Technologies for producing an exhaust gas stream with controlled hydrocarbon species are disclosed. In some embodiments the technologies include an apparatus for producing an exhaust gas stream. The apparatus may include a burner for combusting primary fuel and produce an exhaust gas stream, and an exhaust pipe coupled to the burner to receive the exhaust gas stream. One or more supplemental fuel inlets may be coupled to the exhaust gas pipe for the addition of supplemental fuel to the exhaust gas stream. In embodiments, the speciation and total concentration of hydrocarbon compounds in the exhaust gas stream may be adjusted by controlling the relative amount of supplemental fuel added to the exhaust gas stream. Methods for producing an exhaust gas stream are also disclosed.

An exhaust gas aftertreatment system for an internal combustion engine has an exhaust system that can be connected to an outlet of the internal combustion engine. A three-way catalytic converter that is situated close to the engine and, downstream from the three-way catalytic converter that is situated close to the engine, a second catalytic converter and a particle reduction device are arranged in the direction in which an exhaust gas of the internal combustion engine flows through an exhaust gas channel of the exhaust system. A fuel injector is arranged on the exhaust gas channel so as to inject fuel downstream from the three-way catalytic converter that is situated close to the engine and upstream from the second catalytic converter, and the exhaust system comprises a secondary air system with which secondary air can be blown into the exhaust gas channel downstream from the three-way catalytic converter that is situated close to the engine and upstream from the second catalytic converter.

Methods and systems are provided for heating an exhaust particulate filter (PF) to enable filter generation. In one example, a method may include adjusting engine air fuel ratio and injecting secondary air flow upstream of the PF to increase PF temperature. The level of engine air fuel ratio adjustment and the amount of secondary air injection upstream of the PF may be adjusted to account for enrichment induced cooling at a three-way catalyst (TWC) positioned upstream of the PF.

A method for operating a petrol engine, in which air is introduced into an exhaust tract through which exhaust gas from the petrol engine can flow, bypassing the petrol engine, includes introducing the air into the exhaust tract at a point arranged downstream of a first three-way catalytic converter arranged in the exhaust tract and upstream of a second three-way catalytic converter arranged in the exhaust tract downstream of the first three-way catalytic converter, while the petrol engine is operated with a sub-stoichiometric combustion air ratio, where a desulphurization of the second three-way catalytic converter is effected.

A system for reducing emissions from an internal combustion engine includes a combustion chamber having an inlet and an outlet, a fuel delivery device for delivering fuel to the combustion chamber, and a control system for controlling a fuel to oxidizer ratio in the combustion chamber. A method of reducing emissions from an internal combustion engine includes the steps of: establishing a flow of oxygen-containing gas through a combustion chamber having an inlet and an outlet; introducing flow of fuel into the combustion chamber; igniting the fuel in the combustion chamber; operating an internal combustion engine to develop a stream of exhaust gas; introducing a flow of the exhaust gas into the combustion chamber; and controlling the flow of exhaust gas and the flow of fuel to minimize oxygen levels in exhaust gases downstream of the outlet.

An exhaust treatment device for a diesel engine includes a parked regeneration requirement notification component, and a parked regeneration start operation component, a regeneration process of a diesel particulate filter includes an automatic regeneration process and a parked regeneration process, the automatic regeneration process is automatically started when an estimation value of particulate material accumulated in the diesel particulate filter reaches a predetermined value, and the parked regeneration process is performed when first and second conditions are satisfied, the first condition being that a parked regeneration requirement notification component performs a notification of a parked regeneration requirement when a number of cancellations of the automatic regeneration process reaches a predetermined value or more, the second condition being that the parked regeneration start operation component is subjected to a start operation during a parked state in which an engine equipped machine is neither traveling nor working.

Technologies for producing an exhaust gas stream with controlled hydrocarbon species are disclosed. In some embodiments the technologies include an apparatus for producing an exhaust gas stream. The apparatus may include a burner for combusting primary fuel and produce an exhaust gas stream, and an exhaust pipe coupled to the burner to receive the exhaust gas stream. One or more supplemental fuel inlets may be coupled to the exhaust gas pipe for the addition of supplemental fuel to the exhaust gas stream. In embodiments, the speciation and total concentration of hydrocarbon compounds in the exhaust gas stream may be adjusted by controlling the relative amount of supplemental fuel added to the exhaust gas stream. Methods for producing an exhaust gas stream are also disclosed.

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 pipe for the exhaust tract of a combustion machine, which has an inlet opening for an air connection, is characterized by an inner pipe section which is surrounded by an outer pipe section in order to form an annular channel that is closed at one end and at the other end is open toward the inner volume of the exhaust pipe, wherein the inlet opening for the air connection opens into the outer pipe section. By means of such an exhaust pipe, advantageous mixing of air supplied via the air connection into the exhaust gas flowing within the exhaust pipe can be achieved with a simple design, which can be attributed in particular to the complete introduction of the air in combination with the flow direction that is present along the longitudinal axis of the annular channel and the exhaust pipe.

A method (200) for ascertaining an air volume provided by means of an electric air pump (134) in an exhaust system (120) of an internal combustion engine (110), including detecting at least one activation parameter (5) of the air pump and ascertaining (220) a provided air mass flow rate (8) on the basis of a calculation specification from the at least one activation parameter (5) by utilizing an inertia of the air pump (134) and/or an inertia of the air upstream and/or downstream from the air pump (134) and/or a differential pressure from upstream from the air pump to downstream from the air pump. In addition, a processing unit and a computer program for carrying out a method (200) of this type is provided.