JP2003521118A - Heat-resistant passive resistance element for temperature measurement in passenger and utility vehicles - Google Patents

Abstract

(57) [Summary] A heat-resistant passive resistance element for temperature measurement is proposed, in which an insulating layer (9; 10) substantially existing inside and two ceramic composite structures existing outside are proposed. A conductive layer (8) made of a material, the conductive layer is connected at the tip (11) of the resistance element, and the ceramic composite structure is made of trisilicon tetranitride, metal silicide and yttrium oxide or tetranitride. three silicon encompasses matrix phase composed of metal silicide and _{Si x O y C z N w} , the time x is 1 to 2, y is 0-2, z is 0-2, and w is 0-2 means. Furthermore, a combination element (3) comprising a resistance element and, for example, a glow plug is proposed.

Description

Detailed Description of the Invention

The present invention relates to a heat resistant passive resistance element for temperature measurement in passenger vehicles and utility vehicles. The invention further relates to a combination element for use in the combustion chamber of an internal combustion engine, which combination comprises the resistance element and the functional element.

Prior Art Heat-resistant materials used for temperature measurement in the operating range up to 1400 ° C. are mechanically unstable and therefore generally cannot be used as self-supporting temperature sensitive elements.
They are therefore mounted in the protective tube or on or between the substrates. Most often these are ceramic substrates. Known temperature sensors suitable for exhaust gas are generally Pt / P
A thermoelectric element composed of a precious metal wire made of tRh or Ni / CrNi, the connecting legs of which are insulated from each other in a ceramic tube, the contacts of which are provided by a metal jacket or a ceramic jacket or by a metal plug of a glow plug. It is protected by welding in the cover. Furthermore, temperature sensors configured as thick-film or thin-film elements are known, in which case the temperature-sensitive functional layer is vapor-deposited or sintered on or between the substrates. This causes a reliable deactivation of the thermoelectric element by the respective support material.

Measuring the temperature during combustion in the combustion chamber of an internal combustion engine is even more difficult. Due to the arrival at the combustion chamber, it is often not possible to provide additional openings for temperature sensors, especially in modern 4-valve direct injection engines.

Furthermore, the temperature to be measured or the temperature interval from −40 to 1400 ° C. imposes very high demands on the corresponding temperature sensor in the context of a vigorous atmosphere in the form of hot air.

OBJECT OF THE INVENTION It is therefore an object of the invention to provide a mechanically stable, self-supporting resistance measuring device which is heat resistant up to very high temperatures of 1400 ° C. It enables the measurement of the exhaust gas temperature at the exhaust gas port or the combustion chamber temperature of PKW engines and NKW engines in the operating range of -40 to 1400 ° C. In the latter case, the temperature measurement should be realized via one of the openings present in the combustion chamber.

According to the present invention, the above-mentioned problems are solved by a heat-resistant passive resistance element for temperature measurement, which is composed of two conductive layers consisting of an insulating layer existing inside and a ceramic composite structure existing outside. A conductive layer connected to one another at the tip of the resistive element, the ceramic composite structure comprising trisilicon tetranitride, metal silicide and yttrium oxide or trisilicon tetranitride, metal silicide and encompasses Si _x O _y C _z N _w consists matrix phase, its time x 1 to 2, y is 0-2, z is 0-2 and w means 0-2.

In an advantageous aspect of the invention, the insulating layer present therein comprises a ceramic composite structure.

In this case, the composition of the insulating component and the conductive component is preferably only slightly different, so that it is possible to co-sinter or simultaneously pyrolyze the composite material. Regarding sintering, it is shown in EP 0 421 428 A1 and DE 19538695 A1.

In a simplified variant, the inner insulating layer of composite material leaves voids for insulation.

The ceramic composite structure of the resistance element according to the invention is preferably 30 to 70% by weight.
Of _Si 3 _N 4, _25~65 wt% of _MSi 2 (M is Mo, Nb, a W or Ti), from 0 to 5 mass% _Al 2 _{O 3} and 2-9% by weight of _Y 2 _{O 3} contains.

Similarly, the matrix phase of Si _x O _y C _z N _w in the ceramic composite structure may be a thermal decomposition product of one or more organosilicon compounds. Suitable compounds are polysiloxanes such as NH2100 from Huels and polysilazanes such as NCP200 from Nichmen Incorp. Of Japan.

Composites based on trisilicon tetranitride with fillers of the metal silicate MSi ₂ are thermally and mechanically durable and by adding the specified proportions of the corresponding filler constituents. , Having an electrical resistance with a positive temperature coefficient that can be adjusted depending on the proportion added. This allows a combination of properties, for example in which rapidly heated glow plugs are produced, as described in EP 0 421 428 A1 and DE 195 38 695 A1.

In an advantageous aspect of the invention, the tip of the resistive element is tapered. The resistance of the sensor can be adjusted by tapering the conductive area of the tip. The length of the tapered region defines the position of temperature measurement. The electrical resistance of the conductive composite material at the tip is modified over some large internal structure by modified mixing with the material in the lead wire, which is interpreted as the central body of the resistive element, which results in thermal / mechanical Not affected by characteristics. This is very important, especially in the case of unsupported embodiments.

The high mechanical strength of the composite agent makes it possible to form a self-supporting resistive element, which is free-standing or mounted in a suitable case like a ceramic glow plug. It can be installed directly in the exhaust gas port of a passenger vehicle or a utility vehicle. Incorporation of the temperature-sensitive material directly into the area to be measured, without a protective cap and without a support, guarantees a rapid resistance change of the sensor and thus advantageously a temperature measurement which is not sufficiently slow To do.

Due to the good oxidative stability of the matrix materials and the deposition compounds used, these materials are stable up to 1400 ° C. both in oxidizing and reducing atmospheres.

These materials have a nearly linear increase in electrical resistance with increasing temperature in the range of -40 to 1400 ° C., so that temperature measurement in the entire range is feasible.

As an application example of the heat-resistant resistance element according to the present invention for temperature measurement at the exhaust gas port of passenger vehicles and utility vehicles, a starting catalyst and a main converter in a lean burn concept engine, for example, a gasoline direct injection engine are given. Exhaust gas temperature measurement during The high mechanical strength of the composite ceramics, which enables a self-supporting construction of very little space requirements, advantageously enables a particularly flexible arrangement of the temperature sensor in a suitable position in the exhaust gas. In addition to the front and back of the catalyst, it can be mounted directly inside the catalyst for specific detection purposes.

In a particularly advantageous manner, the resistance element according to the invention is combined with a functional element projecting into the combustion chamber of an internal combustion engine. The functional element may be a starting aid, an injection nozzle or a valve. The starting aid may be a glow plug.

As mentioned above, temperature measurement can now be realized via openings present in the combustion chamber of PKW or NKW engines.

A resistance element composed of the above-mentioned materials, in combination with a functional element, acts as a glow plug of the rapid heating type on the one hand under voltage application, and on the other hand changes depending on the temperature. With electrical resistance as the measurement signal, during active energization,
It can therefore also be used for temperature measurement during the heating or glowing phase, as well as in the passive, ie currentless, resting phase. The high mechanical strength of the composite agent allows the self-supporting composite element to be machined, which is mounted unsupported in a suitable case and mounted directly on the passenger vehicle instead of the conventional glow plug. And may be mounted in the combustion chamber of a utility vehicle. Introducing the temperature-sensitive material directly into the area to be measured, without protective cap, in this case advantageously guarantees a rapid resistance change of the sensor and thus a temperature measurement that is not sufficiently slow. Guarantee.
The sensitivity of the sensor element can be adjusted by the ratio of lead wire resistance to sensor tip resistance.

An example of an application for the new combination element is combustion chamber temperature measurement in a diesel injection engine. A particular advantage is that with the introduction of the function the temperature sensor and the glow do not require any additional space requirements. The combustion temperature can be considered as a quantity for the combustion process.

Drawings FIG. 1 shows a cross-sectional view of a heat-resistant passive resistance element for measuring temperature in an exhaust gas port of a passenger vehicle or a utility vehicle.

FIG. 2 shows a cross-sectional view of a heat resistant passive combination element in the combustion chamber of a PKW or NKW engine.

FIGS. 3 and 4 show heat-resistant passive resistance elements according to the invention in different embodiments.

In FIG. 1, a self-supporting PTC temperature sensor 4 made of composite ceramic is
It rushes into the exhaust gas port 6 including the catalyst. The direction of the exhaust gas flow 7 is shown in the direction of the arrow. At the thickened end, the temperature sensor 4 is fixed with a rotary screw through the case 2. Here, the control device or the measurement electric equipment and the evaluation electric equipment were connected. The temperature-dependent resistance measured by the measuring device can be adapted by means of a balanced electric appliance (Ausgleichselektronik) 1 of the standard-Pt-100 or Pt-200-element characteristic using a resistance measuring device or connector.

In FIG. 2, a combination element 3 including a glow plug and a temperature sensor is thrust into a combustion chamber 5 of the engine.

In FIGS. 3 and 4, the conductive composite material 8 has a PTC-resistor R ₁ . Figure 3
In, the insulating composite material 9 has an electrical resistance R ₂ , where R ₂ ≧ 10 ⁸ ·
R ₁ . The insulating composite material 9 has been replaced by a void 10 (FIG. 4) having an electrical resistance R ₂ .

The PTC-conductive composite material with resistance R ₃ (R ₃ ≧ 10 ² · R ₁ ) forms the tip 11 of the resistance element according to the invention. The tapering of the conductive area on the tip 11 allows the electrical resistance of the combination element to be adjusted. The length of the tapered area is
The function as a glow plug defines the position of a region heated during energization, and the function as a temperature sensor defines the position for temperature measurement.

[Brief description of drawings]

FIG. 1 shows a cross-sectional view of a heat-resistant passive resistance element for temperature measurement in an exhaust gas port of a passenger vehicle or a utility vehicle.

FIG. 2 shows a cross-sectional view of a heat resistant passive combination element in the combustion chamber of a PKW or NKW engine.

[Figure 3]   FIG. 3 shows a heat resistant passive resistance element according to the present invention.

[Figure 4]   FIG. 4 shows a heat resistant passive resistance element according to the present invention.

[Explanation of symbols]

1 balanced electric equipment, 2 cases, 3 combination elements, 4 temperature sensors,
5 combustion chamber, 6 exhaust gas port, 7 exhaust gas flow, 8 conductive composite material,
9 Insulating composite material, 10 Void, 11 Tip,

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02P 19/02 311 H01L 37/00 H01L 37/00 C04B 35/58 102K (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE, TR), AU, BR, CA, CN, CZ, HR , HU, ID, IN, JP, KR, MX, PL, RU, SG, SI, SK, US, ZA (72) Inventor Jens Stephan Schneider United States South Carolina Anderson Quail Hollow Road 409 (72) Inventor Wolfgang Dresdler Feijingen, Federal Republic of Germany Nünstein Steinhardenweg 7 (72) Inventor Friederike Lätner Germany Gerlingen Immermannstraße 24 (72) Inventor Ulrich Eisele Germany Schütt Stuttgart Becklerstraße 6 Be (72) Inventor Frank Stagnmeier Germany Republic Meklingen Ellen-Kaiweg 8 (72) Inventor Volker-Roth Acker Germany Beitichheim-Bissingen Bromberger Strasse 24 (72) Inventor Christoph Koeln Germany Aspach Wilhelmstraße 5 (72) Inventor Thomas Moser Federal Republic of Germany Schwieberdingen Helen Wiesenweg 7F Term (reference) 3G066 AD12 BA44 BA53 CD18 CD25 4G001 BA03 BA09 BA32 BA48 BA49 BA51 BA56 BA77 BB03 BB09 BB32 BB48 BB49 BB51 BB56 BC46 BD22 BE15 5E034 BA09 BB01 BC17 BC20 DB03

Claims (12)

[Claims] 1. A heat-resistant passive resistance element for measuring temperature, comprising:
Insulating layer (9; 10) existing inside and ceramic composite structure existing outside
Having two conductive layers (8) consisting of a conductive layer at the tip (11) of the resistive element.
The layers are bonded together and the ceramic composite structure is trisilicon tetranitride, metal
Silicide and yttrium oxide or trisilicon tetranitride, metal silicide and Si_xO _y C_zN_wA matrix phase consisting of x, where x is 1-2, y is 0-2, z
Is a heat resistance for temperature measurement, characterized in that 0 means 0 to 2 and w means 0 to 2
Passive element. 2. Resistive element according to claim 1, characterized in that the insulating layer (9) present therein has a ceramic composite structure. 3. The ceramic composite structure comprises 30 to 70% by mass of Si ₃ N ₄ ,
_MSi 2 of 25 to 65 wt% includes (M is Mo, Nb, W, a Ti), from 0 to 5 mass% _Al 2 _{O 3} and 2-9% by weight of _Y 2 _{O 3,} claim 1 Alternatively, the resistance element according to the item 2. 4. The matrix phase comprising Si _x O _y C _z N _w in the ceramic composite structure is a pyrolysis product of one or more organosilicon compounds.
The resistance element described. 5. The resistance element according to claim 4, wherein the organosilicon compound is polysiloxane or polysilazane. 6. An insulating layer (10) present inside is a void.
6. The resistance element according to any one of 1 to 5. 7. The resistance element according to claim 1, wherein the tip (11) is tapered. 8. The resistance element according to claim 1, which is mounted in a case. 9. The resistance element according to claim 1, which is associated with a functional element that rushes into the combustion chamber (5) of an internal combustion engine. 10. The resistance element according to claim 9, wherein the functional element is a starting assist device, a direct injection nozzle or a valve. 11. The resistance element according to claim 10, wherein the starting assist device is a glow plug. 12. Use of the resistance element according to claim 1 in an exhaust gas port (6) of a passenger vehicle or a utility vehicle.