Abstract: The method reduces the nitrogen oxide concentration in the exhaust of an internal combustion engine. A noticeable reduction in the NO.sub.x emission of a diesel motor can be achieved by applying the Selective Catalytic Reduction (SCR) method. In this method, ammonia is injected into a catalyzer through which the exhaust gas flows, this ammonia reacting with nitrogen monoxide or, respectively, nitrogen dioxide to form nitrogen and water. Since the exhaust gas should contain neither nitrogen monoxide nor excess ammonia, suitable methods are required for regulating the metering of NH.sub.3. For controlling the amount of urea added to the exhaust gas as a reduction agent, the NO and NH.sub.3 concentration is measured using a detector located in the exhaust systems following the SCR catalyzer. The detector contains a vanadate layer manufactured on the basis of a specific sputtering method as a sensitive element.

Abstract: A sensor assembly for sensing gaseous or fluid medium such as sensing oxygen within exhaust gas of an automobile. The assembly provides a sensor element within a housing mounted within a S-shaped flow channel between a medium entry aperture and exit aperture. A shield is provided upstream of the sensor in a flow direction of the medium. The arrangements provide for a laminar flow across the sensor element causing reduced deposits on the surface of the sensing element for a more accurate sensor and a longer service life of the sensor element.

Abstract: A rapid temperature sensor formed of a metal from the platinum group is provided. The rapid temperature sensor includes a substrate over which a platinum resistive layer is provided. A double layer, forming a passivation layer, is provided over the platinum resistive layer to prevent oxidation. The double layer includes a ceramic layer and a glass layer. The double layer prevents oxygen from reaching the platinum resistive layer even at temperatures up to 1,000.degree. C.

Abstract: A housing for a fast exhaust gas sensor for cylinder-selective lambda measurements in an internal combustion engine comprises a hollow-cylindrical housing having at least two slot shaped openings that are arranged rotationally symmetrical over the circumference of the wall of the housing and extend parallel to the axis of the housing. Each of the slot shaped openings have edges that are overlapping in the fashion of a venetian blind so that the rotational symmetrical arrangement of the openings allows the housing and the exhaust gas sensor mounted within the housing to be integrated in an arbitrary rotational attitude relative to the exhaust gas stream in a pipe of a system.

Abstract: Integrated design of a combustion pressure sensor (11, 12, 13, 14) and combustion heat-flow sensor (21) which is suitable for determining a physical variable of the combustion process of an engine.

Abstract: A fuel injection nozzle for a combustion engine not only has a valve for alternately opening and closing the nozzle, but also has a part which undergoes alternating stroke movement, either longitudinally or transversely. The alternating stroke movement changes the opening angle of the nozzle opening. The alternating stroke movement is in a frequency range of approximately 5 to 20 kiloHertz.

Abstract: Laser-induced color printing with means with which the printing color of a micro-capsule to be impinged by the laser beam (12) is identified. These means are a fluorescence transformer material as a constituent of the content of the micro-capsules (3) or an additional white light ray with which the printing color of an individual micro-capsule (3) can likewise be identified.The printing ensues given coincidence of a printing instruction provided for a defined location with color specification and of the momentary incidence of the scanning laser beam (12) on a micro-capsule (3) for which this printing color has been identified as being present.

Abstract: With the present tank ventilation system formed of a fuel tank, an active carbon filter, a control unit, a lambda probe, a tank ventilation valve and a flow sensor it is possible to recognize defects at the connecting lines and the ventilation valve immediately. For the recognition of the defect, a control unit is provided which examines the signals arriving from the lambda probe and from the flow sensor along with the outgoing tank ventilation control signals for unreasonable events. When a defect is recognized, the error signal is stored. A ceramic PTC resistor is preferably employed as the flow sensor.

Abstract: A pyrodetector, which is both movement selective and directional selective, has preferably a foil supporting detector elements relative to a concave mirror which may have a spherical curve surface, a spherical-parabolic curve surface or a curve surface between a spherical surface and a spherical-parabolic surface. The sensor is preferably a plurality of individual sensor elements which are arranged on an arc, preferably on a planar member or a foil, and may include additional or second sensor elements having electrodes which are for determining temperature compensation for the detector.

Abstract: A sensor element arrangement for a pyrodetector has a concave mirror with a sensor element arranged at a focus of the concave mirror and further sensor elements arranged laterally therefrom. Electrodes of both polarities are present on each side of the film, these electrodes being respectively separated from one another by quasi-meander-like, metal-free strips which engage into one another in the form of hook portions. The electrodes on the upper side reside opposite corresponding electrodes on the lower side for the formation of the sensor elements, and these electrodes are connected to one another at edge regions by connection lines. The sensor element arrangement together with the film and the connection lines is surrounded by a retaining frame which is insertable into the mounting of the concave mirror in centered and adjusted fashion.

Abstract: A sensor element arrangement for a pyrodetector has a concave mirror with a sensor element arranged at a focus of the concave mirror and further sensor elements arranged laterally therefrom. Electrodes of both polarities are present on each side of the film, these electrodes being respectively separated from one another by quasi-meander-like, metal-free strips which engage into one another in the form of hook portions. The electrodes on the upper side reside opposite corresponding electrodes on the lower side of the formation of the sensor elements, and these electrodes are connected to one another at edge regions by connection lines. The sensor element arrangement together with the film and the connection lines is surrounded by a retaining frame which is insertable into the mounting of the concave mirror in centered and adjusted fashion.

Abstract: A pyrodetector having a concave mirror containing a sensor element arranged in a focus thereof. The sensor element is on a film and is distinguished by a compact structure. The concave mirror is formed of a body having a rectangular cross-section, of a reflector part, and of sidewalls positioned perpendicularly relative to one another. An opening is provided in a reflector portion through which a retaining part provided with plug pins is inserted. The concave mirror, an evaluation means arranged outside of the concave mirror behind the reflector portion, and a honeycomb lattice and a covering are accommodated as an overall arrangement in a housing.

Abstract: An electrically actuated positioning element system utilizes a positioning element formed of piezo-electrical bodies each formed of a plurality of lamellae having electrodes. The lamellae have a length substantially greater than their thickness and upon application of an electrical voltage with a field direction which promotes a polarization of the material of the lamellae, the body is shortened. The two bodies are connected to one another at one end by a cross arm and at the other end the one body end is active and free to move relative to the other body end such that a resultant relative motion occurring between the two body ends may be utilized. Preferably a connection is provided for absorbing a lateral thrust of the bodies. The two piezo-electrical bodies are each electrically connected to one another for reverse-phase operation such that one contracts while the other is in a lengthened condition and vice versa.

Abstract: A heating device for preheating heating oil flowing through a pipe has a heat conduction body to which a plate-shaped ceramic PTC resistance heating element is connected in heat exchange-relationship. The heating element has a thickness in the range of 0.5 to 2 millimeters, a Curie temperature between 120.degree. and 220.degree. C. and a specific resistance of 430 to 5000 ohm-cm rated at a supply voltage between 110 and 220 volts such that the maximum temperature achieved by the heating element over a range of heat transfer rates is relatively constant and is determined by the resistivity and the Curie temperature of the heating element rather than by the rate of heat transfer. If designed for energization at 220 volts, the heating element has the same thickness and Curie temperature as in the first example described above, but with a specific resistance of 1700 to 20,000 ohm-cm as measured at 220 volts.

Abstract: A heating device has a PTC resistor plate as the heating element and is covered with an insulating body. Between the heating element and the insulating body, on each of opposite surfaces of the heating element, ductile metal layers, preferably aluminum, are provided under a permanent pressure of at least 0.3.times.10.sup.8 Pa, the layers being designed as current supply electrodes having electrical terminals. The resistor plate may advantageously have a surface roughness in the magnitude of 100 .mu.m.

Abstract: A system is disclosed for indicating when a flow heater used for vaporization of water and heated by PTC resistors as heating elements therein must be decalcified. Within the flow heater a PTC resistor element is located at a water entry and also at a water exit region. A main PTC heater element is also provided between the entry and exit elements. Separate power supply lines are run to the exit and entry heating elements and an electronic circuit is provided which determines when a difference in current flow in the exit heating element compared to the entry heating element exceeds a given value indicative of the need for decalcification. The circuit connects with an indicator which is triggered when decalcification is required.

Abstract: An immersion heater is disclosed having a heating member with a small thickness and comprised of PTC thermistor material. The heating member has the same heat contact between each of its two major surfaces and the medium to be heated. A Curie temperature T.sub.C and a specific resistance .rho..sub.T.sbsb.C of the material are dimensioned such that with a given operating voltage U a temperature regulation for the range with the positive temperature coefficient of the material results. By use of the upper limit of the Curie temperature T.sub.C, extensive protection against fire can be obtained in the case of inappropriate handling of the immersion heater.

Abstract: A heater is disclosed having a PTC thermistor heating element rigidly wedged in an intermediate space of the member to be heated by use of at least one wedge-shaped member. The wedge-shaped member has a surface which is at least the size of the heating elment so an optimum heat transmission is guaranteed.

Abstract: A heating device is disclosed having a disc-shaped heating element consisting of PTC thermistor material typically operated by a network voltage of 220 volts. The PTC thermistor material has a cut-off control property at a desired cut-off temperature so as to minimize further heat rises of the heating element above the cut-off temperature. In this fashion, the possibility of fire damage is reduced. The heating element has a specific heat output of greater than 50 watts per cm.sup.2 and the PTC thermistor material is selected to have a Curie temperature which is at least 50.degree. K. higher than the cut-off temperature. A heating body is provided to affect a substantially even dissipation of heat from two sides of the heating element.