An exhaust aftertreatment system and associated method for purifying an exhaust gas feedstream of a lean-burn or other compression-ignition internal combustion engine is described. An instruction set is executable to determine an engine-out NO2 concentration upstream of an oxidation catalyst and determine a first parameter associated with O2 concentration. A consumption of oxygen in the oxidation catalyst due to oxidation reactions is determined, and a concentration of NO2 generated by the oxidation catalyst is determined based upon the consumption of oxygen in the oxidation catalyst. A concentration of NO2 downstream of the oxidation catalyst is determined. A NO2/NOx ratio in the exhaust gas feedstream downstream of the oxidation catalyst is determined based upon the concentration of NO2 downstream of the oxidation catalyst and the NOx concentration measured by the downstream NOx sensor. The oxidation catalyst is evaluated based upon the NO2/NOx ratio.

Methods and systems are provided for estimation of a volume of liquid diesel exhaust fluid (DEF) contained within a DEF tank. In one example, a method for the estimation of the volume of liquid DEF in a DEF tank during DEF freezing conditions may include activating a heater contained within the DEF tank, and then switching estimation of the volume of liquid DEF via a first transfer function to estimation of the volume of liquid DEF via a second transfer function.

A reduction device includes a housing defining an input chamber configured to receive exhaust from a power source, an output chamber, an exhaust channel configured to direct the exhaust from the input chamber to the output chamber, and a longitudinal axis. The reduction device also includes a treatment unit disposed in the exhaust channel and along the longitudinal axis. The treatment unit is configured to at least partly remove pollutant species from the exhaust. The reduction device also includes an attenuation component disposed in the housing and radially outward of the treatment unit. The attenuation component is fluidly connected to the exhaust channel, and is configured to attenuate a range of frequencies corresponding to operation of the power source. Additionally, the exhaust channel prohibits exhaust entering the input chamber from exiting the housing without passing through the treatment unit.

Methods and systems are provided for adjusting a substitution ratio based on water in a combustion mixture of a multi-fuel engine. In one example, a method includes adjusting a substitution ratio in response to an amount of water provided to a multi-fuel engine configured to combust a first fuel and a second fuel, the second fuel different than the first fuel.

A method for controlling the operation of an engine system in a vehicle upon engine start. The engine system includes an engine and an exhaust aftertreatment system having a selective catalyst reduction, SCR, catalyst and a reductant dosing system for providing a reductant to the SCR catalyst. The method comprises: determining the temperature of the SCR catalyst; in response of determining that the temperature of the SCR catalyst is above a predetermined threshold, initiating pressurising of the reductant dosing system towards a predefined operating pressure; performing a preventive action for delaying engine start until the operating pressure of the reductant dosing system is reached.

A method for predicting urea crystal build-up in an engine system when operating according to an intended drive cycle. 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 values and time variation for at least one exhaust parameter during the time period of the intended drive cycle when the engine system is operated according to the engine operational condition data; providing a reference relation between values and time variation for the at least one exhaust parameter and an expected urea crystal build-up in the engine system when operating the engine system at different engine operational conditions, predicting urea crystal build-up in the engine system when operating according to the intended drive cycle by comparing the determined values and time variation for the at least one exhaust parameter 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.

An exhaust treatment system for a work vehicle includes a selective catalytic reduction (SCR) system having an SCR outlet for expelling treated exhaust flow therefrom, a flow conduit in fluid communication with the outlet, an exhaust sensor positioned within the flow conduit downstream of the outlet, and a flow mixer positioned upstream of the exhaust sensor. The flow mixer has an end wall defining sector openings circumferentially extending between first and second sector sides and radially between radially inner and outer sector ends. Moreover, the flow mixer has swirler vanes, where each of the swirler vanes extends circumferentially from the first sector side of a respective one of the sector openings and radially between radially inner and outer vane ends. Particularly, the radially outer vane end of each of the swirler vanes is spaced apart from the radially outer sector end of the respective one of the sector openings.

The present disclosure is directed towards a filter arrangement for a reductant supply system of a selective catalytic reduction system. The reductant supply system comprises a tank and a suction tube mounted at least partially in the tank for receiving reductant liquid from the tank. The filter arrangement comprises a restraining body, a filter at least partially forming a filter chamber, a filter outlet from the filter chamber formed through the restraining body and/or filter and a filter mount mounted to the restraining body and/or filter. The restraining body extends radially outwardly from the filter mount and is configured to restrain the filter such that, under the effect of buoyancy in the tank in use, gas in the filter chamber is directed towards the filter outlet.

A method detects a manipulation of an exhaust gas system, in which measured values are sent to an external checking unit by a control unit of the exhaust gas system. In the external checking unit, an evaluation of the exhaust gas system as “manipulated” or as “not manipulated” takes place. Model values are formed in the control unit, which are at least partially formed from the measured values which are sent to the external checking unit. The external checking unit takes the model values and the measured values into consideration in the evaluation of the exhaust gas system.