Methods and systems are provided for an auto-ignition internal combustion engine comprising an exhaust gas recirculation arrangement, an intake system, and an exhaust gas discharge system for the discharge of exhaust gases, in which the internal combustion engine is operable, at least in a first, stoichiometric operating mode, by way of a spatial ignition method (HCCI mode). For the aftertreatment of the exhaust gas in the first operating mode, a three-way catalytic converter is provided in the exhaust gas discharge system for reducing nitrogen oxides and oxidizing unburned hydrocarbons and carbon monoxide. In this way, the auto-ignition internal combustion engine has a greater window of operation in the HCCI mode than conventional auto-ignition internal combustion engines.

The present invention relates to a method for cleaning exhaust gas, and a correspondingly designed exhaust gas system. The present method, or the corresponding system, serves to avoid the formation of nitrous oxide as a secondary exhaust gas, which may primarily be created during the loading of specific catalyst types with NH.sub.3.

Provided are a novel synthesis technique for producing pure phase aluminosilicate zeolite and a catalyst comprising the phase pure zeolite in combination with a metal, and methods of using the same. The pure phase aluminosilicate zeolite can be selected from those having an ITW framework and a silica to alumina ratio of less than about 140 or, an STW framework and a silica to alumina ratio less than about 100.

An exhaust system for a combustion engine includes first and second catalytic converters arranged downstream of the combustion engine in a flow direction of exhaust gas. First and second exhaust pipes extend from the combustion engine to the first and second catalytic converters, respectively, with a first valve disposed in the first exhaust pipe, and a second valve disposed in the second exhaust pipe. The first and second valves operate such that in the presence of an exhaust temperature which is equal to or less than a limit value, at least the first valve opens to allow exhaust gas from the combustion engine to flow through the first catalytic converter, and that the first valve closes and the second valve opens, when the exhaust temperature is greater than the limit value to thereby allow exhaust gas from the combustion engine to flow through the second catalytic converter.

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.

The present invention relates to the use of different regeneration strategies for nitrogen oxide storage catalysts (NOx storage catalyst, LNT or NSC), depending on the exhaust gas temperatures, to reduce in the total exhaust gas the greenhouse gas N.sub.2O (nitrous oxide) that is produced as a secondary emission during the regeneration of the storage catalyst. If the exhaust gas temperature is below 275° C.-290° C., regeneration takes place using a strategy with short pulses of around 2 seconds and λ Lambda 0.95 rich.

A control device for a compression ignition engine includes a controller configured to operate an engine body by compression ignition combustion when the engine body operates in a predetermined compression ignition range. When the engine body operates in a predetermined high load range of the compression ignition range, the controller maximizes a filling amount of the cylinder using a gas state adjustment system, and lowers an EGR ratio so that the air-fuel mixture in the cylinder is lean with an excess air ratio λ higher than 1 in a lower speed range, and maximizes the filling amount of the cylinder, and increases the EGR ratio so that the air-fuel mixture in the cylinder has the excess air ratio λ of 1 or lower in a higher speed range than the lower speed range.

Reductant delivery systems are disclosed that include a dry reductant source and a liquid reductant source which are operable to selectively provide gaseous reductant and liquid reductant to an exhaust aftertreatment system for treatment and reduction of NOx emissions. The gaseous reductant is provided to the exhaust aftertreatment system for treatment of NOx emissions under a first temperature condition associated with the exhaust system and the liquid reductant for treatment of NOx emissions under a second temperature condition associated with the exhaust system.

A method of calculating an ammonia (NH3) mass generated in a lean NOx trap (LNT) of an exhaust purification device includes sequentially calculating a NH3 mass flow at a downstream of each slice from a first slice to an n-th slice, and integrating the NH3 mass flow at the downstream of the n-th slice over a predetermined time, wherein the calculation of the NH3 mass flow at the downstream of the i-th slice comprises calculating a NH3 mass flow flowing into the i-th slice, calculating a NH3 mass flow generated at the i-th slice, and adding the NH3 mass flow generated at the i-th slice to a value obtained by subtracting the NH3 mass flow used to reduce the NOx and the O2 at the i-th slice from the NH3 mass flow flowing into the i-th slice.