D-shaped tube for header

Abstract

Disclosed is a water cooled exhaust assembly for use in association with an internal combustion engine in a marine environment. Inner and outer nested tubes are affixed to a mounting flange to form, in conjunction with an access port in the mounting flange, a cooling water flow channel to provide cooling of exhaust gases from the engine. The inner tube is formed with a flattened portion to produce a reduction in exhaust gas turbulence in the flow channel with a consequent increase in heat transfer capability.

Description

PRIORITY CLAIM [0001] This application claims the benefit of previously filed U.S. Provisional Patent Application entitled “D-SHAPED TUBE FOR HEADER,” assigned U.S. Ser. No. 60 / 721,762, filed Sep. 29, 2005, and which is incorporated herein by reference for all purposes.FIELD OF THE INVENTION [0002] The present subject matter relates to exhaust systems and, more particularly, to water cooled exhaust systems for marine applications. BACKGROUND OF THE INVENTION [0003] The incorporation of water cooling for exhaust systems for internal combustion engines has many advantages. While high temperature of the exhaust gases is desirable for high power output from the engine, high exhaust gas temperatures at the manifold place a high degree of stress on the manifold pipes. Moreover, under some conditions, hot combustion gases coming from an internal combustion engine may be combustible and potentially explosive. Thus, excess heat from the hot combustion gases must be continuously removed in or...

AI Technical Summary

Benefits of technology

[0014] In an exemplary configuration, an assembly of nested exhaust and cooling jacket pipes is provided in combination with an exhaust manifold attachment flange that simplifies coupling of both exhaust emissions and cooling water to the assembly.

[0016] In accordance with aspects of certain embodiments of the present subject matter, methodologies are provided to reduce the turbulence of the cooling water flow between the exhaust pipe and jacket pipe to improve heat transfer from the exhaust gases to the cooling water.

[0017] In accordance with further certain aspects of other embodiments of the present subject matter, methodologies have been developed to improve heat transfer to the cooling water by providing shaped correspondence between the walls of the nested exhaust pipe and jacket pipe to enhance the cooling water flow characteristics.

[0018] In one present exemplary embodiment, a water cooled exhaust assembly preferably comprises an outer tube portion, an inner tube portion having a generally free end thereof, and a mounting flange for supporting such assembly relative to an associated internal combustion engine. Additionally, there is provided at least one cooling water entrance port formed in the mounting flange, and at least one cooling water exit port formed in the outer tube portion. In such preferred exemplary embodiment, preferably the inner and outer tube portions are configured for the inner tube portion to pass exhaust gases from an associated internal combustion engine while a space is formed between the inner and outer tube portions for defining a cooling water channeling system in conjunction with the entrance and exit ports. Still further in such exemplary embodiment, preferably the inner and outer tube portions have predetermined shaped correspondence between the walls thereof, for reducing turbulence of the flow characteristics of cooling water passing therethrough, for improved heat transfer characteristics.

[0020] Another present exemplary water cooled exhaust system for internal combustion engines may preferably comprise an assembly of nested exhaust and cooling jacket pipes, and an exhaust manifold attachment flange, for simplified coupling of both exhaust emissions and cooling water to such assembly. In such assembly, preferably the nested pipes have a predetermined shape between the walls thereof, for improved heat transfer characteristics by reducing turbulence of the flow characteristics of cooling water passing therethrough, for more efficient heat transfer.

[0023] Yet another present exemplary embodiment relates to methodology, including for example methodology for improved heat transfer from exhaust gases of an internal combustion engine to cooling water in a water cooled exhaust system of the type having an assembly of nested pipes, such assembly having an inlet end, an outlet end, and respective relatively inner and outer pipes thereof, and configured to pass exhaust gases of the internal combustion engine through the relatively inner pipe thereof, and to permit cooling water to flow between an outer surface of such inner pipe and an inner surface of the relatively outer pipe thereof. Such improved methodology preferably includes providing predetermined shaped correspondence between the walls of the nested pipes to reduce the turbulence of the cooling water flow between the nested inner and outer pipes, which in turn improves heat transfer to the cooling water. Still further, per such present methodology, it may be included that providing the predetermined shaped correspondence comprises defining a relatively flattened area in said inner pipe. In certain present embodiments, such methodology of defining a relatively flattened area in such inner pipe may also include includes defining such relatively flattened area generally near an end of the inner pipe relatively adjacent to the assembly inlet end.

Problems solved by technology

While high temperature of the exhaust gases is desirable for high power output from the engine, high exhaust gas temperatures at the manifold place a high degree of stress on the manifold pipes.

Moreover, under some conditions, hot combustion gases coming from an internal combustion engine may be combustible and potentially explosive.

Excessively high temperatures can lead to premature failure of exhaust manifold assemblies, compromising the ability of the exhaust manifold assembly to remove the heat and exhaust gases from the engine and engine compartment.

Thus, relying on more sophisticated and possibly more expensive materials to handle the hot exhaust gases is not a preferred solution.

However the water flow is limited, a predetermined minimum flow of cooling water is maintained through the exhaust system, at least either at periodic intervals, or at a constant but lowered rate, to maintain cooling in the exhaust system on rubber components of the exhaust system.

While various implementations of a water cooled exhaust system exist, no design has emerged that generally encompasses all of the desired characteristics as hereafter presented in accordance with the subject technology.

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