A method is proposed for regulating a fill level of an exhaust component storage of a catalyst (26) of an internal combustion engine (10), wherein the regulating of the fill level is done by using a system model (100), comprising a catalyst model (102), and wherein uncertainties of measured or model variables influencing the regulating of the fill level are corrected by an adaptation, which is based on signals of an exhaust gas probe (34) arranged at the outlet side of the catalyst (26). The method is characterized in that the adaptation takes multiple pathways (200, 210, 220), wherein signals from different signal regions (260, 280, 300) of the exhaust gas probe (34) situated at the outlet side are processed on different pathways. An independent claim is addressed to a controller designed to carry out the method.

Systems and methods of preventing thermal spikes at a catalyst in an exhaust system of an engine of a vehicle include detecting whether one of a fuel enrichment event and a fuel cutoff event has been initiated and in response, temporarily disabling the other of the fuel enrichment event and the fuel cutoff event from occurring to prevent an exhaust gas temperature thermal spike that could damage the catalyst, while the other of the fuel enrichment event and the fuel cutoff event is disabled, performing stoichiometric closed-loop fuel control using the one or more oxygen sensors to drive the exhaust gas fuel/air ratio to stoichiometry and an oxygen storage capacity of the catalyst to a balanced state, and when measurements from the one or more oxygen sensors indicate at least one lean-to-rich transition and one rich-to-lean transition in the exhaust gas oxygen level has occurred, re-enabling the other event.

Technical methods described herein include an emissions control system for treating exhaust gas from an internal combustion engine in a motor vehicle. The emissions control system includes a three-reaction oxygen storage model. The system further includes a three-way catalyst and a controller that controls an oxygen storage level for the three-way catalyst. The controller determines a first reaction rate representing a net rate of cerium oxidation by oxygen, a second reaction rate representing a net rate of cerium reduction by carbon monoxide, and a third reaction rate representing a net rate of cerium reduction by hydrogen. The controller further determines the oxygen storage level based on the first reaction rate, the second reaction rate, and the third reaction rate.

The present disclosure relates to assessing the intake air flow of industrial engines. For an industrial engine that receives vent gas added to intake air for combustion, a gas concentration sensor is used to measure a concentration of a particular gas, e.g. methane, in the intake air. An amount of the methane component in the intake air flowing to the engine that was added by the vent gas can be determined from the measured concentration of methane in the intake air and a flow rate of the intake air. The intake air flow rate may be directly measured, or calculated using instrumentation which may already be in place for engine air-to-fuel ratio control.

The internal combustion engine comprises an exhaust purification catalyst and downstream side air-fuel ratio sensor. The control system 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 and performs learning control which corrects the control center air-fuel ratio based on the output air-fuel ratio of the downstream side air-fuel ratio sensor. The target air-fuel ratio is switched between the lean air-fuel ratio and the rich air-fuel ratio. In the learning control, when the target air-fuel ratio is set to the rich air-fuel ratio and the output air-fuel ratio of the downstream side air-fuel ratio sensor is maintained in an air-fuel ratio region in proximity to the stoichiometric air-fuel ratio for the stoichiometric air-fuel ratio judgment time or more, stoichiometric air-fuel ratio stuck learning is performed, changing air-fuel ratio of the exhaust gas to the rich side.

An exhaust purification system of the internal combustion engine comprises: an upstream side catalyst 20 arranged in an exhaust passage, a downstream side catalyst 24 arranged at a downstream side of the upstream side catalyst, an air-fuel ratio sensor 41 detecting an air-fuel ratio of outflowing exhaust gas flowing out from the upstream side catalyst, an air-fuel ratio control part 31 controlling an air-fuel ratio of inflowing exhaust gas flowing into the upstream side catalyst to a target air-fuel ratio, and a temperature calculating part 32 calculating a temperature of the downstream side catalyst. The air-fuel ratio control part switches the first control to the second control when a temperature of the downstream side catalyst calculated by the temperature calculating part rises to a reference temperature which is equal to or higher than an activation temperature of the downstream side catalyst.

A method for operating an internal-combustion engine having an exhaust gas catalyst, a first exhaust gas sensor upstream of the exhaust gas catalyst and a second exhaust gas sensor downstream of the exhaust gas catalyst. A fill level of an exhaust gas component that can be stored in the exhaust gas catalyst is determined using a theoretical catalyst model, into which, as the input value, a signal of the first exhaust gas sensor (a first signal); a signal of the second exhaust gas sensor (a second signal); and a target signal are provided. The target signal corresponds to the signal that would be expected at the determined fill level in the exhaust gas catalyst. The catalyst model is reinitiated when the deviation of the second signal from the target signal exceeds a predetermined threshold value. The fill level is also regulated, and an air-fuel mixture is adjusted.

A method for controlling a fill level of a catalytic converter that is in an exhaust aftertreatment system of an exhaust tract downstream from an internal combustion engine includes an exhaust gas sensor that is upstream of the catalytic converter measuring, and producing a signal representing, a concentration of an exhaust component; correcting a dynamic distortion present in the produced signal to produce a corrected signal; determining the fill level of the catalytic converter by inputting the corrected signal into a modeling function; and performing a control that modifies the fill level based on the determined fill level.

A method for checking a load condition of a particulate filter in an exhaust line of an internal combustion engine, wherein the exhaust line comprises at least the particulate filter, a first lambda sensor that is arranged upstream from the particulate filter, and a second lambda sensor that is arranged downstream from the particulate filter, includes at least the following steps: introducing an exhaust gas with an excess of oxygen into the exhaust line upstream from the first lambda sensor, there being a temperature of at least 500 C. in the particulate filter; detecting the excess of oxygen by the first lambda sensor at a first time; detecting the excess of oxygen by the second lambda sensor at a second time; and determining a load condition of the particulate filter from a time difference between the first time and the second time. The invention further relates to an exhaust system of a motor vehicle.

Disclosed is a method for diagnosis of an oxygen probe for a combustion engine, with the steps: When an engine's fuel injection is inactive, measuring the output electric voltage from the oxygen probe; If the measured output electrical voltage of the oxygen probe is greater than a predetermined minimum voltage threshold, measuring a pressure prevailing in an intake distributor of the engine; If the measured pressure in the intake distributor is less than a predetermined minimum pressure threshold, increasing the pressure to a value greater than the predetermined minimum pressure threshold; Determining the time period between the time when the output electrical voltage of the probe falls below a second predetermined voltage threshold and the time when the output electrical voltage of the probe falls below a third predetermined voltage threshold; and diagnosing the oxygen probe depending on elapsed the time period.