Provided is a combustion system using a catalyst having better denitration efficiency at low temperatures, during a selective catalytic reduction reaction in which ammonia is used as a reducing agent. This combustion system comprises: a combustion device that combusts fuel; an exhaust path through which flows exhaust gas generated from the combustion of fuel in the combustion device; a dust collection device that is arranged on the exhaust path and collects soot/dust in the exhaust gas; and a denitration device that is arranged on the exhaust path and removes nitrogen oxides from the exhaust gas by means of a denitration catalyst, wherein the denitration device is arranged downstream of the dust collection device on the exhaust path, and the denitration catalyst contains vanadium oxide, has a carbon content of 0.05 wt % or more, and has a defect site in which oxygen deficiency occurs in a crystal structure.

A heating device for an exhaust system of an internal combustion engine and having: a tubular body, where a combustion chamber is obtained on the inside; a fuel injector, which is designed to inject fuel into the combustion chamber; at least one inlet opening, which can be connected to a fan so as to receive an air flow, which is directed to the combustion chamber; a feeding channel, which receives air from the inlet opening, surrounds an end portion of the fuel injector and ends with a nozzle, which is arranged around a spray tip of the fuel injector, from which fuel flows out; and a spark plug, which is mounted through a side wall of the tubular body. An axial distance, namely measured along a longitudinal axis of the tubular body, between the spray tip of the fuel injector and a longitudinal axis of the spark plug ranges from 33% to 100% of an inner diameter of the tubular body.

A heating device for an exhaust system of an internal combustion engine and having: a tubular body, where a combustion chamber is obtained on the inside; a fuel injector, which is designed to inject fuel into the combustion chamber; at least one inlet opening, which can be connected to a fan so as to receive an air flow, which is directed to the combustion chamber; a feeding channel, which receives air from the inlet opening, surrounds an end portion of the fuel injector and ends with a nozzle, which is arranged around an injection point of the fuel injector; and a spark plug, which is mounted through a side wall of the tubular body. The feeding channel is delimited, on the outside, by an outer tubular body. The fuel injector is configured to spray at least part of the fuel against the outer tubular body, which has a through opening, through which a spray tip of the fuel injector letting out the fuel directly aims at the electrodes of the spark plug.

An internal combustion engine system, including an internal combustion engine (ICE), an exhaust aftertreatment system (EATS) located downstream of said ICE. An exhaust gas recirculation (EGR) pump arranged in an exhaust gas recirculation duct extending between the ICE and EATS, wherein the ICE system has a normal operation mode for transporting, by means of the EGR pump, at least a portion of said exhaust gas to upstream of the ICE. The ICE system further includes a heating device arranged upstream of at least one exhaust aftertreatment devices of said EATS and the ICE system has a pre-heat operation mode for transporting, by means of the EGR pump, exhaust gas and/or air through said heating device and then to said at least one of said exhaust aftertreatment devices.

An exhaust-gas burner for an exhaust-gas system of a motor vehicle includes a combustion chamber, which is surrounded by an outer wall, for a channel section in an exhaust-gas system. A dosing unit is provided for the controlled feed of a fuel into the combustion chamber. An ignition unit is provided for the ignition of a combustible mixture in the combustion chamber. A cooling circuit is provided for the exchange of heat with the dosing unit, and is arranged within the outer wall of the exhaust-gas burner.

A holding device for an injection valve of an exhaust-gas burner of a motor vehicle includes a receiving section and a cooling-water jacket. The receiving section is shaped such that it can receive a front end of the injection valve. The cooling-water jacket extends around the receiving section and is shaped such that, after the holding device has been mounted on the exhaust-gas burner, the cooling-water jacket, together with a corresponding cooling-water jacket of the exhaust-gas burner, forms a cooling-water chamber of the exhaust-gas burner.

An exhaust-gas tract for a motor vehicle has an exhaust-gas burner that includes an air inlet connection for the introduction of air into the exhaust-gas burner. The air inlet connection has a connection piece in which a check valve for the closure of the connection piece is arranged. The air inlet connection has an air inlet flange which connects the connection piece to a combustion chamber of the exhaust-gas burner and which seals off the combustion chamber. A motor vehicle incorporates the exhaust-gas tract.

A heating device for an exhaust system of an internal combustion engine; the heating device has: a first tubular body wherein a combustion chamber is obtained; a fuel injector to inject fuel into the combustion chamber; an inlet opening, which is obtained through the first tubular body and can be connected to a fan to receive an air flow, which is directed into the combustion chamber; a hot air outlet opening to let hot air out of the combustion chamber; an outlet duct, which originates from the outlet opening; a spark plug which is mounted through a side wall of the first tubular body to trigger the combustion of a mixture of air and fuel; and a labyrinth, which surrounds a side wall of the tubular body, starts from the inlet opening, ends in the combustion chamber, and the air must necessarily flow out of the inlet opening until reaching the combustion chamber.

The invention relates to a regeneration air system for an exhaust aftertreatment system of an internal combustion engine and to such an exhaust aftertreatment system. The regeneration air system comprises a regeneration air delivery element, a regeneration air duct, and a regeneration air valve. A sensor system is provided in the regeneration air duct with which a regeneration air mass flow {dot over (m)}.sub.SL can be determined exactly. The exhaust aftertreatment system comprises an exhaust system with an exhaust duct in which, in the direction of flow of an exhaust gas through the exhaust duct, a three-way catalytic converter is arranged underhood and a four-way catalytic converter is arranged downstream. A provision is made that an intake point for the regeneration air from the regeneration air system is formed on the exhaust duct downstream from the underhood three-way catalytic converter and upstream from the four-way catalytic converter.

An exhaust gas aftertreatment system for an internal combustion engine comprises an exhaust gas system with an exhaust gas channel in which at least two exhaust gas aftertreatment components for the selective, catalytic reduction of nitrogen oxides are arranged. Downstream from the first exhaust gas aftertreatment component and upstream from the second exhaust gas aftertreatment component is a burner with which the exhaust gas can be heated up before it enters the second exhaust gas aftertreatment component. Downstream from the second exhaust gas aftertreatment component is an oxidation catalytic converter that converts unburned hydrocarbons. In a method for exhaust gas aftertreatment in an internal combustion engine having such an exhaust gas aftertreatment system, the exhaust gas from the internal combustion engine is heated up by the burner in order to heat up the second exhaust gas aftertreatment component for the selective, catalytic reduction of nitrogen oxides.