JP6002565B2 - Fuel injection valve with in-cylinder pressure sensor - Google Patents

Description

  The present invention relates to a fuel injection valve with an in-cylinder pressure sensor that is used in a direct injection type internal combustion engine that directly injects into a combustion chamber of the internal combustion engine and has a sensor capable of detecting the in-cylinder pressure in the combustion chamber.

  2. Description of the Related Art Conventionally, an internal pressure sensor is known at the tip of a fuel injection valve for the purpose of detecting the in-cylinder pressure of a combustion chamber in an internal combustion engine. This internal pressure sensor is disposed between the tip of the fuel injection valve and the mounting hole of the cylinder head constituting the internal combustion engine. The internal pressure sensor has a lead wire for transmitting the detected in-cylinder pressure as an output signal to the outside. Is connected. The lead wire is connected to, for example, an electronic control unit, and the in-cylinder pressure is output to the electronic control unit as an output signal, whereby control based on the in-cylinder pressure is performed (see, for example, Patent Document 1). ).

JP-A-9-53483

  However, in the internal pressure sensor attached to the fuel injection valve described above, the lead wire connecting the internal pressure sensor and the electronic control unit is exposed to the outside of the fuel injection valve. When assembled to the cylinder head together with the injection valve or in the assembled state, the lead wire may be disconnected due to a load, and there is a concern that the in-cylinder pressure cannot be detected due to the disconnection. Further, the connecting work of electrically connecting the lead wire to the internal pressure sensor and connecting the lead wire to the output terminal connected to the electronic control unit is complicated.

  The present invention has been made in consideration of the above-mentioned problems, and a stable connection state can always be obtained by easily and reliably connecting a sensor capable of detecting the in-cylinder pressure of a combustion chamber and a signal terminal. Another object of the present invention is to provide a fuel injection valve with an in-cylinder pressure sensor capable of enhancing waterproofness.

In order to achieve the above object, the present invention provides a fuel with an in-cylinder pressure sensor having a sensor for detecting the in-cylinder pressure in the combustion chamber at the end of a fuel injection valve that directly injects fuel into the combustion chamber of the internal combustion engine. In the injection valve,
A valve housing disposed inside the combustion chamber and having a valve body for switching an injection state of the fuel;
A sensor attached to the tip of the valve housing;
A signal transmission unit that is provided on the outer peripheral side of the valve housing and connects the sensor to a signal terminal that outputs a signal based on the in-cylinder pressure to the outside ;
With
The signal transmission unit is covered with a cover member, a solenoid unit that generates a driving force for displacing the valve body,
The connection portion of the signal transmission portion with the sensor has a groove portion formed in an annular shape facing the space closed by the cover member, and the signal transmission portion and the sensor via the solder provided in the groove portion. The sensor connection portion is electrically connected.

  According to the present invention, a conventional fuel injection valve in which a signal transmission unit that connects a sensor and a signal terminal is provided inside the cover member, and thus the wiring connected to the sensor is arranged outside the fuel injection valve. Compared to the above, since it is possible to prevent a load such as a tensile force from being applied to the signal transmission unit, it is possible to reliably prevent occurrence of disconnection due to the load. As a result, the cylinder pressure in the combustion chamber detected by the sensor can be reliably and stably output to the signal terminal as an output signal. Even if the connection part between the sensor and the signal terminal is covered by the cover member, the solder provided in the groove can be reliably and easily connected by heating and melting the solder from the outside. Further, by providing the signal transmission part inside the cover member so as not to be exposed to the outside, even if moisture etc. exists outside the fuel injection valve, the moisture etc. to the signal transmission part side Since the intrusion is prevented, the short circuit is surely prevented by the improvement of waterproofness.

  Furthermore, the signal transmission part has a conductive layer formed in a cylindrical shape, and the solder provided in the groove part is melted by disposing the end part of the conductive layer so as to be exposed to the sensor side in the groove part. In this case, it is possible to easily and reliably cover and electrically connect the conductive layer and the connection portion of the sensor with the solder.

  Still further, the groove portion may be formed at an end portion of an insulator formed of a resin material.

  Further, a part of the cover member covers the outer peripheral surface of the sensor so that it is covered with the cover member, and it is possible to more reliably prevent moisture and the like from entering the internal space in which the signal transmission unit is housed. Can be increased.

  According to the present invention, the following effects can be obtained.

  That is, in the fuel injection valve having a sensor at the tip, by providing a signal transmission part that connects the signal terminal and the sensor on the outer peripheral side of the valve housing, and covering the outer peripheral side of the signal transmission part with a cover member, Compared with the conventional fuel injection valve in which the wiring connected to the sensor is arranged outside the fuel injection valve, it is possible to prevent load from being applied to the signal transmission unit and to reliably prevent the occurrence of disconnection. As a result, the in-cylinder pressure in the combustion chamber detected by the sensor can be reliably and stably output to the signal terminal as an output signal. In addition, since the signal transmission part has an annular groove part facing the connection part of the sensor and the space closed by the cover member, the signal transmission part is blocked by the cover member by melting the groove part by providing solder. It is possible to easily and reliably connect the connection part of the sensor and the signal transmission part even in the space formed. Furthermore, since the signal transmission unit is covered with the cover member and is not exposed to the outside, the waterproofness can be improved by preventing the entry of moisture or the like from the outside to the signal transmission unit side.

It is a partial cross section front view of the fuel injection valve with a cylinder pressure sensor which concerns on embodiment of this invention. It is an expanded sectional view which shows the sensor vicinity in the fuel injection valve with a cylinder pressure sensor of FIG. It is an expanded sectional view which shows the state in the middle of the assembly | attachment before the 1st signal transmission member and sensor in FIG. 2 are electrically connected by solder.

  The fuel injection valve with an in-cylinder pressure sensor according to the present invention will be described in detail below with reference to the accompanying drawings by giving preferred embodiments. In FIG. 1, reference numeral 10 indicates a fuel injection valve with an in-cylinder pressure sensor according to an embodiment of the present invention.

  As shown in FIG. 1, the fuel injection valve 10 with an in-cylinder pressure sensor (hereinafter simply referred to as a fuel injection valve 10) includes a housing 12, a solenoid portion 14 provided at the front end of the housing 12, and the solenoid portion 14. A fuel injection section 16 provided at the distal end of the housing 12, a fuel supply section 18 provided at the proximal end of the housing 12 to which fuel is supplied, a sensor 20 attached to the distal end of the fuel injection section 16, and an electronic control (not shown) A signal transmission unit 24 that electrically connects a signal terminal 22 connected to a unit (ECU) and the sensor 20 to transmit an output signal is included. Hereinafter, the fuel supply unit 18 side of the fuel injection valve 10 will be described as the base end side (arrow A direction), and the fuel injection unit 16 side will be described as the front end side (arrow B direction).

  The housing 12 includes a main body portion 26 and a coupler 28 protruding laterally from the base end of the main body portion 26, and the fuel supply portion 18 is provided at the base end of the main body portion 26. The fuel supply unit 18 includes, for example, a supply passage (not shown) through which fuel is supplied, and supplies the fuel supplied through a fuel pipe (not shown) from the supply passage to the fuel injection unit 16 side. Further, a connector (not shown) connected to an electronic control unit (not shown) is detachably attached to the coupler 28.

  The solenoid unit 14 is a cylindrical coil housing 30, a bobbin 32 accommodated in the coil housing 30, a coil 34 wound around the bobbin 32, and a movable member that is displaced under the excitation action of the coil 34. A core (not shown), and a proximal end of the coil housing 30 is connected to a distal end of the housing 12. A terminal support portion 36 is formed on the proximal end side of the bobbin 32, and the distal ends of the pair of power supply terminals 38 and the signal terminals 22 are held. Thereby, the power supply terminal 38 is electrically connected to the coil 34 via the terminal support portion 36. On the other hand, the proximal end sides of the power supply terminal 38 and the signal terminal 22 protrude from the inner wall surface inside the coupler 28, and a part thereof is exposed to the outside.

  Then, by connecting a connector (not shown) to the coupler 28, each power supply terminal 38 and the signal terminal 22 are connected to the electronic control unit, and when the power supply terminal 38 is energized from the electronic control unit, the coil 34 is connected. Magnetic force is generated by excitation. As a result, the movable core is displaced inside the bobbin 32 under the excitation action of the coil 34, and a valve body (not shown) provided in the fuel injection section 16 is sucked and opened.

  The fuel injection unit 16 includes a valve housing 42 connected to the tip of the solenoid unit 14 and a valve body (not shown) built in the tip of the valve housing 42. Fuel is supplied from the supply unit 18, and the valve body moves toward the base end side (in the direction of arrow A) under the excitation action of the solenoid unit 14, whereby the fuel is injected from the tip into the combustion chamber at a predetermined pressure.

  The valve housing 42 is made of, for example, a metal material, and a flange portion 44 that closes the distal end of the solenoid portion 14 and a cylinder that extends straight from the flange portion 44 toward the distal end side (arrow B direction). The cylindrical sensor 20 is press-fitted and fitted to the outer peripheral side of the end of the cylindrical portion 46.

  The sensor 20 includes, for example, a piezoelectric element (not shown) therein, and a connection terminal (connection portion) 48 connected to the piezoelectric element is exposed on the base end side (arrow A direction).

  Further, a holding portion 68 of a cover member 62 to be described later contacts the outer peripheral surface of the sensor 20.

  For example, the inner peripheral side of the tip of the sensor 20 is coupled to the valve housing 42 by welding all around.

  The signal transmission unit 24 is provided on the outer peripheral side of the valve housing 42 and is housed in the first signal transmission member 54 connected to the sensor 20 and the coil housing 30 of the solenoid unit 14. 2nd signal transmission member 56 which connects signal terminal 22 is included.

  The first signal transmission member 54 is formed, for example, in a cylindrical shape from a resin material, and an insulator 58 provided on the outer peripheral side of the cylindrical portion 46 in the valve housing 42 and a first conductive provided in the insulator 58. Layer 60. A cover member 62 is attached to the outer peripheral side of the insulator 58 to cover the insulator 58. The insulator 58 is formed of, for example, a resin material such as a heat-resistant resin, and the base end side (the direction of the arrow A) is expanded so as to cover the cylindrical portion 46 and the flange portion 44 corresponding to the shape of the valve housing 42. Formed. A first conductive layer 60 is formed at the center of the insulator 58 in the radial direction. The first conductive layer 60 is made of, for example, a plating layer, and has a substantially constant thickness on the insulator 58. A cylindrical shape is formed along.

  The tip of the insulator 58 is press-fitted into the sensor 20 together with the cylindrical portion 46 of the valve housing 42, and an annular groove (groove) 64 that is recessed radially inward is formed on the outer peripheral surface near the tip. The annular groove 64 is formed in, for example, a rectangular cross section, and a wall surface 64a on the distal end side (in the direction of arrow B) is formed to be recessed toward the distal end side (in the direction of arrow B) with respect to the base end of the sensor 20, while A wall surface 64b on the base end side (in the direction of arrow A) in the groove 64 is formed at a position on the solenoid portion 14 side by a predetermined distance from the base end of the sensor 20.

  In addition, the annular groove 64 is provided with a U-shaped cross section so that the tip of the first conductive layer 60 is exposed along the wall surface, and for example, a ring-shaped solder 66 is provided therein.

  The cover member 62 is formed, for example, in a cylindrical shape from a metal material, and the base end side (in the direction of the arrow A) is expanded so as to cover the cylindrical portion 46 and the flange portion 44 corresponding to the shape of the valve housing 42. It is formed. A holding portion 68 that holds the outer peripheral surface of the base end side of the sensor 20 is formed at the distal end of the cover member 62, and an annular space 70 is formed between the holding portion 68 and the insulator 58. . Then, the solder 66 provided in the annular groove 64 facing the space 70 is melted by heating from the outside of the cover member 62 and the inside of the annular groove 64 where the first conductive layer 60 is exposed and the connection terminal 48 are exposed. It flows so as to cover the spot, and solidifies by being cooled (see FIG. 2). Thereby, the connection terminal 48 of the sensor 20 is electrically connected to the first conductive layer 60 of the first signal transmission member 54 via the solder 66.

  The second signal transmission member 56 is made of, for example, a resin material, has a plate shape having a predetermined length along the axial direction (arrows A and B directions), and is formed of a material that can be energized therein. The second conductive layer 72 is formed. The second conductive layer 72 is formed of, for example, a plated layer, and extends from the distal end to the proximal end along the axial direction (arrow A and B directions) of the second signal transmission member 56 with a substantially constant thickness. .

  The distal end of the second signal transmission member 56 has a first connecting portion 74 having a small diameter reduced with respect to the proximal end side. The first connecting portion 74 has a second conductive layer along the outer peripheral surface thereof. A part of 72 is exposed in an annular shape. Then, the first connection portion 74 is inserted into a connection hole formed at the base end of the first signal transmission member 54 and electrically connected by solder or the like, so that the sensor 20 is connected via the first signal transmission member 54. And the second signal transmission member 56 are electrically connected.

  On the other hand, a second connection portion 76 protruding in a direction orthogonal to the axis is formed at the base end of the second signal transmission member 56, one end of which abuts on the tip of the signal terminal 22, and the other end is a coil housing. It is provided so as to contact the inner peripheral surface of 30. The second connection portion 76 is formed in a cylindrical shape having a through-hole inside, and is provided so that the base end side of the second conductive layer 72 is exposed on the side surface facing the signal terminal 22. Then, one end portion of the second connection portion 76 is electrically connected by solder or the like in a state where it abuts on the signal terminal 22 via the second conductive layer 72. Thereby, the sensor 20 and the signal terminal 22 are electrically connected to each other via the first and second signal transmission members 54 and 56.

  The fuel injection valve 10 according to the embodiment of the present invention is basically configured as described above. Next, the case where the fuel injection valve 10 is assembled will be described. The state in which the first signal transmission member 54 is assembled in advance on the outer peripheral side of the valve housing 42 will be described as an initial state.

  First, in this initial state, a ring-shaped solder 66 is inserted into an annular groove 64 formed at the distal end of the insulator 58, placed in the annular groove 64, and then covered from the distal end side of the insulator 58. 62 is inserted toward the base end side. Then, as shown in FIG. 3, the first signal transmission member 54 is covered by attaching the cover member 62 so as to cover the flange portion 44 and the cylindrical portion 46 of the valve housing 42, and the holding portion 68 supports the first signal transmission member 54. The outer circumferential side of the annular groove 64 and the solder 66 is covered.

  Next, the sensor 20 is press-fitted into the cylindrical portion 46 of the valve housing 42 from the front end side so as to be between the cover member 62 and the valve housing 42, so that the sensor 20 is The insulator 58 is fitted at a position on the outer peripheral side with respect to the tip of the insulator 58 and on the inner peripheral side of the holding portion 68. As a result, a space 70 closed by the insulator 58, the holding portion 68 of the cover member 62 and the base end of the sensor 20 is formed, and the solder 66 is disposed in the space 70 via the annular groove 64. . The inner peripheral side of the tip end of the sensor 20 is integrally fixed by welding to the tip end of the valve housing 42.

  Finally, a heating device (for example, a laser irradiator) (not shown) is disposed on the outer peripheral side of the holding portion 68, and heat is applied to the solder 66 from the outside of the cover member 62 by the heating device (see arrow H in FIG. 2). The solder 66 melts and flows in the space 70. The solder 66 that has flowed moves so as to cover the annular groove 64 and the connection terminal 48 and is cooled to solidify in a state where the annular groove 64 and the connection terminal 48 are filled (see FIG. 2). As a result, the first conductive layer 60 provided in the annular groove 64 and the connection terminal 48 are electrically connected by the solder 66, and accordingly, the tip of the first signal transmission member 54 and the sensor 20 are electrically connected. Connected. In this case, the base end of the first signal transmission member 54 is electrically connected to the first connection portion 74 of the second signal transmission member 56 in advance.

  Next, the operation of the fuel injection valve 10 assembled as described above will be briefly described.

  During operation of the internal combustion engine, the coil 34 is energized from the power supply terminal 38 of the fuel injection valve 10 by a control signal from an electronic control unit (not shown), and the coil 34 is excited to open the valve body of the fuel injection unit 16. The high-pressure fuel supplied to the supply passage of the fuel supply unit 18 is directly injected into the combustion chamber of the internal combustion engine via the fuel injection unit 16. At this time, the sensor 20 is given a pressure (in-cylinder pressure) in the combustion chamber, so that the piezoelectric element generates a voltage according to the pressure and outputs it as an output signal. This output signal is output to the electronic control unit via the connection terminal 48, the first signal transmission member 54, the second signal transmission member 56, and the signal terminal 22, for example, for combustion control based on the pressure in the combustion chamber. Used.

  As described above, in the present embodiment, in the fuel injection valve 10 having the sensor 20 at the tip thereof, the first and second signal transmission members 54 of the signal transmission unit 24 that connects the sensor 20 and the signal terminal 22. , 56 are arranged inside the cover member 62 and the coil housing 30, compared with the fuel injection valve according to the prior art in which the lead wire connected to the internal pressure sensor is arranged outside, the signal transmission unit 24 is The application of a load such as pulling can be prevented, and the occurrence of disconnection due to the load can be prevented. As a result, the pressure in the combustion chamber detected by the sensor 20 can be reliably transmitted as an output signal to the signal terminal 22 through the first and second signal transmission members 54 and 56 and output to the electronic control unit. Become.

  In addition, after the connection terminal 48 of the sensor 20 and the distal end side of the first signal transmission member 54 are covered by the cover member 62, the solder 66 is inserted into the annular groove 64 at the distal end of the insulator 58 provided with the first conductive layer 60. And the solder 66 is melted by heating from the outside of the cover member 62 so that the connection terminal 48 of the sensor 20 and the first conductive layer 60 of the first signal transmission member 54 are easily electrically connected. Can be connected to. That is, even after the joint portion between the sensor 20 and the first signal transmission member 54 is covered with the cover member 62, the joint portion can be easily and reliably connected by the solder 66 by heating from the outside.

  Furthermore, the first and second signal transmission members 54 and 56 constituting the signal transmission unit 24 are housed inside the cover member 62 and the coil housing 30 and are not exposed to the outside. Even when moisture or the like is present, adhesion of the moisture or the like to the signal transmission unit 24 is prevented, and a short circuit can be reliably prevented. In other words, by providing the cover member 62, it is possible to improve the waterproofness of the signal transmission unit 24 in the fuel injection valve 10.

  Furthermore, since the solder 66 for connecting the first signal transmission member 54 and the sensor 20 can be installed in advance in the annular groove 64 of the insulator 58, the solder 66 is always melted at the same position. Can be connected. Therefore, there is no variation in the connection position between the first signal transmission member 54 and the sensor 20, and a stable connection can be realized. Furthermore, since the amount of the solder 66 can be managed easily and accurately, a stable connection can be realized without variation in the connection state between the first signal transmission member 54 and the sensor 20.

  Further, for example, the solder 66 is formed in a ring shape and placed in the annular groove 64, so that the solder 66 can be easily installed and the usage amount of the solder 66 can be accurately managed.

  Further, since the first conductive layer 60 is formed in a cylindrical shape along the circumferential direction of the insulator 58, the connection terminal 48 of the sensor 20 is connected when the sensor 20 and the first signal transmission member 54 are connected. However, it is not necessary to position the insulator 58 (first conductive layer 60) in the circumferential direction, and the first conductive layer 60 can be connected to the sensor 20 at any position in the circumferential direction. Therefore, when connecting an internal pressure sensor and a lead wire, the assembly workability | operativity can be improved compared with the fuel injection valve of the prior art which needs to perform alignment of the circumferential direction previously.

  In addition, the fuel injection valve with an in-cylinder pressure sensor according to the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Fuel injection valve with in-cylinder pressure sensor 12 ... Housing 14 ... Solenoid part 16 ... Fuel injection part 18 ... Fuel supply part 20 ... Sensor 22 ... Signal terminal 24 ... Signal transmission part 30 ... Coil housing 42 ... Valve housing 48 ... Connection terminal 54 ... First signal transmission member 56 ... Second signal transmission member 58 ... Insulator 60 ... First conductive layer 62 ... Cover member 64 ... Annular groove 66 ... Solder 72 ... Second conductive layer

Claims (4)

In a fuel injection valve with an in-cylinder pressure sensor having a sensor for detecting the in-cylinder pressure in the combustion chamber at the end of the fuel injection valve that directly injects fuel into the combustion chamber of the internal combustion engine,
A valve housing disposed inside the combustion chamber and having a valve body for switching an injection state of the fuel;
A sensor attached to the tip of the valve housing;
A signal transmission unit that is provided on the outer peripheral side of the valve housing and connects the sensor to a signal terminal that outputs a signal based on the in-cylinder pressure to the outside ;
With
The signal transmission unit is covered with a cover member, a solenoid unit that generates a driving force for displacing the valve body,
The connection portion of the signal transmission portion with the sensor has a groove portion formed in an annular shape facing the space closed by the cover member, and the signal transmission portion and the sensor via the solder provided in the groove portion. A fuel injection valve with an in-cylinder pressure sensor, wherein a connection portion of the sensor is electrically connected. The fuel injection valve according to claim 1, wherein
The fuel transmission valve with an in-cylinder pressure sensor, wherein the signal transmission unit includes a conductive layer formed in a cylindrical shape, and an end of the conductive layer is disposed to be exposed to the sensor side in the groove. . The fuel injection valve according to claim 1 or 2,
The said groove part is formed in the edge part of the insulator formed from the resin-made materials, The fuel injection valve with a cylinder internal pressure sensor characterized by the above-mentioned. The fuel injection valve according to any one of claims 1 to 3,
A fuel injection valve with an in-cylinder pressure sensor, wherein a part of the cover member covers an outer peripheral surface of the sensor.

Images