Methods and systems are provided for improving catalyst temperature control while reducing oxygen saturation. Secondary air is injected at a location downstream of the catalyst during selected conditions. A mixing valve position is coordinated with the air injection to improve local turbulence and thereby enhance air and fuel mixing in the exhaust passage, in at least one arrangement.

Methods and systems are provided for improving catalyst temperature control while reducing oxygen saturation. Secondary air is injected at a location downstream of the catalyst during selected conditions. A mixing valve position is coordinated with the air injection to improve local turbulence and thereby enhance air and fuel mixing in the exhaust passage, in at least one example.

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.

Aspects of the present invention relate to a valve seat (20) for a poppet valve of an internal combustion engine, wherein the poppet valve comprises a head and a stem behind the head, the valve seat comprising: an aperture (21) configured to form a seal with the head of the poppet valve when the poppet valve is in a closed position; and a peripheral body (22) defining, at least in part, one or more ports (23) shaped like e.g. grooves and sized to enable injection of liquid or gas from a cylinder head of the internal combustion engine into a gas stream behind the head of the poppet valve.

A system includes a system includes an exhaust section which receives an exhaust flow of a gas turbine, where the exhaust section includes a catalyst assembly. The system includes an exhaust duct coupled to the diffuser section upstream of the catalyst assembly, where the exhaust duct extracts a return portion of the exhaust flow. The system includes a filter house coupled to the exhaust duct, where the filter house is receives a combined flow of an ambient air flow and the return portion. The system includes a return conduit coupled to the filter house and the exhaust section, where the return conduit is coupled to the exhaust section upstream of the exhaust duct. The return conduit directs the combined flow to the exhaust section, and the catalyst assembly receives a mixed flow including the exhaust flow and the combined flow.

The present disclosure relates to internal combustion engines. The teachings thereof may include monitoring a secondary air system with which secondary air is introduced into exhaust of the internal combustion engine wherein individual cylinders of the internal combustion engine are associated with one of at least two cylinder banks and a separate exhaust duct is associated with each cylinder bank. The methods may include delivering secondary air with a compression arrangement via a common secondary air line divided into a number of individual secondary air sublines corresponding to the number of exhaust ducts at a branching point downstream of the compression arrangement; controlling the secondary air to simultaneously enable or inhibit the flow to the individual secondary air sublines; detecting values for the pressure downstream of the compression arrangement and upstream of the branching point; detecting pulsations of a pressure in each cylinder bank when the compression arrangement is activated and the throughflow control arrangement set into the open state; summing the pulsations; comparing each of summed-up values with threshold values; and if the respective threshold value is exceeded, identifying a fault in the throughflow control arrangement.

In order to surely remove deposits attached on the inner wall of an exhaust gas pipe, an exhaust gas measurement system that measures components contained in the exhaust gas of an internal combustion engine is adapted to include an exhaust gas piping member into which the exhaust gas is introduced; a purge gas supply mechanism adapted to supply purge gas to the exhaust gas piping member; a heating mechanism adapted to heat the exhaust gas piping member; and a control mechanism adapted to, after the heating mechanism has heated the exhaust gas piping member or the exhaust gas flowing through the exhaust gas piping member to a predetermined temperature, control the purge gas supply mechanism to start supplying the purge gas.

An exhaust purification system for purifying exhaust gas from a combustion engine comprising: an exhaust pipe (10) for the supply of exhaust gas; a pre-chamber (12) for receiving a flow of exhaust gas via a supply pipe (14); a supply valve (16) for controlling a flow of exhaust gas into the pre-chamber; at least one mixing chamber (18), in fluid connection with the pre-chamber for receiving the exhaust gas via the pre-chamber; an ionizing equipment (20) configured to ionize air, connected to the mixing chamber (18) so that ionized air is fed into the mixing chamber and is mixed with the exhaust gas; wherein the supply valve (16) is configured to be controlled based on a flow velocity of exhaust gas in the exhaust pipe (10).

A system includes a system includes an exhaust section which receives an exhaust flow of a gas turbine, where the exhaust section includes a catalyst assembly. The system includes an exhaust duct coupled to the diffuser section upstream of the catalyst assembly, where the exhaust duct extracts a return portion of the exhaust flow. The system includes a filter house coupled to the exhaust duct, where the filter house is receives a combined flow of an ambient air flow and the return portion. The system includes a return conduit coupled to the filter house and the exhaust section, where the return conduit is coupled to the exhaust section upstream of the exhaust duct. The return conduit directs the combined flow to the exhaust section, and the catalyst assembly receives a mixed flow including the exhaust flow and the combined flow.

A system for generating electricity with reduced or negative carbon emissions. The system includes a power plant section having an electricity generating unit having an input coupled to a hydrocarbon fuel supply and an energy exchange path. The system also includes a direct air capture (DAC) section having a CO.sub.2 adsorption device having a CO.sub.2 adsorbent material and a ventilator electrically coupled to the electricity generating unit, the ventilator directing air flow through the CO.sub.2 adsorption device in a carbon capture mode, wherein the CO.sub.2 adsorption device is coupled to and in energy communication with the energy exchange path for releasing adsorbed CO.sub.2 in a carbon release mode.