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AssigneeToyota Jidosha Kabushiki Kaisha
InventorsKenya Maruyama, Takahiro Nishigaki, Toshitake Sasaki
Estimating the term…
When an engine is in a predetermined steady operating state, a gradient accumulation average value ΔAulsa corresponding to the amount of change in the air-fuel ratio AF, detected by an air-fuel ratio sensor, over the period of time from when an upper peak is reached, at which the direction of change in the air-fuel ratio AF is inverted to when a lower peak is reached, at which the subsequent inversion of the direction occurs, is calculated (S100 to S160) and, when the calculated gradient accumulation average value ΔAulsa is greater than a predetermined threshold value ΔAref1 that is determined in advance as an upper limit (absolute value) of the range, in which it may be determined that the air-fuel ratio is even between the cylinders of the engine (S165 to S175), it is determined that the engine is in an air-fuel ratio imbalance state, in which there is an imbalance in air-fuel ratio between the cylinders of the engine.
An internal combustion engine system including a multi-cylinder internal combustion engine, in which fuel injection is performed for each of cylinders, the internal combustion engine system comprising:
A vehicle comprising:
An air-fuel ratio imbalance state determination method of determining, in an internal combustion engine system including a multi-cylinder internal combustion engine, in which fuel injection is performed for each of cylinders, and an air-fuel ratio detection device that detects an air-fuel ratio and that is provided in an exhaust pipe, at which flows of exhaust gas from the cylinders of the internal combustion engine are combined, whether the internal combustion engine is in an air-fuel ratio imbalance state, in which there is an imbalance in air-fuel ratio between the cylinders of the internal combustion engine of the internal combustion engine system, the method comprising
Dependencies are inferred from the claim text.