An apparatus includes a pump, a delivery mechanism in fluid communication with the pump, and a controller communicatively coupled to the pump and the delivery mechanism. The controller is structured to interpret, via a pump diagnostic circuit, first and second pump parameters indicative of first and second pump rates, interpret, via a dosing diagnostic circuit, first and second dosing parameters indicative of at least one of (i) first and second reductant flows or (ii) first and second injector characteristics, determine, via a delivery diagnostic circuit, a delivery status based, at least in part, on the interpretation of the first and second pump parameters and the first and second dosing parameters, and generate, via the delivery diagnostic circuit, a status command indicative at least one of an under-restricted delivery mechanism or an over-restricted delivery mechanism in response to the determination of the delivery status.

A process for detecting reductant deposits includes accessing data indicative of signal output from a radiofrequency sensor positioned proximate a decomposition reactor tube; comparing the data indicative of signal output from the radiofrequency sensor to a deposit formation threshold; and activating a deposit mitigation process responsive to the data indicative of signal output from the radiofrequency sensor exceeding the deposit formation threshold.

An aftertreatment system includes an exhaust reductant tank configured to store an exhaust reductant. A filter is fluidically coupled to the exhaust reductant tank. The aftertreatment system includes a hydrocarbon detection device configured to indicate the presence of a hydrocarbon in the exhaust reductant. A catalyst is included in the system and configured to treat the exhaust reductant flowing through the system. The hydrocarbon detection device can include a hydrophobic paper, and can be disposed in the filter.

An internal combustion engine comprises a filter and is configured to enable attachment of a secondary air feed system feeding air into exhaust gas flowing into the filter. A control device of the engine is configured, in the PM removal control for removing particulate matter deposited on the filter, to perform temperature raising processing for controlling the engine so that the air-fuel ratio of the exhaust gas discharged from the engine body 1 is a rich air-fuel ratio and for feeding air from the secondary air feed system, and to perform regeneration processing for controlling the engine so that the air-fuel ratio of the exhaust gas discharged from the engine body is a stoichiometric air-fuel ratio and for feeding air from the secondary air feed system so that the air-fuel ratio of the exhaust gas flowing into the filter is a lean air-fuel ratio.

Methods and systems using model based and iterative calculations of mass flow throughout an internal combustion engine system. A secondary air injection valve is provided to selectively allow intake air to pass to the exhaust side of the engine system to aid in exothermic reaction with exhaust gasses exiting the engine for various purposes. The iterative calculations of mass flow include estimation of the mass flow through the secondary air injection valve.

A method (200) for ascertaining an air volume provided by means of an electric air pump (134) in an exhaust system (120) of an internal combustion engine (110), including detecting at least one activation parameter (5) of the air pump and ascertaining (220) a provided air mass flow rate (8) on the basis of a calculation specification from the at least one activation parameter (5) by utilizing an inertia of the air pump (134) and/or an inertia of the air upstream and/or downstream from the air pump (134) and/or a differential pressure from upstream from the air pump to downstream from the air pump. In addition, a processing unit and a computer program for carrying out a method (200) of this type is provided.

An exhaust gas control apparatus includes an exhaust gas control catalyst disposed in an exhaust passage, a filter disposed downstream of the catalyst, a secondary air supply device configured to supply secondary air into exhaust gas flowing into the filter at a location downstream of the catalyst in an exhaust gas flow direction, and an electronic control unit. The electronic control unit is configured to, when a temperature of the catalyst is higher than or equal to an activation temperature and an air-fuel ratio of exhaust gas emitted from an engine body is a rich air-fuel ratio, cause the supply device to supply secondary air into exhaust gas while periodically increasing or reducing the air such that the air-fuel ratio of exhaust gas flowing into the filter alternately varies between rich and lean air-fuel ratios.

The invention relates to an exhaust aftertreatment system for an internal combustion engine that, at its outlet, is connected to an exhaust gas system. In the exhaust gas system, a three-way catalytic converter close to the engine, an electrically heatable three-way catalytic converter downstream from the three-way catalytic converter close to the engine, and further downstream, a particulate filter or a four-way catalytic converter are situated in the flow direction of an exhaust gas of the internal combustion engine through an exhaust duct of the exhaust gas system. In addition, the exhaust aftertreatment system includes a secondary air system with a secondary air pump and a secondary air line, which opens into the exhaust duct at an introduction point downstream from the three-way catalytic converter close to the engine and upstream from the electrically heatable three-way catalytic converter. The invention further relates to a method for regenerating a particulate filter or the four-way catalytic converter by use of such an exhaust aftertreatment system.

A method for operating an exhaust burner with a secondary air system downstream of a combustion engine of a motor vehicle. The method includes: activating an ignition device as a function of a release condition, the ignition device being heated up to a specifiable target temperature; metering fuel at a first time point into a combustion chamber of the exhaust burner at a first injection frequency using an injection valve, and the combustion chamber not being actively supplied with air; setting a first target air-mass flow using a secondary air system at a further, second time point, wherein the air-mass flow is increased strictly monotonically; controlling the air-fuel ratio to a first target air-fuel ratio as a function of a lambda sensor starting from the second time point, and metering fuel at a second injection frequency; setting a second target air-mass flow at a further, third time point.

A method for heating a catalytic converter includes a) switching on a compressor; b) at least partially opening an injection valve; c) setting a combustion-air/fuel ratio of <1 in combustion chambers; d) detecting an actual value of the oxygen content in the exhaust gas; and e) comparing the actual value with a target value, where the target value corresponds to an exhaust-gas oxygen content that would be set in a region of the catalytic converter if the combustion-air/fuel ratio in the combustion chambers is approximately =1, where a manipulated variable output by a controller on a basis of a deviation of the actual value from the target value is kept constant when the actual value reaches one of two limit values of a value range within which the target value is ranged, and where the two limit values deviate from the target value by approximately 3%.