An exhaust muffler includes a first muffler section having a tubular member made up of an inner pipe to which an exhaust pipe is connected and an outer pipe covering the inner pipe, and a connector connecting the tubular member and a second muffler section to each other, and the second muffler section having an outer shell, a first partition wall, a second partition wall, and a third partition wall. Exhaust gases delivered from the exhaust pipe are discharged from the first muffler section and the second muffler section out of the exhaust muffler. The second muffler section has a cross-sectional area larger than a cross-sectional area of the tubular member. The exhaust muffler includes a first expansion chamber, a second expansion chamber, and a third expansion chamber. The second muffler section includes a fluid communication pipe extending through the first partition wall and the second partition wall for leading exhaust gases from the first expansion chamber into the second expansion chamber, and an exhaust passage pipe held in fluid communication with the third expansion chamber and extending through the second partition and the third partition wall. The second partition wall has a fluid communication hole defined therein that provides fluid communication between the second expansion chamber and the third expansion chamber. There is thus provided an engine exhaust device capable of increasing a silencing capability by increasing the length of a route through which the exhaust gases flow while maintaining the length of the exhaust device.

The present disclosure describes methods for operating an EAS including a close coupled SCR unit, a downstream SCR unit, a diesel oxidation catalyst unit (DOC) and a diesel particulate filter (DPF). The methods utilize the close coupled SCR unit to manage NOx emissions from the EAS during regeneration of a diesel particulate filter (DPF).

An aftertreatment system for treating exhaust gases from an internal combustion engine includes, in series, a diesel oxidation catalyst (DOC), a diesel particular filter (DPF) downstream the DOC, and a primary selective catalyst reduction (SCR) catalyst downstream the DPF. A supplemental SCR catalyst is disposed upstream the DOC, DPF, and primary SCR catalyst to receive raw exhaust gases from the internal combustion engine. The supplemental SCR catalyst may conduct an SCR reaction on the raw exhaust gases until the supplemental SCR catalyst reaches a reaction temperature, at which time the supplemental SCR catalyst may conduct the SCR reaction.

In one aspect, a system is provided and includes an engine including an exhaust valve, an exhaust manifold downstream of the exhaust valve and a muffler downstream of the exhaust manifold. The system also includes a catalyst positioned downstream of the exhaust valve.

Provided is an exhaust system for an internal combustion engine comprising: a first exhaust conduit leading from a first exhaust bank of the engine to a first turbocharger turbine inlet arranged downstream of the first exhaust bank in the direction of travel of a first exhaust stream; a second exhaust conduit leading from a second exhaust bank of the engine to a second turbocharger turbine inlet arranged downstream of the second exhaust bank in the direction of travel of a second exhaust stream; an SCR catalyst arranged downstream of the first turbocharger turbine inlet and/or second turbocharger turbine inlet; and a reductant supply system comprising a distributor pipe and a reductant injector. The distributor pipe is configured to fluidly connect the first exhaust conduit to the second exhaust conduit upstream of the first turbocharger turbine inlet and second turbocharger turbine inlet, and the reductant injector is configured to supply a reductant to the distributor pipe.

This exhaust structure for a vehicle-mounted engine has an air intake channel 3 disposed on one side of an engine main body and an exhaust channel disposed on the other side thereof, the exhaust structure for the vehicle-mounted engine comprising: a turbine of a turbocharger disposed on the other side of the engine main body and connected to the exhaust channel; a first exhaust gas purification device connected to the exhaust channel downstream of the turbine; and a second exhaust gas purification device connected to the exhaust channel 4 downstream of the first exhaust gas purification device. The first exhaust gas purification device is disposed so as to be near the rear of the turbocharger, and the second exhaust gas purification device is disposed so as to be near a cylinder hock on the other side of the engine main body.

A three-way catalyst article is provided for the treatment of exhaust gas from a positive ignition engine, the catalyst article comprising: a substrate having a first layer provided thereon, wherein a second layer is provided on the first layer, wherein the first layer comprises a first metal and a first alumina, and wherein the second layer comprises a second metal and a second alumina, wherein either (i) the first metal is Pd and the second metal is Rh; or (ii) the first metal is Rh and the second metal is Pd; and wherein at least one of the first and second aluminas comprises theta alumina.

A system for the treatment of exhaust gases from an internal combustion engine with a combustion chamber includes an upstream DEF injector disposed to introduce DEF to the combustion chamber and a close-coupled SCR catalyst downstream of and in close-coupled relation to the internal combustion engine. Downstream of the close-coupled SCR catalyst may be a primary SCR catalyst and a primary DEF injector. The system may operate to reduce NO.sub.2 in the close-coupled SCR catalyst during low-load conditions of the internal combustion engine and reduce NO.sub.2 in the primary SCR catalyst during loaded conditions.

The invention relates to an exhaust gas aftertreatment system for an internal combustion engine comprising a first catalytic converter that has a first exhaust gas inlet to admit the exhaust gas into the first catalytic converter and has an exhaust gas outlet positioned on the opposite side, also comprising a second catalytic converter that is arranged downstream from the first catalytic converter and that is flow-connected to the first catalytic converter in order to allow the exhaust gas to pass from the first catalytic converter into the second catalytic converter and that likewise has a second exhaust gas inlet that is at a physical distance from the exhaust gas outlet of the first catalytic converter. The exhaust gas aftertreatment system also comprises a particulate filter that is arranged downstream from the second catalytic converter and that is flow-connected to the second catalytic converter in order to allow the exhaust gas to pass from the second catalytic converter into the particulate filter. A flow-around area is formed adjacent to an outer surface of the first catalytic converter in which the exhaust gas flows from the exhaust gas outlet to the second exhaust gas inlet into the second catalytic converter.

The present disclosure provides a muffler system that can effectively reduce exhaust noises. The muffler system includes an exhaust passage and a first muffler. The exhaust passage is configured to allow a flow of an exhaust gas. The first muffler is an expansion chamber muffler and disposed in the exhaust passage. The first muffler is situated upstream of a first position in a flow direction of the exhaust gas. The first position is located away from an upstream end of the exhaust passage by one third of an entire length of the exhaust passage.