JP5195602B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve that is mounted on an internal combustion engine and injects fuel for combustion from an injection hole.

  In order to accurately control the output torque and the emission state of the internal combustion engine, it is important to accurately control the injection state such as the injection start timing and the injection amount of the fuel injected from the fuel injection valve. Therefore, conventionally, there has been proposed a technique for detecting an actual injection state by detecting the pressure of fuel that fluctuates with the injection. For example, the actual injection start time can be detected by detecting the time when the fuel pressure starts to decrease with the start of injection, or the actual injection end time can be determined by detecting the time when the increase in fuel pressure has stopped with the end of injection. Or detected (see Patent Documents 1 to 3).

  When detecting such fluctuations in fuel pressure, the fuel pressure sensor (rail pressure sensor) installed directly on the common rail (accumulation vessel) buffers the fuel pressure fluctuation caused by injection in the common rail. Variation cannot be detected. Therefore, in the inventions described in Patent Documents 1 to 3, by mounting the fuel pressure sensor on the fuel injection valve, it is intended to detect the fuel pressure fluctuation before the fuel pressure fluctuation caused by the injection is buffered in the common rail. .

JP 2008-144749 JP 2009-57926 A JP 2009-57927 A

Although Patent Documents 1 to 3 disclose that the fuel pressure sensor is mounted on the fuel injection valve, the details of the mounting position are not disclosed. Therefore, the present inventors examined a structure in which a fuel pressure sensor 80 is mounted as shown in FIG. 7B, 7C, and 7D are a cross-sectional view taken along line bb, a cross-sectional view taken along line cc, and a cross-sectional view taken along line dd in FIG. 7A, respectively, and FIG. It is an arrow view. In FIG. 7 , hatching indicating a cross section is omitted.

  In the mounting structure of FIG. 7, the high-pressure passage 42 through which the high-pressure fuel supplied from the high-pressure port 44 circulates toward the injection hole is inserted into the main body 40x and the mounting hole 40bx formed in the main body 40x. And a fuel pressure sensor 80 arranged to constitute a fuel injection valve. The fuel pressure sensor 80 includes a strain generating body 81 that elastically deforms under the pressure of high-pressure fuel, and a sensor element 82 that detects the fuel pressure by detecting the amount of strain of the strain generating body 81.

  In the example of FIG. 7, the high-pressure passage 42 includes a first high-pressure passage 42 a extending from the supply port 44 a of the high-pressure port 44 toward the center of the main body 40, and a main body 40 x from the downstream end of the first high-pressure passage 42 a. The second high-pressure passage 42b extends toward the lower end surface (body end surface 40Rx).

  A sensor passage 46x for introducing high-pressure fuel into the fuel pressure sensor 80 is branched from the high-pressure passage 42 inside the main body 40x. The sensor passage 46x is drilled from the bottom surface of the mounting hole 40bx into which the stem 81 is inserted, and is connected to the inlet 81a of the stem 81 and the upstream end of the second high-pressure passage 42b. The second sensor passage 46bx has a shape that branches from the first portion and extends in the vertical direction to the end of the first sensor passage 46ax. According to this, when the second high-pressure passage 42b is drilled upward from the body end surface 40Rx, the second sensor passage 46bx can be processed by extending the drilling length.

  However, in the above-described configuration in which the sensor passage 46x is branched from the high-pressure passage 42, the path of the sensor passage 46x is restricted by the position of the high-pressure passage 42, and the degree of freedom of the attachment position of the fuel pressure sensor 80 is reduced. For example, when the fuel pressure sensor 80 (mounting hole 40bx) is to be disposed at the position indicated by the alternate long and short dash line in FIG. 7B, the first sensor path that connects the bottom surface of the mounting hole 40bx and the second sensor path 46bx. The space for 46ax cannot be secured, and the space for the mounting hole 40b and the first sensor passage 46ax cannot be secured unless the main body 40x is enlarged in the radial direction as indicated by reference numeral 40dx in FIG. In other words, when drilling the first sensor passage 46ax, it is necessary to enlarge the body body 40x in order to secure a processing space (a drill insertion space indicated by an arrow Y in FIG. 7F).

  In view of this problem, the present inventors have studied a configuration in which the second sensor passage 460bx is branched at an angle different from that of the second high-pressure passage 42b as shown by a one-dot chain line in FIG. According to this, it can suppress that the path | route of the 2nd sensor channel | path 460bx is restrict | limited by the position of the 2nd high voltage | pressure channel | path 42b, and can improve the freedom degree of the attachment position of the fuel pressure sensor 80 (attachment hole 40bx). However, as a contradiction, the shape of the branch portion 40ex that branches the second sensor passage 460bx from the high pressure passage 42 becomes a shape in which stress due to the high pressure fuel tends to concentrate, and the number of the stress concentration portions 40ex, 40fx increases. The pressure resistance inside the main body 40x against high pressure fuel is reduced.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to attach a fuel pressure sensor to a fuel injection valve having a fuel pressure sensor while suppressing a decrease in pressure resistance inside the main body body with respect to high pressure fuel. An object of the present invention is to provide a fuel injection valve that improves the degree of freedom of position.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

The invention according to claim 1 is a main body provided with a high-pressure port to which high-pressure fuel is supplied, a nozzle body in which an injection hole for injecting high-pressure fuel supplied from the high-pressure port is formed, and attached to the main body A fuel pressure sensor for detecting the pressure of the high-pressure fuel, and a high-pressure passage for allowing the high-pressure fuel supplied from the high-pressure port to flow toward the nozzle hole in the main body, and the fuel pressure sensor A sensor passage for guiding high-pressure fuel is formed. And by forming the outlet of the high-pressure passage and the introduction port of the sensor passage on the body end surface, which is the end surface on the nozzle body side of the main body, at least the inside of the main body except for the body end surface Then, both the passages are formed separately from each other so that the sensor passage and the high-pressure passage do not communicate with each other.

  According to the present invention, the sensor passage and the high-pressure passage are formed separately from each other inside the main body, so that a branching portion that branches the sensor passage from the high-pressure passage can be eliminated. Therefore, since the stress concentration location inside the main body body can be reduced, it is possible to suppress a decrease in pressure resistance inside the main body body with respect to the high pressure fuel.

  Furthermore, according to the present invention, the sensor passage and the high-pressure passage are formed separately from each other inside the main body, so that the passage of the sensor passage can be suppressed from being restricted by the position of the high-pressure passage, and the fuel pressure sensor can be attached. The degree of freedom of position can be improved. For example, even when it is desired to change the position of the fuel pressure sensor (mounting hole 40b) to the respective positions shown in FIGS. 3B, 3F, and 3H, the position of the sensor passage is moved to the position indicated by reference numeral 46b. Thus, the space of the mounting hole 40b for inserting and arranging the fuel pressure sensor can be easily secured without expanding the main body 40 in the radial direction.

  As described above, according to the present invention, the sensor passage and the high-pressure passage are formed separately from each other inside the main body, so that the deterioration of the pressure resistance inside the main body with respect to the high-pressure fuel is suppressed, and the mounting position of the fuel pressure sensor is reduced. The degree of freedom can be improved.

  Here, in order to introduce high-pressure fuel from the high-pressure path including the high-pressure path to the sensor path including the sensor path, a communication path that connects both paths is required. For example, a through hole is formed in the main body body or the nozzle body. When the communication path is used, it is difficult to secure the space for arranging the through holes.

  In view of this point, the invention according to claim 2 is characterized in that a groove is formed on the end surface of the body, and the outlet of the high-pressure passage and the inlet of the sensor passage are communicated with each other by the groove. According to this, since the said communicating path will be comprised by a groove part, compared with the case where a through-hole is comprised as said communicating path, the arrangement space of a communicating path (groove part) can be ensured easily.

  According to a third aspect of the present invention, a groove portion is formed in a nozzle end surface that is an end surface on the main body side of the nozzle body, and the high pressure path including the high pressure passage and the sensor path including the sensor passage are formed by the groove portion. Characterized by communication. According to this, since the said communicating path will be comprised by a groove part, compared with the case where a through-hole is comprised as said communicating path, the arrangement space of a communicating path (groove part) can be ensured easily.

  According to a fourth aspect of the present invention, an orifice plate is disposed adjacent to a nozzle end surface that is an end surface on the main body side of the nozzle body, and a lower end surface of the plate that is an end surface on the nozzle body side of the orifice plate is provided. A groove is formed, and the high pressure path including the high pressure passage communicates with the sensor path including the sensor path by the groove. According to this, since the said communicating path will be comprised by a groove part, compared with the case where a through-hole is comprised as said communicating path, the arrangement space of a communicating path (groove part) can be ensured easily.

  According to a fifth aspect of the present invention, the nozzle body includes an orifice plate disposed between the nozzle end surface which is an end surface on the body body side of the nozzle body and the body end surface, and the main body of the orifice plate is provided. A groove is formed on the upper end surface of the plate, which is an end surface on the body side, and the high pressure path including the high pressure passage communicates with the sensor path including the sensor path by the groove. According to this, since the said communicating path will be comprised by a groove part, compared with the case where a through-hole is comprised as said communicating path, the arrangement space of a communicating path (groove part) can be ensured easily.

  According to a sixth aspect of the present invention, an annular passage for annularly distributing the high-pressure fuel flowing out from the outlet of the high-pressure passage is provided, and an annular groove formed as a part of the annular passage is used as the groove. And

  Here, a general fuel injection valve structure forms a passage (needle outer peripheral passage) through which high-pressure fuel flows toward the injection hole between the outer peripheral surface of the needle and the inner peripheral surface of the nozzle body. However, since this needle outer peripheral passage has an annular shape surrounding the outer peripheral surface of the needle, high pressure fuel flowing out from the outlet of the high pressure passage is placed in the upstream portion of the needle outer peripheral passage out of the high pressure passage including the high pressure passage. An annular passage distributed in an annular shape is required.

  In the above-described invention focusing on this point, the annular groove formed as a part of such an annular passage is used as the groove that communicates the high-pressure path including the high-pressure passage and the sensor path including the sensor passage. It is unnecessary to form a groove portion separately from the annular groove portion.

1 is an overall cross-sectional view of a fuel injection valve according to a first embodiment of the present invention. The enlarged view of FIG. (A) is a figure which shows only the main body in FIG. 1, (b) is a bb cross section of (a), (c) is a cc cross section of (a), (d) is d of (a). -D cross section, (e) is a diagram showing an e arrow view of (a). The IV arrow line view of FIG. 2 which shows 2nd Embodiment of this invention. The V arrow figure of FIG. 2 which shows 3rd Embodiment of this invention. The VI arrow directional view of FIG. 2 which shows 4th Embodiment of this invention. FIG. 4 is a cross-sectional view showing a configuration of a main body different from the present invention, which is a fuel injection valve investigated by the present inventors.

  Embodiments in which a fuel injection valve according to the present invention is applied to a common rail fuel injection system of a diesel engine (internal combustion engine) mounted on a vehicle will be described below with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are denoted by the same reference numerals in the drawings, and the description of the same reference numerals is used.

(First embodiment)
1 is an overall cross-sectional view of the fuel injection valve 10, and FIG. 2 is an enlarged view of FIG. The fuel injection valve 10 is inserted and mounted in a cylinder head (not shown) of the engine, and directly injects fuel supplied from a common rail into the combustion chamber E1 of each cylinder of the engine.

  First, the overall structure of the fuel injection valve 10 will be described with reference to FIG. The fuel injection valve 10 includes a nozzle body 20, a needle 30, a main body 40, an orifice plate 50, an electromagnetic unit 60, and the like.

  A part of the nozzle body 20 and the main body 40 is inserted and disposed in a body insertion hole E3 formed in a cylinder head E2 of the internal combustion engine. The body body 40 is formed with an engaging portion 40a (pressing surface) that engages with one end of the clamp K. By tightening the other end of the clamp K to the cylinder head E2 with a bolt, one end of the clamp K is engaged. The part 40a is pressed toward the body insertion hole E3. Thereby, the fuel injection valve is fixed in a state of being pressed into the body insertion hole E3.

  The nozzle body 20 is fixed to the lower side (injection hole side) of the main body body 40 via the orifice plate 50 by the retaining nut 11. The nozzle body 20 is formed with a guide hole 21 (needle accommodating chamber) for slidably accommodating the needle 30 and an injection hole 22 for injecting fuel when the needle 30 is lifted up. Hereinafter, the nozzle hole 20 side (lower side in FIG. 1) is referred to as “lower side”, and the opposite side (upper side in FIG. 1) of the nozzle hole 22 is referred to as “upper side”.

  The guide hole 21 is drilled from the upper end surface of the nozzle body 20 toward the tip of the nozzle body 20, and a high-pressure passage 23 that guides high-pressure fuel to the injection hole 22 through a gap between the inner peripheral surface of the guide hole 21 and the outer peripheral surface of the needle 30. Is formed. Further, a fuel reservoir chamber 24 in which the inner diameter of the nozzle body 20 is enlarged is formed in the middle of the guide hole 21. The high-pressure passage 23 (guide hole 21) is connected to a high-pressure passage 51 formed in the orifice plate 50 with an upstream end opened to the upper end surface of the nozzle body 20.

  A conical seating surface 221 (see FIG. 2) is formed at the tip of the high pressure passage 23 on the inner peripheral surface of the nozzle body 20, and a seat surface 331 (see FIG. 2) seated on the seating surface 221 at the tip of the needle 30. Reference) is formed. When the seat surface 331 is seated on the seating surface 221, the needle 30 blocks and blocks the high-pressure passage 23 leading to the nozzle hole 22.

  A cylindrical cylinder 25 is disposed in the guide hole 21, and a spring that presses the needle 30 in the valve closing direction (downward in FIG. 1) between the lower end surface of the cylinder 25 and the upper end surface of the needle 30. 26 is arranged. A back pressure chamber 27 is formed on the inner peripheral surface of the cylinder 25 to apply a high pressure fuel pressure as a back pressure to the upper end surface of the needle. This back pressure biases the needle 30 in the valve closing direction (downward in FIG. 1). Further, the pressure of the high-pressure fuel in the fuel reservoir 24 urges the needle 30 in the valve opening direction (upward in FIG. 1).

  A high-pressure port 44 (high-pressure pipe connection portion) connected to a high-pressure pipe (not shown) and a low-pressure port 45 (low-pressure pipe connection portion) connected to a low-pressure pipe (not shown) are provided on the outer peripheral surface of the main body 40 having a substantially cylindrical shape. Is formed. The fuel supplied from the common rail to the high-pressure port 44 through the high-pressure pipe is supplied from the outer peripheral surface side of the cylindrical main body 40.

  A high pressure passage 42 for guiding the high pressure fuel introduced into the high pressure port 44 to the high pressure passage 23 of the nozzle body 20 through the high pressure passage 51 of the orifice plate 50 and the electromagnetic unit 60 are inserted into the main body 40. An accommodation hole 43, a sensor passage 46, a lead wire insertion hole 47, and the like, which will be described later, are formed. The high pressure passage 42 and the accommodation hole 43 have a shape extending in the axial direction of the fuel injection valve 10 (vertical direction in FIG. 1). The “axial direction” referred to in the present specification is the longitudinal direction of the fuel injection valve 10, and is also the insertion direction of the fuel injection valve 10 inserted and mounted in the cylinder head.

  In the present embodiment, the electromagnetic unit 60 and the high-pressure passage 42 are laid out in a direction perpendicular to the axial direction of the main body 40 (the left-right direction in FIG. 1).

  As shown in FIG. 2, the orifice plate 50 is formed with an inflow passage 52 through which high-pressure fuel flows from the high-pressure passage 51 to the back pressure chamber 27 and an outflow passage 53 through which the high-pressure fuel flows out from the back pressure chamber 27 to the low pressure side. Yes. An inflow side orifice 52 a is formed in the inflow passage 52, and an outflow side orifice 53 a is formed in the outflow passage 53.

  The electromagnetic unit 60 includes a stator 63 having an electromagnetic coil 62, an armature 64 that is movable facing the stator 63, a ball valve 65 (control valve) that moves integrally with the armature 64, and opens and closes the outlet orifice 53a. It is configured with.

  A resin connector housing 70 (see FIG. 1) is attached to the upper portion of the main body 40, and a drive connector terminal 72 (see FIG. 1) and an electromagnetic coil 62 provided on the connector housing 70 are connected to lead wires 73. Are electrically connected.

  Incidentally, the lead wire 73 is inserted and arranged in the lead wire insertion hole 47 formed in the main body 40 while being held by the holding member 73a (see FIG. 1). The holding member 73a is made of a material (for example, a resin such as nylon) having a hardness lower than that of the metal in order to prevent the covering of the lead wire 73 from being worn. In addition, the holding member 73 a has a shape, a thickness, and the like that are higher in rigidity than the lead wire 73.

  When the electromagnetic coil 62 is energized, the armature 64 is attracted to the stator 63 and moved. Further, the spring 66 housed in the central portion of the stator 63 urges the armature 64 in the direction in which the ball valve 65 is closed (downward in FIG. 2).

  An annular groove 56 is formed in the lower end surface of the orifice plate 50, and the high pressure passage 51 of the orifice plate 50 and the high pressure passage 23 of the nozzle body 20 communicate with each other through the annular groove 56. At the downstream end of the high-pressure passage 51, an expansion chamber 51a having an enlarged channel cross-sectional area so as to be connected to the annular groove 56 is formed.

  In the middle of the high-pressure passage 23 formed in the nozzle body 20, a spring housing for housing an annular groove 25 a and a spring 26 formed between the outer peripheral surface of the cylinder 25 and the inner peripheral surface of the nozzle body 20 in order from the upstream side. There are a portion 23a, a chamfered portion 30a formed on the side surface of the needle 30, a fuel reservoir chamber 24, and the like.

  Here, the pressure of the high-pressure fuel in the nozzle body 20 and the main body 40 varies with the fuel injection from the nozzle hole 22. A fuel pressure sensor 80 for detecting the pressure fluctuation is attached to the main body 40 (see FIG. 1). In the pressure fluctuation waveform detected by the fuel pressure sensor 80, the actual injection start timing can be detected by detecting the timing at which the fuel pressure starts decreasing with the start of injection from the nozzle hole 22. Moreover, the actual injection end time can be detected by detecting the time when the fuel pressure starts to increase with the end of injection. Further, in addition to the injection start timing and the injection end timing, the injection amount can be detected by detecting the maximum value of the fuel pressure decrease amount caused by the injection.

  Returning to the description of FIG. 1, the fuel pressure sensor 80 includes a stem 81 (a strain generating body) that is elastically deformed by the pressure of high-pressure fuel in the sensor passage 46, which will be described in detail later, and the magnitude of strain generated in the stem 81. And a strain gauge 82 (sensor element) that converts the signal into an electric signal and outputs it as a pressure detection value.

  The stem 81 includes a cylindrical cylindrical portion 81b in which an inflow port 81a for introducing high-pressure fuel therein is formed at one end, and a disc-shaped diaphragm portion 81c that closes the other end of the cylindrical portion 81b. ing. The pressure of the high-pressure fuel flowing into the cylindrical portion 81b from the inflow port 81a is received by the inner surface of the cylindrical portion 81b and the diaphragm portion 81c, whereby the entire stem 81 is elastically deformed.

  The stem 81 is made of metal, and since the metal material is subjected to ultra-high pressure, it has high strength and high hardness, and deformation due to thermal expansion is small, and the strain gauge 82 is less affected (that is, a low thermal expansion coefficient). Specifically, a material mainly composed of Fe, Ni, Co or Fe, Ni and Ti, Nb, Al or Ti, Nb added as a precipitation strengthening material is selected and pressed. It can be formed by cutting or cold forging. Moreover, you may select the material to which C, Si, Mn, P, S, etc. were added.

  A mounting hole 40b into which the cylindrical portion 81b of the stem 81 is inserted is formed on the circumferential side surface of the main body 40 formed in a substantially columnar shape. The fuel pressure sensor 80 is attached to the body body 40 by screwing the male screw portion 81d formed on the outer peripheral surface of the cylindrical portion 81b of the stem 81 to the female screw portion formed on the inner peripheral surface of the mounting hole 40b. It is attached.

  A sensor-side sealing surface 81e is formed on the cylindrical end surface of the cylindrical portion 81b located around the inflow port 81a, and a body-side sealing surface 40c is formed on the bottom surface of the mounting hole 40b. Both the sealing surfaces 81e and 40c are surfaces extending in a direction perpendicular to the axial direction of the stem 81 (the left-right direction in FIG. 1), and have a shape extending in an annular shape around the inflow port 81a.

  The sensor-side seal surface 81e is pressed against the body-side seal surface 40c so that the sensor-side seal surface 81e is brought into close contact with the body-side body 40 and the stem 81, thereby performing a metal touch seal. The force (axial force) that presses both the seal surfaces 81e and 40c is generated by screwing the stem 81 to the main body 40. That is, the attachment of the stem 81 to the main body 40 and the generation of the axial force are performed simultaneously.

  The strain gauge 82 is attached to the diaphragm portion 81c. Therefore, when the stem 81 is elastically deformed to expand due to the pressure of the high-pressure fuel flowing into the cylindrical portion 81b, the strain gauge 82 detects the magnitude of the strain (elastic deformation amount) generated in the diaphragm portion 81c. .

  A metal holding member 83 is attached to the stem 81, and an electronic component 84 composed of an IC or the like is held on the holding member 83. The electronic component 84 is electrically connected to the strain gauge 82 by wire bonding, and an amplification circuit that amplifies a detection signal output from the strain gauge 82, a filtering circuit that removes noise superimposed on the detection signal, and the strain gauge 82. A circuit or the like for applying a voltage is configured.

  Note that the strain gauge 82 to which a voltage is applied from the voltage application circuit constitutes a bridge circuit whose resistance value changes according to the magnitude of the strain generated in the diaphragm portion 81c. As a result, the output voltage of the bridge circuit changes according to the distortion of the diaphragm portion 81c, and the output voltage is output to the amplifier circuit of the electronic component 84 as the pressure detection value of the high-pressure fuel. The amplifier circuit amplifies the pressure detection value output from the strain gauge 82 (bridge circuit) and outputs the amplified signal from the sensor terminal 85.

  The holding member 83 holds a plurality of sensor terminals 85 connected to the electronic component 84. These sensor terminals 85 are a terminal for outputting a detection signal of the fuel pressure sensor 80, a terminal for supplying power, and a grounding terminal. And so on. In addition to the electronic component 84, a strain gauge 82 is accommodated in the holding member 83. Accordingly, the metal holding member 83 blocks external noise and protects the strain gauge 82 and the electronic component 84.

  The connector housing 70 holds the sensor connector terminal 71 together with the drive connector terminal 72. The sensor connector terminal 71 and the sensor terminal 85 are electrically connected by laser welding or the like via electrodes 86a, 86b, 86c described later. A connector composed of the connector housing 70 and the connector terminals 71 and 72 is connected to a connector of an external harness that is connected to an external device such as an engine ECU (not shown). Thereby, the pressure detection signal output from the electronic component 84 is input into the engine ECU via the external harness.

  Here, when the stem 81 is rotated and the stem 81 is screwed to the main body 40, the rotational position of the stem 81 is not fixed at a specific position when the screw fastening is completed. This means that the rotational positions of the plurality of sensor terminals 85 are unspecified when the screw fastening of the stem 81 is completed.

  Therefore, the electrodes 86 a and 86 b connected to each of the sensor terminals 85 and rotating together with the stem 81 are formed in a shape extending in an annular shape around the rotation center of the stem 81. The annular electrodes 86 a and 86 b are electrically connected to each of the plurality of connector terminals 71 after the screw fastening of the stem 81 is completed. Thereby, the sensor terminal 85b whose rotational position is unspecified and the connector terminal 71 arranged at a predetermined position of the main body 40 can be easily electrically connected. Since the electrode 86c located at the center of the annular electrodes 86a and 86b is located at the rotation center of the stem 81, the rotation position is specified regardless of the rotation position of the stem 81.

  Next, the operation of the fuel injection valve 10 will be described.

  When the energization of the electromagnetic coil 62 is stopped, the ball valve 65 closes the outflow side orifice 53a, and therefore the force that biases the needle 30 in the valve closing direction (according to the fuel pressure of the back pressure chamber 27). The force + the urging force of the spring 26) becomes larger than the force that pushes the needle 30 in the valve opening direction (the lift force due to the fuel pressure of the fuel reservoir 24). As a result, the seat surface 331 of the needle 30 is seated on the seating surface 221, and the fuel is not injected by blocking between the high-pressure passage 23 and the injection hole 22.

  When the electromagnetic coil 62 is energized, the armature 64 is attracted to the magnetized stator 63, and the armature 64 moves toward the stator 63 against the biasing force of the spring 66, so that the ball valve 65 is moved back. In response to the fuel pressure in the pressure chamber 27, the outlet orifice 53a is opened. Therefore, the high pressure fuel in the back pressure chamber 27 is opened to the low pressure side through the outflow side orifice 53a.

  Since both the orifices 53a and 52a are set so that the outflow amount from the outflow side orifice 53a with respect to the back pressure chamber 27 is larger than the inflow amount from the inflow side orifice 52a, the back valve chamber is opened when the ball valve 65 is opened as described above. The fuel pressure in the pressure chamber 27 decreases. As a result, the needle 30 is lifted when the force that pushes the needle 30 in the valve opening direction (lift force due to the fuel pressure in the fuel reservoir chamber 24) exceeds the force that biases the needle 30 in the valve closing direction. Then, the high-pressure fuel supplied from the common rail to the fuel injection valve 10 is injected from the injection hole 22 through the high-pressure passage 42 of the main body, the high-pressure passage 51 of the orifice plate 50, and the high-pressure passage 23 of the nozzle body 20.

  Next, the single-piece | unit structure of the main body 40 is demonstrated using FIG.

  3A is a cross-sectional view of the body body 40 showing the same cross section as FIG. 1, FIG. 3B is a cross-sectional view taken along line bb in FIG. 3A, and FIG. 3C is a cross-sectional view taken along line cc in FIG. (D) is dd sectional drawing of (a), (e) is the e arrow directional view of (a). In FIG. 3, hatching indicating a cross section is omitted.

  Inside the main body 40, the above-described high-pressure passage 42, sensor passage 46, lead wire insertion hole 47, and low-pressure passage 45b are formed. The low-pressure passage 45b is a passage for guiding the low-pressure fuel discharged from the outflow side orifice 53a to the discharge port 45a of the low-pressure port 45. The details of the route of the low-pressure passage 45b inside the main body 40 are not shown. Omitted.

  The high-pressure passage 42 includes a first high-pressure passage 42a and a second high-pressure passage 42b that are formed by drilling separately. The first high pressure passage 42 a has a shape extending from the supply port 44 a of the high pressure port 44 toward the center of the main body 40. The second high-pressure passage 42b is a passage that forms a high-pressure route from the downstream end of the first high-pressure passage 42a to the outlet 42c formed in the lower end surface (body end surface 40R) of the main body 40. The shape extends in the axial direction of the body 40.

  The sensor passage 46 is a passage for guiding high-pressure fuel to the inlet 81a of the stem 81, and includes a first sensor passage 46a and a second sensor passage 46b formed by drilling separately. Yes. The first sensor passage 46 a has a shape extending perpendicularly to the axial direction of the main body 40 from the bottom surface of the mounting hole 40 b into which the stem 81 is inserted, and is arranged to communicate with the inlet 81 a of the stem 81. . The second sensor passage 46b is a passage that forms a high-pressure path from the end of the first sensor passage 46a to the inlet 46c formed in the body end surface 40R, and has a shape that extends in the axial direction of the main body 40. is there.

  The housing hole 43 and the lead wire insertion hole 47 communicate with each other, and an outlet 47a for taking out the lead wire 73 from the lead wire insertion hole 47 to the outside of the main body 40 is formed on the side surface of the main body. Further, an insertion port 43a for inserting the electromagnetic unit 60 into the accommodation hole 43 is formed in the body end surface 40R.

  In short, the outlet end 42c of the high-pressure passage 42, the introduction port 46c of the sensor passage 46, and the insertion port 43a of the accommodation hole 43 are formed in the body end surface 40R (see FIG. 3 (e)).

  The second high-pressure passage 42b extending upward from the outlet 42c, the second sensor passage 46b extending upward from the introduction port 46c, the housing hole 43 extending upward from the insertion port 43a, and a part of the lead wire insertion hole 47, Are arranged in parallel (see FIG. 3D). The second high-pressure passage 42b, the second sensor passage 46b, the accommodation hole 43, and the lead wire insertion hole 47 are each formed by drilling upward from the body end surface 40R. That is, at least inside the main body 40, the passages 46 and 42 are formed separately from each other so that the sensor passage 46 and the high-pressure passage 42 do not communicate with each other.

  The upper end of the second high-pressure passage 42b and the upper end of the lead wire insertion hole 47 are located below the upper end of the second sensor passage 46b. Therefore, only the second sensor passage 46b is formed in the cross section (cc cross section) of the upper end portion of the main body 40 (see FIG. 3C).

  Further, as shown in FIG. 3E, a groove 40m is formed on the body end surface 40R to connect the outlet 42c of the high-pressure passage 42 and the inlet 46c of the sensor passage 46. Therefore, the high-pressure fuel in the high-pressure passage 42 flows into the inlet 46c of the sensor passage 46 through the groove 40m.

  The outlet 42c of the high-pressure passage 42 communicates with the high-pressure passage 51 formed in the orifice plate 50, whereas the inlet 46c and the groove 40m of the sensor passage 46 are connected to the upper end surface (plate upper end surface) of the orifice plate 50. 50S).

  As described above, according to the present embodiment, the passages 46 and 42 are formed separately from each other so that the sensor passage 46 and the high-pressure passage 42 do not communicate with each other at least inside the main body 40. A branching portion that branches the passage 46 can be eliminated. Therefore, since the stress concentration location in the main body 40 can be reduced, it is possible to suppress a decrease in pressure resistance in the main body 40 with respect to the high pressure fuel.

  Furthermore, according to the present embodiment, the sensor passage 46 and the high-pressure passage 42 are separately and independently formed inside the main body 40, so that the path of the sensor passage 46 can be suppressed from being restricted by the position of the high-pressure passage 42, The degree of freedom of the mounting position of the stem 81 (the direction of the mounting hole 40b) can be improved.

  For example, even if the mounting hole 40b is to be arranged in the direction shown in FIG. 3 (f), the position of the introduction port 46c on the body end surface 40R is changed as shown in FIG. What is necessary is just to change the drilling position of 46b. Further, even when the mounting hole 40b is to be arranged in the direction shown in FIG. 3 (h), the drilling position of the second sensor passage 46b is changed and the insertion direction of the stem 81 into the mounting hole 40b (see FIG. The direction of the first sensor passage 46a may be inclined with respect to 3 (h) in the left-right direction). As described above, the space for the mounting hole 40b can be easily secured without enlarging the main body 40 in the radial direction. In addition, the arrow shown by the code | symbol Y in FIG.3 (h) has shown the direction which inserts a drill in the attachment hole 40b in drilling the 1st sensor channel | path 46a, and inserts a drill from the opening of the attachment hole 40b. The first sensor passage 46a is laid out so that it is possible.

  Further, according to the present embodiment, the groove portion 40m is formed in the body end surface 40R, and the outlet portion 42c of the high-pressure passage 42 and the introduction port 46c of the sensor passage 46 are communicated by the groove portion 40m. Compared to the case where the hole is formed and the high-pressure passage 42 and the sensor passage 46 are communicated with each other through the through-hole, the arrangement space of the communication passage (groove portion 40m) can be easily secured.

  Moreover, according to this embodiment, since the stem 81 is formed separately from the main body 40, the following effects are exhibited.

  That is, when the internal stress of the main body 40 caused by thermal expansion and contraction is propagated to the stem 81, the propagation loss can be increased. That is, by configuring the stem 81 separately from the main body 40, the influence on the stem 81 due to distortion of the main body 40 is reduced. Therefore, according to this embodiment in which the sensor element 82 is attached to the stem 81 configured separately from the main body 40, the sensor element 82 is generated in the main body 40 compared to the case where the sensor element 82 is directly attached to the main body 40. It can suppress that the sensor element 82 receives the influence of distortion. Therefore, the accuracy of fuel pressure detection by the fuel pressure sensor 80 can be improved.

  In addition, since the material of the stem 81 is a material having a smaller thermal expansion coefficient than that of the main body, the stem 81 itself can be prevented from being distorted due to thermal expansion and contraction. In addition, since only the stem 81 needs to be made of a material having a small thermal expansion coefficient as compared with the case where the entire body body 40 is made of a material having a small thermal expansion coefficient, the material cost can be reduced.

  In addition, since it is possible to inspect whether the output value of the sensor element 82 is abnormal before the stem 81 with the sensor element 82 attached is attached to the main body 40, the workability of the inspection can be improved.

(Second Embodiment)
In the first embodiment, the communication path that allows the high-pressure path 42 and the sensor path 46 to communicate with each other is constituted by the groove 40m formed in the body end surface 40R. On the other hand, in the present embodiment shown in FIG. 4 (viewed in the direction of arrow IV in FIG. 2), the groove portion 40m of the body end surface 40R is eliminated, and the groove portion 50m formed on the upper end surface (plate upper end surface 50S) of the orifice plate 50. Constitutes the communication path. Also in this embodiment, the same effect as the first embodiment is exhibited.

(Third embodiment)
In the first embodiment, the communication path that allows the high-pressure path 42 and the sensor path 46 to communicate with each other is constituted by the groove 40m formed in the body end surface 40R. On the other hand, in the present embodiment shown in FIG. 5 (viewed in the direction of arrow V in FIG. 2), the groove portion 40m of the body end surface 40R is eliminated, and the annular groove portion 56 formed on the lower end surface (plate lower end surface 50R) of the orifice plate 50. As a result, a communication path that connects the third sensor path 460 (sensor path) described below and the high-pressure path 51 is configured.

  In this case, high-pressure fuel is introduced into the stem 81 from the high-pressure path including the high-pressure paths 42 and 51 by the sensor path 46 including the first sensor path 46 a and the second sensor path 46 b and the third sensor path 460. . The third sensor passage 460 has a shape that penetrates the orifice plate 50. The upper end opening of the third sensor passage 460 communicates with the outlet 42 c of the second high-pressure passage 42 b, and the lower end opening 460 a of the third sensor passage 460 communicates with the annular groove 56.

  As described above, the annular groove portion 56 is for communicating the high pressure passage 51 of the orifice plate 50 with the high pressure passage 23 of the nozzle body 20. The high pressure passage 23 of the nozzle body 20 has an annular shape that surrounds the outer peripheral surface of the needle 30, and the annular groove portion 56 is also formed in an annular shape in accordance with the shape of the high pressure passage 23.

  By the way, when the fuel pressure in the high-pressure passage 42 was measured, it was found that various disturbances were superimposed on the measured values in addition to the fuel pressure fluctuation generated in the nozzle hole 22 due to the injection. Specific examples of the disturbance include a reflected wave in which the fuel pressure fluctuation generated in the nozzle hole 22 is reflected on the upstream side portion of the supply port 44a and reflected to the high-pressure passage 42, or fuel is supplied to the supply port 44a while pulsating. Fuel pressure pulsation and the like. When disturbances are superposed in this way, there is a concern that the detection accuracy may be deteriorated in detecting the fuel pressure fluctuation generated in the nozzle hole 22 based on the detection value of the fuel pressure sensor 80.

  In response to this concern, according to the present embodiment, the high-pressure fuel is introduced into the sensor passage 46 from the annular groove portion 56 formed in an annular shape, so that the superposition of disturbance can be suppressed for the following reason. That is, since the annular groove portion 56 is formed in an annular shape, the passage sectional area of the annular groove portion 56 is larger than the passage sectional areas of the high-pressure passages 42 and 51. Therefore, the high-pressure fuel that has flowed into the annular groove 56 from the high-pressure passages 42 and 51 is stored in the annular groove 56, so that the disturbance is buffered in the annular groove 56. Therefore, since the high-pressure fuel in a state where the disturbance is buffered is taken into the sensor passage 46 and introduced into the inlet 81a of the stem 81, it is possible to suppress the disturbance from being superimposed on the detection value of the fuel pressure sensor 80.

  As described above, according to the present embodiment in which the high-pressure fuel is introduced into the sensor passage 46 from the annular groove portion 56 formed in the annular shape, the sensor passage 46x is opened from the high-pressure passage 42 inside the main body 40x as shown in FIG. Compared with the case of branching, it is possible to suppress the disturbance from being superimposed on the detection value of the fuel pressure sensor 80, and to detect the fuel pressure fluctuation generated in the nozzle hole 22 with high accuracy.

  Furthermore, according to this embodiment, the high-pressure fuel that has flowed out of the outlet 42 c of the high-pressure passage 42 and circulated through the high-pressure passage 51 is distributed annularly in the annular passage constituted by the high-pressure passage 23 and the annular groove portion 56. An annular groove portion 56 formed as a part of the annular passage and provided to communicate the high pressure passage 51 of the orifice plate 50 and the high pressure passage 23 of the nozzle body 20 is provided with a high pressure passage 51 (high pressure passage) and a third sensor passage. Since it is used as a groove part (communication path) for communicating with 46d (sensor path), it is not necessary to form a groove part separately from the annular groove part 56, and the configuration for communicating the high-pressure path and the sensor path can be simplified.

(Fourth embodiment)
In the third embodiment, the communication path that connects the third sensor path 460 (sensor path) and the high-pressure path 51 (high-pressure path) is constituted by the annular groove portion 56 formed in the plate lower end surface 50R. On the other hand, in the present embodiment shown in FIG. 6 (viewed in the direction of arrow VI in FIG. 2), the annular groove portion 56b formed on the upper end surface (nozzle end surface 20S) of the nozzle body 20 is eliminated by eliminating the annular groove portion 56 on the plate lower end surface 50R. Thus, a communication path that connects the third sensor path 460 (sensor path) and the high-pressure path 51 (high-pressure path) is configured. Also in this embodiment, the same effect as the third embodiment is exhibited.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be modified as follows. Moreover, you may make it combine the characteristic structure of each embodiment arbitrarily, respectively.

  In the first embodiment, the stem 81 is configured separately from the main body 40, but may be configured integrally. In this case, a thin portion may be formed in the main body 40 so as to function as the diaphragm portion 81c, and the sensor element 82 may be attached to the thin portion.

  In the first embodiment, the electromagnetic unit 60 composed of a stator and an armature is used as an electric actuator that opens and closes the needle 30. However, a laminated body (piezo stack) formed by laminating a large number of piezoelectric elements. A configured piezo actuator may be employed.

  In each of the embodiments described above, the present invention is applied to a fuel injection valve configured to be provided with the mounting hole 40b in the outer peripheral portion of the main body body 40 and to insert the stem 81 into the mounting hole 40b from the outer peripheral surface side of the main body body 40. However, even if the mounting hole 40b is provided in the upper end portion of the main body body 40 and the stem 81 is inserted into the mounting hole 40b from the upper end side of the main body body 40, the present invention may be applied. Good.

  In each of the above embodiments, the present invention is applied to a fuel injection valve that is provided with a high-pressure port 44 in the outer peripheral portion of the main body 40 and configured to supply high-pressure fuel from the outer peripheral surface side of the main body 40. Further, the present invention may be applied to a so-called pencil type fuel injection valve in which a high-pressure port 44 is provided at the upper end portion of the main body 40 and high-pressure fuel is supplied from the opposite injection hole side of the main body 40. .

  In each of the above embodiments, the second sensor passage 46b is formed to extend parallel to the axial direction of the main body 40, but may be formed to be inclined with respect to the axial direction. Similarly, the second high-pressure passage 42b may be formed to be inclined with respect to the axial direction.

  In each of the above embodiments, the present invention is applied to an injector of a diesel engine. However, the present invention may be applied to a gasoline engine, particularly, a direct injection gasoline engine that directly injects fuel into a combustion chamber.

  DESCRIPTION OF SYMBOLS 10 ... Fuel injection valve, 20 ... Nozzle body, 22 ... Injection hole, 23 ... High pressure passage (annular passage), 23b ... The annular groove part formed in the nozzle end surface, 40 ... Main body body, 40m ... The groove part formed in the body end surface, 40R ... Body end face, 42 ... High pressure passage, 42c ... Outlet, 44 ... High pressure port, 46 ... Sensor passage, 46c ... Inlet, 50m ... Groove formed on the upper end surface of the plate, 56 ... Formed on the lower end surface of the plate An annular groove 80, a fuel pressure sensor.

Claims (6)

A body body provided with a high-pressure port to which high-pressure fuel is supplied;
A nozzle body in which a nozzle hole for injecting high-pressure fuel supplied from the high-pressure port is formed;
A fuel pressure sensor attached to the body body for detecting the pressure of the high-pressure fuel;
With
Inside the body body, a high-pressure passage for flowing high-pressure fuel supplied from the high-pressure port toward the nozzle hole, and a sensor passage for guiding high-pressure fuel to the fuel pressure sensor are formed,
By forming an outlet of the high-pressure passage and an introduction port of the sensor passage on a body end surface that is an end surface on the nozzle body side of the body body, at least inside the body body except the body end surface. A fuel injection valve characterized in that both the passages are formed separately from each other so that the sensor passage and the high-pressure passage do not communicate with each other.   2. The fuel injection valve according to claim 1, wherein a groove is formed in the end surface of the body, and the outlet of the high-pressure passage and the inlet of the sensor passage are communicated with each other by the groove.   A groove portion is formed in a nozzle end surface which is an end surface on the main body side of the nozzle body, and the high pressure path including the high pressure passage and the sensor path including the sensor passage are communicated with each other by the groove portion. The fuel injection valve according to claim 1. Inside the nozzle body, a needle that opens and closes the nozzle hole is housed, and a back pressure chamber that provides high pressure fuel pressure to the needle as a back pressure is provided,
An orifice plate disposed adjacent to a nozzle end surface which is an end surface on the main body side of the nozzle body,
The orifice plate is provided in an inflow passage through which high pressure fuel flows into the back pressure chamber, an inflow side orifice provided in the inflow passage, an outflow passage through which high pressure fuel flows out from the back pressure chamber, and the outflow passage. An outflow orifice is formed,
A groove is formed in a lower end surface of the orifice plate on the nozzle body, and the high pressure path including the high pressure path and the sensor path including the sensor path are communicated with each other by the groove. The fuel injection valve according to claim 1. Inside the nozzle body, a needle that opens and closes the nozzle hole is housed, and a back pressure chamber that provides high pressure fuel pressure to the needle as a back pressure is provided,
An orifice plate disposed between the nozzle end surface, which is an end surface on the body body side of the nozzle body, and the body end surface;
The orifice plate is provided in an inflow passage through which high pressure fuel flows into the back pressure chamber, an inflow side orifice provided in the inflow passage, an outflow passage through which high pressure fuel flows out from the back pressure chamber, and the outflow passage. An outflow orifice is formed,
A groove is formed on the upper end surface of the orifice plate, which is the end surface on the body body side, and the high pressure path including the high pressure passage and the sensor path including the sensor path are communicated with each other by the groove. The fuel injection valve according to claim 1. An annular passage for annularly distributing the high-pressure fuel flowing out from the outlet of the high-pressure passage;
The fuel injection valve according to any one of claims 1 to 5, wherein an annular groove formed as a part of the annular passage is used as the groove.

Images