Avl List Gmbh

Piezocryst Advanced Sensorics Gmbh

Christian Reiter

Peter W Krempl

Wolfgang Schindler

Josef Glaser

Alexander Schricker

Herbert Thanner

Gernot Leuprecht

Martin Baumgartner

Dietmar Kroeger

Wolfgang Singer

Friedrich Radke

Friedrich Anton Holzinger

To render possible a high-quality, yet cost-effective provision suitable for mass production of a piezoelectric pressure transducer () with at least one piezoelectric measuring element (&#x2033;) arranged on a housing base part (), which measuring element is connected on the opposite side to a diaphragm (), the measuring element (&#x2033;) is fixed on an electrode sheet (&#x2033;') or directly on the base partor the diaphragm, wherein the electrode sheet (&#x2033;&#x2032;) wraps conductively and positively as well as in a manner fixing the layers around a contact pin () insulated with respect to the base part () and projecting outwards.

Piezoelectric pressure transducer

A sensor element () has at least one measurement element () with piezoelectric and pyroelectric properties, and measurement electrodes (). A measurement variable and a disturbance variable act simultaneously upon the at least one measurement element () and the measurement signal derived from the measurement electrodes () includes an interference signal. The sensor element () has at least one compensation element (') upon which only the disturbance variable acts, so that a correction signal used to compensate for the interference signal in the measurement signal can be derived from the compensation element (). The invention consists in that the compensation element (&#x2032;) is in thermal contact with a first support () and with a second support () of the measurement element (), or with the measurement element (), over its length between the supports (), so that substantially the same temperature field is established in the measurement element () and in the compensation element (&#x2032;).

Sensor element having at least one measurement element with piezoelectric and pyroelectric properties

The invention relates to a method for determining the non-volatile component of aerosol particles in a gas sample, especially in the exhaust gas of internal combustion engines, where the aerosol particles are deposited on an oscillating sensor () of at least one crystal microbalance (), and the change in at least one oscillation parameter of the oscillating sensor is employed as measurement variable. According to the invention the oscillating sensor () of at least one crystal microbalance () is maintained at a temperature of more than 200&#xb0; C. during deposition of the aerosol particles, and preferably between 250&#xb0; C. and 350&#xb0; C.

Method and apparatus for determining the non-volatile component of aerosol particles in a gas sample

A process to determine aerosol particles in gaseous samples, specifically in the exhaust of diesel motors, includes the at least indirect deposit of aerosol particles on a piezoelectric oscillating crystal and the determination of the oscillation parameters of the piezoelectrically stimulated oscillation of the crystal. In order to assure the required reproducibility reliably and independently of the type of aerosol particles, and thus to achieve a high quality of measurements, the piezoelectric crystal is charged to oscillation during less than half the period of deposit of aerosol particles.

Method for the measurement of aerosol particles in gaseous samples

An arrangement is described for the quantitative and qualitative analysis of particles in gases, especially of particles in the exhaust gas of internal combustion engines, comprising a vibrating system with at least one vibration sensor, preferably a piezoelectric resonator, which is provided with at least one collecting surface for the particles to be analyzed, a circuit for the determination of characteristic vibration parameters as well as guide and transport arrangements for the gas to be analyzed. In order to obtain as large as possible a measuring range with a linear characteristic line and therewith a great sensitivity and dynamics with respect to the mass load in the entire measuring range, there is provided a vibration sensor stationary relative to the measuring chamber, and at least one active deflecting device for the gas or the particles contained in the gas.

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Graz, Austria

Christian Reiter