Ngk Spark Plug Company, Limited

Yoshihiro Nakano

Takio Kojima

Satoshi Sugaya

Tetsuo Yamada

Shiro Kakimoto

Shinichi Nakagawa

Masahito Kida

Hitoshi Furuta

Yoshinori Hibino

Shinya Miyamoto

Chihiro Tomimatsu

Satoru Toda

Yuichi Koyama

Kimihiro Kohama

A gas sensor control apparatus () including a control section () which executes a first receiving process (STEP) for receiving a first detection result output from a mixed-potential-type ammonia detection section () for detecting ammonia contained in a gas under measurement and corresponding to the concentration of ammonia, a second receiving process (STEP) for receiving a second detection result output from an oxygen detection section () for detecting oxygen contained in the gas under measurement and corresponding to the concentration of oxygen, a first concentration calculation process (STEP) for calculating a first ammonia concentration of the gas under measurement based on the first detection result and the second detection result, and a pressure correction process (STEP) for correcting the first ammonia concentration based on pressure information obtained from an external device (), thereby obtaining a second ammonia concentration of the gas under measurement.

Gas sensor control apparatus, gas sensor apparatus, and internal combustion engine control apparatus

Disclosed is a gas sensor element having an electrode containing a first metal as a predominant component and a lead containing a second metal as a predominant component. The electrode and the lead are connected directly at a connection boundary thereof, or connected indirectly via a connection joint. The connection boundary or joint includes a component region where either one of the first and second metals lower in specific gravity than the other of the first and second metals is contained in an amount ranging between those in the electrode and the lead.

Gas sensor element, heater and gas sensor

Disclosed is an ammonia sensor element for detecting ammonia in a gas under measurement, including two mixed-potential-type ammonia detection cells that respectively include first and second ammonia detection electrodes. The first ammonia detection electrode has a metal composition containing Au as a predominant component. The second ammonia detection electrode has a metal composition containing Au as a predominant component. The metal compositions of the first and second ammonia detection electrodes are different from each other.

Ammonia sensor element and gas sensor

A sensor control apparatus supplies a constant current to an oxygen concentration detection cell when it judges that oxygen concentration is greater than 15% (the concentration of oxygen contained in a measurement chamber is high). The sensor control apparatus detects a first difference voltage generated in the oxygen concentration detection cell as a result of the flow of the constant current to the oxygen concentration detection cell after a predetermined first detection time following the supply of the constant current. The sensor control apparatus detects a second difference voltage generated in the oxygen concentration detection cell as a result of the flow of the constant current to the oxygen concentration detection cell after a second detection time, which is previously set to be longer than the first detection time, following the supply of the constant current.

Sensor control apparatus

A control apparatus mounted on a diesel vehicle including an oxidation catalyst, a selective reduction catalyst, and a gas sensor includes an activation determination section, a concentration computation section, and a deterioration determination section. The concentration computation section computes the concentration of flammable gas from a sensor output in a period during which the activation determination section determines that the oxidation catalyst is not in the activated state and computes the concentration of ammonia gas from the sensor output in a period during which the activation determination section determines that the oxidation catalyst is in the activated state. The deterioration determination section determines whether or not the oxidation catalyst has deteriorated, on the basis of the concentration of the flammable gas computed by the concentration computation section.

Control apparatus and gas detection method

A microcomputer calculates the concentration of ammonia contained in exhaust gas. The microcomputer repeatedly obtains from a first ammonia detection section a first ammonia electromotive force EMF1 whose value changes with both the concentrations of ammonia and a flammable gas contained in the exhaust gas. The microcomputer outputs, as ammonia concentration information at the present point in time, ammonia concentration information representing the ammonia concentration at the point 0.5 sec prior to the present point in time. The microcomputer sets a rich spike flag Fs when a first ammonia electromotive force change amount &#x394;EMF1 is smaller than a value obtained by multiplying a start determination value by &#x2212;1. When the rich spike flag Fs is set, the microcomputer sets the ammonia concentration information at the present point in time to the value of the ammonia concentration information at the point immediately before the rich spike flag Fs is set.

Concentration computation apparatus

A sensor controller includes a signal reception determination section and a use suspension section. The signal reception determination section determines whether or not the sensor controller has received a specific state signal that indicates a specific state in which exhaust gas may contain a specific gas that differs from ammonia and reacts with an ammonia sensor. When the signal reception determination section determines that the sensor controller has received the specific state signal, the use suspension section suspends at least temporarily use of a detection result detected by the ammonia sensor after the determination. Specifically, upon reception of the specific state signal, the sensor controller suspends at least temporarily the use of the detection result detected by the ammonia sensor after the reception of the specific state signal.

Sensor controller, internal combustion engine control system, and internal combustion engine controller

A microcomputer acquires first and second NHelectromotive forces from a first NHdetection section and a second NHdetection section, and computes a NHconcentration, which is the concentration of NHcontained in exhaust gas. The first and second NHdetection sections output the first and second NHelectromotive forces which vary with both the concentrations of NHand a flammable gas contained in the exhaust gas. The microcomputer acquires a second pumping current from an NOx detection section and computes an NOx concentration, which is the concentration of NOx contained in the exhaust gas. The NOx detection section outputs the second pumping current which varies with the concentration of NOx and the concentration of NH. The microcomputer determines whether or not the exhaust gas contains the flammable gas based on at least the first and second NHelectromotive forces and the second pumping current.

A concentration calculation apparatus, system and method which can compute a correction value for correcting an ammonia sensor output at a timing other than the time of fuel cut. A multi-gas sensor control apparatus () of a urea SCR system () begins recording (storing) a downstream NOx output value Sn and downstream ammonia output value Sa detected by a multi-gas sensor () (S) when the control apparatus determines that a DPF regeneration process is currently being performed (an affirmative determination in S). The apparatus () computes a downstream ammonia converted value Ca using a peak value of the downstream NOx output value Sn (S), and calculates a Gain correction coefficient based on a comparison of the downstream converted value Ca and the output value Sa (S). As a result, the Gain correction coefficient can be computed in accordance with the state of the ammonia detection section ().

Concentration calculation apparatus, concentration calculation system, and concentration calculation method

A multi-gas detection apparatus is configured such that electric power supplied from a power supply to a heater is controlled by pulse width modulation so as to control the temperature of a first solid electrolyte body. The multi-gas detection apparatus detects the concentration of ammonia by using a first ammonia detection section in which an electromotive force is generated between a first reference electrode and a first detection electrode in accordance with the concentration of ammonia in the exhaust gas. The multi-gas detection apparatus calculates the amount of a change (i.e., offset voltage) in the ammonia electromotive force caused by change in the output voltage of the power supply. The multi-gas detection apparatus corrects the ammonia electromotive force generated in the first ammonia detection section through use of the calculated change amount.

Gas detection apparatus

An ammonia detection section is disposed on an electrically insulating layer and includes a reference electrode, a solid electrolyte body for ammonia, and a detection electrode that are stacked in this order on the electrically insulating layer. In the ammonia detection section, a three-phase boundary is formed at the interface between the reference electrode and the solid electrolyte body for ammonia, and another three-phase boundary is formed at the interface between the detection electrode and the solid electrolyte body for ammonia. The concentration of ammonia in exhaust gas is thereby detected. The ammonia detection section includes a porous layer formed of an electrically insulating porous material and disposed between the insulating layer and the reference electrode.

Gas sensor

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 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

There is provided a gas sensor, including a gas sensing film formed of an oxide semiconductor material and a gas-permeable protection layer formed of oxide particles and arranged on the gas sensing film. The oxide particles of the protection layer have an average particle size of 500 nm or smaller.

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Komaki, Japan

Yoshihiro Nakano