JP2016133069A - Fuel injection valve with cylinder pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve with a cylinder pressure sensor for improving detecting accuracy in a compact configuration.SOLUTION: A signal transmission part 24 constituting a fuel injection valve 10 has an amplification circuit 58 between a first signal transmission member 54 provided on the front end side and a sensor 20 for amplifying and outputting a detection signal detected by the sensor 20. A first conductive layer 62 provided inside the first signal transmission member 54 consists of first power supply layers 64a, 64b for supplying power to the sensor 20, and a first output transmission layer 66 for transmitting the detection signal from the sensor 20. The first power supply layers 64a, 64b and the first output transmission layer 66 are electrically connected at their front ends through the amplification circuit 58 to the sensor 20.SELECTED DRAWING: Figure 2

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 that constitutes the internal combustion engine. The internal pressure sensor has a lead wire for transmitting the detected in-cylinder pressure to the outside as a detection signal. 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 a detection signal, thereby performing control based on the in-cylinder pressure (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. Therefore, for example, when the internal pressure sensor is assembled to the cylinder head together with the fuel injection valve or in the assembled state, there is a risk of disconnection due to a load applied to the lead wire, and the in-cylinder pressure cannot be detected due to the disconnection. Concerned.

  In order to avoid the risk of disconnection or the like described above, for example, it is conceivable to store the lead wire inside the fuel injection valve. However, the outer diameter of the fuel injection valve is increased by the amount of the lead wire. It will end up.

  Furthermore, since the internal pressure sensor is disposed in contact with the cylinder head, for example, noise due to vibration of the internal combustion engine or the like is likely to be generated, and the detection value detected by the internal pressure sensor can be read with high accuracy. There is a problem that it is difficult.

  The present invention has been made in consideration of the above-described problems, and an object of the present invention is to provide a fuel injection valve with an in-cylinder pressure sensor capable of improving detection accuracy with a compact structure.

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 signal transmission member that transmits the in-cylinder pressure detected by the sensor as a detection signal;
The signal transmission member includes a first transmission unit connected to the sensor;
A second transmission unit connected to the first transmission unit and outputting a detection signal to the outside;
An amplification circuit provided in the first transmission unit and directly connected to the sensor to amplify the detection signal;
With
The power supply means for supplying power to the amplifier circuit is a circuit layer provided on the signal transmission member.

  According to the present invention, a fuel injection valve with an in-cylinder pressure sensor having a sensor for detecting an in-cylinder pressure in a combustion chamber includes a signal transmission member that transmits the in-cylinder pressure detected by the sensor as a detection signal, and is directly connected to the sensor. An amplifier circuit for amplifying the detection signal is provided in the first transmission unit, and power supply means for supplying power to the amplifier circuit is a circuit layer provided in the signal transmission member.

  Therefore, the power supply means is configured in the circuit layer and connected to the amplifier circuit, so that the signal transmission member does not increase in size in the radial direction as compared with the case where it is connected by a lead wire or the like, and includes the signal transmission member. The fuel injection valve has a compact structure, and when noise due to vibrations of the internal combustion engine occurs, amplifying circuit directly connected to the sensor suitably amplifies the detection signal with very little noise near the sensor. Therefore, the detection accuracy can be improved.

  The signal output means for outputting the detection signal amplified by the amplifier circuit may be a circuit layer provided on the signal transmission member.

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

  That is, a fuel injection valve with an in-cylinder pressure sensor having a sensor for detecting the in-cylinder pressure in the combustion chamber includes a signal transmission member that transmits the in-cylinder pressure detected by the sensor as a detection signal, and is directly connected to the sensor to transmit the detection signal. Amplifying circuit for amplifying is provided in the first transmission unit, and the power supply means for supplying power to the amplifying circuit is a circuit layer provided in the signal transmission member, thereby comparing with the case of connecting by lead wires or the like, The signal transmission member can be reduced in the radial direction, and accordingly, the fuel injection valve including the signal transmission member can have a compact structure. In addition, by directly connecting an amplifier circuit to the sensor, it is possible to suitably amplify a detection signal with very little noise near the sensor, so that it is possible to improve detection accuracy.

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 a side view from the coupler part side which shows the state before forming the resin mold part of the fuel injection valve with a cylinder pressure sensor of FIG. FIG. 3 is an enlarged side view showing the vicinity of a first signal transmission member in FIG. 2.

  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 a cylinder pressure sensor (hereinafter simply referred to as a fuel injection valve 10) includes a housing 12, a resin mold portion 14 provided on the outer peripheral side of the housing 12, and the housing 12, a fuel supply unit 16 that is supplied with fuel, a fuel injection unit 18 that is provided at the front end of the housing 12, a sensor 20 that is attached to the front end of the fuel injection unit 18, and an electronic device (not shown). A signal terminal (second transmission unit) 22 connected to a control unit (ECU) and a signal transmission unit (first transmission unit) 24 that electrically connects the sensor 20 and transmits a detection signal are included.

  Hereinafter, as shown in FIG. 1, the fuel supply unit 16 side of the fuel injection valve 10 is described as a base end side (arrow A direction), and the fuel injection unit 18 side is described as a front end side (arrow B direction).

  The housing 12 is configured as a solenoid unit that drives the fuel injection valve 10, and includes a fixed core 26 provided at the center thereof, a bobbin 30 provided on the outer peripheral side of the fixed core 26 and holding a coil 28, Furthermore, it has a cylindrical holder 32 provided on the outer peripheral side of the tip, and a movable core (not shown) that is displaced under the exciting action of the coil 28.

  The fixed core 26 further extends toward the base end side (arrow A direction) of the housing 12 with respect to the base end of the holder 32, and is disposed at the center of the resin mold portion 14 to be described later. An annular first groove portion 34 to be engaged with a resin mold portion 14 to be described later is formed. A fuel supply unit 16 is provided on the base end side of the fixed core 26.

  The bobbin 30 is, for example, cylindrical and is provided between the fixed core 26 and the holder 32, and a coil 28 is wound on the outer peripheral side of the bobbin 30 via a concave portion recessed radially inward. A second signal transmission member 56 of a signal transmission unit (signal transmission member) 24 described later is provided on the side.

  The end portions of the coils 28 extend toward the base end side (in the direction of arrow A) of the bobbin 30 and are respectively connected to the end portions of the pair of drive terminals 36, and from the connectors not shown to the coil 28 through the drive terminals 36. Is energized to generate magnetic force. As a result, the movable core is displaced inside the bobbin 30 under the exciting action of the coil 28 in the housing 12, and a valve body (not shown) provided in the fuel injection unit 18 is sucked and opened.

  An annular second groove 38 that is recessed radially inward is formed on the outer peripheral surface of the base end of the holder 32, and a resin mold portion 14 to be described later is engaged therewith.

  The resin mold part 14 is formed on the outer peripheral side of the housing 12 by molding from a resin material, for example, and a main body part 40 formed in a cylindrical shape, and a coupler part 42 protruding sideways from the base end of the main body part 40. And a connecting portion 44 for connecting the main body portion 40 and the coupler portion 42. Then, by molding the resin mold portion 14 with a resin material, the first groove portion 34 of the fixed core 26 provided in the center of the main body portion 40 and the first of the holder 32 provided on the distal end side of the main body portion 40. The melted resin material enters the two groove portions 38, and the housing 12 is fixed to the center and the tip of the resin mold portion 14.

  The coupler part 42 is formed in, for example, a rectangular cross section and protrudes obliquely upward so as to be inclined by a predetermined angle with respect to the axial direction (arrow A, B direction) of the main body part 40. The coupler unit 42 has an open end and a space inside. The power source terminal 46 and the signal terminal 22 connected to the signal transmission unit 24 and a pair of drive terminals for energizing the coil 28. 36 are exposed to each other.

  Then, by connecting a connector (not shown) to the coupler portion 42, power is supplied to the coil 28 of the housing 12 through the drive terminal 36, and the sensor 20 is energized through the power terminal 46 and detected by the sensor 20. The detected value is output as an electrical signal from the signal terminal 22 through the signal transmission unit 24.

  As shown in FIG. 1, the fuel supply unit 16 has, for example, a supply passage (not shown) through which fuel is supplied inside the fixed core 26, and the base end side (in the direction of arrow A) of the fuel injection valve 10. A fuel pipe (not shown) is connected to the end of the supply passage that is open at (). Then, the fuel supplied through the fuel pipe is supplied to the fuel injection unit 18 side (in the direction of arrow B) provided on the tip side through the supply passage.

  The fuel injection unit 18 includes a valve housing 48 connected to the front end of the housing 12 and a valve body (not shown) built in the front end of the valve housing 48. Then, fuel is supplied from the fuel supply unit 16 to the inside of the valve housing 48, and the valve body moves toward the base end side (in the direction of arrow A) under the exciting action of the coil 28, so that the fuel is pressurized from the front end to a predetermined pressure. Is injected into the combustion chamber.

  The valve housing 48 is made of, for example, a metal material and has a flange portion 50 that closes the front end of the housing 12 and a cylindrical portion that extends straight from the flange portion 50 toward the front end side (in the direction of arrow B). The cylindrical sensor 20 is press-fitted and fitted to the outer peripheral side of the end of the cylindrical portion 52.

  The sensor 20 includes, for example, a piezoelectric element (not shown) therein, and a connection terminal connected to the piezoelectric element is exposed on the base end side (arrow A direction). Further, a holding portion of a cover member 68 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 48 by welding all around.

  The signal transmission unit 24 is provided on the outer peripheral side of the valve housing 48, and is housed in the first signal transmission member 54 connected to the sensor 20 and the holder 32 of the housing 12, and the first signal transmission member 54 and the signal terminal 22, a second signal transmission member 56 that connects to the first signal transmission member 22, and an amplification circuit 58 provided between the first signal transmission member 54 and the sensor 20. That is, the amplifier circuit 58 is provided at the tip of the first signal transmission member 54.

  As shown in FIGS. 1 to 3, the first signal transmission member 54 is formed in a cylindrical shape from a resin material, for example, and the insulator 60 provided on the outer peripheral side of the cylindrical portion 52 in the valve housing 48, And a first conductive layer 62 provided inside the insulator 60.

  The insulator 60 is formed of a resin material such as a heat-resistant resin, for example, and the base end side (in the direction of arrow A) is enlarged so as to cover the cylindrical portion 52 and the flange portion 50 corresponding to the shape of the valve housing 48. Formed. In the center of the thickness of the insulator 60 along the radial direction, a first conductive layer 62 made of, for example, a plating layer is formed. The first conductive layer 62 has a substantially constant thickness on the insulator 60. A pair of first power supply layers (power supply means) 64 a and 64 b that extend in the axial direction along the axis and are connected to the power terminal 46 via the second signal transmission member 56, and the second signal transmission member 56 The first output transmission layer (signal output means) 66 is connected to the signal terminal 22 via the.

  The first output transmission layer 66 is provided between one first power supply layer 64a and the other first power supply layer 64b.

  The tip of the insulator 60 is connected to the amplifier circuit 58, and the tips of the first power supply layers 64a and 64b and the first output transmission layer 66 are respectively connected to the substrate (not shown) of the amplifier circuit 58. Electrically connected.

  On the other hand, on the outer peripheral side of the insulator 60, for example, a cover member 68 formed in a cylindrical shape from a metal material is mounted so as to cover the insulator 60, and the cover member 68 has the shape of the valve housing 48. Correspondingly, the base end side (in the direction of arrow A) is formed to have a larger diameter so as to cover the cylindrical portion 52 and the flange portion 50. A holding portion (not shown) 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 68.

  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 70 thus formed is formed.

  The second conductive layer 70 is formed of, for example, a plating layer, and a pair of second power supply layers 72a and 72b connected to the first power supply layers 64a and 64b of the first signal transmission member 54, and a first output transmission. The second output transmission layer 74 is connected to the layer 66.

  A first connecting portion 76 is formed at the tip of the second signal transmission member 56, and the tips of the second power supply layers 72 a and 72 b and the second output transmission layer 74 are exposed, and the base of the first signal transmission member 54 is exposed. The first power supply layers 64a and 64b and the first output transmission layer 66 exposed at the ends are electrically connected by soldering or the like.

  On the other hand, the second connection part 78 is formed at the base end of the second signal transmission member 56, and the base ends of the second power supply layers 72 a and 72 b and the second output transmission layer 74 are exposed to expose the power supply terminal 46 and the signal terminal. 22 are electrically connected to each other by solder or the like. Thereby, the sensor 20, the power supply terminal 46, and the signal terminal 22 are electrically connected to each other via the first and second signal transmission members 54 and 56 constituting the signal transmission unit 24.

  For example, the amplifier circuit 58 has a substrate inside and is formed in a cylindrical shape so as to cover the distal end of the valve housing 48. The distal end of the amplifier circuit 58 is electrically connected to the connection end of the sensor 20. Are electrically connected to the first conductive layer 62 of the first signal transmission member 54, so that the second power supply layers 72 a and 72 b and the first signal transmission member 54 of the second signal transmission member 56 are connected to the first signal transmission member 54. The sensor 20 is energized through the first power supply layers 64a and 64b. On the other hand, after the detection value (detection signal) detected by the sensor 20 is amplified by the amplifier circuit 58, the first signal transmission member 54 is supplied. The signal is output from the signal terminal 22 to the outside through the first output transmission layer 66 and the second output transmission layer 74 of the second signal transmission member 56.

  The in-cylinder pressure sensor-equipped fuel injection valve 10 according to the embodiment of the present invention is basically configured as described above. Next, the operation and effects thereof will be described.

  During operation of the internal combustion engine (not shown), the coil 28 is energized from the power supply terminal 46 of the fuel injection valve 10 by a control signal from the electronic control unit, and the valve body of the fuel injection unit 18 is opened by exciting the coil 28. The high-pressure fuel supplied to the supply passage of the fuel supply unit 16 is directly injected into the combustion chamber of the internal combustion engine via the fuel injection unit 18. At this time, the sensor 20 is applied with a pressure (in-cylinder pressure) in the combustion chamber, so that the piezoelectric element generates a voltage corresponding to the pressure and outputs it as a detection signal.

  This detection signal is amplified by being output from the sensor 20 to the amplification circuit 58, and then output from the signal terminal 22 to the electronic control unit via the first signal transmission member 54 and the second signal transmission member 56. .

  For example, in the electronic control unit, the pressure in the combustion chamber is calculated from the amplified detection signal, and is used for combustion control based on the pressure.

  As described above, in the present embodiment, the signal transmission unit 24 that can transmit the detection signal detected by the sensor 20 is provided, and the amplifier circuit 58 is provided between the first signal transmission member 54 and the sensor 20. The detection signal can be amplified and output. Therefore, even when noise due to vibration of the internal combustion engine or the like occurs, a detection signal with very little noise can be suitably amplified near the sensor 20 by the amplifier circuit 58 directly connected to the base end of the sensor 20. It becomes possible. As a result, the detection accuracy of the in-cylinder pressure by the sensor 20 can be improved.

  The first signal transmission member 54 is a first conductive layer of a circuit layer including first power supply layers 64 a and 64 b connected to the power terminal 46 and a first output transmission layer 66 connected to the signal terminal 22. It is connected to the amplifier circuit 58 through 62. Therefore, the first signal transmission member 54 can be reduced in size in the radial direction as compared with the case where it is connected to the amplifier circuit 58 with a lead wire or the like, and accordingly, the first signal transmission member 54 is included. It becomes possible to make the fuel injection valve 10 into a compact structure.

  Further, like the first signal transmission member 54, the second signal transmission member 56 includes the first power supply layers 72 a and 72 b and the second output transmission layer 74 through the second conductive layer 70. Since the signal transmission member 54 is connected to the power terminal 46 and the signal terminal 22, the second signal transmission member 56 can be reduced in size in the radial direction. It becomes possible to reduce the diameter of the housing 12 to be accommodated.

  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 ... Resin mold part 20 ... Sensor 22 ... Signal terminal 24 ... Signal transmission part 42 ... Coupler part 46 ... Power supply terminal 54 ... 1st signal transmission member 56 ... 2nd signal transmission Member 58 ... Amplifier circuit 60 ... Insulator 62 ... First conductive layer 64a, 64b ... First power supply layer 66 ... First output transmission layer 72 ... Second conductive layer 72a, 72b ... Second power supply layer 74 ... Second Output transmission layer

Claims (2)

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 signal transmission member that transmits the in-cylinder pressure detected by the sensor as a detection signal;
The signal transmission member includes a first transmission unit connected to the sensor;
A second transmission unit connected to the first transmission unit and outputting the detection signal to the outside;
An amplification circuit provided in the first transmission unit and directly connected to the sensor for amplifying the detection signal;
With
The fuel injection valve with an in-cylinder pressure sensor, wherein power supply means for supplying power to the amplifier circuit is a circuit layer provided in the signal transmission member. The fuel injection valve with an in-cylinder pressure sensor according to claim 1,
The fuel injection valve with an in-cylinder pressure sensor, wherein the signal output means for outputting the detection signal amplified by the amplifier circuit is a circuit layer provided in the signal transmission member.

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