JPH0444823Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an injection fuel control device for a fuel injection pump for a diesel engine.

Prior Art A hydraulic injection fuel control device as shown in FIG. 1 is known.

That is, the piston rod 3 of the power cylinder 2 is connected to the control rack 1 that increases and decreases the amount of fuel injected from the fuel injection pump, and the extension chamber 2a and contraction chamber 2 are
At the same time, the spool 6 of the valve 5 is slid by the flyweight 7 and the spring 8, and the flyweight 7
is connected to the rotating part via the cylinder 9 of the valve 5, and also connects the receiving piece 11 of the spring 8 to the control lever 12, and is also connected to the control rack 1 via the link mechanism A.

Then, the control lever 12 is used to increase or decrease the mounting load of the spring 8, and when the mounting load and the centrifugal force of the flyweight 7 are balanced, the spool 6 is at the position shown in the figure, and the inlet port 13 and the first outlet port 14 are connected to each other. communicates with each other, and the second outlet port 15 and drain port 16 are blocked, so the piston rod 3 of the power piston 2 is stopped at the position shown, and the control rack 1 is maintained at a predetermined position.

If the engine speed increases from the above-mentioned state and the centrifugal force of the flyweights 7 increases, or if the control lever 12 is operated in the direction of decreasing the injection amount (arrow a), the mounting load of the spring 8 decreases.
The spool 6 moves upward to the second outlet port 15
and the drain port 16, the discharge pressure oil of the pump 4 is supplied to the contraction chamber 2b, the piston rod 3 contracts, and the control rack 1 moves in the direction of decreasing the injection amount (arrow b).

As a result, the engine speed decreases and the centrifugal force of the flyweight 7 decreases, which is balanced with the mounting load of the spring 8, and the spool 6 returns to the state shown in FIG. 1, and the control rack 1 stops.

At this time, when the control rack 1 moves in the direction of decreasing the injection amount, the receiving piece 11 moves slightly in the direction of arrow c via the link mechanism A, and the mounting load of the spring 8 increases slightly.
The control rack 1 stops at a position where the centrifugal force of the fly weight 7 and the mounting load slightly larger than the mounting load set in are balanced.

Also, if the engine speed decreases from the state shown in Fig. 1 and the centrifugal force of the flyweights 7 decreases, or if the control lever 12 is operated in the direction of increasing the injection amount (arrow d) and the mounting load of the spring 8 increases. Since the spool 6 moves downward and communicates the inlet port 13 with the first and second outlet ports 14 and 15, the pressure oil discharged from the pump 4 is supplied to the extension chamber 2a and contraction chamber 2b of the power cylinder 2. The piston rod 3 expands due to the pressure receiving area difference, and the control rack 1 moves in the direction of increasing the injection amount (arrow e).

As a result, the engine speed increases and the centrifugal force of the flyweight 7 increases, and when this balances out with the mounting load of the spring 8, the spool 6 returns to the state shown in FIG. 1 and the control rack 1 stops.

At this time, as described above, as the control rack 1 moves in the direction of increasing the injection amount, the receiving piece 11 moves in the direction of the arrow f via the link mechanism A, and the mounting load of the spring 8 is slightly reduced, so that the control lever The control rack 1 stops at a position where the mounting load, which is slightly smaller than the mounting load set in step 12, and the centrifugal force of the flyweight 7 are balanced.

As described above, according to the hydraulic injection amount control device shown in FIG. When the control lever 12 is operated, the injection amount corresponds to a mounting load that is slightly larger than the mounting load of the spring 8 set by the control lever 12, and when the control lever 12 is operated in the direction of increasing the injection amount, the mounting load is slightly smaller than the mounting load of the spring 8 that has been set. The injection amount is commensurate with that.

However, with the above-mentioned structure, the maximum amount of movement of the piston rod 3 of the power cylinder 2 is determined by the engine speed, so the maximum amount of injection is also determined, and it is possible to improve torque rise or adjust the amount of injection when starting the engine. Since the torque cannot be increased, it cannot be applied to engines such as civil engineering machines that require a large torque rise, and problems such as poor engine startability occur.

Purpose of the invention: To be able to change the maximum amount of injection by changing the maximum amount of movement of the piston rod of the power cylinder according to the engine speed, thereby improving torque rise and increasing the amount of injection when starting the engine. With the goal.

Composition of the device The maximum amount of movement of the piston rod of the power cylinder can be changed by the mounting load of the injection quantity setting spring and the centrifugal force of the injection quantity setting flyweight, and by changing the mounting load of the injection quantity setting spring. The maximum amount of movement of the power cylinder's piston rod can be changed depending on the engine speed.

Embodiment FIG. 2 is an explanatory diagram of the configuration of a hydraulic injection fuel control device according to this embodiment, and differences from the hydraulic injection fuel control device shown in FIG. 1 will be explained.

The valve 5 has only a second outlet port 15, and the second outlet port 15 is connected to the extension chamber 2a of the power cylinder 2, and the piston rod 3 is biased in the contraction direction by a spring 20.

Reference numeral 21 designates an auxiliary valve, in which a spool 23 is inserted into the cylinder 22, and its extension chamber 21a is connected to the extension chamber 2a of the power cylinder 2 via a conduit 24, and its outlet port 25 is connected to the spool 23. The outlet port 25 is in communication with the drain.

The cylinder 22 is connected to the piston rod 3, that is, the control rack 1, by a guide arm 26, and the spool 23 is moved by the centrifugal force of the injection amount setting flyweight 27 and the mounting load of the injection amount setting spring 28, and is balanced. Stop at a position.

When the centrifugal force of the fly weight 7 and the spring 8 balance, the second outlet port 15 is blocked and the piston rod 3 stops, and when the centrifugal force of the fly weight 7 increases, the second outlet port 15
The piston rod 3 communicates with the drain port 16.
is contracted by the spring 20 and the centrifugal force of the flyweight 7 becomes smaller, the inlet port 13 and the second outlet port 15 communicate with each other, and the piston rod 3 expands.
As in the conventional case, the injection amount corresponds to the operating position of the control lever 12.

At this time, since the spool 23 of the auxiliary valve 21 moves with the movement of the control rack 3, the engine speed increases or decreases, and the centrifugal force of the injection amount setting flyweight 27 increases or decreases, causing the spool 23 to move. Even in this case, the outlet port 25 and the extension chamber 21a do not communicate with each other.

On the other hand, when the centrifugal force of the injection amount setting flyweight 27 becomes larger than the mounting load of the injection amount setting spring 28, the spool 23 moves upward, the outlet port 25 and the extension chamber 21a communicate with each other, and the power cylinder 2 expands. Since the pressure oil in the chamber 2a flows to the drain, the inlet port 13 of the valve 5 and the second
Even if the outlet port 15 is in communication, the piston rod 3 of the power cylinder 2 is stopped and the control rack 1 does not move any further in the direction of increasing the injection amount (arrow e).

Since it is like this, the injection amount set spring 2
By changing the mounting load 8, the maximum movement amount of the piston rod 3 of the power cylinder 2 can be changed according to the engine speed, and the maximum injection amount can be changed.

Therefore, the torque rise can be improved and the injection amount can be increased when starting the engine.

In other words, it is possible to increase the difference between the engine speed at maximum output and the maximum engine speed, and increase the output when the engine speed decreases, so it is possible to increase the torque rise and increase the power cylinder 2 when starting the engine. The extension stroke is increased to increase the amount of movement of the control rack 1 in the direction of increasing the injection amount,
The injection amount can be increased and engine startability can be improved.

Further, as shown in FIG. 3, the guide arm 26
It is also possible to install a boost convencator 29 in the engine and control the injection amount according to the boost pressure of the engine.

FIG. 4 shows another embodiment, in which the power cylinder 2
The cylinder 30 is formed with an inlet port 31 and an outlet port 32, and the piston 33 is formed with an inclined notch 34, and when the piston 33 moves upward, the notch 34 opens to the outlet port 32. Then, the extension chamber 2a communicates with the drain and the piston 33
At the same time as stopping the upward movement of the cylinder 30
By rotating the piston 33 to change the position of the outlet port 32, the position of the piston 33 where the notch 34 and the outlet port 32 open can be changed.
They are connected via a link mechanism 36 so as to be rotated by the vertical movement of a movable piece 35 that is moved by the mounting load and the centrifugal force of the injection amount setting flyweight 27.

As a result, the maximum amount of movement of the piston rod 3 of the power cylinder 2 can be changed in accordance with the engine speed by changing the mounting load of the injection amount set spring 28, as described above, and the maximum injection amount can be changed. .

FIG. 5 shows yet another embodiment, in which a drain hole 37 is formed across the piston 33 of the power cylinder 2 and the piston rod 3, and the drain hole 37 is connected to the extension chamber 2a by a hole 39 of the piston 38. The piston 38 is connected to the movable piece 35 via a link 40.

In this way, the piston 38 can be moved by the centrifugal force of the injection amount setting flyweight 27 and the mounting load of the injection amount setting spring 28, and the extension chamber 2a and the drain hole 37 can be disconnected from each other. By changing the mounting load of the set spring 28, the power cylinder 2 can be adjusted according to the engine speed.
By changing the maximum movement amount of the piston rod 3, the maximum injection amount can be changed.

The mounting load of the injection quantity set spring 28 can be changed by means of moving the spring receiver using a set screw, moving the spring receiver using a multi-stage cam, moving the spring receiver using pressure oil, etc. is possible.

Effects of the invention: By changing the mounting load of the injection amount set spring 28, the maximum amount of movement of the piston rod 3 of the power cylinder 2 can be changed, so the maximum injection amount can be changed according to the engine speed, improving torque rise. Alternatively, the injection amount can be increased when starting the engine to improve engine startability.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional example, FIG. 2 is an explanatory diagram of the configuration of a hydraulic injection fuel control device showing an embodiment of the present invention, FIG. 3 is an explanatory diagram of a partially modified example thereof, and FIG.
5A and 5B are explanatory diagrams of configurations of different embodiments, respectively. 1 is a control rack, 2 is a power cylinder, 3 is a piston rod, 4 is a pump, 5 is a valve,
6 is a spool, 7 is a fly weight, 8 is a spring, 12 is a control lever, 27 is an injection amount setting fly weight, and 28 is an injection amount setting spring.

Claims (1)

[Scope of utility model registration request] A control rack 1 for controlling the injection amount is connected to a piston rod 3 of a power cylinder 2, and a valve 5 controls the supply of pressure oil from a pump 4 to the power cylinder 2, and a spool 6 of the valve 5 is connected to a control lever 12. The piston rod 3 of the power cylinder 2 is moved by the centrifugal force of the spring 8 and the fly weight 7, and the maximum movement amount of the piston rod 3 of the power cylinder 2 is set by the mounting load of the injection amount set spring 28 and the injection amount set fly. An injection fuel control device characterized in that it can be changed by the centrifugal force of a weight 27.