Systems and methods for determining fuel delay in a fuel injected engine with cylinders that may be deactivated are presented. In one example, the fuel injection delay is determined via a cylinder firing schedule array when the cylinder firing schedule array is available. The fuel injection delay is determined via weighted average of a fuel injection delay of a present engine cycle and a fuel injection delay of a past engine cycle when the cylinder firing schedule array is not available.

A control method of an engine system is a method of controlling the engine system including an engine with a combustion chamber; a fuel injection valve configured to supply fuel to the engine; and an air-fuel ratio sensor provided in a flow path of exhaust gas from the engine. In the control method, feedback control is performed so that an air-fuel ratio in the combustion chamber becomes a target value by controlling the fuel injection valve, using an air-fuel ratio measured value obtained by the air-fuel ratio sensor. In the feedback control, a transfer function is used, the transfer function being obtained by system identification of a plant having the air-fuel ratio in the combustion chamber serve as an input and the air-fuel ratio measured value obtained by the air-fuel ratio sensor serve as an output. In the control method, a filtering process is performed to an air-fuel ratio measured value used in the feedback control, the filtering process cutting a component having a response speed faster than a delay indicated by the transfer function.

In a case where an internal combustion engine is executing an all-cylinder operation to operate all cylinders, an air-fuel ratio estimation part of an ECU 1 estimates an air-fuel ratio of each of the cylinders by using a first observer. On the other hand, in a case where the internal combustion engine is executing a cylinder-cut operation to rest a part of the cylinders and to operate other of the cylinders, the air-fuel ratio estimation part does not estimate the air-fuel ratio of each of the cylinders by using the first observer.

A control method of an engine system is a method of controlling the engine system including an engine with a combustion chamber; a fuel injection valve configured to supply fuel to the engine; and an air-fuel ratio sensor provided in a flow path of exhaust gas from the engine. In the control method, feedback control is performed so that an air-fuel ratio in the combustion chamber becomes a target value by controlling the fuel injection valve, using an air-fuel ratio measured value obtained by the air-fuel ratio sensor. In the feedback control, a transfer function is used, the transfer function being obtained by system identification of a plant having the air-fuel ratio in the combustion chamber serve as an input and the air-fuel ratio measured value obtained by the air-fuel ratio sensor serve as an output. In the control method, a filtering process is performed to an air-fuel ratio measured value used in the feedback control, the filtering process cutting a component having a response speed faster than a delay indicated by the transfer function.

An oxygen sensor system includes an oxygen sensor and associated circuitry connected thereto. The oxygen sensor including a reference cell. The associated circuitry measures the impedance of the reference cell at time intervals, wherein the time intervals include a random component.

An oxygen sensor system includes an oxygen sensor and associated circuitry connected thereto. The oxygen sensor including a reference cell. The associated circuitry measures the impedance of the reference cell at time intervals, wherein the time intervals include a random component.

A control system for vehicles that controls drive force and acceleration smoothly without causing a shock, in response to an operation of an accelerator pedal. A hysteresis is set between an input value and an output value of angle of the accelerator pedal. The hysteresis includes a deadband and an asymptotic range. The output value is not changed significantly with respect to a change in the input value if an angle of the accelerator pedal is changed within the deadband, and the output value is changed continuously with respect to a change in the input value based on a predetermined function if an angle of the accelerator pedal is changed within the asymptotic range.

Systems and methods for determining fuel delay in a fuel injected engine with cylinders that may be deactivated are presented. In one example, the fuel injection delay is determined via a cylinder firing schedule array when the cylinder firing schedule array is available. The fuel injection delay is determined via weighted average of a fuel injection delay of a present engine cycle and a fuel injection delay of a past engine cycle when the cylinder firing schedule array is not available.

Systems and methods for injecting fuel to an engine in response to a fuel injection delay are presented. The method includes determining fuel delay in a fuel injected engine with cylinders that may be deactivated. In one example, the fuel injection delay is determined via a cylinder firing schedule array when the cylinder firing schedule array is available. The fuel injection delay is determined via a weighted average of a fuel injection delay of a present engine cycle and a fuel injection delay of a past engine cycle when the cylinder firing schedule array is not available.

Disclosed herein is a method for diagnosing and controlling a two-step exhaust variable valve lift (VVL) system, including: a controlling device acquiring an operation state signal of a vehicle; when the vehicle is in the over-run state, the controlling device outputting a mode conversion signal of the two-step exhaust VVL system; an air mass sensor measuring an air mass entering an engine, and the controlling device comparing a predetermined prediction value of the air mass with the measured air mass; when a difference of the compared air mass corresponds to a predetermined mode conversion comparing amount, the controlling device determining that a mode conversion of the two-step exhaust VVL system is completed; and when the difference of the compared air mass does not correspond to the mode conversion comparing amount, the controlling device determining that the two-step exhaust VVL system is faulty and outputting a result thereof.