Ngk Spark Plug Company, Limited

Shiro Kakimoto

Satoshi Sugaya

Wataru Matsutani

Yoshihiro Nakano

Hiroyuki Nishiyama

Tetsuo Yamada

Takafumi Oshima

Noboru Ishida

Takio Kojima

Hitoshi Yokoi

Ryuji Inoue

Tadashi Hattori

Koichi Imaeda

Atsushi Satsuma

Tetuo Yamada

A multi-gas sensor controlleris provided in an urea SCR systemwith an SCR catalyst, an aqueous urea injectorand a multi-gas sensor(ammonia sensor unit and NOx sensor unit). The multi-gas sensor controllerdetermines the concentration of ammonia in exhaust gas flowing out of the SCR catalyst, as a downstream ammonia concentration value, based on a detection result of the ammonia detection unit. The multi-gas sensor controllercontrols the aqueous urea injectorto supply urea to the SCR catalystin a fuel-cut state. Further, the multi-gas sensor controllercorrect the determined downstream ammonia concentration value based on a detection result of the NOx detection unit and an oxygen concentration of the exhaust gas after the supply of urea to the SCR catalyst with the control of the aqueous urea injectorby the controller

Concentration determination device and method

In a multi-gas sensor control apparatus, the concentrations of ammonia, NO, and NO contained in a gas under measurement are computed as a result of execution of gas concentration computation processing by a CPUof a microcomputer. In the gas concentration computation processing, depending on whether or not a correction permission condition is satisfied (S), the CPUswitches its operation between an operation of storing the latest corrected ammonia concentration as a value of 'NHconcentration (this time)' (S) and an operation of storing a value of 'NHconcentration (reference)' as a value of &#x201c;NHconcentration (this time)&#x201d; (S). The multi-gas sensor control apparatuscan suppress a decrease in the accuracy of detection of the ammonia concentration performed through use of a multi-gas sensor

Sensor control method and sensor control apparatus

A deterioration diagnosis device for an oxidation catalyst includes: a multi-gas sensor disposed in an exhaust passage downstream of an oxidation catalyst, the multi-gas sensor including a NOsensor unit and a NOsensor unit, the NOsensor unit directly detecting a NOconcentration in exhaust gas after passing through the oxidation catalyst, and the NOsensor unit directly detecting a NOconcentration in the exhaust gas; an NO concentration calculation unit configured to calculate an NO concentration in the exhaust gas after passing through the oxidation catalyst based on the NOconcentration and the NOconcentration; and a deterioration judgment unit configured to determine a deterioration degree of the oxidation catalyst from an evaluation value based on the NO concentration calculated by the NO concentration calculation unit.

Deterioration diagnosis device for oxidation catalyst

A multigas sensor (A) includes a multigas sensor element portion (A) having: a NOsensor portion (A) which detects the concentration of NO; and first and second ammonia sensor portions () having different ratios between a sensitivity of ammonia and a sensitivity of NO. The multigas sensor element portion has a plate-like shape which extends in the direction of the axis O. A temperature detecting portion () used for controlling the temperature of the NOsensor portion is disposed in the multigas sensor element portion. The first and second ammonia sensor portions are disposed on the outer surface of the NOsensor portion so that at least parts of the first and second ammonia sensor portions overlap with a first region () which is defined in the width direction by ends in the axial direction of the temperature detecting portion.

Multigas sensor and multigas sensor device

An ammonium gas sensor is provided. The ammonium gas sensor includes: a solid electrolyte layer having oxygen ion conductivity; a detection electrode formed on one surface of the solid electrolyte layer; a reference electrode that is a counter electrode of the detection electrode; a selective reaction layer covering the detection electrode; and a protection layer covering the selective reaction layer and made from a porous material; wherein the detection electrode includes a noble metal as a main component; the selective reaction layer includes oxide represented by AMOas a main component, where A is one or more kind(s) of metal, M is vanadium, tungsten, or molybdenum and x, y, z are atomic ratios; and the protection layer includes the oxide that is in an amount smaller than a content of the oxide included in the selective reaction layer.

Ammonium gas sensor

A method and apparatus for controlling a multi-gas sensor, including an NOsensor section and an ammonia sensor section. The NOsensor section includes a first pumping cell adapted to pump oxygen into or out of a gas under measurement introduced into a first measurement chamber, and a second pumping cell communicating with the first measurement chamber and configured such that a second pumping current Ipcorresponds to an NOconcentration of the gas under measurement. Oxygen concentration is calculated on the basis of a first pumping current flowing through the first pumping cell, and a corrected ammonia concentration is calculated on the basis of the oxygen concentration and the ammonia concentration output of the ammonia sensor section.

Method and apparatus for controlling multi-gas sensor

An ammonia gas sensor including a reference electrode () is formed on the back surface of a solid electrolyte member (), and a detection electrode () is formed on the front surface of the solid electrolyte member (). A detection lead () is provided on the front surface of the solid electrolyte member () such that the detection lead () is connected to the detection electrode (). An insulating layer (), () is provided between the detection lead () and the solid electrolyte member (), or on the detection lead ().

Ammonia gas sensor

In an ammonia sensor (), lead portions () and () are provided on an insulating substrate (); a pair of comb-shaped electrodes () and () are connected to the lead portions () and (), respectively; a sensitive layer () is provided on the comb-shaped electrodes () and (); and a protective layer () is provided on the sensitive layer (). Particularly, the sensitive layer () is formed of a gas-sensitive raw material predominantly containing ZrOand containing at least W in an amount of 2 to 40 wt. % as reduced to WO.

Growing community of inventors

Kasugai, Japan

Shiro Kakimoto