Toyota Jidosha Kabushiki Kaisha

Denso Corporation

Daisuke Kojima

Masumi Kinugawa

Hiroshi Haraguchi

Tomoo Kawase

Yasuhiro Kariya

Tatsumasa Sugiyama

Kiyonori Sekiguti

A gas concentration detector prevents deviation in output due to a difference in oxygen reactivity between electrode materials to accurately detect a specific gas component in a gas to be measured, such as NOx in an exhaust gas. A sensor element in an NOx sensor has a pump cell in a first chamber and a sensor cell for decomposing NOx and any remaining oxygen and a monitor cell for decomposing only remaining oxygen in a second chamber. An NOx concentration is detected based on a difference in current output between the sensor cell and the monitor cell. Since the sensor cell and the monitor cell have different oxygen reactivities, an output of the monitor cell is smoothed through a band-pass filter or the like so that output responses of the sensor cell and the monitor cell are made to substantially match each other, thereby eliminating any deviation in output.

Gas concentration detector

If the amount of fuel added to exhaust gas becomes excessive as a result of an abnormality of an addition agent supply unit (), the air-fuel ratio of exhaust as decreases. If an exhaust gas air-fuel ratio obtained from a value output from an A/F sensor () remains equal to or smaller than a predetermined value for a predetermined period, an ECU () determines that an addition agent supply unit () is abnormal. Upon detection of an abnormality of the addition agent supply unit (), the ECU () incrteases an amount of EGR gas recirculated to the intake side by an EGR unit (), reduces an amount of fuel injection from injectors (), and restricts an operational state of an engine body () to a low-speed/low-load state. Also, the ECU () turns a warning lamp () on, warns a driver of the abnormality of the addition agent supply unit (), and makes it possible to pull a vehicle over safely.

Control device and control method for internal combustion engine

Growing community of inventors

Nagoya, Japan

Daisuke Kojima