Disclosed is a device for injecting ammonia in gaseous form into an exhaust line of a combustion engine, the device including a supervisor, an evaporation chamber incorporating a heater for heating a quantity of reducing agent thus releasing ammonia in gaseous form that exits the evaporation chamber via a pipe opening into the exhaust line. The control supervisor is associated with an internal first pressure sensor housed in the evaporation chamber and with a second pressure sensor intended to be housed in the exhaust line, including a calculator calculating a quantity of ammonia to be injected into the exhaust line at a given instant as a function of the pressure values from the first and second pressure sensors.

A reductant injecting device includes: a honeycomb structure comprising: a pillar shaped honeycomb structure portion having a partition wall that defines a plurality of cells each extending from a fluid inflow end face to a fluid outflow end face; and at least one pair of electrode portions arranged on a side surface of the honeycomb structure portion; an outer cylinder being configured to house the honeycomb structure, the outer cylinder having a carrier gas introduction port on the fluid inflow end face side; a urea sprayer arranged at one end of the outer cylinder; a carrier gas introduction cylinder provided at the carrier gas introduction port of the outer cylinder; and a carrier gas flow rate amplifier provided in the carrier gas introduction cylinder.

Disclosed is a device for injecting ammonia in gaseous form into an exhaust line of a combustion engine, the device including a supervisor, an evaporation chamber incorporating a heater for heating a quantity of reducing agent thus releasing ammonia in gaseous form that exits the evaporation chamber via a pipe opening into the exhaust line. The control supervisor is associated with an internal first pressure sensor housed in the evaporation chamber and with a second pressure sensor intended to be housed in the exhaust line, including a calculator calculating a quantity of ammonia to be injected into the exhaust line at a given instant as a function of the pressure values from the first and second pressure sensors.

A decrease in an NOx removal or reduction rate at the time of filter regeneration is suppressed. To this end, provision is made for an NOx selective reduction catalyst, a filter arranged at the upstream side of the NOx selective reduction catalyst, an NH.sub.3 generation catalyst arranged at the upstream side of the NOx selective reduction catalyst to generate NH.sub.3 when the air fuel ratio of an exhaust gas is equal to or less than a stoichiometric air fuel ratio, a regeneration unit to carry out regeneration of the filter, and a generation unit to make the air fuel ratio of the exhaust gas equal to or less than the stoichiometric air fuel ratio, thereby causing NH.sub.3 to be generated in the NH.sub.3 generation catalyst, wherein the regeneration unit inhibits the regeneration of the filter until the generation of NH.sub.3 by the generation unit is completed.

The present invention relates to an installation for depollution of the exhaust gas circulating in an exhaust line (10), notably from an internal-combustion engine, comprising at least one catalysis means for selective catalytic reduction of nitrogen oxides (NOx), at least one particle elimination means, a main tank (26) comprising at least one particle reducing agent and means (20) for feeding the reducing agent into the exhaust line. According to the invention, the installation comprises reducing agent additivation means (30).

An after treatment system is disclosed. The after treatment system may include a three-way catalyst (TWC), a selective catalytic reduction (SCR) catalyst, and a CO clean-up catalyst (CUC) on an exhaust pipe through which an exhaust gas flows. The CUC may include a zeolite in which Cu and Fe are ion-exchanged and CeO.sub.2 in which Pt is supported, wherein a weight ratio of the CeO.sub.2 to a total weight of the CUC is 30-70 wt % such that the CUC purifies NH.sub.3 at a lean air/fuel ratio and purifies NH.sub.3 during a delay time at a rich air/fuel ratio.

A reductant injecting device includes: a honeycomb structure comprising: a pillar shaped honeycomb structure portion having a partition wall that defines a plurality of cells each extending from a fluid inflow end face to a fluid outflow end face; and at least one pair of electrode portions arranged on a side surface of the honeycomb structure portion; an outer cylinder being configured to house the honeycomb structure, the outer cylinder having a carrier gas introduction port on the fluid inflow end face side; a urea sprayer arranged at one end of the outer cylinder; a carrier gas introduction cylinder provided at the carrier gas introduction port of the outer cylinder; and a carrier gas flow rate amplifier provided in the carrier gas introduction cylinder.

A reductant injecting device includes: a honeycomb structure comprising: a pillar shaped honeycomb structure portion having a partition wall that defines a plurality of cells each extending from a fluid inflow end face to a fluid outflow end face; and at least one pair of electrode portions arranged on a side surface of the honeycomb structure portion; an inner cylinder being configured to house the honeycomb structure; a urea sprayer arranged at one end of the inner cylinder; and an outer cylinder arranged on an outer peripheral side of the inner cylinder, the outer cylinder being spaced apart from the inner cylinder. A flow path through which the carrier gas passes is formed between the inner cylinder and the outer cylinder.

The present disclosure provides a method of treating a diesel exhaust system that includes heating a reagent to a temperature such that at least a portion of the reagent is heated to a gaseous phase, injecting the reagent into a diesel exhaust stream upstream of a catalyst, and reacting the diesel exhaust with the heated reagent over the catalyst to convert NO.sub.x into N.sub.2 and H.sub.2O. The heating modulates a mass flow rate of the reagent by converting a state of matter of the reagent at least partially to the gaseous phase prior to or after being injected, and the heated reagent in the gaseous form reduces deposit formations within the diesel exhaust system.

An after treatment system for a lean-burn engine is disclosed. The after treatment system is sequentially equipped with an ammonia production catalyst module, a selective catalytic reduction (SCR) catalyst, and a CO clean-up catalyst (CUC) on an exhaust pipe through which an exhaust gas flows and which is connected to a lean-burn engine. An exhaust flow changer is disposed between the ammonia production catalyst module and the SCR catalyst. The exhaust flow changer changes flow of an exhaust gas discharged from the ammonia production catalyst module according to a temperature of the SCR catalyst.