Toyota Jidosha Kabushiki Kaisha

Yamaha Hatsudoki Kabushiki Kaisha

Takefumi Uchida

Harufumi Muto

Yoshihisa Oda

Isao Nakajima

Toshihiro Kato

Takeo Kondo

Hitoshi Tanaka

Yutaka Iwami

Hideyuki Ishiyama

An apparatus for detecting an abnormal air-fuel ratio variation, includes an abnormality detecting unit that detects an abnormal variation in each of a plurality of fuel injection valves on the basis of an injection ratio between the plurality of fuel injection valves, a fluctuation in the output before the injection ratio is changed and the fluctuation in the output after the injection ratio is changed; and a setting unit that corrects the abnormality determination threshold for each of the plurality of fuel injection valves on the basis of the injection ratio.

Apparatus and method for detecting abnormal air-fuel ratio variation

In an abnormality detection apparatus and an abnormality detection method for a construction in which each of cylinders is provided with a plurality of fuel injection valves, if it is discerned that a cause of the inter-cylinder variation abnormality exists in one of the fuel injection valves, an air/fuel ratio fluctuation parameter as an index value that represents the degree of the abnormality is calculated by normalizing the air/fuel ratio fluctuation parameter regarding that fuel injection valve on the basis of the injection proportion used when the parameter is measured.

Air/fuel ratio variation abnormality detection apparatus, and abnormality detection method

An internal combustion engine is provided in which fuel pressure is changed and fuel injection is controlled in accordance with engine operating conditions. The internal combustion engine comprises a cylinder, a direct injection injector, a detection unit, and a control unit. The control unit includes two maps describing two factors of a fuel injection characteristic coefficient and an invalid injection period with respect to the fuel pressure of the direct injection injector. A first calculating section calculates a required fuel injection quantity. A second calculating section calculates a required fuel injection period in accordance with the required fuel injection quantity and the two factors of the fuel injection characteristic coefficient and the invalid injection period with respect to the fuel pressure. A controlling section controls the fuel injection such that the fuel is injected for the required fuel injection period.

Internal combustion engine

An electronic control unit corrects ignition timing according to changes in an internal EGR amount accompanying actuation of a variable valve actuation mechanism used in an internal combustion engine. The electronic control unit computes a base correction amount AVVTb based on an engine speed NE and an engine load ratio KL. The control unit multiplies the base correction amount AVVTb by the ratio of a square number of an actual valve overlap amount realOL to a square number of a target valve overlap amount tOL, thereby computing a VVT correction amount AVVT of ignition timing. As result, the engine is easily and properly controlled based on the relationship between the state of the variable valve actuation mechanism and changes in the internal EGR amount.

Apparatus for controlling internal combustion engine

An electronic control unit of an internal combustion engine computes a remaining combusted gas amount M, which exists in a cylinder immediately before an intake valve is opened, based on an intake pipe pressure Pm, an engine speed NE, and an intake valve opening timing T. At the same time, the control unit computes a backflow combusted gas amount M, which is the amount of combusted gas that flows back into the cylinder from an exhaust pipe after the intake valve is opened, based on the intake pipe pressure Pm, the engine speed NE and a valve overlap amount OL. The control unit computes the sum of the remaining combusted gas amount Mand the backflow combusted gas amount M, and sets the sum as an estimated internal EGR amount M. As a result, the internal EGR amount is readily and accurately estimated.

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Toyota, Japan

Takefumi Uchida