JPH0458062A - Fuel injection device for internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 called an air blast valve that atomizes fuel together with compressed air and injects the atomized fuel. This invention relates to a type of fuel injection device.

[Conventional technology]

In order to inject fuel using compressed air, the fuel injection valve has a nozzle port that is opened and closed by an electromagnetically controlled needle, and a nozzle chamber is provided in the compressed air passage inside the nozzle port to open the nozzle port of the fuel injection valve. After the required amount of fuel is injected from the nozzle into the compressed air in the nozzle chamber and mixed, the needle is opened to inject a mixture of fuel and compressed air from the nozzle to atomize the fuel. Blast valves are known from Japanese Patent Publication No. 60-501963.

An example of the structure of a conventional air blast valve that has been put into practical use is shown in No. 9.
As shown in the figure. In the figure, 21 is a body, 22 is a needle insertion hole, 23 is a nozzle opening, 24 is a spring chamber, and 25
26 is a needle that opens and closes the nozzle port 23; 27 is a valve portion;
28 is a stator, 29 is a spring retainer, 30 is a compression spring, 31 is the rear end of the needle 25, 32 is a movable core, 33 is a compression spring, 34 is a solenoid that drives the movable core 32, 39 is a Solenoid chamber, 4
0 is a movable core insertion hole provided in the housing 27, 41
42 is a compressed air introduction path, 43 is a compressed air source such as an air compressor or an air tank connected via a common compressed air supply path 38 with air blast valves of other cylinders, 45
47 is a nozzle chamber, 47 is a compressed air outflow passage, 48 is a compressed air communication hole provided evenly around the entire circumference of the flange portion of the stator 28, 49 is an air passage on the upstream side thereof, 50 is a spring chamber 2
4 is a compressed air passage leading to the nozzle chamber 46; 51 is a fuel injection valve; and 52 is a nozzle thereof which opens into the nozzle chamber 46. Furthermore, 53 is a solenoid, 58 is a connector member, 60 is a gap between the rear end portion 31 of the needle and the center hole of the stator 28, and 61 is a movable core 32 and the movable core insertion of the housing 27 that slidably guides it. The gaps with the holes 40 are shown respectively.

Since the conventional air blast valve 19 has a structure as shown in FIG. 9, compressed air is supplied from a compressed air source 43 through a supply path 38, a strainer 42, a compressed air introduction path 41, and a movable core insertion hole 40.
, the air passage 49, the solenoid chamber 39, the communication hole 48, and the compressed air passage 50, and are sent into the nozzle chamber 46, the compressed air outflow passage 47, and the needle insertion hole 22 to fill them.

When the solenoid 53 of the fuel injection valve 51 is energized, the nozzle 52 opens only for the time that the control pulse is applied, and injects fuel adjusted to a predetermined pressure into the nozzle chamber 46 in an amount corresponding to that time. The injected fuel flows through the nozzle chamber 46, the compressed air outflow passage 47 connected thereto, and the needle insertion hole 22.
etc., and forms an emulsion-like mixture. Then, the solenoid 34 is energized, the movable core 32 is magnetically attracted to the stator 28, and the needle 2
5, the valve portion 26 opens the nozzle port 23, and a mixture of fuel and compressed air is injected into the fuel chamber 54 of the internal combustion engine.

[Problem to be solved by the invention]

In the conventional air blast valve 19, compressed air passes through the movable core insertion hole 40 and the communication hole 48 provided around the entire circumference of the stator 28 while being supplied to the nozzle chamber 46, etc. contains liquid water that separates when compressed, and this water accumulates in the gaps between the movable and fixed parts, such as the gap 61 between the movable core 32 and the movable core insertion hole 40, causing the engine to malfunction at low temperatures. While the water is stopped, water may freeze and lock movable parts such as the movable core 32, making it impossible for the valve portion 26 of the needle 25 to open the nozzle port 23. The fuel injected from the nozzle 52 of the valve 51 cannot go out into the fuel chamber 54 and accumulates in the compressed air passage, and the fuel is further transferred from the compressed air supply passage 38 to the air blast valve (not shown) of another cylinder. It has been discovered that water in the compressed air can cause problems such as excessively enriching the air-fuel ratio, preventing normal combustion, and interfering with engine operation. It was discovered that this was caused by the freezing of the water.

Such problems can be solved by making the air blast valve have a structure that prevents the moving parts from locking due to freezing of water in the compressed air, and also by making sure that the normal operation of the air blast valve needle 25 is not limited to this cause. If it is possible to automatically detect an abnormal state in which the fuel injection valve 51 is no longer being performed by some means, it would be possible to respond by stopping the operation of the fuel injection valve 51 in the event of an abnormality. The object of the present invention is to find such a countermeasure.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a body having a nozzle opening in the lower part and integrally provided with a drive unit housing in the upper part, and a housing attached to the side of the body. a fuel injection valve that opens a jet nozzle in the middle of a compressed air passage leading from the nozzle port to the nozzle port; a compressed air introduction path that guides compressed air from above to the drive unit housing; In a fuel injection device for an internal combustion engine, the fuel injection device includes a stator provided for driving a needle to open and close, an electromagnetic actuator consisting of a trenoid, a movable core, and a movable core insertion hole. The compressed air passage in the drive unit housing that communicates the air introduction passage with the compressed air passage is detoured so as not to pass through the vicinity of the gap between the movable core and the movable core insertion hole. In a second solution, an acceleration sensor is attached to the drive unit housing or a part integrated therewith, and the output signal of the acceleration sensor is used to detect whether the operating state is normal or not. It is characterized by

[For production]

Although the present invention brings about two solutions as described in the section of the means, the basic function as a fuel injection device for an internal combustion engine is the same, and compressed air is introduced from above through a compressed air introduction path. The compressed air is introduced into the drive housing to cool the electromagnetic actuator in the drive housing, and after exiting, it is sent through a compressed air passage to a nozzle opening opening at the bottom of the body.

A nozzle of a fuel injection valve is opened in the middle of the compressed air passage, and when the required amount of fuel is injected into the compressed air in the compressed air passage, an emulsion-like mixture is compressed up to the nozzle opening. Formed in the air passage. Then, when the needle is driven by the operation of the electromagnetic actuator in the drive unit housing and the nozzle opening is opened, the emulsion-like fuel-air mixture in the compressed air passage is ejected from the nozzle opening.
The fuel is atomized as the compressed air diffuses.

Compressed air may contain separated water,
According to the first solution, the compressed air passage in the drive unit housing is formed in a detour so as not to pass through the gap between the movable core of the electromagnetic actuator and the movable core insertion hole that slides and guides it. Therefore, troubles such as water separated from the compressed air accumulating in the gap and freezing when the engine is stopped, locking the movable core, can be avoided.

In addition, under normal operating conditions, the needle is reciprocated by the movable core of the electromagnetic actuator to open and close the nozzle opening, so when the two ends of the reciprocating movement, that is, the movable core collides with the stator, and the needle collides with the nozzle opening. When doing so, the direction of movement of the movable core and needle, which are the movable parts, changes. This acceleration change is detected by an acceleration sensor attached to a part of the drive unit housing or a body integrated therewith, and it is determined whether or not the fuel supply device of the present invention is operating normally based on the presence or absence of the signal. I can do it. If the signal is not detected, it is determined that the needle is not operating normally, and fuel injection from the fuel injection valve can be stopped.

〔Example〕

FIG. 1 shows a side view of an air blast valve 20 as an embodiment of the present invention. Components that are substantially the same as those of the conventional air blast valve shown in FIG. 9 are given the same reference numerals. A needle insertion hole 22 extending straight along the axis A is formed in the body 21 of the air blast valve 20, and a nozzle opening 23 is formed at one end of the needle insertion hole 2, and a needle insertion hole 23 is formed at the other end. It communicates with a spring chamber 24 formed within the body 21 coaxially with the axis A of the insertion hole 22 . Inside the needle insertion hole 22, there is a portion 36 with a smaller diameter than the needle insertion hole 22 and a vertical spacer 3 as shown in FIG.
7 is inserted, and the opening and closing of the nozzle port 23 is controlled by a valve portion 26 formed at the tip of the needle 25. In this embodiment, the nozzle port 23 is arranged within a combustion chamber 54 of an internal combustion engine (not shown).

A drive unit housing 27 is attached to the upper end of the body 21 in which the spring chamber 24 is formed, and a stator 28 is fixed within the lower end of the housing 27, facing the spring chamber 24. Needle 2 located near the upper end of spring chamber 24
A spring retainer 29 is fixed to the spring retainer 5 , and a compression spring 30 is inserted into the spring chamber 24 between the spring retainer 29 and the body 21 . The spring force of the compression spring 30 urges the needle 25 upward, and the nozzle opening 23 is normally closed by the valve portion 26 of the needle 25. The needle 25 passes through the stator 28, and the rear end 31 of the needle 25 projects upwardly from the stator 28. A movable core 32 is constantly brought into contact with this rear end portion 31 by the spring force of a compression spring 33. This movable core 3
2 is a stator member 55 integrated with the housing 27;
The movable core insertion hole 40 is formed in the central cylindrical part in the six axial directions, and is slidably displaceable in the six axial directions. Note that 59 is a screw frame that supports the upper end of the compression spring 33. The biasing force in the valve opening direction by the compression spring 33 is about half the biasing force in the valve closing direction by the compression spring 30, and the nozzle port 23 is always closed due to the difference in the biasing forces of these compression springs 30 and 33. becomes.

A solenoid chamber 39 is formed by the stator 28 and the housing 27, and a solenoid 34 is disposed around the stator 28 within this solenoid chamber 39. When this solenoid 34 is energized, the movable core 32 slides inside the movable core insertion hole 40 toward the stator 28 , and as a result, the needle 25 resists the spring force of the compression spring 30 and moves toward the nozzle opening 2 .
Since the nozzle opening 23 is slidably displaced in the direction 3, the nozzle port 23 opens.

A compressed air introduction path 41 is formed above the housing 27 on an extension of the axis A of the needle insertion hole 22 .

A strainer 42 is provided in the middle of the compressed air introduction passage 41, and the compressed air introduction passage 41 is compressed at an upstream side (not shown) by a compressed air passage common to the air introduction passages of the air blast valves of other cylinders. Compressed air source 43 for machines, etc.
is connected to. On the downstream side, the compressed air introduction path 41 passes through a passage 44 provided in the upper connector member and inclined with the A axis, and enters the solenoid chamber 39 formed in the housing 27 without passing near the movable core 32. It will be communicated to. As shown in FIG. 2, several communication holes 45 are formed in the flange portion of the stator 28 at one portion of the entire circumference, and the communication holes 45 communicate the solenoid chamber 39 and the spring chamber 24. Therefore, the compressed air introduction path 41 is connected to the inclined air passage 4.
4, communicates with the spring chamber 24 via the solenoid chamber 39 and the communication hole 45, and these air passages 44 and the solenoid chamber 3
9. The communication hole and the spring chamber 24 are filled with compressed air.

The spring chamber 24 and the nozzle chamber 46 for the fuel injection valve 51 are communicated via an air passage 50 .

A nozzle 52 of a fuel injection valve 51 is arranged within the nozzle chamber 46 . The fuel injection valve 51 and its nozzle 52 are arranged on the axis B, and fuel is injected from the nozzle 52 along the axis at a small spread angle. As mentioned above, the needle insertion hole 22, the compressed air outflow passage 47, the nozzle chamber 46, and the compressed air passage 50 are communicated with the compressed air source 43 via the spring chamber 24 and the compressed air introduction passage 41. The needle insertion hole 22, the compressed air outflow passage 47, the nozzle chamber 46, and the compressed air passage 50 are filled with compressed air. Fuel is injected into this compressed air from the nozzle 52 along the axis B. Therefore, the fuel injected from the fuel injection valve 51 collides with the inner wall surface of the compressed air outflow passage 47,
As a result, the injected fuel is rapidly emulsified within the air blast valve 20.

Next, when the solenoid 34 is energized, the movable core 32 is slidably displaced toward the stator 28 , and as a result, the movable core 3
2 causes the needle 25 to move in the direction of the nozzle port 23 against the biasing force of the compression spring 30, so that the nozzle port 23 opens. Then, the atomized fuel spray mixed well with air is ejected from the nozzle port 23 into the combustion chamber 54 of the internal combustion engine.

Generally, when air is drawn from the atmosphere and compressed by a compressor, some of the water contained in the atmosphere as water vapor is separated from the compressed air. The reason for this will be explained with reference to FIG. Now, if air with an atmospheric temperature T1 (for example, room temperature) and a humidity of 100% is sucked into the compressor, it contains water vapor at point P+ in FIG. If this air is compressed to the predetermined air pressure in this system and the heat is radiated, and the temperature remains at T1, the amount of saturated water vapor allowed in this air will be the value shown by 22 points, which corresponds to P, -P2. Water will separate from the compressed air. This water does not evaporate immediately even if the system is opened to the atmosphere, so in the case of a conventional air blast valve as shown in FIG. The water that collects in the compressed air passage formed between them freezes and locks the movable core 32 when the temperature starts, so even if the solenoid 34 is energized, the movable core 32 and needle 25 do not move, and the internal combustion engine starts. There was a risk that it would become impossible.

On the other hand, in the embodiment shown in FIG. 1, compressed air enters the solenoid chamber 39 from the introduction path 41 through the inclined air passage 44 without passing near the movable core 32, and enters the solenoid chamber 39 between the inner surface of the housing 27 and the solenoid. annular passage 3 between 34 and
5 to cool the solenoid 34, exit to the spring chamber 24 through a communication hole 45 provided at an angle in the stator 28, and head to the nozzle port 23 via a passage 50 on the same side. (In this case, if the communication hole 45 is provided all around the stator, water may enter the outer periphery of the movable core 32 from the lower end surface of the stator 28 through the gap 60 between the opening of the stator 28 and the needle 25. ) Therefore, the compressed air passage bypasses any gaps where water could freeze and lock the movable core 32 or the needle 25, so that the compressed air and water separated therefrom do not It does not pass through any gaps, and water will not accumulate in the gaps and freeze.

The embodiment shown in FIG. 1 immediately stops the fuel injection valve when the air blast valve 20 becomes inoperable due to some kind of malfunction, including when the movable core 32 is locked due to water freezing as described above. However, it is configured to prevent fuel from filling up in the air blast valve 20 or from overflowing from the air blast valve 20 through the compressed air introduction path 41 to the air blast valves of other cylinders. .

In the example shown in FIG. 1, an acceleration sensor (typically made of a piezoelectric element) 70 is sandwiched between the connector member 58 on the upper part of the air blast valve 20 and the stator member 55 together with the seal 56, and the acceleration sensor 70 is inserted into the housing 27. It is tightened and fixed. This generates a signal when the movable core 32 collides with the stator 28, that is, when the nozzle port 23 is fully opened, and a signal when the needle 25 collides with the valve seat 18, that is, when the nozzle port 23 is fully closed. . This signal is transmitted, for example, to four terminals 72, 73 . . . as shown in FIG.
Two terminals 72 and 75 of connector 76 with 74.75
It is taken out and supplied to an electronic control unit (ECII), not shown. Needless to say, the remaining two terminals 73.74
is an input terminal for the driving voltage of the air blast valve 20.

As shown in FIG. 7, in response to the control pulses of the air blast valve 20 (two types of pulses that command injection of fuel and air), the signal of the acceleration sensor 70 generated when the valve is opened and closed as described above is While the signal is detected, it is determined to be normal and the green light is turned on, and when the signal from the acceleration sensor 70 is no longer detected in response to the control pulse of the air blast valve 20, it is determined to be abnormal and the red light is turned on. At the same time, the fuel injection valve 51 is immediately
control is discontinued. FIG. 8 shows a control flowchart executed in the ECU. Since the processing of each step is clear from the flowchart of FIG. 8, the explanation will be omitted.

〔Effect of the invention〕

By implementing the first solution of the present invention, locking of the movable core due to freezing of water separated from compressed air and associated abnormal operation are prevented, and the problem of cold starting in cold weather is resolved. do.

In addition, if the second solution is implemented, the operation of the needle will be automatically monitored at all times, not only in cold weather, and if the needle stops working for some reason, an abnormal state will be immediately detected. It is possible to take countermeasures such as activating safety measures.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view showing an embodiment of the present invention, FIG. 2 is a cross-sectional plan view taken along the line ■-■ in FIG. 1, FIG. Figure 4 shows the IV-T in Figure 1.
A cross-sectional plan view along the V line, FIG. 5 is a line diagram explaining the reason why water is generated in compressed air, which is a problem of the present invention, FIG. 6 is a side view showing an example of the connector part, and FIG. FIG. 8 is a time chart for explaining the operation of the second solving means of the present invention, FIG. 8 is a flowchart similarly illustrating the procedure of operation of the control device, and FIG. 9 is a longitudinal sectional front view showing a conventional example. 19... Air blast valve (conventional), 20... Air blast valve (present invention), 21... Body, 23... Nozzle port, 24... Spring chamber, 25... Needle nozzle 27. ... Drive unit housing, 28... Stator, 32... Movable core, 3
4... Solenoid, 39... Solenoid chamber, 40...
...Movable core insertion hole, 41...Compressed air introduction path, 4
3... Compressed air source, 45... Communication hole (present invention), 47... Compressed air outflow passage, 49... Air passage (conventional), 51... Fuel injection valve, 61... Gap, 44... Inclined air passage, 46... Nozzle chamber, 48... Communication hole (conventional), 50... Compressed air passage, 52... Nozzle port, 70... Acceleration sensor.

Claims (2)

[Claims] 1. A body having a nozzle opening in the lower part and a drive unit housing integrally provided in the upper part, and a nozzle attached to the side of the body and having a nozzle in the middle of a compressed air passage leading from the drive unit housing to the nozzle opening. A fuel injection valve that opens, a compressed air introduction path that guides compressed air from above to the drive unit housing, and a stator and a solenoid that are provided inside the drive unit housing to drive a needle that opens and closes the nozzle port. , an electromagnetic actuator including a movable core and a movable core insertion hole, and a compressed air passage in the drive unit housing that communicates the compressed air introduction passage with the compressed air passage; A fuel injection device for an internal combustion engine, characterized in that the fuel injection device is formed in a detour so as not to pass through the vicinity of a gap with a core insertion hole. 2. A body having a nozzle opening in the lower part and a drive unit housing integrally provided in the upper part, and a nozzle attached to the side of the body and having a nozzle in the middle of a compressed air passage leading from the drive unit housing to the nozzle opening. A fuel injection valve that opens, a compressed air introduction path that guides compressed air from above to the drive unit housing, and a stator and a solenoid that are provided inside the drive unit housing to drive a needle that opens and closes the nozzle port. , an electromagnetic actuator consisting of a movable core and a movable core insertion hole, and an acceleration sensor attached to the drive unit housing or a part integrated therewith, and whether the operating state is normal or not based on the output signal of the acceleration sensor. A fuel injection device for an internal combustion engine, characterized in that it is configured to detect.