JPS63167035A - Fuel injection pump for diesel engine - Google Patents

Abstract

PURPOSE:To always insure starting ability regardless of variations in atmospheric pressure, by equipping a fuel injection pump formed with a start supercharging mechanism and a high ground correcting device for fuel injection quantity, with a control means adapted to control or stop the operation of the high ground correcting device, in the start supercharging range. CONSTITUTION:A fuel-injection pump 1 is equipped with a governor lever mechanism 6 formed with a start lever 8, tension lever 9 and a collector lever 10. This mechanism 6 slide-displaces a control sleeve 5 according to the total amount of force which acts on each of the levers 8-10, to vary the fuel injection quantity. This pump 1 is also equipped with a bellows device 20, adapted to move the sleeve 5 in the fuel decreasing direction according to a fall in atmospheric pressure. In this case, a control device is set to control the action of this bellow device 20. This control device is formed with an electromagnetic device 28 adapted to be excited in the start supercharging range, and constituted as rotating a lever 29 through a plunger 28a by the action of the electromagnetic device 28, and controls the high ground correction through moving a plunger 23 upward.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a starting supercharging device that performs fuel supercharging at the time of starting, and a starting supercharging device that performs starting supercharging that supercharges fuel at the time of starting. The present invention relates to a fuel injection device for a diesel engine that includes a high altitude correction device that reduces the amount of fuel to be injected.

(Prior Art) Conventionally known diesel engine ml injection pumps have a general structure, for example, as disclosed in U.S. Pat.
As disclosed in No. 5, there is a control sleeve that controls the fuel injection amount according to the amount of displacement, and a control sleeve that is linked to the accelerator pedal and biases the position of the control sleeve in the direction of increasing fuel according to the increase in the amount of depression of the accelerator pedal. a tension lever mechanism that displaces in accordance with the engine speed, a governor lever mechanism that engages with the governor sleeve and biases the position of the control sleeve in a fuel decreasing direction in response to an increase in the engine speed. We are prepared.

In this type of fuel injection pump, starting supercharging is performed as follows. That is, when starting the engine, the control sleeve is biased in the direction of increasing fuel by pressing the accelerator pedal. On the other hand, at this time, the governor sleeve, which urges the control sleeve in the direction of decreasing fuel, has little influence on the operation of the control sleeve due to the low engine speed, so a large amount of fuel is injected at the time of startup. . That is,
Start-up supercharging is performed, thereby improving ignition performance at start-up.

Then, after starting, as the engine speed increases, the control sleeve is gradually displaced in the direction of decreasing fuel due to the action of the governor sleeve, and the fuel injection amount is decreased. That is, starting supercharging is terminated when the engine speed increases to a predetermined value or more.

Further, the fuel injection amount of the diesel engine is configured not to exceed a maximum fuel injection amount that is set depending on the rotation speed in order to suppress the generation of smoke as much as possible. In this case, the state of smoke generation varies depending on the atmospheric pressure.
When the same amount of fuel is supplied, the amount of smoke generated increases as the pressure decreases, such as at high altitudes. Taking this relationship into account, we installed a high-altitude correction device for fuel injection amount that reduces the maximum fuel injection amount as the atmospheric pressure decreases, thereby reducing the amount of smoke generated regardless of changes in atmospheric pressure. A fuel injection pump has been proposed.

(Problem to be solved) However, the conventional high altitude correction device uniformly reduces the maximum fuel injection amount of the fuel injection pump depending on the atmospheric pressure, so for example, when starting at high altitude, , the high altitude correction device operates and reduces the amount of fuel injection.
A problem arises in that a sufficient amount of starting supercharging cannot be obtained, resulting in poor starting performance.

(Means for solving the problems) The present invention was constructed in view of the above circumstances, and
It is an object of the present invention to provide a fuel injection pump for a diesel engine that can reduce the amount of smoke produced and always ensure good startability regardless of changes in atmospheric pressure.

The fuel injection pump of the present invention includes a starting supercharging device that increases the amount of fuel supplied during startup, and a fuel injection amount control device that reduces the amount of fuel injected during high-altitude operation with low atmospheric pressure than during low-altitude operation under normal atmospheric pressure conditions. The fuel injection pump for a diesel engine is equipped with a high altitude correction device, and is characterized by comprising a control means for restricting or stopping the operation of the high altitude correction device in a starting supercharging region.

A fuel injection pump to which the present invention can be applied includes a normal starting supercharging mechanism and a high altitude correction mechanism. For example, the supercharging mechanism includes a fuel adjustment device that controls the fuel injection amount according to the amount of displacement, and a fuel adjustment device that works in conjunction with the accelerator pedal and changes the position of the fuel adjustment device in the direction of fuel increase in response to an increase in the amount of depression of the accelerator pedal. an accelerator-linked lever mechanism that moves the engine speed; a speed governor mechanism that moves according to the engine speed; It can be configured by providing a speed regulating lever mechanism.

With this configuration, when the engine is started, the fuel adjustment device is biased in the direction of increasing fuel by pressing the accelerator pedal. On the other hand, at this time, the governor sleeve, which urges the control sleeve in the fuel decreasing direction, has little influence on the operation of the control sleeve because the engine speed is low, so a large amount of fuel is injected to perform starting supercharging.

When the rotational speed increases, the speed regulating mechanism moves the fuel adjustment device in the direction of decreasing fuel against the biasing force of the accelerator-linked lever mechanism in the direction of increasing fuel. As a result, the fuel injection amount begins to decrease, and the starting supercharging state ends.

Further, the high altitude correction device can be configured by a bellows device that is displaced in accordance with atmospheric pressure, and a means for controlling the operation of the fuel adjustment device in response to the bellows device.

Further, in the present invention, a control means is provided for restricting or stopping the operation of the high altitude correction device at the time of starting. This control means can be composed of, for example, a solenoid valve, which is energized when a starting condition is detected by a key switch or the like, and limits and stops the operation of the above-mentioned high altitude correction device. It is configured to demagnetize when a rotation switch or the like detects that the engine speed has risen to a predetermined value or higher, for example, 7 oorpm, and has exited the starting state.

Further, the control means may be constructed by focusing on the fact that the oil pressure within the pump increases in proportion to the engine speed. In this case, a plunger is provided that is displaced according to the oil pressure inside the pump, and when the rotation speed is low, the operation of the high altitude correction device is restricted by the plunger, and when the rotation speed increases, that is, the oil pressure increases, the high altitude correction device is The plunger may be moved so that the correction device can operate.

(Effects of the Invention) According to the above configuration of the present invention, the operation of the high altitude correction device is restricted in the starting supercharging region as the atmospheric pressure decreases, so that sufficient starting supercharging fuel can be secured. Therefore, good startability can be obtained regardless of changes in atmospheric pressure.

In addition, the operation of the high altitude correction device is not restricted in normal operating conditions beyond the start-up period, so depending on changes in atmospheric pressure,
An appropriate maximum fuel injection amount can be set, and smoke generation can be effectively suppressed.

(Description of Examples) Examples of the present invention will be described below with reference to the drawings.

Referring to FIG. 1, a sectional view of a distribution type fuel injection pump to which the present invention can be applied is shown.

The pump 1 includes a drive shaft 2 that drives the pump 1 and a plunger 3 that supplies fuel. The drive shaft 2 and plunger 3 are connected via a cam disc 4. This cam disc 4 has the same number of cam faces as the number of cylinders in the engine. Further, the cam disc 4 is pressed against the drive disc 2a of the drive shaft 2 by a plunger spring 3a. Therefore, the plunger 3 reciprocates in conjunction with the rotation of the drive shaft.

The pump 1 also includes a control sleeve 5 that fits into the plunger 3 and changes the amount of fuel supplied according to the amount of displacement.

A pin hole 5a is formed in the control sleeve 5, and a ball head pin 7 attached to the lower end of the governor lever mechanism 6 is engaged with the pin hole 5a. The governor lever mechanism 6 includes a start lever 8, a tension lever 9, and a collector lever 10 that are integrally assembled, and is configured to be rotatable around a support shaft 11. Then, the governor lever mechanism 6 swings the rad pin 7 to the ball depending on the magnitude of the resultant force of the forces acting on the levers 8, 9 and 10, thereby displacing the control sleeve 5 left and right in the figure. to change the fuel injection l.

Since the collector lever 10 is supported by the support spring 12 at its lower part, it is in contact with the full load adjuster cylinder 5-10a.

One end of the tension lever 9 engages a control lever mechanism 13 that responds to actuation of the accelerator pedal. As the amount of depression of the accelerator pedal (not shown) increases, the control lever mechanism 13 moves to the left in the figure, and the upper end of the tension lever 9 rotates to the left. do. Therefore, the radbin 7 to the ball rotates to the right and urges the control sleeve 5 to the right. When the control sleeve 5 moves to the right, the fuel injection amount decreases.

Further, one end of the start lever 8 is connected to the governor sleeve 1.
It is designed to engage with the tip of 4.

The governor sleeve 14 is supported by the governor shaft 15 and engages with a flyweight 17 housed in a flyweight holder 16. As the engine speed increases, the flyweight 17 is rotated centrifugally. The force pushes the governor sleeve 14 to the right in the figure. As a result, the start lever 8 rotates to the right, and urges the control sleeve 5 to the left, that is, in the direction of fuel increase, via the rad pin 7 to the ball.

Further, a start idle spring 18 and a start spring 19 are interposed between the start lever 8 and the tension lever 9.
The springs 18 and 1
The interference is made by the magnitude of the elastic force of 9.

The start lever 8 and the tension lever 9 can rotate relative to each other around the support shaft 11 within the range of the elastic force of the start idle spring 18 and the start spring 19, but the force exceeding this range is When activated, the start lever 8 and the tension lever 9 will rotate together.

In this case, the control sleeve 5 is basically
The position is determined at a point where the biasing force of the start lever 8 in the fuel decreasing direction due to an increase in the rotational speed and the biasing force of the tension lever 9 in the fuel increasing direction due to an increase in the amount of accelerator pedal depression are harmonized, and the fuel injection amount is determined by this.

Furthermore, the pump 1 of this example is equipped with a bellows mechanism 20 that operates according to the magnitude of atmospheric pressure.
0 includes a chamber 21 that communicates with the atmosphere, a bellows body 22 disposed within the chamber 21 and sealed with a standard pressure gas, and a bellows body 22 that is attached to the bellows body 22 and rotates in the figure according to the movement of the bellows body 22. The plunger 23 is provided with a plunger 23 that moves up and down. Further, the bellows main body 22 is urged upward in the figure by a spring 24. The plunger 23 has a small diameter portion 23a in the middle.
It is equipped with A control arm 25 is engaged with the plunger 23 via a connecting pin 25a, and the control arm 25 is rotatably attached around a pin 27 fixed to a pump casing 26. .

The other end of the control arm 25 is engaged with one end of the tension lever 9.

When the atmospheric pressure introduced into the chamber 21 becomes lower than the gas pressure sealed inside the bellows body, the bellows body 22 resists the biasing force of the spring 24 according to the magnitude of the atmospheric pressure. and expands, pushing down the plunger 23. One end of the control arm 25 is normally engaged with the small diameter portion 23H of the plunger 23, but when the plunger 23 moves downward due to a decrease in atmospheric pressure,
Since the diameter of the contact portion of the connecting bin 25a becomes larger, the control arm 25 rotates to the left in the figure, causing the tension lever 9 to rotate to the right. That is, the bellows machine 120 moves the control sleeve 5 in the direction of decreasing fuel as the atmospheric pressure becomes lower, thereby performing the high altitude correction.

The pump 1 of this example is provided with a control device for controlling the operation of this high altitude correction device. This control device includes an electromagnetic device 28 and a pivot lever 29. The rotating lever 29 is rotatably supported around a pin 30, and one end thereof is adapted to engage with a plunger 28a that moves up and down of the electromagnetic device 28, and the other end is adapted to engage with a plunger 28a that moves up and down of the electromagnetic device 28. It is designed to engage with the lower end of the mW plunger 23. The electromagnetic device 28 pushes the plunger 28a downward when this solenoid is energized. This causes the lever 29 to rotate and urge the plunger 23 of the high altitude correction device upward, thereby limiting the operation of the high altitude correction device.

That is, when the electromagnetic device 28 is excited, the bellows mechanism 20 does not control the fuel injection amount according to the change in air pressure, but the control sleeve 5 is controlled according to the accelerator pedal and the rotation speed.

The solenoid of the electromagnetic device 28 is connected to a power source 32 via a rotary switch 30 and a key switch 31.

The rotation switch 30 of this example is opened when the engine speed exceeds a predetermined value, for example, 700 rpm.

Next, the operation of the pump 1 of this example will be explained.

At the time of starting, when the accelerator pedal is depressed, the control lever mechanism 13 is displaced to the left and rotates the tension lever 9 to the left. As a result, the control sleeve 5 is displaced in the fuel increasing direction, that is, to the right in the figure. On the other hand, the governor sleeve 14 rotates the start lever 8 to the right as the rotation speed increases;
At the time of starting, the rotational speed is low, so the urging force on the start lever 8 is small, and the amount of rotation of the start lever 8 is small. Therefore, in this state, the tension lever 8
compresses the start idle spring 18 and the start spring 19, displacing them to the left and moving the control sleeve 5 to the right to increase fuel. As a result, starting supercharging will be performed.

In this case, at the time of starting, the key switch 31 is turned on, and since the rotational speed is low, the rotation switch 30 is on, and therefore, at the time of starting, the electromagnetic device 28 is activated. As a result, the operation of the bellows mechanism 20 is restricted, and the injection amount is not reduced by the high altitude correction. Therefore, even when starting at a high altitude with low atmospheric pressure, a sufficient amount of starting supercharging can be ensured.

Thereafter, as the rotational speed increases, the biasing force of the flyweights 17 increases, causing the start lever 8 to rotate to the right against the biasing force of the tension lever 8, thereby moving the control sleeve 5 to the left. to reduce the fuel injection amount.

This ends the starting supercharging.

In this case, when the rotational speed increases and exceeds a predetermined rotational speed, in this example, 700 rpm, the rotation switch 31 is turned off and the operation of the plunger 28a of the electromagnetic device 28 is stopped.

As a result, the plunger 23 of the bellows mechanism 20
Since the restraint by the lever 29 is released, it can be freely displaced in response to changes in atmospheric pressure. As a result, high altitude correction is performed via the control arm 25.

Therefore, in the pump 1 of this example, the rotation speed increases and
High altitude correction will be performed for the first time when the engine exits the starting state. As a result, as shown in Fig. 2, in the starting supercharging region, the fuel injection amount has a single change characteristic regardless of changes in atmospheric pressure, but in the normal operating region beyond the starting time. In this case, the fuel injection amount changes depending on the atmospheric pressure. Therefore, under normal atmospheric pressure conditions, the maximum fuel injection amount is relatively large, as shown by the solid line a in Figure 2, but in low atmospheric conditions such as at high altitudes, the high altitude correction device operates, as shown by the broken line. As a result, under normal operating conditions, the generation of smoke can be effectively suppressed regardless of changes in air pressure.

Referring to FIG. 3, a fuel injection pump according to another embodiment of the present invention is shown.

In the structure of this example, the plunger 28a of the electromagnetic device 28 is
It directly engages with the bellows body 22 and compresses it. When the plunger 28a compresses the bellows 22, the bellows mechanism 20 becomes inoperable.
No altitude correction is performed. Furthermore, since the operation of the electromagnetic device 28 is the same as in the previous example, the same effects as in the previous example can be obtained.

FIG. 4 shows a fuel injection pump according to yet another embodiment of the present invention.

In the structure of this example, a cylinder device 34 includes a piston 33 that engages with the lower end of the plunger 23 of the bellows mechanism 20.
is configured. The cylinder 35 of this device is divided into two by a piston 33, and an upper pressure chamber 3
5a communicates with the hydraulic chamber 36 of the pump 1,
The lower pressure chamber 35b communicates with a return passage 37 from the hydraulic chamber 36. Therefore, the upper pressure chamber 35a
The hydraulic pressure of the hydraulic chamber 36 acts, and the lower pressure chamber a5
The oil pressure in the return passage 37 acts on this. The pressure in the hydraulic chamber 36 increases as the rotation speed increases. On the other hand, since the return passage 37 communicates with the hydraulic chamber 36 via the throttle valve 38, the hydraulic chamber 3
It is hardly affected by the pressure change in step 6 and is maintained at a substantially constant pressure.

Therefore, in the starting state where the rotation speed is low, the piston 33 is urged upward by the spring 39 disposed in the lower pressure chamber 35b, thereby forcibly compressing the plunger 23 and limiting the operation of the bellows mechanism. There is. Therefore, in this state, high altitude correction is stopped or limited. However, when the engine speed increases and the pressure in the hydraulic chamber 36 increases, the pressure in the upper pressure chamber 35a also increases, pushing the piston 33 down against the elastic force of the spring 39. Thereby, the bellows mechanism can be displaced in accordance with atmospheric pressure, and high altitude correction is performed. That is, in this example as well, since high altitude correction is not performed in the starting supercharging region where the rotational speed is low, a sufficient starting supercharging amount can be obtained regardless of changes in atmospheric pressure.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a fuel injection pump according to one embodiment of the present invention, FIG. 2 is a graph showing the relationship between engine speed and fuel injection amount, and FIG. FIG. 4 is a partial sectional view of a fuel injection pump according to yet another embodiment of the present invention. 1... Pump, 2... Drive shaft, 3... Plunger, 4... Cam disc, 5... Control sleeve, 5a.
... Pin hole, 6 ... Governor lever mechanism, 7 ... Radbin to ball, 8 ... Start lever, 9 ... Tension lever, 10... Collector lever, 10a... Full load adjustment screw, 11... Support shaft, 12... Support spring, 13... ... Control lever mechanism, 14 ... Governor sleeve, 15 ... Governor shaft, 16 ... Governor halter, 17 ... Fly weight,

Claims (1)

[Claims] Equipped with a starting supercharging device that increases the amount of fuel supplied during startup, and a fuel injection amount correction device that reduces the maximum fuel injection amount when operating at high altitudes with low atmospheric pressure than when operating at low altitudes under normal atmospheric pressure conditions. A fuel injection pump for a diesel engine, characterized in that the fuel injection pump for a diesel engine is provided with a control means for restricting or stopping the operation of the high altitude correction device in a starting supercharging region.