CN210129651U

CN210129651U - Spark plug

Info

Publication number: CN210129651U
Application number: CN201921497998.5U
Authority: CN
Inventors: 周桐; 邢强; 王伟
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2019-09-10
Filing date: 2019-09-10
Publication date: 2020-03-06
Anticipated expiration: 2029-09-10

Abstract

The present application provides a spark plug, wherein the insulator includes preceding main part and head that connect in the axial, and runs through preceding main part and head in the axial and sets up the mesopore, sets up the water storage portion in the outer peripheral face of head. The first electrode is fixed in the middle hole and has a discharge portion protruding out of the head portion. The second electrode is fixed outside the middle hole, a discharge gap is formed between the second electrode and the discharge part, and the second electrode and the water storage part are spaced. The spark plug greatly improves the smooth starting performance of the internal combustion engine under extreme cold conditions.

Description

Spark plug

Technical Field

The present application relates to internal combustion engine ignition devices, and more particularly to spark plugs.

Background

The spark plug includes a center electrode and a side electrode with a discharge gap therebetween. The spark plug forms a spark to ignite by discharging a high voltage breakdown discharge gap. However, in cold conditions, the spark plug may freeze and fail to ignite, resulting in a failure of the engine to start successfully. In cold regions such as russia, a preheating device is usually installed to melt frozen ice before ignition, so that the internal combustion engine can be started smoothly even in extreme cold. However, there are still many vehicles that do not have a pre-heater unit, as this adds significant cost.

SUMMERY OF THE UTILITY MODEL

The present application mainly solves at least one technical problem existing in the prior art.

In order to solve the above technical problem, the present application provides a spark plug including:

an insulator including a front body and a head connected to each other in an axial direction, a central hole provided through the front body and the head in the axial direction, and a water storage portion provided on an outer peripheral surface of the head;

a first electrode fixed in the central hole and having a discharge portion protruding out of the head portion; and

and the second electrode is fixed outside the middle hole, a discharge gap is formed between the second electrode and the discharge part, and the second electrode and the water storage part are spaced.

According to the technical scheme of this application, set up the water storage portion in the outer peripheral face of head, when the spark plug after the cooling at the head moisture condensation, moisture can be stored in the water storage portion and not flow between first electrode and the second electrode, reduces the risk that the discharge gap freezes. The smooth starting performance of the internal combustion engine under extreme cold conditions is greatly improved.

Drawings

Specific embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 shows a schematic view of an embodiment of a spark plug;

FIG. 2 shows a schematic view of the insulating ceramic of the spark plug of FIG. 1; and

FIG. 3 is an enlarged partial view of the insulating ceramic of the spark plug of FIG. 1.

Detailed Description

Referring to fig. 1 to 3, a spark plug 100 according to an embodiment of the present invention includes an insulator 1, a first electrode 2, a second electrode 3, and a conductive shell 4.

The insulator 1 includes a rear body portion 11, a flange portion 12, a front body portion 14, and a head portion 18 connected in the axial direction. A central hole 10 is provided through the insulator 1. The center hole 10 axially penetrates the front body portion 14 and the head portion 18. The water reservoir 13 is provided on the outer peripheral surface of the head 18. The flange portion 12 is positioned between the front body portion 14 and the rear body portion 11, and a shoulder portion 16 is provided between the head portion 18 and the front body portion 14.

A central cavity 40 is axially provided through the housing 4, and both ends of the housing 4 are fixed to the flange portion 12 and the shoulder portion 16 while being inwardly narrowed, respectively. The front body portion 14 is fixed in the central cavity 40 and the rear body portion 11 extends from the upper end of the housing 4, outside the housing 4.

The first electrode 2 is fixed in the central hole 10 and has a discharge portion 20 protruding outside the head portion 18. The second electrode 3 is integrally provided at one axial end of the housing 4. For example, the second electrode 3 is formed integrally with the outer case 4, or the second electrode 3 is welded integrally with the outer case 4. The second electrode 3 is fixed outside the middle hole 10, a discharge gap is formed between the second electrode 3 and the discharge part 20, and the second electrode 3 is spaced from the water storage part 13.

The front body portion 14 and the head portion 18 are integrally made of a ceramic material. The head 18 projects axially beyond the housing 4, sealing between the shoulder 16 and the housing 4. Axially, head 18 includes opposite distal and proximal ends. Proximal to the front body portion 14 and distal to the front body portion 14, the distal end having a diameter smaller than the proximal end. The ratio d1/d2 of the maximum diameter d1 of the water storage part 13 to the inner diameter d2 of the middle hole 10 is not more than 4.02 and not less than 2.02, i.e., 2.02< = d1/d2< = 4.02. The water reservoir 13 is also made of a ceramic material or other insulating and heat-resistant material. The reservoir 13 is adhered or otherwise secured to the outside of the head 18. Or the reservoir 13 may be formed integrally with the head 18. That is, the water storage part 13 may be designed to be integrally formed with the head part 18 or assembled with the head part 18 as required. The reservoir 13 comprises a ring surrounding the head 18, the ring having a relief height h of not less than 0.3 mm. In some embodiments, the reservoir 13 includes at least two rings surrounding the head 18, each ring having a relief height h of no less than 0.3 mm. As shown in fig. 3, the reservoir 13 includes three rings around the head 18. The smallest ring has a relief height of not less than 0.3 mm, and the diameter of the ring near the distal end is smaller than the diameter of the ring near the proximal end. The ratio d1/d3 of the maximum diameter d1 of the water storage part 13 to the diameter d3 of the root zone of the front main body part 14 is not more than 0.93 and not less than 0.47, i.e., 0.93> = d1/d3> = 0.47. Not only the water storage part 13 has a good water storage effect, but also the insulator 1 has good manufacturing ease and structural strength.

A gap is arranged between the head part 18 and the inner wall surface of the middle cavity 40, the curvature radius r of the protruding part of the water storage part 13 is not less than 0.2 mm, and the water storage part 13 does not contact the shell 4. Leakage discharge between the water storage part 13 and the housing 4 is not easily caused.

Since the water reservoir 13 is provided on the outer peripheral surface of the head portion 18, when water is condensed at the head portion of the spark plug 100, the water can be stored in the water reservoir 13 without flowing between the first electrode 2 and the second electrode 3, and the risk of freezing of the discharge gap is reduced. The spark plug 100 greatly improves the ability of the engine to start successfully in extreme cold conditions.

Notwithstanding the foregoing, the scope of protection of the present application is defined by the claims.

Claims

1. Spark plug (100), characterized in that it comprises:

an insulator (1) which includes a front body (14) and a head (18) connected in an axial direction, wherein a center hole (10) is provided so as to penetrate the front body (14) and the head (18) in the axial direction, and a water storage section (13) is provided on an outer peripheral surface of the head (18);

a first electrode (2) fixed in the central hole (10) and having a discharge portion (20) protruding outside the head portion (18); and

and the second electrode (3) is fixed outside the middle hole (10), a discharge gap is formed between the second electrode and the discharge part (20), and the second electrode (3) is separated from the water storage part (13).

2. The spark plug (100) of claim 1, further comprising an electrically conductive outer shell (4), a central cavity (40) being provided through the outer shell (4) in the axial direction, the front body portion (14) being fixed in the central cavity (40), the second electrode (3) being integrally provided at one axial end of the outer shell (4).

3. The spark plug (100) of claim 1, wherein the front body portion (14) and the head portion (18) are integrally made of a ceramic material, the water reservoir portion (13) is integrally formed with the head portion (18) or assembled to the head portion (18), and a ratio (d 1/d 2) of a maximum diameter (d 1) of the water reservoir portion (13) to an inner diameter (d 2) of the center hole (10) is not more than 4.02 and not less than 2.02.

4. The spark plug (100) of claim 3, wherein the water reservoir (13) is also made of a ceramic material, the water reservoir (13) comprising at least one ring surrounding the head (18), the ring having a relief height (h) of not less than 0.3 mm.

5. The spark plug (100) of claim 2, wherein the insulator (1) further includes a rear main body portion (11) and a flange portion (12), the flange portion (12) being located between the front main body portion (14) and the rear main body portion (11), a shoulder portion (16) being provided between the head portion (18) and the front main body portion (14), the shell (4) being fixed to the flange portion (12) and the shoulder portion (16), the rear main body portion (11) being located outside the shell (4).

6. The spark plug (100) according to claim 2, wherein a gap is provided between the head (18) and an inner wall surface of the middle cavity (40), a radius of curvature of a protruding portion of the water reservoir portion (13) is not less than 0.2 mm, and the water reservoir portion (13) does not contact the shell (4).

7. The spark plug (100) of claim 5, wherein the head (18) includes opposite distal and proximal ends in the axial direction, the distal end having a diameter smaller than a diameter of the proximal end.

8. The spark plug (100) of claim 7 wherein said water reservoir (13) includes at least two rings surrounding said head (18), said rings having a relief height of no less than 0.3 mm, the diameter of the ring near said distal end being less than the diameter of the ring near said proximal end.

9. The spark plug (100) of claim 5, wherein the head (18) projects beyond the housing (4) in the axial direction, the shoulder (16) sealing against the housing (4).

10. The spark plug (100) of claim 8, wherein a ratio (d 1/d 3) of a maximum diameter (d 1) of the water reservoir portion (13) to a diameter (d 3) of a root region of the front main body portion (14) is not more than 0.93 and not less than 0.47.