JPH0616453Y2 - Temperature measuring spark plug - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a temperature measuring spark plug having a thermocouple built in the center electrode for measuring the temperature of the center electrode of the spark plug operating in an internal combustion engine. It is about.

(Prior Art) Designers of internal combustion engines and manufacturers of spark plugs often want to know the temperature of the center electrode of the spark plug during operation in order to analyze combustion in the engine and select an optimum applicable plug. If the temperature of the center electrode is too low, carbon deposits accumulate and the ignition performance deteriorates. If the temperature is too high, preignition occurs before normal spark ignition. Therefore, in order to select a plug suitable for the internal combustion engine, a temperature measuring spark plug is used to measure the center electrode tip temperature. An example of such a temperature measuring spark plug is shown in FIGS. 2 and 3. In FIG. 2, reference numeral 1 is a metal shell, an outer electrode 2 is provided at the tip, 3 is a ceramic insulator, and a center electrode 4 is held in its inner hole with its tip protruding. The center electrode 4 consists of a metal pipe with a closed tip, and a thermocouple 5 (mainly CA
Thermocouple) is built in. 5-1 is a temperature measuring contact of the thermocouple 5, which is embedded in the tip portion of the center electrode 4 and is 5-2 and 5-3.
Are, for example, chromel wire and alumel wire forming a pair of thermocouple 5. At the rear end of the insulator 3, a high voltage terminal 21 electrically joined to the center electrode 4 and a thermocouple terminal 22 composed of a bipod terminal connected to both wires 5-2 and 5-3 of the thermocouple 5. The connection head 23 provided with is attached.

FIG. 3 is another conventional example, and (a) is a front view of only a main part, and is omitted since the other parts are the same as FIG. 2, and (b) shows (a). It is a top view seen from above. In the figure, 33 is a connection head provided at the rear end of the plug, which is electrically joined to the center electrode and has a high-voltage terminal 31 and a thermocouple terminal.
32-1 and 32-2 are provided.

(Problems to be solved by the invention) Bacterial automobile engines are becoming more electronically controlled and more are being controlled by a computer. However, when temperature is measured with a conventional plug as shown in FIG. 2, The noise emission level increases because the terminal part is long,
In some cases, the computer malfunctions and the engine does not work well, or when a computer is used for measurement, the measurement data may or may not be erroneous due to the above noise. In addition, since the high voltage terminal and the thermocouple terminal are separately taken out, and since they are long, it is difficult to handle the plug when attaching to and detaching from the engine, and it is sometimes necessary to use a special plug wrench. Further, in the case of the conventional example as shown in FIG. 3, when connecting the shield cap for connecting the power cord or the like to the connecting head, it is troublesome to align the opposing terminals between them, which is troublesome. Is bad.

(Means and Actions for Solving the Problem) The present invention has been made in view of the above circumstances, and is a coaxial circuit including a high-voltage contact for a center electrode and a pair of contacts for a thermocouple. Type connection head with 3-pole plug,
The present invention provides a temperature measuring spark plug provided at an end of an insulator. With such a structure, the length of the entire plug can be shortened, the mounting on the engine is easy and the handling is easy, and the directionality of the plug is lost, so that the shield cap can be mounted easily. At the same time, noise emission is reduced. A coaxial three-pole jack may be used instead of the coaxial three-pole plug.

(Embodiment) FIG. 1 is an enlarged vertical cross-sectional view of an essential part of an embodiment of a temperature measuring spark plug according to the present invention. Except for this essential part, other parts are similar to FIG. Was omitted. In FIG. 1, 6 is a coaxial type three-pole plug, 7 and 8 are thermocouple contacts connected to both lines 5-2 and 5-3 of the thermocouple, and 9 is a high voltage terminal. It is a contact for high voltage. The contacts 7, 8 and 9 are coaxially arranged with an insulator interposed therebetween. At the end of the center electrode 4, there is a threaded portion 4-
1 is formed, and the high-voltage contact 9 is electrically and mechanically connected to the center electrode 4 via the connection fitting 10. 3 is a ceramic insulator as in FIG. It should be noted that a coaxial three-pole jack can be used instead of the coaxial three-pole plug.

(Effect of the device) Since the temperature measuring spark plug according to the present invention has the end structure as described above, the total length of the plug can be shortened, so that the noise emission is reduced. It is effective, eliminates the malfunction of the computer as mentioned above, and because it is a coaxial type three-pole plug, there is no directionality of the plug and it is easy to install the shield cap and workability is improved, and like the DOHC engine etc. Even if the plug attachment part is a deep hole, it can be easily attached and detached.

[Brief description of drawings]

FIG. 1 is an enlarged vertical sectional view of an essential part of an embodiment of a temperature measuring spark plug according to the present invention, FIG. 2 is a crushed sectional view of a conventional temperature measuring spark plug, and FIG. 3 is a temperature measuring method of another conventional example. (A) of the spark plug is a front view of a main part, and (B) is a plan view of the spark plug seen from above. 5: Thermocouple, 6: Coaxial three-pole plug, 7, 8: Thermocouple contactor, 9: High voltage contactor.

Claims (1)

[Scope of utility model registration request] 1. A thermometry spark plug for measuring a temperature of a tip of a center electrode by incorporating a thermocouple in a vertical hole of the center electrode, wherein a high-voltage contact for the center electrode and a pair of contacts for the thermocouple. A temperature measuring spark plug provided with a connection head having a coaxial three-pole plug consisting of.