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 muffler for receiving exhaust gas from a combustion engine comprises a shell, first and second inlet pipes each having outlets providing exhaust gas to a mixing chamber within the shell, a first chamber and a second chamber positioned within the shell and a pair of communication pipes each including an inlet receiving exhaust gas from the mixing chamber. Each communication pipe includes an outlet providing exhaust to the second chamber. Each of the communication pipes further includes a Helmholtz opening positioned downstream of the mixing chamber. The Helmholtz openings are open to the first chamber.

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 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.

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

An SCR system includes at least one catalyst, and an intake conduit. The intake conduit includes an intake conduit first sidewall, at least a portion of which defines a first curvature. An intake conduit second sidewall is coupled to the intake conduit first sidewall so as to define the intake conduit. A catalyst is fluidly coupled to the intake conduit through the intake conduit second sidewall. The intake conduit second sidewall is inclined at a first angle with respect to a longitudinal axis of the SCR system, such that an intake conduit second end cross-section of the intake conduit is smaller than an intake conduit first end cross-section. An intake conduit third sidewall is positioned at the intake conduit second end. The intake conduit is structured to produce an even flow split of the exhaust gas through the intake conduit internal volume towards the catalyst.

Systems for and methods of evacuating air from a muffler while it is being filled with a fibrous material are disclosed.

An SCR system includes at least one catalyst, and an intake conduit. The intake conduit includes an intake conduit first sidewall, at least a portion of which defines a first curvature. An intake conduit second sidewall is coupled to the intake conduit first sidewall so as to define the intake conduit. A catalyst is fluidly coupled to the intake conduit through the intake conduit second sidewall. The intake conduit second sidewall is inclined at a first angle with respect to a longitudinal axis of the SCR system, such that an intake conduit second end cross-section of the intake conduit is smaller than an intake conduit first end cross-section. An intake conduit third sidewall is positioned at the intake conduit second end. The intake conduit is structured to produce an even flow split of the exhaust gas through the intake conduit internal volume towards the catalyst.

Systems for and methods of evacuating air from a muffler while it is being filled with a fibrous material are disclosed.