A controller for an internal combustion engine of a spark ignition type is provided. When stopping combustion in a cylinder in a situation in which a crankshaft of the internal combustion engine is rotating, one of a fuel cut process and a fuel feeding process is selectively executed. When combustion is resumed in the cylinder in which the combustion has been stopped, an enrichment process is executed to control a fuel injection valve so that an air-fuel ratio is set to be richer than a stoichiometric air-fuel ratio. When the enrichment process is executed, a decrease amount of an oxygen storage amount of the three-way catalyst corresponding to the enrichment process is set.

The present invention provides a catalyst diagnosis device that enables precisely grasping a variation of AFR and diagnosing a deteriorated condition of the catalyst based on the variation. A timer counts elapsed time Tosc until downstream AFU (AFRd) meets a predetermined threshold condition when the fuel injection quantity is corrected by increasing or decreasing it so that as to the AFRu, the transition from either of leanness or richness to the other is repeated with the stoichiometric area between the leanness and the richness. An OSA calculating section calculates an Oxygen Storage Amount (OSA) as a function of the AFR, Mfuel, Ne and Tosa. An OPA calculating section calculates an Oxygen Purge Amount (OPA) as a function of the AFR, Mfuel, Ne and Topa. A deterioration diagnosing section diagnoses a deteriorated condition of the catalyst C on the basis of at least one of the OSA and OPA.

A method for regulating filling an exhaust gas component (EGC) storage of a catalytic converter (CC) in the exhaust gas (EG) of an internal combustion engine. An actual fill level (AFL) of the EGC storage is ascertained using a first system model (FSM), to which signals of a first EG sensor projecting into the EG flow upstream from the CC and detecting a concentration of the EGC and a second EG sensor, downstream from the CC and exposed to the EG, are fed. A base lambda setpoint value for a first control loop (CL) is predefined by a second CL, which is adjusted to the AFL using the AFL ascertained using the FSM when the voltage of the second EG sensor indicates a breakthrough of rich/lean EG downstream from the CC and an excessively low/high AFL of the EGC storage. Also described is a control unit to perform the method.

A method is described for regulating a filling of an exhaust gas component storage of a catalytic converter in the exhaust gas of an internal combustion engine, in which an actual fill level of the exhaust gas component storage is ascertained using a first system model, and in which a base lambda setpoint value for a first control loop is predefined by a second control loop. The method is distinguished by the fact that in the second control loop an initial value for the base lambda setpoint value is converted into a fictitious fill level via a system model identical to the first system model, the fictitious fill level being compared with a setpoint value for the fill level output by a setpoint value generator, and the base lambda setpoint value being iteratively changed as a function of the comparison result, if the comparison result indicates a difference between the setpoint value for the fill level and the fictitious fill level, which is greater than a predefined degree, and the base lambda setpoint value not being changed if the comparison result indicates no difference between the setpoint value for the fill level and the fictitious fill level.

An apparatus includes a processing circuit structured to receive a first signal indicative of an upstream air-fuel equivalence ratio from a first sensor positioned upstream of an intake of a catalyst, receive a second signal indicative of a downstream airfuel equivalence ratio from a second sensor positioned downstream of the intake of the catalyst, determine an actual oxygen storage capacity of the catalyst based at least in part on the received first signal and the received second signal, compare the actual oxygen storage capacity to a maximum storage capacity, and provide a fault signal in response to the actual oxygen storage capacity exceeding the maximum storage capacity. The apparatus also includes a notification circuit structured to provide a notification indicating that the second sensor is faulty in response to receiving the fault signal.

An apparatus for exhaust gas purification comprises a filter function. The apparatus includes a gas-permeable substrate which forms a wall-flow filter that forms channels. The channels are sealed at least at one end and exhaust gas is flowable through the channels and gas-permeable channel walls of the channels formed from the substrate. A surface of the substrate is provided with an oxygen-storing coating. The mass of an oxygen-storing material coated on the surface of the substrate on an outflow side is higher than the mass of the oxygen-storing material coated on the surface of the substrate on an inflow side.

The invention relates to a method for controlling a filling level of an exhaust gas component accumulator of a catalytic converter (26) in the exhaust gas of an internal combustion engine (10), in which an actual filling level (.sub.mod) of the exhaust gas component accumulator is determined with a first catalytic converter model (100). The method is characterized in that a lambda setpoint (.sub.in,set) is formed, wherein a predetermined target fill level (.sub.set,flt) is converted into a base lambda setpoint by means of a second system model (104) which is the reverse of the first catalytic converter model (100), a deviation of the actual fill level (.sub.mod) from the predetermined target fill level (.sub.set,flt) is determined and processed to a lambda setpoint correction value by means of a fill level control unit (124), a sum of the base lambda setpoint value and the lambda setpoint value correction value is formed, and said sum is used to form a correction value, with which fuel metering to at least one combustion chamber (20) of the internal combustion engine (10) is influenced.

The invention relates to a method for adjusting a fuel/air ratio of an internal combustion engine (10), comprising a catalyst volume (26) with a first catalyst partial volume (26.1) and a second catalyst partial volume (26.2). The second catalyst partial volume (26.2) is arranged downstream from the first catalyst partial volume (26.1). An actual filling level of an exhaust gas constituent in the catalyst volume (26) is calculated from operating parameters of the internal combustion engine (10) and the exhaust system (14) using a computing model, and is adjusted to a nominal value by modifying the fuel/air ratio. The adjustment is carried out first for the second catalyst partial volume (26.2) and only later for the first catalyst partial volume (26.1).

Methods and systems are provided for an exhaust aftertreatment arrangement. In one example, a system includes a LNT upstream of an SCR with an oxygen storage component arranged therebetween, and where a rich operation of an engine is limited based on an oxygen load of the oxygen storage component when an exhaust gas temperature is higher than a limit temperature.

A control apparatus and a control method for an internal combustion engine of the present invention integrates an operating time in a state in which temperature TCAT of an exhaust gas purification catalyst is lower than a first temperature, to obtain first integrated time IT1, senses oxygen storage capacity OSC of the exhaust gas purification catalyst, and has a regeneration treatment of sulfur poisoning carried out when first integrated time IT1 exceeds first time THT1 and oxygen storage capacity OSC falls below first capacity OSC1, and furthermore, integrates an operating time in a state in which temperature TCAT of the exhaust gas purification catalyst is higher than second temperature TCAT2, to obtain second integrated time IT2, and has a regeneration treatment of oxidation poisoning carried out when second integrated time IT2 exceeds second time THT2.