| US 7,474,956 B2 | ||
| Air-fuel ratio control system of internal combustion engine | ||
| Norihisa Nakagawa, Numazu (Japan); Takahiko Fujiwara, Susono (Japan); Taiga Hagimoto, Susono (Japan); Junichi Kako, Susono (Japan); Naoto Kato, Susono (Japan); and Shuntaro Okazaki, Susono (Japan) | ||
| Assigned to Toyota Jidosha Kabushiki Kaisha, Toyota (Japan) | ||
| Appl. No. 11/885,266 PCT Filed Sep. 13, 2006, PCT No. PCT/JP2006/018544 § 371(c)(1), (2), (4) Date Aug. 29, 2007, PCT Pub. No. WO2007/032534, PCT Pub. Date Mar. 22, 2007. |
||
| Claims priority of application No. 2005-268295 (JP), filed on Sep. 15, 2005; and application No. 2006-035479 (JP), filed on Feb. 13, 2006. | ||
| Prior Publication US 2008/0147297 A1, Jun. 19, 2008 | ||
| Int. Cl. G06F 19/00 (2006.01); F02D 41/14 (2006.01); F01N 3/10 (2006.01) | ||
| U.S. Cl. 701—109 [60/276; 60/285] | 25 Claims |
| 1. An air-fuel ratio control system of an internal combustion engine comprising:
an exhaust purification catalyst having an oxygen storage capacity arranged in an exhaust passage of the internal combustion
engine, storing oxygen in the exhaust when a concentration of oxygen in inflowing exhaust is in excess, and releasing stored
oxygen when the concentration of oxygen in the exhaust is insufficient,
an intake air amount detecting means for detecting an intake air amount of said internal combustion engine,
a linear air-fuel ratio sensor arranged at an upstream side of said exhaust purification catalyst and having an output characteristic
substantially proportional to an air-fuel ratio of the exhaust,
an O2 sensor arranged at a downstream side of said exhaust purification catalyst and sensing if an air-fuel ratio of the exhaust
is rich or lean,
a target air-fuel ratio controlling means for performing feedback control of a target air-fuel ratio of exhaust flowing into
said exhaust purification catalyst based on detection information from said intake air amount detecting means and said O2 sensor, and
a fuel injection amount controlling means for performing feedback control of the fuel injection amount based on output information
of said linear air-fuel ratio sensor so as to control said air-fuel ratio of the exhaust flowing into the exhaust purification
catalyst to said target air-fuel ratio,
said air-fuel ratio control system of an internal combustion engine characterized in that said target air-fuel ratio controlling
means performs feedback control of said target air-fuel ratio so that even when said intake air amount changes, a correction
amount per unit time of an oxygen storage amount of said exhaust purification catalyst is made constant.
|