An exhaust system that includes a catalytic converter, selective catalytic reduction system, a muffler and, for certain applications, a diesel particulate filter that each include at least one filter that has an electric heating element, a metallic coating and a plurality of metal rods extending therethrough. The combination of elements are configured to heat the internal housings of the exhaust system and disrupt the direction of flow of exhaust gases which contain harmful toxic gases and pollutants and aid in removing and/or reducing said toxic gases and pollutants.

A heavy duty truck includes a diesel engine, an exhaust after-treatment system, and an engine control unit. The exhaust after-treatment system may include one or more selective catalytic reduction systems, each with a respective heater, and each heater with a respective pair of temperature sensors, one upstream and the other downstream of the heater. Such systems may be used to perform diagnostic methods including populating a lookup table having heat energy supplied to an exhaust gas stream by the diesel engine as a first independent variable, heat energy supplied to the exhaust gas stream by a heater as a second independent variable, and a resulting temperature as an output. Such a lookup table can be used to maintain a temperature of the exhaust gas flow at a constant target temperature.

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.

An aftertreatment system for treating an exhaust gas comprises an exhaust conduit, a preheating oxidation catalyst, a primary oxidation catalyst disposed downstream of the preheating oxidation catalyst, and a selective catalytic reduction system disposed in the exhaust conduit downstream of the primary oxidation catalyst. A controller is configured to determine a temperature of an exhaust gas at an inlet of the selective catalytic reduction system. In response to the temperature being below a threshold temperature, the controller generates a hydrocarbon insertion signal configured to cause hydrocarbons to be inserted into or upstream of the preheating oxidation catalyst so as to increase a temperature of the exhaust gas to above the threshold temperature.

An after-treatment system includes, in series along an exhaust gas flow direction through the after-treatment system: a diesel oxidation catalyst (DOC) or a passive NOx adsorber (PNA), a diesel exhaust fluid (DEF) delivery device, a soot-reducing device and a selective catalytic reduction (SCR) catalyst, which may also include an additional PNA.

A method of starting up a thermoreactor arranged in an exhaust gas flow of an internal combustion engine includes igniting combustion gas by spark ignition in at least one cylinder of the internal combustion engine. The exhaust gas resulting from the combustion of the combustion gas is fed at least partially to the thermoreactor as an exhaust gas flow. The temperature of the exhaust gas resulting from combustion of the combustion gas is increased by the moment in time of the spark ignition being selected later in comparison with a present moment in time.

An engine exhaust system includes an exhaust pipe assembly having an engine exhaust system inlet configured to receive engine exhaust and an engine exhaust system outlet. The system includes a first selective catalytic reduction (SCR) catalyst device positioned downstream in exhaust flow from the engine exhaust system inlet. The first SCR catalyst device includes a substrate with a metallic catalyst coated on the substrate. An electric heater is configured to heat the metallic catalyst. A second SCR catalyst device is positioned downstream in engine exhaust flow from the first SCR catalyst device and upstream of the engine exhaust system outlet. The first SCR catalyst device and the exhaust pipe assembly define an empty chamber between the substrate and the second SCR catalyst device. Engine exhaust flows directly from the substrate to the second SCR catalyst device through the empty chamber.

An exhaust system injection section (10) includes an exhaust gas flow channel (19), a laterally arranged injector connection (21), with a fluid introducing injector (22) and an injection chamber (24) formed in the channel, which is delimited by a perforated first separating wall (25), arranged in the channel upstream of the injector connection, and a perforated second separating wall (26) arranged in the channel downstream of the injector connection. To provides intensive mixing of the injected fluid with the exhaust gas flow a perforation (29) of the first separating wall (25) is configured so that exhaust gas largely flows eccentrically through the first separating wall (25) with respect to a longitudinal center axis (23) of the channel and a perforation (31) of the second separating wall (26) is configured so that exhaust gas largely flows concentrically through the second separating wall (26) with respect to the longitudinal center axis (23).

This control device for an internal combustion engine equipped with an exhaust purification catalyst, which is disposed in an exhaust passage of the internal combustion engine and capable of storing oxygen, includes: a downstream air-fuel ratio detection means that is disposed downstream of the exhaust purification catalyst in the exhaust flow direction; and an inflow air-fuel ratio control means that controls the air-fuel ratio of exhaust gas flowing into the exhaust purification catalyst. If the outflow air-fuel ratio detected by the downstream air-fuel ratio detection means is equal to or less than a rich-determination air-fuel ratio, which is richer than the stoichiometric air-fuel ratio, the inflow air-fuel ratio control means sets the target air-fuel ratio of exhaust gas flowing into the exhaust purification catalyst continuously or intermittently leaner than the stoichiometric air-fuel ratio until the oxygen storage amount of the exhaust purification catalyst reaches a prescribed storage amount. If the oxygen storage amount of the exhaust purification catalyst is equal to or greater than the prescribed storage amount, the inflow air-fuel ratio control means sets the target air-fuel ratio continuously or intermittently richer than the stoichiometric air-fuel ratio until the oxygen storage amount decreases toward zero without reaching the maximum oxygen storage amount.

A method for controlling regeneration a catalyst by an exhaust gas purification device includes: measuring a temperature of exhaust gas flowing into a first catalyst unit; estimating a NO.sub.x amount loaded into the first catalyst unit and a slip amount of NO.sub.x of the first catalyst unit by using the temperature and an amount of the exhaust gas of the first catalyst unit; calculating a temperature of a second catalyst unit by using the temperature of the first catalyst unit; and estimating a NO.sub.x amount flowing into the second catalyst unit by using at least one of the slip amount of NO.sub.x of the first catalyst unit and the temperature of the second catalyst unit.