Robert Bosch

Harald Reber

Klaus D Muller

Hermann Dietz

Ernst Linder

Franz Rieger

Helmut Maurer

Gerhard Holfelder

Ferdinand Grob

Friedrich J Esper

Karl H Friese

Hermann Ziener

To permit calibrating and testing a current-limiting sensor in situ, the sensor is exposed, from time to time, to ambient air forming a standard gas, and the output thereof compared with a standard, for example by connecting a resistor (4) of standard value in circuit therewith or for recalling from a memory (23) in a microcomputer (22) standard conditions; upon determination of a deviation between output from the sensor (2) when exposed to the standard gas--typically air--and the theoretical value as stored, the theoretical or reference value is reset if the deviation is within a predetermined limit or, otherwise, an alarm output is provided. The tolerance limits can be set in such a way that a first alarm output is provided in a narrow tolerance, thus indicating drift of the sensor toward eventual malfunction, and permitting utilization of the sensor for long lifetime, while providing advance warning of imminent failure. Change of applied voltage to the sensor and test for current therethrough can then derive an actual operating curve which can be compared with stored test curves in the memory from which, upon extrapolation, a tendency to failure can be predicted and recognized.

Method for monitoring operation of a current-limiting type gas sensor

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

A method and apparatus is proposed for obtaining a control variable for the closed-loop control of the fuel-air ratio of the operating mixture of internal combustion engines, in which a threshold-current sensor of known structure is used. By means of varying the measurement voltage present at the threshold-current sensor by voltage amounts which correspond to a change in oxygen concentration to be expected in association with a change in operational state, the time behavior of the threshold-current sensor, which is essentially sluggish, is compensated for and it becomes possible to use it for rapidly-functioning closed-loop control systems in internal combustion engines.

Method and apparatus for obtaining a control variable for the

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

A storage battery containing a recombination catalyst wherein the recombined water vapor is conducted by a conduit into the electrolyte and is condensed therein. The storage battery contains battery plates in the liquid electrolyte. It contains a recombination catalyst and an upper enclosure and means for directing evolved oxygen and hydrogen gases to said recombination catalyst.

Storage battery with recombination catalyst

A closure plug containing a recombination catalyst is adapted to fit into an opening of a battery. It contains means for directing evolved oxygen and hydrogen gases to the recombination catalyst and also contains gas communication means to conduct the recombined water vapor below the surface of the electrolyte where it is condensed. The method is directed to operating a battery wherein gaseous oxygen and hydrogen are recombined to form water vapor in the upper portion of the battery and the recombined water vapor is then conducted through a conduit extending into the electrolyte wherein it is condensed.

Growing community of inventors

Gerlingen, Germany

Harald Reber