DE2738882A1 - Oxygen concentration measurement sensor - has solid electrolyte, internal reference electrode and external signal forming electrode with inorganic porous layer - Google Patents

Abstract

The sensor has solid electrolyte in the form of a cylinder with a closed end made of a material permeable for oxygen ions, a reference electrode on the solid electrolyte inner surface, and a further electrode on the gas measurement surface of the electrolyte. It delivers an output signal. The electrode on the electrolyte (2a) gas measurement surface includes an output signal generating electrode (2b) produced by plating at least the closed end of the electrolyte. There is also an electrode (2c) collecting the output voltage, produced by a metal paste on a suitable point of the electrolyte (2a) outer surface and connected to the electrode (2b). There is further an electrode reinforcing device (2d), at least on the outer side of the electrode (2b). An inorganic porous layer (2c) is produced on the outer surface of the electrode reinforcement (2d).

Description

Description The present invention relates to an oxygen sensor according to the preamble of claim 1 and to a method for its rapid deployment according to the preamble of claim 11.

Such oxygen sensors are used for systems that the three harmful components in automotive emissions by reaction with a catalytic converter can eliminate the unburned hydrocarbons at the same time (hereinafter referred to as "unburned HC"), carbon monoxide (CO) and nitrogen oxides (NOx). These systems are referred to below as a three-way system.

Air pollution is no longer a new problem. Have investigations Advances in the ecological effects of unburned HC, CO and NOx and the harmfulness of these components of automotive emissions was raised.

Various measures have been developed to render them harmless and tries how detoxification or cleaning systems with an oxidizing catalyst, a reducing catalyst or a combination of these two, and the three-way system, that the unburned HC, CO and NOx through reaction with a special catalyst can eliminate at the same time under special conditions. In particular the three-way system is an excellent detoxification system that has a high cleaning ability in the Shows range of theoretical air / fuel ratios; however, it makes the application this three-way system requires an oxygen sensor in the exhaust system is provided so that the oxygen concentration in the exhaust gas is measured or determined and can be fed back to control the fuel injection volume.

The oxygen sensor, in which an oxygen concentration cell from a solid electrolyte of one having an oxygen ion conductivity Special ceramic material is made, is used to reduce the oxygen concentration to be determined in a gas to be measured that the electromotive force is measured, which is due to the difference between the oxygen partial pressure of the gas to be measured and the reference gas, for example in the atmosphere. In a conventional oxygen sensor, platinum or other metals will turn on both sides of the solid electrolyte applied by different methods, for example by chemical plating, vapor deposition in vacuum, metallizing or by metal pasting followed by a heat treatment, thereby forming the metal electrodes are formed.

However, the electrodes thus formed have the following Disadvantage. In the case of a chemically plated electrode are the electrical ones Efficiency, such as the amount of electromotive force generated, the great or steep span change close to the theoretical air / fuel ratio, which Load characteristics and the internal resistance of the sensor are good, but occur because of the poor connectivity of the solid electrolyte with the metal and a large difference in the coefficient of thermal expansion in the hot exhaust gas Difficulties such as loosening the electrode from the solid electrolyte, Burning out, tearing off the trainline or physical and chemical fidelity. In the case of an electrode deposited by vapor or metallized, the scorching can occur or cracking of the electrode can be effectively prevented, however, they are different Above mentioned electrical capabilities are low. In addition, there is an electrode the end pasted and sintered platinum, although the binding capacity of the Electrode with the solid electrolyte well and there may be trouble like that Loosening, burning and cracking of the electrode can be effectively prevented, however the various electrical capacities are very low. For example is the area between the metal particles or the metal that makes up the electrode is made, and the solid electrolyte with a glassy substance (flux or flux) contained in the metal paste and that troubles causes, such as an increase in the internal resistance of the sensor, a deterioration in the load characteristic and a decrease in the size of the Output voltage change with the oxygen concentration in the gas to be measured.

Therefore, in a conventional oxygen sensor, in which a steep change in electromotive force around the theoretical air / fuel ratio does not take place and in which an increase in the internal resistance results in a drop in the electromotive force to be measured causes the input resistance the side of the circuit exposed to the output voltage of the probe is increased to measure the true electromotive force, however this can be in terms of the insulation ability or safety are not increased as it should, resulting in poor functioning of the oxygen sensor.

It is an object of the present invention to provide an oxygen sensor of the type mentioned above, which avoids the disadvantages mentioned above, which in particular has a long service life with improved reliability, in the is less subject to electrode deterioration, which is free from electrode peeling, which has remarkable measuring performance with a steep increase in electromotive force close to the theoretical air / fuel ratio and which can generate a considerably higher electromotive force. One Another object is to easily manufacture such an oxygen sensor.

According to the invention, this object is achieved with regard to the oxygen sensor by the features in the characterizing part of claim 1 and with regard to the method for producing such an oxygen sensor by the features in the label of claim 11 solved.

Further details and embodiments of the invention are as follows Refer to the description in which the invention is based on the illustrated in the drawing Exemplary embodiments are described and explained in more detail. They show: FIG. 1 a axial section through the basic structure of an oxygen sensor according to an embodiment of the present invention, Fig. 2 is an enlarged partial section through the cell of the Oxygen sensor according to Fig. 1, Fig. 3 to 9 front views of various embodiments of the present invention with different structures of the output voltage generating Electrode, the electrode receiving the output voltage and the one on the outer surface the electrode stiffening formed by the solid electrolyte, Fig. 10 the excess air rate and the electromotive force of the invention Oxygen sensor showing diagram, Fig. 11 a load current and the electromotive force of the oxygen sensor according to the invention Diagram, Fig. 12 shows the thickness of the metal electrode and the service life or the Reaction time of the inventive oxygen sensor representing diagram and 13 shows the thickness of the porous layer and the life or the reaction time of the oxygen sensor according to the invention representing diagram.

The basic structure of the oxygen sensor according to an embodiment The present invention is described with reference to FIGS. 1 and 2.

Referring to Fig. 1, showing the structure of a complete oxygen sensor According to the present invention, a holder 1 holds a sensor cell 2 which Via a spring 4 and a take-off tip 3 for the output voltage on the holder 1 attached and fixed. The cell 2 consists of a cylinder, one of which End is closed and in which the outer surface is close to the closed end with is in contact with the exhaust gas when the sensor is attached to a vehicle, and in which the inner surface is in contact with the atmosphere. The outside the cell 2, which is in communication with the exhaust gas, is covered with a protective cover 5 provided, which consists of a porous or

holey vessel, one end of which is attached to the holder 1 is. At the end facing away from the holder end with the protective cover 5 is an electrical end Arranged insulator 6, which carries an output terminal 7, one end of which is the spring 4 keeps pressed and by the spring 4 and the removal tip 3 to the inner surface the cell 2 formed reference gas electrode electrically passes, whereby a Terminal of the oxygen sensor is formed. The other terminal of the oxygen probe consists of the holder 1 and leads by means of a graphite plate 8, which is between the cell 2 and the holder 1 is placed, to the electrode decreasing the output voltage, which is formed on the outer surface of the cell 2.

Fig. 2 is an enlarged section through the structure of the sensor cell 2 in the area of its closed end. Here, reference numeral 2a denotes one solid electrolyte, which is formed in a cylinder closed on one side. The solid electrolyte 2a can be made of any material having oxygen ion conductivity possesses, for example from ZrO2-CaO.

Instead of ZrO2, HfO2, U02, TiO2 or CeO2 and instead of CaO can also be used MgO, r2o3, Sec203 or Nd203 can also be used.

A suitable part of the outer surface in the area of the closed end of the solid electrolyte 2a is chemically plated so that a metal layer 2b, which forms the electrode generating the output voltage. This electrode 2b may suitably be made of platinum. On a suitable part of the outer surface of the solid electrolyte 2a is the decreasing output voltage Electrode 2c formed by applying a metal paste and sintering it. The electrode 2c is electrical with the output voltage generating electrode 2b tied together. The output voltage generated by the electrode 2b becomes over the graphite plate 8 transferred to the holder 1. Can platinum, gold and palladium individually or used as a mixture for the metal paste.

At least on the outer surface of the one that generates the output voltage Electrode 2b, a layer 2d for electrode stiffening is formed. Is platinum a suitable material for the electrode stiffening layer 2d. The electrode stiffener 2d is additionally provided with a porous layer 2e made of an inorganic substance overdrawn. This inorganic substance can, for example, stabilize ZrO2, Al203 or MgA1204. The appropriate range of composite thickness of the electrodes 2b and 2d is 0.5 to 20 #, that of the thickness of the porous layer 2e is about 5P to 250 r. The reference gas electrode 2f is formed on the inner surface of the electrolyte 2a, which are connected to the output terminal 7 via the removal tip 3 and the spring 4 is. This cited basic structure is referred to in more detail described on the following particular embodiments.

In the first embodiment shown in Fig. 3 extends In the above-mentioned basic structure, the electrode generating the output voltage is located 2b over the entire area of the closed end of the solid electrolyte 2a; the the output voltage decreasing electrode 2c is formed so that it covers almost the entire part of the solid electrolyte 2a except for the area the output voltage generating electrode 2b; and the electrode stiffener 2d extends over the entire outer surface of both electrodes 2b and 2c. Otherwise the structure is the same as described above.

In the second embodiment shown in Fig. 4 extends the output voltage generating electrode 2b over the entire surface the closed end of the electrolyte 2a; the output voltage decreasing Electrode 2c covers almost all of the solid electrolyte part 2a apart from the area of the electrode 2b; and the electrode stiffener 2d is only formed on the outer surface of the electrode 2b. Otherwise the structure is the same as described above.

In the third embodiment shown in Fig. 5 is a A plurality of the output voltage decreasing electrodes 2c on the outer surface of the solid electrolyte 2a formed in longitudinal strips reaching the tip; the output voltage generating electrode 2b is ii the front area of the fixed Electrolyte 2a containing some of the electrodes 2c is formed; and the electrode stiffener 2d is formed only on the outer surface of the electrode 2b. Otherwise the structure is the same as described above.

The fourth embodiment shown in FIG. 6 extends the electrode 2b generating the output voltage over the sent closed Solid electrolyte round 2a; the electrodes that decrease the output voltage 2c are formed in such a way that they adhere to the electrode 2b on the outer surface of the fixed Adjacent electrolyte 2a in the form of catch and longitudinal strips; and the electrode stiffener 2d is formed only on the outer surface of the electrode 2b. Otherwise the structure is the same as the basic structure described above.

The gentle embodiment shown in FIG. 7 is the 1usgangsapannng decreasing electrode 2c as a grid band on the outer surface of the fixed Electrolyte 2a formed; the Elittrode 2b generating the output voltage is of this type formed, deß the outer surface of the solid electrolyte 2a other than the Soder area the electrode 2c covered; and the electrode stiffener 2d is only on the outer surface of the electrode 2t. Otherwise the structure is the same as that described above Basic structure.

In the sixth embodiment shown in Fig. 8 is the the output voltage decreasing electrode 2c as a grid band on the outer surface the solid electrolyte 2a is formed; the electrode generating the output voltage 2b is formed in such a way that it adheres to the outer surface of the solid electrolyte 2a covers the front portion of the electrode 2c; and the electrode stiffener is 2d formed only on the outer surface of the electrode 2b. Otherwise the structure is the same like the basic structure described above.

In the seventh embodiment shown in Fig. 9 is the Output voltage decreasing electrode 2c as a grid band on the outer surface of the solid electrolyte 2a is formed; the output voltage generating electrode 2b covers the outer surface of the solid electrolyte 2a including the front portion the electrode 2c; and the electrode stiffener 2d covers the outer surfaces of both Electrodes 2b and 2c. Otherwise, the structure is the same as that described above Basic structure.

The following is the method of making an oxygen sensor described in accordance with the present invention. First, the solid electrolyte 2a is like described in the examples above. The output voltage decreasing Electrode 2c on the outer surface of the solid electrolyte 2a (except for the part in the area the closed end) is made of gold, platinum, palladium or rhodium paste, which is applied and then heat-treated or sintered. Which is the output voltage generating electrode 2b in the area of the closed end of the solid electrolyte 2a is obtained by chemical plating by immersion in a non-electrolytic one Plating solution containing platinum. The electrode reinforcement 2d on the outer surfaces the Electrodes 2b and 2c are obtained by electroplating, vapor deposition under vacuum, Ion plating or metallizing. The porous layer 2e on the outer surface of the Electrode stiffening 2d is obtained by plasma metallizing the mentioned Al 2 O 3 powder etc. The reference gas electrode 2f is maintained on the inner surface of the solid electrolyte 2a by chemical plating or by applying and heat treating the metal paste. The probe cell 2 produced in this way is in the holder 1, which is a special Has shape held so that the output voltage generating electrode 2b and the holder 1 are electrically connected to each other.

Then the output terminal 7 is provided so that the reference gas electrode 2f and the output terminal 7 are related to each other, whereby the oxygen sensor is created.

Let us now consider the process of making the sensor cell using specific examples are described in more detail.

First, the example of the first manufacturing method is obtained the solid electrolyte 2a by mixing ZrO2 and X203 at a ratio of 90 mol% and 10 moles by using a special grade of reagent and the mixture was fired in air in an electric oven at 13000C for 48 hours will. The mixture is then mixed in a ball mill for about 10 hours; granulated in a spray dryer; then in the form of a probe Rubber printing and loops molded; and finally for 20 hours at 18000C in fired in a gas furnace to give a sintered mass. If 0a0 or MgO is used as a stabilizer, one also obtains a sintered mass through same process described above.

Then, the solid electrolyte 2a, which is a sintered mass of 90 represents moles of ZrO2 and 10 mol% of Y203, well degreased with acetone; through 20 minutes Immersion at 400C in an aqueous solution made of chromium trioxide 50 g / l Sulfuric acid is 100 ml / l and hydrofluoric acid is 100 ml / l; Completely washed off with water, dried; coated with commercially available platinum paste; and then fired with air at 8000C for 20 minutes, which increases the output voltage decreasing electrode 2c is formed. Then the solid electrolyte 2a with the already formed electrode 2c degreased, rinsed with water and left for a few seconds immersed in an aqueous solution of chloroplatinum (IV) acid 5 g / l at room temperature, This is followed by drying at 50 ° C. for 30 minutes. Thereupon the dried solid electrolyte 2a of a nucleation by precipitation (precipitation nucleation) by immersion in a solution of sodium boronate for 10 minutes at room temperature Subject to 3 g / l. After the nucleation by failure, a certain length of the closed end of the solid electrolyte 2a into a non-electrolytic one Plating solution immersed, which is obtained by dissolving 0.25 g of chloroplatinic acid Dissolve in 950 ml of concentrated ammonia water, reduce its volume to 1 1 by diluting with pure water and adding 0.1 g of sodium boranate immediately before use receives.

After leaving this in a bath at 250C for 2 hours, platinum becomes uniform on the outer surface of the front part of the solid electrolyte 2a precipitated or precipitated, whereby the electrode generating the output voltage 2b is generated. After that, electroplating is carried out for 20 minutes, by using a commercially available platinum plating solution (platinum plating solution No. 765, manufactured by Japan Engelhald, Co.) with a platinum concentration of 12 g / l, an electrical current density of 0.8 A / dm2 and a bath temperature of 800C and a pH of 12.5 is applied. This creates a 2> i film of the platinum plating, i.e., the electrode stiffener 2d. It then becomes aluminum oxide powder plasma-metallized, which provides a porous layer 2e about 100 μm thick. the Plasma metallization is done with a plasma arc current of SOO A, an arc voltage of 65 V, the flow rates of the gases being equal to 100 SCFH (about 2.83 m3 / h) for N2 and 15 SCFH (about 0.42 m3 / h) for H2 is the flow rate for the powder feed gas N2 is 37 SCPH (about 1.05 m3 / h) and the powder feed rate is 12.5 1b / h (about 2.5 kg / h).

In the above process, the order in which the Platinum phase, the non-electrolytic plating after etching, washing and Drying follows, also being reversed, without affecting the characteristics of the oxygen probe be adversely affected.

An oxygen sensor equipped with a sensor cell, which is made according to the method of the first example is hereinafter referred to as sample or sample A.

In the second example, the electrode stiffener 2d becomes the first For example, instead of electroplating with platinum as in the first example Vacuum vapor deposition formed, the conditions for vacuum vapor deposition at a pressure of 1x10-4 Torr, a precipitation distance of 150 mm and one Rainfall time of 15 minutes exist. An oxygen sensor obtained in this way is hereinafter referred to as a sample or

Sample B.

In the third example, the electrode stiffener is 2d instead of dlrch Electroplating, as in the first example, formed by ion plating, where the conditions of ion plating in a pressure of 2x10 4 Torr, a deposition distance of 150 mm, a bias voltage of 3 KV, a precipitation time of 30 minutes and an electron beam current of 200 mA. That way you get an oxygen sensor, hereinafter referred to as Sample C.

For comparison, a sample or sample D is used accordingly the method in the first example platinum electrodes of about 0.5 P thickness by non-electrolytic Plating formed on both sides of the solid electrolyte 2a and immediately an alumina powder coating is then applied in the same manner as in the first example plasma-metallized.

Using samples A, B, C, and D, the characteristics the oxygen sensor of the present invention and conventional type for comparison examined.

First of all, the test conditions were defined as follows: 2000 cc machine, 2500 rpm, suction pressure of 350 mmHg, unleaded gasoline as fuel and duration 200 hours.

It should also be explained that in FIGS. 10 and 11 the characteristics of the for Comparison manufactured sample D were included in two ways, namely once as "sample D" after the above-mentioned long-term test, as well as those according to the invention Samples A, B and C, and on the other hand also as "comparative sample D '" before the endurance test. The comparative sample D 'was thus in contrast to the Samples A - D not subjected to the long-term test.

First, the characteristic of the excess air rate ()) became dependent studied by the electromotive force.

During the test, the oxygen sensor was kept at 5000C; a gas mixture containing 1% 112 and 99% N2 per unit volume was used in a Rate of 2000 cm3 / min introduced on the side of the gas to be measured; in one The range of excess air rates 2 = 0 to 3 with the addition of air became the electromotive Force of the probe measured with a voltmeter of 1000 Md input impedance; these Results are summarized in FIG. As can be seen from Fig. 10, is in the oxygen sensor of the present invention, electrode deterioration less than the conventional sample D; a higher voltage is generated; and the increase in the electromotive force in the range of the theoretical air / fuel ratio is steeper. This shows that the performance or the behavior of the oxygen sensor according to the present invention is excellent.

The load characteristic of the oxygen sensor was then examined. During the experiment, the sensor was kept at 5000C; a gas mixture containing 1% Containing H2 and 99% N2 per unit volume, was added at a rate of 2000 cm3 / min initiated on the side of the gas to be measured; variable resistors were on connected to both ends of the probe; with changed resistance became the The terminal voltage of the probe was measured with the voltmeter mentioned above.

As can be seen from Fig. 11, in which the results are summarized is the voltage drop even if a load resistor is connected very low. The drop in measured voltage was negligible, even than the probe was connected to a voltage measuring circuit, which is included in the system.

After that, the effect of changing the thicknesses of the metal electrodes (2b and 2d) and the porous layer 2e examined for the reaction characteristic of the sample A. The reaction time, which is the electromotive force of the sensor, is examined it takes to reach 0.8 V when the air / fuel ratio of the exhaust gas is abrupt was changed from 15.5 to 14.0 with a 2000cc machine operating at 2500 rpm is operated, a suction pressure of 350 mmHg and a sensor temperature of 650 ° C was provided. These response times were taken as the response curve.

The results are summarized in FIGS. 12 and 13, the Ordinate the reaction time, the abscissa the thickness of the metal electrode or the porous layer and the line connecting the characters, connecting #, the characteristic curve is. As can be seen therefrom, the thickness of the metal electrode is preferable less than 20, while that of the porous layer is preferably less than 250 μ is.

Next, using Sample A, the effect of the changed Thicknesses of the metal electrodes (2b and 2d) and the porous layer 2e on the sensor life examined. In the investigation, the time was taken that the electromotive Force of the probe required for a drop below 0.55 V, with a 2000 cc machine with 2500 rpm, suction pressure of 350 mmHg, a sensor temperature of 650 0C and a The air / fuel ratio of the exhaust gas was provided equal to 14.0. This time was taken as lifetime.

The results are summarized in Figures 12 and 13, in which the ordinate the service life, the abscissa the thickness of the metal electrode or the porous layer, and the line connecting the characters 0 is the characteristic curve represents. As can be seen therefrom, the thickness of the metal electrode is preferable greater than 0.5, while that of the porous layer is preferably greater than 5.1.

From the reaction or response time and the service life characteristics it can be seen that the thickness of the metal electrodes (2b and 2d) is preferably at 0.5 to 20 p, while that of the porous layer 2e / preferably 5 to 250 microns lies.

On the basis of this structure and the characteristic curves, the inventive Oxygen probe the following performances are expected: a) Because the electrode deterioration is small and there is hardly any electrode detachment, the oxygen sensor has an extended service life and increased reliability.

b) Since the increase in the electromotive force by the theoretical The air / fuel ratio is steep, the sensor has an excellent one Measuring property.

c) The electromotive force generated is far greater than that generated by a conventional oxygen probe.

d) The thickness of the metal electrode can be 0.5 to 20> i and the of the porous layer are from 5 to 250.1.

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Claims (12)

Title: Oxygen sensor and method for its manufacture Patent claims 1.) Oxygen sensor with a solid electrolyte in the form of a closed one End provided cylinder made of an oxygen ion conductive material, with a Reference electrode on the inner surface of the solid electrolyte and with another Electrode on the gas measuring surface of the solid electrolyte, one of which electrodes Output signal is picked up, characterized in that the electrode on the Gas measuring surface of the solid electrolyte (2a) on a generating an output voltage Electrode (2b) made by chemical plating at a suitable location on the outer surface formed at least in the area of the closed end of the solid electrolyte (2a) is composed of an output voltage decreasing electrode (2c) coated with a metal paste so formed at a suitable location on the outer surface of the solid electrolyte (2a) is that it is electrically connected to the output voltage generating electrode (2b) is connected, and is composed of an electrode stiffener (2d) which on the outer surface of at least the electrode generating the output voltage (2b) is provided, and that a porous layer (2e) made of an inorganic substance is formed on the outer surface of the electrode stiffener (2b). 2. Oxygen sensor according to claim 1, characterized in that the combined thickness of the output voltage generating electrode (2b) and the the output voltage decreasing electrode (2c) or the electrode stiffener (2d) is about 0.25 to 20 p. 3. Oxygen sensor according to claim 1 or 2, characterized in that that the thickness of the porous layer (2e) is about 5 to 250 r. 4. Oxygen sensor according to one of claims 1 to 3, characterized in that that the output voltage generating electrode (2b) covers the entire surface of the closed front end of the solid electrolyte (2a) covers that the Output voltage decreasing electrode (2c) the entire surface of the solid electrolyte (2a) except for the area of the output voltage generating electrode (2b) essentially covers and that the electrode stiffener (2d) the entire surface of both electrodes (2b, 2c) covered (Fig. 3). 5. Oxygen sensor according to one of Claims 1 to 3, characterized in that that the output voltage generating electrode (2b) covers the entire surface of the closed front end of the solid electrolyte (2a) covers that the Output voltage decreasing electrode (2c) the entire surface of the solid electrolyte (2a) covered except for the area of the electrode (2b) generating the output voltage and that the electrode reinforcement (2d) on the outer surface excluding the die Output voltage generating electrode (2b) is formed (Fig. 4). 6. Oxygen sensor according to one of claims 1 to 3, characterized in that that the output voltage decreasing electrode (2c) has the shape of a plurality of Has longitudinal strips that attach to the tip of the outer surface of the solid Electrolyte (2a) close to that of the electrode generating the output voltage (2b) on the outer surface of the front end of the solid electrolyte (2a) except in the Area of the output voltage decreasing electrode (2c) is formed and that the electrode stiffener (2d) on the outer surface excluding the output voltage generating electrode (2b) is provided (Fig. 5). 7. Oxygen sensor according to one of claims 1 to 3, characterized in that that the output voltage generating electrode (2b) covers the entire outer surface of the closed front part of the solid electrolyte (2a) covers that the Output voltage decreasing electrode (2c) to the output voltage generating Electrode (2b) formed adjacent as a plurality of circumferential and longitudinal strips is, and that the electrode stiffener (2d) on the outer surface exclusively the the output voltage generating electrode (2b) is formed (Fig. 6). 8. Oxygen sensor according to one of claims 1 to 3, characterized in that that the output voltage decreasing electrode (2c) as a grid band on the outer surface of the solid electrolyte (2a) is formed that the output voltage generating Electrode (2b) on the outer surface of the front part of the solid electrolyte (2a) except in the area of the electrode (2c) decreasing the output voltage and that the electrode stiffener (2d) only on the outer surface of the output voltage generating electrode (2b) is formed (Fig. 7). 9. Oxygen sensor according to one of claims 1 to 3, characterized characterized in that the output voltage decreasing electrode (2c) has the shape of a Grid tape on the outer surface of the solid electrolyte (2a) has that the Output voltage generating electrode (2b) the entire outer surface of the fixed electrode tip including the area of the output voltage receiving electrode (2c) covered and that the electrode stiffener (2d) only on the outer surface of the Output voltage generating electrode (2b) is formed (Fig. 8). 10. Oxygen sensor according to one of claims 1 to 3, characterized characterized in that the output voltage decreasing electrode (2c) has the shape a grid tape on the outer surface of the solid electrolyte (2a) has that the output voltage generating electrode (2b) covers the entire outer surface of the fixed Electrode tip including the area where the output voltage is decreasing Electrode (2c) covered and that the electrode stiffener (2d) on the outer surfaces both electrodes (2b, 2c) is provided. (Fig. 9). 11. A method for manufacturing an oxygen sensor according to a of the preceding claims, wherein by firing a cylinder with a closed A solid electrolyte is made from a material that conducts oxygen ions is, on the outer and inner surface of which an electrode is applied, g e k e n n z e i c h n e t through the following 8 steps: a) Formation of an output voltage decreasing electrode (2c) by applying and heat treating a metal paste at a suitable location on the outer surface of the solid electrolyte (2a); b) Form an output voltage generating electrode (2b) by chemical plating at a suitable point on the outer surface of at least the closed end of the solid electrolyte (2a); c) Forming an electrode stiffener (2d) on the outer surface of at least the output voltage generating electrode (2b) by vacuum vapor deposition, electroplating, ion plating or metallizing, d) forming a porous layer (2e) of an inorganic substance on the outer surfaces the electrodes (2b, 2c); e) forming a reference gas electrode (2f) on the inner surface of the solid electrolyte (2a) by chemical plating or by applying and Heat treating a metal paste; f) secure fixing of the solid electrolyte (2a) together with the electrodes (2b - 2f) on its inner and outer surface in one Holder (1) in such a way that the electrolyte (2a) with the output voltage generating electrode (2b) can be electrically connected; and g) providing one Output terminal (7) for electrical connection to the reference gas electrode (2f). 12. The method according to claim 11, characterized in that the The order of applying the metal paste and chemical plating is concerned Process steps a) and b) can also be reversed. - End of claims -