Gas sensor

Patent metadata

Field	Value
Publication number	US-10088446-B2
Application number	US-201515315738-A
Country	US
Kind code	B2
Filing date	Jun 4, 2015
Priority date	Jun 4, 2014
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

A gas sensor device is equipped with a pump cell and a sensor cell. The pump cell works to regulate the concentration of oxygen in a measurement gas space. The sensor cell works to measure an oxygen ion current flowing between a sensor electrode and a reference electrode. The gas sensor device is designed to subtract the oxygen ion current value I2, as measured by the sensor cell a given period of time after spraying of fuel into the internal combustion engine is interrupted, from the oxygen ion current value I1, as measured by the sensor cell when the fuel is being sprayed into the internal combustion engine, to derive the concentration of a given gas component based on the corrected oxygen ion current value I. This results in improved accuracy in determining the concentration of the given gas component.

First claim

What is claimed is:

1. A method of measuring a concentration of a given gas component in exhaust gas flowing in an exhaust pipe of an internal combustion engine using a gas sensor device which is arranged in the exhaust pipe of the internal combustion engine, the gas sensor device comprising:
a solid electrolyte body which has oxygen ion conductivity;
a measurement gas space which is formed on one of surfaces of the solid electrolyte body and into which the exhaust gas is introduced as a measurement gas through a diffusion resistor;
a reference gas space which is formed on the other surface of the solid electrolyte body and into which a reference gas is introduced;
a pump cell which has a pump electrode disposed on a surface of the solid electrolyte body which faces the measurement gas space, the pump cell being designed so that voltage is applied between the pump electrode and a reference electrode disposed on a surface of the solid electrolyte body which faces the reference gas space to regulate a concentration of oxygen in the measurement gas space; and
a sensor cell which has a sensor electrode disposed on the surface of the solid electrolyte body which faces the measurement gas space downstream of the pump electrode in a flow direction of the measurement gas, the sensor cell working to measure an oxygen ion current flowing between the sensor electrode and the reference electrode,
wherein an oxygen ion current value, as measured by the sensor cell a given period of time after spraying of fuel into the internal combustion engine is interrupted, is subtracted from an oxygen ion current value, as measured by the sensor cell when the fuel is being sprayed into the internal combustion engine to derive the concentration of the given gas component.

2. The method as set forth in claim 1 , wherein the measurement gas space includes a first gas space in which the pump cell is disposed and a second gas space in which the sensor cell is disposed, and in that the first gas space and the second gas space communicate with each other and are separate from each other by a barrier wall which decreases a spatial cross section in the flow direction of the measurement gas or a gas permeable porous body.

3. The method as set forth in claim 2 , wherein in the second gas space, an auxiliary pump cell which works to further regulate a concentration of oxygen in the measurement gas whose concentration of oxygen has already been regulated by the pump cell, and in that the auxiliary pump cell has an auxiliary pump cell disposed on the surface of the solid electrolyte body which faces the measurement gas space, voltage being applied between the auxiliary pump electrode and the reference electrode to regulate the concentration of oxygen in the second gas space.

Assignees

• Denso Corp

Inventors

• Araki Takashi
• Mizutani Keigo

Classifications

• G01N27/4072

  characterized by the diffusion barrier · CPC title

• G01N27/41 Primary

  Oxygen pumping cells · CPC title

• G01N27/416

  Systems (G01N27/27 takes precedence) · CPC title

• G01M15/104

  using oxygen or lambda-sensors (testing catalytic converters F01N3/18, F01N11/007) · CPC title

• G01N27/419 Primary

  Measuring voltages or currents with a combination of oxygen pumping cells and oxygen concentration cells · CPC title