An exhaust pipe structure for an in-line four-cylinder internal combustion engine includes: an in-line four-cylinder internal combustion engine; four exhaust pipes connected with respective exhaust ports in respective cylinders of the internal combustion engine; and a converging exhaust pipe connected with a converging portion at which downstream ends of all the exhaust pipes converge. In this exhaust pipe structure, the exhaust pipes are each configured as a dual pipe including an outer pipe and an inner pipe disposed inside the outer pipe. At the converging portion, the four exhaust pipes are arrayed linearly in parallel with each other, and the outer pipes of adjacent ones of the exhaust pipes are directly welded with each other at the downstream ends.

A manifold system for an internal combustion engine, having a housing, which is designed as a collecting manifold and which has two inlet openings and an outlet opening for the flow connection of two outlets of an internal combustion engine to an exhaust system and at most two connection openings provided on the housing for connecting a double-shell inner air-gap-insulated manifold. An exhaust system is developed in such a way that, at the same time, the tone of the exhaust gas noise and thus of the exhaust system is optimized over a plurality of important rotational speed ranges of the internal combustion engine by a modular assembly. For this purpose, at least one separate inner air-gap-insulated manifold having a connection opening, an inlet opening, and an outlet opening is provided, which is connected to the housing by the outlet opening, and at least one separate outer air-gap-insulated manifold having an inlet opening and an outlet opening is connected to the connection opening of the inner air-gap-insulated manifold. All air-gap-insulated manifolds are completely formed of sheet metal, and each air-gap-insulated manifold has a separate one- or multi-part inner shell and a one- or multi-part separate outer shell. All inner air-gap-insulated manifolds are structurally or geometrically identical and all outer air-gap-insulated manifolds are structurally or geometrically identical, wherein the inner air-gap-insulated manifolds are not structurally identical and not geometrically identical to the outer air-gap-insulated manifolds.

An exhaust enclosure system may include an inner insulation assembly circumferentially surrounding an outlet pipe of an engine exhaust manifold. The inner insulation assembly may be in direct contact with the exhaust manifold. The exhaust enclosure system may include a cover enclosing the inner insulation assembly. The cover may be physically separated from the inner insulation assembly by a circumferential air gap disposed between the inner insulation assembly and the cover.

The heat insulation structure for a component of an exhaust system of a piston engine is arrangeable around the component such that an air space is formed between the component and the heat insulation structure, and includes an outer shell layer a middle shell layer that is arranged inside the outer shell layer, and a first inner shell layer that is arranged inside the middle shell layer. A first air gap is arranged between the outer shell layer and the middle shell layer, a first insulation layer is arranged between the middle shell layer and the first inner shell layer, and the outer shell layer is provided with venting apertures for natural ventilation of the first air gap.

An exhaust system with a multipiece heat shield for a work vehicle includes a first shield part and a second shield part. The first shield part surrounds an aftertreatment unit for aftertreating exhaust gases. The first shield part extends in an axial direction. The second shield part surrounds an exhaust tailpipe with radial spacing between the second shield part and the exhaust tailpipe. The second shield extends in the axial direction from the first shield part, wherein a radial gap between the first and second shield parts is sealed by a seal. In a starting position, the seal has two free ends arranged in the circumferential direction of the heat shield, which are arranged adjoining or overlapping one another in the circumferential direction when the seal is in a sealing position.

Provided is a shield in which a flexible member is interposed between two metal plates; still unfilled spaces that are not filled with the flexible member are secured, so that the shielding properties are improved by air layers. The shield 1A includes two metal plates 2, 3 disposed to face each other, and a plate-shaped flexible member 4 interposed between the two metal plates. Each of the two metal plates 2, 3 has a plurality of protrusion-depression structures. Gap-forming means is provided to form gaps of a width greater than the thickness of the flexible member 4 between the two metal plates 2, 3 when the flexible member 4 is interposed therebetween. Unfilled spaces (5) that are not filled with the flexible member 4 are provided between the two metal plates 2, 3.

An aftertreatment system can include a radiation shield for reducing and/or redirecting radiative thermal energy. The aftertreatment system can include a first housing, a second housing, a first aftertreatment component, and the radiation shield. The first aftertreatment component is positioned within one of a first interior volume of the first housing or a second interior volume of the second housing. The radiation shield includes an attachment portion and a thermal barrier portion. The attachment portion is coupled to an exterior of the first housing or the second housing. The thermal barrier portion is structured to divert radiative thermal energy in a second direction different than a source direction of the radiative thermal energy.

An exhaust system with a multipiece heat shield for a work vehicle includes a first shield part and a second shield part. The first shield part surrounds an aftertreatment unit for aftertreating exhaust gases. The first shield part extends in an axial direction. The second shield part surrounds an exhaust tailpipe with radial spacing between the second shield part and the exhaust tailpipe. The second shield extends in the axial direction from the first shield part, wherein a radial gap between the first and second shield parts is sealed by a seal.

A catalyst device includes a catalyst support, a tubular portion, which accommodates the catalyst support, a holding mat, which holds the catalyst support, an insulator provided over the outer circumferential surface of the tubular portion, and a heat insulating member arranged between the insulator and the tubular portion. The region of the outer circumferential surface of the tubular portion between the upstream end and the downstream end in the exhaust gas flowing direction is divided into two subregions arranged in a direction of the axis of the tubular portion. Of the two subregions, the subregion on the upstream side is defined as an upstream subregion, and the subregion on the downstream side is defined as a downstream subregion. The area that is covered with the heat insulating member in the downstream subregion is smaller than the area that is covered with the heat insulating member in the upstream subregion.

An exhaust structure is provided with an exhaust manifold, and a supercharger having a turbine housing. The turbine housing is provided with an inflow port interconnected with the exhaust manifold, a housing member in which a space for housing turbine blades is formed, and an inflow port in which an inflow passage communicating from the inflow port through the housing space is formed. A sensor mounting part is formed in the inflow port, and a throttle member is formed such that the width thereof in an aligning direction of cylinders gradually decreases from the inflow port toward the sensor mounting part. With this configuration, the accuracy of detecting the combustion state of the cylinders can be increased.