EP0167687A1

EP0167687A1 - A spark plug with a ring-shaped ground electrode

Info

Publication number: EP0167687A1
Application number: EP84304704A
Authority: EP
Inventors: Wen-Tu Wang
Original assignee: WANG WEN TU
Current assignee: WANG WEN TU
Priority date: 1984-07-10
Filing date: 1984-07-10
Publication date: 1986-01-15

Abstract

Spark plug comprising a center electrode (21) and a ground electrode (22) having a discharging surface designed into a hollow round frame.

Description

This invention relates to a spark plug, particularly, a spark plug with a ring-shaped ground electrode.
In the conventional spark plug (as shown in fig. 1 and 2), tha portion of the ground electrode 9 under the center electrode 8 is a rectangular piece; between the two electrodes, there is a spark gap 10. Upon sparking, a rectangle-ahaped discharge 11 will take place. After a period of time, the discharging surface of the ground electrode will be coated with carbonized deposits, and this is particularly true to the two-stroke engine. Usually, the electrodes near the spark gap are coated with some granular carbonized deposits, which may result in engine failure or engine unable to start; all these troubles would put the user to inconvenience.
In view of the aforesaid drawbacks of the conventional spark plug, the inventor has, through repeated studies and experiences and peraonal interest in the art, developed the present invention.
The prime object of the present invention is to provide a spark plug with a ring-shaped ground electrode to generate a slope type of discharging spark. Since the ground electrode forma a round frame over the center electrode, there will, upon explosion taking place, be a high speed air stream to pass through the gap between the electrodes to clean the carbonized deposits off out of the round frame, i.e., something like a washing effect to prevent from generating granular carbonized deposits.
Therefore, the prime feature of the present invention is the round frame on the ground electrode; the round frame has a gap, and the inner diameter of the round frame ia longer than that of the center electrode so as to generate a slope type of discharging spark.
An embodiment of the invention is described by way of example with reference to drawings attached as followas

Fig. 1 illustrates a partial sectional view of a conventional spark plug.
fig. 2 is a bottom view of the spark plug shown in Fig. 1.
Fig, 3 is a partial side and sectional view of the spark plug with a ring-shaped ground electrode in the present invention.
fig. 4 is a bottom view of the spark plug shown in Fig. 3.
Fig. 5 is a bottom view of another embodiment of the spark plug with a ring-shaped ground electrode in the present invention.
Fig. 6 is a bottom view of a still another embodiment of the spark plug with a ring-shaped ground electrode in the present invention.

Referring to Fig. 1 and 2, there ie shown a conventional spark plug, which mainly comprises a center electrode 8 and a ground electrode 9. The center electrode 8 is surrounded with insulator 2 with filling stuffs 3 therein. The top is provided with a terminal 1; outside the insulator 2, there is mounted a ground electrode 9, which extends under the tip of the center electrode 8 with a given spark gap 10. The bottom end of the center electrode 8 is a flat and smooth surface 12 without any crossed threads. Upon a spark taking place in the spark gap, there will be a rectengle-shaped discharge 11. Since the ground electrode 9 is a solid piece, a carbonized deposit as a result of sparking is usually deposited on the discharging surface of the ground electrode 9; that deposita may cause abnormal ignition.
Referring to Fig. 3 and 4, there is shown the ring-shaped ground electrode and the canter electrode of the present invention, in which the bottom end of the center electrode 21 ie provided with crossed threads 23, while the end of the ground electrode 22 is designed into a round frame 24 with a gap 25 to open a portion of the round frame that is opposite to the ground electrode 22. The inner diameter of the round frame 24 is longer than that of the center electrode 21. There is a spark gap 26 between the center electrode 21 and the ground electrode 22. In ignition, the spark in the spark gap 26 becomes a slope type of spark 27. During explosion, there is a high speed air stream to flow through the spark gap 26. In that moment, the carbonized deposits caused by the sparks will flow, together with the air stream of exploaion, out of the round frame 24 without being deposited on the discharge surface of the ground electrode; in other words, a washing effect is provided in the spark plug. The gap 25 is used for preventing the temperature of the ground electrode 22 from being into focus to form a blockade to temperature circulation so as to have the high temperature of the ground electrode transmitted to a radiator promptly.
Referring to Fig. 5, there is shown another embodiment of the present invention, which includes a center electrode 31 and a ground electrode 33 with crossed threads 32, but the inner periphery of the round frame of ground electrode 33 in provided with a number saw teeth 34.
Referring to Fig. 6, there is shown a still another embodiment of the present invention, which includes a center electrode 41 with crossed threads 42 on top, and a ground electrode 43 furnished with several salient lugs 44 along the inner periphery of the round-frame.
According to the aforesaid descriptions, the improved portion of a spark plug in the present invention is merely limited to the ground electrode, but that limited improvement will surely solve the carbonized deposit problem to an expected extent, i.e., it is deemed as being an advanced and practical spark plug without doubt. Since there has been no similar product being found in some relative information and in the markets both domestically and abroad, its novelty may conform with the requirments of the patent law.
The aforesaid drawings are merely served as embodiment of the present invention, but should not be construed as a limit to this invention. Any embodiment made by a person skilled in the art without deviating from the concept and spirit of this invention, even with minor modification in accordance with the structure and features what are claimed in the claims of this invention, should be deemed as being within the scope of this invention.

Claims

1. A spark plug with a ring-shaped ground electrode, comprising:

a center electrode, which may be refered to as the first electrode in said spark plug;

a ground electrode, of which one end is mounted on the spark plug body, and which way be referred to as the second electrode, and between said first and second electrodes there is a spark gap; and the main feature of said spark plug is that the discharge surface of said ground electrode is designed into a ring shape, i.e., a round frame; and upon sparking and explosion, a high speed air stream will blow the carbonized deposits out of the hollow core of the round frame of said ground electrode without being deposited on the discharge surface of the electrodes so as to increase the ignition efficiency.

2. A spark plug with a ring-shaped ground electrode as claimed in claim 1, wherein said round frame has a gap, by which the high temperature generated during explosion will not focus to the ground electrode; i.e., the heat being dissipated through a radiation board promptly.

3. A spark plug with a ring-shaped ground electrode as claimed in claim 1, wherein the hollow core portion of said round frame of the ground electrode may be a general circle, a saw-tooth-shaped circle, or a circle with several salient lugs so as to increase the discharging paths of the sparks between electrodes.

4. A spark plug with a ring-shaped ground electrode constructed and arranged substantially as herein described with reference to any of the figures of the drawings.