Marine wet exhaust system

Details Marine wet exhaust system Marine wet exhaust system

1998-07-22

2001-05-08

Chapman, Jeanette (Department: 3748)

Power plants

Internal combustion engine with treatment or handling of...

Treated by washing, or having liquid contact structure

C060S311000

Reexamination Certificate

active

06226984

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to exhaust systems for water craft, and more particularly to improved marine wet exhaust systems for reducing the emission of particulate materials in the exhaust flows of marine engines.
2. Description of the Related Art
The internal combustion engines commonly used to power watercraft generate power through the rapid combustion of organic fuels and the expansion of the combustion products against pistons coupled to a drive shaft. The combustion products typically include particulate materials capable of polluting the surrounding air or water when released. The periodic combustion, expansion and discharge of the combustion products also produces undesirable heat and noise in the exhaust flow from the engine.
Internal combustion engines utilized in watercraft typically use the water supporting the craft for cooling purposes. The water is drawn into the craft and circulated through an engine cooling jacket or engine coolant heat exchanger. The water is then commonly injected into the exhaust system to cool the combustion products so that they might be safely discharged through the hull of the craft without presenting a fire hazard. Accordingly, a marine wet exhaust system must handle not only exhaust gases, but also the waste cooling fluid or water which is injected into the exhaust system.
In addition to safely handling exhaust gases and waste cooling water, a marine wet exhaust system should muffle or attenuate the exhaust noise generated by operation of the marine engine. Muffling of exhaust noise from marine engines has been handled in a number of ways. For example, the exhaust may be discharged below the water level. In outboard engines and in inboard/outdrive installations the exhaust is sometimes routed through the drive unit so that the exhaust gas and waste cooling water are discharged through or adjacent the propeller driving the craft. An exhaust system including a water separator for use in outboard drive units with exhaust routed through the propeller under the water line is disclosed in North et al., U.S. Pat. No. 3,759,041.
Mufflers are often placed along the exhaust conduit running between the engine and the exhaust discharge to attenuate the exhaust noise. One such example is shown in Harbert, U.S. Pat. No. 5,022,877.
Often, marine muffler designs are closely akin to the mufflers used on automobiles, but are constructed of materials such as fiberglass which can better tolerate the marine environment. While such mufflers are popular in the boating industry, many do not provide good attenuation of the noise generated by marine engines.
Furthermore, such mufflers often do not adequately separate water from the exhaust gas, even if they are designed to perform any water separation at all. The engine and muffler are often mounted amidship and located as far as 30 ft. to 40 ft. from the discharge. At these lengths it is difficult to maintain an overall downward grade necessary to drain the waste coolant water separated from the exhaust flow. In practice, the exhaust conduit leading from the muffler to the discharge may curl up-and-down as it crosses various sections of the boat, creating traps where water may accumulate and constrict the exhaust flow.
Even among those devices which do separate cooling water from the exhaust flow, it does not appear that any provision has been made to separate particulate materials from either the cooling water or the exhaust flow before the cooling water and exhaust are discharged into the surrounding water and the atmosphere.
Catalytic converters have been used in land vehicles to adsorb or otherwise remove pollutants from automotive exhaust flows. Such devices are less practical in marine craft, however, inasmuch as the very high temperatures necessary to the reduction processes in the converters cannot be tolerated in the less efficiently ventilated engine spaces in water craft.
Consequently, there remains a need for a marine wet exhaust system capable of both attenuating exhaust noise and separating particulate material before the cooling water and the exhaust are discharged.
SUMMARY OF THE INVENTION
This need is addressed by means of the marine wet exhaust system of the present invention. The marine wet exhaust system of the present invention includes a centrifugal water separator having a cooling water outlet in series with a filter for removing particulate materials.
The structure of the centrifugal separator is not critical to the present invention. Nonetheless, a preferred centrifugal water separator is a combined muffler/water separator of the type described in U.S. Provisional Application No. 60/003,073, filed Aug. 31, 1995, and U.S. patent application Ser. No. 08/703,346, filed Aug. 26, 1996, the disclosures of which are incorporated by reference. The preferred combined muffler/water separator comprises a generally cylindrical housing having an inlet structure for inducing the exhaust flow to rotate about a longitudinal axis of an interior of the housing. A first outlet positioned along the axis conducts dried exhaust gas from the housing while a second outlet spaced from the first outlet drains water (and the entrained particulate materials) from the housing. Preferred inlet structures include tangential inlets and inlets near which baffle or vane structures are mounted for deflecting the exhaust flow along an inner wall of the housing.
The structure of the filter is not critical to the present invention. Nonetheless, the preferred filter is a conventional fibrous-type filter for separating and retaining particulate materials larger than a pre-selected mesh size. The preferred filter includes a removable filter cartridge and a holding tank for retaining the particulate materials. The preferred holding tank includes means such as an opening for access to the removable filter and to the stored particulate materials.
The marine wet exhaust system is designed so as to separate the particulate materials from the exhaust flow with the waste cooling water and then filter the particulate materials out of the cooling water as the cooling water flows toward a water drain below the water line. The preferred muffler/water separator is designed such that cooling water and particulate materials are removed near the inner wall of the separator housing. The particulate materials entrained in the separated cooling water flow downwardly into the filter, in which the particulates larger than the pre-selected mesh size are separated and retained for later disposal. Ideally, no significant quantity of particulate materials larger than the pre-selected mesh size will be released into the environment with the exhaust gas or cooling water.
In an especially preferred form, the marine wet exhaust system of the present invention also comprises a first exhaust conduit for conducting exhaust gas from the marine engine to the muffler/water separator; a water injector for injecting droplets of water into the first exhaust conduit; a second exhaust conduit for receiving dried exhaust gas from the muffler/water separator and expelling the exhaust gas to the environment; a cooling water conduit for conducting the separated cooling water and the entrained particulate materials to the filter; and a water drain for discharging the filtered cooling water, preferably below the water line.


REFERENCES:
patent: 714080 (1902-11-01), Whitson
patent: 2142268 (1939-01-01), Gibbs, Jr.
patent: 2487176 (1949-11-01), Pitt et al.
patent: 2721619 (1955-10-01), Cheairs
patent: 2763982 (1956-09-01), Dega
patent: 3296997 (1967-01-01), Hoiby et al.
patent: 3495385 (1970-02-01), Glass
patent: 3630030 (1971-12-01), Wagner
patent: 3759041 (1973-09-01), North et al.
patent: 3815337 (1974-06-01), Lenane
patent: 3831377 (1974-08-01), Morin
patent: 4019456 (1977-04-01), Harbert
patent: 4503680 (1985-03-01), Wood
patent: 4713029 (1987-12-01), Ford
patent: 4781021 (1988-11-01), Winberg
patent: 4831822 (1989-05-01), Yoshimura
patent: 5022877 (1991-06-01), Harbert
patent: 5046977 (1991-09-01), Rodski

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