Internally Insulated Gas Manifold

The present invention relates to a gas manifold of an engine and more particularly to an exhaust gas manifold of a turbocharged engine.

In the art of gas manifolds, particularly gas manifold of an exhaust gas manifold of an internal combustion engine, it is important that the manifold be sized to optimum values to correspond to the demand characteristics of the engine. With the advent of turbo charged engines, the exhaust gases were used for heating purposes.

In the operation of a diesel engine, particularly a turbo charged diesel engine utilized in marine environments, it is desirable that the outer surface of the manifold be maintained below recommended maximum temperatures and that exhaust gas and heat be retained during operation. Further, the manifold must be compact owing to the limited space available on most marine vessels. Further, it is desirable that the outer surface of the manifold be abrasive resistant and free from external insulating elements.

The present invention is directed to overcome one or more of the problems as set forth above.

In one aspect of the invention, an exhaust gas manifold of an engine has a liner, a housing and an insulating element. The liner has at least one inlet and an outlet. The housing has at least one inlet, an outlet, and an outer surface. The housing is generally mateable about the liner and define an annulus between the housing and liner. The outer surface of the housing is free of insulation. The insulating element is positioned about the liner within the annulus. The insulating element is quilted and has a ceramic fiber encased within fiberglass.

FIG. 1 ms a perspective view of the manifold of this invention;

FIG. 2 ms a perspective view of the manifold with a portion of the housing removed;

FIG. 3 ms a partial view of the manifold showing the liner within the housing;

FIG. 4 ms a view of the bellows of the manifold;

FIG. 5 ms an enlarged sectioned view of the bellows of the manifold; and

FIG. 6 is a diagrammatic view showing the fiberglass and ceramic fiber of the manifold.

Referring to FIGS. 1-3, a gas manifold 2 of an engine 4 has a liner 6, a housing 8, and an insulating element 10. The liner 6 has at least one inlet 12 and an outlet 14. The housing 8 has at least one inlet 16, an outlet 18, and a outer surface 20.

Referring to FIG. 3, the housing 16 is generally mateable with and about the liner 6 and defines an annulus 22 between the housing 8 and liner 6. The insulating element 10 is positioned about the liner 6 within the annulus 22. The liner 6 has an outer surface 24 and the insulating element 10 covers substantially the entire outer surface 24 of the liner 6. The insulating element 10 of this invention provides sufficient insulation to the maintain the outer surface 20 of the housing 8 at an acceptable temperature below about 400 degrees F. during operation of the engine 4. Therefore, the outer surface 20 of the housing 8 of the manifold 2 of this invention is free of insulation.

The insulating element 10 is quilted and has a ceramic fiber 26 encased within fiberglass 28. The ceramic fiber 26 of the insulating element 10 is one of alumino-silicate, mineral wool and refractory ceramic fibers, preferably alumino-silicate, and more preferably substantially shot free alumino-silicate. The insulating element can be contained in a metal foil to aid in assembly.

Referring to FIG. 6, the quilting of the fiberglass 28 defines separate pockets 30,31 of ceramic fiber 26. The pockets 30,31 have pocket dimensions in the range of about 0.5 inches in length to about 10 inches in length and about 0.5 inches in width to about 10 inches in width. Preferably the dimensions of the pockets 30,31 are about 1 inch in length and about 1 inch in width.

Owing to the excellent insulating properties of the insulating element 10 of the construction of this invention, the insulating element 10 has a thickness in the range of about 0.25 inch to about 1 inch, more preferably about 0.325 inch, and at least having a thickness less than about 0.5 inch.

Referring to FIG. 4, the liner 6 and housing 8 are formed of a plurality of mating pieces and includes bellows 36 extending about and covering the mating portions of the liner pieces. By this construction, a manifold 2 can be constructed to provide multiple gas inlets.

Referring to FIG. 5, the mating pieces of the liner and housing are constructed to telescopically engage respective portions. The bellows 36 has first and second end portion 38,40, is formed of metal, and the first and second bellows end portions 38,40 are welded to and extend about respective telescopically engaged liner pieces. By this construction, the bellows 36 and their welds form expansion joints with gas tight seals between the liner pieces, which is most necessary for manifolds expected for marine usage.

Referring to FIG. 3, the liner inlet 12 and the housing inlet 16 each have mateable taper shoulders 32,34 contacting one another. In the installed position of the liner 6 within the housing 8, the liner inlet 12 extends outwardly from the housing inlet 16. Means such as bolts 42 are provided for connecting the manifold 2 to the engine.

The liner inlet 12 includes an annular groove 44 with a seal ring 46 disposed in the groove. The liner inlet 12 is of dimensions sufficient that at the installed position of the manifold 2 on the engine 4, the liner inlet portion is in forcible contact with the engine 4 and the housing inlet 16 is spaced from the engine 4.

The fiberglass 28 of the insulating element of this invention is preferably fiberglass cloth and more preferably is bidirectional fiberglass cloth as is well known in the art.

The liner 6 of this invention is formed of metal or ceramic material, preferably stainless steel. The housing 8 of this invention is preferably formed of metal, preferably cast iron. The housing 8 can be cast about a core formed of the liner 6 and the insulating element 10. Other materials suitable for the housing are aluminum and organic plastic. The liner 6 is preferably a thin walled vacuum cast liner.

The manifold of this invention is free from external insulating material or water cooling jackets, yet is capable of maintaining the temperature of the outer surface 20 of the housing 8 within acceptable temperatures during operation of the engine.

The manifold of this invention is of simple construction, compact, adapts itself to flexibility in construction and is solely internally insulated and thereby provides increased durability. The insulating element is thin and thereby conveniently adapts itself for use where engine space is severely limited, as for example in most marine applications. By providing a manifold having improved insulating characteristics, the manifold is particularly adapted for use in turbo charged engines where transfer of heat to the turbocharger improves efficiency.

Other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims.