Abstract: An oxygen sensor utilizes a chrome oxide compensating resistor (5) in series with a titania sensing resistor (3). The chrome oxide resistor (5) not only compensates for the effects of temperature on the titania sensing (3) resistor, but since it exhibits (p) type behavior while the titania exhibits (n) type behavior in the presence of gaseous oxygen, the sensitivity of the sensor is increased. The resistors (3, 5) can be applied as a film to a substrate (7) or they can be formed as discrete chips. Substantial quantities of alumina and glass can be added to the chrome oxide without affecting oxygen sensitivity although the electrical resistance rises substantially.

Abstract: An oxygen sensor (1) for detecting the oxygen content of an internal combustion engine exhaust gas system includes a generally cylindrical hollow insulator (3) having a first resistive element (17), preferably of titania, and a second resistive element (19) preferably of zirconia or chromia, adjacent the closed end (9) thereof, grooves (23) adjacent the open end (7) thereof, and an intermediate portion (11) having a shoulder (13), with electrically conductive film leads (29) passing over the surface of the insulator (3) between the resistive elements (17 and 19) and the grooves (23), with a dielectric coating (33) over the conductive film leads (29) in the area of a metal shell (31) to insulate the film leads (29) from the shell (31).

Abstract: The invention is a method of making a pressure tight seal for a glow plug characterized by applying a high current to heat a groove (31) in the outer shell (3) of a glow plug while simultaneously pressing together the sealing elements adjacent the groove i.e. an insulator (2), a gasket (1), the flared end (42) of a protective tube (4) and a shoulder (32) within the shell (3). The grooves (31) concentrates the heat and allows the shell to be compressed around the elements of the seal.

Abstract: A temperature compensated resistive oxygen sensor and a method of manufacturing the same. On the surface of the sensor there are disposed in spaced relation three electrodes. One electrode and a portion of a second electrode is completely covered by a layer of a resistive material which is sensitive to changes in temperature. Another layer of resistive material which is sensitive to both changes in temperature and changes in the partial pressure of oxygen in the gas to which it is exposed covers the first resistive layer as well as the third electrode and the remaining portion of the second electrode. It is also a feature of the present invention that these layers are applied by shielding part of the surface of the sensor and applying the first layer by a hot thin-layer technique and by removing the shield and applying the second layer also by a hot thin-layer technique.

Abstract: An activated solid electrolyte oxygen gas sensing element with increased voltage output, shortened switching time and reduced internal resistance, the sensing element having inner and outer conductive catalyst electrodes thereon, is produced by subjecting the outer surface with the outer electrode to a nonoxidizing atmosphere and applying a direct current to the element while the same is at an elevated temperature, the current being applied with the outer electrode as an anode.

Abstract: A temperature compensated resistive oxygen sensor and a method of manufacturing the same. On the surface of the sensor there are disposed in spaced relation three electrodes. One electrode and a portion of a second electrode is completely covered by a layer of a resistive material which is sensitive to changes in temperature. Another layer of resistive material which is sensitive to both changes in temperature and changes in the partial pressure of oxygen in the gas to which it is exposed covers the first resistive layer as well as the third electrode and the remaining portion of the second electrode. It is also a feature of the present invention that these layers are applied by shielding part of the surface of the sensor and applying the first layer by a hot thin-layer technique and by removing the shield and applying the second layer also by a hot thin-layer technique.

Abstract: A method and apparatus for obtaining an electrical signal which is a function of the 0.sub.2 content of the exhaust gas of an internal combustion engine. Two resistors (1 and 3) are exposed to the exhaust gas of an internal combustion engine. Both resistors (1 and 3) have a resistance which varies as a function of the temperature of the exhaust gas to which it is exposed. However, the resistance of one of the resistors (1) also varies as a function of the oxygen content in the exhaust gas. Therefore, by applying a voltage to the resistors an electrical signal can be obtained which is a function of the O.sub.2 content of the exhaust gas, with the temperature effect of the exhaust gas on the network output being minimized or eliminated. The resistors (1 and 3) that form the sensing elements (10) are connected in series to other resistors to form a first and second resistor network which is connected together in parallel circuit relationship.

Abstract: A temperature compensated oxygen sensor has a generally cylindrical first insulator with an axial bore extending therethrough which is counterbored at one end. A second cylindrical insulator is retained in the bore in the first insulator either by a radial inwardly directed flange on the second end of the first insulator or by a radial outwardly directed flange on one end of the second insulator which seats in the counterbore of the first insulator. A titania resistor and a compensating resistor are mounted on the second end of the second insulator by leads extending through longitudinal bores in a second cylindrical insulator and into the counterbore in the first insulator. The leads are connected to terminals which are retained in the counterbore either by a chemical bonding agent or by a third cylindrical insulator through which the terminals extend. The third insulator can be secured either by mechanical means and/or by a chemical bonding agent including a glass preform.

Abstract: The helical compression spring which completes the electrical circuit between the interior surface of a tubular ion conductive solid electrolyte gas sensing element closed at one end, and an electrical terminal retained in spaced relation to the open end of the sensing element is close wound adjacent the end exposed to temperatures which would cause open coils of the spring to relax and has a compressed length sufficient to maintain a preselected minimum force against the terminal and sensing element over the full range of operating temperatures to which the sensor is exposed. In an alternate embodiment of the invention, this spring is provided with a closely wound portion at each end so that the sensor can be assembled by inserting the spring either end first.

Abstract: An activated oxygen gas sensor element having an increased voltage output under rich gas conditions, short switching response and reduced internal resistance is produced by chemically treating the inner conductive catalyst electrode of the sensor element with an inorganic acid or acid salt and current activating the outer conductive catalyst electrode by applying a direct current to the sensor element, with the outer electrode as a cathode, while the outer electrode is at an elevated temperature and in the presence of a neutral or inert atmosphere. Air may be used as the atmosphere in contact with the outer electrode during the current activation provided that the sensor is subjected to a subsequent reheating step to provide the desired results.

Abstract: A solid electrolyte oxygen gas sensor element 1 comprises an electrolyte body 3 having electrodes 7 and 11 on the outer and inner surfaces 5 and 9 thereof, with the inner surface 9 having a protective means 13 thereon to protect the same from contact with oxygen or oxygen-containing gases so as to provide a substantially zero oxygen reference for the inner surface. The protective means 13 can comprise a coating, or a packing within a tubular electrolyte body, of carbon or a metal which forms an oxide that is stable at the operating temperature of the oxygen sensor element.

Abstract: An activated oxygen gas sensor element having an increased voltage output under rich gas conditions, short switching response and reduced internal resistance is produced by chemically treating the inner conductive catalyst electrode of the sensor element with an inorganic acid or acid salt and current activating the outer conductive catalyst electrode by applying a direct current to the sensor element, with the outer electrode as an anode, while the outer electrode is at an elevated temperature and in the presence of a nonoxidizing atmosphere.

Abstract: An oxygen sensor having a removably mounted shield (10) to protect the solid electrolyte tube (30) that extends from the sensor housing (20). In one embodiment of the invention the protective shield (10) includes a radially extending lip (12) that is snapped into an undercut (21) in the sensor housing (20).

Abstract: A method and apparatus for measuring the O.sub.2 content in an exhaust gas of an internal combustion engine by exposing two resistors to the exhaust gas of an internal combustion engine. The resistance of both resistors varies as a function of the temperature of the exhaust gas to which it is exposed. However, the resistance of one of the resistors also varies as a function of the oxygen content of the exhaust gas. Therefore, an electrical signal can be obtained which is a function of the O.sub.2 content of the exhaust gas, with the temperature effect of the exhaust gas on the resistor being minimized or eliminated.

Abstract: An oxygen gas sensor having a solid electrolyte oxygen gas sensor element, with an inner conductive catalyst electrode on the interior surface and an outer conductive catalyst electrode on the exterior surface thereof, which has a high voltage output and lower internal resistance is produced by chemically activating said inner conductive catalyst electrode with an inorganic acid or an acid salt. By also subjecting said outer conductive catalyst electrode to a direct current activation under a reducing atmosphere, even more improved properties, such as fast switching response, are achieved.

Abstract: A wide range combustion mixture air/fuel ratio sensor in which an electrochemical cell supplies hydrogen gas to a palladium sensor element at a rate regulated by the output of a Wheatstone bridge circuit incorporating the sensor element. This generated hydrogen gas combines with any oxygen present in the exhaust gas through catalytic action and also maintains the level of absorbed hydrogen, and therefore the electrical resistance of the palladium sensor element, at a preselected value. The magnitude of the current applied to the electrochemical cell necessary to maintain this balance is a measure of the combustion mixture air/fuel ratio.

Abstract: A solid electrolyte oxygen sensing device, and a method for making the same, wherein an electrolyte wafer is sealed within a ceramic insulator by the shrinkage of the ceramic insulator when it is fired. The wafer is formed from an electrolytic material and is fired. The vitrified wafer is placed in a recess in the unfired ceramic insulator and the insulator is then fired, with the resulting shrinkage of the insulator material sealing the wafer in place.

Abstract: A zirconia type oxygen partial pressure sensor for use with an exhaust system wherein an electrical voltage signal is generated in response to an oxygen partial pressure differential across a solid electrolyte. A reference oxygen partial pressure is introduced into the interior of a solid electrolyte sensor through an aperture formed in a housing for the sensor, a protective clip, wire mesh or spring being provided to at least partially cover the aperture to preclude contaminants from being introduced to the interior of the sensor through the aperture. A ground terminal assembly is also provided to supply a ground for the device in addition to that provided by the threaded engagement between the shell of the O.sub.2 sensor and the exhaust system to which it is attached.

Abstract: A solid electrolyte sensor for sensing oxygen in exhaust gases having a solid electrolyte body of a thimble-like design with an inner conductor thereon and a nonreactive but compatible bonding layer of magnesium or calcium oxide over the outer surface of the electrolyte body and a conductive catalyst layer superimposed on the bonding layer.

Abstract: A solid electrolyte oxygen sensor has a protective coating to protect a catalyst or conductive film thereon, which coating is formed as an inorganic reaction product of an oxide material and an inorganic acid which forms a matrix to bond the oxide material as an adherent coating over the film.