Toyota Jidosha Kabushiki Kaisha

Denso Corporation

Takashi Yui

Kota Hayashi

Noboru Takagi

Tokiji Ito

Hirohiko Yamada

Kiyoo Hirose

Keizo Hiraku

An internal combustion engine includes a variable mechanism that changes a working angle of an intake valve. A controller diagnoses whether there is an abnormality that an intake air amount reduces during idle operation. The controller changes an abnormality determination threshold for diagnosing an abnormality on the basis of a mode in which the working angle is changed by the variable mechanism.

Diagnostic system and diagnostic method for internal combustion engine

A detecting apparatus that detects an abnormality of imbalance of air-fuel ratios among cylinders of a multi-cylinder internal combustion engine, which is equipped with a variable working angle mechanism of an intake valve, the detecting apparatus includes an abnormality detection portion that detects a parameter regarding rotational fluctuations of each of the cylinders and detects whether or not there is an abnormality of imbalance of air-fuel ratios among the cylinders. The abnormality detection portion refrains from determining that the air-fuel ratios are normal when the working angle at the time of detection of the parameter is within a predetermined large working angle range, and determines that the air-fuel ratios are normal when the working angle at the time of detection of the parameter is within a predetermined small working angle range that is on a small working angle side with respect to the large working angle range.

Apparatus and method for detecting abnormality of imbalance of air-fuel ratios among cylinders

An controller detects a change in a load generation state of an accessory device that generates a load on the internal combustion engine during operation, and the controller in turn controls a variable valve mechanism to change at least one of an operation angle and a valve lift of an intake valve of the internal combustion engine, as well as changing an amount of an intake air drawn into the internal combustion engine, in response to the detected change in the load generation state of the accessory device.

Idling speed control system and method

Growing community of inventors

Miyoshi, Japan

Takashi Yui