Kabushiki Kaisha Toyota Chuo Kenkyusho

Other

Yazaki Corporation

Toyota Jidosha Kogyo Kabushiki Kaisha

Keiichi Saji

Hideaki Takahashi

Haruyoshi Kondo

Takashi Takeuchi

Kiyoharu Hayakawa

Tadashi Inaba

Jiro Sakata

Tadashi Nakamura

Yumi Masuoka

Takayuki Suzuki

Toshitaka Saito

Akio Tanaka

Yasuhiro Otsuka

Masaharu Takeuchi

Toshinobu Furutani

Koji Moriya

Mari Okazaki

Shigeo Suzuki

Toshihiro Ozasa

Hozumi Futata

Kozo Satta

Takahiro Sako

Electrode having high activity to oxygen gas and low activity to flammable gas is provided. An oxygen pump includes oxide-ion conductive solid electrolyte, electrodewhich is an inactive electrode, and active electrode. Electrodeis an electrode that includes CeSmO. Electrodeis disposed on the gas detection chamberside of solid electrolyte. Active electrodeis disposed on the open space side of solid electrolyte. Gas detection chamberis an enclosed space defined by solid electrolyte, insulation layers, and diffusion control layer

Electrodes, electrochemical elements, gas sensors, and gas measurement methods

A NO gas detecting apparatus including an oxygen pumping cell for removing oxygen from a measurement gas, and a NO detecting cell positioned downstream from the oxygen pumping cell to detect concentration of NO in the measurement gas, the NO detecting cell being configured to measure current which flows when oxygen generated from reducing NO is pumped, wherein the NO detecting cell has a NO detecting cathode made of an electrode material including at least one alloy selected from the group consisting of a Pt-Pd alloy, a Pt-Au-Pd alloy, and a Pt-Pd-Rh alloy.

NOx gas detecting apparatus

An oxygen sensor of a limiting current type includes a sensing element coated with a porous coating layer having a catalyst supported thereon. The catalyst includes at least one element selected from the group consisting of platinum, rhodium, palladium, iridium and ruthenium, and the content of the catalyst is not more than 50 wt % with respect to the total weight of the porous coating layer, and particles of the catalyst are dispersed within the porous coating layer at spacings of not more than 6 .mu.m. By using the catalyst, the influence of hydrocarbons to the oxygen concentration is reduced.

Limiting current type oxygen sensor

A thin film mutilayered air-fuel ratio sensor having a sensor element including a first electrode formed on a porous substrate, a first solid electrolyte and a third electrode formed on the first electrode in this order, in such a manner that the first electrode is completely covered by the first solid electrolyte inclusive of its surroundings, and that the first solid electrolyte is completely covered by the third electrode inclusive of its surroundings, a second solid electrolyte and a fourth electrode and formed on the third electrode in this order, in such a manner that the peripheral portion of the third electrode is left uncovered by the second solid electrolyte and the fourth electrode and thereby left exposed. The first electrode, the third electrode, and the fourth electrode are made of a gas-permeable porous platinum, and the first solid electrolyte and the second solid electrolyte are made of a gas-permeable dense solid electrolyte having oxygen ion conductivity. The sensor has far improved performance as compared to the conventional ones and can be made compact.

Thin film multilayered air/fuel ratio sensor

An operation control system for an engine using alcohol fuel or mixed fuel of alcohol and hydrocarbon, or for an engine supplying cooling liquid such as alcohol, water or the like as fuel. Vapor concentration in exhaust gas and an air excess ratio of air-fuel mixture are detected, and a supply rate of alcohol, a water absorption ratio of alcohol or an amount of the cooling liquid is computed on the basis of the vapor concentration and the air excess ratio. Ignition timing, temperature of the coolant, a compression ratio and an air excess ratio are controlled on the basis of the supply rate of alcohol or the water absorption ratio of alcohol. Further, the cooling liquid is supplied which has its amount computed at a heavy load. Thus, operational performance of the engine is improved.

Operation control system for internal combustion engine

An air/fuel ratio sensor has a porous alumina substrate, a limiting current type oxygen detecting section on the porous alumina substrate for detecting the air/fuel ratio in the fuel lean region, a resistance-variable type oxygen detecting section on the porous alumina substrate for detecting the excess air ratio .lambda. when .lambda. is equal to one, a gas decomposition type hydrogen detecting section on the porous alumina substrate for detecting the air/fuel ratio in the fuel rich region and a heater for heating the respective detecting sections to the optimum temperature in operation, whereby the sensor can detect the air/fuel ratio over all the fuel rich and lean regions. In addition the apparatus includes a comparing/discriminating section for comparing the output of the resistance-variable type oxygen detection section with a reference value to discriminate whether the ambient atmosphere is in either of the fuel rich or lean region, a switching control section for changing each of the limiting current type oxygen detecting section from its operative position to its inoperative position or vice versa, depending on the result from the comparing/discriminating section, and an output signal adding section for adding the output signals from both the detecting sections to generate an output signal representative of an air/fuel ratio.

Wide-range air/fuel ratio sensor and detector using the same

This oxygen concentration detector employs an oxygen concentration sensor provided with a plate produced of a material which exhibits ionic conduction for oxygen (An oxygen ionic conductor), a cathode placed on the one surface of the oxygen ionic conductor plate, an anode placed on the other surface of the oxygen ionic conductor plate, and a porous material layer which functions to regulate the flow of oxygen which passes through the porous material layer to reach the cathode and the oxygen ionic conductor plate. The improvement realized in this oxygen concentration detector is to remove a drawback in which the output of this sensor makes an error depending on the temperature of a gas of which the oxygen concentration is measured. This oxygen concentration detector is provided with a limiting electric current type oxygen concentration sensor, a means for applying a voltage to the sensor for the purpose to measure a limiting current flowing in the sensor, a means for measuring a current which flows in the sensor responsive to the application of a voltage to the sensor, a means for measuring the internal resistance of the sensor, and a means for regulating at least one of the foregoing three means including a limiting electric current type oxygen concentration sensor, a means for applying a voltage to the sensor and a means for measuring a current flowing in the sensor, flowing the amount of the internal resistance of the sensor detected by the foregoing means for measuring the internal resistance of the sensor.

Equipment for detecting oxygen concentration

A limiting electric current type oxygen sensor comprising a first electrode of a gas-permeable film, a thin solid electrolyte film which is crystallized along one direction to decrease resistance and which has a thickness falling in the range between 0.1 .mu.m and 30 .mu.m, and a second electrode of a gas-permeable film sequentially formed on an electrically insulating substrate. This limiting electric current type oxygen sensor is also provided with a porous coating layer or a dense coating layer. The porous coating layer made of Al.sub.2 O.sub.3, SiO.sub.2, spinnel, SiC, Si.sub.3 N.sub.4 and etc., has a porosity of not more than 30% and a thickness of not less than 1 .mu.m, and serves as a gas diffusion flow rate-determining portion. The dense coating layer serves to control a gas permeation path such that either the first electrode or the substrate is used as the gas diffusion flow rate-determining portion.

Limiting electric current type oxygen sensor

An apparatus for detecting concentrations of a plurality of gas components has a single polarographic sensor capable of detecting an oxygen concentration and a composite concentration of oxygen gas, carbon dioxide gas and steam. A first voltage is applied to the polarographic sensor which then measures only the oxygen concentration, or a second voltage is applied to the sensor which then measures only the composite concentration of oxygen gas, carbon dioxide gas and steam. The first and second voltages are applied to the sensor in a time division manner. Upon application of first and second voltages in such a time division manner, corresponding currents flowing through the sensor are detected to obtain signals corresponding to the oxygen concentration and the composite concentration of oxygen gas, carbon dioxide gas and steam. The signal corresponding to the oxygen concentration is subtracted by an operational amplifier from the signal corresponding to the composite concentration of oxygen gas, carbon dioxide gas and steam, thereby obtaining a signal representing a composite concentration of carbon dioxide gas and steam.

Apparatus with polarographic sensor to detect concentrations of

The invention provides a limiting electric current type oxygen sensor with a microheater, having: an oxygen ionic conductor; an anode and a cathode respectively formed on two major surfaces of the oxygen ionic conductor; an insulating film which has a porosity of not less than 0.2 [%], an average pore diameter of not less than 140 [.ANG.], and a thickness between 0.2 [.mu.m] and 10 [.mu.m], and which is formed on one of the anode and the cathode so as to regulate a flow rate of oxygen gas and to provide electrical insulation; and the microheater formed on the insulating film. The oxygen ionic conductor is electrically insulated from the microheater through the insulating film. The invention also provides a limiting electric current type oxygen concentration detecting device having the limiting electric current type oxygen sensor and a constant temperature control circuit.

Limiting electric current type oxygen sensor with heater and limiting

An oxygen concentration detector provided with an oxygen concentration sensor further provided with an oxygen ionic conductor, a cathode placed on one surface of the oxygen ionic conductor, an anode placed on the other surface of the oxygen ionic conductor, and a layer convering the cathode for regulating the diffusion of oxygen gas toward the cathode. Temperature compensation is applied to the output of the detector which is inherently influenced by the temperature of the sensor. More specifically, an oxygen concentration detector is provided with the foregoing oxygen concentration sensor, and voltage or current is alternatively supplied to the sensor to measure a limiting current of the sensor and internal resistance of the sensor, and the current or the voltage produced by the foregoing application of voltage or current, and a temperature compensation is applied to the detected magnitude of limiting current according to the internal resistance of the sensor.

Growing community of inventors

Aichi, Japan

Keiichi Saji