Exhaust Mechanism

Abstract

An exhaust mechanism includes: an exhaust pipe configured to circulate exhaust gas from an engine; a first outer pipe disposed along the exhaust pipe on an outer periphery of the exhaust pipe; a second outer pipe disposed along the first outer pipe on an outer periphery of the first outer pipe; a pair of intermediate members disposed on the outer periphery of the exhaust pipe, fixed to respective inner peripheral surfaces of a first end portion and a second end portion of the first outer pipe, and being lower in thermal conductivity than the exhaust pipe. A vacuum layer is provided between the first outer pipe and the second outer pipe. At least one of the intermediate members is configured to slide in an axial direction of the exhaust pipe.

Description

INCORPORATION BY REFERENCE[0001]The disclosure of Japanese Patent Application No. 2016-251559 filed on Dec. 26, 2016 including the specification, drawings and abstract is incorporated herein by reference in its entirety.BACKGROUND1. Technical Field[0002]The disclosure relates to an exhaust mechanism.2. Description of Related Art[0003]Japanese Unexamined Patent Application Publication No. 11-36856 (JP 11-36856 A) discloses a structure in which an exhaust pipe between a catalytic converter and an exhaust manifold of an engine is configured as a vacuum double pipe that has an outer pipe and an inner pipe and a part of the inner pipe takes the form of a bellows pipe.SUMMARY[0004]In the structure disclosed in JP 11-36856 A, a decline in the temperature of the exhaust gas that circulates through the inner pipe is suppressed by the heat insulation effect of a vacuum layer between the outer pipe and the inner pipe. In the structure disclosed in JP 11-36856 A, the heat insulation effect of t...

AI Technical Summary

Benefits of technology

The patent describes an exhaust pipe mechanism that prevents the temperature of exhaust gas from decreasing in the ends of the outer pipes due to heat transfer. The mechanism includes a vacuum layer between the outer pipes, which helps to insulate and reduce heat transfer. The use of intermediate members with lower thermal conductivity than the outer pipes also helps to suppress heat transfer and maintain the temperature of the exhaust gas. Additionally, the mechanism includes layers of low-permeability materials to prevent the permeation of hydrogen from the atmosphere into the vacuum layer, which could cause a rise in pressure and compromise the heat insulation effect of the vacuum layer. Overall, this mechanism effectively prevents the temperature of exhaust gas from decreasing in the outer pipes and maintains the efficiency of the exhaust system.

Problems solved by technology

Once the condensed water is generated, the flow path area of the exhaust pipe decreases due to the accumulation of the condensed water, and then an increase in flow resistance and a decline in engine output arise.

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