A catalytic converter is provided with: an inlet-side diffuser part; an outlet-side diffuser part; a case including an upstream-side cylindrical part and a downstream-side cylindrical part; an inner liner provided in the upstream-side cylindrical part; a first catalyst retained inside the inner liner; and a second catalyst retained inside the downstream-side cylindrical part. An end face of the second catalyst faces a peripheral surface of the inner liner. An annular flow path is provided between the upstream-side cylindrical part and the inner liner, and the first catalyst is insulated from heat by the annular flow path. A part of exhaust flows into the second catalyst via the annular flow path.

A compact muffler (40) for an engine exhaust system, which is particularly applicable for use with small, reciprocating piston two-stroke engines of the type used on unmanned aerial vehicles (UAVs). The compact muffler (40) comprises an exhaust gas flow path (67) between an inlet (61) and an outlet (63). The exhaust gas flow path (67) comprises a plurality of adjacent flow passages (65), wherein at least two of the adjacent flow passages (65) are fluidly connected in series to enable the flow of exhaust gas from one to the other along the flow path (67). The adjacent flow passages (65) are configured for fluid flow therealong in opposed directions. A bypass passage (70) is provided between the two adjacent flow passages (65) for further communication between the two flow passages and to promote an equalisation of fluid pressure within the two adjacent passages (65). A UAV having an internal combustion engine (31) fitted with an exhaust system comprising the compact muffler (40) is also disclosed.

A method for manufacturing a vehicle muffler includes: forming a tubular body (6; 91, 92) from a nonwoven fabric (2; 2A, 2B) composed of inorganic fibers (11) each being in a filament form; inserting and installing the tubular body (6) as a sound-absorbing material into a space (S) between an inner pipe (72; 81) and an outer pipe (71; 821, 822) of an inner-outer double pipe constituting a vehicle muffler. The tubular body (6) may be obtained by applying a binder (3) to one surface (2a) of the nonwoven fabric (2), then rolling the nonwoven fabric (2) into a tubular shape with the surface (2a) having the binder (3) applied thereto facing inward, infiltrating additional binder (3) into an outer peripheral surface of the tubular-shaped nonwoven fabric (2), and then heating the tubular-shaped nonwoven fabric (2) to a predetermined temperature to harden the binder (3).

An internal combustion engine emissions reduction system in which a emissions passing through a second catalyst element having a second catalyst function are mixed with emissions passing through a first catalyst element having a first catalyst function.

Disclosed is a silencer for fuel cell vehicles. The silencer for fuel cell vehicles includes a housing having an inlet configured to receive air and hydrogen flowing into the housing therethrough, an outlet, and a condensation water drain hole configured to discharge condensation water to the outside therethrough, a distribution plate disposed in the housing and having distribution holes to distribute air and hydrogen flowing into the housing, a rotary plate disposed in the housing closer to the outlet than the distribution plate, a motor connected to the rotary plate to rotate the rotary plate, and an anti-freezing unit extending from one end of the rotary plate to the condensation water drain hole.

A method filtering exhaust gas may include attaching an exhaust tube to an engine at an exhaust gas inlet of the exhaust tube. The method may also include filling an outer tube of the exhaust tube with a liquid. The method may further include filtering the exhaust gas by passing the exhaust gas through an inner gas distributor disposed inside the outer tube, and through a plurality of holes of the inner gas distributor into the liquid of the outer tube. In addition, the method may include expelling filtered exhaust gas through an exhaust gas outlet of the exhaust tube.

A decomposition chamber for an aftertreatment system includes: a body comprising: an inlet configured to receive exhaust gas, an outlet configured to expel the exhaust gas, a thermal management chamber in fluid communication with the inlet, the thermal management chamber configured to receive an exhaust gas first portion from the inlet, an exhaust assist chamber in fluid communication with the inlet, the exhaust assist chamber configured to receive an exhaust gas second portion from the inlet, and a main flow chamber in fluid communication with the inlet, the main flow chamber configured to receive an exhaust gas third portion from the inlet, receive the exhaust gas first portion from the thermal management chamber, and receive the exhaust gas second portion from the exhaust assist chamber.

A decomposition chamber for an aftertreatment system includes: a body including: an inlet configured to receive exhaust gas; an outlet configured to expel the exhaust gas, a thermal management chamber in fluid communication with the inlet, the thermal management chamber configured to receive a first portion of the exhaust gas from the inlet, and a main flow chamber in fluid communication with the inlet, the main flow chamber configured to receive a second portion of the exhaust gas from the inlet and to receive the first portion of the exhaust gas from the thermal management chamber; and a diffuser positioned within the main flow chamber, the diffuser including: a diffuser inlet portion including a plurality of diffuser perforations, the diffuser inlet portion configured to receive the exhaust gas from the main flow chamber, and a diffuser flange portion configured to receive the exhaust gas from the diffuser inlet portion and provide the exhaust gas to the outlet.

An exhaust gas after-treatment mixing device comprises a casing, a mixing pipe located in the casing and a partition plate separating the casing into an upstream space and a downstream space. The mixing pipe comprises a first pipe portion located in the upstream space and a second pipe portion located in the downstream space. The first pipe portion is provided with at least two first openings located on two sides of the first pipe portion, respectively. A shielding plate shields an upstream portion of at least one of the first openings. The shielding plate is shaped and positioned within the casing to urge exhaust gas flowing through the upstream space away from the first end of the mixing pipe and around the shielding plate prior to entering the first openings.

In an exhaust gas processing device, an air-fuel ratio sensor is provided such that a measuring portion is located in a region surrounded by a downstream-side end surface of a TWC, an upstream-side end surface of a GPF, and an inner wall surface of a case against which the exhaust gas G that has passed through the TWC flows, that is the region a region on the GPF side of the center of the TWC.