A method for operating an exhaust-gas burner (B) of a vehicle (100) which has at least an internal combustion engine (V) and a catalytic converter (C1, C2), wherein exhaust gases (22, 24) of the exhaust-gas burner (B) are merged, upstream of the catalytic converter (C1, C2), with exhaust gases (12) of the internal combustion engine (V), forming an exhaust-gas mixture, wherein a lambda value of the exhaust gases (22, 24) of the exhaust-gas burner (B) is set in a manner dependent on a lambda value of the exhaust gases (12) of the internal combustion engine (V).

The present disclosure describes methods for evaluating quality of DEF dosed to an EAS including a close coupled SCR unit a downstream SCR unit. A NOx conversion efficiency of the close coupled SCR unit and a NOx conversion efficiency of the downstream SCR unit are used to evaluate quality of DEF. In some embodiments, the NOx conversion efficiency of close coupled SCR unit is used to evaluate quality of DEF. Operation of an EAS using the results of the evaluation of quality of DEF are described.

In a method for operating a urea dosing system in an exhaust aftertreatment system (EATS) of an engine, an ambient temperature is measured in an environment in which the EATS is disposed, one or more temperatures associated with the EATS to which there is a relationship to a temperature of area in the urea dosing system are monitored. After turning off the engine, whether urea in the urea dosing system is subject to freezing is determined based on the measured ambient temperature and the one or more monitored temperatures. A reversion operation is performed after turning off the engine with a delay until one or more events occur, the one or more events including determining that urea in the urea dosing system is subject to freezing. An engine system is also provided.

A method for detecting the icing of a particulate filter, especially of a gasoline particulate filter, includes determining the temperature of the exhaust gas flow flowing through the particulate filter, whereby icing of the particulate filter is detected on the basis of the determined temperature of the exhaust gas flow. The method is improved in that the temperature of the exhaust gas flow upstream from the particulate filter and the temperature of the exhaust gas flow downstream from the particulate filter are determined, whereby on the basis of the measured temperature difference, the heat input into the particulate filter and the quantity of water present in the particulate filter are determined, whereby the aggregates states of the water present in the particulate filter are calculated by drawing up a balance of the heat quantity.

A method includes providing electric power to an exhaust aftertreatment system component, where the exhaust aftertreatment system component is one of a particulate filter and an electrically heated catalyst. The method includes obtaining an impedance value of the exhaust aftertreatment system component in response to providing the electric power. The method includes determining a structural state of the exhaust aftertreatment system component based on the impedance value.

A selective catalytic reduction (SCR) system is provided for treating exhaust gas in an exhaust passage. The system comprises a hydrolysis catalyst located in the exhaust passage, and a diesel exhaust fluid (DEF) dosing unit configured to inject DEF onto the hydrolysis catalyst. A SCR catalyst is located in the passage downstream of the hydrolysis catalyst, and a controller controls DEF dosing by the dosing unit. The controller is configured to control the DEF dosing unit such that the DEF is injected at a modulated frequency of less than or equal to 1 Hertz. A method of treating exhaust gas in an exhaust passage using an SCR system is also provided.

An exhaust gas aftertreatment system includes: a first sensor configured to measure a parameter in the exhaust gas aftertreatment system; a second sensor configured to measure the parameter in the exhaust gas aftertreatment system, the second sensor disposed proximate the first sensor; and at least one controller configured to simultaneously receive sensor values from the first sensor and receive sensor values from the second sensor.

A method of detecting a need for regeneration of an exhaust particulate filter is described. A first pressure drop is detected in a flow section of an exhaust system which includes the exhaust particulate filter. In addition, an exhaust gas temperature is determined. An exhaust gas mass flow flowing through the exhaust particulate filter is then calculated on the basis of the exhaust gas temperature and the pressure drop. Furthermore, a second pressure drop at the exhaust particulate filter is determined. A need for regeneration is detected when the second pressure drop exceeds a predefined pressure limit value that is dependent on the exhaust gas mass flow. Moreover, an exhaust system for an internal combustion engine is presented which includes an exhaust particulate filter.

A vehicle exhaust system including an exhaust pipe section, a selective catalytic reduction (SCR) catalyst, and a burner assembly, connected to the exhaust pipe section at a position upstream of the selective catalytic reduction (SCR) catalyst, for pre-heating the exhaust system prior to engine start-up. The burner assembly includes a burner with a combustion chamber and a connecting tube that extends between the burner and the exhaust pipe section. A metallic mesh filter element is located inside the connecting tube and/or a catalytic washcoat is disposed on an inner surface of the connecting tube to reduce emissions of the burner assembly at start-up. The catalytic washcoat comprises a mixture of a support material and a catalyst material that chemically reacts with emissions generated by the burner to reduce the amount of burner produced emissions released from the exhaust system during pre-heating.

A controller for an aftertreatment system coupled to an engine is configured to: in response to receiving an engine shutdown signal, determine an estimated amount of ammonia stored on a selective catalytic reduction (SCR) catalyst included in the aftertreatment system; in response to determining that the estimated amount of ammonia stored in the SCR catalyst is less than an ammonia storage threshold, cause flow of a heated gas towards the SCR catalyst; cause insertion of a reductant into an exhaust gas flowing through the aftertreatment system; and in response to determining that the estimated amount of ammonia stored in the SCR catalyst is equal to or greater than the ammonia storage threshold, cause shutdown of the engine.