DE7001121U - SPARK PLUG WITH THERMOCOUPLE AND CONNECTING DEVICE. - Google Patents

Description

Attachment to
Utility model registration

Beru-Werk Albert Ruprecht, Ludwigsburg, Wernerstr.

Spark plug with thermocouple and connection device .

The innovation concerns a spark plug that has a thermocouple to measure the temperature at the insulator base and with a device for making the electrical connections is equipped.

The type most commonly used to date for temperature measurement purposes has the thermocouple through the hollow center electrode passed through and welded or soldered with their end protruding into the combustion chamber.

This construction has the disadvantage that the thermocouple, the measuring lines and the measuring instrument are connected to the ignition voltage, lie and cause an additional capacitive load on the ignition system as well as a considerable amount of insulation for the parts belonging to the measuring device. Also can the interference waves originating from the spark of the candle cause great difficulties when this z. B. the falsify information supplied to an electronic control unit of a gasoline injection system, so that the fuel is allocated in an uncontrolled manner.

Spark plugs are already known in which the two legs of the thermocouple in the insulator are fine Grooves are cemented along the edge of the bore of the center electrode and the hot soldering point in the insulator foot is close

Jtmdttrth its end face, but leave the aforementioned

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Do not eliminate disadvantages or only remove them insecurely, since there is a risk of poor cementing or crumbling the putty comes into contact with the thermocouple and the center electrode or through out of the fuel Lead precipitation forms conductive bridges between them, which also falsify the measurement result can be. Since spark plug cement is usually porous, this design prevents flashovers from the center electrode For this reason alone, do not exclude the thermocouple.

In order to avoid the disadvantages described, according to the innovation, the thermocouple is at least of the height of the inner sealing ring on and including its hot solder point directly into the tightly burned material embedded in the ceramic insulator, d. H. surrounded by this directly or only through a narrow air gap separated from him.

To ensure particularly reliable electrical insulation of the thermocouple legs from the center electrode and compared to the ground candle steel body and around to achieve an absolutely hermetic seal against the ingress of highly compressed combustion gases the legs of the thermocouple made of metallic materials whose melting points are higher than the sintering temperature the ceramic mass of the insulator, and are molded into this with a small distance from each other before firing in the furnace, so that after the fire they are embedded all around in the tightly burned insulator.

Through this choice of materials and manufacturing method, a new spatial shape is obtained, which the heat transfer to the A hot solder joint favors and, even in the thin insulator foot part, there is still sufficient wall thickness for the insulation enables.

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The innovation · is in the drawing m example one High-voltage spark plug with thermocouple and mounted connection head and plug in longitudinal section (Fig. 1) and illustrated in the partially cut-away side view (Fig. 2).

The insulator 1 of the spark plug Z is by means of the crushed powder pack 2, the inner sealing ring 3 and the flange 4 built gas-tight in the candle steel body 5 and has a central, stepped bore 6, in which the center electrode 7 is inserted with its head 8 and the connecting bolt provided with thread 9 and tip 10 is cemented. The electrically conductive connection between the connecting bolt 11 and the center electrode 7 takes place through a metal-containing powder seal 12, and the sparkover takes place in the gas space between the center electrode 7 and the measuring electrode 13 instead. On the from the insulator 1 protruding part of the connecting bolt 11 is the hollow cylindrical insulating piece 14 of the connection head A screwed onto which an insulating material plug IS can be plugged in for the purpose of establishing the electrical connection to the ignition distributor or ignition generator (not shown) by means of the ignition cable 16 reinforced with a contact piece 15 and the electrical connection of the both legs 17 a and 17 b of the thermocouple TE with the cold solder joint (not shown) or the (also not shown) measuring instrument, which has the plug · - pins 18 a and 18 b, the connector sleeves 19 a and 19 b and the compensation lines 20 a and 20 b takes place. The two legs 17 a and 17 b of the thermocouple TE are on its upper part in a, z. B. made of silicone rubber insulating compound 21 embedded, which also includes the lower Part of the insulating piece 14 of the connection head A and the upper part of the plug insulator 1 surrounds and the overturning prevents the ignition voltage on the thermocouple.

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The Thenao legs 17 α and 17 b are then guided along the insulator shaft 1 a, then passed through a ceramic double capillary tube 22 and at least from the height of the inner sealing ring 3 to about 1 nm behind the insulator face 23, the hot soldering point 24 is embedded gas-tight and electrically insulated directly in the ceramic material of the insulator 1, as indicated by dots. From the "beiAea Solder parts "24 are the two thin wires that form the thermo legs 17 a and 17 b, together vtndntlit The ceramic double capillary tube 22 lies in a bore 25, which above the candle body * B in the Insulator 1 penetrates and its collar 26 crosses.

The installation of the thermocouples TB threaded into the finished ceramic double capillary tube 22 Isolator 1 takes place in the manner described below, which, compared to other possible types of execution, is distinguished by its simplicity of manufacture:

The isolator shape (green part) is at around 1000 ° C burns and thus has a higher strength. Dana «Earth those around the loss of burning and around a small one Addition of an enlarged bore Γ5 and an adjoining hat f (in the dotted Tell ties insulator) made. The part 27 of the thermocouple T1 protruding from the double capillary tube 22, together with the half soldering point 24, is inserted into this Met by means of a pulpy kerasdi

asee - essentially the same as that of the isolator. Cm also provides the necessary cavity for to compensate for the shrinkage, the two get Leg of the thermocouple dead their embedding in said mat an enreceen coating aas varnish, Synthetic resin or some other organic mass »which

volatilized in the sharp fire, whereas that in the groove Ceramic mass slurried around the thermo legs sintered together gas-tight with that of the pre-fired insulator molding and the thermocouple electrically insulated. The thermocouples used in the ceramic masses customary for spark plug insulators are pairings of platinum and Platinum rhodium or platinum rhodium alloys of different compositions are suitable. Before installing the isolator 1 An X-ray picture is taken in the candle steel body for control purposes and a measuring sheet is made for that of the thermocouple created voltages emitted at the different temperatures.

The electrical connection of the spark plug and its thermocouple is made by attaching the insulating plug IS on the connection head A, the former with its protruding contact piece 15 in the hollow cylindrical insulating piece 1%> of the connection head A engages. This type allows the overall height by filling the gap between the connection head A and the insulating material plug engaging in this IS with a liquid or pasty insulating medium, e.g. B. Oil to reduce (not shown).

13. 1. 70

PAT / I / ue

700Π21

Claims (6)

Protection claims 1. With a thermocouple for measuring äer temperature at the insulator and preferably also with a device for making the electrical connections equipped spark plug, characterized in that the thermocouple (TE, 27) at least from the height of the inner sealing ring (3) on and including its hot soldering point (24) is embedded directly in the tightly burned material of the ceramic insulator (1), ie it is directly surrounded by it or only separated from it by a narrow air gap. 2. Equipped with a thermocouple spark plug according to claim 1, characterized in that the legs (17 a, 17 b) of the thermocouple (TE) consist of metallic materials whose melting points are higher than the sintering temperature of the ceramic mass of the insulator (1), and that they are molded into this prior to firing in the furnace at a distance from one another and including the hot soldering point, in such a way that they are subsequently embedded all around in the tightly fired insulator (1). 3. Equipped with a thermocouple spark plug according to claims 1 and 2, characterized in that its thermocouple (ΤΈ) containing insulator (1) is obtained by prebaking the insulator molding at about 1000 ⁰ C, by incorporating a bore (25) and a Groove (Vm punhtAnirt gogelchniBiten part), by forging the part (27) of the thermocouple (T2) protruding from a double capillary tube (22) inserted into said bore into said groove by means of a porous ceramic mass of essentially the same or similar composition as that of the insulator and by firing the thus prepared insulator molding at sintering temperature. -2- 700112 -2- 4. Equipped with a thermocouple spark plug *: ■ according to claims 1 and 2, characterized in that the two legs (17 a and 17 b) of the thermocouple (TE) above their directly i'i the ceramic insulator (1) embedded part (27; passed through a ceramic double capillary tube (22), then guided along the insulator shaft (1 a) and at the height between the insulator (1) and the insulating piece (14) of the connection head (A) in a heat-resistant insulating compound (21), e.g. B. made of silicone rubber, are embedded. 5. Equipped with a thermocouple and with a device for making the electrical connection spark plug according to one or more of the preceding claims, characterized in that the insulating material plug (IS) with its preferred contact piece (15) in the hollow cylindrical insulating piece (14) of the connection head ( A) intervenes. 6. Equipped with a thermocouple and with a device for making the electrical connection spark plug according to claim 5, characterized in that the gap between the hollow cylindrical insulating piece (15) of the connection head (A) and the insulating plug (IS) engaging in this with a liquid or pasty insulating medium, e.g. B. Oil is filled.