A controller for controlling operation of an aftertreatment system that is configured to treat constituents of an exhaust gas produced by an engine, the aftertreatment system including a selective catalytic reduction (SCR) catalyst, the controller configured to: generate a short-term cumulative degradation estimate of the SCR catalyst corresponding to reversible degradation of the SCR catalyst due to sulfur and/or hydrocarbons based on a SCR catalyst temperature parameter; generate a long-term cumulative degradation estimate of the SCR catalyst corresponding to thermal aging of the SCR catalyst based on the SCR catalyst temperature parameter; generate a combined degradation estimate of the SCR catalyst based on the short-term cumulative degradation estimate and the long-term cumulative degradation estimate; and adjust an amount of reductant and/or an amount of hydrocarbons inserted into the aftertreatment system based on the combined degradation estimate of the SCR catalyst.

A method for diagnosing a plurality of lambda sensors which are arranged upstream of an exhaust gas catalytic converter in a plurality of exhaust gas banks of a multi-flow exhaust gas system of an internal combustion engine. An opposite lambda offset of the lambda sensors is identified (54) when a difference (ΔT) between a measured exhaust gas temperature (T.sub.measure) and a modeled exhaust gas temperature (T.sub.mod) downstream of the exhaust gas catalytic converter overshoots a threshold value (S).

The invention relates to a method for automatically detecting clogging of a sensor pipe extending between a pressure sensor and an exhaust manifold of an internal combustion engine, wherein the pressure sensor enables to record a signal representative of the relative pressure over time. The method includes at least one of the following steps: a) determining, while the engine runs in a steady operation state, an average amplitude of oscillations of the signal over a first period of time, the sensor pipe being considered clogged when said average amplitude is lower than a first threshold; b) monitoring, from the time the engine has been turned off, the signal over a second period of time, the sensor pipe being considered clogged when the integral of the signal is greater than a second threshold.

A method for predicting soot build-up in an engine system when operating according to an intended drive cycle. The engine system includes an internal combustion engine and an exhaust gas aftertreatment system provided with a particulate filter. The method includes providing data representing engine operational conditions for the internal combustion engine during the intended drive cycle, wherein the data comprises values for at least engine speed and engine torque distributed over a time period representing the intended drive cycle; determining a working temperature for the exhaust gas aftertreatment system during the intended drive cycle based on the data representing the engine operational conditions; providing a reference relation between working temperature of the exhaust gas aftertreatment system and a corresponding estimated magnitude of a build-up of soot in the exhaust gas aftertreatment system; and predicting soot build-up in the engine system when operating according to the intended drive cycle by comparing the determined working temperature for the exhaust gas aftertreatment system with the reference relation.

A lean-burn internal combustion engine and an exhaust aftertreatment system having an oxidation catalyst are described. A controller determines a fueling rate and a mass flowrate of the exhaust gas feedstream. An inlet temperature of the exhaust gas feedstream upstream of the oxidation catalyst is determined via the first temperature sensor, and an in-use outlet temperature of the exhaust gas feedstream is determined downstream of the oxidation catalyst via the second temperature sensor. An expected outlet temperature from the oxidation catalyst is determined based upon the inlet temperature, the fueling rate, and the mass flowrate of the exhaust gas feedstream. The oxidation catalyst is evaluated based upon the expected outlet temperature and the in-use outlet temperature.

The present disclosure shows a system for checking a correct mounting of a plurality of sensors, in particular of sensors mounted in an engine system, comprising a controller configured for receiving signals from the plurality of sensors. The controller is configured to monitor a sequence and/or timing of the signals received from the sensors and to evaluate it with respect to a sequence and/or timing of a switching of a power supply to the sensors for checking the correct mounting of the sensors.

A method for detecting a replacement of a differential pressure sensor arranged for measuring a differential pressure across a filter of an aftertreatment system of a vehicle. The method includes determining a sensor offset value being an offset from a sensor value measured with a differential pressure sensor; adding an adaption value to the measured sensor value to compensate for the offset value to centre the sensor value around a predetermined level; if a sum of a subsequently measured sensor value and the adaption value exceeds a limit value, concluding that the differential pressure sensor has been replaced.

Engine systems and methods use a dual air injection approach to control exhaust reactions and to maintain temperatures below a maximum limit of exhaust system components during engine enrichment operation conditions. Dual air injectors are disposed in the exhaust system with one upstream from, and another downstream from, the catalytic converter. Providing air injection before and/or after the converter helps convert all HC, CO, and PM emissions while keeping the catalyst temperature below the catalyst protection temperature limit. Air injection quantity may be controlled and diagnosed by monitoring the temperatures before and after the catalytic converter. The catalytic converter may be a three-way catalytic converter for lower cost or a downstream two-way catalytic converter may be added if further emission reduction is necessary.

An exhaust gas treatment system for an internal combustion engine includes an exhaust gas pathway configured to receive exhaust gas from the internal combustion engine, a first treatment element positioned within the exhaust gas pathway, the first treatment element including a selective catalytic reduction (SCR) element, a first injector configured to selectively introduce ammonia gas into the exhaust gas pathway upstream of the first treatment element, a second injector configured to introduce diesel exhaust fluid into the exhaust gas pathway downstream of the first treatment element, and a second treatment element positioned within the exhaust gas pathway downstream of the second injector, the second treatment element including a SCR element.

Disclosed are methods and systems for monitoring a diesel generator system that includes a DPF filter in order to provide a highly efficient approach for monitoring the status of a DPF filter in order to determine if a regeneration is required. The methods and systems not only permit the ongoing determination of when a regeneration is appropriate in order to prevent excessive engine backpressure, but also accomplish this objective in a manner that reduces fuel consumption over the course of engine use.