JP2003148286A - Heater-loaded fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heater-loaded fuel injection device capable of efficiently heating fuel with a heater and capable of stably securing the seal characteristic of a seal member. SOLUTION: A ceramic heater 50 is housed in a fuel passage 60 formed in a valve body 11. Electric power is supplied to the ceramic heater 50 through electric wiring 80. A fuel carrying passage 72 formed in a carrying pipe 70 is communicated with the upstream of the fuel passage 60 to carry the fuel to the fuel passage 60. The carrying pipe 70 is provided with a seal member 90, and the electric wiring 80 is taken out through the seal member 90.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an internal combustion engine (hereinafter,
Engine) fuel injection device.

[0002]

2. Description of the Related Art In recent years, exhaust gas regulations for vehicles have been tightened. In order to reduce harmful components contained in the exhaust gas, it is important to atomize the spray injected from the fuel injection device. As one of the measures for atomizing the fuel spray, it is known to inject heated fuel and boil the fuel under reduced pressure.
Particularly, it is effective to reduce the harmful components by boiling the fuel injected at the cold start under reduced pressure to atomize the fuel.

[0003]

As a method of heating fuel at low cost, it is considered to attach a heater to the outer periphery of the fuel injection device. However, since this method has poor heating efficiency, it is difficult to instantly raise the temperature of the fuel from the start of heating. There is also a problem that the power consumption for heating is large.

Therefore, Japanese Patent Publication No. 2000-508041 proposes a method in which a heater is housed in the fuel passage to directly heat the fuel in the fuel passage. in this way,
A seal member is provided on the member forming the fuel passage, and electric wiring for supplying electric power to the heater is taken out to the outside through the seal member. However, since the seal member is close to the heater, rapid thermal expansion and contraction are repeated following the heating and cooling of the heater. Such thermal stress deteriorates the sealing member and deteriorates its sealing characteristics. Further, when the member forming the fuel passage is made of a metal material, a costly sealing method such as glass sealing has to be adopted to take out the electric wiring.

It is an object of the present invention to provide a heater-mounted fuel injection device which has a high heating efficiency of fuel by a heater and which can secure stable sealing characteristics of a sealing member.

[0006]

According to the heater-equipped fuel injection device of the first aspect of the present invention, since the heater accommodated in the fuel passage directly heats the fuel, the fuel heating efficiency is high. Further, the electric wiring for supplying power to the heater is taken out through the seal member, but the seal member is provided in the carrier pipe forming the fuel carrier passage communicating with the upstream side of the fuel passage, so that the fuel It is separated from the heater housed in the passage and does not come into contact with the heated fuel. Therefore, the seal member is not easily affected by heat from the heater,
Stable sealing characteristics can be secured.

According to the heater-mounted fuel injection device of the second aspect of the present invention, since the seal member is made of a rubber material, the electric wiring of the heater can be inexpensively sealed.

According to the heater-equipped fuel injection device of the third aspect of the present invention, the heater is inserted into the hollow cylindrical valve member, and the fuel heated by the heater is passed through the outflow hole. It flows out of the cylinder and is guided to the injection hole. Therefore, since the fuel is heated immediately before being introduced into the injection hole, it is easy to adjust the temperature of the fuel injected from the injection hole.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a heater-mounted fuel injection device according to an embodiment of the present invention. Heater mounted fuel injection device (hereinafter, simply referred to as fuel injection device) 10
The valve body 11 has a substantially cylindrical shape, and the valve body main body 1
2, the first magnetic cylinder portion 13, the non-magnetic cylinder portion 14, and the second magnetic cylinder portion 15. The valve body 12 includes a valve member 20.
The abutting portion 21 is provided with a valve seat 12a on which the seat can be seated. The non-magnetic cylinder portion 14 includes a first magnetic cylinder portion 13 and a second magnetic cylinder portion 15.
Prevents short circuit of magnetic flux between and. First magnetic tube portion 13
The valve body main body 12 is welded to the inner wall of the fuel injection side, and the injection hole plate 16 is welded to the bottom outer wall of the valve body main body 12 located on the downstream side of the valve seat 12a. The injection hole plate 16 is formed with a plurality of injection holes 16a.

A fuel passage 60 is formed in the valve body 11. The fuel passage 60 accommodates the valve member 20, the adjusting pipe 26, the spring 27, the filter 35, the ceramic heater 50, and the like.

The valve member 20 is formed in a hollow cylindrical shape with a bottom. The valve member 20 can reciprocate in the cylinder axis direction in the fuel passage 60, and can be seated on the valve seat 12a by the bottom contact portion 21. When the contact portion 21 is seated on the valve seat 12a, the injection hole 16a is closed. On the other hand, when the contact portion 21 is separated from the valve seat 12a, the injection hole 16a is opened. A movable core 25 is welded to the opposite injection side of the valve member 20. Valve member 20
An outflow hole 22 and a steam escape hole 23 that communicate the inside and outside of the cylinder are formed in the cylinder wall of the. The outflow hole 22 is formed on the downstream side of the ceramic heater 50, and the vapor escape hole 23 is formed on the upstream side of the outflow hole 22.

The second magnetic cylinder portion 15 as a fixed core faces the movable core 25, and the adjusting pipe 26 is press-fitted into the second magnetic cylinder portion 15. Spring 2
7 has one end locked to the adjusting pipe 26,
The other end is locked to the movable core 25. The load of the spring 27 can be changed by adjusting the press-fitting amount of the adjusting pipe 26. The valve member 20 is biased toward the valve seat 12a by the biasing force of the spring 27.

The filter 35 is provided upstream of the fuel passage 60. The filter 35 is held by the collar 34 fixed to the inner wall of the second magnetic tubular portion 15. The fuel flows into the fuel passage 60 from the fuel inlet 62 at the upstream end, and the filter 35 removes foreign matters in the inflowing fuel. In the fuel passage 60, the fuel that has passed through the filter 35 has a fuel passage in the adjusting pipe 26, a fuel passage in the second magnetic tubular portion 15, a fuel passage in the valve member 20, an outflow hole 22, and an outer wall of the valve member 20. And the valve body 12 and the first magnetic cylinder 1
3, the fuel passage formed between the inner wall 3 and the valve member 20.
Is separated from the valve seat 12a, the contact portion 21 and the valve seat 12a
And is guided to the injection hole 16 a of the injection hole plate 16.

A ceramic heater 50 which is an example of a heater.
Is a heating resistor sintered with ceramics and integrally molded in a shaft shape. The ceramic heater 50 has a fuel passage 60.
Among them, the fuel is accommodated in the fuel passage in the adjusting pipe 26, the fuel passage in the second magnetic cylindrical portion 15, and the fuel passage in the valve member 20. The ceramic heater 50 extends from the downstream end of the filter 35 to the upstream side of the outflow hole 22 of the valve member 20. A pair of electrodes 51, 51
Is electrically connected to the heating resistor of the ceramic heater 50. The electrodes 51, 51 penetrate the filter 35, are held by the collar 34, and project from the fuel inlet 62.

A transfer pipe 70 is attached to the upstream side of the valve body 11. The transfer tube 70 is resin-molded into a tubular shape having a bottom. The transfer pipe 70 has a fuel transfer path 72 formed therein and transfers fuel pressurized by a high pressure pump (not shown). A fuel supply port 74 is formed integrally with the side portion 73 of the carrier pipe 70. The fuel supply port 74 has an inner hole 75 that communicates the inside and outside of the pipe. The fuel inlet 62 is fitted into the fuel supply port 74, and the fuel transfer passage 72 and the fuel passage 60 are communicated with each other through the inner hole 75. An O-ring 76 seals between the fuel supply port 74 and the fuel inlet port 62. The fuel carried by the carrier pipe 70 is introduced into the fuel passage 60 through the fuel supply port 74 and the fuel inlet 62.

An electric wire 80 extends in the fuel transfer path 72. The electrodes 51, 51 enter the fuel transfer path 72 through the fuel inlet 62 and the fuel supply port 74, and the terminal 82
Are electrically connected to the electric wiring 80. Electrode 5
1, 51 and the terminal 82 are connected by caulking, spot welding, or the like. The through hole 84 is used for the transport pipe 7.
0 through the bottom 86. One end of the electric wiring 80 is inserted into the through hole 84 and taken out of the transfer pipe 70 via the seal member 90. An O-ring made of a rubber material is used as the seal member 90.
0 is provided between the inner peripheral wall of the through hole 84 and the electric wiring 80 to seal between them. A connector 92 is integrally formed on the outer wall of the bottom portion 86. The terminal 94 is embedded in the connector 92 and electrically connected to the extraction side end of the electric wiring 80. By energizing the electric wiring 80 through the terminal 94, the electrode 5 of the ceramic heater 50
Power is supplied to 1, 51.

A resin spool 41 is mounted on the outer periphery of the valve body 11, and the coil 4 is mounted on the outer periphery of the spool 41.
0 is wound. The magnetic members 36 and 37 are coils 40
Are arranged on the outer peripheral side of the first magnetic cylinder portion 13 and the second magnetic cylinder portion 13, respectively.
It is in contact with the magnetic tube portion 15. The 1st magnetic cylinder part 13, the movable core 25, the 2nd magnetic cylinder part 15, and the magnetic members 36 and 37.
A magnetic circuit is configured by. The outer periphery of the spool 41, the coil 40, and the magnetic members 36 and 37 is covered with a resin-molded connector 45. The terminal 46 is embedded in the connector 45 and is electrically connected to the coil 40.

In the fuel injection device 10 configured as described above, when the coil 40 is de-energized, the spring 27 moves the valve member 20 downward in FIG. 1, that is, in the valve closing direction to move the valve member 20. The contact portion 21 is seated on the valve seat 12a, and the fuel injection from the injection hole 16a is blocked.

When the coil 40 is energized, the magnetic flux generated in the coil 40 flows in the magnetic circuit surrounding the coil 40, and a magnetic attraction force is generated between the second magnetic cylinder portion 15 and the movable core 25. . Then, the movable core 25 and the valve member 20 resist the urging force of the spring 27 and the second magnetic cylindrical portion 1
The abutment portion 21 is separated from the valve seat 12a by being sucked toward the side of the valve 5. As a result, the fuel that has flowed out of the valve member 20 to the outside of the cylinder through the outflow hole 22 is injected from the injection hole 16a.

When electric power is supplied to the ceramic heater 50 for a certain period of time when starting the engine, the temperature of the ceramic heater 50 instantly rises. When the coil member 40 is energized and the valve member 20 separates from the valve seat 12a while the ceramic heater 50 is being supplied with current, the fuel in the valve member 20 heated by the ceramic heater 50 that generates heat flows out from the outlet hole 22. To the outside of the cylinder and is injected from the injection hole 16a. Then, the fuel injected from the injection hole 16a is boiled under reduced pressure and atomized. In this embodiment, since the ceramic heater 50 is housed in the valve member 20 upstream of the outflow hole 22, the fuel can be heated until just before the injection. As a result, the temperature of the fuel is less likely to drop before injection, so the injection hole 1
It is easy to adjust the temperature of the fuel injected from 6a to a predetermined value.
It should be noted that when the ceramic heater 50 heats the fuel, fuel vapor that hinders the flow of the fuel may be generated. The fuel is discharged to the upstream side of the fuel passage 60.

When a certain time has passed since the engine was started, the power supply to the ceramic heater 50 is stopped to save electric energy. As a result, the ceramic heater 50 is rapidly cooled from the heat generation state. The seal member 90 that seals the electric wiring 80 is provided on the bottom portion 86 of the transfer pipe 70 that does not house the ceramic heater 50, and is separated from the ceramic heater 50 that is housed in the fuel passage 60. Further, since the seal member 90 is provided in the carrier pipe 70 connected to the upstream side of the fuel passage 60, it does not come into contact with the heated fuel. Therefore, the seal member 90 is unlikely to be affected by the ceramic heater 50. Therefore, even if an inexpensive O-ring is used as the sealing member 90, the sealing characteristics can be always secured stably.

In the above described embodiment, the seal member 9 is used.
Although an O-ring made of a rubber material is used as 0, another sealing member may be used as long as desired sealing characteristics can be realized. Although the ceramic heater 50 is used as the heater in the above embodiment, other heating means may be used as long as the fuel can be heated quickly.

Further, in the above embodiment, the seal member 90 is
The seal member 90 is provided on the side portion 73 of the carrier pipe 70, which is provided on the bottom portion 86 of the carrier pipe 70 that forms the fuel carrier path 72.
May be provided.

Further, in the above embodiment, as shown in FIG.
The ceramic heater 50 was also housed in a portion of the fuel passage 60 other than in the cylinder of the valve member 20, but, for example, as shown in a modified example in FIG. You may. When the ceramic heater 50 is housed only in the cylinder of the valve member 20, the ceramic heater 50 can be further separated from the sealing member 90, so that the stability of the sealing characteristic is improved. Furthermore, although the hollow valve member 20 is used in the above embodiment, a solid valve member may be used to house the ceramic heater in the fuel passage outside the valve member.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a heater-mounted fuel injection device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a modified example of the heater-equipped fuel injection device shown in FIG.

[Explanation of symbols]

10 Fuel injection device with heater 11 valve body 12 valve body 12a valve seat 16 nozzle plate 16a injection hole 20 valve members 21 Contact part 22 Outflow hole 50 Ceramic heater (heater) 60 fuel passage 70 Transport tube 72 Fuel transfer path 80 electrical wiring 90 Seal member (O ring)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02M 55/02 330 F02M 55/02 330B 350 350B 350G 61/10 61/10 Q

Claims (3)

[Claims] 1. A valve body, which forms a fuel passage and has a valve seat on the downstream side of the fuel passage and on the upstream side of the injection hole, and is accommodated in the fuel passage so as to be capable of reciprocating and seated on the valve seat. A valve member having an abutting portion, closing the injection hole when the abutting portion is seated on the valve seat, and opening the injection hole by moving away from the valve seat; Of these, a heater that is housed on the upstream side of the valve seat and that directly heats the fuel in the fuel passage, electric wiring that supplies power to the heater, and fuel that communicates with the upstream side of the fuel passage and that supplies fuel to the fuel passage. A fuel-injection type fuel injection device, comprising: a transfer pipe that forms a fuel transfer path for transfer; a transfer pipe that is provided with a seal member, and through which the electric wiring is taken out through the seal member. apparatus. 2. The heater mounted fuel injection device according to claim 1, wherein the seal member is made of a rubber material. 3. The valve member is formed in a hollow cylinder shape, has an outflow hole in a cylinder wall, the heater is inserted in the cylinder, and the fuel heated by the heater is passed through the outflow hole to the outside of the cylinder. 3. The heater-equipped fuel injection device according to claim 1, wherein the fuel injection device flows out into the nozzle and is guided to the injection hole.