JPH03260339A - Fuel injection device for internal combustion engine - Google Patents

Abstract

PURPOSE:To control mechanically surely a forced fuel supply start timing by providing a fuel injection pump having a sleeve control means or the like and a mechanical governor having a variable means or the like for varying the position of the control means. CONSTITUTION:When the rotational speed of a fuel injection pump 2 in a fuel injection device 1 is increased in proportion to the rotational speed of a Diesel engine, the weight stroke of a mechanical governor 6 is increased. Simultaneously, the other end of a floating lever 81 in an injection timing control mechanism 8 of the mechanical governor 6 is shifted leftward by a shift amount corresponding to the weight stroke. Thus, the floating lever 81 is rotated clockwise about a pivot 81c and a control sleeve 24, is lowered while a timing control rack 5 is shifted rightward so that the forced fuel supply start timing, i.e. firing timing is mechanically surely controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection device for an internal combustion engine, and in particular to a fuel injection device for a diesel engine used in a variable pre-stroke fuel injection pump. Technology] Japanese Utility Model Application Publication No. 196442/1983 discloses a control mechanism that controls the axial position of a control sleeve that changes the fuel pumping start timing (injection timing) depending on the axial position. In this control, a control member that changes the axial position of the control sleeve is operated by a hydraulic actuator. and,
This hydraulic actuator is controlled by a microcomputer based on detected values such as the rotational speed of the internal combustion engine.

Furthermore, the control mechanism disclosed in Japanese Utility Model Application Publication No. 63-196443 includes a flyweight whose centrifugal force changes depending on the rotational speed of the fuel injection pump, and an axial direction that changes in the centrifugal force of the flyweight. This utilizes a mechanical governor that has a displacement member that moves back and forth. That is, this control mechanism controls the annular position of the control sleeve by transmitting the amount of axial displacement of the displacement member related to the centrifugal force of the flyweight to the control member via the cable.

[Problems to be Solved by the Invention] However, the former control mechanism is expensive because it uses an expensive system such as a microcomputer that controls the hydraulic actuator.

Furthermore, in the latter control mechanism, it is not specifically disclosed how the displacement member, cable, and control member are connected, and how they are arranged relative to the mechanical governor. It was not possible to materialize the structure of the latter control mechanism.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel injection device for an internal combustion engine that is low in cost and is capable of mechanically and reliably controlling the start timing of pumping fuel.

[Means for Solving the Problems] The fuel injection device for an internal combustion engine of the present invention includes a plunger that is reciprocated in the axial direction by the internal combustion engine and pumps fuel, and a plunger that is slidably disposed around the outer circumference of the plunger. a fuel injection pump having a sleeve that changes the start timing of pumping fuel according to the axial position, and a control means that is connected to the sleeve and changes the axial position of the sleeve in response to the change in the position. a flyweight whose centrifugal force changes in accordance with a change in the rotational speed of the internal combustion engine; a variable means connected to the flyweight and which changes the position of the control means in response to a change in the centrifugal force of the flyweight; Adopted technical means with mechanical governor.

[Operation] The centrifugal force of the flyweight of the mechanical governor changes in response to changes in the rotational speed of the internal combustion engine.

Therefore, the variable means moves in response to changes in the centrifugal force of the flyweights, so that the position of the control means is changed by the variable means. In this way, as the position of the control means changes in response to the rotational speed of the internal combustion engine, the axial position of the sleeve also changes. Therefore, by changing the axial position of the sleeve, the timing at which fuel pumping starts is mechanically controlled in accordance with the rotational speed of the internal combustion engine.

U Effects of the Invention] The timing of starting pressure feeding of fuel, that is, the ignition timing, can be reliably controlled mechanically. This eliminates the need for an expensive system such as a microcomputer, resulting in lower costs than conventional devices.

[Example] The fuel injection device for an internal combustion engine of the present invention is shown in FIGS. 1 to 12.
Description will be made based on the embodiment shown in the figures.

1 to 4 show a first embodiment of the present invention.
This figure shows the main parts of a diesel engine fuel injection device, and FIG. 2 shows an all-speed mechanical governor.

A diesel engine fuel injection device 1 includes a size fuel injection pump 2 and an all-speed mechanical governor 6.
has.

The fuel injection pump 2 is a variable pre-stroke type fuel injection pump, and pumps the fuel supplied inside to a high-pressure pipe connected to the fuel injection pump 2 and a nozzle attached to each combustion chamber of the diesel engine. It is something.

This fuel injection pump 2 includes a drive mechanism 21, a cylinder 22
．． 7 langeer 23, a control sleeve 24, an injection amount control rack 4, and a timing control rack 5.

The drive mechanism 21 includes a camshaft 25 and a tappet 26.
has.

The camshaft 25 is rotationally driven by a diesel engine, and by rotating the cam 27,
6 to reciprocate the granger 23.

Further, the camshaft 25 rotationally drives the mechanical governor 6 in accordance with the rotational speed of the diesel engine.

The cylinder 22 has a fuel discharge port 28 formed at its upper end;
and has a shaft hole 29 formed inside.

The plunger 23 has a tubular shape and has a shaft hole 2 of the cylinder 22.
9 and is reciprocated in the vertical direction by a cam 27. This plunger 23 has a shaft hole 3 formed inside.
0, a lead 31 connected to this shaft hole 30 and formed on the outer periphery
, and a boat 32 that communicates with the shaft hole 30 and is formed below the lead 31 in the drawing.

The leads 31 are inclined at a predetermined angle so as to point upwardly to the right. The shaft hole 30 and the lead 31 function as a discharge passage for discharging the fuel in the shaft hole 29 of the cylinder 22 when the hole 33 of the control sleeve 24 and the lead 31 match (completion of pressure feeding). The shaft hole 30 and the boat 32 function as a supply passage for supplying fuel from the surroundings into the shaft hole 29 of the cylinder 22 through the shaft hole 30. In addition, the plunger 23
is rotationally controlled by the injection amount control rack 4,
Since the reed 31 is oriented upward to the left, rotating the lead 31 to the left will decrease the injection amount, and rotating it to the right will increase the injection amount.

The control sleeve 24 is a sleeve of this embodiment, has an annular shape, is disposed on the outer periphery of the plunger 23 so as to be slidable in the axial direction, and has a hole 33 that communicates between the inner periphery and the outer periphery.
and a fitting groove 34 connected to the timing control rack 5 on the outer periphery. As shown in FIG. 3, the fitting groove 34 is formed upward to the left. Therefore, when the timing control rack 5 moves to the left in the figure (to the right in FIG. 1), the control sleeve 24 descends, reducing the pre-stroke and advancing the timing at which fuel pumping starts. Further, when the timing control rack 5 moves to the right in the drawing (to the left in FIG. 1), the control sleeve 24 rises to increase the pre-stroke and delay the start of pumping of fuel. The pre-stroke means that the plunger 23 rises from the bottom dead center to move the boat 32 toward the control sleeve 24.
Refers to the amount of movement until it is closed by the inner wall of the

The injection amount control rack 4 is connected to the injection amount control mechanism 7 of the mechanical governor 6 and the plunger 23, and rotates the plunger 23 to change the positional relationship between the lead 31 and the hole 33, thereby ending fuel injection. season,
In other words, the fuel injection amount is controlled.

The timing control rack 5 is the control means of this embodiment, and has a control sleeve 24 at one end.
It has a first bin 51 that is fitted into the fitting groove 34, and a second bin 52 that is connected to the injection timing control mechanism 8 of the mechanical governor 6 at the other end. The timing control rack 5 changes the axially inner position 1 of the control sleeve 24 by reciprocating in the direction of the arrow shown in the figure, thereby controlling the timing at which fuel pumping starts.

Mechanical governor 6 includes fly weight 61 and shifter 6.
2. It has an injection amount control mechanism 7 and an injection timing control mechanism 8.

The flyweight 61 has a well-known structure, with one end connected to the camshaft 25 and the other end connected to the injection amount control mechanism 7 and the injection timing control mechanism 8 via a shifter 62. This flyweight 61 changes the axial position of the shifter 62 when the centrifugal force corresponding to the rotational speed of the camshaft 250, that is, the rotational speed of the fuel injection pump 2 overcomes the spring force of the spring 63 disposed on the outside. . In addition,
64 is a housing of the mechanical governor 6.

The injection amount control mechanism 7 has a well-known structure and is composed of a floating lever 71, a control lever 72, etc.
The injection amount control rack 4 and fly weight 61 are connected. Then, the injection amount control mechanism 7 controls the shifter 6
The amount of displacement in the reciprocating direction of the injection amount control rack 4 is controlled in accordance with the amount of displacement in the axial direction of the injection amount control rack 4.

The injection timing control mechanism 8 is the variable means of this embodiment, and
Floating lever 81 and control lever 8
This is a link mechanism consisting of two parts.

The floating lever 81 has an engagement groove 81a that engages the second bin 52 at one end, and an engagement groove 81b that engages the control lever 82 at the other end. The floating lever 81 rotates about the support shaft 81c when the shifter 62 moves in the axial direction, causing the timing control rack 5 to reciprocate in the left-right direction in the figure.

One end of the control lever 82 is engaged with the other end of the shifter 62, and the other end is rotatably supported by a support shaft 82a. Furthermore, a pin 82b that engages with an engagement groove 81b of the floating lever 81 is provided at one end of the control lever 82.

The operation of the fuel injection device 1 of this embodiment will be explained based on FIGS. 1 to 4.

The centrifugal force of the flyweight 61 of the mechanical governor 6 is
It increases as the rotational speed of the fuel injection pump 2, which is proportional to the rotational speed of the diesel engine, increases. in this way,
As the centrifugal force of the flyweights 61 increases, the shifter 62 moves to the left in the figure.
2, that is, the weight stroke S is the fourth
As shown in the graph of the figure, the rotational speed of the fuel injection pump 2 increases continuously as the rotational speed of the fuel injection pump 2 increases.

In this way, as the shifter 62 moves in the axial direction, the other end of the floating lever 81 moves to the left in the figure by a displacement amount corresponding to the weight stroke S.

Therefore, the floating lever 81 rotates clockwise around the support shaft 81c.

In this way, when the floating lever 81 rotates clockwise around the support shaft 81C, the timing control rack 5
moves to the right in the diagram.

Then, as the timing control rack 5 moves to the right in the drawing, the control sleeve 24 descends, so that the prestroke becomes smaller.

That is, the injection timing control mechanism 8 can mechanically advance the fuel pumping start timing, that is, the ignition timing, in response to an increase in the rotational speed of the fuel injection pump 2. Therefore, as shown in the graph of FIG. 4, the advance angle Δθ can be mechanically brought closer to the crank angle of the diesel engine in response to an increase in the rotational speed of the fuel injection pump 2. Therefore, no matter what the rotational speed of the diesel engine is, by keeping the ignition timing close to a constant value, an optimal combustion state can be obtained in the diesel engine.

Further, since advance characteristics can also be controlled by the mechanical governor 6, which normally controls only the fuel injection amount, expensive systems such as automatic timers and microcomputers are not required, resulting in lower costs than conventional devices.

5 to 7 show second to fourth embodiments of the present invention, FIG. 5 is a diagram showing a high-low speed mechanical governor, and FIG. 6 is a diagram showing an all-speed mechanical governor. 7 is a diagram showing a high-low speed mechanical governor. Functional objects that are the same as those in the first embodiment are given the same numbers.

In this way, the injection timing controller II8 that reciprocates the timing control rack 5 may be incorporated into any of the mechanical governors 6 shown in FIGS. 5 to 7.

FIG. 8 shows a fifth embodiment of the present invention, and is a diagram showing the main parts of a fuel injection device 1 for a diesel engine.

The timing control rack 5 has a first bin 53 fitted into the fitting groove 34 of the control sleeve 24 at one end, and a second bin 54 connected to the floating lever 91 at the other end. The timing control rack 5 changes the axial position of the control sleeve 24 by rotating in the direction of the arrow shown in the figure.

Further, the injection timing control mechanism 9 includes a floating lever 9
1 and a control lever 92.

The floating lever 91 has an engagement groove 91a at one end in which the second bin 54 engages, and a bin 91 rotatably supported by the control lever 92 at the other end.
It has b. When the shifter 62 is displaced in the axial direction, the floating lever 91 has an engaging groove 9 formed in the center.
By reciprocating around the bin 91d fixed to 1e, the second bin 54 is rotated as shown by the arrow in the figure. For this reason, the timing control rack 5
It rotates around this axis.

9 to 12 show sixth to ninth embodiments of the present invention.
An example is shown. FIG. 9 is a diagram showing an all-speed mechanical governor, and FIG. 10 is a diagram showing a high-low speed mechanical governor. Further, FIG. 11 is a diagram showing an all-speed mechanical governor, and FIG. 12 is a diagram showing a high-low speed mechanical governor. Components with the same functions as those in the fifth embodiment are given the same numbers.

In this way, the injection timing control mechanism 9 that rotationally drives the timing control rack 5 may be incorporated into various mechanical governors 6 shown in FIGS. 9 to 12.

In this embodiment, the link type variable means is composed of the floating lever and the control lever, but the variable means may be composed only of the floating lever.

In this embodiment, an annular control sleeve is used as the sleeve, but a cylindrical sleeve that is slightly longer in the axial direction may also be used as the sleeve.

In this embodiment, the drive mechanism is composed of a camshaft and a tappet, but the drive mechanism may be composed of only a camshaft.

[Brief explanation of drawings]

1 to 4 show a first embodiment of the present invention.
The figure is a perspective view showing the main parts of a diesel engine fuel injection system, Figure 2 is a schematic diagram showing an all-speed mechanical governor, Figure 3 is a front view of the control sleeve, and Figure 4 is the rotational speed of the fuel injection pump. It is a graph showing the relationship between the weight stroke and the advance angle. FIG. 5 is a schematic diagram showing the high-low speed mechanical governor adopted in the second embodiment of the present invention, FIG. 6 is a perspective view showing the all-speed mechanical governor adopted in the third embodiment of the present invention, and FIG. FIG. 7 is a schematic diagram showing a high-low speed mechanical governor employed in the fourth embodiment of the present invention. FIG. 8 is a perspective view showing the main parts of a diesel engine fuel injection device adopted in a fifth embodiment of the present invention. FIG. 9 is a schematic diagram showing an all-speed mechanical governor adopted in the sixth embodiment of the present invention, and FIG. 10 is a schematic diagram showing a high-low speed mechanical governor adopted in the seventh embodiment of the present invention. Figure 11 is a perspective view showing the all-speed mechanical governor adopted in the eighth embodiment of the present invention;
FIG. 2 is a schematic diagram showing a high-low speed mechanical governor employed in a ninth embodiment of the present invention. In the diagram 1...Fuel injection device f2 for diesel engine...
Fuel injection pump 5... Timing control rack (ILJ control means) 6... Mechanical governor 8
．． 9... Injection timing control mechanism (variable means) 23... Plunger 24... Control sleeve (sleeve) 61... Fly weight Fig. 2/

Claims (1)

[Claims] 1) (a) A plunger that is driven reciprocally in the axial direction by an internal combustion engine and pumps fuel; a sleeve that changes the pumping start timing; and a fuel injection pump that is connected to the sleeve and has a control means that changes the axial position of the sleeve in response to the change in position; (b) the rotational speed of the internal combustion engine; a flyweight whose centrifugal force changes in response to changes in the flyweight; and a mechanical governor connected to the flyweight and having variable means for changing the position of the control means in response to changes in the centrifugal force of the flyweight. Fuel injection device for internal combustion engines.