An electric gas flow heater has a grid-like heating element through which exhaust gas can flow axially, and which forms an electrical resistance heating. The grid-like heating element includes radially successive layers of band-like material, wherein the layers, in an axial view of the heating element, are bent in an undulating manner and include valleys and peaks. The layers that are located between the radially outermost layer and the radially innermost layer are attached by their peaks and valleys to the respectively radially adjacent layer, so that flow-through openings are formed between the layers. The wavelengths of the layers are increasing radially outwards.

An exhaust gas system for an internal combustion engine includes at least one component which delimits an exhaust gas flow volume via an outer wall and, on an inner side of the outer wall which faces the exhaust gas flow volume, supports at least one shielding element. An intermediate space is formed between the outer wall and the shielding element. At least one connecting molding on the shielding element is directed toward the outer wall and is connected fixedly to the outer wall.

An exhaust gas cleaning system includes a particle filter device comprising a casing, plural hollow ceramic filter rods arranged at least partly inside a gas passage of the casing, and a gas inlet and gas outlet. The particle filter device guides exhaust gas from the gas inlet, through the gas passage and to the gas outlet. The particle filter device further comprises a perforated plate extending at least partly along the filter rods and partly blocking an exhaust gas flow path from the gas inlet to the gas passage. The perforated plate defines openings allowing exhaust gas to flow into the gas passage. The filter rods are gas permeable to allow exhaust gas to penetrate, during filtration, a respective wall of the filter rods and flow into the filter rods. A respective open upper end of the filter rods communicates with the gas outlet so exhaust gas leaves the casing.

A multi-pass catalytic converter can divide a catalyst block into several catalytic volumes and enable the exhaust gas to flow through each volume in two or more passes consecutively. As the exhaust gas in an early pass can emit sensible thermal energy and chemical reaction energy to preheat the remaining catalytic volumes via conductive heat transfer, it can shorten the catalyst light-off time for the later passes and the whole catalyst block. By recouping the previously lost dissipating heat from the early catalytic volume, the present disclosure can significantly reduce the catalyst light-off time and emission concentration. Furthermore, one or more mixing chambers can be utilized to thoroughly mix the exhaust gas.

An exhaust gas/reactant mixing arrangement is for an exhaust system of an internal combustion engine for mixing exhaust gas and reactant. The mixing arrangement includes an exhaust gas guide housing extending in the direction of a housing longitudinal axis and a housing wall. The housing wall surrounds and defines an exhaust gas duct accommodating a flow of exhaust gas. A mixing zone is formed between an upstream end wall and a downstream end wall arranged downstream of the upstream end wall. The mixing zone includes a first chamber and a second chamber as well as a reactant dispensing unit carried on the exhaust gas guide housing for dispensing reactant into the first chamber in a reactant main dispensing direction oriented substantially along a reactant dispensing line.

An after treatment system (ATS) for a vehicle includes, fluidly connected in series, an inlet, a urea mixer and an outlet. The inlet is fluidly connected to an output of an engine of the vehicle and the outlet is fluidly connected to an outlet tube of the vehicle. The urea mixer is provided with a dosing module, an inner element and an outer element. The inner element is configured such that a first flow of exhaust gas flow flowing from the inlet into the urea mixer flows into an first volume defined by the inner element. The outer element is configured such that a second flow flows in a volume defined between inner element and outer element, wherein the first and second flows rejoin together in a mixing chamber fluidly connected to the volume and to the first volume downstream with respect inner and outer elements.

A vehicle exhaust gas purification system and a control method thereof that may effectively remove nitrogen oxides in an exhaust gas even in a cold state, which is the initial stage of an engine starting, is disclosed. A control method of an exhaust gas purification system of a vehicle may include: a step of performing a rich control for controlling a concentration of non-combusted fuel contained in the exhaust gas flowing into the housing to be a rich fuel directly after the starting of the engine; a step of performing a lean control for controlling the concentration of the non-combusted fuel contained in the exhaust gas flowing into the housing to be a lean fuel; a step of determining whether a temperature of the exhaust gas flowing into the housing is a predetermined temperature or more; and a step of performing a normal control for controlling the concentration of the non-combusted fuel contained in the exhaust gas flowing into the housing so that a lean fuel and a rich fuel are periodically repeated with a regular interval.

A mixer assembly unit, for an exhaust system exhaust gas treatment unit of an internal combustion engine, mixes exhaust gas discharged by the internal combustion engine with reactant. A mixing section (12), downstream in relation to a reactant release device (14), mixes exhaust gas, flowing in an exhaust gas flow direction, with reactant. The mixing section includes a core flow duct (34), extending in a direction of a mixing section longitudinal axis (L), through which a first exhaust gas partial stream (T1) flows. A second exhaust gas partial stream (T2) flows through a jacket flow duct (36) surrounding the core flow duct and separated from the core flow duct by an inner wall (30). The reactant release device releases reactant into the core flow duct or/and into the first exhaust gas partial stream. A mixer (38) is provided at an upstream end area (22) of the mixing section.

An exhaust gas control system according to the present disclosure includes: a first exhaust gas control catalyst layer that controls an exhaust gas emitted from an internal combustion engine; and a second exhaust gas control catalyst layer that further controls the exhaust gas that has been controlled by the first exhaust gas control catalyst layer. The second exhaust gas control catalyst layer contains an oxygen storage material. The ratio of the amount (mmol—CO.sub.2/m.sup.2) of base points per specific surface area (m.sup.2/g) of the oxygen storage material to the specific surface area is equal to or less than 4.50×10.sup.−5.

A heater may include: a conductive ceramic cylinder tube in which cell-arrays are concentrically arranged, each cell-array including cells which are arranged in a circumferential direction of the ceramic cylinder tube; an inner electrode electrically coupled to an inner wall portion of the ceramic cylinder tube; and an outer electrode electrically coupled to an outer wall portion of the ceramic cylinder tube. Non-linear portions are radially arranged in the ceramic cylinder tube, each non-linear portion extending in a radial direction of the ceramic cylinder tube while having a plurality of bends or curves between the inner wall portion and outer wall portion of the ceramic cylinder tube. The inner and outer electrodes are provided such that current flows radially at least via said non-linear portions between the inner and outer electrodes.