JP2778806B2 - Fuel injection device for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel injection device for an internal combustion engine,
In particular, the present invention relates to a type of fuel injection device called an air blast valve, in which fuel is atomized and injected together with compressed air.

[Conventional technology]

To inject fuel using compressed air, it has a nozzle port that is opened and closed by an electromagnetically controlled needle,
By providing a nozzle chamber in the compressed air passage inside it and opening the injection port of the fuel injection valve, injecting a required amount of fuel from the injection port into the compressed air in the nozzle chamber and mixing, and then opening the needle A so-called air blast valve for injecting a mixture of fuel and compressed air from a nozzle port to atomize the fuel is known from Japanese Patent Publication No. 60-501963.

FIG. 9 shows an example of the structure of a conventional air blast valve that has been put into practical use. In the same figure, 21 is a body, 22 is a needle insertion hole, 23 is a nozzle port, 24 is a spring chamber, 25 is a needle for opening and closing the nozzle port 23, 26 is a valve section, 27 is a drive section housing, 28 is a stator, and 29 is a stator. A spring retainer, 30 is a compression spring, 31 is a 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, and 40 is provided in the housing 27. A movable core insertion hole, 41 is a compressed air introduction path, 42 is a strainer, 43 is a compressed air source such as an air compressor or an air tank connected through an air blast valve of another cylinder and a common compressed air supply path 38,
46 is a nozzle chamber, 47 is a compressed air outflow passage, 48 is a stator 28
Communication holes for compressed air uniformly provided on the entire circumference of the flange portion of the above, 49 is an air passage on the upstream side thereof, 50 is a compressed air passage leading from the spring chamber 24 to the nozzle chamber 46, 51 is a fuel injection valve, and 52 is a fuel injection valve. The nozzle port opens into the nozzle chamber 46. Further, 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, 61 is a movable core 32 and a movable core inserted into the housing 27 which slidably guides the movable core 32. The gap with the hole 40 is shown.

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 to a supply passage 38, a strainer 42, a compressed air introduction passage 41, a movable core insertion hole 40, an air passage
49, solenoid chamber 39, communication hole 48, compressed air passage 50, nozzle chamber 46, compressed air outflow passage 47, needle insertion hole
Sent within 22 to charge.

When the solenoid 53 of the fuel injection valve 51 is energized, the injection port 52 is opened for a time period for connecting the control pulse, and the fuel adjusted to the predetermined pressure is injected into the nozzle chamber 46 by an amount corresponding to the time period. The injected fuel is mixed into the compressed air in the nozzle chamber 46, the compressed air outflow passage 47 connected to the nozzle chamber 46, the needle insertion hole 22, and the like to form an emulsion mixture.
Then, the solenoid 34 is energized, and the movable core 32 is
When the needle 25 is depressed magnetically, the valve portion 26 opens the nozzle port 23, and a mixture of fuel and compressed air is ejected into the fuel chamber 54 of the internal combustion engine.

[Problems to be Solved by the Invention] In the conventional air blast valve 19, a communication hole 48 provided in the movable core insertion hole 40 and the entire circumference of the stator 28 while compressed air is supplied to the nozzle chamber 46 and the like. However, since the compressed air contains liquid water that separates when the atmosphere is compressed, the water flows through the movable part such as the gap 61 between the movable core 32 and the movable core insertion hole 40 and the fixed part. Water is frozen while the engine is stopped at low temperatures and the movable core 32
In some cases, it is impossible to open the nozzle port 23 by the valve portion 26 of the needle 25, so that the fuel injected from the injection port 52 of the fuel injection valve 51
The fuel cannot accumulate in the compressed air passage and cannot accumulate in the compressed air passage. Further, the fuel enters the air blast valve (not shown) of another cylinder from the compressed air supply passage 38, and the air-fuel ratio becomes excessively rich. It has been found that normal combustion cannot be performed, and a problem of hindering the operation of the engine may occur.
As described above, it was clarified that this was due to freezing of water in the compressed air.

This problem is not only caused by the structure of the air blast valve that prevents the movable part from being locked by freezing of water in the compressed air, but also by the normal operation of the air blast valve needle 25. If it is possible to automatically detect the abnormal state in which the fuel injection is no longer performed by any means, it is considered that the operation of the fuel injection valve 51 can be stopped and a response can be made in the event of an abnormality. An object of the present invention is to find such means.

[Means for solving the problem]

In order to solve the above-described problems, the present invention provides a body having a nozzle opening at a lower portion and a driving unit housing integrally provided at an upper portion, and a nozzle attached from a side of the body to the driving unit housing. A fuel injection valve that opens an injection port in the middle of a compressed air passage reaching the mouth, a compressed air introduction path that guides compressed air to the drive unit housing from above,
A fuel injection device for an internal combustion engine having a stator, a solenoid, an electromagnetic actuator including a movable core and a movable core insertion hole, provided inside the drive unit housing to drive a needle that opens and closes the nozzle port; A first solution is to prevent a compressed air passage in the drive unit housing that connects the compressed air introduction passage and the compressed air passage from passing near a gap between the movable core and the movable core insertion hole. According to a second aspect of the present invention, an acceleration sensor is attached to the drive unit housing or a part integrated with the drive unit housing, and whether an operation state is normal is determined by an output signal of the acceleration sensor. Is detected.

(Operation)

Although the present invention provides two solutions as described in the hole of the means, the basic operation as a fuel injection device of an internal combustion engine is the same, and compressed air is supplied from above to a compressed air introduction passage. Through the drive housing, cools 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.

The injection port of the fuel injection valve is opened in the middle of the compressed air passage, and when a required amount of fuel is injected and supplied into the compressed air in the compressed air passage, the emulsion mixture is compressed to the nozzle opening. An air passage is formed. When the needle is driven by the operation of the electromagnetic actuator of the drive unit housing to open the nozzle port, the fuel-air mixture in the form of an emulsion in the compressed air passage is ejected from the nozzle port, and the fuel is atomized with the diffusion of the compressed air. You.

Although the compressed air may contain separated water, according to the first solution, the passage of the compressed air in the drive unit housing slides and guides the movable core of the electromagnetic actuator and the movable core of the electromagnetic actuator. Since it is formed so as not to pass through the gap with the movable core insertion hole, water separated from the compressed air accumulates in the gap, freezes when the engine is stopped, and locks the movable core. You.

In a normal operating state, the needle is reciprocated by the movable core of the electromagnetic actuator to open and close the nozzle port. Therefore, both ends of the reciprocating motion, that is, when the movable core collides with the stator, and when the needle collides with the nozzle port. In this case, the direction of movement of the movable core, which is a movable part, and the needle changes. This change in acceleration 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. Can be. If the signal is not detected, it is possible to determine that the needle is not operating normally and stop the fuel injection of the fuel injection valve.

〔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 denoted by the same reference numerals. A needle insertion hole 22 that extends straight along the axis A is formed in the body 21 of the air blast valve 20. A nozzle port 23 is formed at one end of the needle insertion hole 22, and a needle insertion hole is formed at the other end. The shaft 21 is communicated with a spring chamber 24 formed in the body 21 coaxially with the axis A of 22. A needle 25 having a small diameter portion 36 and a vertical spacer 37 as shown in FIG. 4 is inserted into the needle insertion hole 22 in a part of the needle insertion hole 22, and the nozzle port 23 is provided at the tip of the needle 25. Opening / closing is controlled by the formed valve section 26. In this embodiment, the nozzle port 23
Is disposed in 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 inside the lower end of the housing 27 so as to face the spring chamber 24.
A spring retainer 29 is fixed to the needle 25 located near the upper end of the spring chamber 24, and a compression spring 30 is inserted into the spring chamber 24 between the spring retainer 29 and the body 21. The needle 25 is urged upward by the spring force of the compression spring 30, and the nozzle port 23 is
Closed by 26. The needle 25 passes through the inside of the stator 28, and the rear end 31 of the needle 25 projects upward from the stator 28. The movable core 32 is always in contact with the rear end portion 31 by the spring force of the compression spring 33. This movable core 32
Is disposed in a movable core insertion hole 40 formed in the center cylindrical portion of the stator member 55 integrated with the housing 27 in the direction of the axis A so as to be slidable in the direction of the axis A. Reference numeral 59 denotes a screw stopper that supports the upper end of the compression spring 33. The urging force of the compression spring 33 in the valve opening direction is about half of the urging force of the compression spring 30 in the valve closing direction.
The nozzle port 23 is always closed due to the difference between the urging forces 0 and 33.

A solenoid chamber 39 is formed by the stator 28 and the housing 27.
A solenoid 34 is disposed around the stator 28 in the solenoid chamber 39. When the solenoid 34 is energized, the movable core 32 slides and displaces in the movable core insertion hole 40 toward the stator 28, and as a result, the needle 25
The nozzle port 23 is opened because it slides in the direction of the nozzle port 23 against the spring force of 30.

Above the housing 27, a compressed air introduction passage 41 is formed 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 air-compressed on the upstream side (not shown) by a common compressed air passage with the air introduction passage of the air blast valve of another cylinder. It communicates with a compressed air source 43 such as a machine. On the downstream side, the compressed air introduction passage 41 passes through a passage 44 provided in the upper connector member and inclined with respect to the A axis, and the movable core 32
, And communicates with a solenoid chamber 39 formed in the housing 27. As shown in FIG. 2, the flange portion of the stator 28 has a plurality of communication holes 45 biased to one portion of the entire circumference.
The communication hole 45 is formed between the solenoid chamber 39 and the spring chamber 24.
And communicate with. Therefore, the compressed air introduction passage 41 communicates with the spring chamber 24 via the inclined air passage 44, the solenoid chamber 39, and the communication hole 45, and the air passage 44, the solenoid chamber 39,
The communication hole and the spring chamber 24 are filled with compressed air. Spring room
The 24 and the nozzle chamber 46 for the fuel injection valve 51 are communicated via an air passage 50.

In the nozzle chamber 46, the injection port 52 of the fuel injection valve 51 is arranged. The fuel injection valve 51 and its injection port 52 are arranged on the axis B, and fuel is injected from the injection port 52 along the axis B at a small spread angle. As described above, the needle insertion hole 22,
Compressed air outlet passage 47, nozzle chamber 46 and compressed air passage 50
Are connected to the compressed air source 43 through the spring chamber 24 and the compressed air introduction passage 41, so that these needle insertion holes 22,
Compressed air outlet passage 47, nozzle chamber 46 and compressed air passage 50
Is filled with compressed air. Fuel is injected into the compressed air from the injection port 52 along the axis B. Therefore, the fuel injection valve 51
The fuel injected from the blast vigorously collides with the inner wall surface of the compressed air outflow passage 47, whereby the injected fuel is rapidly emulsified in the air blast valve 20.

Next, when the solenoid 34 is energized, the movable core 32 is slid and displaced toward the stator 28, and as a result, the movable core 32 moves the needle 25 toward the nozzle port 23 against the urging force of the compression spring 30. Therefore, the nozzle port 23 opens. And
Fuel atomized and well mixed with air is sprayed from the nozzle port 23 into the combustion chamber 54 of the internal combustion engine or the like.

Generally, when air is sucked from the atmosphere and compressed by a compressor, a part of water contained as steam in the air is separated from the compressed air. The reason will be described with reference to FIG. Now, at the atmospheric temperature T ₁ (for example, normal temperature) and humidity
When inhaled 100% of the air to the compressor, of FIG. 5 P ₁
Contains point water vapor. This releases heat by compressing to a predetermined air pressure in the system, when the temperature remaining at T _1, the saturated amount of water vapor the acceptable in the air becomes a value indicated by the _two-dot P, P ₁ -P ₂ Is separated from the compressed air. Since this water does not evaporate immediately even when the system is opened to the atmosphere, in the case of a conventional air blast valve as shown in FIG. 9, the water flows between the outer periphery of the movable core 32 and the movable core insertion hole 40. When the low-temperature starts, the accumulated water freezes and locks the movable core 32 when the low-temperature starts, so even if the solenoid 34 is energized, the movable core 32 and the needle 25 do not move, and the internal combustion engine starts. There was a possibility that it would be impossible.

On the other hand, in the embodiment shown in FIG. 1, the compressed air flows from the introduction passage 41 through the inclined air passage 44 to the movable core 32.
Into the solenoid chamber 39 without passing near the
The solenoid 34 is cooled by passing through an annular passage 35 between the inner surface of the solenoid 27 and the solenoid 34, passes through a communication hole 45 provided eccentrically to the stator 28 to the spring chamber 24, and passes through a passage 50 on the same side as the nozzle port. To 23. (In this case, the communication hole
When 45 is provided over the entire circumference of the stator, water flows from the lower end face of the stator 28 to the gap 60 between the opening of the stator 28 and the needle 25.
May penetrate into the outer periphery of the movable core 32 through the air. Therefore, the gap where the water may freeze and lock the movable core 32 and the needle 25 is provided so that the compressed air passage bypasses the gap, so that the compressed air and the water separated therefrom are not so. It does not pass through the gap, and water does not accumulate in the gap and freeze.

In the embodiment shown in FIG. 1, when the air blast valve 20 becomes inoperable due to some trouble, including the case where the movable core 32 is locked by freezing of water as described above, the fuel injection valve is immediately stopped. The air blast valve 20 is filled with fuel, or the fuel flows from the air blast valve 20 to the compressed air introduction passage 41.
Through the air blast valve of another cylinder.

In the example of FIG. 1, an acceleration sensor (typically a piezoelectric element) 70 is sandwiched between a connector member 58 above the air blast valve 20 and a stator member 55 together with a seal 56, and the It is fastened and fixed.
This generates a signal when the movable core 32 collides with the stator 28, that is, a signal when the nozzle port 23 is fully opened, and a signal when the needle 25 collides with the valve seat 18, that is, a signal when the nozzle port 23 is fully opened. This signal is applied to a connector 76 having four terminals 72, 73, 74, 75, for example, as shown in FIG.
It is taken out from terminals 72 and 75 and supplied to an electronic control unit (ECU) not shown. Needless to say, the remaining 2 terminals 7
Reference numerals 3 and 74 are input terminals for driving voltage of the air blast valve 20.

As shown in FIG. 7, in response to the control pulse of the air blast valve 20 (two types of pulses for commanding injection of fuel and air), the signal of the acceleration sensor 70 generated at the time of opening and closing the valve as described above is generated. While it is obtained, it determines that it is normal and turns on the green light, and when the signal of the acceleration sensor 70 is no longer detected in response to the control pulse of the air blast valve 20, it determines that it is abnormal and turns on the red light. At the same time, the control of the fuel injection valve 51 is immediately stopped. FIG. 8 shows a control flowchart executed in the ECU. The processing of each step is clear from the flowchart of FIG.

〔The invention's effect〕

By implementing the first solution of the present invention, it is possible to lock the movable core by freezing water separated from the compressed air,
The accompanying abnormal operation is prevented, and the problem of cold start in cold weather is eliminated.

In addition, if the second solution is implemented, not only in cold weather,
The operation of the needle is automatically monitored at all times.If the needle stops operating for any reason, it is possible to immediately detect the abnormal state and take measures such as activating safety measures. Can be.

[Brief description of the drawings]

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 II-II of FIG. 1, FIG. 3 is a plan view of FIG. 4 is a cross-sectional plan view taken along the line IV-IV of FIG. 1, FIG. 5 is a diagram explaining the reason for the generation of water in the compressed air, which is a subject of the present invention, and FIG. 6 is an embodiment of a connector part. FIG. 7 shows a second embodiment of the present invention.
8 is a time chart for explaining the operation of the means for solving the problem, FIG. 8 is a flowchart illustrating the operation procedure of the control device, and FIG. 9 is a vertical sectional front view showing a conventional example. 19 ... air blast valve (conventional), 20 ... air blast valve (invention), 21 ... body, 23 ... nozzle port, 24 ... spring chamber, 25 ... needle, 27 ... drive unit housing, 28 …… stator, 32 …… movable core, 34 …… solenoid, 39 …… solenoid chamber, 40 …… movable core insertion hole, 41 …… compressed air introduction path, 43 …… compressed air source, 44 …… inclined air Passage, 45: communication hole (invention), 46: nozzle chamber, 47: compressed air outflow passage, 48: communication hole (conventional), 49: air passage (conventional), 50: compressed air passage , 51 ... fuel injection valve, 52 ... nozzle, 61 ... gap, 70 ... acceleration sensor.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takahiro Kushibe 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Yuichi Takano 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation ( 56) References JP-A-60-135661 (JP, A) JP-A-3-23363 (JP, A) JP-A-1-166270 (JP, U) JP-A-2-72364 (JP, U) 60-501963 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02M 67/02 F02M 67/12 F02M 51/06 F02M 61/08 F02M 65/00 306 F02M 63/00

Claims (2)

(57) [Claims] 1. A body having a nozzle opening at a lower part and a driving part housing integrally provided at an upper part, and a compressed air passage attached to a side of the body and extending from the driving part housing to the nozzle opening. A fuel injection valve that opens an injection port in the middle of the nozzle, a compressed air introduction passage that guides compressed air to the drive unit housing from above, and a drive valve that is provided inside the drive unit housing to drive a needle that opens and closes the nozzle port. And an electromagnetic actuator comprising a movable core and a movable core insertion hole, and a passage of compressed air in the drive unit housing for communicating the compressed air introduction passage with the compressed air passage. A fuel injection device for an internal combustion engine, wherein the fuel injection device is formed so as not to pass near a gap between a movable core and the movable core insertion hole. 2. A body having a nozzle opening at a lower portion and a driving portion housing integrally provided at an upper portion, and a compressed air passage attached to a side of the body and extending from the driving portion housing to the nozzle opening. A fuel injection valve that opens an injection port in the middle of the nozzle, a compressed air introduction passage that guides compressed air to the drive unit housing from above, and a drive valve that is provided inside the drive unit housing to drive a needle that opens and closes the nozzle port. An electromagnetic actuator comprising a stator, a solenoid, a movable core, and a movable core insertion hole, and an acceleration sensor attached to the drive unit housing or a part integrated with the drive unit housing, and an operation state is determined by an output signal of the acceleration sensor. A fuel injection device for an internal combustion engine, configured to detect whether or not the engine is normal.