Toyota Jidosha Kabushiki Kaisha

Toyota Jidosha Kogyo Kabushiki Kaisha

Nippon Soken, Inc.

Takashi Kamo

Shigenori Sakurai

Toshinobu Furutani

Tadayoshi Ikai

Yoshio Torisu

Tsuneyuki Egami

Kazunori Yoshida

Tsutomu Saito

Mari Okazaki

Shirou Kimura

Ryuzou Hori

Mitosi Ando

Masahiko Sugiyama

Takaharu Saito

Shinya Ishii

An air/fuel ratio detector constructed of first and second elements positioned such that the gap between the closed end of the second element constructing the limit current type oxygen sensor and the end of a tubular heater is closed or such that the one of electrodes formed on the second element and located on the side contacting the exhaust gas is made of a material having no catalytic capability to purify the exhaust gas. As a result, the second element does not constitute a concentration cell so that the output characteristics obtainable are ideal from the rich to lean range of the air-fuel ratio.

Air/fuel ratio detector

A coating quality measuring device and a pattern plate including one reference pattern portion having a large pattern width and a plurality of strip pattern portions each having a smaller pattern width. The pattern plate is disposed opposite the coated surface. The pattern plate is reflected off the coated surface and a reflected image is formed on an image sensor. The image sensor successively outputs signals each corresponding to the light level of each strip pattern portion on a line extending in a width direction of each strip pattern portion of the reflected image. A computing device calculates an average signal level of the signals outputted by the image sensor, divides the difference between the average signal level and the signal level of each signal by the signal level of the reference pattern portion and calculates a square average value of the obtained division value to obtain a measure of the coating quality of the coated surface.

Coating quality measuring device and method

A coating quality measuring device has a pattern plate including one reference pattern portion having a larger pattern width and a plurality of strip pattern portions having different pattern widths which are smaller than that of the reference pattern portion and are decreased in order. The pattern plate is disposed opposite the coated surface. The pattern plate is reflected on the coated surface and a reflected image is formed on an image sensor. The image sensor successively outputs signals each corresponding to the lightness of each pattern portion on a line extending in a width direction of each pattern portion of the reflected image. A computing device calculates a difference between the peak value of the signal level of the output signal corresponding to each strip pattern portion in the reflected image and the signal level of the output signal corresponding to the ground portion, divides the calculated difference by the signal level of the output signal corresponding to the reference pattern portion and detects the pattern width of the strip pattern portion wherein the division value becomes not larger than a predetermined value, thereby to obtain the coating quality of the coated surface.

Coating quality measuring device

An air-fuel ratio detector and an air-fuel ratio measuring method for detecting an oxygen density in an exhaust gas emitted from the internal combustion engine of an automobile. The air-fuel ratio detector has a tubular body and a pair of partition members dividing the tubular body into a closed-end section and an open-end section. At least one of the partition members comprises a solid electrolyte permeable to oxygen ions. A pair of electrodes is mounted on opposite surfaces of the solid electrolyte and connected to a DC power supply, thus constituting an oxygen pump. Another pair of electrodes is mounted on one of the partition members and connected to a DC power supply, thus constituting a limited-current oxygen sensor. Oxygen is introduced into a space between the partition members at all times by the oxygen pump to maintain the gas, which has been supplied through a gas dispersion member into the space, lean.

Air-fuel ratio detector and method of measuring air-fuel ratio

A detector and a measuring method for detecting an air-fuel ratio in an internal combustion engine or the like. The detector has a tubular body having a closed end, a solid electrolyte permeable to oxygen ions which divides the interior of the tubular body into a closed-end section and an open-end section, and electrodes mounted on opposite surfaces of the solid electrolyte. One pair of the electrodes on the opposite surfaces of the solid electrolyte is connected to a circuit for detecting an electromotive force, thus constituting an oxygen sensor. The other electrode pair is connected to a DC power supply, thus constituting an oxygen pump. The oxygen sensor detects the quantity of oxygen in a gas supplied through a gas dispersion member. The direction of flow and magnitude of and electric current in the oxygen pump are controlled on the basis of an output from the oxygen sensor for enabling the gas to have a stoichiometric air-fuel ratio.

A method for detecting the oxygen concentration of a gas to be measured is disclosed using the limiting current type oxygen sensor. The method is characterized in that the relationship of an inclined straight line between the voltages applied to the oxygen sensor and the currents outputted therefrom is determined in such a manner that the inclined straight line may pass through the flat portions of the limiting current in the voltage-current characteristics curves at the different oxygen concentrations. The relationship between the outputted currents and the oxygen concentrations at the flat portion is such that when a given magnitude of voltage is applied to the oxygen sensor to cause it to output a current, a voltage which corresponds to this current at the inclined straight line is determined. The voltage thus determined is applied to the oxygen sensor to cause it to output a current. The oxygen concentration is determined from the current thus outputted with reference to the outputted current-oxygen concentration conversion straight line. There is also disclosed a method for controlling the air-to-fuel ratio of a gas from an engine using the above voltage-current characteristic curves, inclined straight line and outputted current-oxygen concentration.

Method for detecting an oxygen concentration and a method for

An oxygen sensor element with a ceramic heater, having a cylindrical element body formed of an oxygen ion permeable solid electrolyte with one end closed, inner and outer electrodes formed on the inner and outer surfaces of the element body, and an electrode protective layer covering at least one of the inner and outer electrodes, the ceramic heater including a bar-like ceramic core member, a ceramic covering layer which covers the outer surface of the ceramic core member and a heating member disposed in the interface between the core member and the covering layer.

Oxygen sensor element with a ceramic heater and a method for

An oxygen sensor element having an oxygen ion-permeable solid electrolyte having a tabular or columnar shape and electrode layers formed on the solid electrolyte. At least one of the electrode layers is composed of a fired body having a uniform structure consisting of 100 weight parts of a metal and 0.1 to 10 weight parts of a glass which consists of the following materials in molar amounts: SiO.sub.2, 62-75%; ZrO.sub.2, 7-11%; R.sub.2 O, 13-23%; R'O, 1-10%; Al.sub.2 O.sub.3, 0-4%; B.sub.2 O.sub.3, 0-6%; Fe.sub.2 O.sub.3, 0-5%; CaF.sub.2, 0-2%; and TiO.sub.2, 0-4%; wherein R.sub.2 O is Na.sub.2 O which is substantially pure or is substituted by Li.sub.2 O within 2 mole percent thereof, and R'O is an oxide selected from the group consisting of the alkaline-earth metal oxides, ZnO and MnO. Disclosed also is a method of producing the oxygen sensor element.

Oxygen sensor element

A leanness sensor has a sensor element made of an oxygen-permeable solid electrolyte and having a cylindrical form or a form like a vessel closed at one end thereof. The sensor element is provided with metallic electrodes formed on the inner and outer surfaces thereof. An inner metallic member and an outer metallic member are mounted on the sensor element and electrically connected to the metallic electrodes. The sensor element is fixed to the inner side of the end portion of a cylindrical insulating tube.

Leanness sensor

A lean sensor for sensing oxygen concentration in exhaust emissions, including a sensor element consisting of a tabular solid electrolyte having opposed sides provided with electrodes with at least one surface thereof coated with a porous coating layer, an element fixing plate having an element fitting hole to which the element is fitted, and a pair of heat-resistant insulating support plates having opposing windows and clamping therebetween the element fixing plate together with the sensor element disposed in the windows. In this way, it is possible precisely to locate the element in relation to the plate and to improve the bonding strength and reliability while reducing the size of the sensor as a whole.

Lean sensor

Metallized layers are formed respectively on the surfaces to be joined of the ceramic members by performing metallized treatment on the surfaces, and then, these metallized layers are pressed against each other, and under pressure are diffusion-bonded at high temperature. A metal foil which can form a solid solution with the metallized layers can be interposed between the metallized layers before diffusion-bonding. This method can be used to manufacture an oxygen sensor element.

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Toyota, Japan

Takashi Kamo