JP2001090634A - Injection valve for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection valve of a pressure accumulating fuel injection device capable of reducing an initial injection rate, having a steep injection characteristic at the end of injection and capable of improving efficiency of the whole system. SOLUTION: A valve chest 3 is arranged between a nozzle chamber 42 on the outer periphery of a nozzle needle 4 for opening/closing a nozzle port 46 on the tip o a casing 41 and fuel supply passages 15, 23 communicated with a common rail. The valve chest 3 is partitioned into a high pressure chamber 32 connected with the fuel supply passages 15, 23, a control chamber 31 communicated with the nozzle chamber 42 and a low pressaure chamber 33 connected with fuel return passages 16, 17, and a tip part 21 having first/second valve parts of a control valve 2 is positioned in the control chamber 31. At injection starting time, the first valve part is opened, the control chamber 31 communicates with the high pressure chamber 32, so that high pressure fuel is supplied to the nozzle chamber 42, as initial injection rate reduces, the second valve part is closed, and since a part between the high pressure chamber and the low pressure chamber 33 is closed, a leak quantity reduces. At injection end time, the first valve part is closed, the second valve part is opened, and since high pressure fuel quickly flows out to the low pressure chamber 33, the end of injection becomes steep.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection valve used in a pressure-accumulation type fuel injection device for accumulating high-pressure fuel in a common rail (accumulation chamber) and injecting the accumulated high-pressure fuel into an internal combustion engine.

[0002]

2. Description of the Related Art One of the systems for injecting fuel into a diesel engine is a pressure-accumulation type fuel injection device, which can freely control the injection timing and injection amount, and is known to be effective in improving the exhaust gas value. ing. As described in Japanese Patent Application Laid-Open No. H10-153155, the pressure-accumulation type fuel injection device includes a common rail for high-pressure fuel common to each cylinder, and a high-pressure pump for pumping high-pressure fuel to the common rail. The fuel is injected and supplied to each cylinder at a predetermined timing. JP-A-10-153155 discloses a nozzle needle that opens and closes an injection hole, a control piston that receives fuel pressure in a pressure control chamber and urges the nozzle needle in a valve closing direction, a pressure control chamber and a low-pressure fuel chamber. An injection valve having an electromagnetic valve that shuts off communication between the control valve and the nozzle needle is opened by opening the electromagnetic valve to lower the pressure control chamber, thereby injecting fuel. is there.

However, in the above configuration, since high-pressure fuel leaks from the clearance between the sliding portions of the control piston and the nozzle needle, it is necessary to increase the pumping amount of the high-pressure pump to make up for the decrease due to the leak, and to improve the efficiency of the entire system. There was a problem that was worsening. On the other hand, for example, when the control piston is abolished as in the injection valve described in Japanese Patent Application Laid-Open No. 9-9086, the leak amount can be reduced. However, with this injector,
A throttle is provided at the inlet of the nozzle chamber, and the hydraulic pressure obtained by generating a pressure difference between the upper and lower sides of the nozzle needle and the spring force of the nozzle needle are used as the valve closing force at the end of injection. Due to the pressure loss, there is a problem that the actual injection pressure during the injection decreases.

On the other hand, Japanese Patent Publication No. Hei 9-510525 discloses an injection valve which controls injection by adjusting the pressure in a pressure control chamber with a double seated valve.
FIG. 7 shows this configuration.
01 and a double seated valve 2
And a pressure control chamber 204 for accommodating the passages 20 in the nozzle chamber 202 and the pressure control chamber 204, respectively.
The high-pressure fuel is supplied from the fuel supply unit 207 via 5, 206. Further, the pressure control chamber 204
Communicates with the fuel return portion 209 via the passage 208 and communicates with the spring chamber 211 via the passage 210. In the upper and lower surfaces of the pressure control chamber 204, the passage 20 is provided.
6, 208, tapered valve seats 212, 213
Are formed, and two tapered valve portions provided on the outer peripheral portion of the double seat valve 203 close the valve seats 210 and 211 according to the switching position.

In the above configuration, the double seat valve 203 is driven by the solenoid 214 and the lower valve seat 213 is provided.
When it moves away from the upper side, the fuel in the spring chamber 211 flows out to the fuel return section 209. Thereby, the nozzle needle 201 rises and high-pressure fuel is injected from the injection hole 215. However, in order to realize this configuration, the casing 216 constituting the pressure control chamber 204 is provided between the two valve seats 212 and 213 by the two casings 216 a and 216.
6b. In this case, in order to ensure the sealing performance of the abutting surfaces of the casings 216a and 216b, it is necessary to ensure the coaxiality of the sliding portion of the double seated valve 203 and the lower valve seat 213 in μm units. However, it is impossible to secure coaxiality in a unit of μm by ordinary fitting or positioning using a knock pin, and it is not possible to secure sealing performance. Therefore, the pressure in the pressure control chamber 204 does not rise sufficiently at the end of the injection, so that the cut-off of the injection deteriorates.

[0006] These conventional injection valves all have a structure in which fuel is injected by opening the nozzle needle by lowering the pressure in a pressure control chamber (back pressure chamber of the nozzle needle). In this configuration, since the nozzle chamber is always at a high pressure, the initial injection rate is high, and
There was a problem that the amount of x generation was large.

In addition, as in German Patent No. 2322214A, there is a configuration in which the nozzle needle is opened by increasing the pressure in the nozzle chamber without providing a back pressure chamber for the nozzle needle. In this configuration, a high-pressure fuel is supplied from the high-pressure passage to the nozzle chamber only at the time of injection by a servo valve that is hydraulically driven by an electromagnetic valve, and the initial injection rate is reduced. However, since the supply path of the high-pressure fuel communicates with the relief passage at the atmospheric pressure during the injection, the amount of pressure supplied by the high-pressure pump is increased, and there is a problem that the efficiency of the entire system is deteriorated.

[0008]

Therefore, in the present invention,
By simultaneously realizing the characteristics of a low initial injection rate and a sharp end of injection (good injection cut-off), the advantages of high-pressure injection can be exhibited effectively, and a pressure-accumulation system that can increase the efficiency of the entire system An object of the present invention is to provide an injection valve of a fuel injection device.

[0009]

A first aspect of the present invention is an injection valve for injecting high pressure fuel stored in a common rail into an internal combustion engine, wherein the injection valve slides in a cylindrical casing in an axial direction. A nozzle needle that opens and closes the injection hole at the tip of the casing, a nozzle chamber that is provided on the outer periphery of the nozzle needle in communication with the injection hole, and opens the nozzle needle with the pressure of high-pressure fuel supplied from a common rail; A valve chamber provided between a fuel supply passage communicating with a common rail and the nozzle chamber; a control valve disposed in the valve chamber to control inflow and outflow of high-pressure fuel to and from the nozzle chamber; and the control valve. Is provided. A fuel return passage for discharging high-pressure fuel in the nozzle chamber during non-injection is connected to the valve chamber, and the control valve opens the fuel supply passage during fuel injection to guide high-pressure fuel to the nozzle chamber. Preventing fuel from flowing into the fuel return passage, opening the fuel return passage during non-injection to guide high-pressure fuel in the nozzle chamber to the fuel return passage, and preventing fuel from flowing from the fuel supply passage. Formed to prevent.

According to the above configuration, the inflow of fuel from the fuel supply passage during non-injection is prevented, and high-pressure fuel is supplied to the nozzle chamber only during injection. it can. In addition, since fuel is prevented from flowing into the fuel return passage during fuel injection, there is no leakage of fuel during injection, and the efficiency of the entire system is good. Further, at the end of the injection, the fuel return passage is opened, the fuel is instantaneously discharged to the fuel return passage, and the pressure in the nozzle chamber can be reduced.

According to the second aspect of the invention, the valve chamber is divided into a high-pressure chamber connected to the fuel supply passage, a control chamber connected to the nozzle chamber, and a low-pressure chamber connected to the fuel return passage. A first valve unit for opening and closing the control valve between the control chamber and the high-pressure chamber and the low-pressure chamber, and a second valve unit.
The first and second valve portions are formed such that when one of the first and second valve portions is opened, the other is closed. And
At the start of injection, the first valve portion is opened, the second valve portion is closed, and high-pressure fuel is supplied from the fuel supply passage to the nozzle chamber via the high-pressure chamber and the valve chamber. At the end of the injection, the second valve portion is opened, the first valve portion is closed, and the high-pressure fuel in the nozzle chamber is discharged to the fuel return passage via the valve chamber and the low-pressure chamber.

[0012] According to the above configuration, until the start of injection, the first
Since the valve section is not opened, the pressure increase in the nozzle chamber is moderate and the initial injection rate can be reduced. Also, during injection,
Since the second valve portion is closed, fuel does not flow out to the fuel return passage side, and the efficiency of the entire system is good. Then, at the end of the injection, the second valve portion is opened, the fuel is quickly discharged to the fuel return passage, and the nozzle needle can be closed, so that the injection end is sharp.

According to the third aspect of the present invention, the diameter d1 of the sliding portion of the control valve is determined by the seat diameter d2 when the first valve portion is seated and the seat diameter d3 when the second valve portion is seated. The diameter is almost the same. Thus, the pressure of the fuel acting on the control valve is balanced, and the required suction force of the solenoid serving as the driving unit can be suppressed low, so that the size of the solenoid can be reduced.

According to a fourth aspect of the present invention, the high-pressure chamber and the low-pressure chamber are coaxially arranged on an extension of a slide hole in which the control valve is slidably arranged, with the control chamber interposed therebetween. Then, a tip portion of the control valve is disposed in the control chamber, and the first valve portion is formed on the high pressure chamber side of the tip portion, and the second valve portion is formed on the low pressure chamber side. Specifically, when the high-pressure chamber and the low-pressure chamber are arranged with the control chamber interposed therebetween and the first and second valve portions are formed at the tip of the control valve, the configuration can be made compact.

According to a fifth aspect of the present invention, the second valve portion is formed by extending the end face of the tip portion on the side of the low-pressure chamber into a cylindrical shape.
A second cylindrical member is formed at the opening edge of the low-pressure chamber having a smaller diameter.
Was brought into contact with the valve to close it. The second
By using a tubular pipe seat valve as the valve portion, the sliding portion and the second valve portion can be sealed without requiring precise coaxiality, and the sealing property can be secured with a simple configuration.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is an overall configuration diagram of an accumulator type fuel injection device including the fuel injection valve 1 of the present invention.
01 is provided with a common rail 102 as a pressure accumulation chamber provided in common for each cylinder. A plurality of fuel injection valves 1 provided for each cylinder are connected to the common rail 102, and high-pressure fuel stored in the common rail 102 is injected from each fuel injection valve 1 to a corresponding cylinder. The driving of the fuel injection valve 1 is controlled by a signal from an electronic control unit (ECU) 103 which is a control unit.

The common rail 102 has a fuel tank 10
7 is connected to a high-pressure supply pump 104 that pressurizes low-pressure fuel sucked through a feed pump 106 to a high pressure. The ECU 103 controls the fuel injection valve 1 based on a signal from a pressure sensor 108 or the like provided on the common rail 102.
Pressure control valve 1 of the high-pressure supply pump 104 so that the injection pressure of the high-pressure supply pump 104 becomes a predetermined value determined in advance in accordance with the load and the number of revolutions.
05 is driven to adjust the amount of pressure supplied from the high-pressure supply pump 104. As a result, the high-pressure fuel pumped from the high-pressure supply pump 104 into the common rail 102 is accumulated at a predetermined pressure corresponding to the fuel injection pressure. Excess fuel is returned to the fuel tank 107 via the low-pressure channel 109.

FIG. 1 shows the overall configuration of a fuel injection valve 1 according to the present invention. In FIG. 1, a fuel injection valve 1 has upper and lower casings 11 and 12 in which a control valve 2 is accommodated and a valve chamber 3 is formed, and a nozzle casing 41 which is disposed below and accommodates a nozzle needle 4. . The lower casing 12 and the nozzle casing 41 are fixed by screwing the cylindrical member 13 holding the outer periphery to the lower end of the upper casing 11. At the upper end of the upper casing 11, a cylindrical solenoid casing 51 that accommodates a solenoid 5 serving as a drive unit for driving the control valve 2 is screwed. Further, in the cylindrical portion 14 protruding to the side of the upper casing 11, the above-described FIG.
A fuel supply passage 15 communicating with the common rail 102 is provided.

In the upper casing 11, the control valve 2 is slidably disposed in a sliding hole 22 formed in the axial direction (vertical direction). The distal end 21 (lower end) of the control valve 2 is located in a control chamber 31 having a larger diameter than the sliding hole 22 formed in the lower end of the upper casing 11, and the control chamber 31 is located below the lower casing. A lower-pressure chamber 33 having a smaller diameter is formed coaxially at the upper end of 12. Above the control chamber 31, a high-pressure chamber 32 is formed between the control valve 2 and the inner wall of the slide hole 22 with the diameter of the control valve 2 connected to the distal end 21 being slightly smaller than the diameter of the slide part. The high-pressure chamber 32 has a fuel supply passage 23 connected to the fuel supply passage 15.
The low-pressure chamber 33 is connected to the upper and lower casings 11, 1 and
It communicates with fuel return passages 16 and 17 provided in the inside 2.

The control chamber 31, the high-pressure chamber 32 and the low-pressure chamber 33 constitute a valve chamber 3 communicating with each other. The control valve 2 controls communication and shutoff between the control chamber 31 and the high-pressure chamber 32 and the low-pressure chamber 33, and details thereof will be described later. The fuel return passages 16 and 17 are provided in a spring chamber 61 in which a spring 6 for urging the control valve 2 upward is disposed, a space in a push rod 52 fixed to an upper end of the control valve 2, and an upper end of the solenoid casing 51. It communicates with the outside which becomes atmospheric pressure through the passage 55 of the section.

The nozzle needle 4 is connected to the lower casing 12
Is slidably disposed in a vertical direction in a cylindrical nozzle casing 41 disposed below a circular sealing member 62. A nozzle chamber 42 is formed around an intermediate portion of the nozzle needle 4, and is always in communication with the control chamber 31 via a passage 43 extending vertically in the nozzle casing 41 and the lower casing 12. The nozzle needle 4 is urged in the valve closing direction (downward) by a spring 45 in a spring chamber 44 provided above the nozzle needle 4 to close the injection hole 46 at the lower end of the nozzle casing 41. Also,
The nozzle needle 4 has a slightly smaller diameter in the lower half and forms a gap 47 with the inner wall of the nozzle casing 41, while its shoulder 48 is located in the nozzle chamber 42. Thus, when the pressure of the high-pressure fuel introduced into the nozzle chamber 42 exceeds the urging force of the spring 45, the nozzle needle 4 starts to rise, and the high-pressure fuel in the nozzle chamber 42 is injected from the injection hole 46 through the gap 47. Is done. The spring chamber 44 communicates with the upper low-pressure chamber 33 through a communication hole 49.

The solenoid valve 51 includes a control valve 2
A push rod 52 fixed to the upper end of the cylinder extends through the hollow portion of the cylindrical solenoid 5, and an armature 53 fixed to the outer periphery of the upper end is fixed and faces the solenoid 5. In the illustrated state in which the coil 54 of the solenoid 5 is not energized, the control valve 2 is urged upward by the spring 6 in the spring chamber 61 below the solenoid 5, and when the coil 54 of the solenoid 5 is energized, the armature 53 Is sucked and the push rod 5 integrated with this
2 and the control valve 2 move downward (see FIG. 3).

As shown in FIG. 4, the distal end 21 of the control valve 2 located in the control chamber 31 has an upper end side (high pressure chamber 32).
Side) forms a first valve portion 2a having a tapered shape, and a lower end portion extends in a cylindrical shape at an outer peripheral portion to form a second valve portion 2b having a pipe seat shape. The lower end opening edge of the high-pressure chamber 32 opposed to the first valve portion 2a is formed with a tapered first seat surface 34 that is inclined slightly more gradually than the first valve portion 2a. The opening edge of the upper end of the low-pressure chamber 33 opposed to the valve portion 2b is a planar second seat surface 35. As described above, when the second valve portion 2b is formed in a pipe sheet shape, and is brought into contact with the upper end opening edge of the low-pressure chamber 33 having a smaller diameter than this, the second valve portion 2b and the second seat surface are closed. The coaxiality of 35 is not strictly required, and the divided upper and lower casings 11 and 12 can secure sealing performance. At this time, to ensure the sealing performance,
As shown in the drawing, it is preferable that the inner diameter of the second valve portion 2b is formed to be larger than the diameter of the low-pressure chamber 33.

Further, with respect to the diameter d1 of the sliding portion of the control valve 2,
The seat diameter d2 when the first valve portion 2a is seated and the seat diameter d3 when the second valve portion 2b is seated are preferably substantially the same. As a result, the pressure of the fuel acting on the control valve 2 is balanced, and the required suction force of the solenoid 5 can be kept low, which is effective for downsizing the solenoid 5 and further downsizing the entire injection valve.

Next, the operation of the injection valve having the above configuration will be described.
In the normal state in which the coil 54 of the solenoid 5 is not energized (FIG. 1)
), The spring 6 in the spring chamber 61
As a result, the control valve 2 is urged upward, the first valve portion 2a is seated on the first seat surface 34, and the high-pressure chamber 32 and the control chamber 3
1 and the second valve portion 2b is opened to open the control room 3
1 communicates with the low-pressure chamber 33. At this time, the nozzle chamber 42
Communicates with the atmospheric pressure fuel return passage through the control chamber 31 and the low pressure chamber 33, and the nozzle needle 4
Is closed.

Next, when the coil 54 is energized, the armature 53 overcomes the urging force of the spring 6 and is attracted.
The push rod 52 and the control valve 2 integrated therewith move downward. As a result, the second valve portion 2b sits on the second seat surface 35 and closes, and shuts off the space between the control chamber 31 and the low-pressure chamber 33. At the same time, the first valve portion 2a opens, and the high-pressure chamber 32 and the control chamber 31 communicate with each other, and the fuel supply passage 15,
The high-pressure fuel supplied from 23 is supplied to the high-pressure chamber 32 and the control chamber 3
1. It is supplied to the nozzle chamber 42 through the passage 43. Then, the pressure in the nozzle chamber 42 increases, the nozzle needle 4 opens, and fuel is injected from the injection hole 46.

When the energization of the coil 54 is released, the control valve 2 rises due to the urging force of the spring 6 and the first valve 2
a is seated on the first seat surface 34 to shut off the space between the control chamber 31 and the high-pressure chamber 32. At the same time, the second valve portion 2b opens, the control chamber 31 communicates with the low pressure chamber 33, and the nozzle chamber 42
The fuel inside is discharged from the atmospheric pressure fuel return passages 16 and 17 through the passage 43, the control chamber 31, and the low pressure chamber 33. As a result, the pressure in the nozzle chamber 42 decreases, the nozzle needle 4 closes, and the fuel injection ends.

FIG. 5 shows a time chart during the operation of the injection valve of the present invention (solid line in the figure). The top row of the figure shows the coil 54
When the coil 54 is energized (drive signal ON), the second valve portion 2b of the control valve 2 closes, the first valve portion 2a opens, and the high pressure is applied as described above. Fuel flows into the nozzle chamber 42 and its pressure increases. When the pressure in the nozzle chamber 42 reaches the valve opening pressure, the nozzle needle 4 starts lifting, and injection is performed. At the start of the injection, in the configuration of the present invention, since the high pressure chamber 32 and the control chamber 31 are shut off, the high pressure fuel flowing in to pressurize the control chamber 31, the passage 43, and the nozzle chamber 42 is consumed, The initial rise of the injection rate is based on the conventional injection valve in which the nozzle chamber indicated by the dotted line in the figure is always at a high pressure (the configuration of FIG. 7 described above, and the operation is indicated by the dotted line).
And the NOx generation at the beginning of the injection can be suppressed.

When the energization of the coil 54 is released (drive signal OFF), the first valve portion 2a of the control valve 2 closes, and the second
, The high pressure fuel flows out of the nozzle chamber 42 to the atmospheric pressure as described above. Accordingly, when the pressure in the nozzle chamber 42 suddenly decreases and the pressure in the nozzle chamber 42 reaches the valve closing pressure, the nozzle needle 4 is fully closed, and the injection ends. At the end of injection, in the configuration of the present invention, the high-pressure fuel in the nozzle chamber 42 is released to the atmospheric pressure, so that the pressure in the nozzle chamber 42 is quickly reduced, and the injection end is sharper than in the conventional injection valve. .

As described above, according to the present invention, an injection valve having a low initial injection rate, a sharp end of injection, and excellent injection performance can be realized. Further, since the second valve portion 2b of the control valve 2 is formed in a pipe sheet shape that does not require precise coaxiality,
Even if the casing is divided between the control chamber 31 and the low-pressure chamber 33 therebelow, the sealing performance between the second valve portion 2b and the second seat surface 35 on which the second valve portion 2b is seated can be ensured. Further, in the present embodiment, the members forming the passage 43 through which the high-pressure fuel flows toward the nozzle chamber 42, namely, the upper and lower casings 11, 12, the sealing surfaces 71, 72, 73 of the nozzle casing 41 and the sealing member 42 (FIG. (Indicated by an arrow in FIG. 3) is exposed to high pressure only during the injection period. That is, since the pressure resistance of the nozzle chamber 42 and the passage 43 is not required as in the conventional configuration in which the pressure is always high, the sealing surface 7 is not required.
The processing of 1, 72, 73 can be simplified.

The amount of leakage from the injection valve includes two types: leakage from a clearance of a sliding portion such as a control valve, a control piston, and a nozzle needle, and leakage due to operation of a control valve for controlling injection. In the present invention, the path where the leak occurs in the present invention is only the sliding portion of the control valve 2, and the leak from the sliding portion of the nozzle needle 4 is very short time (up to about 1.5 ms) during the injection period. Kaihei 10-1
The leak amount is greatly reduced as compared with the configuration of JP-A-53155. Also, in the present invention, during the injection period, the second
Of the low pressure chamber 33 reaching the fuel return passages 16 and 17
Is closed, the amount of leak is smaller than in the conventional configuration such as the above-mentioned publication in which the high-pressure portion communicates with the atmospheric pressure chamber even during the injection period. Therefore, the amount of leakage is sufficiently small as a whole, and the amount of pressure supplied by the high-pressure supply pump can be reduced, so that the efficiency of the entire system can be improved.

As shown in FIG. 6 as a second embodiment of the present invention, the present invention can be combined with a well-known nozzle having a two-stage valve opening pressure. In the first embodiment,
Although the nozzle needle 4 opens when the pressure of the nozzle chamber 42 exceeds the urging force of the spring 45, in the present embodiment, in addition to the spring 45, the lower part of the low-pressure chamber 33 is connected to the large-diameter spring chamber 36. Then the second spring 37
Is arranged, and the push rod 38 provided at the upper end of the nozzle needle 4 is urged downward. The push rod 38 penetrates through the spring chamber 44, and the large diameter portion at the upper end is located in the spring chamber 36. The fuel return passage 16 is connected to the spring chamber 36 and the fuel return passage 17
Is connected to the spring chamber 44. Other configurations are the same as those in the first embodiment.

In this configuration, the valve opening pressure at the start of injection causes the second spring 3 that urges the push rod 38 downward.
7 and the urging force of the spring 45 for urging the nozzle needle 4 downward, the initial injection rate can be further reduced.

[Brief description of the drawings]

FIG. 1 is an overall cross-sectional view (when not energized) of an injection valve for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a pressure accumulating fuel injection device including an internal combustion engine injection valve according to the first embodiment.

FIG. 3 is an overall cross-sectional view (when energized) of the injection valve for an internal combustion engine of the first embodiment.

FIG. 4 is a partially enlarged view of the internal combustion engine injection valve according to the first embodiment;

FIG. 5 is a diagram for explaining the operation of the present invention.

FIG. 6 is an overall cross-sectional view (when not energized) of an injection valve for an internal combustion engine showing a second embodiment of the present invention.

FIG. 7 is an overall sectional view of a conventional injection valve for an internal combustion engine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 injection valve 11, 12 upper and lower casing 15 fuel supply passage 16, 17 fuel return passage 2 control valve 2 a first valve portion 2 b second valve portion 21 distal end portion 23 high-pressure passage 31 control chamber (valve chamber) 32 high-pressure chamber ( Valve chamber) 33 Low-pressure chamber (Valve chamber) 34 First seat surface 35 Second seat surface 4 Nozzle needle 41 Nozzle casing 43 Passage 5 Solenoid (drive unit) 51 Solenoid casing 6 Spring 61 Spring chamber

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F02M 47/00 F02M 47/00 NF 47/02 47/02 51/00 51/00 F 61/16 61 / 16 DS (72) Inventor Shigeru Enomoto 14 Iwatani, Shimowasumi-cho, Nishio-shi, Aichi Prefecture Inside Japan Automotive Parts Research Institute (72) Inventor Yuichi Sotozono 1 Toyota-cho, Toyota-shi, Aichi Prefecture Toyota Motor Corporation F term (reference) 3G066 AA07 AB02 AC09 AD12 BA12 BA17 BA25 BA35 BA67 CB16 CC06T CC08T CC14 CC26 CC52 CC61 CC66 CC67 CC68U CD28 CD30 CE13 DA11 DA12 DA13 DA14 DC01 DC09 DC18

Claims (5)

[Claims] 1. An injection valve for injecting high-pressure fuel stored in a common rail into an internal combustion engine, wherein the injection needle slides in a cylindrical casing in an axial direction to open and close an injection hole at a tip of the casing. A nozzle chamber provided on the outer periphery of the nozzle needle in communication with the injection hole and opening the nozzle needle with the pressure of the high-pressure fuel supplied from the common rail; a fuel supply passage communicating with the common rail; and the nozzle chamber. A valve chamber provided between the valve chamber, a control valve disposed in the valve chamber to control the inflow and outflow of high-pressure fuel to and from the nozzle chamber, and a drive unit for driving the control valve. A fuel return passage for discharging high-pressure fuel in the nozzle chamber during non-injection is connected to the control valve, and during fuel injection, the fuel supply passage is opened to guide high-pressure fuel to the nozzle chamber. Preventing fuel from flowing into the fuel return passage, opening the fuel return passage during non-injection to guide high-pressure fuel in the nozzle chamber to the fuel return passage, and preventing fuel from flowing from the fuel supply passage. An injection valve for an internal combustion engine, wherein the injection valve is formed so as to block. 2. The valve chamber is divided into a high pressure chamber to which the fuel supply passage is connected, a control chamber communicating with the nozzle chamber, and a low pressure chamber to which a fuel return passage is connected. A first valve section and a second valve section for opening and closing the control chamber, the high pressure chamber, and the low pressure chamber, respectively, and one of the first and second valve sections is opened when the other is opened. Is formed so as to close the valve, and at the start of injection, the first
The valve section is opened and the second valve section is closed, and high-pressure fuel is supplied from the fuel supply passage to the nozzle chamber via the high-pressure chamber and the valve chamber. And the first valve portion is closed to discharge high-pressure fuel in the nozzle chamber to the fuel return passage via the valve chamber and the low-pressure chamber. An injection valve for an internal combustion engine according to claim 1. 3. The diameter d1 of the sliding portion of the control valve is substantially the same as the seat diameter d2 when the first valve portion is seated and the seat diameter d3 when the second valve portion is seated. An injection valve for an internal combustion engine according to claim 2. 4. The high-pressure chamber, the control chamber, and the low-pressure chamber are disposed coaxially on an extension of a sliding hole in which the control valve slides, and a tip of the control valve is disposed in the control chamber. The first valve portion is disposed on the high pressure chamber side of the distal end portion,
4. The injection valve for an internal combustion engine according to claim 3, wherein the second valve portion is formed on the low pressure chamber side. 5. The second valve portion is formed by extending an end surface of the tip portion on the side of the low-pressure chamber into a cylindrical shape, and the cylindrical second valve portion is formed at an opening edge of the low-pressure chamber having a smaller diameter. 5. An injection valve for an internal combustion engine according to claim 4, wherein said valve portion contacts and closes said valve portion.