An internal combustion engine comprises: an exhaust purification catalyst; a downstream side air-fuel ratio sensor which is arranged at a downstream side of the exhaust purification catalyst; and an air-fuel ratio control system which performs feedback control so that the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst becomes a target air-fuel ratio. The air-fuel ratio control system switches the target air-fuel ratio to a lean set air-fuel ratio when the air-fuel ratio detected by the downstream side air-fuel ratio sensor becomes a rich judged air-fuel ratio or less; changes the target air-fuel ratio to a slight lean set air-fuel ratio after switching the target air-fuel ratio to the lean set air-fuel ratio and before an estimated value of the oxygen storage amount of the exhaust purification catalyst becomes a switching reference storage amount or more; and switches the target air-fuel ratio to a rich air-fuel ratio when the estimated value of the oxygen storage amount of the exhaust purification catalyst becomes the switching reference storage amount or more.

An exhaust system including: an exhaust pipe including a straight portion, and a bent portion that is bent and extends from a downstream end of the straight portion; a muffler provided on a downstream side of the exhaust pipe; and a reinforcing member, wherein: the straight portion of the exhaust pipe is connected with an upstream end of the muffler through the bent portion; and the reinforcing member is provided so as to extend across a downstream end portion of the straight portion, and an upstream end portion of the muffler.

A work vehicle includes an engine, a post-processing device, and a cooling fan. The engine is mounted on a front portion of a travelling machine body. The post-processing device purifies exhaust gas of the engine. The cooling fan water-cools the engine. The cooling fan is located in front of the engine. The cooling fan, the engine, and the post-processing device are covered with a hood. The hood includes a shield. The shield covers a lower section of the post-processing device and one side of the engine. The shield is a perforated plate including a plurality of holes.

A work vehicle includes an engine, a post-processing device, and a cooling fan. The engine is mounted on a front portion of a travelling machine body. The post-processing device purifies exhaust gas of the engine. The cooling fan water-cools the engine. The cooling fan is located in front of the engine. The cooling fan, the engine, and the post-processing device are covered with a hood. The hood includes a shield. The shield covers a lower section of the post-processing device and one side of the engine. The shield is a perforated plate including a plurality of holes.

Systems are provided for an exhaust gas aftertreatment device, in particular in a motor vehicle, having a catalyst accommodated in a housing which, along its length, has a first end section, a catalyst section, and a connecting section. The housing further comprising a particulate filter located downstream of the catalyst.

An exhaust system for a combustion engine includes first and second catalytic converters arranged downstream of the combustion engine in a flow direction of exhaust gas. First and second exhaust pipes extend from the combustion engine to the first and second catalytic converters, respectively, with a first valve disposed in the first exhaust pipe, and a second valve disposed in the second exhaust pipe. The first and second valves operate such that in the presence of an exhaust temperature which is equal to or less than a limit value, at least the first valve opens to allow exhaust gas from the combustion engine to flow through the first catalytic converter, and that the first valve closes and the second valve opens, when the exhaust temperature is greater than the limit value to thereby allow exhaust gas from the combustion engine to flow through the second catalytic converter.

Methods and systems are provided for exhaust heat recovery and hydrocarbon trapping at an exhaust bypass assembly. Exhaust gas may flow in both directions through an exhaust bypass passage and each of a HC trap and a heat exchanger coupled to the bypass passage. The HC trap may be purged with the hot exhaust and heat from the exhaust may be recovered at the heat exchanger.

An exhaust gas aftertreatment system includes: a first sensor configured to measure a parameter in the exhaust gas aftertreatment system; a second sensor configured to measure the parameter in the exhaust gas aftertreatment system, the second sensor disposed proximate the first sensor; and at least one controller configured to simultaneously receive sensor values from the first sensor and receive sensor values from the second sensor.

The disclosure relates to a fuel supply device for supplying a fuel to an internal combustion engine comprising: a fuel store for storing a primary fuel; and at least two parallel fuel supply paths that are connected to the fuel store, on the one hand, and to the internal combustion engine, on the other hand, wherein the primary fuel can be supplied from the fuel store to the internal combustion engine by means of the first fuel supply path for the purpose of combustion, and the second fuel supply path has at least one reforming device that reforms the primary fuel supplied from the fuel tank into a secondary fuel, and to supply at least a portion of the produced secondary fuel to the internal combustion engine for the purpose of combustion.

The present invention relates to the use of different regeneration strategies for nitrogen oxide storage catalysts (NOx storage catalyst, LNT or NSC), depending on the exhaust gas temperatures, to reduce in the total exhaust gas the greenhouse gas N.sub.2O (nitrous oxide) that is produced as a secondary emission during the regeneration of the storage catalyst. If the exhaust gas temperature is below 275° C.-290° C., regeneration takes place using a strategy with short pulses of around 2 seconds and λ Lambda 0.95 rich.