Flexible Marine Engine Exhaust

Abstract

A flexible marine exhaust system which comprises a plurality of interchangeable conduit sections. The conduit sections may have different shapes. They may be interconnected in end-to-end relation so that an exhaust system having any desired configuration can be assembled.

Description

This invention relates to exhaust systems for marine engines and more particularly to an exhaust system which can be assembled on board in any desired configuration.

Exhaust systems for marine engines must provide for the escape of exhaust gases from the boat. A number of safety and performance requirements must be met by such systems. Thus, they must prevent exhaust gases or water from leaking into the boat. Because of the very high temperatures of the exhaust gases, the exhaust system must be cooled, preferably by sea water, so that damage to the exhaust system or injury to personnel is avoided.

Furthermore, the system should provide a means for mixing the overboard engine cooling water with the overboard exhaust gases at a point and in a manner which will prevent the burning of the hose connection normally made at this point while not creating excessive gas back pressure. Back pressure, which reduces the efficiency of the engine, occurs when the exhaust gases are discharged below the surface of the water. The back pressure may be of sufficient force to cause water to back up through the exhaust system and into the engine. Thus, water should be mixed with the exhaust gases at a location which provides adequate drainage away from the engine.

Typically, the foregoing requirements have been met by exhaust systems which comprise double wall conduits. The conduit defined by the inner wall is a gas passage through which exhaust gases are conducted. The outer wall defines a cooling water passage between itself and the inner wall. The problem resulting from back pressure has been minimized to a large extent by the use of risers in the exhaust system. Typically, the risers comprise inverted generally U-shaped sections in the pipe that break the siphon between the engine exhaust manifold and the exhaust conduits. To this extent, they extend above the water line of the boat. Thus, the riser will prevent back pressure from forcing water into the engine.

Each engine manufacturer makes an exhaust system which is designed specifically for a particular engine. Furthermore, in many instances, the engines and their exhaust systems are particularly designed for a certain boat. Thus, in the event that an engine is moved from one boat to another, the exhaust system, and in particularly, the riser may be totally inadequate. Thus, in the new boat, the entire exhaust system may be located below the water line. Furthermore, because of the location of the manifold or the termination of the water cooled pipe in the exhaust system, it may be necessary to cut or deform structural members in order to make an overboard hose connection.

Thus, the exhaust systems presently know for marine engines have a low degree of interchangeability because of the inflexibility of their exhaust systems.

Accordingly, this invention relates generally to an exhaust system which is comprised of a plurality of interchangeable conduit sections which may be arranged in end-to-end relation to define a system having any desired configuration.

The invention can best be described by referring to the accompanying drawing wherein a presently preferred embodiment is illustrated and wherein

FIG. 1 is a side elevation view of a marine engine having an exhaust system of the type disclosed herein.

FIG. 2 is a sectional view of the marine exhaust system illustrated in FIG. 1.

FIG. 3 is a sectional view taken along line 3--3 of FIG. 2.

FIG. 4 is a detail of a portion of FIG. 2, but on an enlarged scale.

FIG. 5 is a view similar to FIG. 1, however, the marine exhaust system is arranged in a different configuration.

Now referring to the drawing for a detailed description, a marine engine 10 comprising an exhaust manifold 12 and an exhaust system 14 is illustrated in FIG. 1.

The exhaust system comprises a plurality of water cooled conduit sections which are connected to each other in a desired configuration. They are connected to an exhaust hose 18 by a suitable hose adapter 20 and to the exhaust manifold 12 by another adapter 22.

The adapter 22 may comprise a flange 24 which is fastened to the exhaust manifold 12 by a plurality of bolts 26. It is connected in end-to-end relation with other conduit sections and forms an exhaust system of any configuration.

Adapter 22 comprises an inner wall 32 which supports flange 24. An outer wall 34 is supported on the inner wall by an inwardly directed wall portion 35. The space between the inner and outer walls defines a cooling water passage 36. The inner wall 32 defines a passage 38 for exhaust gases. An opening 40 may be provided in outer wall 34 to enable cooling water to enter passage 36. The opening 40 may be threaded so that suitable piping may be used to connect it with a pump so that water may be introduced into passage 36.

A curved conduit section 41 is shown connected in end-to-end relation with the adapter 22. It includes a cooling water passage 36' and an exhaust gas passage 38'. The inner wall 32' defines the exhaust gas passage while the space between the inner and outer walls 32' and 34' define the cooling water passage 36'. All of the curved conduit sections 41 have the same configuration as conduit section 41. The inner and outer walls are spaced from each other by webs 43 as seen in FIG. 3. The webs may be formed at the ends of the conduit sections as they are formed.

A straight conduit section 44 is shown connected in end-to-end relation with a curved conduit section. It includes a cooling water passage 46 and exhaust gas passage 48. Inner wall 50 defines the exhaust gas passage 48 while the space between the inner wall 50 and the outer wall 52 defines the cooling water passage 46.

The curved conduit sections 41 may have any convenient degree of curvature. Preferably they should be curved through a right angle so that only two of such sections are needed to form a reverse turn. However, if desired, they may be curved through an angle of 30.degree., 45.degree. or 60.degree..

Similarly, the straight conduit sections may have any convenient length or they may be provided in a plurality of different lengths.

The last conduit section in the exhaust system is hose adapter 20. As seen in FIG. 2, adapter 20 comprises an inner wall 58 which defines passage 60 for exhaust gases and an outer wall 62. The space between the inner and outer walls defines a cooling water passage 64.

The outer wall 62 terminates at an intermediate portion of the hose adapter 20 by virtue of an inwardly directed wall portion 66.

Circumferentially spaced apertures 70 in inner wall 58 connect the exhaust gas passage 60 with the cooling water passage. It is preferred that a plurality of apertures be provided in order to maximize the amount of cooling water per unit time which passes into passage 60. However, it is apparent that only one such aperture need be provided.

The inner wall 58 has a rearwardly directed extension 68 which may be connected to exhaust hose 18. Preferably, the exhaust hose is telescopically received over extension 68. However, it may be connected thereto in any convenient fashion.

It is preferred that the inner and outer walls of each of the conduit sections be concentric and that they have the same cross section so that adjacent sections may be assembled with adjacent cooling water passages and adjacent exhaust gas passages interconnected. Furthermore the conduit sections should have a cross section which enables adjacent conduit sections to be rotated with respect to each other while maintaining communication between the adjacent exhaust gas passages, and cooling water passages. The preferred cross section is circular since this gives the maximum degree of flexibility, however, if desired the sections could be multi-sided; it being understood that with less sides, there is less control over the amount of rotation between adjacent conduit sections.

The various conduit sections 41 and 44 may be provided with threaded openings 62 in their outer walls 34 and 52. The openings are in communication with the cooling water passages. They provide a means in addition to opening 40 for connecting the cooling water passages in the various sections to suitable sources of cooling water. It is contemplated that after the exhaust system is installed, those openings 40 and 48 which are not necessary for the introduction of cooling water may be closed by suitable plugs (not shown).

As best seen in FIGS. 2 and 3, suitable means are provided for interconnecting adjacent conduit sections in end-to-end relation.

The interconnection means comprises outwardly directed flanges 72 supported by the outer walls of each conduit section. The flanges may be positioned in any convenient location along the conduit sections. However, it is preferred that the flanges be positioned so that their front faces 74 (FIG. 4) are substantially coplanar with the end face of the conduit section while their rear faces 76 slope away from the outer wall and toward the front face.

Thus, when two conduit sections are arranged in end-to-end relation so that their exhaust gas passages are aligned and their cooling water passages are aligned, the front faces 74 of their respective flanges 72 are in facing relation to each other and their rear faces define a generally triangularly shaped joint.

A suitable sealing gasket 78 may be interposed between the abutting end faces of the various conduit sections in order to assure that there is no leakage at the end faces of exhaust gases or cooling water.

Clamps 80 may be used to interconnect adjacent pipe sections. Preferably, the clamps are generally triangular in cross section to the extent that their side walls 82 are sloped to correspond with the slope of rear faces 76. Thus, as the clamps are tightened they draw the flanges and their respective conduit sections into close abutting relation to each other. The clamps 80 may be tightened over the flanges by threaded fasteners 83 and nuts 84 as seen in FIG. 3.

Significantly, the conduit sections may be purchased in disassembled form. The exhaust system may be assembled after the engine is installed in the boat. By using a combination of curved conduit sections and straight conduit sections, and by rotating adjacent conduit sections with respect to each other as needed, the exhaust system may be constructed so that any desired configuration can be formed.

In the arrangement shown in FIG. 1, the engine is relatively close to the water line 88. Thus, only two curved conduit sections 41 are needed to give the riser adequate height. The straight conduit section is used to clear certain operating parts off the engine. Further, curved conduit sections 41 and 41' may be rotated with respect to each other so that the exhaust system passes the engine on the observer's side. Conduit sections 41 are curved through about 90.degree.. Thus, a quarter of a turn is accomplished by using one section whereas a U turn is accomplished by using two such curved conduit sections. As indicated above, curved conduit sections having any degree of curvature desired may be employed.

In FIG. 5, for example, the engine 10' is set relatively low with respect to the water line 88'. Thus, straight conduit section 44' is interposed between two of the curved conduit sections to raise at least a portion of the exhaust system above the water line.

In operation, hot gases are discharged from the exhaust manifold 12. They pass through the exhaust gas passages 38, 48 and 60 in the interconnected conduit sections. The cooling water is introduced through one of the openings 40 or 62. The cooling water passes through the interconnected cooling water passages 36, 46 and 64 so that the outer walls of the conduit sections are relatively cool.

At an appropriate place, such as hose adapter 20, the cooling water is mixed with the exhaust gases by passing through apertures 70 in inner wall 58. The combination of exhaust gases and water pass through exhaust hose 18 and overboard.

The exhaust system operates in this manner without regard to its configuration.

The exhaust system which is described herein has a number of significant advantages. Thus, it can be assembled after the engine is installed in the boat. It is fully flexible to the extent that the conduit sections are interchangeable with each other and can be rotated or swiveled to any desired extent with respect to the next adjacent conduit section while still maintaining the cooling water and exhaust passages without leakage. It can be constructed to any convenient height or length by the use of the curved and straight conduit sections. Thus, if necessary the exhaust system may be assembled from all straight conduit sections or all curved conduit sections. Further, with some engine installations, it may be only necessary to use one conduit section between the manifold and hose adapters. Additionally because the various conduit sections are interconnected by clamps, the system may be adjusted or modified at any time.

While the invention has been described with respect to certain forms thereof, it is apparent that many other forms and embodiments will be apparent to those skilled in the art in view of the foregoing description. Thus, the scope of the invention should not be limited by that description, but, rather, only by the scope of the claims appended hereto.

Claims

We claim:

1. An exhaust system of the type that is water cooled for a marine engine comprising a plurality of interchangeable conduit sections, said conduit sections comprising a first wall member defining a passage for exhaust gases, a second wall member around said first wall member, the space between said first and second wall members defining a passage for cooling water, said conduit sections being disposed in end-to-end relation and comprising end faces, said end faces on adjacent conduits being the same so that said adjacent conduit sections can be rotated with respect to each other while maintaining said exhaust gas passages in communication with each other and said cooling water passages in communication with each other, means for coupling at least one of said conduit sections to an engine exhaust manifold so that the exhaust gases therefrom flow through said exhaust gas passages, means on at least one of said conduit sections for coupling said water passage to a supply of cooling water, means for connecting said adjacent conduit sections in said end-to-end relation, and means for mixing water with the exhaust gases.

2. An exhaust system as defined in claim 1 wherein said means for connecting said adjacent conduits comprises an outwardly directed flange supported by said second wall members and means for clamping said flanges on adjacent conduit sections to each other.

3. An exhaust system as defined in claim 2 wherein each of said flanges has a front face which is coplanar with its respective end face, and a rear face which slopes away from said second wall member and toward said front face so that when said conduit sections are placed in end-to-end relation said rear faces define a generally triangularly shaped joint, and clamps for overlying said joints, said clamps having a generally triangular cross section, and means for tightening said clamps over said joints so that said adjacent conduit sections are drawn together.

4. An exhaust system as defined in claim 3 including a gasket disposed between adjacent conduit sections.

5. An exhaust system as defined in claim 1 wherein said means for mixing water with the exhaust gases comprises at least one aperture in the first wall member of at least one of said conduit sections to enable the water in said cooling water passage to enter said exhaust gas passage and mix with said exhaust gases therein.

6. An exhaust system as defined in claim 5 wherein said cooling water passage ends at an intermediate portion of said last named conduit section so that said second wall member extends beyond said first wall member, and a hose telescopically received over the portion of said second wall member that extends past said first wall member so that a mixture of cooling water and exhaust gas passes through said hose.

7. An exhaust system as defined in claim 1 wherein at least one of said conduit sections is straight and at least one of said conduit sections is curved.

8. An exhaust system as defined in claim 1 where at least some of said conduit sections are curved through a right angle.

9. An exhaust system as defined in claim 1 wherein at least one of said conduit sections is curved.

10. An exhaust system as defined in claim 1 wherein at least one of said conduit sections is straight.