JPH03260342A - Fuel injection device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide surely a predetermined angle advancing property by means a mechanical control by providing a fuel injection pump having a sleeve control means or the like and a mechanical governor having a second variable means or the like for shifting the position of the control means or a first variable means according to an engine load. CONSTITUTION:When the adjusting screw 71 of the load angle advance adjusting mechanism 71 of a second variable means is operated, an adjusting lever 72 is rotated about a pivot 74. Thus, the cam 65 of the link mechanism 61 of a first variable means is rotated about an eccentric shaft 65c so that a position in which a cam face 65a abuts against a stopper 42 is shifted. However, even if the initial position of the cam 65 is shifted, a pin 65b engages with an engaging groove of a control lever 64. As a result, a shifter 52, a floating lever 62, respective control levers 63, 64 and cam 65 are shifted according to a centrifugal force of a fly weight 51, i.e. the rotational speed change of a fuel injection pump 2, so that positions of a timing control rack 4 and a control sleeve 24 are varied.

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 particularly to a fuel injection device for a diesel engine used in a variable prestroke fuel injection pump.

[Prior Art] Japanese Utility Model Application Publication No. 63-196442 discloses a control system for controlling the axial position of a control sleeve that changes the fuel pumping start timing (injection timing) according to the axial position. ing. This control mechanism operates a control means for changing the axial position of the control sleeve using 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 axial position of the control sleeve by transmitting the axial displacement 1 of the displacement member related to the centrifugal force of the flyweight to the control means 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.

In addition, in the latter control device, it is not specifically disclosed how the displacement member, cable, and control means are connected, and how they are arranged with respect to the mechanical governor. It was not possible to materialize the structure of the latter control mechanism. In other words, the latter control mechanism cannot be said to be capable of mechanically controlling the timing at which fuel pumping starts.

Furthermore, the former and latter controls 81 can advance the fuel pumping timing, that is, the ignition timing, from the crank angle of the internal combustion engine when the internal combustion engine is operated at full load (full throttle), for example. There wasn't. For this reason,
There has been a problem in that the fuel consumption rate decreases when the internal combustion engine is operated under full load.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel injection device for an internal combustion engine that can mechanically control the start timing of fuel pumping and that can obtain advance angle characteristics that correspond to the load condition of the internal combustion engine.

[Means for Solving the Problems] A fuel injection device for an internal combustion engine according to the present invention includes a plunger that is reciprocated in the axial direction by the internal combustion engine and pumps fuel, a plunger that is slidably disposed around the outer circumference of the plunger, A fuel injection pump having a sleeve that changes the timing at which to start pumping fuel depending on the axial position I, and a control means that is connected to the sleeve and controls the axial position of the sleeve in response to changes in the position. a flyweight whose centrifugal force changes in response to changes in the rotational speed of the internal combustion engine; a flyweight interposed between the control means and the flyweight to connect the control means and the flyweight; a first variable means for changing the position of the control means in response to a change in the centrifugal force of the weight; A technical means is adopted in which a mechanical governor having a second variable means for shifting the position of the control means or the first variable means in a connected state is biased.

[Operation] When the position of the control means or the first variable means is shifted by the second variable means in response to the load condition of the internal combustion engine while maintaining the state connected to the flyweight, the axial position of the sleeve is also shifted. In other words, since the fuel pumping start timing is controlled to correspond to the load condition of the internal combustion engine, no matter what the rotational speed during internal combustion m, the load of the internal combustion engine is An advance angle corresponding to the state can be obtained.

[Effects of the Invention] It is possible to mechanically control the timing to start pumping fuel, that is, the ignition timing. This eliminates the need for an expensive system such as a microcomputer, resulting in lower costs than conventional devices.

Furthermore, advance angle characteristics corresponding to the load condition of the internal combustion engine can be obtained.

[Example] A fuel injection device for internal combustion SarM according to the present invention will be described based on an example shown in FIGS. 1 to 8.

1 to 4 show a first embodiment of the present invention.
The figure is a diagram showing the main parts of a fuel injection device for a diesel engine.

The diesel engine fuel injection device 11 includes a fuel injection pump 2 and an all-speed mechanical governor 5.

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
, a plunger 23, a control sleeve 24, an injection amount control rack (not shown), and a timing control rack 4.

The drive machine #I21 has a camshaft 25 and a tappet 2.
It has 6.

The camshaft 25 is rotationally driven by a diesel engine, and by rotating the cam 27, the tappet 26 is rotated.
The plunger 23 is caused to reciprocate through the .

Further, the camshaft 25 rotationally drives the mechanical governor 5 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 serve as a supply passage for supplying fuel from the surroundings into the shaft hole 29 of the cylinder 22 through the shaft hole 30, and also serve as a supply passage for supplying fuel from the surroundings into the shaft hole 29 of the cylinder 22.
The reed 31 is placed in the injection amount control rack and is rotationally controlled, and since the lead 31 is upwardly oriented to the left, rotating the lead 31 to the left decreases the injection amount, and rotating it clockwise increases 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 the inner periphery with the outer periphery.
and a fitting groove 34 connected to the timing control rack 4 on the outer periphery.

When the timing control rack 4 rotates to the left, the control sleeve 24
is lowered to reduce the pre-stroke and start pumping fuel earlier. Moreover, the control sleeve 24 is
When the timing control rack 4 rotates clockwise, the control sleeve 24 rises, increasing the pre-stroke and delaying the start of pumping fuel. The prestroke refers to the amount of movement of the 7 langier 23 from the bottom dead center until the boat 32 is closed by the inner wall of the control sleeve 24.

The timing control rack 4 is the control means of this embodiment, and a control sleeve 24 is fitted around the outer periphery of the timing control rack 4.
A pin 41 that is fitted into the ll34 is disposed, and a stopper 42 that rotates integrally with the outer circumference t of the end portion is fitted. The stopper 42 is pressed toward the injection timing control mechanism 6 of the mechanical governor 5 by a safety spring 43.

The timing control rack 4 rotates in the direction of the arrow in the figure to change the axial position of the control sleeve 24, thereby controlling the timing at which fuel pumping starts.

The mechanical governor 5 has a flyweight 51. shifter 5
2. It has an injection amount control mechanism (not shown) and an injection timing control mechanism 6.

The flyweight 51 has a well-known structure and is attached to the camshaft 2.
5, connected to an injection amount control mechanism and an injection timing control mechanism 6. This flyweight 51 is connected to the camshaft 2
When the centrifugal force corresponding to the rotational speed of the shifter 5, that is, the rotational speed of the fuel injection pump 2, overcomes the spring force of the spring 53 disposed on the outside, the shifter 5 rotates as shown in the graph of FIG.
2, the displacement amount (weight stroke) of the injection amount control mechanism and the injection timing control mechanism 6 is changed.

Note that 54 is a housing of the mechanical governor 5.

The injection amount control mechanism controls the position of the injection I control rack with respect to the rotational speed of the fuel injection pump 2 as shown in the graph of FIG.

In the graph of FIG. 3, A represents the idling state of the diesel engine, and F represents the full load state (full throttle) of the diesel engine.

The injection timing control mechanism 6 includes a link mechanism 61 and a load advance adjustment mechanism 7.

The link mechanism 61 is the first variable means of this embodiment, and
Floating lever 62, control lever 63.
64 and a cam 65.

The floating lever 62 has a pin 62a that engages with the control lever 64 at one end, and an engagement groove 62b that engages with the control lever 63 at the other end.
has. This floating lever 62 is connected to the shifter 5
When the lever 2 is displaced in the axial direction, it is displaced in the rotational direction about the support shaft 62c, causing the control lever 64 to reciprocate in the axial direction.

The control lever 63 has one end engaged with the other end of the shifter 52, and the other end rotatably supported by the support shaft 63a. Furthermore, a pin 63b that engages with the engagement groove 62b of the floating lever 62 is integrally provided at one end of the control lever 63.

The control lever 64 has an engagement groove (not visible in the figure) that engages with the end of the cam 65 at one end, and a pin 62 of the floating lever 62 at the other end.
It has an engagement hole 64a that engages with a.

When the floating lever 62 rotates about the support 11h62c, the control lever 64 reciprocates in the axial direction and drives the cam 65 in the rotational direction.

The cam 65 has a cam surface 65a in contact with the tip of the stopper 42, and has a pin 65b at its end that engages with the engagement groove of the control lever 64. This cam 65 is
When the control lever 64 reciprocates in the axial direction, it rotates together with the eccentric shaft 65c, changing the position of the stopper 42 in the rotation direction, that is, the position of the timing control rack 4 in the rotation direction, to a position according to the cam shape. change to

The load advance angle adjustment mechanism 7 is the second variable means of this embodiment, and includes an adjustment screw 71, an adjustment lever 72, and a spring 7.
It has 3. The load advance adjustment mechanism 7 rotates the cam 65 to an initial position corresponding to the full load state of the internal combustion engine, thereby obtaining a load advance characteristic corresponding to the full load state of the internal combustion engine.

The adjusting screw 71 is manually operated to an axial position corresponding to the full load condition of the internal combustion engine.

The adjustment lever 72 has an eccentric shaft 6 having a cam 65 at one end.
5c, and the other end is connected to the tip of the adjustment screw γ1. This adjustment lever 72 is connected to the adjustment screw 7
The cam 65 rotates around the support shaft 74 in accordance with the axial position of the tip of the cam 65, thereby rotating the eccentric shaft 65c of the cam 65.

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

When the adjusting screw 71 is operated to an axial position corresponding to the full load state of the internal combustion engine, the adjusting lever 72 rotates to the left about the support shaft 14. Therefore, since the cam 65 rotates to the left around the eccentric shaft 65c, the initial value W of the rotation direction of the cam 65 (rotation position when the rotation speed of the fuel injection pump 2 is 0 rp-) is shifted. The contact position between the tip of the stopper 42 and the cam surface 65a of the cam 65 is shifted, and the initial position of the timing control rack 4 in the rotational direction is shifted downward in the drawing (in a direction that advances the crank angle of the diesel engine).

Note that even if the initial position of the cam 65 is shifted, since the pin 65b is engaged with the engagement groove of the control lever 64, the flyweight 51, shifter 52, floating lever 62, control lever 63, 64, and cam 65 are The connection status of is maintained. For this reason, the flyweight 51
The shifter 52, the floating lever 62, the control levers 63, 64, and the cam 65 move in response to changes in the rotational speed of the fuel injection pump 2 due to centrifugal force.

Therefore, the positions of the timing control rack 4 and the control sleeve 24 can be changed according to changes in the rotational speed of the fuel injection bong 12, so that the prestroke can be controlled according to changes in the rotational speed of the fuel injection pump 2.

Therefore, the idling state of the diesel engine (
The timing control rack 4 changes faster with respect to the rotational speed of the fuel injection pump 2 in the full load state (indicated by the broken line in FIG. 4) than in the case (indicated by the solid line in FIG. 4). For this reason, the prestroke also changes quickly, so
At any rotational speed of the diesel engine, the position of the control sleeve 24 corresponds to the desired advance characteristic required for full load conditions of the diesel engine.

Particularly in high-speed ranges where the diesel engine crankshaft rotates at high speeds, the fuel pumping timing, or ignition timing, can be advanced from the diesel engine crank angle, resulting in stable combustion even when the fuel injection amount is increased. This makes it possible to suppress the occurrence of nox and a decrease in fuel consumption.

Furthermore, the mechanical governor 5, which normally controls only the fuel injection amount, can mechanically control the fuel pumping start timing, that is, the ignition timing. This eliminates the need for expensive systems such as automatic timers and microcomputers, resulting in lower costs than conventional devices.

5 and 6 show a second embodiment of the present invention.
The figure shows the main parts of a fuel injection device 1 for a diesel engine.

Components with the same functions as those in the first embodiment are given the same numbers.

The fitting groove 34 of the control sleeve 24 of this embodiment is as follows:
As shown in FIG. 6, it is formed on the upper left side. Therefore, when the timing control rack 4 moves to the left in the figure (rightward in the figure in FIG. 5), the control sleeve 24 descends and reduces the prestroke, thereby controlling the timing at which the fuel pumping starts, that is, the crank angle of the diesel engine. Advance the ignition timing. Furthermore, when the timing control rack 4 moves to the right in the drawing (to the left in FIG. 5), the ignition timing becomes later than the crank angle of the diesel engine.

The other end of the timing control rack 4 of this embodiment is provided with a bin 45 that engages with a stopper 44 . This timing control rack 4 has a stopper 4.
4 rotates around the support shaft 46, the axial position of the control sleeve 24 can be changed by reciprocating in the axial direction.

Further, in this embodiment, the floating lever 62 and the cam 65 directly engage with each other without using the control lever 64.

7 and 8 show a third embodiment of the invention. 7th
The figure shows a load advance angle adjustment mechanism.

Components with the same functions as those in the first embodiment are given the same numbers.

The load advance angle adjuster 1118 is a second variable means of the present invention, and includes an adjustment lever 81, a spring 82, an actuator 83, and a control mechanism 84 for this actuator 83.
has.

The adjustment lever 81 is similar to that in the first embodiment, and when driven by the actuator 83, rotates around the support shaft 81a.

When the internal pressure rises above a predetermined pressure, the actuator 83 overcomes the biasing force of the spring 82 to change the position of the adjustment lever 81 in the rotational direction to a position corresponding to the full load (4/4 load) state of the diesel engine. Shift to

The control mechanism 84 includes a spill receiver 85, a throttle 86, and piping 87. The spill receiver 85 receives spill pressure discharged from the hole 33 of the control sleeve 24. Further, the spill pressure increases as the fuel injection amount (see the graph in FIG. 3) corresponding to the load state of the diesel engine increases.

The operation of this load advance angle adjuster PA8 will be briefly described.

Spill pressure dependent on the load condition of the diesel engine is taken from the spill receiver 85 and supplied to the interior of the actuator 83 via the throttle 86 . And actuator 8
The internal pressure of 3 is the specified pressure (Diesel engine 4
In order to rotate the adjustment lever 81 counterclockwise around the support shaft 81a when the pressure rises above the pressure corresponding to the load condition, the timing control rack 4 rotates counterclockwise and the control sleeve 24 moves downward in the figure. do. Therefore, the fuel pumping start timing is advanced by an advance angle Δθ corresponding to the 474 load condition of the diesel engine with respect to the crank angle.

Therefore, especially when the rotational speed of the fuel injection pump 2 is in a high speed range, that is, the rotational speed of the diesel engine is in a high speed range, the position of the control sleeve 24 can be adjusted to the desired progress required for the 4/4 load state of the diesel engine. It can be made to correspond to the angular characteristics.

In this embodiment, an all-speed mechanical governor is used as the mechanical governor, but a high-low speed mechanical governor may also be used.

In this embodiment, both the fuel injection amount and the fuel pumping start timing are controlled by the mechanical governor, but only the fuel pumping start timing may be controlled by the mechanical governor.

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

In this embodiment, the first variable means is a floating lever,
Although the control lever and the cam are used at the bottom of the tank, the first variable means may be replaced by only a floating lever.

In this embodiment, an actuator operated by an adjustment screw or spill pressure was used as the drive mechanism for the adjustment lever of the second variable means, but the drive mechanism is electrically operated by detecting the position of the injection amount control rack. An actuator may be used, or if a high-low speed mechanical governor is used, a drive mechanism may be used that drives the adjustment lever based on the throttle opening or the amount of operation of the accelerator pedal.

In this embodiment, the second variable means rotates the eccentric shaft of the cam, but the second variable means changes the position of the rod, timing control rack, stopper, rod, control lever, or floating lever connected to the flyweight. You can change it while maintaining it.

[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 fuel injection device for a diesel engine, Figure 2 is a graph showing the relationship between the rotational speed of the fuel injection pump and the weight stroke, and Figure 3 is a graph showing the relationship between the rotational speed of the fuel injection pump and the injection amount control. FIG. 4 is a graph showing the relationship between the rotational speed of the fuel injection pump and the position and advance angle of the timing control rack. 5 and 6 show a second embodiment of the present invention.
The figure is a perspective view showing the main parts of the fuel injection device for a diesel engine, and FIG. 6 is a front view of the control sleeve. 7 and 8 show a third embodiment of the present invention.
The figure is a perspective view showing the release mechanism, and FIG. 8 is a graph showing the relationship between the rotational speed and advance angle of the fuel injection pump. In the diagram

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 controls the axial position of the sleeve in response to changes in position; (b) the rotational speed of the internal combustion engine; A flyweight whose centrifugal force changes in response to a change in the centrifugal force of the flyweight; a first variable means for correspondingly varying the position of the control means; and a first variable means coupled to the control means or the first variable means and coupled to the flyweights in response to a load condition of the internal combustion engine. or a mechanical governor having a second variable means for shifting the position of the first variable means.