An oxygen storage/release material includes: a ceria-zirconia composite oxide porous body that has at least one ordered phase of a pyrochlore phase and a phase, and that has a central pore diameter of 70 nm to 1 m as measured by a mercury penetration method, and in which a cumulative pore volume of pores that each have a pore diameter in the range of 0.5 times to 2 times the central pore diameter is 40% or more of the cumulative pore volume of pores that each have a pore diameter in the range of 10 nm to 10 m as measured by the mercury penetration method.

A system includes an exhaust aftertreatment system including a particulate filter and a controller. The controller is configured to: receive information comprising a temperature regarding a filter of the aftertreatment system; and responsive to determining that the temperature regarding the filter is below a temperature threshold, command the engine to operate according to a first firing fraction. The first firing fraction may define a number of active cylinders of the engine relative to a total number of cylinders of the engine, and correspond to a predetermined temperature value of the filter.

An internal combustion engine comprises: an exhaust purification catalyst; a downstream side air-fuel ratio sensor which is arranged at a downstream side of the exhaust purification catalyst; and an air-fuel ratio control system which performs feedback control so that the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst becomes a target air-fuel ratio. The air-fuel ratio control system switches the target air-fuel ratio to a lean set air-fuel ratio when the air-fuel ratio detected by the downstream side air-fuel ratio sensor becomes a rich judged air-fuel ratio or less; changes the target air-fuel ratio to a slight lean set air-fuel ratio after switching the target air-fuel ratio to the lean set air-fuel ratio and before an estimated value of the oxygen storage amount of the exhaust purification catalyst becomes a switching reference storage amount or more; and switches the target air-fuel ratio to a rich air-fuel ratio when the estimated value of the oxygen storage amount of the exhaust purification catalyst becomes the switching reference storage amount or more.

A particle filter for an internal combustion engine has a filter body (2) with a first channel (5) having a first end (7) facing a filter inlet (3) and a second end (8) facing a filter outlet (4), and a flow-through second channel (6) having a third end (9) facing the filter inlet (3) and a fourth end (10) formed facing the filter outlet (4). The second and third ends (8, 9) cannot accommodate flow therethrough. The channels (5, 6) are divided into a flow-through section (13) and a non-flow-through section (14). A wall (11) between the channels (5, 6) enables soot particles to be separated from exhaust gas flowing through the filter body (2) from the first channel (5) into the second channel (6). The non-flow-through channel section (14) has a heating element (15) to increase a reaction temperature in the filter (1) for burning off the soot particles.

In a control system for an internal combustion engine in which an exhaust gas purification catalyst having a lower catalyst layer and an upper catalyst layer disposed at the upper side of the lower catalyst layer is arranged in an exhaust passage of the internal combustion engine, when an operation at a rich air fuel ratio is switched to an operation at a target lean air fuel ratio, switching is made through a first operation in which the air fuel ratio of exhaust gas is temporarily made into a lean air fuel ratio, and a second operation which is carried out after the first operation and in which the air fuel ratio of the exhaust gas is made to change alternately between the rich air fuel ratio and the lean air fuel ratio a plurality of times, whereby the HC poisoning of the catalyst can be recovered at an early stage.

An exhaust purification system comprises an air-fuel ratio control device. If the air-fuel ratio detected by the downstream side air-fuel ratio sensor 41 reaches a second judged air-fuel ratio, the air-fuel ratio control device sets the target air-fuel ratio to a third set air-fuel ratio when the air-fuel ratio reaches the second judged air-fuel ratio, and switch the target air-fuel ratio from the third set air-fuel ratio to the second set air-fuel ratio when the air-fuel ratio becomes a value at the stoichiometric air-fuel ratio side from the second judged air-fuel ratio. The first set air-fuel ratio, the first judged air-fuel ratio and the second judged air-fuel ratio are an air-fuel ratio in the first region. The second set air-fuel ratio and the third set air-fuel ratio are an air-fuel ratio in a second region at an opposite side from the first region.

An internal combustion engine comprises an exhaust purification catalyst and a downstream side air-fuel ratio sensor which is arranged at a downstream side of the exhaust purification catalyst. A control system can perform fuel cut control which stops the feed of fuel to the internal combustion engine during operation of the internal combustion engine, and, after the end of fuel cut control, performs post-return rich control which sets the exhaust air-fuel ratio to a rich air-fuel ratio. The control system correct the output air-fuel ratio of the downstream side air-fuel ratio sensor, based on a difference between the stoichiometric air-fuel ratio and the output air-fuel ratio in the output stabilization time period, which is a time period when the amount of change per unit time of the output air-fuel ratio of the downstream side air-fuel ratio sensor is a predetermined value or less, in the time period after the end of the fuel cut control and before the output air-fuel ratio of the downstream side air-fuel ratio sensor becomes a rich judged air-fuel ratio or less.

Technical solutions are described for limiting exposure of components of an emissions control system to rich exhaust conditions. An example an emissions control system includes an oxygen storage component; and a controller that limits exposure of the oxygen storage component to rich exhaust conditions. The limiting includes determining an air-to-fuel equivalence ratio in exhaust gas in response to an engine receiving a request to generate torque, the request including a displacement of a pedal; determining an amount of oxygen in the exhaust gas based on the air-to-fuel equivalence ratio; determining an oxygen level stored by the oxygen storage component; and if the oxygen level is above a predetermined threshold, lowering a torque generation rate of the engine, which specifies amount of torque generated per unit displacement of the pedal.

A method for detecting catalyst deterioration in a vehicle includes executing a fuel-cut mode of an engine of the vehicle according to a operating state of the vehicle; calculating an oxygen storage capacity (OSC) of a catalyst using an oxygen sensor during the executing of the fuel-cut mode of the engine; and calculating catalyst deterioration based on the calculated OSC.

A control system of an internal combustion engine which can suppress a drop in the purification performance of an exhaust purification catalyst is provided. The control system of an internal combustion engine is provided with an exhaust purification catalyst and downstream side air-fuel ratio sensor, performs feedback control so that an air-fuel ratio of the exhaust gas which flows into the exhaust purification catalyst becomes a target air-fuel ratio, and performs target air-fuel ratio setting control which alternately switches the target air-fuel ratio to a lean set air-fuel ratio which is leaner than a stoichiometric air-fuel ratio and a rich set air-fuel ratio which is richer than the stoichiometric air-fuel ratio. In the control system, when an engine operating state is a steady operating state, compared with when it is not a steady operating state, at least one of a rich degree of the rich set air-fuel ratio or a lean degree of the lean set air-fuel ratio is made to increase.