Abstract: An internal combustion engine is provided that performs stoichiometric burn operation under control for providing a stoichiometric air-fuel ratio as basic control for an air-fuel ratio. A particulate filter (PM filter) is provided in an exhaust passage of the engine to trap particulate matter PM contained in exhaust gas. If it is judged that the PM filter will have excessively elevated temperature, fuel cut is prohibited during deceleration. Otherwise, before the prohibition of the fuel cut, the air-fuel ratio of exhaust gas is controlled so that the atmosphere of the PM filter is brought into an atmosphere slightly leaner than the stoichiometric air-fuel ratio.

Abstract: An object of the present invention is to provide an exhaust gas purifying apparatus for an internal combustion engine which can successfully achieve a good balance between reduction of exhaust emission and removal of particulate matter PM. An upstream side three-way catalyst 18 without OSC materials is disposed in an exhaust pipe 14 immediately below an exhaust manifold 12 of an internal combustion engine 10. A particulate filter (PM filter) 20 for trapping the particulate matter PM contained in exhaust gas is disposed at a downstream side of the upstream side three-way catalyst 18. A downstream side three-way catalyst 22 with the OSC materials is disposed at a downstream side of the PM filter 20.

Abstract: The present invention relates to an air-fuel ratio control device for an internal combustion engine, and makes it possible to maintain high purification performance by suppressing a decrease in the oxygen occlusion capability of a catalyst. When an O2 sensor output oxs is greater than a reference value oxsref, which corresponds to a stoichiometric air-fuel ratio, and smaller than an upper threshold value oxsrefR, a sub-FB reflection coefficient is fixed at a predetermined value vdox2 for providing a lean air-fuel ratio. When, on the other hand, the O2 sensor output oxs is smaller than the reference value oxsref and greater than a lower threshold value oxsrefL, the sub-FB reflection coefficient is fixed at a predetermined value vdox2 for providing a rich air-fuel ratio. The sub-FB reflection coefficient reflects the O2 sensor output oxs in the calculation of a fuel injection amount and increases or decreases to have a consequence on the air-fuel ratio of an exhaust gas.

Abstract: A air-fuel ratio control apparatus, applied to an internal combustion engine having a catalyst disposed in an exhaust passage of the engine, includes a downstream air-fuel ratio sensor (oxygen concentration cell type oxygen concentration sensor) disposed at a position downstream of the catalyst, and air-fuel ratio control means for controlling, based on an output value of the downstream air-fuel ratio sensor, an air-fuel ratio of a mixture supplied to the engine so as to change an air-fuel ratio of a catalyst inflow gas. Further, the air-fuel ratio control means controls the air-fuel ratio of the mixture supplied to the engine.

Abstract: An air-fuel ratio control system of a multi-cylinder internal combustion engine provided with a throttle valve and opening characteristic control means, which system performs feedback control of an air-fuel ratio based on an output of a sensor detecting an air-fuel ratio of exhaust gas and is capable of performing more accurate air-fuel ratio control, is provided. In the feedback control, the relationship of the output of the sensor and a feedback value is corrected based on a feedback learning correction value learned and determined based on the output of the sensor during the feedback control, and, when newly learning the feedback learning correction value, the intake air amount is controlled by only the throttle valve.

Abstract: The air-fuel ratio of exhaust gas supplied to a catalyst is alternately and actively switched between a rich state value and a lean state value. In conjunction with the performance of this active air-fuel ratio control, the oxygen storage capacity of the catalyst is measured. Whether the catalyst is normal or abnormal is determined by comparing the measured value of the oxygen storage capacity with a predetermined determination value. The temperature of the catalyst is acquired, and the determination value is set based on the acquired catalyst temperature. The determination value is set so as to decreases with increasing catalyst temperature when the catalyst temperature is equal to or higher than a predetermined temperature.

Abstract: A target air-fuel ratio of exhaust gas is changed back and forth between rich and lean in short periods, and it is determined that the catalyst is degraded when the air-fuel ratio of exhaust gas is lean by the time a predetermined period of time has passed from the time the target air-fuel ratio started to be changed.

Abstract: An ammonia burning internal combustion engine in which, in addition to ammonia, a reformed gas reformed at a reformer is fed into a combustion chamber. When a reforming ability of the reformer is less than a predetermined reforming ability, an ammonia ratio is increased to a ratio more than the ammonia ratio after completion of engine warmup set in advance in accordance with an operation state of the engine, and secondary air is fed from a secondary air feeding device into an engine exhaust passage upstream of an exhaust purification catalyst.

Abstract: A control system of an internal combustion engine in which a first fuel of ammonia and a second fuel which is easier to burn than ammonia are used as fuels. An ammonia ratio is usually set to a reference ammonia ratio which is determined in advance in accordance with an operating state of an engine. At the time when feed of the fuel is restarted after suspension of feed of the fuel at the time of deceleration, the ammonia ratio is temporarily made lower than the reference ammonia ratio in accordance with the operating state of the engine.

Abstract: During deterioration detection of a catalyst, exhaust gas of a lean air/fuel ratio and exhaust gas of a rich air/fuel ratio are alternately supplied to the catalyst, and decrease of the O2 storage function is detected by obtaining the oxygen occlusion amount in the catalyst, based upon the timing at which, after changeover of the air/fuel ratio of the exhaust gas flowing into the catalyst, the air/fuel ratio of the exhaust gas passed through the catalyst changes to track that air/fuel ratio of the exhaust gas flowing into the catalyst. At this time, the rich air/fuel ratio of the exhaust gas and the lean air/fuel ratio of the exhaust gas supplied to the catalyst are set closer to the stoichiometric air/fuel ratio, the larger is the exhaust flow amount.

Abstract: A catalyst for purifying exhaust gases includes a carrier substrate and a catalyst layer which is carried on the carrier substrate and contains a noble metal, a porous oxide and an additional oxide containing at least one selected from the group consisting of Ni, Bi, Sn, Fe, Co, Cu and Zn. Only a downstream section of the carrier substrate, which is located on a downstream side of an exhaust gas stream contains the additional oxide, whereas an upstream section of the carrier substrate does not contain the additional oxide. With this arrangement, in the upstream section of the carrier substrate, the noble metal and the additional oxide do not exist together so that the noble metal is not deteriorated with the additional oxide. As a result, in the upstream section, the purification performance as a three-way catalyst is favorably achieved, thereby restraining the emission of H2S while maintaining the three-way performance.

Abstract: A fuel injection amount is controlled so that the air-fuel ratio of exhaust gas flowing into a catalyst (6) oscillates around a stoichiometric air-fuel ratio. When it is estimated that the level of oxygen storage capacity of the catalyst (6) is lower than a predetermined reference capacity, the amplitude of the air-fuel ratio of the exhaust gas which oscillates around the stoichiometric air-fuel ratio is reduced by controlling the fuel injection amount. The level of the oxygen storage capacity of the catalyst (6) is estimated based on the amplitude of the output signal from an oxygen sensor (14) disposed downstream of the catalyst (6).

Abstract: An internal combustion engine is provided that performs stoichiometric burn operation under control for providing a stoichiometric air-fuel ratio as basic control for an air-fuel ratio. A particulate filter (PM filter) is provided in an exhaust passage of the engine to trap particulate matter PM contained in exhaust gas. If it is judged that the PM filter will have excessively elevated temperature, fuel cut is prohibited during deceleration. Otherwise, before the prohibition of the fuel cut, the air-fuel ratio of exhaust gas is controlled so that the atmosphere of the PM filter is brought into an atmosphere slightly leaner than the stoichiometric air-fuel ratio.

Abstract: An exhaust passage of an internal combustion engine is provided with an upstream side three-way catalyst capable of purifying exhaust gas and a particulate filter (PM filter) for trapping particulate matter PM contained in exhaust gas. Catalyst warm-up control is exercised for the purpose of warming up mainly the upstream side three-way catalyst at cold start. Filter regeneration control for removing the particulate matter PM accumulating on the particulate filter from the filter is exercised at the cold start after the catalyst warm-up control is exercised.

Abstract: The combustion air-fuel ratio is made leaner than the stoichiometric air-fuel ratio at the time of engine startup and the combustion air-fuel ratio is made richer than the stoichiometric air-fuel ratio and the exhaust downstream part of the three-way catalyst apparatus is raised in temperature when it is judged that just the exhaust upstream part of the three-way catalyst apparatus arranged in the engine exhaust system has been raised to the catalyst activation temperature.

Abstract: An air-fuel ratio control device includes an air-fuel ratio sensor provided upstream from a three-way catalyst, and an oxygen sensor provided downstream from the three-way catalyst. The air-fuel ratio control device controls the fuel supply amount based on the output from the air-fuel ratio sensor, and compensates for errors in the air-fuel ratio sensor by correcting the fuel supply amount based on the output from the oxygen sensor. The fuel supply correction amount is calculated based on an integral term that integrates the deviation between the output from the downstream air-fuel ratio sensor and the target air-fuel ratio. When a fuel supply adjustment control is executed, the value of the integral term in the sub-feedback control is not updated for a predetermined period after the fuel supply adjustment control ends. The actual air-fuel ratio is thus brought to the target air-fuel ratio in an appropriate manner.

Abstract: In the present invention, in a control system for a spark ignition internal combustion engine, when a catalyst is not sufficiently active, the ignition timing is advanced to be earlier than MBT to decrease the quantity of hydrocarbons (HC) discharged from the internal combustion engine, and oxygen is supplied to the exhaust gas upstream of the catalyst to thereby oxidize carbon monoxide (CO) discharged from the internal combustion engine. According to this invention, exhaust emissions emitted before activation of the exhaust gas purification apparatus can be decreased as much as possible, and early activation of the catalyst can be achieved by making use of heat generated by oxidation reaction of carbon monoxide (CO).

Abstract: An air-fuel ratio control system of a multi-cylinder internal combustion engine provided with a throttle valve and opening characteristic control means, which system performs feedback control of an air-fuel ratio based on an output of a sensor detecting an air-fuel ratio of exhaust gas and is capable of performing more accurate air-fuel ratio control, is provided. In the feedback control, the relationship of the output of the sensor and a feedback value is corrected based on a feedback learning correction value learned and determined based on the output of the sensor during the feedback control, and, when newly learning the feedback learning correction value, the intake air amount is controlled by only the throttle valve.

Abstract: An object of the present invention is to provide an exhaust gas purifying apparatus for an internal combustion engine which can successfully achieve a good balance between reduction of exhaust emission and removal of particulate matter PM. An upstream side three-way catalyst 18 without OSC materials is disposed in an exhaust pipe 14 immediately below an exhaust manifold 12 of an internal combustion engine 10. A particulate filter (PM filter) 20 for trapping the particulate matter PM contained in exhaust gas is disposed at a downstream side of the upstream side three-way catalyst 18. A downstream side three-way catalyst 22 with the OSC materials is disposed at a downstream side of the PM filter 20.

Abstract: The present invention relates to an air-fuel ratio control device for an internal combustion engine, and makes it possible to maintain high purification performance by suppressing a decrease in the oxygen occlusion capability of a catalyst. When an O2 sensor output oxs is greater than a reference value oxsref, which corresponds to a stoichiometric air-fuel ratio, and smaller than an upper threshold value oxsrefR, a sub-FB reflection coefficient is fixed at a predetermined value vdox2 for providing a lean air-fuel ratio. When, on the other hand, the O2 sensor output oxs is smaller than the reference value oxsref and greater than a lower threshold value oxsrefL, the sub-FB reflection coefficient is fixed at a predetermined value vdox2 for providing a rich air-fuel ratio. The sub-FB reflection coefficient reflects the O2 sensor output oxs in the calculation of a fuel injection amount and increases or decreases to have a consequence on the air-fuel ratio of an exhaust gas.