Robert Boschgmbh

Gunther Stecher

Klaus D Muller

Karl-Hermann Friese

Herbert Zimmermann

Kurt Spitzenberger

Ernst Linder

Helmut Maurer

Hans-Martin Wiedenmann

Hans Hecht

Botho Ziegenbein

Wolfgang Leibfried

Franz Rieger

Hermann Dietz

Dietrich Bergfried

Richard Muehlheim

Ulrich Kippelt

Klaus Steinle

Heinz Walter

Hans J Glas

Alfred Grob

Karl Rampmaier

A sensor (10) for measurement of acceleration and/or tilt of a movable object, particularly a motor vehicle, features an interior space (12) partially filled with fluid (15). Within that space, at least two heatable, temperature-sensitive electrical circuit elements are arranged so that, in a rest or initial position of the sensor, they are equally covered or wetted by the fluid. If the acceleration and tilt of the movable object are both zero, or the two cancel each other out, the sensor reading is zero. If this is not the case, the acceleration or tilt leads to a differing degree of coverage or wetting of the at least two circuit elements, and thus to a non-zero sensor reading.

Fluid-based acceleration and tilt sensor

Device for measuring a flowing air quantity

A PTC temperature sensor and a process for producing PTC temperature sensing elements from ceramic films for a PTC temperature sensor are proposed. The PTC temperature sensing elements are so designed that the PTC resistor track is hermetically encapsulated with respect to the gas being measured and the ambient air. Ceramic films based on an insulator ceramic, in particular based on Al.sub.2 O.sub.3, and ceramic films based on a solid electrolyte can be used to produce the temperature sensing elements. The PTC temperature sensor according to the invention is distinguished, in particular, by the fact that, while the manufacturing procedure is cheap, it is not subject to aging due to the effect of varying O.sub.2 partial pressures, has a high resistance to aging of the resistance characteristic in rich and lean gas mixtures, for example in motor vehicle exhaust gases, at 300.degree.-1000.degree. C. and has a construction free from extraneous potential, is characterized by short response times owning to its low heat capacity and is suitable for incorportion in very narrow housing as a consequence of small dimensions.

Process for producing PTC temperature sensor elements for PTC

NTC temperature sensor and process for producing NTC temperature sensing

A free-standing, self-supporting layer of glass-ceramic or crystallized glass is applied by thick-film technology over a presintered layer made of a vaporizable or etchable material which, after sintering the thick-flim glass-ceramic or crystallized glass layer (3) to a substrate (1), is removed by heating or etching. The layer (2) to be removed is preferably applied in paste form with the glass-ceramic thick-film layer (3) thereover either in form of a crossing bridge, as a partially covering cantilever, or entirely surrounding the layer 2, in which latter case the thick-film layer (3) is of porous construction so that the volatile or vaporizable components of the underlying layer (2) can escape through the thick-film layer (3). A typical layer which is volatile or vaporizable includes carbon black, a resin binder and a solvent, applied to a substrate, for example of ceramic or enameled metal, over which the glass-ceramic layer is applied. Electrically conductive tracks can be applied directly on the substrate beneath the layer (2) to be removed, and to the thick-film layer, or in the form of strain or temperature-sensitive resistors, for connection to an external circuit evaluating deformation of the free-standing layer by capacitative or resistance change, to obtain pressure sensors, vibration sensors, acceleration sensors, and the like of minute construction. A typical dimension of the thick-film layer is in the order of tens of micrometers, with the free space after removal of the filler (2) being also about in the order of tens of micrometers.

Method of making an electrical thick-film, free-standing,

High pressure sensor

A pressure measuring element includes a plate-shaped substrate of ceramic material and a membrane deformable in response to pressure fluctuations. The membrane is made of ceramic material and is mounted to the upper side of the substrate. A pressure-sensitive resistor for measuring pressure is positioned inside the membrane. A heating resistor element is positioned on the underside of the substrate, which maintains the temperature of the substrate constant. A temperature sensor is also arrayed on the upper side of the substrate near the membrane.

Pressure measuring element

A free-standing, self-supporting layer of glass-ceramic or crystallized glass is applied by thick-film technology over a presintered layer made of a vaporizable or etchable material which, after sintering the thick-film glass-ceramic or crystallized glass layer (3) to a substrate (1), is removed by heating or etching. The layer (2) to be removed is preferably applied in past form with the glass-ceramic thick-film layer (3) thereover either in form of a crossing bridge, as a partially covering cantilever, or entirely surrounding the layer 2, in which latter case the thick-vaporizable film layer (3) is of porous construction so that the volatile or components of the underlying layer (2) can escape through the thick-film layer (3). A typical layer which is volatile or vaporizable includes carbon black, a resin binder and a solvent, applied to a substrate, for example of ceramic or enameled metal, over which the glass-ceramic layer is applied. Electrically conductive tracks can be applied directly on the substrate beneath the layer (2) to be removed, and to the thick-film layer, or in the form of strain or temperature-sensitive resistors, for connection to an external circuit evaluating deformation of the free-standing layer by capacitative or resistance change, to obtain pressure sensors, vibration sensors, acceleration sensors, and the like, of minute construction. A typical dimension of the thick-film layer is in the order of tens of micrometers, with the free space after removal of the filler (2) being also about in the order of tens of micrometers.

Electrical thick-film, free-standing, self-supporting structure, and

A deformable membrane is made by applying, by thick-film technology, a glass-ceramic paste over a vaporizable or burnable filler material, containing primarily carbon black in a binder which, in turn, is located on a substrate, for example of ceramic, glass, enameled metal or the like. The substrate for example is about 1.5 cm square, the membrane glass ceramic being applied as a circular dot of about 0.5 cm diameter. After solidifying the paste forming the membrane in a protective gas atmosphere, for example at about 950.degree. C., the filler is burned out in an oxidizing atmosphere, to escape through pores in the membrane material. By selecting a membrane material which has a lower thermal coefficient of expansion than that of the substrate, after burning, the membrane will assume a convex shape leaving a hollow space (8) beneath it and the substrate. The membrane is pressure-sensitive, for example when a predetermined quantity of a predetermined gas under a predetermined pressure is sealed therein, or if access to the interior of the space is provided through the substrate, for example by a tiny duct which is connected to a flange or stub connection. Electrical output can be obtained by applying either a metallic layer cover the membrane and utilizing the capacity of the metallic layer with respect to a counter electrode, or applying strain-compression sensitive resistors on the membrane. The membrane, after the electrodes or resistors are applied, is coated with a protective glass glaze (6). The pressure transducer is particularly for determining the pressure conditions in the induction pipe of an internal combustion engine.

Pressure sensor

To apply a measured quantity of air to the electrodes applied to a plate-like solid electrolyte body, which may be a chip on a carrier or may, itself, form the carrier, grooves, flutes, ducts, or depressions are formed in the carrier and/or a cover plate, the grooves terminating at an edge portion with access to the gas to be supplied, and having a size such that their clear height is preferably in the lower micron region, and a width, preferably under 1 mm, and particularly between 0.2 and 0.4 mm. The higher limits are applicable to apply, for example, air to a reference electrode, to apply ambient oxygen thereto; the lower limits are appropriate when operating the sensor as a polarographic sensor, in which the diffusion limited current, upon application of a bias voltage, is an analog measure of the oxygen concentration in the gas, and the gas supply to the electrode must be suitably controlled to prevent saturation conditions. The grooves may be formed, for example, by sandblasting or by applying insulating material in the form of posts, ridges, and the like, on the respective element, filling the space therebetween with a filler substance which, upon subsequent sintering, escapes, thus leaving the voids forming the grooves, depressions, and the like.

Flat electrochemical sensor, and method of its manufacture

To simplify manufacture and provide a polarographic sensor of high response speed, operating according to the current limiting principle, an oxygen molecule migration barrier is provided leading to the cathode by separating the cathode from the space where the gas to be tested exists by a wall through which a hole is provided which extends therethrough to a small space immediately above the cathode defined by support elements placed immediately on the cathode. The hole, or a plurality of holes, is so dimensioned that the diameter thereof, with respect to its length, is small, with diameters of between 0.01 to 0.06 mm and a length of at least about 1 mm being suitable.

Oxygen sensor of the polarographic type, particularly for use with

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Ludwigsburg, Germany

Gunther Stecher