Abstract: The invention relates to a method for generating an ion current which occurs as a direct current between a central electrode and one or more side electrodes of a spark plug of a spark ignition engine which is supplied repeatedly with an ignition voltage from an ignition voltage source, wherein the spark ignition engine is assigned an engine control unit, which, in an engine cycle, determines for each spark plug a target ignition point and/or an activation point for the ignition voltage source before the target ignition point, and a second voltage source is provided, which delivers a second voltage for the generation of the ion current, wherein the second voltage source lying in the engine cycle for a first time interval ?t1, which is shorter than the duration of the engine cycle, is connected to the electrodes of the spark plug, and wherein the ion current flowing as a result of the application of the second voltage to the electrodes of the spark plug takes a path which avoids the ignition voltage source.

Abstract: The invention relates to a method for generating an ion current which occurs as a direct current between a central electrode and one or more side electrodes of a spark plug of a spark ignition engine which is supplied repeatedly with an ignition voltage from an ignition voltage source, wherein the spark ignition engine is assigned an engine control unit, which, in an engine cycle, determines for each spark plug a target ignition point and/or an activation point for the ignition voltage source before the target ignition point, and a second voltage source is provided, which delivers a second voltage for the generation of the ion current, wherein the second voltage source lying in the engine cycle for a first time interval ?t1, which is shorter than the duration of the engine cycle, is connected to the electrodes of the spark plug, and wherein the ion current flowing as a result of the application of the second voltage to the electrodes of the spark plug takes a path which avoids the ignition voltage source.

Abstract: A measuring arrangement is provided with a soot filter for use in flowing, soot particle-bearing gases, as well as a method for monitoring the operability of a soot filter arranged in an exhaust gas conduit, wherein at least one component stream of an exhaust gas stream flows through at least one molded element which is open-pored at least in the flow direction, and wherein the temperature of the molded element is measured with at least one temperature probe. In the measuring arrangement the soot filter is allocated at least one soot sensor, which has at least one molded element which is openpored at least in the flow direction, at least one electric heating element, and at least one temperature probe. The measuring arrangement and method make possible a monitoring of the operability of a soot filter in a reliable and direct manner.

Abstract: A gas sensor is provided for measurement of oxygen and/or the air-to-fuel lambda ratio and hydrocarbons and/or carbon monoxide in gas mixtures. To reliably measure a plurality of gaseous components, the sensor is provided with a reference electrode representing a constant oxygen partial pressure, an oxygen ion-conducting solid electrolyte, and at least two measuring electrodes, the measuring electrodes and the reference electrode being mounted directly on the solid electrolyte and having electrical leads for connection and for take-away of electrical measurement signals. The solid electrolyte (1) is constructed with a measurement gas side exposed to the gas mixture and a reference gas side separated from the gas mixture.

Abstract: A method of measuring oxygen and/or the air-to-fuel lambda ratio and hydrocarbons and/or carbon monoxide in gas mixtures using a gas sensor is provided. To reliably measure a plurality of gaseous components, the sensor is provided with a reference electrode representing a constant oxygen partial pressure, an oxygen ion-conducting solid electrolyte, and at least two measuring electrodes, the measuring electrodes and the reference electrode being mounted directly on the solid electrolyte and having electrical leads for connection and for take-away of electrical measurement signals. The solid electrolyte is constructed with a measurement gas side exposed to the gas mixture and a reference gas side separated from the gas mixture.

Abstract: A sensor and method are provided for ascertaining a soot concentration in flowing, soot particle-bearing gases, wherein at least a component stream of a soot particle-bearing gas stream flows through at least one molded element which is open-pored at least in the flow direction, and wherein the temperature of the molded element is measured with at least one temperature probe. The sensor is a soot sensor, which has at least one molded element which is open-pored at least in the flow direction, at least one electric heating element and at least one temperature probe.

Abstract: A measuring arrangement is provided for soot particle-bearing gases, having a soot sensor in a gas conduit, and its use in methods for determining a soot concentration in flowing, soot particle-bearing gases, wherein at least one component stream of a soot particle-bearing gas stream in a gas conduit flows by and/or through at least one electrically-conducting structure. The problem presents itself of making available a sensor and a method for determining soot concentrations in flowing gases, with which even small amounts of soot can be reliably recorded. The problem is solved by a measuring arrangement with a soot sensor, which has an electrically-conducting structure with an electrical charge, and wherein an arrangement for generating another electrical charge on the soot particles is provided in the gas upstream of the soot sensor.

Abstract: A measuring arrangement is provided with a soot filter for use in flowing, soot particle-bearing gases, as well as a method for monitoring the operability of a soot filter arranged in an exhaust gas conduit, wherein at least one component stream of an exhaust gas stream flows through at least one molded element which is open-pored at least in the flow direction, and wherein the temperature of the molded element is measured with at least one temperature probe. In the measuring arrangement the soot filter is allocated at least one soot sensor, which has at least one molded element which is open-pored at least in the flow direction, at least one electric heating element, and at least one temperature probe. The measuring arrangement and method make possible a monitoring of the operability of a soot filter in a reliable and direct manner.

Abstract: Oxygen sensor for measuring resistance as a function of oxygen partial pressure, made of alkaline-earth-doped perovskitic lanthanum ferrites with the general formulaLa.sub.1-x Me.sub.x FeO.sub.3-.delta.where Me is one of alkaline earth metals, Mg, Ca, Sr, and Ba, x is a degree of doping of the lanthanum ferrites. The oxygen sensor oxygen deficit of anion is 6=0 to 0.25, and the degree of doping of the lanthanum ferrites is x=0.1 to 0.3 and is selected to provide a temperature independent resistance property to the oxygen sensor in a lean range.

Abstract: The invention relates to a catalytic layer system on a resistive gas sensor, especially on a resistive gas sensor layer on a titanate base, with at least one first layer and a second layer lying over the first layer, where, according to the invention, the first layer exhibits a catalytically active substance whose volume percentage in the layer ranges from 20 to 80%. In addition, the first layer contains a titanate that corresponds to at least one titanate of the underlying gas sensor layer. This attribute guarantees favorable adhesion between the layers. Furthermore, an oxide mixture that contributes to the improved mechanical stability of the layer system is provided in the second layer instead of the catalytically active substance. To manufacture the catalytic layer system, the individual layers are applied to the sensor in a screen printing process, which allows for a rational method of production and the precise dosing and distribution of the individual layer components.

Abstract: The invention relates to a protective coating on at least one electrical conductor and/or semiconductor, especially an electric sensor, in which a porous first protective coating is applied directly to the surface of the electrical conductor and/or semiconductor and a gas-tight second protective coating is applied at least to regions of the first protective coating.

Abstract: An oxygen sensor made of alkaline-earth-doped perovskitic lanthanum ferrites with the general formula:La.sub.1-x Me.sub.x FeO.sub.3-.delta.where Me is one of the alkaline earth metals, Mg, Ca, Sr, and Ba and x is the degree of doping, and the oxygen deficit of anion .delta.=0 to 0.25. The degree of doping of the lanthanum ferrites is x=0.1 to 0.3 and resistance is measured in the lanthanum ferrites as a function of oxygen partial pressure.

Abstract: Cuprate mixed oxides having the general formula Ln.sub.2 CuO.sub.4+y, in which Ln stands for at least lanthanum or a trivalent element from the group of rare earths with atomic numbers from 58 to 71, and the O.sub.2 stoichiometric deviation y lies in the 0.001 to 0.1 range, are particularly suitable for use in oxygen sensors, for example in exhaust gas systems.

Abstract: An electrically conductive connection is made between a metal connector and a metal layer applied and bonded by sintering to a ceramic substrate comprising glass and/or vitreous ceramic in small quantities. An adhesion-promoting layer having a glass and/or vitreous ceramic and metal particles is applied and bonded by fusion to the ceramic substrate. The metal layer with the sintered bond is then applied to the ceramic substrate and the connector is welded to the metal layer by laser welding.

Abstract: The invention relates to a combination of a heated lambda sensor with a stepped or binary sensor characteristic and another heated lambda sensor to determine the lambda value in a gas mixture, e.g. in the exhaust gas preferably of internal combustion engines, the output signal from one lambda sensor being used to calibrate the other one, and the two lambda sensors are arranged closely beside each other, the other lambda sensor having a wide-baud sensor characteristic.

Abstract: The invention concerns a device for continuously monitoring the level of at least one gaseous constituent in a mixture of gases. The drawbacks of the known devices are complexity, high power consumption, large size, and, due to their high mass, non-uniform distribution of temperature, entailing imprecise measurement, and inertia, especially at the commencement of operation. These drawbacks are eliminated with a base in the form of a water with at least two electrodes in the form of separated thin coatings and with a temperature sensor separated from the electrodes on one side and with a heater in the form of an electric-resistance heating coating on the other side.

Abstract: The invention concerns a process for manufacturing inert, catalytic or gas-sensitve ceramic layers for gas sensors which comprises coating an uncoated insulative substrate with a layer of paste composed of a powdered semiconductor material of SrTiO.sub.3 and an organic paste material having a thickness of 1 to 100 um and then subjecting the coated substrate to a three phase thermal treatment.

Abstract: Semiconductors for resistive gas sensors or resistive semiconductor gas sensors with high speed of reaction are disclosed. These semiconductors are appropriate to measure the partial pressure of oxygen and reducing gases in any predetermined measurement range between 10.sup.-30 and about 1 bar or in the whole of this measurement range, their resistance changes being caused by a volume effect. In particular, these semiconductors have a layer less than 100 .mu.m thick, predetermined geometric structure and clearly marked marginal zones. A specially doped semiconductor composed of perowskit having the general formula A'.sub.x A.sub.1-x-Z1 B'.sub.y B.sub.1-y-Z2 O.sub.3 is applied on a substrate with a paste of an organic base material by a thick film technique. By adding or removing at least one element or by using two different semiconductors the characteristic curve is clearly traced.