JP6285053B2 - In-cylinder pressure detector - Google Patents

Description

  The present invention relates to an in-cylinder pressure detecting device that detects an in-cylinder pressure that is a pressure in a combustion chamber of an internal combustion engine, and in particular, an in-cylinder pressure detection that includes a pressure detecting element mounted at a tip of a fuel injection device that injects fuel into the combustion chamber. Relates to the device.

  Patent Document 1 includes a pressure detection element attached to an ignition plug or a fuel injection valve of an internal combustion engine, and an amplification circuit (charge amplifier) that amplifies a voltage change of the pressure detection element and outputs a pressure detection signal. A combustion pressure sensor is shown. In this combustion pressure sensor, the pressure detection element is fixed to the outside of the combustion chamber integrally with the fuel injection valve by, for example, a nut to which the fuel injection valve is attached, and the amplification circuit is integrated with the sensor fixing portion to which the pressure detection element is fixed. Provided.

  Patent Document 2 discloses an in-cylinder pressure detecting device in which a pressure detecting element is attached to the tip of a fuel injection valve that injects fuel into a combustion chamber, and the in-cylinder pressure is detected using the pressure detecting element.

Japanese Patent No. 4407004 International Publication WO2012 / 115036

  The combustion pressure sensor disclosed in Patent Document 1 requires room for improvement in terms of workability at the time of mounting because the sensor fixing portion needs to be sandwiched and fixed at the same time when the fuel injection valve is fixed. .

  Further, as shown in Patent Document 2, when the pressure detection element is disposed at the tip of the portion of the fuel injection valve that is inserted into the combustion chamber, the pressure detection element and the amplification circuit are disposed close to each other. It has been desired to realize the above with good workability.

  The present invention has been made paying attention to the above-mentioned points. A pressure detection element is attached to the tip of the fuel injection device (fuel injection valve) to detect the in-cylinder pressure, and to influence the drive signal of the fuel injection device. An object of the present invention is to provide an in-cylinder pressure detecting device that can reduce and improve workability when mounted on an internal combustion engine.

  In order to achieve the above object, the present invention provides a pressure detection element (2) attached to the tip of a fuel injection device (1) for injecting fuel into a combustion chamber of an internal combustion engine, and a signal output from the pressure detection element. And an amplifier circuit unit (81) including an amplifier circuit for amplifying the pressure and outputting a pressure detection signal, and providing an in-cylinder pressure detecting device for detecting the pressure in the combustion chamber. In this in-cylinder pressure detecting device, an in-cylinder pressure detecting unit (201) including the pressure detecting element (2), the amplifying circuit unit (81), and a connecting member (12) for connecting the pressure detecting element and the amplifying circuit unit. ) Is integrated with the fuel injection device to form a fuel injection device (200) with an in-cylinder pressure detection unit, and the pressure is detected by mounting the fuel injection device with an in-cylinder pressure detection unit on the internal combustion engine. The The fuel injection device (1) has a main body connector portion having detection signal line connection terminals (71 to 73) to which a detection signal line for supplying the pressure detection signal to a control unit that controls the fuel injection device is connected. (70), the in-cylinder pressure detection unit (201) is configured integrally with the amplification circuit unit (81), and can be coupled by fitting into the main body connector portion (70). Is provided. The sub connector portion has sub connection terminals (91 to 93) for transmitting the pressure detection signal to the main body connector portion, and couples the sub connector portion (82) to the main body connector portion (70). Accordingly, the sub connection terminals (91 to 93) are configured to come into contact with the detection signal line connection terminals (71 to 73).

  According to this configuration, the in-cylinder pressure detection unit with the in-cylinder pressure detection unit is configured by integrating the in-cylinder pressure detection unit including the pressure detection element, the amplification circuit unit, and the connecting member that connects them with the fuel injection device. The fuel injection device with the in-cylinder pressure detection unit is mounted on the internal combustion engine. Therefore, the influence of the drive signal of the fuel injection device can be reduced, and the workability when the pressure detection element and the amplification circuit unit are integrated with the fuel injection device and mounted on the internal combustion engine can be improved. Further, by inserting the sub connector part into the main body connector part, the amplification circuit unit of the in-cylinder pressure detection unit is fixed to the fuel injection device, and the sub connection terminal and the detection signal line connection terminal are in contact with each other. And the detection signal line connection terminal can be easily performed.

  Preferably, the main body connector part (70) is exposed to the detection signal line connection terminals (71 to 73), and accommodates the sub connection terminals (91 to 93) of the sub connector part (82). 74), the sub connection terminals (91 to 93) are connected to the detection signal line connection terminals (71 to 73) in the terminal accommodating recess, and the terminal accommodating recess is filled with an adhesive.

  According to this configuration, the sub connection terminal of the sub connector portion is connected to the detection signal line connection terminal of the main body connector portion in the terminal accommodating recess of the main body connector portion, and the terminal accommodating recess is filled with the adhesive. It is possible to reliably prevent water from entering the connection portion between the connection terminal and the detection signal line connection terminal.

Preferably, an auxiliary member (76) for preventing leakage of the adhesive is interposed in a joint portion between the sub-connector portion (82) and the main body connector portion (70).
Since there may be a gap in the joint between the sub-connector part and the main body connector part, it is possible to prevent the adhesive before solidifying from leaking through the gap by providing an auxiliary member.

  Preferably, the connecting member (12) for connecting the pressure detection element and the amplification circuit unit, the amplification circuit unit (81), and the terminal accommodating recess (74) are arranged so that the in-cylinder pressure detection unit (201) After being integrated with the fuel injection device (1), it is covered with a molding material (202).

  According to this configuration, the main part of the in-cylinder pressure detection unit is covered with the molding material, so that it is easy to handle in an integrated state with the fuel injection device, and the effects of waterproofing, heat insulation, and insulation of the amplifier circuit unit are achieved. Can be definitely obtained.

  Preferably, the amplification circuit unit (81) is sealed with a heat resistant resin (81a).

  When the coating with the molding material is finally performed, the amplification circuit unit is exposed to a relatively high temperature for a certain period of time. Therefore, the heat resistance can be increased by sealing with a heat resistant resin.

  Preferably, the in-cylinder pressure detection unit (201) includes a cylindrical sensor fixing member (13) in which the pressure detection element (2) is fixed to a tip portion, the amplification circuit unit (81), and the pressure detection. The sensor fixing member (13) is fitted into the front end portion of the fuel injection device. The sensor fixing member (13) is assembled by previously assembling a connection member (12) for connecting the element and the amplifier circuit unit.

  According to this configuration, the in-cylinder pressure detection unit is configured by assembling in advance the sensor fixing member, the amplification circuit unit, and the connection member that connects them, and the in-cylinder pressure detection unit is a cylindrical shape to which the pressure detection element is fixed. By fitting the sensor fixing member to the tip of the fuel injection device, the fuel injection device with the in-cylinder pressure detection unit is configured, so that the workability when integrating the in-cylinder pressure detection unit with the fuel injection device can be improved. it can.

  Preferably, the main body connector portion has a drive signal line connection terminal to which a drive signal line for supplying a drive signal of the fuel injection device from the control unit is connected.

  According to this configuration, since the main body connector portion includes the drive signal line connection terminals together with the detection signal connection terminals, it is possible to improve workability when connecting the connection lines from the control unit to the fuel injection device.

It is a figure for demonstrating the structure of the fuel-injection apparatus with a cylinder pressure detection unit concerning one Embodiment of this invention. It is a perspective view for demonstrating the structure and assembly procedure of a fuel-injection apparatus with a cylinder pressure detection unit shown in FIG. It is a perspective view for demonstrating in detail the coupling | bonding of a sub connector part (82) and a main-body connector part (70). It is a figure for demonstrating the structure of the synthetic resin mold (81a) which coat | covers the amplifier circuit unit (81) and forms a subconnector part (82). It is a figure for demonstrating the mounting state of a connection member (12), and a figure for demonstrating the connection of a connector pin (91-93, 71-73). It is a figure for demonstrating the structure of the connection member (12) shown in FIG. It is sectional drawing which shows the structure of the front-end | tip part vicinity of the fuel-injection apparatus with a cylinder pressure detection unit. It is a block diagram which shows the structure of the amplifier circuit unit shown in FIG. It is a figure for demonstrating the circuit for failure detection. It is a figure for demonstrating the connection of the drive solenoid of a fuel-injection apparatus, and an electronic control unit.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1A is a side view of a fuel injection device with an in-cylinder pressure detection unit of the present embodiment, and FIG. 1B is a state where the fuel injection device shown in FIG. 1A is covered with a synthetic resin mold. FIG. 1C is a diagram for explaining the main body connector 70 viewed from the direction of arrow B in FIG. FIG. 1A shows a state where there is no synthetic resin mold for the sake of explanation (however, the amplification circuit unit 81 is sealed and formed with a synthetic resin mold 81a). 2 (a) to 2 (d) show a state in which the fuel injection device 1 and the in-cylinder pressure detection unit 201 are being attached, a state in which the in-cylinder pressure detection unit 201 is attached, and an in-cylinder pressure detection unit 201, respectively. 3 shows the final form covered with the synthetic resin mold 202, that is, the fuel injection device 200 with an in-cylinder pressure detection unit. As shown in FIG. 2B, the in-cylinder pressure detection unit 201 is attached to the fuel injection device 1 by moving in the direction indicated by the arrow C.

  The fuel injection device 1 is a device that injects fuel into a combustion chamber of an internal combustion engine. Inside the valve body, which is a well-known component, a solenoid (drive circuit) that drives the valve body, a spring that biases the valve body, and the like The fuel is injected from the injection port 5 at the tip. The fuel injection device 1 includes a metal large-diameter portion casing 3 in which a solenoid is incorporated, and a metal small-diameter portion casing 4 provided with an injection port 5 at the tip.

  The in-cylinder pressure detection unit 201 connects the pressure detection element 2, the cylindrical sensor fixing member 13 with the pressure detection element 2 fixed to the tip, the amplification circuit unit 81, and the pressure detection element 2 and the amplification circuit unit 81. The in-cylinder pressure detection unit 201 is made to be fuel by inserting the sensor fixing member 13 into the distal end side (injection port 5 side) of the small diameter casing 4 of the fuel injection device 1. Mounted on the injection device 1. Therefore, the pressure detection element 2 is attached to the tip of the fuel injection device 1 (a position surrounding the injection port 5), and is connected to the amplifier circuit unit 81 by the connection member 12. The amplifier circuit unit 81 is coated (sealed) with a heat-resistant synthetic resin mold 81a. The sub-connector pins 91 to 93 are fixed to the amplification circuit unit 81, and the sub-connector portion 82 including the sub-connector pins 91 to 93 is formed by the synthetic resin mold 81a.

  The fuel injection device 1 is fixed with a main body connector portion 70 which is constituted by a part of the synthetic resin mold 203 and to which a connection line from an electronic control unit (hereinafter referred to as “ECU”) 60 (see FIGS. 8 to 9) is connected. Has been. The ECU 60 controls the drive of the fuel injection device 1 and detects the in-cylinder pressure by the in-cylinder pressure detection unit 201.

The main body connector unit 70 includes first connector pins 21 to 23 to which a drive signal line to which a drive signal of the fuel injection device 1 is supplied from the ECU 60, a detection signal line for supplying a pressure detection signal to the ECU 60, and the like ( Second connector pins 71 to 73 to which a power connection line (ground connection line) is connected, a terminal accommodating recess 74 for connecting the second connector pins 71 to 73 to the sub connector pins 91 to 93, and an in-cylinder pressure detection unit And a holding member 75 for holding the sub-connector portion 82 when the 201 is mounted. The second connector pins 71 to 73 are exposed in the terminal accommodating recess 74, and the second connector pins 71 to 73 are configured to be connectable to the sub connector pins 91 to 93.
An auxiliary member 76 for preventing leakage of the adhesive before being solidified is interposed in a joint portion between the sub connector portion 82 and the main body connector portion 70.

  A connector member (not shown) that can be fitted to the first connector pins 21 to 23 and the second connector pins 71 to 73 of the main body connector portion 70 is fixed to the distal end portion of the connection line from the ECU 60, and the connector member is By connecting, the connection lines and the connector pins 21 to 23 and 71 to 73 are connected.

  As shown in FIGS. 2C and 2D, after the in-cylinder pressure detection unit 201 and the fuel injection device 1 are integrated, the amplifier circuit unit 81 covered with the synthetic resin mold 81a, the connection member 12, and A part of the sensor fixing member 13 (side closer to the amplification circuit unit 81) is covered with the synthetic resin mold 202. Note that after the in-cylinder pressure detection unit 201 and the fuel injection device 1 are integrated and before the covering with the synthetic resin mold 202 is performed, the sub connector pins 91 to 93 are connected to the second connector pins 71 to 73, respectively. Resistance welding is performed, and the terminal accommodating recess 74 is filled with a waterproofing adhesive (for example, a silicon adhesive).

  In FIG. 1 (b), the portion indicated by the right-down hatching corresponds to the synthetic resin mold 203 constituting the main body connector portion 70 of the fuel injection device 1 shown in FIG. 2 (a). The portion indicated by is equivalent to the last synthetic resin mold 202 shown in FIG.

  FIG. 3 is a perspective view for explaining the connection between the sub connector pins 91 to 93 and the second connector pins 71 to 73 in more detail, and FIG. 3A shows the sub connector portion 82 and the main body connector portion. FIG. 7B shows a state where the connection is completed, and FIG. 5C shows a state where the adhesive 77 is filled after the resistance welding of the connector pin is completed.

  An auxiliary member 76 is interposed between the sub-connector portion 82 and the main body connector portion 70, and the sub-connector portion 82 is sandwiched between the two holding members 75 of the main body connector portion 70 by being pushed rightward in the drawing. It is fixed ((b) in the figure). In the state where the connection shown in FIG. 3B is completed, the terminal accommodating recess 74, the sub connector portion 82, and the auxiliary member 76 form a storage portion capable of storing the adhesive before solidification, and the auxiliary member 76 is By interposing, leakage of the adhesive before solidifying from the coupling portion is prevented.

  FIG. 4 is a diagram for explaining in detail the structure of a synthetic resin mold 81a that covers the amplifier circuit unit 81 and forms the sub-connector portion 82. FIGS. 4A to 4D are respectively synthetic resin molds. 81a (including sub-connector pins 91 to 93) is a perspective view, a plan view, a front view, and a side view, and a plan view of the auxiliary member 76 is also shown in the plan view (b).

  The synthetic resin mold 81a forms a sub-connector portion 82 that holds the sub-connector pins 91 to 93, a bottom surface 83 that is curved so as to be in close contact with the outer peripheral surface of the large-diameter portion casing 3 of the fuel injection device 1, and a fixing protrusion. 84. The fixing projection 84 is fitted into a fixing recess (not shown) provided in the large diameter casing 3, and the synthetic resin mold 81 a is fixed on the large diameter casing 3. The sub-connector portion 82 is formed with a taper portion 85, and when the sub-connector portion 82 is coupled to the main body connector portion 70, the sub-connector portion 82 is smoothly interposed between the two holding members 75. It becomes possible to fit in.

  The auxiliary member 76 has notches 76 a, 76 b, and 76 c corresponding to the sub connector pins 91 to 93, and when the sub connector 82 is coupled to the main body connector 70, the sub connector pins 91 to 93 are cut. It is configured to pass through the notches 76a, 76b, and 76c.

  FIG. 5A is a diagram for explaining a mounting state of the connection member 12, and the connection member 12 connected to the amplifier circuit unit 81 is mounted so as to be in contact with the large-diameter casing 3 as much as possible. . This prevents the connection member 12 from being peeled off (raised) when finally covering the synthetic resin mold 202.

  FIG. 5B is a diagram for explaining the connection between the sub-connector pins 91 to 93 and the second connector pins 71 to 73. When the sub-connector portion 82 is coupled to the main body connector portion 70, the sub-connector The pins 91 (92, 93) are in contact with the second connector pins 71 (72, 73) in the terminal accommodating recess 74. And both are connected by carrying out resistance welding of this contact part (it shows with the ellipse PW of a broken line). The auxiliary member 76 is interposed between the sub-connector portion 82 and the main body connector portion 70, and is fixed at the position shown in this figure.

  6A and 6B are diagrams for explaining the structure of the connecting member 12, in which FIG. 6A is a plan view and FIG. 6B is a cross-sectional view taken along line AA of FIG. 6A. The connecting member 12 has a structure known as a flexible wiring board configured by covering the copper wire 17 with the polyimide covering members 14 and 15 via the adhesive 16 (epoxy resin), and is disconnected. And can be bent easily. The connection member 12 is connected to the pressure detection element 2 in the vicinity of the distal end (the portion indicated by RIN in FIG. 6A) passes through the inside of the metal sensor fixing member 13 as shown in FIG. Between the vicinity portion RIN and the amplification circuit unit 81, the fuel injection device 1 is disposed along the outer peripheral surface of the large-diameter casing 3.

  FIG. 8 is a block diagram showing the configuration of the amplifier circuit unit 81. The amplifier circuit unit 81 includes a capacitor 41, a low-pass filter 42, a charge amplifier 43, a high-pass filter 44, an amplifier circuit 45, a sensitivity adjustment circuit 46, and a failure detection circuit. 47, a reference voltage circuit 48, a power supply noise filter 49, an AC grounding capacitor 50, and sub connector pins 91 to 93 constituting the sub connector portion 82. The sub connector pin 91 is connected to the ground of the ECU 60 via the main body connector portion 70 (connector pin 71) and the ground connection wire 61, and the main connector portion 70 (connector pin 72) and the power supply connection wire 62 are connected to the sub connector pin 92. A DC power supply voltage (for example, 5 V) is supplied via the connector, and the sub connector pin 93 is connected to the AD converter of the ECU 60 via the main body connector portion 70 (connector pin 73) and the signal connection line (detection signal line) 63. Is done. The power supply line 53 connected to the sub connector pin 92 is connected to the reference voltage circuit 48 via the power supply noise filter 49.

  The capacitor 41 cuts the DC component of the input detection signal from the pressure detection element 2 through the connection member 12, and only the AC component of the input detection signal is input to the low-pass filter 42. The low pass filter 42 attenuates unnecessary high frequency components. The charge amplifier 43 converts the input signal indicating the pressure change rate into a pressure signal indicating the pressure value by amplifying the input signal while integrating the input signal. The high pass filter 44 attenuates unnecessary low frequency components. The amplifier circuit 45 amplifies the output signal of the high pass filter 44.

  The sensitivity adjustment circuit 46 is composed of, for example, a combination of a plurality of resistance elements, and the output signal level of the amplification circuit 45 when the pressure detection element 2 is connected and a test pressure is applied to the pressure detection element 2 is predetermined. This is a circuit for adjusting the gain of the amplifier circuit 45 so as to be at the level. Specifically, the resistance value as a whole is adjusted by cutting a wiring connecting a plurality of resistance elements mounted in advance, and gain adjustment is performed. This gain adjustment is performed before the amplification circuit unit 81 is covered with the synthetic resin mold 81a.

  The reference voltage circuit 48 generates a reference voltage VREF from the power supply voltage VS1 supplied from the ECU 60 and supplies the reference voltage VREF to the charge amplifier 43, the high-pass filter 44, and the amplifier circuit 45. The reference voltage VREF is a voltage for offsetting the DC voltage (raising 0V to 1V). The power supply noise filter 49 is a low-pass filter that removes noise mixed through the power supply connection line 62.

  The ground wire 52 of the amplifier circuit unit 81 is connected to the ground of the ECU 60 through the sub connector portion 82, the main body connection portion 70, and the ground connection wire 61, but the housing of the fuel injection device 1 is an AC grounding capacitor. 50, and is not connected to the casing of the fuel injection device 1 in terms of direct current. As a result, the disconnection of the ground connection line 61 can be detected by the ECU 60 as described below. Note that the housing of the fuel injection device 1 is electrically connected to the cylinder head of the internal combustion engine.

  The failure detection circuit 47 is configured by connecting a pull-up resistor RPU to the power supply line LS as shown in FIG. The ECU 60 is provided with a pull-down resistor RPD connected to the ground. The power connection line 62 or the signal connection line 63 is disconnected or grounded (short-circuited with the ground) or the ground connection line 61 according to the input DC voltage VIN. The disconnection is configured to be detectable. That is, when the connection line 62 or 63 is disconnected or a ground fault occurs, the input DC voltage VIN becomes “0”, and when the ground connection line 61 is disconnected, the input DC voltage VIN becomes higher than the normal voltage VNL. Therefore, when the input DC voltage VIN is higher than the normal voltage VNL by a predetermined voltage or higher, it can be determined that the ground connection line 61 is disconnected.

  FIG. 10 is a diagram for explaining the connection between the drive solenoid 24 of the fuel injection device 1 and the ECU 60, and both ends of the solenoid 24 are connected to the ECU 60 via the first connector pins 22 and 23 of the main body connector portion 70. The first connector pin 21 is connected to the housing in the fuel injection device 1.

  As described above, in the present embodiment, the in-cylinder pressure detection unit 201 is integrated with the fuel injection device 1 by integrating the in-cylinder pressure detection unit 201 including the pressure detection element 2, the amplifier circuit unit 81, and the connection member 12 connecting them. A fuel injection device 200 with a cylinder is configured, and the fuel injection device 200 with an in-cylinder pressure detection unit is mounted on an internal combustion engine. Therefore, the influence of the drive signal of the fuel injection device 1 can be reduced, and the workability when the pressure detection element 2 and the amplification circuit unit 81 are integrated with the fuel injection device 1 and mounted on the internal combustion engine can be improved. Further, by fitting the sub connector portion 82 into the main body connector portion 70, the amplification circuit unit 81 of the in-cylinder pressure detection unit 201 is fixed to the fuel injection device 1, and the sub connector pins 91 to 93 and the second connector pins 71 to 71 are fixed. Since 73 contacts, the operation | work which connects the sub connector pins 91-93 and the 2nd connector pins 71-73 can be performed easily.

  Further, the in-cylinder pressure detection unit 201 is configured by assembling in advance the cylindrical sensor fixing member 13 to which the pressure detection element 2 is fixed, the amplification circuit unit 81, and the connection member 12 that connects the pressure detection element 2 and the amplification circuit unit 81. Since the in-cylinder pressure detection unit 201 fits the sensor fixing member 13 into the front end portion of the fuel injection device 1 (the front end side of the small-diameter portion casing 4), the fuel injection device 200 with in-cylinder pressure detection unit is configured. The workability when the in-cylinder pressure detection unit 201 is integrated with the fuel injection device 1 can be improved.

  Further, the sub connector pins 91 to 93 are connected to the second connector pins 71 to 73 in the terminal accommodating recess 74 of the main body connector portion 70, and the adhesive 77 is filled in the terminal accommodating recess 74. It is possible to reliably prevent water from entering the connecting portion between the second connector pins 71 and 73 and the second connector pins 71 to 73.

  Further, since an auxiliary member 76 for preventing the leakage of the adhesive 77 is interposed at the joint between the sub connector 82 and the main body connector 70, the adhesive before solidifying leaks from the gap between the joints. Can be prevented.

  The main part of the in-cylinder pressure detection unit 201, that is, the amplification circuit unit 81 covered with the synthetic resin mold 81 a, the connection member 12, and a part of the sensor fixing member 13 (part close to the amplification circuit unit 81) are the synthetic resin mold 202. Therefore, handling in an integrated state with the fuel injection device 1 is facilitated, and waterproofing, heat insulation, and insulation effects of the amplifier circuit unit 81 can be reliably obtained.

  In addition, since the amplification circuit unit 81 is covered (sealed and molded) with the heat-resistant synthetic resin mold 81a, the heat-resistance is increased and finally the synthetic resin mold 202 is fixed at a relatively high temperature. Even if it is exposed to time, it can be avoided reliably.

  Moreover, since the main body connector part 70 is provided with the 1st connector pins 21-23 to which a drive signal line is connected with the 2nd connector pins 71-73, the workability | operativity at the time of connecting the connection line from ECU60 to the fuel-injection apparatus 1 Can be increased.

[Modification]
In the embodiment described above, the main body connector portion 70 includes the first connector pins 21 to 23 and the second connector pins 71 to 73. However, the main body connector portion 70 includes the first main body connector portion and the second main body connector portion. The main body connector portion is divided into main body connector portions, and the first main body connector portion has connector pins 21 to 23 of the fuel injection device 1, and the second main body connector portion is connected to the sub connector pins 91 to 93 of the amplifier circuit unit 81. It is good also as a structure which has the connector pins 71-73.

  Thus, by dividing the main body connector portion 70 into the first and second main body connector portions, the connection line 63 for transmitting the pressure detection signal is separated from the drive signal line through which a relatively large current flows, and the fuel injection device The influence of the driving signal 1 on the pressure detection signal can be reduced.

The synthetic resin molds 202 and 203 may be replaced with ceramic molds. Further, the sensitivity adjustment circuit 46 of the amplifier circuit unit 81 is configured by a combination of a plurality of resistance elements. However, the present invention is not limited to this. For example, gain adjustment may be performed by writing gain adjustment data in a nonvolatile memory. Good.
The amplifier circuit unit 81 may be configured on a glass epoxy resin substrate, and the connection member 12 may be connected to the glass epoxy resin substrate.

DESCRIPTION OF SYMBOLS 1 Fuel injection apparatus 2 Pressure detection element 21-23 1st connector pin 60 Electronic control unit 70 Main body connector part 71-73 2nd connector pin 74 Terminal accommodation recessed part 76 Auxiliary member 77 Adhesive agent 81 Amplifying circuit unit 81a Synthetic resin mold 82 Sub Connector portion 91-93 Sub connector pin 200 Fuel injection device with in-cylinder pressure detection unit 201 In-cylinder pressure detection unit 202 Synthetic resin mold

Claims (7)

An amplifying circuit including a pressure detecting element mounted at a tip of a fuel injection device for injecting fuel into a combustion chamber of an internal combustion engine, and an amplifying circuit for amplifying a signal output from the pressure detecting element and outputting a pressure detecting signal An in-cylinder pressure detecting device for detecting a pressure in the combustion chamber,
A fuel with an in-cylinder pressure detecting unit is integrated with the fuel injection device by integrating the in-cylinder pressure detecting unit including the pressure detecting element, the amplifying circuit unit, and a connecting member for connecting the pressure detecting element and the amplifying circuit unit. Constituting an injection device, mounting the fuel injection device with in-cylinder pressure detection unit on the internal combustion engine to detect the pressure;
The fuel injection device includes a main body connector portion having a detection signal line connection terminal to which a detection signal line for supplying the pressure detection signal to a control unit that controls the fuel injection device is connected.
The in-cylinder pressure detection unit is configured integrally with the amplification circuit unit, and includes a sub-connector portion that can be coupled by being fitted into the main body connector portion.
The sub connector portion has a sub connection terminal for transmitting the pressure detection signal to the main body connector portion, and the sub connection terminal is connected to the main body connector portion so that the sub connection terminal is connected to the detection signal. An in-cylinder pressure detecting device configured to be in contact with a line connecting terminal.   The main body connector portion has a terminal receiving recess that exposes the detection signal line connection terminal and receives the sub connection terminal of the sub connector portion, and the sub connection terminal is connected to the detection signal line in the terminal receiving recess. The in-cylinder pressure detecting device according to claim 1, wherein the in-cylinder pressure detecting device is connected to a terminal and is filled with an adhesive in the terminal receiving recess.   The in-cylinder pressure detecting device according to claim 2, wherein an auxiliary member for preventing leakage of the adhesive is interposed in a joint portion between the sub connector portion and the main body connector portion.   The connecting member that connects the pressure detection element and the amplification circuit unit, the amplification circuit unit, and the terminal accommodating recess are covered with a molding material after the in-cylinder pressure detection unit is integrated with the fuel injection device. The in-cylinder pressure detection device according to claim 2 or 3.   The in-cylinder pressure detection device according to claim 4, wherein the amplification circuit unit is sealed with a heat-resistant resin.   The in-cylinder pressure detection unit includes in advance a cylindrical sensor fixing member in which the pressure detection element is fixed to a distal end portion, the amplification circuit unit, and a connection member that connects the pressure detection element and the amplification circuit unit. The in-cylinder pressure detecting device according to any one of claims 1 to 5, wherein the in-cylinder pressure detecting device is configured by assembling, and the sensor fixing member is fitted into a tip portion of the fuel injection device.   The in-cylinder pressure detection according to any one of claims 1 to 6, wherein the main body connector portion has a drive signal line connection terminal to which a drive signal line for supplying a drive signal of the fuel injection device from the control unit is connected. apparatus.

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