JP2014118820A - Fuel injection valve with cylinder internal pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize reliable and stable connection by preventing disconnection and the like by protecting a signal transmitting portion where a sensor capable of detecting a cylinder internal pressure of a combustion chamber and a signal terminal are connected, and to easily execute the connection work, in a fuel injection valve with a cylinder internal pressure sensor.SOLUTION: A valve housing 40 constituting a fuel injection valve 10 is provided with a signal conductor 54 connecting a connection terminal 48 of a sensor 20 and a signal terminal 22, and a connecting portion 52 for connecting a tip of the signal conductor 54 and a basic end of the connection terminal 48 formed thereon. A cover member 56 mounted on an outer peripheral side of the valve housing 40 is provided with a window portion 64 for work opened to face the connecting portion 52 to execute connection work of the signal conductor 54 and the connection terminal 48 through the window portion 64 for work. The window portion 64 for work is closed by a closing member 66 after the completion of the work.

Description

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

  The present invention has been made in consideration of the above-mentioned problems, and prevents disconnection and the like reliably by protecting a signal transmission unit that connects a sensor capable of detecting the in-cylinder pressure of a combustion chamber and a signal terminal. An object of the present invention is to provide a fuel injection valve with an in-cylinder pressure sensor that can realize a stable connection and can easily perform the connection operation.

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 that is disposed in the combustion chamber and has a valve body that switches 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;
A cover member provided on an outer peripheral side of the signal transmission unit and covering the signal transmission unit;
An opening formed on the cover member and opened to face a connection portion between the signal transmission unit and the sensor;
With
The opening is provided with a closing member that closes the opening.

  According to the present invention, by providing a cover member on the outer peripheral side of the signal transmission unit, the signal transmission unit can be protected, disconnection and the like can be prevented, and a reliable and stable connection can be realized. It is possible to easily and reliably perform the connecting operation of the connecting portion from the outside through the opening of the cover member. In addition, after the connection work is completed, it is possible to reliably prevent moisture and the like from entering the inside through the opening from the outside of the fuel injection valve by closing the opening with the closing member.

  Furthermore, the signal transmission unit may be a conducting wire disposed along the axial direction of the valve housing.

  Furthermore, the closing member is composed of a divided body obtained by dividing the cylindrical body along the axial direction. By attaching and connecting to the cover member so as to match the divided bodies, the opening can be easily and reliably formed. It becomes possible to block and prevent entry of moisture and the like from the outside.

  Still further, the split bodies are arranged at positions where their joint surfaces are separated from the opening in the circumferential direction of the cover member. For example, when the joint surfaces are connected to each other by welding or the like, the heat is opened. It is possible to avoid affecting the connection site via the part.

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

  That is, in a fuel injection valve having a sensor at the tip, a signal transmission part for connecting the signal terminal and the sensor is provided on the outer peripheral side of the valve housing, and the outer peripheral side of the signal transmission part is covered with a cover member, An opening is formed in the cover member at a position facing the connection portion between the signal transmission unit and the sensor. Thereby, it is possible to easily and reliably perform the connection work of the connection portion from the outside of the cover member through the opening, and the signal transmission unit is protected by the cover member provided on the outer peripheral side, and disconnection or the like is performed. A reliable and stable connection can be realized. In addition, after the connection work is completed, the opening portion is closed by the closing member, so that moisture or the like can be reliably prevented from entering the inside through the opening portion from the outside of the fuel injection valve.

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 work window part vicinity in the cover member of FIG. FIG. 3 is an enlarged side view showing the vicinity of a work window in FIG. 2. It is a partially exploded perspective view which shows the state which removed the closure member from the 2nd cylinder part of the cover member of FIG.

  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 36 is formed on the base end side (in the direction of arrow A) of the bobbin 32, and the tip ends of the pair of power supply terminals 38 and the signal terminal 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 40 connected to the tip of the solenoid unit 14 and a valve body (not shown) built in the tip of the valve housing 40. 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 40 is formed of, for example, a metal material, and a first flange portion 42 that closes the distal end of the solenoid portion 14 and a straight line from the first flange portion 42 toward the distal end side (arrow B direction). The cylindrical sensor 20 is press-fitted and fitted to the outer peripheral side of the tip of the first cylinder part 44.

  Further, the outer peripheral surfaces of the first flange portion 42 and the first tube portion 44 extend from the proximal end side of the first flange portion 42 toward the distal end side (arrow B direction) of the first tube portion 44. A wiring groove 46 is formed, and a signal conducting wire 54 (described later) constituting the signal transmission unit 24 is accommodated therein.

  The sensor 20 includes, for example, a piezoelectric element (not shown) therein, and a connection terminal 48 connected to the piezoelectric element extends to the base end side (arrow A direction). The connection terminal 48 is covered with an insulator 50 made of, for example, a heat-resistant resin material, and extends to the vicinity of the center of the valve housing 40 along the axial direction of the first tube portion 44, as shown in FIG. As described above, the connection portion 52 formed on the base end side is exposed to the outside and connected to the distal end of the signal conducting wire 54.

  Further, a holding portion 62 of a cover member 56 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 40 by welding all around.

  The signal transmission unit 24 includes a signal conducting wire 54 that electrically connects the signal terminal 22 and the sensor 20, and the tip of the signal transmission unit 24 is connected to the first tube unit 44 of the valve housing 40 as shown in FIGS. 2 and 3. In the space formed between the cover member 56 and the second cylindrical portion 58, the sensor member 20 is connected to the connection portion 52 of the connection terminal 48. On the other hand, as shown in FIG. The end is connected to the tip of the signal terminal 22 inside the coil housing 30. Thereby, the sensor 20 and the signal terminal 22 are electrically connected via the signal conducting wire 54. The leading end of the signal conducting wire 54 extends to the vicinity of the center along the axial direction of the first tube portion 44. A cover member 56 is attached to the outer peripheral side of the valve housing 40 so as to cover the signal transmission unit 24. In addition, since the signal conducting wire 54 is coated on the outside, it is not necessary to insulate it with the insulator 50 or the like, and it may be simply stored in the wiring groove 46 of the valve housing 40.

  The cover member 56 is formed, for example, in a cylindrical shape from a metal material, corresponds to the shape of the valve housing 40, and has a second cylindrical portion 58 formed in a cylindrical shape so as to cover the outer peripheral side of the first cylindrical portion 44. And a second flange portion 60 which is formed on the base end side (in the direction of arrow A) and expands with respect to the second cylindrical portion 58 and covers the outer peripheral side of the first flange portion 42.

  As shown in FIGS. 1 and 2, a holding portion 62 that holds the outer peripheral surface on the proximal end side of the sensor 20 is formed at the distal end of the cover member 56, while the second cylindrical portion 58 has an outer peripheral surface. A working window portion (opening portion) 64 that penetrates to the inside of the second cylindrical portion 58 is formed.

  As shown in FIGS. 2 and 3, the working window portion 64 has a predetermined length along the axial direction (arrow A and B directions) of the second cylindrical portion 58 and a predetermined length along the circumferential direction. It opens in a substantially rectangular shape so as to have a width, is located at a position intermediate between the distal end and the proximal end of the second cylindrical portion 58, and at a position facing the connection portion between the signal conducting wire 54 and the connection portion 52 of the sensor 20. It is formed. That is, as shown in FIG. 2, in a state where the cover member 56 is attached to the valve housing 40, the connection part between the signal conductor 54 and the connection part 52 of the sensor 20 is exposed to the outside through the work window part 64. It will be in the state.

  In addition, a closing member 66 is attached to the second cylindrical portion 58 of the cover member 56 so as to close the working window portion 64. As shown in FIG. 4, the closing member 66 includes, for example, divided bodies 66 a and 66 b obtained by dividing a cylindrical body from a metal material, and the inner peripheral diameter thereof is substantially equal to the outer peripheral diameter of the second cylindrical portion 58. Identical and formed. Then, the work window portion 64 is closed by the closing member 66 by covering the two divided portions 66 a and 66 b with the outer peripheral surface of the second cylindrical portion 58 so as to be in contact therewith.

  The fuel injection valve 10 according to the embodiment of the present invention is basically configured as described above. Next, the signal conductor 54 of the signal transmission unit 24 and the connection terminal 48 of the sensor 20 are connected. The case where it does is demonstrated. The state where the signal conducting wire 54 is disposed on the outer peripheral side of the first cylindrical portion 44 in the valve housing 40 will be described as an initial state.

  First, in this initial state, the cover member 56 is inserted into the outer peripheral side of the valve housing 40, and then the first tube of the valve housing 40 is inserted from the front end side so as to be between the cover member 56 and the valve housing 40. By press-fitting the sensor 20 into the portion 44, the sensor 20 is fitted to a position on the outer peripheral side and the inner peripheral side of the holding portion 62 with respect to the tip of the first cylindrical portion 44. In that case, the connection part of the connection terminal 48 and the signal conductor 54 is arrange | positioned so that the work window part 64 may be faced. That is, the sensor 20 is mounted so that the connection portion between the connection terminal 48 and the signal conductor 54 can be visually recognized from the outside through the work window 64 (see FIG. 3).

  Next, an operator (not shown) is electrically connected by solder or the like with the tip of the signal conductor 54 in contact with the connection portion 52 of the connection terminal 48 from the outside of the cover member 56 through the work window portion 64. Thereby, the connection terminal 48 and the signal conducting wire 54 of the sensor 20 are connected to each other via the connection portion 52, and accordingly, the sensor 20 and the signal terminal 22 are connected.

  Finally, after confirming the connection between the connection terminal 48 of the sensor 20 and the signal conducting wire 54 from the outside of the cover member 56 via the work window 64, as shown in FIG. The work window portion 64 is attached to the outer peripheral surface of the second cylindrical portion 58 so as to be closed by the bodies 66a and 66b (see FIG. 2). Then, in a state where the joining surface 68a (see FIG. 4) of one divided body 66a and the joining surface 68b (see FIG. 4) of the other divided body 66b are in contact with each other, for example, the joining surface 68a is used by a welding device (not shown). , 68b are welded together. Accordingly, the divided parts 66a and 66b are integrally connected as a closing member 66, and are fixed to the cover member 56 in a state where the working window portion 64 is closed. As a result, the working window portion 64 is completely covered and closed by the closing member 66, the inside of the cover member 56 cannot be visually recognized from the outside, and moisture from the outside to the inside of the cover member 56, etc. Intrusion is reliably prevented.

  In this case, the joining surfaces 68 a and 68 b of the closing member 66 are fixed to the cover member 56 at a position offset in the circumferential direction with respect to the work window 64 without facing the work window 64. Accordingly, since the sealing member 66 is welded in a state where the joining surfaces 68a and 68b and the work window 64 are separated from each other by a predetermined distance, the heat generated when welding the joining surfaces 68a and 68b. Is avoided from affecting the internal connection sites.

  As described above, when the working window portion 64 is formed on the outer peripheral surface of the cover member 56 and the cover member 56 is mounted on the outer peripheral side of the valve housing 40, the connection between the connection terminal 48 of the sensor 20 and the signal conductor 54. Even after the outer peripheral side of the valve housing 40 is covered with the cover member 56 by opening it at a position facing the part, the connection work between the connection portion 52 of the connection terminal 48 and the signal conductor 54 is performed from the outside of the cover member 56. It becomes possible to carry out easily and reliably. As a result, by providing the cover member 56 on the outer peripheral side of the signal conducting wire 54 and protecting it, disconnection and the like can be prevented and a reliable and stable connection can be realized, and the connection work through the work window 64 has been completed. Thereafter, the work window 64 is closed by the closing member 66, so that the entry of moisture or the like into the cover member 56 can be reliably prevented, and waterproofness can be ensured.

  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 signal conductor 54 and the signal terminal 22 of the sensor 20, and is used for, for example, combustion control based on the pressure in the combustion chamber.

  Further, the closing member 66 is not limited to the divided bodies 66a and 66b obtained by dividing the cylindrical body into two parts. For example, the closing member 66 may be a sheet-like member formed larger than the work window 64, The work window 64 may be filled. That is, the shape or the like is not particularly limited as long as the work window 64 can be reliably closed after the connection work is completed and the intrusion of moisture or the like from the outside can be prevented.

  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 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 38 ... Feed terminal 40 ... Valve housing 48 ... Connection terminal DESCRIPTION OF SYMBOLS 50 ... Insulator 52 ... Connection part 54 ... Signal conducting wire 56 ... Cover member 64 ... Working window part 66 ... Closure member

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 that is disposed in the combustion chamber and has a valve body that switches 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;
A cover member provided on an outer peripheral side of the signal transmission unit and covering the signal transmission unit;
An opening formed on the cover member and opened to face a connection portion between the signal transmission unit and the sensor;
With
A fuel injection valve with an in-cylinder pressure sensor, wherein a closing member that closes the opening is attached to the opening. The fuel injection valve according to claim 1, wherein
The fuel injection valve with an in-cylinder pressure sensor, wherein the signal transmission unit is a conducting wire disposed along the axial direction of the valve housing. The fuel injection valve according to claim 1 or 2,
The closing member comprises a divided body obtained by dividing a cylindrical body along an axial direction, and is mounted and connected to the cover member so as to match the divided bodies. . The fuel injection valve according to claim 3, wherein
The fuel injection valve with an in-cylinder pressure sensor, wherein the divided bodies are arranged at positions where their joint surfaces are separated from the opening in the circumferential direction of the cover member.

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