O2 sensor, apparatus for and method of controlling air-fuel ratio, and recording medium storing air-fuel ratio control program
AssigneeHonda Giken Kogyo Kabushiki Kaisha
InventorsYuji Yasui, Yoshihisa Iwaki
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Abstract
A system controls the air-fuel ratio in an exhaust gas supplied from an internal combustion engine to a catalytic converter in order to keep an output voltage Vout of an O2 sensor disposed downstream of the catalytic converter at a predetermined target value Vop. In the system, the temperature of an active element of the O2 sensor is controlled at a predetermined temperature such that the output voltage of the O2 sensor at an inflection point of output characteristics thereof is substantially the same as the target value Vop.
Claims18
An O2 sensor in a system for controlling an air-fuel ratio in an exhaust gas supplied from an internal combustion engine to a catalytic converter disposed in an exhaust passage of the internal combustion engine for keeping an output voltage of the O2 sensor at a predetermined target value to achieve a predetermined exhaust gas purifying capability of the catalytic converter, said O2 sensor being disposed in the exhaust passage downstream of said catalytic converter for generating an output voltage having a level depending on the concentration of oxygen in the exhaust gas, said output voltage changing with respect to the air-fuel ratio in the exhaust gas which is represented by the concentration of oxygen, at a gradient which switches from a large gradient to a small gradient via an inflection point as said air-fuel ratio turns richer,
- said O2 sensor having such output characteristics that the output voltage thereof at said inflection point is substantially the same as said target value.
An apparatus for controlling an air-fuel ratio in an exhaust gas supplied from an internal combustion engine to a catalytic converter disposed in an exhaust passage of the internal combustion engine for keeping an output voltage of an O2 sensor at a predetermined target value to achieve a predetermined exhaust gas purifying capability of the catalytic converter, said O2 sensor being disposed in the exhaust passage downstream of said catalytic converter for generating an output voltage having a level depending on the concentration of oxygen in the exhaust gas, said apparatus comprising:
- sensor temperature control means for controlling the temperature of an active element of the O2 sensor so as to be kept at a predetermined temperature.
A method of controlling an air-fuel ratio in an exhaust gas supplied from an internal combustion engine to a catalytic converter disposed in an exhaust passage of the internal combustion engine for keeping an output voltage of an O2 sensor at a predetermined target value to achieve a predetermined exhaust gas purifying capability of the catalytic converter, said O2 sensor being disposed in the exhaust passage downstream of said catalytic converter for generating an output voltage having a level depending on the concentration of oxygen in the exhaust gas, said method comprising the step of:
- controlling the temperature of an active element of the O2 sensor so as to be kept at a predetermined temperature when the air-fuel ratio in the exhaust gas is controlled.
A recording medium readable by a computer and storing an air-fuel ratio control program for enabling said computer to perform, in a system having an O2 sensor disposed in an exhaust passage of an internal combustion engine downstream of a catalytic converter disposed in said exhaust passage, for generating an output voltage having a level depending on the concentration of oxygen in an exhaust gas supplied from said internal combustion engine through said exhaust passage to said catalytic converter, a process of controlling an air-fuel ratio in the exhaust gas for keeping an output voltage of the O2 sensor at a predetermined target value to achieve a predetermined exhaust gas purifying capability of the catalytic converter, said air-fuel ratio control program comprising a program for enabling said computer to perform a process of controlling the temperature of an active element of the O2 sensor so as to be kept at a predetermined temperature when the air-fuel ratio in the exhaust gas is controlled.
Dependencies are inferred from the claim text.