In the disclosure, an F/B correction coefficient correcting a fuel injection amount so that a detected equivalence ratio detected by an LAF sensor becomes a target equivalence ratio is calculated by using a feedback control containing a predetermined gain, and a reference F/B correction coefficient is further set. By changing a valve overlap characteristic between an intake valve and an exhaust valve in a supercharging state, a scavenging control that scavenges a combustion chamber by blow-by of intake air is executed. During the scavenging control, when the F/B correction coefficient is changing relative to the reference F/B correction coefficient in a direction of further correcting the fuel injection amount to a rich side, the gain of the feedback control is reduced.

An engine control device includes a determination unit configured to determine whether or not an engine is in a complete explosion state, a calculation unit configured to calculate an integrated intake air amount that is an integrated value of an intake air amount of the engine after an affirmative determination is made by the determination unit, a setting unit configured to set a target equivalent ratio of the engine in accordance with the integrated intake air amount, and a control unit configured to control an intake air amount and a fuel injection amount of the engine such that an equivalent ratio of an air-fuel mixture becomes the target equivalent ratio.

Provided is an engine control device for correcting output characteristics of an oxygen sensor and performing air-fuel ratio feedback control. The engine control device includes various sensors for detecting operating state information of an engine, an oxygen sensor, and air-fuel ratio feedback controller to adjust an amount of fuel injected into the engine, on the basis of the operating state information and an output voltage value of the oxygen sensor, wherein the air-fuel ratio feedback controller calculates, in accordance with the operating state information based on detection results from the various sensors, a coefficient for correcting the output voltage value, implements air-fuel ratio feedback control on the basis of an air-fuel ratio feedback control correction amount calculated using a corrected oxygen sensor output voltage value calculated on the basis of the coefficient, and adjusts the amount of fuel injected into the engine.

An air-fuel ratio controller of an internal combustion engine includes an open-loop processor setting a base injection amount, a feedback processor calculating a feedback operation amount, an increase processor performing an increase correction on the base injection amount when a temperature of the internal combustion engine is a specified temperature or lower, an operation processor operating a fuel injection valve based on the corrected base injection amount and that is corrected using the feedback operation amount and a learning value, and an update processor updating the learning value. If the increase processor performs the increase correction, the update processor updates the learning value to increase an increase correction rate of the base injection amount when a temperature of the cylinder wall surface is high.

Methods and systems are provided for detecting exhaust gas oxygen sensor degradation due to sealant off-gassing. In one example, a method may include indicating exhaust gas oxygen sensor degradation due to sealant off-gassing responsive to a change in fueling demand without a change in driver-demanded torque after a threshold exhaust temperature has been reached. In response to the indication, a measurement correction may be learned and applied to measurements of the exhaust gas oxygen sensor in order to accurately determine an air-fuel ratio of the exhaust.

A delay module, based on a base request received for a first loop, sets a delayed base request for a second loop. A first period between the first and second loops corresponds to: a first delay period of an oxygen sensor; and a second delay period for exhaust to flow from a cylinder of an engine to the oxygen sensor. A closed loop module determines a closed loop correction for the second loop based on: the delayed base request for the second loop; a measurement from the oxygen sensor; the closed loop correction for the first loop; and the closed loop correction for a third loop. A second period between the second and third loops corresponds to the first delay period of the oxygen sensor. A summer module sets a final request for the second loop based on the base request plus the closed loop correction for the second loop.

A control system for carburation of an internal combustion engine in use conditions comprising following activities: starting the engine with a value of equals .sub.0=.sub.T; constructing a curve c.sub.i() of the ionization current as a function of the angular position a of the crank shaft; selecting, on this curve c.sub.i(), a number of points at intervals of the rotation angle a; calculating value z, equal to integral from 0 to 360 of the curve c.sub.i(), is done by summing products c.sub.i for all preselected points; interrupting supply of fuel for some cycles in order to externally modify factor .sub.0 and take it to value .sub.1; for value .sub.1 constructing curve c.sub.i() and calculating value z.sub.1; calculating difference .sub.z=z.sub.1z.sub.0, and if the difference is >.sub.zref in absolute value, intervening on carburation by increasing the quantity of fuel injected in a case of a positive difference (lean mixture) and by reducing the quantity of fuel injected in a case of a negative difference (rich mixture).

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 method of controlling a fuel injection quantity using a lambda sensor may include performing a lambda deviation learning mode by controlling a lambda deviation, due to a difference between a lambda model value and a lambda sensor measurement value, by a controller during engine combustion in which an engine RPM and a fuel injection quantity are detected, wherein, in the lambda deviation learning mode, a learning map is learned and is then updated by setting a fuel correction quantity depending on the lambda deviation as a learning value, and a fuel injection quantity is determined, in consideration of the fuel correction quantity depending on an RPM and a fuel quantity based on the updated learning map, and is output as an output value, so that the output value is applied to feedback control for a next fuel injection quantity.

A delay module, based on a base request received for a first loop, sets a delayed base request for a second loop. A first period between the first and second loops corresponds to: a first delay period of an oxygen sensor; and a second delay period for exhaust to flow from a cylinder of an engine to the oxygen sensor. A closed loop module determines a closed loop correction for the second loop based on: the delayed base request for the second loop; a measurement from the oxygen sensor; the closed loop correction for the first loop; and the closed loop correction for a third loop. A second period between the second and third loops corresponds to the first delay period of the oxygen sensor. A summer module sets a final request for the second loop based on the base request plus the closed loop correction for the second loop.