Pressure sensor unit having a ring-like pressure sensing element

• US 7,107,819 B2
• Filed: 11/27/2001
• Issued: 09/19/2006
• Est. Priority Date: 11/30/2000
• Status: Expired due to Fees

• Current Assignee: NGK Spark PLUG Company Limited (Niterra Co., Ltd.)
• Original Assignee: NGK Spark PLUG Company Limited (Niterra Co., Ltd.)
• Inventors: Oozawa, Keiichi, Suzuki, Takahiro, Okazaki, Koji, Matsui, Masayoshi
• Primary Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US10/433,059
• Publication Number:
  US 20040055388A1
• Time in Patent Office: 1,757 Days
• Field of Search: 73/350.1, 73/350.7, 73/351.2, 731/12, 731/15, 731/16, 731/172, 731/173, 731/181
• US Class Current: 73/35.12
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02P 13/00 Sparking plugs structurally combined with other parts of internal-combustion engines connection of ignition coil to spark plug connector F02P3/02; with fuel injectors F02M57/06 ; spark plug connector per se H01T13/04 – H01T13/06; predominant aspects of sparking plug, see H01T13/40 – H01T13/44
• CPC Class Codes: G01L 23/10 by pressure-sensitive members of the piezoelectric type
• CPC Class Codes: G01L 23/22 for detecting or indicating knocks in internal-combustion engines; Units comprising pressure-sensitive members combined with ignitors for firing internal-combustion engines
• CPC Class Codes: H01T 13/44 with transformers, e.g. for high-frequency ignition

Abstract

According to the present invention, there is provided a pressure sensor unit (1) having a ring-like pressure sensing element (3), which is formed separately from a spark plug, in the state where a spark plug (100) has been attached a rear end of at least one of an inner cylinder member (6) and an outer cylinder member (5) in the direction of an axis (O) is located between the rear end of the pressure sensing element (3) and the rear end of a insulator (110) of the spark plug (standard section (SS)), while at the rear of the standard section (SS), no component of the pressure sensor unit (1) exists in an area inside the inner circumferential surface of the outer cylinder member (5) or its extended plate (EP).

Claims

1. A pressure sensor unit (1, 200, 210, 220, 230) in which a ring-like pressure sensing element (3) is incorporated in a cylindrical unit body portion (2) having a spark plug insertion hole (4) formed in a bottom surface thereof, the pressure sensing element (3) surrounding the spark plug insertion hole (4);

when a side where the pressure sensing element (3) is located in a direction of an axis (O) is set as a front end side, the unit body portion (2) is inserted into and fixed to a plug hole (PH) from the front end side in the direction of the axis (O); and

in that state, a spark plug (100) is inserted into the spark plug insertion hole (4) to be thereby attached to an attachment hole (PF) at a bottom of the plug hole (PH), so that the pressure sensing element (3) is nipped and retained between a sensor support portion (102) projecting like a collar from an outer circumferential surface of a metal shell (101) of the spark plug (100), and an opening circumferential edge portion (GS) of the attachment hole (PF);

wherein

the pressure sensing element (3) is disposed in a clearance (7) formed between an outer cylinder member (5) forming an outer circumferential surface portion of the unit body portion (2) and an inner cylinder member (6) forming an inner circumferential surface portion likewise, and an output from the pressure sensing element (3) is extracted by a sensor output lead wire (9) via a sensor output terminal (8) led out into the clearance (7); and

in a state where the spark plug (100) has been attached, a rear end of at least one of the inner cylinder member (6) and the outer cylinder member (5) in the direction of the axis (O) is located between a rear end of the pressure sensing element (3) and a rear end of an insulator (110) of the spark plug (100) (hereinafter, referred to as “

in a standard section (SS)”

), while at a rear of the standard section (SS), no component of the pressure sensor unit (1) exists in an area inside an inner circumferential surface (5b) of the outer cylinder member (5) or an extended plane (EP) thereof.

2. The pressure sensor unit (1, 200, 210, 220, 230) according to claim 1, wherein the outer cylinder member (5) comprises an outer cylinder body portion (5m) having a cylindrical outer circumferential surface, and the sensor output lead wire (9) connected to the sensor output terminal (8) is passed between an inner circumferential surface of the outer cylinder body portion (5m) and an outer circumferential surface of the inner cylinder member (6) in a section between a rear end surface of the pressure sensing element (3) and an extraction position (AP) at a predetermined distance on the rear side in the direction of the axis (O), while the sensor output lead wire (9) is extracted outside an outer circumferential surface (5c) of the outer cylinder body portion (5m) in a section behind the extraction position (AP).

3. The pressure sensor unit (1, 200, 210, 220, 230) according to claim 1, wherein a lead wire support portion (11, 5e, 6e, 30, 40) for supporting the sensor output lead wire (9) extending behind the standard section in the direction of the axis (O) is provided integrally with the unit body (2).

4. The pressure sensor unit (1, 210, 220) according to claim 3, wherein fixation portions (12) for fixing the sensor output lead wire (9) to the lead wire support portion (11, 5e, 6e) are provided at predetermined intervals in the direction of the axis (O) in the lead wire support portion (11, 5e, 6e).

5. The pressure sensor unit (230) according to claim 3, wherein the lead wire support portion is a cylindrical support (40) to which the sensor output lead wire (9) is inserted in the direction or the axis (O).

6. The pressure sensor unit (1, 200, 230) according to claim 1 wherein bath a rear edge (6a) of the inner cylinder member (6) and a rear edge (5a) of the outer cylinder member (5) are located in the standard section (SS).

7. The spark plug (1, 200) according to claim 6, wherein the lead wire support portion (11) has a sheet-like member disposed along the sensor output lead wire.

8. The pressure sensor unit (230) according to claim 6, wherein the lead wire support portion has a polymeric material molded portion (30) integrated with the sensor output lead wire (9).

9. The pressure sensor unit according to claim 1, wherein the inner cylinder member (6) has a bulge portion (6g) in which an end portion wall on a front end side in the direction of the axis (O) is bulged inward radially, and an inner circumferential surface of the bulge portion (6g) is formed as the spark plug insertion hole (4), while the outer cylinder member (5) and the bulge portion (6g) of the inner cylinder member (6) are integrated on the front end side in the direction of the axis (O), and a bottom closing portion (14) for closing the clearance (7) on the side is provided, while the bulge portion (5f), a wall portion (5h) of the outer cylinder member (5) opposite to the bulge portion (5f), and the bottom closing portion (14) form a sensor receiving portion (15) for receiving the pressure sensing element (3);

and

wherein in a state where the spark plug (100) has been attached, the pressure sensing element (3) is, together with the sensor receiving portion (15), nipped between the sensor support portion (102) and the opening circumferential edge portion (GS) of the attachment hole (PF).

10. The pressure sensor unit according to claim 1, wherein an inside of the clearance (7) is formed as a polymeric material filled-up portion (16).

11. A pressure sensor unit (1, 200, 210, 220, 230) in which a ring-like pressure sensing element (3) is incorporated in a cylindrical unit body portion (2) having a spark plug insertion hole (4) formed in a bottom surface thereof, the pressure sensing element (3) surrounding the spark plug insertion hole (4);

when a side where the pressure sensing element (3) is located in a direction of an axis (O) is set as a front end side, the unit body portion (2) is inserted into and fixed to a plug hole (PH) from the front end side in the direction of the axis (O); and

in that state, a spark plug (100) is inserted into the spark plug insertion hole (4) to be thereby attached to an attachment hole (PF) at a bottom of the plug hole (PH), so that the pressure sensing element (3) is nipped and retained between a sensor support portion (102) projecting like a collar from an outer circumferential surface of a metal shell (101) of the spark plug (100), and an opening circumferential edge portion (GS) of the attachment hole (PF);

wherein

the pressure sensing element (3) is disposed in a clearance (7) formed between an outer cylinder member (5) forming an outer circumferential surface portion of the unit body portion (2) and having an outer cylinder body portion (5m) having a cylindrical outer circumferential surface, and an inner cylinder member (6) forming an inner circumferential surface portion likewise, and an output from the pressure sensing element (3) is extracted by a sensor output lead wire (9) via a sensor output terminal (8) led out into the clearance (7); and

in a state where the spark plug (100) has been attached, a rear end of at least one of the inner cylinder member (6) and the outer cylinder member (5) in the direction of the axis (O) is located between a rear end of the pressure sensing element (3) and a rear end of an insulator (110) of the spark plug (100) (hereinafter, referred to as “

in a standard section (SS)”

), while at a rear of the standard section (SS), a radially outer edge position of the sensor output lead wire (9) with respect to the axis (O) is located outside an inner circumferential surface position of the outer cylinder body portion (5m) in the radial direction.

12. The pressure sensor unit (1, 200, 210, 220, 230) according to claim 11, wherein the outer cylinder member (5) comprises an outer cylinder body portion (5m) having a cylindrical outer circumferential surface, and the sensor output lead wire (9) connected to the sensor output terminal (8) is passed between an inner circumferential surface of the outer cylinder body portion (5m) and an outer circumferential surface of the inner cylinder member (6) in a section between a rear end surface of the pressure sensing element (3) and an extraction position (AP) at a predetermined distance on the rear side in the direction of the axis (O), while the sensor output lead wire (9) is extracted outside an outer circumferential surface (5c) of the outer cylinder body portion (5m) in a section behind the extraction position (AP).

13. The pressure sensor unit (1, 200, 210, 220, 230) according to claim 11, wherein a lead wire support portion (11, 5e, 6e, 30, 40) for supporting the sensor output lead wire (9) extending behind the standard section in the direction of the axis (O) is provided integrally with the unit body (2).

14. The pressure sensor unit (1, 210, 220) according to claim 13, wherein fixation portions (12) for fixing the sensor output lead wire (9) to the lead wire support portion (11, 5e, 6e) are provided at predetermined intervals in the direction of the axis (O) in the lead wire support portion (11, 5e, 6e).

15. The pressure sensor unit (230) according to claim 13, wherein the lead wire support portion is a cylindrical support (40) to which the sensor output lead wire (9) is inserted in the direction of the axis (O).

16. The pressure sensor unit (1, 200, 230) according to claim 11, wherein both a rear edge (6a) of the inner cylinder member (6) and a rear edge (5a) of the outer cylinder member (5) are located in the standard section (SS).

17. The spark plug (1, 200) according to claim 16, wherein the lead wire support portion (11) has a sheet-like member disposed along the sensor output lead wire.

18. The pressure sensor unit (230) according to claim 16, wherein the lead wire support portion has a polymeric material molded portion (30) integrated with the sensor output lead wire (9).

19. The pressure sensor unit according to claim 11, wherein the inner cylinder member (6) has a bulge portion (6g) in which an end portion wall on a front end side in the direction of the axis (O) is bulged inwardly radially, and an inner circumferential surface of the bulge portion (6g) is formed as the spark plug insertion hole (4), while the outer cylinder member (5) and the bulge portion (6g) of the inner cylinder member (6) are integrated on the front end side in the direction of the axis (O), and a bottom closing portion (14) for closing the clearance (7) on the side is provided, while the bulge portion (5f), a wall portion (5h) of the outer cylinder member (5) opposite to the bulge portion (5f), and the bottom closing portion (14) form a sensor receiving portion (15) for receiving the pressure sensing element (3);

and

wherein in a state where the spark plug (100) hats been attached, the pressure sensing element (3) is, together with the sensor receiving portion (15), nipped between the sensor support portion (102) and the opening circumferential edge portion (GS) of the attachment hole (PF).

20. The pressure sensor unit according to claim 11, wherein an inside of the clearance (7) is formed as a polymeric material filled-up portion (16).