunger 35 synchronously with the discharge process of the fuel injection pump 1. However, the control plunger 35 can also be actuated in another way, for example hydraulically, instead of by means of a control cam. Furthermore, this control plunger 35
is provided with a rotation mechanism having teeth 54 formed on this control plunger 35, for example. A control rod 55, which is axially movably supported in the pump casing 40, meshes with the teeth 54. Furthermore, this control rod 55 is connected to a control and regulating mechanism 56, which is shown only schematically.

The pump plunger 10 of the fuel injection pump 1 and the control plunger 35 of the control mechanism 34 are activated simultaneously or slightly earlier when the inlet passage 12 of the fuel injection pump 1 is shut off by the control lip 11. The relief hole 38 is also controlled by the plunger 35
are moved synchronously with respect to each other in such a manner that they are decoupled and controlled by the end faces 44 of. This ensures that the supply conduit 2 is "liquid-tight" at the beginning of the fuel delivery process by the fuel injection pump 1, and that the fuel injection process does not have any undesirable influence on the injection start point and the pressure change characteristics. It is guaranteed that it will pass. In this state, the escape hole 38 of the control mechanism 34
are the end face 44 and control edge 36 of the control plunger 35.
It is maintained as long as it is covered by the outer circumferential surface between the Only after a further upward movement of the control plunger 35 opens the relief hole 38 and thus the control line 33 again does the control mechanism 34 take part in the fuel delivery and injection process. In this case, the pressure in the supply conduit 2 leading to the fuel injection valve 3 drops sharply, so that the fuel injection valve 3 is closed and the fuel injection process is terminated.

The control edge 36 thus controls the fuel injection process. The configuration of the control edge 36 tilted with respect to the plunger axis and the rotation of the control plunger 35 change each fuel injection process to make the injection end point earlier or later. I can do it.

Furthermore, if not only the control lip 36 of the control mechanism 34 but also the control lip 11 of the fuel injection pump 1 is rotatable, the amount of fuel to be injected can also be varied.

This total variability is evident from FIG. This pressure-time diagram shows the same relationships as in FIG. 2, but in addition shows the effect exerted by the action of the control mechanism 34 on the fuel injection process.

In the diagram of FIG. 3, point C indicates the earliest end of the fuel injection process controllable by control edge 36 of control mechanism 34, and point D indicates the earliest end of the fuel injection process controllable by control edge 36 of control mechanism 34. Indicates the latest end point.

From the difference in area between the hatched surfaces E and F, it can be seen that the amount of fuel to be injected per fuel injection process is determined by the control edge 11 of the fuel injection pump 1 and the control mechanism 34.
It can be seen how the amount is increased or decreased by the adjustability of the control edge 36 of.

The fact that the start and end times of the fuel injection process and the amount of fuel to be injected can be adjusted within such large and large ranges makes it possible to adjust the position of the control edge in a fine manner as well as to control any load on the internal combustion engine. You will be able to get an impeccable fuel consumption in the range.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing one embodiment of the fuel injection device according to the present invention, Fig. 2 is a time/pressure diagram showing possible changes in the fuel injection start point on the fuel injection pump side, and Fig. 3 is a fuel injection process. FIG. 3 is a time/pressure diagram showing the control on the control mechanism side and the amount of fuel to be injected with respect to the end point of time. 1... Fuel injection pump, 2... Supply conduit, 3...
...Fuel injection valve, 4...Pump casing, 5...
Pump cylinder, 6...Valve holding body, 7...Discharge valve, 8...Pump discharge hole, 9...Fuel control cam,
10... Pump plunger, 11... Control edge, 1
2... Inflow passage, 13... Pump chamber, 14... Fuel storage chamber, 15... Supply conduit, 16... Fuel tank, 17... Fuel feed pump, 18... Pressing pin, 19... Holding member, 20 ...Press spring, 2
1... Flange, 22... Support surface, 23... Tappet, 24... Hole, 25... Roller, 26...
Teeth, 27...Control rod, 28...Adjustment and control mechanism, 29...Vertical groove, 30...Peripheral groove, 31...Pressure characteristic curve, 32...Point, 33...Control conduit, 34
...Control mechanism, 35...Control plunger, 36...
...Control edge, 37...Pressure chamber, 38...Escape hole,
39...Pressure relief chamber, 40...Pump casing, 4
1... Pump cylinder, 42... Connection piece, 43...
... Hole, 44 ... End surface, 45 ... Press pin, 46 ...
...Holding member, 47...Press spring, 48...Flange, 49...Supporting surface, 50...Tappet, 51...
... Hole, 52 ... Roller, 53 ... Control cam, 54
... Teeth, 55 ... Control rod, 56 ... Control and adjustment mechanism, 57 ... Circumferential groove, 58 ... Vertical groove.

Claims (1)

[Claims for Utility Model Registration] 1. A fuel injection device for an internal combustion engine, in which one injection valve 3 is provided.
a pump plunger 10 which is connected via a supply conduit 2 to an injection pump 1 and which is controlled by a cam 9;
, the pump plunger 10 has an inclined control edge 11 for determining the injection start point and is rotatable to change the injection start point, and in the fuel injection device further comprises:
In a type in which a control mechanism 34 separate from the pump plunger 10 is provided, which changes the injection end point independently of the injection start point, (a) between the injection pump 1 and the injection valve 3; A control conduit 33 that is led back to the unpressurized fuel tank 16 is connected to the supply conduit 2 extending from ^{A second injection} pump, which is significantly smaller than the injection pump 1, has a structure substantially corresponding to the injection pump 1, which generates a high injection pressure of 2 or more.
(c) The function of the second injection pump is converted to the first injection pump 1 as described in a, b, c and d below; a. In the second injection pump, a chamber corresponding to the pump chamber 13 of the first injection pump 1 is a pressure relief chamber 37, and control is conducted into the pressure relief chamber 37 and returned to the fuel tank 16. a conduit 33 is connected, b a passage in the second injection pump corresponding to the inflow passage 12 of the first injection pump 1 is a relief hole 38; c a first injection pump in the second injection pump; A chamber corresponding to the fuel storage chamber 14 of the injection pump 1 of d is a decompression chamber 39, and a plunger of the second injection pump corresponding to the pump plunger 10 of the first injection pump 1 is a chamber of the second injection pump. The control conduit 3 is actuated synchronously with the dispensing process and depending on the axial position.
control plunger 35 for blocking or opening 3;
, the control plunger 35 has an inclined control edge 36 and is rotatable, and depending on the rotational position of the control plunger 35, the injection end point is adjusted earlier or later, and the fuel is A fuel injection device for an internal combustion engine, characterized in that the injection amount can be changed. 2. the cross-section of the control conduit 33 is significantly smaller than the cross-section of the supply conduit 2 leading to the fuel injection valve 3, at least in the part before the control mechanism 34;
A fuel injection device according to claim 1 of the utility model registration claim. 3. A control cam 53 or another actuating member for actuating the control plunger 35 of the fuel injection pump constituting the control mechanism 34 is provided, and the control plunger 35 is actuated by the control cam 53 or the actuating member. The fuel injection device according to claim 1 or 2, which is operated synchronously with the discharge process of the fuel injection pump 1. 4 Rotation mechanisms 54 and 55 for rotating the control plunger 35 of the second fuel injection pump constituting the control mechanism 34, and the rotation mechanism 5
4, 55. The fuel injection device according to any one of claims 1 to 3, which is provided with a control and adjustment mechanism 56 for operating the fuel injection device 4 and 55.