Ngk Insulators, Inc.

Jun Usami

Akinobu Hattori

Toru Kodachi

Yuichi Sasaki

Motohiro Nishiwaki

Hiroshi Yamada

Takao Murase

Masao Kon

Takeshi Kajita

A gas analyzer includes a gas sensor, a drive section that pumps oxygen in first to third processing zones of the gas sensor, an operating section that operates a pumping current flowing in a third electro-chemical pump cell into a gas value to be measured, a display output section that displays a value operated by the operating section, or outputs the value as an electrical output to the external, and a heater drive section that heats the gas sensor to a predetermined temperature.

Gas analyzer and method of calibrating said gas analyzer

Method of compensating an output signal (YA) of a sensor exposed to an exhaust gas produced from an air-fuel mixture, the sensor including an electrochemical sensing cell which produces an electromotive force (Vs) corresponding an oxygen partial pressure in an internal space into which the exhaust gas diffuses with a predetermined resistance, and an oxygen pumping cell to which a pump current (Ip) is applied so as to control the oxygen partial pressure in the internal space such that the electromotive force is held at a constant value. The output signal corresponds to the pump current. The method includes the steps of: converting the analog output signal (YA) into a digital signal (YD) by an analog/digital converter; compensating the analog signal to a first sensitivity compensation, by adjusting an input signal range (FSR) of the analog/digital converter according to a coefficient (KA) which corresponds to a coefficient (KO.sub.2) of sensitivity of the pump current of the sensor to the O.sub.2 concentration of the exhaust gas.

Method of compensating output of air/fuel ratio sensor for variation in

A method of compensating an output of a sensor adapted to determine an air/fuel ratio of an air-fuel mixture, depending upon an oxygen concentration of an exhaust gas produced as a result of combustion of the air-fuel mixture, wherein the sensor includes a sensing element which has at least one electrochemical cell each having an oxygen-conductive solid electrolyte body and at least one pair of electrodes The method includes the steps of detecting at least one parameter selected from the group consisting of a temperature Tc of the sensing element, a pressure Pg of the exhaust gas, and a temperature Tg of the exhaust gas, and adjusting the output y.sub.0 of the sensor, based on the at least one parameter detected, to obtain a compensating output of the sensor.

Method of compensating output of A/F ratio sensor

A circuit is utilized for measuring a diffusion-limited current which flows through a diffusion-limited current element in proportion to an oxygen concentration which includes an output resistor connected in series with the element, a differential amplifier having a first input connected to a reference voltage supply source, a second input connected to ground, an output connected to the output resistor, and a feedback resistor connected between the first input of the differential amplifier and a point between the element and the output resistor, so that a bias voltage applied across the element is kept constant.

Circuit for measuring diffusion-limited current

A gas sensing element having a co-fired laminar structure including an electrochemical cell having a planar solid electrolyte body, and at least two electrodes disposed on the planar solid electrolyte body. The sensing element further includes two generally planar heaters which are formed on opposite sides of the electrochemical cell, respectively, and which are spaced apart from each other in a direction perpendicular to the planar solid electrolyte body, and a generally planar thermosensitive portion formed as an integral part of the laminar structure, for detecting a temperature of the laminar structure in the neighborhood of at least one of the electrodes of the electrochemical cell. The thermosensitive portion may partially define a diffusion chamber into which a measurement gas in an external space is introduced under a predetermined diffusion resistance, so that one of the electrodes is exposed to the introduced measurement gas.

Gas sensing element

An oxygen analyzing method for determining a positive or negative oxygen concentration of a measurement gas which changes between oxidizing and reducing atmospheres. The method uses a sensing element having an oxygen sensing cell wherein an electromotive force is induced between its measuring and reference electrodes according to the principle of an oxygen concentration cell. The atmosphere adjacent to the measuring electrode is controlled by controlling a pumping current to be applied to an oxygen pumping cell such that the electromotive force induced in the sensing cell is maintained at a predetermined level. A heater is provided to heat the sensing and pumping cells, to maintain their operating temperature within a range of 700.degree.-960.degree. C. The pumping current, or a signal to control the pumping current, is converted into an oxygen concentration signal whose level is held within one of a positive range and a negative range. The concentration signal represents the positive oxygen concentration of the oxidizing atmosphere, or the negative oxygen concentration of the reducing atmosphere.

Oxygen analyzing method and device

An oxygen concentration measuring device having a very small size detecting portion formed of unitary lamination of plate shaped members of an oxygen sensing element, a heater member and/or a temperature detecting member. The element comprises an oxygen concentration cell and a temperature compensation means for compensating a setting voltage to which an EMF generated by the concentration cell is compared. The detecting portion is provided with a printed contact terminal and housed in a probe equipped with a protecting tube. The printed contact terminal of the detecting portion is arranged to mate with a connecting element housed in a funnel-shaped contact member so as to allow easy mounting and detaching.

Oxygen concentration measuring device

An oxygen analyzer using an oxygen sensor by which the oxygen concentration of a measuring gas can be detected. The oxygen sensor includes an oxygen pump and an oxygen concentration cell. The detecting principle is to vary the reference voltage to be compared with an output electromotive force of the oxygen concentration cell by using a predetermined relationship between the electromotive force and the pumping current, thus eliminating the need of using a reference air of which oxygen concentration is compared as a reference.

Oxygen analyzer

A moisture (H.sub.2 O) measuring device for high temperature gas deriving the moisture content by taking a difference between measured values of oxygen concentration by an operational process. The one value of the an oxygen concentration is for oxygen content originally included in the measuring gas and the other value of the oxygen concentration is one additionally including oxygen content obtained by electrolysis of the moisture in the measuring gas. The two measured values are controlled by applying voltage for the oxygen pump.

Moisture measuring device for high temperature gas

The disclosed sensor probe for detecting a gas component concentration such as an oxygen concentration has a specific gas introducing tube arranged in a gas probe tube, whose one end is faced to a gas sensor portion, and possessing a gas inlet hole for introducing a gas to be measured into the gas sensor portion through the gas introducing tube and a gas outlet hole for discharging the gas. Under such a construction, since a sufficient amount of a gas to be measured can be supplied effectively into the gas sensor portion even if a velocity of the gas is low, it is possible to maintain a high measuring accuracy.

Sensor probe

A combustion control apparatus of a combustion furnace by an improved fuel and air complementary control system according to master control system is disclosed, which is provided with a regulating means connected to a master controller and adapted for detecting the amount of load change and for setting the length of an air damper control rod's length changing device to a preset standard value corresponding to the load, without controlling the oxygen concentration in the exhaust gas to a standard value, when the load change is increased to a value of not lower than the preset value. The combustion control apparatus can control stably the oxygen concentration in an exhaust gas to a low level even when a load is suddenly changed.

Growing community of inventors

Aichi, Japan

Jun Usami