Robert Boschgmbh

Gerhard Holfelder

Klaus D Muller

Hermann Dietz

Friedrich J Esper

Harald Reber

Ernst Linder

Karl-Hermann Friese

Franz Rieger

Helmut Maurer

Werner Grunwald

Claudio De La Prieta

Heinz Geier

Kurt Schmid

Thomas Frey

Klaus D M/u/ Ller

Karl H Friese

Gunther Knoll

Hermann Ziener

A printing paste suitable for application by an elastically deformable stamp on a substrate and method for said application. The paste comprises a powdered solid component in an organic carrier with a weight ratio of between 6:4 and 8:2. The organic carrier comprises 4-9% by weight ethyl cellulose, 74-82% alpha-terpineol, and 8-17% benzyl alcohol. The paste may also contain up to 20% by weight of polyethylene glycol. The solid component of the paste is preferably a mixture of platinum and zirconium dioxide which can be applied as an electrically conductive paste to form a conductive coating on a substrate, preferably a tubular or other substrate having a non-planar surface. The paste has a viscosity of between 6 and 8.5 pascal seconds.

Printing paste and method of applying said paste

To provide access of gases to an electrode (39, 48) positioned on a flat plate (35) of solid electrolyte material, under controlled conditions, and while preventing access of gases to the electrodes where not desired, the electrodes are covered with a porous cover layer (42, 49) of sintered granular material, for example of zirconium dioxide, having a grain size of 10 .mu.m, and 25 .mu.m thick, with void or pore-formation material added thereto which, upon sintering, becomes volatile and leaves a porous structure. A gas-tight tunnel covering (44, 51) extends over the electrode and filler covering leaving an open space in those regions where the electrode is exposed to the desired gas, for example a test gas adjacent the sensing end (11/1) of the sensor, or oxygen from ambient air adjacent the connecting or terminal end (11/3) of the sensor, the respective gas to be applied to the electrode diffusing through the pores of the porous structure to the respective electrode.

Electrochemical oxygen sensor, particularly for analysis of combustion

To permit simultaneous evaluation of the light as a consequence of combustion in the combustion chamber of an internal combustion (IC) engine, and evaluation of the oxygen content of the combustion gas resulting from the combustion, a tubular housing of generally spark-plug shape is closed off at the end facing the combustion chamber by a solid electrolyte body in form of a disk (6), closed tube or thimble (6c) or the like, which is made of transparent zirconium dioxide. The interior of the housing has a light guide (7) extending therein. The solid electrolyte body has electrodes (11, 11'; 11c, 11'c) applied thereto, electrically connected to an electrical evaluation stage (EE) to determine oxygen concentration in the combustion gases, while the light due to combustion is transmitted through the solid electrolyte to the light guide for evaluation in an optical evaluation stage (EO). The ceramic body may be ground to form a lens to focus light resulting upon combustion on the light guide which can have a jacket (15) which is electrically conductive to provide one output terminal from the electrodes applied to the solid electrolyte body, the other electrode being connected through the housing to chassis.

Combination gas oxygen concentration and combustion light sensor

To decrease the preheat time and power requirements in preheater-type glow plugs for Diesel engines, a closed ceramic tube (20), for example of aluminum oxide and of about 5 mm diameter has, on the bottom (21) thereof applied a layer or film-like heater element (24, 24'), for example in an undulating or zig-zag configuration (FIG. 2) or in form of a constriction or pinch (FIG. 4: 24') to provide a concentrated point or strip source of heat. The heater layer itself is protected by a protective coating (25) and, to provide for the required heat distribution, the underlying bottom (21, 21') of the tube (20, 20') supports an insulating intermediate layer and possibly a heat conductive layer is intermediate. Preheat times in the order of 1-2 seconds, with lower current consumption than prior wound-wire plugs can be obtained.

Glow plug, particularly for diesel engine

To permit easy attachment, for example, by soldering, of a connecting lead wire to a conductive track on a ceramic plate connected closely adjacent to another plate which may also be ceramic, the first ceramic plate, at least, is bent away from the other ceramic plate at the connecting portion during manufacture; the manufacturing process includes heating the plate to be bent away to be in plastic condition and then applying a bending force to form the bend, permitting the so bent plate to cool, and joining the so-bent plate to the other plate with which it is to form a composite, for example, by glass melt. The bending force may be gravity, by permitting the unsintered plate, upon heating, to fall on a curved surface; or the bending force can be generated by applying a layer of a material having differential shrinkage to the flat, unsintered plate, and heating the composite, so that, upon differential shrinkage, the ceramic plate will be bent away from its originally plane, flat state.

Method to render accessible an electrical contact region of a composite

To permit a layer construction, which is inexpensive and lends itself to mass production manufacture, a solid electrolyte body, in plate-like construction, with electrodes at either thereof is positioned in a housing with a portion thereof extending in the region where it is exposed to gases to be sensed; a porous cover is applied on one of the electrodes, the porous cover having a predetermined diffusion resistance to oxygen molecules. A flat insulating plate of approximately the same dimension as the solid electrolyte plate is positioned flat thereagainst, and a flat layer-like electrical heating element is secured on the flat insulating plate or, in other embodiments, against another insulating covering on the other side of the heating element as well, close to the electrodes and adjacent the plane surfaces of the body. The heating element and the electrodes of the sensing element are carried out as conductive tracks for connection to respective sources of operating or biassing potential and, with respect to the sensing electrodes, to an evaluation circuit.

Electrochemical oxygen sensor, particularly for use with exhaust gases

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Ditzingen, Germany

Gerhard Holfelder