摘要:
An upstream side catalyst and a downstream side catalyst are disposed in an exhaust passage. A first oxygen sensor is disposed between these two catalysts and a second oxygen sensor is disposed downstream of the downstream side catalyst. The air-fuel ratio is forcibly oscillated and the oxygen storage capacity of the upstream side catalyst is detected. Deterioration of the upstream side catalyst is then detected based on whether this oxygen storage capacity is larger than a predetermined value. The forced oscillation of the air-fuel ratio is performed only when the oxygen storage state of the downstream side catalyst is appropriate.
摘要:
An air-fuel ratio control apparatus estimates, on the basis of an exhaust air-fuel ratio of exhaust gas flowing into an exhaust purifying catalyst unit disposed in an exhaust passage of an engine, an emission of at least one specific component contained in exhaust gas flowing out of the exhaust purifying catalyst unit. The air-fuel ratio control apparatus performs the estimation by use of a model, and controls the air-fuel ratio in such a manner that the estimation value reaches a target state. The model is previously determined in consideration of the mass balance of the specific component.
摘要:
An air-fuel ratio control apparatus of an internal combustion engine according to the present invention is provided with oxygen storage amount estimating means, downstream exhaust air-fuel ratio detecting means, maximum oxygen storage amount estimating means, and air-fuel ratio target setting means. The oxygen storage amount estimating means estimates an oxygen storage amount of an exhaust purifying catalyst, based on a history of an oxygen adsorption/desorption amount of the exhaust purifying catalyst located on an exhaust path. The downstream exhaust air-fuel ratio detecting means is located downstream of the exhaust purifying catalyst and detects an exhaust air-fuel ratio downstream of the exhaust purifying catalyst. The maximum oxygen storage amount estimating means estimates a maximum oxygen storage amount, based on an oxygen storage amount estimate when the exhaust air-fuel ratio detected is a predetermined air-fuel ratio. This permits effective utilization of oxygen occlusion capability of the exhaust purifying catalyst and improvement in exhaust purification performance.
摘要:
An air-fuel ratio control apparatus of an internal combustion engine according to the present invention is provided with an oxygen storage amount estimator for estimating an oxygen storage amount of an exhaust purifying catalyst and air-fuel ratio control means for controlling an air-fuel ratio, based on the oxygen storage amount. An upper threshold and a lower threshold are set for the oxygen storage amount, and the air-fuel ratio controller performs such control that, when the oxygen storage amount is larger than the upper threshold, the controller controls the air-fuel ratio to a rich region and that, when the oxygen storage amount is smaller than the lower threshold, the controller controls the air-fuel ratio to a lean region. Since this control makes the oxygen storage amount vary between the upper threshold and the lower threshold (within a predetermined range), it is feasible to promote activation of the exhaust purifying catalyst, so as to keep purification performance of the exhaust purifying catalyst high, and to implement stable control of air-fuel ratio.
摘要:
In a control device, in a control device of an internal combustion engine provided with an internal combustion engine main body mounted to a vehicle and a heater operating on the basis of an output from a specific sensor given as a trigger at least before the internal combustion engine main body starts, whether or not the heater is operated before the start is stored, and it is judged that the sensor has failed when operation of the heater is not stored.
摘要:
An air-fuel ratio control apparatus of an internal combustion engine according to the present invention is provided with oxygen storage amount estimating means, downstream exhaust air-fuel ratio detecting means, maximum oxygen storage amount estimating means, and air-fuel ratio target setting means. The oxygen storage amount estimating means estimates an oxygen storage amount of an exhaust purifying catalyst, based on a history of an oxygen adsorption/desorption amount of the exhaust purifying catalyst located on an exhaust path. The downstream exhaust air-fuel ratio detecting means is located downstream of the exhaust purifying catalyst and detects an exhaust air-fuel ratio downstream of the exhaust purifying catalyst. The maximum oxygen storage amount estimating means estimates a maximum oxygen storage amount, based on an oxygen storage amount estimate when the exhaust air-fuel ratio detected is a predetermined air-fuel ratio. This permits effective utilization of oxygen occlusion capability of the exhaust purifying catalyst and improvement in exhaust purification performance.
摘要:
A catalytic emission control apparatus of an internal combustion engine that has an engine stop mode of stopping the internal combustion engine during a run of a vehicle utilizes an oxygen absorption-storage action of an emission control catalyst disposed in an exhaust passage of the internal combustion engine. The emission control apparatus has a storage computing device that computes a storage of oxygen in the emission control catalyst, and air-fuel ratio controller performs an air-fuel ratio control of the internal combustion engine based on the storage of oxygen computed by the storage computing device. The storage computing device computes the storage of oxygen during the engine stop mode of the internal combustion engine. The air-fuel ratio controller performs the air-fuel ratio control when the internal combustion engine is restarted after the engine stop mode is discontinued, based on the storage of oxygen computed by the storage computing device during the engine stop mode.
摘要:
An air-fuel ratio control system for an internal combustion engine estimates an oxygen storage amount of a catalyst based on a record of an oxygen storage amount, and controls an air-fuel ratio based on the estimated oxygen storage amount. The catalyst is divided into multiple sections in a flow direction of an exhaust gas, the oxygen storage amount in a specified section is estimated according to a behavior of an exhaust gas on upstream and downstream sides of the respective specified sections, and the air-fuel ratio is controlled based on the estimated oxygen storage amount in the specified section.
摘要:
A catalyst degradation determining method includes the steps of: controlling an upstream-of-catalyst air-fuel ratio occurring upstream of a first catalyst to an air-fuel ratio that is rich of a stoichiometric air-fuel ratio so that first and second catalysts store oxygen up to a maximum storage amount of oxygen. The method then includes the steps of controlling the upstream-of-catalyst air-fuel ratio to a first lean air-fuel ratio until an output of a downstream-of-first-catalyst sensor indicates a lean air-fuel ratio, and then to a second lean air-fuel ratio and that has a value that is determined in accordance with an oxidizing-reducing capability index value, until a time point when an output of a downstream-of-second-catalyst air-fuel ratio sensor indicates an air-fuel ratio that is lean.
摘要:
A catalyst degradation determining method includes the steps of: controlling an upstream-of-catalyst air-fuel ratio occurring upstream of a first catalyst to an air-fuel ratio that is rich of a stoichiometric air-fuel ratio so that first and second catalysts store oxygen up to a maximum storage amount of oxygen. The method then includes the steps of controlling the upstream-of-catalyst air-fuel ratio to a first lean air-fuel ratio until an output of a downstream-of-first-catalyst sensor indicates a lean air-fuel ratio, and then to a second lean air-fuel ratio and that has a value that is determined in accordance with an oxidizing-reducing capability index value, until a time point when an output of a downstream-of-second-catalyst air-fuel ratio sensor indicates an air-fuel ratio that is lean.