JPH08529Y2 - Fuel injector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a fuel injection device, and more particularly to an injection amount control structure for a diesel engine in-line injection pump.

(Prior Art) As is well known, in a column injection pump used in a diesel engine, the amount of injected fuel is set as follows.

That is, the control rack equipped in the fuel adjustment mechanism in the pump is moved according to the depression of the accelerator, and the spill port (escaping hole) formed in the plunger barrel is moved to the plunger side according to the movement amount. The amount of fuel to be pumped is set by changing the communication start timing of the positioned plunger lead and adjusting the application time of the pressure generated by the movement of the plunger by this time.

Then, the fuel pumped from the injection pump reaches the needle valve opening pressure chamber in the injection nozzle, and is injected through the injection hole when the pumping pressure reaches or exceeds the valve opening pressure.

(Problems to be Solved by the Invention) In the case of the above-mentioned injection nozzle, in the case of the hole type nozzle shown in FIG. 3, a so-called suck volume (shaded line in the figure) is provided between the tip of the needle valve and the injection hole. Exists, and the fuel easily accumulates in this space, and if the fuel accumulates, the fuel may flow out at a low pressure immediately before the end of injection and drip into the combustion chamber.

Such a phenomenon is due to the fact that the suck volume described above is constant, and therefore, in the combustion gas at a low load with a small amount of fuel and a small injection pressure, as compared to a high load with a large amount of fuel and high-pressure injection. It tends to be noticeable because the proportion of unburned fuel in the

Therefore, the fuel that has flown into the combustion chamber causes incomplete combustion at the end of combustion, which increases the generation of harmful components such as hydrocarbons (HC) and particulates in the exhaust gas.

Therefore, an object of the present invention is to obtain a fuel injection device using a fuel injection pump capable of suppressing the generation of harmful components in exhaust gas in view of the problems in the above-described conventional fuel injection pump.

(Means for Solving the Problem) In order to achieve this object, the present invention is a fuel injection device equipped with a column injection pump for a diesel engine, wherein all cylinders of the control sleeve in the column injection pump are provided. In a number of control sleeves corresponding to a predetermined number in the number, a sub-control rack that is provided separately from the control rack that engages with the control pinion integrated with the sleeve and that is movable in parallel with the control rack, A transmission device that is arranged between the control pinion and the control sleeve, and sets the power transmission between them to the disconnected state when the initial position of the control rack is returned to allow power transmission from the sub-control rack. , Above sub-control rack and normal control rack A rotatable transmission lever whose ends are supported by and a pin arranged at a position forming a fulcrum for rotation of the transmission lever and movably provided in a direction parallel to the control rack; It is proposed to provide means for moving the pin to the rotation fulcrum position of the transmission lever when the accelerator pedal is released except when the engine is stopped and the exhaust brake is activated, which is connected to the pin. Is.

(Operation) According to the present invention, when the control rack returns to the initial position in conjunction with the release of the accelerator pedal depression, the transmission lever rotates about the pin as a fulcrum in the process,
Move the sub control rack in the opposite direction to the control rack. The control sleeve, which is in a state where power is not transmitted from the control rack, displaces the plunger lead on the plunger side in the fuel increasing direction by the movement of the sub control rack.

(Embodiment) Hereinafter, the details of the embodiment of the present invention will be described with reference to FIG. 1 and FIG.

FIG. 1 is a model diagram for explaining the principle of an injection pump used in a fuel injection device according to an embodiment of the present invention.

The feature of the present embodiment is that when the minimum injection amount of fuel is set, fuel is not injected in all of the cylinders, and in some of the cylinders, injection is performed in the remaining cylinders. The point is that the injection of the amount including the fuel to be performed is performed.

That is, FIG. 1 shows the case of the minimum number of combinations of the cylinders that do not perform the above-described injection and the cylinders that do the injection.

In FIG. 1, one of the cylinders 1 and 2 is provided with a control sleeve 1A, which is a normal fuel adjusting mechanism, integrally with a control pinion (not shown) so that it rotates in association with the displacement of the control rack 3. Has become. By rotating the control sleeve 1A, the position of the plunger lead formed on the inner plunger and the spill port (escape hole) on the plunger barrel side is changed to adjust the fuel amount. There is.

On the other hand, the other two of the above-mentioned cylinders are provided with a sub-control rack 4 which is parallel to the control rack 3 in addition to the control rack 3. The sub-control rack 4 is interlocked with the control rack 3 via a transmission lever 5 described later. The relationship is set.

That is, one end of the transmission lever 5 is attached to the control rack 3 and the other end thereof is attached to the sub-control rack 4, and the transmission lever 5 is rotatably supported so that its end can be displaced in a relative direction with a pin 6 described below as a fulcrum. ing.

The pin 6 is a member that is arranged at the rotation fulcrum position of the transmission lever 5 and moves in parallel with the control rack 3. When the control rack 3 returns to the initial position, the pin 6 is at the rotation fulcrum position of the transmission lever 5. Positioned.

Further, the transmission lever 5 is set so as not to rotate by a locking mechanism (not shown) when the pin 6 is not in the rotation fulcrum position.

In the structure described above, when the accelerator pedal is released and the control rack 3 returns to the initial position, the control sleeve 1A on the cylinder 1 side follows the displacement of the control rack 3 and the plunger does not inject fuel. For example, the plunger lead and the spill port (relief hole) on the side of the plunger barrel are communicated with each other so that the fuel cannot be pumped.

On the other hand, on the cylinder 2 side, the pin 6 moves to the rotation fulcrum position of the transmission lever 5 and is held at that position, and when the transmission lever 5 abuts the pin 6 according to the displacement of the control rack 3, the pin 6 serves as a fulcrum. Rotate. Therefore, the sub control rack 4 is displaced in the direction relative to the control rack 3 side of the transmission lever 5 to rotate the control sleeve 2A in the fuel increasing direction.

The above-described pin 6 is set as a rotation fulcrum position with respect to the transmission lever 5 and a movement amount on the side of the sub-control rack 4 where a displacement amount of the plunger lead including the amount of fuel required for combustion of fuel in a non-injection cylinder is obtained. It is supposed to be possible.

According to the above-described structure, it is possible to set the fuel non-injection state with some of the cylinders left, so that the amount of fuel flowing out from the suck volume can be eliminated. Therefore, it becomes possible to minimize the amount of harmful components generated in the exhaust gas due to the presence of unburned fuel at a low load. Further, in some of the cylinders described above, by supplying the fuel in an amount equal to or more than the normal minimum fuel, the proportion of unburned fuel in the amount of supplied fuel is reduced, in other words, high pressure. A stable atomized state can be obtained under the same conditions as the injection by.

The above is the principle used in this embodiment. Next, a specific structure will be described with reference to FIG.

That is, FIG. 2 is a perspective view showing an essential part of the fuel adjustment mechanism described above, and in the figure, reference numeral 10 indicates a control rack which constitutes a part of a normal fuel adjustment mechanism. Engages with a control pinion 12 provided integrally with the control sleeve 11. As described above with reference to FIG. 1, the control rack 11 has an initial position at which no injection in the cylinder can be set as the initial position to return in association with the depression of the accelerator pedal.

On the outer circumference of the control sleeve 11, an electromagnetic clutch 13, which is a rotational force transmission device, is arranged between the control sleeve 11 and the control pinion 12.

That is, in the case of the present embodiment, the electromagnetic clutch 13 controls the rotation of the control pinion 12 driven by the control rack 10 as a normal state.
The rotation transmission between the two is released when excitation is performed by energization linked to the accelerator pedal being released except when the engine is stopped or the exhaust brake is activated. It has a function.

Therefore, at the time of normal fuel adjustment, the movement of the control rack 10 is transmitted to the control pinion 12 as in this type of injection pump, so that the control sleeve
The rotation of 11 changes the communication position between the plunger lead and the spill port (escape hole) 15A on the side of the plunger barrel 15 via the collar 14A of the plunger 14.

On the other hand, in addition to the control pinion 12 described above, the control sleeve 11 has a sub-control pinion.
16 are integrally attached, and a sub control rack 17 is engaged with the sub control pinion 16.

That is, the sub control rack 17 is provided in parallel with the control rack 10, and is linked with the control rack 11 by the transmission lever 18.

That is, each end of the transmission lever 18 is supported by the control rack 11 and the sub-control rack 17, and at the time of the normal fuel adjustment described above, the same amount as that of the control rack 11 is set by the locking mechanism (not shown). Moving.

A pin 19 which is a fulcrum of rotation of the transmission lever 18 is arranged near the transmission lever 18.

That is, the pin 19 is formed integrally with the actuator 20A of the solenoid 20 positioned at a position where the sub control rack 17 is displaced in the relative direction to the control rack 11.

The solenoid 20 described above stores the pin 19 in a position where it does not collide with the transmission lever 18 by its own habit when deenergization set at this time is set when normal fuel adjustment time is set to normal time in this embodiment, and , Pin 18 is transmitted when the excitation is set when the accelerator pedal is released.
It is projected to a position where it abuts and the operating position is determined so as to serve as the fulcrum of rotation of the transmission lever 18 at this position. In the case of the present embodiment, the normal position of the solenoid 20 includes, for example, when the exhaust brake is set to set the fuel non-injection state in all cylinders and when the engine is stopped.

The rotational fulcrum position of the transmission lever 18 set by the pin 19 is, as described with reference to FIG. 1, when the control rack 11 returns to the initial position, the fuel required for combustion in the non-injection cylinder is The position is such that a movement amount on the sub-control rack 4 side corresponding to the displacement amount of the plunger lead including the amount can be set.

Since the present embodiment has the structure as described above, when the depression of the accelerator pedal is released except when the exhaust brake is operating or the engine is stopped, the electromagnetic clutch 13 and the solenoid 20 are excited. Therefore, the rotational force due to the engagement between the control rack 10 and the control pinion 12 is not transmitted to the control sleeve 11.

On the other hand, the sub-control rack 17 is displaced relative to the control rack 11 by colliding with the pin 19 located at the rotation fulcrum position while moving in the return direction in conjunction with the control rack 11.

Therefore, the control sleeve 11 is driven by the sub-control pinion 16 to rotate in the direction opposite to the direction in which the control rack 11 returns to the initial position, in other words, in the fuel increasing direction, and to rotate the plunger 14 via the collar 14B. Displace the plunger lead 14A in the fuel increase direction.

(Effect of the Invention) As described above, according to the present invention, the sub-control rack is provided separately from the control rack of the fuel adjustment mechanism, and the structure for setting the displacement with respect to the plunger lead from the sub-control rack is adopted. It is possible to inject fuel only in the smallest of the cylinders, which makes it possible to eliminate fuel dripping at the injection nozzle and prevent the generation of harmful components in exhaust gas. can do.

Furthermore, in the cylinder in which fuel is injected, a larger amount of fuel is injected than the minimum amount, so injection at a higher pressure can be obtained compared to injection using the minimum amount of fuel, thereby setting a stable atomization state. As a result, continuous combustion with good ignitability becomes possible.

[Brief description of drawings]

FIG. 1 is a model diagram for explaining the principle of a fuel injection device according to an embodiment of the present invention, FIG. 2 is a perspective view showing a structure for carrying out the principle shown in FIG. 1, and FIG. It is a partially expanded view which shows the injection part of an injection nozzle. 1,2 …… Cylinder, 3,10 …… Control rack, 4,17 ……
Sub-control rack, 5,18 …… Transmission lever, 6,19…
… Pin, 12 …… Control pinion, 13 …… Electromagnetic clutch, 16 …… Sub-control pinion, 20 …… Solenoid.

Claims (1)

[Scope of utility model registration request] 1. A fuel injection device equipped with a diesel engine in-line injection pump, the number of control sleeves corresponding to a predetermined number in the total number of cylinders among the control sleeves in the in-line injection pump, A sub-control rack that is provided separately from the control rack that engages with the control pinion integrated with this sleeve and that is movable in parallel with the control rack, and is arranged between the control pinion and the control sleeve. Power transmission between the control racks is set to a disconnected state when returning to the initial position to allow power transmission from the sub-control racks, and each end of the sub-control racks and normal control racks. With a rotatable transmission lever supported A pin that is arranged at a position that forms a fulcrum for rotation of the transmission lever and that is provided so as to be movable in a direction parallel to the control rack, and that is connected to the pin, except when the engine is stopped and the exhaust brake is activated. And a means for moving the pin to the rotation fulcrum position of the transmission lever when the depression of the accelerator pedal is released.