Control device of internal combustion engine

Patent metadata

Field	Value
Publication number	US-2016003181-A1
Application number	US-201414769956-A
Country	US
Kind code	A1
Filing date	Jan 21, 2014
Priority date	Feb 25, 2013
Publication date	Jan 7, 2016
Grant date	—

Abstract

A control device of an internal combustion engine according to the present invention executes air-fuel ratio control based on an output of an air-fuel ratio sensor provided at an upstream side of a catalyst, with correction based on an output of an oxygen sensor at a downstream side of the catalyst. When it is determined that a degree of an output tendency in a predetermined lean region is not less than a predetermined lean degree, and that a degree of an output tendency in a predetermined rich region is less than a predetermined rich degree based on lean tendency and rich tendency values representing output tendencies of the oxygen sensor, a limit is set to the correction in a direction to more suppress enriching of an air-fuel ratio as a degree is larger in which the output of the oxygen sensor is shifted to a lean side.

First claim

1 . A control device of an internal combustion engine, comprising:
an air-fuel ratio control unit configured to execute air-fuel ratio control based on an output of an air-fuel ratio sensor provided at an upstream side of an exhaust purification catalyst of an exhaust passage, the air-fuel ratio control unit executing correction to the air-fuel ratio control by a correction amount set based on an output of an oxygen sensor provided at a downstream side of the exhaust purification catalyst; an output tendency value calculation unit configured to calculate a value that represents an output tendency of the oxygen sensor based on the output of the oxygen sensor, the output tendency value calculation unit calculating a lean tendency value that represents a lean output tendency in a predetermined lean region closer to a lean side than a theoretical air-fuel ratio and a rich tendency value that represents a rich output tendency in a predetermined rich region closer to a rich side than the theoretical air-fuel ratio in a predetermined time; a determination unit configured to determine whether or not a degree of the lean output tendency in the predetermined lean region is not less than a predetermined lean degree based on the lean tendency value calculated by the output tendency value calculation unit, and determine whether or not a degree of the rich output tendency in the predetermined rich region is less than a predetermined rich degree based on the rich tendency value calculated by the output tendency value calculation unit; and a limit setting unit configured to set a limit to the correction to the air-fuel ratio control in a direction to more suppress enriching of an air-fuel ratio as a degree is larger in which the output of the oxygen sensor is shifted to the lean side, when it is determined by the determination unit that the degree of the lean output tendency in the predetermined lean region is not less than the predetermined lean degree, and that the degree of the rich output tendency in the predetermined rich region is less than the predetermined rich degree.

2 . The control device of the internal combustion engine according to claim 1 , wherein the limit setting unit uses the lean tendency value calculated by the output tendency value calculation unit as a value representing the degree in which the output of the oxygen sensor is shifted to the lean side, and sets the limit to the correction based on the lean tendency value.

3 . The control device of the internal combustion engine according to claim 1 , further comprising a temperature detection unit configured to detect an element temperature of the oxygen sensor, wherein
the output tendency value calculation unit calculates at least the rich tendency value based on the output of the oxygen sensor when the element temperature of the oxygen sensor detected by the temperature detection unit is not more than a predetermined temperature having a correspondence relation with a lean-side boundary value of the predetermined rich region.

4 . The control device of the internal combustion engine according to claim 1 , further comprising:
a temperature detection unit configured to detect an element temperature of the oxygen sensor; and a rich region setting unit configured to set a lean-side boundary value of the predetermined rich region based on the element temperature of the oxygen sensor detected by the temperature detection unit.

Assignees

• Okada Masahide
• Hakariya Masashi
• Matsuda Yoshifumi
• Oda Yoshihisa
• Tsuji Hiroaki
• Ito Tokiji
• Nakajima Isao
• Kato Toshihiro
• Yoshikawa Yuya
• Toyota Motor Co Ltd

Inventors

• Okada Masahide
• Hakariya Masashi
• Matsuda Yoshifumi
• Oda Yoshihisa
• Tsuji Hiroaki
• Ito Tokiji
• Nakajima Isao
• Kato Toshihiro
• Yoshikawa Yuya

Classifications

• Y02T10/40

  Engine management systems · CPC title

• F02D41/222

  relating to the failure of sensors or parameter detection devices · CPC title

• F02D41/1475

  Regulating the air fuel ratio at a value other than stoichiometry · CPC title

• F02D41/1456

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

• F02D41/1455

  with sensor resistivity varying with oxygen concentration (F02D41/1456 takes precedence) · CPC title