WO1992001916A1 - Pressure sensor for determination of the pressure in a combustion chamber of an internal-combustion engine - Google Patents

Pressure sensor for determination of the pressure in a combustion chamber of an internal-combustion engine Download PDF

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Publication number
WO1992001916A1
WO1992001916A1 PCT/DE1991/000530 DE9100530W WO9201916A1 WO 1992001916 A1 WO1992001916 A1 WO 1992001916A1 DE 9100530 W DE9100530 W DE 9100530W WO 9201916 A1 WO9201916 A1 WO 9201916A1
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WO
WIPO (PCT)
Prior art keywords
pressure
pressure sensor
hybrid
carrier
sensor according
Prior art date
Application number
PCT/DE1991/000530
Other languages
German (de)
French (fr)
Inventor
Walter Benedikt
Manfred Vogel
Werner Herden
Johann Konrad
Wolfgang Schmidt
Josef Tosch
Matthias Kuessel
Original Assignee
Robert Bosch Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Priority to KR1019920700307A priority Critical patent/KR920702493A/en
Publication of WO1992001916A1 publication Critical patent/WO1992001916A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • G01L9/0041—Transmitting or indicating the displacement of flexible diaphragms
    • G01L9/0051—Transmitting or indicating the displacement of flexible diaphragms using variations in ohmic resistance
    • G01L9/0052—Transmitting or indicating the displacement of flexible diaphragms using variations in ohmic resistance of piezoresistive elements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • G01L9/02—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in ohmic resistance, e.g. of potentiometers, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning
    • G01L9/06—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in ohmic resistance, e.g. of potentiometers, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning of piezo-resistive devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G01L1/2287—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges constructional details of the strain gauges
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L23/00—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid
    • G01L23/08—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid operated electrically
    • G01L23/18—Devices or apparatus for measuring or indicating or recording rapid changes, such as oscillations, in the pressure of steam, gas, or liquid; Indicators for determining work or energy of steam, internal-combustion, or other fluid-pressure engines from the condition of the working fluid operated electrically by resistance strain gauges

Definitions

  • Pressure sensor for pressure detection in the combustion chamber of internal combustion engines
  • the invention is based on a pressure transmitter according to the preamble of claim 1.
  • a pressure transmitter known from DE-OS 31 25 640.6
  • the piezoresistive measuring elements such as thick-film resistors made of cermet, contactiv, plastic or platinum, are printed on a carrier.
  • the resistance element and the carrier are arranged as close as possible to the pressure chamber in order to be able to determine the pressure prevailing there.
  • the measurement signal is conducted with the aid of electrical lines to an electronic evaluation circuit arranged outside the housing of the pressure transmitter.
  • the piezoresistive elements and the electronic components have to be connected to one another in a complex manner with the aid of shielded lines.
  • the piezoresistive measuring element Since the piezoresistive measuring element is directly exposed to the pressure, it is also exposed to the high temperatures prevailing in the combustion chamber. The flames spread there at a temperature of approx. 2000 ° C, which can result in tension in the housing. As a result, the pressure signal is falsified by the high temperatures. Furthermore, a pressure sensor is known from EP-OS 85 111 895.0, in which the thick-film resistor is arranged on the bottom of a support. However, this pressure sensor is only intended for determining the pressure in distributor pumps. The high temperatures prevailing in the combustion chamber would also falsify the measurement signal in this embodiment.
  • the pressure sensor according to the invention with the characterizing features of claim 1 has the advantage that the piezoresistive measuring element is relatively far from the combustion chamber and the high temperatures prevailing there, so that the measurement signal is not falsified by the temperatures prevailing in the combustion chamber.
  • the piezoresistive measuring element and the hybrid By arranging the piezoresistive measuring element and the hybrid on the counter bearing of the stamp, standard bonding techniques that have been tried and tested in practice can be used to connect the electronic components and the piezo elements.
  • Various adapted materials can be used as the material for the carrier of the hybrid, which can advantageously also be used at the same time as a carrier for the thick-film resistors and semiconductor components.
  • the hybrid can be printed with the conductor tracks and the contact areas for the piezoresistive effect at the same time.
  • the entire hybrid including the electronic components for signal processing and the piezoresistive elements, can be checked before installation in the sensor housing. This enables simple mounting of the pressure sensor. If the piezoresistive measuring element and the electronic components are on a common carrier and are arranged on the side of the counter-bearing facing the membrane, its overall length can be shortened. If the resistors are pressed in the direction of the current flowing through the resistance layers, a particularly high measurement signal is obtained. This is higher than with conventional solutions in which the resistance is pressed perpendicular to the current direction. It is possible to concentrate the force on a small measuring surface in order to be able to bring about the highest possible pressure for generating the measuring signal.
  • Figure 1 shows a section through a pressure sensor and Figure 2 shows a detail.
  • 10 denotes the housing of a pressure sensor 11 for determining the pressure in the combustion chamber of an internal combustion engine. It has a central, continuous, stepped bore 12.
  • the opening 13 of the housing 10 facing the combustion chamber is closed off by a membrane 14.
  • the membrane 14 is designed as a so-called cap membrane, the edge of the membrane 14 being bent over and being pushed over the end of the shaft 15 of the housing 10.
  • the membrane 14 is firmly seated on the housing, but, in order to ensure mobility of the membrane 14, it is not directly on the End face 16 of the shaft 15.
  • the bending area of the membrane 14 can thereby move freely.
  • the membrane 14 is welded to the shaft 15 in the region of the edge.
  • the membrane 14 is particularly advantageously formed from a superalloy, that is to say from an alloy of, for example, approximately 50% Ni, 20% Cr, 20% Fe.
  • a plunger 18 bears with its one end, which bears against a piezoresistive measuring element 19 with its other end.
  • Piezoresistive measuring elements are to be understood as elements that change their resistance under the action of pressure.
  • Thick film resistors can be used for this purpose, for example. Cermet, contactiv, plastic or platinum etc. can be used as materials for this.
  • the measuring element 19 is printed on the carrier 20 of a hybrid 21.
  • a carrier Under a hybrid, a carrier is normally to be provided with printed circuit parts, such as resistors and conductor tracks, etc., and an IC (integrated circuit), which is placed on the carrier and is connected to the circuit parts, for example by bonding wires.
  • the stamp 18 itself can be made of glass ceramic, in order to ensure good thermal insulation between the membrane, that is to say between the pressure chamber whose pressure is to be determined and the piezoresistive measuring element.
  • the end of the plunger 18 facing the hybrid 21 can be conical, so that its end has approximately the diameter of the measuring element 19. This makes it possible to guide the punch 18 in the bore 12, but on the other hand to limit the area of the pressure transmission to the size of the measuring element 19.
  • the carrier 20 of the hybrid also bears against a counter bearing 22 pressed into
  • the hybrid 21 and the end of the stamp 18 are shown in more detail in FIG. 2.
  • the carrier 20 consists of an Al 2 O 3 substrate layer on which a first contact layer 23 is printed.
  • the first conductor track 23 the piezoresistive resistance layer 24, then the second conductor track 25 is printed on.
  • the end of the stamp 18 is fastened on the second conductor track 25 with the aid of a glass-like mass, in order thereby to enable a uniform introduction of force onto the resistance element 24.
  • the electronic components 28, such as resistors, transistors, etc. are arranged on the carrier 20 of the hybrid 21.
  • the electronic semiconductor components 28 and the conductor tracks are connected by means of bond wires 31.
  • the output of the purification electronics is connected with the aid of a line 32 to an evaluation circuit and control device of the internal combustion engine, not shown, located outside the sensor.
  • a through bore 33 is formed in the counter bearing 22 which runs axially parallel to the bore 1 2 and in which the derivative 32 is guided.
  • the line 27 is fastened in a grommet 34 of the cover 35 closing the bore 12.
  • a segment can also be cut out on the counter bearing 20 for the passage of the line 32.
  • the bore 12 in the area of the electronic components 28 and / or in the area between the counter bearing 22 and the cover 35 is poured out with a casting compound 36.
  • the resistors 24 are printed in the current direction in FIG. 2, a very high-resistance resistor paste having to be used. Compared to conventional arrangements, this results in a larger measurement signal with a constant magnitude of the force introduced.

Abstract

In the pressure sensor (11) disclosed, a sensor element (19) made of piezo-resistive material is located in a housing (10). The resistive films (23, 25) of this piezo-resistive sensor element (19) are compressed in the direction of the current flowing through the films. When very-high-resistance paste is used for the resistive films, it is possible to produce a relatively high measuring signal.

Description

Druckgeber zur Druckerfassung im Brennraum von Brennkraftmaschinen Pressure sensor for pressure detection in the combustion chamber of internal combustion engines
Stand der Technik State of the art
Die Erfindung geht aus von einem Druckgeber nach der Gattung des Anspruchs 1. Bei einem derartigen, aus der DE-OS 31 25 640.6 bekannten Druckgeber sind die piezoresistiven Meßelemente, wie zum Beispiel Dickschichtwiderstände aus Cermet, Contactiv, Plastic oder Platin auf einem Träger aufgedruckt. Das Widerstandselement und der Träger sind möglichst nahe am Druckraum angeordnet, um den dort herrschenden Druck bestimmen zu können. Ferner wird das Meßsignal mit Hilfe von elektrischen Leitungen zu einer außerhalb des Gehäuses des Druckgebers angeordneten elektronischen Auswerteschaltung geführt. Dadurch müssen die piezoresistiven Elemente und die elektronischen Bauteile mit Hilfe von abgeschirmten Leitungen aufwendig miteinander verbunden werden. Da das piezoresistive Meßelement direkt dem Druck ausgesetzt ist, ist es auch den im Brennraum herrschenden hohen Temperaturen ausgesetzt. Die Flammen breiten sich dort mit einer Temperatur von ca. 2000° C aus, wodurch sich Verspannungen im Gehäuse ergeben können. Dadurch wird das Drucksignal durch die hohen Temperaturen verfälscht. Ferner ist aus der EP-OS 85 111 895.0 ein Drucksensor bekannt, bei dem der Dickschichtwiderstand am Boden eines Trägers angeordnet ist. Dieser Drucksensor ist aber nur für die Bestimmung des Drucks in Verteilerpumpen vorgesehen. Die im Brennraum herrschenden hohen Temperaturen würden auch bei dieser Ausführung das Meßsignal verfälschen. The invention is based on a pressure transmitter according to the preamble of claim 1. In such a pressure transmitter known from DE-OS 31 25 640.6, the piezoresistive measuring elements, such as thick-film resistors made of cermet, contactiv, plastic or platinum, are printed on a carrier. The resistance element and the carrier are arranged as close as possible to the pressure chamber in order to be able to determine the pressure prevailing there. Furthermore, the measurement signal is conducted with the aid of electrical lines to an electronic evaluation circuit arranged outside the housing of the pressure transmitter. As a result, the piezoresistive elements and the electronic components have to be connected to one another in a complex manner with the aid of shielded lines. Since the piezoresistive measuring element is directly exposed to the pressure, it is also exposed to the high temperatures prevailing in the combustion chamber. The flames spread there at a temperature of approx. 2000 ° C, which can result in tension in the housing. As a result, the pressure signal is falsified by the high temperatures. Furthermore, a pressure sensor is known from EP-OS 85 111 895.0, in which the thick-film resistor is arranged on the bottom of a support. However, this pressure sensor is only intended for determining the pressure in distributor pumps. The high temperatures prevailing in the combustion chamber would also falsify the measurement signal in this embodiment.
Vorteile der Erfindung Advantages of the invention
Der erfindungsgemäße Drucksensor mit den kennzeichnenden Merkmaien des Anspruchs 1 hat demgegenüber den Vorteil, daß das piezoresistive Meßelement relativ weit vom Brennraum und den dort herrschenden hohen Temperaturen entfernt ist, so daß das Meßsignal nicht durch die im Brennraum herrschenden Temperaturen verfälscht wird. Durch die Anordnung des piezoresistiven Meßelements und des Hybrids auf dem Gegenlager des Stempels können in der Praxis erprobte Standardbondtechniken zur Verbindung der elektronischen Bauteile und der Piezoelemente angewendet werden. Als Material für den Träger des Hybrids, der in vorteilhafter Weise gleichzeitig auch als Träger für die Dickschichtwiderstände und Halbleiterbauteile verwendet werden kann, können verschiedene angepaßte Materialien verwendet werden. Der Hybrid kann in einem Arbeitsgang gleichzeitig mit den Leiterbahnen und den Kontaktflächen für den piezoresistiven Effekt bedruckt werden. Der gesamte Hybrid, einschließlich der elektronischen Bauteile zur Signalaufbereitung und der piezoresistiven Elemente kann vor dem Einbau in das Sensorgehäuse überprüft werden. Dadurch ist eine einfache Montage des Drμcksensors möglich. Befinden sich das piezoresistiven Meßelement und die elektronischen Bauteile auf einem gemeinsamen Träger und sind auf der der Membran zugewandten Seite des Gegenlagers angeordnet, so kann seine Baulänge verkürzt werden. Werden die Widerstände in Richtung des durch die Widerstandsschichten fließenden Stroms gedrückt, so erhält man ein besonders hohes Meßsignal. Dies ist höher als bei konventionellen Lösungen, bei der der Widerstand senkrecht zur Stromrichtung gedrückt wird. Es ist möglich, die Kraft auf eine geringe Meßfläche zu konzentrieren, um einen möglichst hohen Druck zur Erzeugung des Meßsignals bewirken zu können. The pressure sensor according to the invention with the characterizing features of claim 1 has the advantage that the piezoresistive measuring element is relatively far from the combustion chamber and the high temperatures prevailing there, so that the measurement signal is not falsified by the temperatures prevailing in the combustion chamber. By arranging the piezoresistive measuring element and the hybrid on the counter bearing of the stamp, standard bonding techniques that have been tried and tested in practice can be used to connect the electronic components and the piezo elements. Various adapted materials can be used as the material for the carrier of the hybrid, which can advantageously also be used at the same time as a carrier for the thick-film resistors and semiconductor components. The hybrid can be printed with the conductor tracks and the contact areas for the piezoresistive effect at the same time. The entire hybrid, including the electronic components for signal processing and the piezoresistive elements, can be checked before installation in the sensor housing. This enables simple mounting of the pressure sensor. If the piezoresistive measuring element and the electronic components are on a common carrier and are arranged on the side of the counter-bearing facing the membrane, its overall length can be shortened. If the resistors are pressed in the direction of the current flowing through the resistance layers, a particularly high measurement signal is obtained. This is higher than with conventional solutions in which the resistance is pressed perpendicular to the current direction. It is possible to concentrate the force on a small measuring surface in order to be able to bring about the highest possible pressure for generating the measuring signal.
Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen des im Anspruch 1 angegebenen Drucksensors möglich. Advantageous developments of the pressure sensor specified in claim 1 are possible through the measures listed in the subclaims.
Zeichnung drawing
Ausführungsbeispiele der Erfindung sind in der Zeichnung dargestellt und in der nachfolgenden Beschreibung näher erläutert. Die Figur 1 zeigt einen Schnitt durch einen Druckgeber und Figur 2 eine Einzelheit. Embodiments of the invention are shown in the drawing and explained in more detail in the following description. Figure 1 shows a section through a pressure sensor and Figure 2 shows a detail.
Beschreibung des Ausführungsbeispiels Description of the embodiment
In der Figur 1 ist mit 10 das Gehäuse eines Drucksensors 11 zur Bestimmung des Drucks im Brennraum einer Brennkraftmaschine bezeichnet. Es weist eine mittige, durchgehende, abgesetzte Bohrung 12 auf. Die dem Brennraum zugewandte Öffnung 13 des Gehäuses 10 wird Von einer Membran 14 abgeschlossen. Die Membran 14 ist als sogenannte Kappenmembran ausgebildet, wobei der Rand der Membran 14 umgebogen ist und über das Ende des Schafts 15 des Gehäuses 10 geschoben ist. Die Membran 14 sitzt dadurch fest am Gehäuse, liegt aber, um eine Beweglichkeit der Membran 14 zu gewährleisten, nicht direkt an der Stirnseite 16 des Schafts 15 an. Der Biegebereich der Membran 14 kann sich dadurch frei bewegen. Die Membran 14 ist im Bereich des Randes am Schaft 15 angeschweißt. Besonders vorteilhaft ist die Membran 14 aus einer Superlegierung, das heißt aus einer Legierung von zum Beispiel ca. 50 % Ni, 20 % Cr, 20 % Fe ausgebildet. Am mittleren Bereich der Membran 14 liegt ein Stempel 18 mit seinem einen Ende an, der mit seinem anderen Ende an einem piezoresistiven Meßelement 19 anliegt. Unter piezoresistiven Meßelementen sind Elemente zu verstehen, die ihren Widerstandswert unter Druckeinwirkung ändern. In FIG. 1, 10 denotes the housing of a pressure sensor 11 for determining the pressure in the combustion chamber of an internal combustion engine. It has a central, continuous, stepped bore 12. The opening 13 of the housing 10 facing the combustion chamber is closed off by a membrane 14. The membrane 14 is designed as a so-called cap membrane, the edge of the membrane 14 being bent over and being pushed over the end of the shaft 15 of the housing 10. As a result, the membrane 14 is firmly seated on the housing, but, in order to ensure mobility of the membrane 14, it is not directly on the End face 16 of the shaft 15. The bending area of the membrane 14 can thereby move freely. The membrane 14 is welded to the shaft 15 in the region of the edge. The membrane 14 is particularly advantageously formed from a superalloy, that is to say from an alloy of, for example, approximately 50% Ni, 20% Cr, 20% Fe. At the central area of the membrane 14, a plunger 18 bears with its one end, which bears against a piezoresistive measuring element 19 with its other end. Piezoresistive measuring elements are to be understood as elements that change their resistance under the action of pressure.
Hierzu können zum Beispiel Dickschichtwiderstände verwendet werden. Als Materialien können hierzu Cermet, Contactiv, Plastic oder Platin etc. Verwendung finden. Das Meßelement 19 ist auf den Träger 20 eines Hybrids 21 aufgedruckt. Unter einem Hybrid ist normalerweise ein Träger mit aufgedruckten Schaltungsteilen, wie zum Beispiel Widerständen und Leiterbahnen etc. und einem IC (integrated circuit), der auf den Träger aufgesetzt ist und mit den Schaltungsteilen zum Beispiel durch Bonddrähte verbunden ist, zu versehen. Der Stempel 18 selbst kann aus Glaskeramik bestehen, um somit eine gute Wärmeisolierung zwischen der Membran, das heißt zwischen dem Druckraum dessen Druck bestimmt werden soll und dem piezoresistiven Meßelement zu gewährleisten. Das dem Hybrid 21 zugewandte Ende des Stempels 18 kann konisch ausgebildet sein, so daß sein Ende etwa den Durchmesser des Meßelements 19 aufweist. Dadurch ist es möglich, den Stempel 18 in der Bohrung 12 zu führen, hingegen aber den Bereich der Druckübertragung auf die Größe des Meßelements 19 zu begrenzen. Der Träger 20 des Hybrids liegt ferner an einem in die Bohrung 12 eingepreßten Gegenlager 22 an. Thick film resistors can be used for this purpose, for example. Cermet, contactiv, plastic or platinum etc. can be used as materials for this. The measuring element 19 is printed on the carrier 20 of a hybrid 21. Under a hybrid, a carrier is normally to be provided with printed circuit parts, such as resistors and conductor tracks, etc., and an IC (integrated circuit), which is placed on the carrier and is connected to the circuit parts, for example by bonding wires. The stamp 18 itself can be made of glass ceramic, in order to ensure good thermal insulation between the membrane, that is to say between the pressure chamber whose pressure is to be determined and the piezoresistive measuring element. The end of the plunger 18 facing the hybrid 21 can be conical, so that its end has approximately the diameter of the measuring element 19. This makes it possible to guide the punch 18 in the bore 12, but on the other hand to limit the area of the pressure transmission to the size of the measuring element 19. The carrier 20 of the hybrid also bears against a counter bearing 22 pressed into the bore 12.
Der Hybrid 21 und das Ende des Stempels 18 ist in der Figur 2 näher dargesellt. Der Träger 20 besteht aus einer Al2O3-Substratschicht, auf der eine erste Kontaktschicht 23 aufgedruckt ist. In einen nachfolgenden Druckvorgang sind auf die erste Leiterbahn 23 die piezoresistive Widerstandsschicht 24, anschließend die zweite Leiterbahn 25 aufgedruckt. Das Ende des Stempels 18 ist mit Hilfe einer glasartigen Masse auf der zweiten Leiterbahn 25 befestigt, um dadurch eine gleichmäßige Krafteinleitung auf das Widerstandselement 24 zu ermöglichen. Ferner sind auf dem Träger 20 des Hybrids 21 die elektronischen Bauteile 28, wie zum Beispiel Widerstände, Transistoren, etc. angeordnet. Die elektronischen Halbleiterbauteile 28 und die Leiterbahnen sind mit Hilfe von Bonddrähten 31 verbunden. Der Ausgang der Aufbereichtungselektronik ist min Hilfe einer Leitung 32 mit einer nicht dargestellten, außerhalb des Sensors befindlichen AuswerteSchaltung und Steuereinrichtung der Brennkraftmaschine verbunden. Hierzu ist im Gegenlager 22 eine achsparallel zur Bohrung 1 2 verlaufende, durchgehende Bohrung 33 ausgebildet, in der die Ableitung 32 geführt wird. Die Leitung 27 ist in einer Tülle 34 des die Bohrung 12 abschließenden Deckels 35 befestigt. Statt einer BohrungThe hybrid 21 and the end of the stamp 18 are shown in more detail in FIG. 2. The carrier 20 consists of an Al 2 O 3 substrate layer on which a first contact layer 23 is printed. In a subsequent printing process, the first conductor track 23 the piezoresistive resistance layer 24, then the second conductor track 25 is printed on. The end of the stamp 18 is fastened on the second conductor track 25 with the aid of a glass-like mass, in order thereby to enable a uniform introduction of force onto the resistance element 24. Furthermore, the electronic components 28, such as resistors, transistors, etc., are arranged on the carrier 20 of the hybrid 21. The electronic semiconductor components 28 and the conductor tracks are connected by means of bond wires 31. The output of the purification electronics is connected with the aid of a line 32 to an evaluation circuit and control device of the internal combustion engine, not shown, located outside the sensor. For this purpose, a through bore 33 is formed in the counter bearing 22 which runs axially parallel to the bore 1 2 and in which the derivative 32 is guided. The line 27 is fastened in a grommet 34 of the cover 35 closing the bore 12. Instead of a hole
33 kann auch am Gegenlager 20 ein Segment zur Durchführung der Leitung 32 ausgeschnitten sein. 33, a segment can also be cut out on the counter bearing 20 for the passage of the line 32.
Zum Schutz vor schädlichen Umwelteinflüssen, wie z. B. Feuchtigkeit ist die Bohrung 12 im Bereich der elektronischen Bauteile 28 und/oder im Bereich zwischen dem Gegenlager 22 und dem Deckel 35 mit einer Vergußmasse 36 ausgegossen. To protect against harmful environmental influences, such as. B. Moisture, the bore 12 in the area of the electronic components 28 and / or in the area between the counter bearing 22 and the cover 35 is poured out with a casting compound 36.
In der Figur 2 sind die Widerstände 24 in Stromrichtung gedruckt, wobei eine sehr hochohmige Widerstandpaste verwendet werden muß. Dadurch erhält man gegenüber herkömmlichen Anordnungen ein größeres Meßsignal bei gleichbleibender Größe der eingeleiteten Kraft. The resistors 24 are printed in the current direction in FIG. 2, a very high-resistance resistor paste having to be used. Compared to conventional arrangements, this results in a larger measurement signal with a constant magnitude of the force introduced.

Claims

Ansprüche Expectations
1. Druckgeber (11) zur Druckerfassung im Brennraum von Brenhkraftmaschinen, insbesondere von Kraftfahrzeugen, in dessen Gehäuse (10) ein aus einem piezoresistiven Werkstoff bestehendes Sensorelement (19) angeordnet ist, dadurch gekennzeichnet, daß die Widerstandsschichten (23, 25) des piezoresistiven Elements (19) in Richtung des durch die Widerstandsschichten fließenden Stroms gedrückt sind. 1. Pressure sensor (11) for pressure detection in the combustion chamber of internal combustion engines, in particular of motor vehicles, in the housing (10) of which a sensor element (19) consisting of a piezoresistive material is arranged, characterized in that the resistance layers (23, 25) of the piezoresistive element (19) are pushed in the direction of the current flowing through the resistance layers.
2. Druckgeber nach Anspruch 1, dadurch gekennzeichnet, daß zwischen einer Membran (14) und dem Sensor ein Stempel (18) angeordnet ist, der den Druck auf das Element einleitet, und daß sich der Sensor und ein Hybrid (21) mit seinem Träger (20) und den darauf angeordneten elektronischen Bauteilen (28) der Auswerteschaltung auf dem Gegenlager (22) des Stempels (18) befinden. 2. Pressure sensor according to claim 1, characterized in that between a membrane (14) and the sensor, a stamp (18) is arranged, which initiates the pressure on the element, and that the sensor and a hybrid (21) with its carrier (20) and the electronic components (28) of the evaluation circuit arranged thereon are located on the counter bearing (22) of the stamp (18).
2. Druckgeber nach Anspruch 1, dadurch gekennzeichnet, daß das Element (19) auf dem Träger (20) des Hybrids (21) angeordnet ist. 2. Pressure sensor according to claim 1, characterized in that the element (19) on the carrier (20) of the hybrid (21) is arranged.
3. Druckgeber nach Anspruch 1 und/oder 2, dadurch gekennzeichnet, daß der Hybrid (21 ) auf der dem Stempel zugewandten Seite des Gegenlagers (22) angeordnet ist. 3. Pressure sensor according to claim 1 and / or 2, characterized in that the hybrid (21) is arranged on the side of the counter-bearing (22) facing the stamp.
4. Druckgeber nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der Träger (20) des Hybrids (21) aus Al2O3 besteht. 4. Pressure sensor according to one of claims 1 to 3, characterized in that the carrier (20) of the hybrid (21) consists of Al 2 O 3 .
5. Druckgeber nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die elektronischen Bauteile (28) mit Hilfe von Bonddrähten (31) und Dickschichtleiterbahnen verbunden sind. 5. Pressure transmitter according to one of claims 1 to 4, characterized in that the electronic components (28) are connected by means of bonding wires (31) and thick-film conductor tracks.
6. Druckgeber nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß der Stempel (18) aus Glaskeramik besteht. 6. Pressure sensor according to one of claims 1 to 5, characterized in that the stamp (18) consists of glass ceramic.
7. Druckgeber nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß das Gegenlager (22) in das Gehäuse (10) eingepreßt ist. 7. Pressure sensor according to one of claims 1 to 6, characterized in that the counter bearing (22) in the housing (10) is pressed.
PCT/DE1991/000530 1990-07-18 1991-06-27 Pressure sensor for determination of the pressure in a combustion chamber of an internal-combustion engine WO1992001916A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1019920700307A KR920702493A (en) 1990-07-18 1991-06-27 Pressure sensor for detecting pressure in combustion chamber of internal combustion engine

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4022780A DE4022780A1 (en) 1990-07-18 1990-07-18 PRESSURE SENSOR FOR DETECTING PRINTERS IN THE COMBUSTION CHAMBER OF COMBUSTION ENGINES
DEP4022780.4 1990-07-18

Publications (1)

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WO1992001916A1 true WO1992001916A1 (en) 1992-02-06

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PCT/DE1991/000530 WO1992001916A1 (en) 1990-07-18 1991-06-27 Pressure sensor for determination of the pressure in a combustion chamber of an internal-combustion engine

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EP (1) EP0494279A1 (en)
JP (1) JPH05501311A (en)
KR (1) KR920702493A (en)
DE (1) DE4022780A1 (en)
WO (1) WO1992001916A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005315602A (en) * 2004-04-27 2005-11-10 Nippon Seiki Co Ltd Semiconductor sensor device

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0172943A1 (en) * 1984-08-24 1986-03-05 VDO Adolf Schindling AG Strain gauge
US4620438A (en) * 1983-12-15 1986-11-04 Texas Instruments Incorporated Cylinder pressure transmitter for an internal combustion engine
FR2626670A1 (en) * 1987-06-17 1989-08-04 Gazzano Maurice Pressure and deformation sensor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4620438A (en) * 1983-12-15 1986-11-04 Texas Instruments Incorporated Cylinder pressure transmitter for an internal combustion engine
EP0172943A1 (en) * 1984-08-24 1986-03-05 VDO Adolf Schindling AG Strain gauge
FR2626670A1 (en) * 1987-06-17 1989-08-04 Gazzano Maurice Pressure and deformation sensor

Also Published As

Publication number Publication date
KR920702493A (en) 1992-09-04
JPH05501311A (en) 1993-03-11
EP0494279A1 (en) 1992-07-15
DE4022780A1 (en) 1992-01-23

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