Abstract: Apparatus for sensing oxygen concentration using a solid electrolyte of cylindrical shape, with a heater disposed within the solid electrolyte, is disclosed. The member supporting the heater, and the leads for the heater, are integrally bonded to the heater through an inorganic bonding member such as glass. By integrally bonding the support member and leads through an inorganic bonding member, the heater length can be reduced.

Abstract: An oxygen sensor, suited for measuring the concentration of an oxygen gas contained in an exhaust gas of an automobile, comprises a cell and a heater which is mounted for heating the cell. The heater, including an electrically insulating substrate and a heating element embedded in the substrate, has a recess on one surface thereof and a pair of side wall portions formed by forming the recess. The cell comprises a solid-electrolyte body, a detection electrode, a reference electrode and a chamber enclosing the reference electrode except for its opening. The cell is disposed in the recess of the heater and joined to the heater with an intermediate layer being disposed between the cell and the heater and sintered. The intermediate layer has a number of fine cracks and an intermediate thermal expansion coefficient between these of the solid-electrolyte and the substrate.

Abstract: An oxygen sensor for monitoring the oxygen concentration in exhaust gases of an engine of a motor vehicle including a sensor element supported by a base in a position remote from the flow of exhaust gases to be tested whereby solid particles in the exhaust gases are prevented from being deposited on the sensor element and the sensor element is imprevious to influences exerted by the temperature and flow velocity of the flow of exhaust gases. The oxygen sensor is capable of stably monitoring the oxygen concentration in exhaust gases of an engine of a motor vehicle with a high degree of performance over a prolonged period of time.

Abstract: A thermal air flow meter is equipped with a flow rate detector utilizing the phenomenon that heat is carried away in proportion to flow rate. The flow rate detector comprises a support, a heat-sensitive resistor formed on the support and leads attached to both ends of the support. To make the temperature distribution uniform, the heat-sensitive resistor is formed in such a manner that the resistance per unit length of the heat-sensitive resistor at either end of the support is greater than the resistance per unit length of the heat-sensitive resistor at the center of the support. This arrangement can provide a thermal air flow meter which has a rapid response to changes in flow rate.

Abstract: The current flowing through a thermosensitive element is amplified and output as a signal indicating its magnitude. The signal is processed by being converted into a digital signal and is used to calculate, for example, the quantity of fuel that should be supplied for the thus measured quantity of intake air in an internal-combustion engine. The current is supplied to the thermosensitive element from the positive electrode of a power source, and returns to the negative electrode thereof via a return line. The return line and a ground potential line of the amplifier are separate lines. The magnitude of the current flowing through the thermosensitive element is varied by varying the potential of a point on the return line accordingly. Because the return line and the ground potential line are separate, the ground potential can be kept constantly stable.

Abstract: Air flowing through an air cleaner is passed through a main passage and drawn into an internal-combustion engine, with a part of the air flowing through the main passage flowing into a by-pass passage having an air flow sensor mounted therein. A length of the by-pass passage is substantially three or more times longer than that of a part of the main passage corresponding thereto. Accordingly, even when the internal-combustion engine is operated with a throttle nearly totally open and the air in the main passage is pulsated, the average flow rate in the by-pass passage increases due to the inertial lag effect obtained by lengthening the by-pass passage, so that it is possible to prevent the output of the flow sensor from being undesirably lowered.

Abstract: An air flow rate measuring apparatus in which an air flow sensor whose electric characteristic varies with the rate of air flowing by the sensor is supported on a heat-insulating support member and located in a bypass tube provided in the vicinity of the main venturi of an internal combustion engine, whereby the air flow sensor is isolated from adverse thermal influences so as to reduce an error in measuring air flow rate.

Abstract: A thermal air flow meter consists essentially of a hollow cylindrical support made of an insulating material, a heat-sensitive resistor formed on top of the support, and lead wires inserted into the hollow part of the support from either end and bonded thereto by glass. This flow meter measures the flow rate from changes in the resistance of the heat-sensitive resistor with temperature. The ratio of the inner diameter d.sub.2 of the support to the outer diameter d.sub.3 of the lead wires (d.sub.2 /d.sub.3) is at least 1.7. This arrangement can provide a thermal air flow meter with a quick response to changes in flow rate.

Abstract: A combustion sensing apparatus having a solid electrolyte disposed in the vicinity of a burner and having a tabular form. Thanks to the tabular form of the solid electrolyte, the production of the apparatus is very much facilitated and the areas occupied by the anode and cathode are minimized. The construction of the apparatus as a whole is simplified and the reliability of the same is improved remarkably. In addition, the cost of production is lowered advantageously.

Abstract: A flow rate sensor having an annular passage for enabling a flow of liquid therethrough and a movable member disposed in the annular passage. An intake passage is provided for supplying liquid to the annular passage and an outlet passage, disposed concentrically to the intake passage, enables the liquid to flow out of the annular passage about an outer periphery of the intake passage.

Abstract: An air flow rate measuring apparatus having an air flow sensor and a temperature sensor which are disposed in a passage for intake air formed in the vicinity of a main air flow guide chamber in an internal combustion engine. The electric characteristics of the air flow sensor vary with the flow rate of air flowing by the sensors. The air flow sensor and temperature sensor have the same shape and the same construction. The temperature sensor is used to compensate the temperature of the air flow sensor so as to maintain the air flow sensor at a predetermined temperature. These sensors are arranged in the same plane that is at right angles to the direction in which said intake air flows. The sensors are extended parallel to each other in symmetrical relationship with respect to the center line in the above-mentioned plane. Conductor support pins to which the sensors are fixed are also arranged symmetrically with respect to the center line in the mentioned plane.

Abstract: An intake barrel connected to an intake pipe of an internal combustion engine is provided therein with a venturi member. Openings are formed in the wall of the intake barrel at the upstream and downstream sides of the venturi member. A bypass passage forming member provided with a groove of a length greater than the distance between said openings is fixed to the outside of the intake barrel. A bypass passage is formed by these openings and the groove. A spacer is interposed between the intake barrel and the bypass passage forming member. The cross-sectional area of the bypass passage can be varied by varying the thickness of the spacer.

Abstract: An air flow rate sensor including a resistor the characteristic of which depends on temperature for operation mounted in a suction conduit of an internal combustion engine. The air flow rate sensor includes a tube of inorganic material, a platinum wire wound in convolutions on the surface of the tube, and a glass coating applied at least to the surface of the resistor while allowing a part of the surface to be exposed. The glass coating has a thickness smaller than the diameter of the resistor wire and enables equalization of pulsations of the sensor output to be obtained because of the thermal capacity of the glass coating.

Abstract: An air intake apparatus for the internal combustion engine is disclosed comprising a heating resistor placed in a bypass for passing the air of an amount in a predetermined ratio to the amount of the air passing through a main air path communicating with the internal combustion engine, the bypass circumventing or detouring the main air path. The bypass body for defining the bypass is made of a synthetic resin material in order to prevent heat conduction to the heating resistor from an external source.

Abstract: A sensor for detecting a fluid flow velocity or flow amount with high precision and high reliability is made by applying a conductor paste comprising platinum powder and an organic vehicle to the outer surface of a fine inorganic insulating tube, followed by drying and firing, thereby forming a platinum film, processing the platinum film into a spiral band form by laser application, inserting a lead wire into the insulating tube, applying a platinum conductor paste to between the spiral platinum band and the lead wire, followed by drying and baking, thereby connecting the spiral platinum band film to the lead wire.

Abstract: A first cylindrical member formed of an ion-conducting solid electrolyte is sealed at one end thereof by a discal plate and inserted at the other end thereof into an axial central bore, formed in a supporting member, in such a manner that the other end of the first cylindrical member is in airtight contact with an offset portion formed in an inner wall surface of the supporting member defining the axial central bore. The first cylindrical member has a first electrode formed on its inner wall surface and a second electrode formed on its outer wall surface. First and second conductors are formed at upper end portions of the first and second electrodes respectively. A second cylindrical member closed at its bottom and housing therein the first cylindrical member in enclosing relationship supports the latter at its bottom and is rigidly secured at its upper end to the supporting member.

Abstract: A protective layer of zirconia particles having particle sizes of 0.5-5 .mu.M is provided on a surface of an electron-conducting layer of an oxygen sensor at a side of a gas whose oxygen concentration is to be detected to a thickness of 4-100 .mu.M by bonding zirconia particles to one another and the first electron-conducting layer by 10-30% by weight of a high melting point adhesive, such as powders of borosilicate glass, based on total weight of the zirconia particles.

Abstract: A liquid level detecting apparatus comprises a thermistor adapted to generate heat by current flowing therethrough, wherein the liquid level is sensed by detecting a current value at the thermistor which varies in dependence on a variation in temperature of the thermistor, which temperature in turn varies in dependence on whether the thermistor is immersed in the liquid or exposed to air. A relay coil is provided in series to the thermistor and disposed within a casing together with the latter so that the variation in temperature of the liquid may be transmitted to the relay coil, wherein the variation in the current value at the thermistor caused by the temperature variation of liquid is corrected by the variation of the resistance of the relay coil.

Abstract: A sensor is provided for electrochemically detecting the oxygen concentration of exhaust gas from an internal combustion engine of a vehicle. The sensor has an oxygen ion-transferrable solid electrolyte partition wall having catalyst electrodes on both sides in its housing, to thereby separate the housing into a reference gas contact compartment and an exhaust gas contact compartment in a hermetically isolated state between the two compartments. The reference gas contact compartment is sealed off from the surrounding atmosphere, but communicates with the atmosphere at a desired location in the vehicle only through an extended passage for introducing air as the reference gas into the reference gas contact compartment. The solid electrolyte partition wall is protected from splashing of water droplets, and consequently from quenching, ensuring an increased durability or life of the sensor without damage.

Abstract: A high-temperature detecting apparatus most suitably used with a system for protecting a catalytic apparatus provided for purifying exhaust gas of an automobile is disclosed. A reed relay coil is connected between the cold junctions of a thermocouple in such a manner that the reed relay is driven directly by an electromotive force generated in the thermocouple due to heat in the exhaust gas. The thermocouple and the reed relay are integrally arranged by means of a metal cover. This arrangement reduces the connection resistance between the thermocouple and the coil, thereby making it possible to directly drive the reed relay by the output of the thermocouple.