Control device for internal combustion engine

Patent metadata

Field	Value
Publication number	US-10408149-B2
Application number	US-201314441681-A
Country	US
Kind code	B2
Filing date	May 24, 2013
Priority date	Feb 18, 2013
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

A sensor for detecting oxygen concentration in exhaust gas or an air-fuel ratio provided with a solid electrolyte body, an exhaust gas side electrode being disposed on one side of the solid electrolyte body and being in contact with the exhaust gas, an atmosphere side electrode being disposed on the other side of the solid electrolyte body and being in contact with the atmosphere, and an electric circuit applying a reference voltage between these electrodes is arranged in an engine exhaust passage. The sensor for detecting the oxygen concentration in the exhaust gas or the air-fuel ratio has a characteristic in which an output current continues to increase without having a limiting current region when the voltage applied between the electrodes is increased while the air-fuel ratio is constant. The air-fuel ratio is controlled based on the output current of the sensor for detecting the oxygen concentration in the exhaust gas or the air-fuel ratio.

First claim

What is claimed is:

1. A control device for an internal combustion engine, the control device comprising:
a sensor configured to detect an oxygen concentration in an exhaust gas or an air-fuel ratio, the sensor being arranged in an exhaust passage of the internal combustion engine, the sensor including a solid electrolyte body, an exhaust gas side electrode, a reference gas side electrode, and an electric circuit, the exhaust gas side electrode being disposed on one side of the solid electrolyte body and being in contact with the exhaust gas, the reference gas side electrode being disposed on the other side of the solid electrolyte body and being in contact with reference gas, the electric circuit applying a reference voltage between the exhaust gas side electrode and the reference gas side electrode, and the sensor is provided with no diffusion rate controlling layer and a coating layer having a porosity such that said sensor has a characteristic in which an output current continues to increase without having a limiting current region when the voltage applied between the exhaust gas side electrode and the reference gas side electrode is increased while the air-fuel ratio is constant; and
an electronic control unit configured to control the air-fuel ratio based on the output current of the sensor,
wherein the sensor has a characteristic in which the output current increases as the air-fuel ratio increases,
wherein the electronic control unit is configured to determine that the air-fuel ratio is lower than a reference air-fuel ratio when the output current is less than a reference current corresponding to the reference air-fuel ratio,
wherein the electronic control unit is configured to determine that the air-fuel ratio is higher than the reference air-fuel ratio when the output current is greater than the reference current, wherein the reference current corresponds to the reference air-fuel ratio,
wherein the electronic control unit is configured to control the air-fuel ratio based on the determination result,
wherein the reference air-fuel ratio is equal to a theoretical air-fuel ratio, and
wherein the reference voltage is set such that when applying the reference voltage between the exhaust gas side electrode and the reference gas side electrode the output current of the sensor is equal to the reference current and is equal to zero.

2. The control device according to claim 1 ,
wherein the electronic control unit is configured to set the reference current based on the temperature of the sensor.

3. The control device according to claim 2 ,
wherein the electronic control unit is configured to increase the reference current as the temperature of the sensor increases.

4. The control device according to claim 1 ,
wherein the reference voltage is set such that the reference current has a positive value.

5. The control device according to claim 1 ,
wherein the reference gas comprises an atmospheric gas.

Assignees

• Aoki Keiichiro
• Hayashita Go
• Toyota Motor Co Ltd

Inventors

• Aoki Keiichiro
• Hayashita Go

Classifications

• G01N27/4072

  characterized by the diffusion barrier · CPC title

• G01N27/4065

  Circuit arrangements specially adapted therefor · CPC title

• F02D41/1456 Primary

  with sensor output signal being linear or quasi-linear with the concentration of oxygen · CPC title

• F02D41/1454 Primary

  the characteristics being an oxygen content or concentration or the air-fuel ratio · CPC title

• G01N27/409

  Oxygen concentration cells · CPC title