Ngk Spark Plug Company, Limited

Tatsuo Okumura

Takafumi Oshima

Noboru Ishida

Yoshikuni Sato

Masashi Ando

Norihiko Nadanami

Satoshi Sugaya

Yasuhisa Kuzuya

Takaki Otsuka

Takaki Ootuka

A method for detecting the concentration of a specific component in gas discharged from an internal combustion engine, which includes detecting the concentration of the specific component under certain driving conditions to determine a zero point, which indicates a zero concentration of the specific component, of the detection output; calibrating the detection output of the gas sensor based on the determined zero point; and detecting the concentration of the specific component in exhaust gas based on the calibrated detection output.

Methods and apparatus for measuring NOx gas concentration, for detecting exhaust gas concentration and for calibrating and controlling gas sensor

Method and apparatus for correcting a gas sensor response for moisture in exhaust gas

Method and sensor for measuring accurate measurement of NOx concentration in an exhaust gas containing O ,H O, CO and NOx and a NOx gas concentration sensor. A first oxygen pump cell sufficiently pumps out oxygen in a measurement gas such as not to decompose NOx. A pair of electrodes is provided on an inner side and an outer side of a second measurement chamber into which the gas is introduced from a first measurement chamber via a diffusion resistance. A voltage is impressed across the paired electrodes for decomposing NOx in the second measurement chamber to dissociate oxygen which causes the current to flow in a second oxygen ion pump cell. The NOx gas concentration is measured for this current. The voltage impressed across the paired electrodes of the second oxygen ion pump cell is set so as not to dissociate H O and CO present in the second measurement chamber.

Method and apparatus for measuring NOx gas concentration

A nitrogen oxide concentration detector has a first measurement chamber into which is introduced a measurement gas via a first diffusion resistance an oxygen concentration detection electrode for measuring the oxygen concentration in the measurement gas in said first measurement chamber a first oxygen ion pump cell for pumping out oxygen in the measurement gas from said first measurement chamber based on the potential of said oxygen concentration detection electrode a second measurement chamber into which the gas is introduced from said first measurement chamber via a second diffusion resistance and a second oxygen ion pump cell having a pair of electrodes across which a voltage is applied to decompose NOx in the second measurement chamber to pump out dissociated oxygen to cause a circuit Ip corresponding to the NOx concentration to flow in the second oxygen ion pump cell Variation of NOx concentration is a function of variation of Ip The concentration obtained based on the Ip is corrected responsive to the oxygen concentration in the measurement gas. Particularly, a coefficient of the variation of the Ip gain, in said function is corrected responsive to the oxygen concentration in the measurement gas.

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Hashima-gun, Japan

Tatsuo Okumura