Kabushiki Kaisha Toyota Chuo Kenkyusho

Toyota Jidosha Kabushiki Kaisha

Toyota Jidosha Kogyo Kabushiki Kaisha

Haruyoshi Kondo

Hideaki Takahashi

Takashi Takeuchi

Keiichi Saji

Kiyoharu Hayakawa

Masaharu Takeuchi

Toshihiro Ozasa

Naoki Katayama

Tadashi Inaba

Hideaki Muraki

Yasushi Yamada

Yasuhiro Otsuka

Toshinobu Furutani

Masayuki Matsui

Kazuhiro Kozuka

Mari Okazaki

Shigeo Suzuki

Kazunori Katoh

Kozo Satta

Kunio Fukuda

Koji Tsukada

An apparatus for analyzing air/fuel ratio sensor characteristics makes it possible to perform highly accurate analysis of the characteristics of an air/fuel ratio sensor to be measured. The apparatus comprises a sensor attachment means in which is mounted an air/fuel ratio sensor to be measured; a gas regulation means for supplying to the sensor attachment means a gas that is substantially equivalent to components of exhaust gases from an engine, or some components thereof; a control means for comparing an output from the air/fuel ratio sensor to be measured mounted in the sensor attachment means and an output from a reference stoichiometric air/fuel ratio sensor at the stoichiometric air/fuel ratio of the engine, to obtain a deviation therebetween and to obtain from a history of this deviation over time the composition and flow rate of gases to be controlled to compensate for this deviation, and issuing appropriate instructions to the gas regulation means; and an air/ratio measurement means for measuring a time average of the thus controlled air/fuel ratio.

Apparatus for analyzing air/fuel ratio sensor characteristics

A gas sensor using an ionic conductor has a thin-film gas detection portion on an alumina substrate. The gas detection portion comprises a zirconia ionic conductor layer, a pair of platinum electrodes provided with the ionic conductor layer interposed therebetween, and a pair of junction layers positioned between the ionic conductor layer and each electrode and formed in a state in which the substances of the ionic conductor layers and the electrodes are mixed therein. The gas sensor using an ionic conductor is formed by sequentially forming a first electrode, a first junction layer, an ionic conductor layer, a second junction layer, and a second electrode by a physical vapor deposition method on a substrate, wherein the first and second junction layers are formed to be in a state in which the substances of the ionic conductor layers and the electrodes are both present.

Gas sensor using ionic conductor

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

A gas sampling valve is provided with a small opening for gas sampling and a gas flow channel communicating therewith and is adapted to sample a gas in the gas flow passage by operating a valve for opening and closing the small opening, wherein at least one detector for detecting the concentration of oxygen or combustion gas is disposed in the gas flow passage, whereby the concentration of oxygen, an air excess ratio, the combustion efficiency, or the like can be measured without using a separate analyzer.

Gas sampling valve

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

An air-fuel ratio sensor comprising a limiting electric current type oxygen sensor portion, having a sequential stacking on a porous substrate of a first electrode with high gas permeability, a solid electrolytic thin film having a specific crystal orientation, a thickness of 0.1 to 30 .mu.m, and good crystallinity. The limiting electric current type oxygen sensor portion and second electrode with a high gas permeability, is arranged and connected in parallel with a resistive type oxygen sensor portion having interdigital electrodes formed on one or both major surfaces of an oxide semiconductor thin film, the resistance of which changes in accordance with oxygen partial pressure. The air-fuel ratio sensor also has a sensor heater formed on one surface of the porous substrate around the sensor portions. The overall structure of the sensor is coated with a porous ceramic coating to which a catalyst is added.

Air-fuel ratio sensor and apparatus 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

A thin film oxygen sensor with a microheater incorporates an oxide semiconductor and has an integral structure of a sensor portion and a heater portion, wherein a porous catalyst layer is formed on a surface of the sensor portion, and a thickness and an average pore diameter of the catalyst layer are determined such that a ratio of the thickness to the average pore diameter falls within a range of 50 to 3,000. The oxygen sensor has good reproducibility, high stability, and high sensitivity for changing a resistance in response to a change in an oxygen content in an atmosphere. The oxygen sensor can be manufactured at low cost and has a compact construction.

Thin film oxygen sensor with microheater

A temperature control apparatus detects an actual temperature of an object (e.g., sensor) to be controlled, and compares the actual temperature with a preset target temperature to obtain a difference therebetween, thereby keeping a heater temperature constant. The temperature control apparatus has a temperature rise rate limiter for controlling a temperature rise rate of the object to be controlled so as not to exceed a predetermined temperature rise rate. The object may thus not be damaged by thermal strain which results from a high temperature rise rate.

Temperature control apparatus

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

A sensor which has an insulating substrate on which is formed a heater layer for heating the sensor on a part thereof and which is operated above a predetermined temperature. The heater layer is made of a material which has a thickness of 0.2 .mu.m to 20 .mu.m and which is made of platinum, rhodium, palladium or a mixture thereof. The insulating substrate is made of alumina, quartz, spinel, magnesia, zirconia, or mixtures thereof. A heater protective layer having a thickness of 0.01 .mu.m to 500 .mu.m is made of materials based on alumina, silica, spinel, magnesia, zirconia or mixtures thereof.

Oxygen sensor with heater

An engine vibration sensor for detecting the engine vibration as an electric signal including a vibrator set to resonate at a specific frequency of vibration of an engine to which it is attached, the vibrator being composed of at least one piezoelectric plate and having a root and a vibrator element; means for increasing the cross-sectional area of the vibrator element to make the second moment of area of the root of the vibrator relatively larger than that of the vibrator element; a base to be connected to an engine body; and a clamp for retaining the root firmly between the clamp and the base. The clamp may be provided with a projection having a flat surface for retaining the root of the vibrator. This construction prevents a change in the effective length of the vibrator element, thereby stabilizing the characteristics of the resonant frequency of the vibrator.

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Aichi, Japan

Haruyoshi Kondo