Marine exhaust with dual cooling

Details Marine exhaust with dual cooling Marine exhaust with dual cooling

2000-06-01

2002-06-18

Morano, S. Joseph (Department: 3617)

Marine propulsion

Means for accomodating or moving engine fluids

Cooling for engine

Reexamination Certificate

active

06406344

ABSTRACT:

BRIEF DESCRIPTION OF THE DRAWINGS
The features and advantages of the present invention will become apparent from the following detailed description of the invention when read with the accompanying drawing in which a watercraft is illustrated as having an exhaust pipe having connections to a first supply of water and to a second supply of water.
DETAILED DESCRIPTION OF THE INVENTION
The FIGURE illustrates a watercraft
10
having a hull
12
with an internal combustion engine
14
disposed within the hull. The engine
14
has an exhaust pipe
16
passing through a transom
18
to the exterior of the hull
12
. The engine
14
is connected to a stern drive
20
as is known in the art of inboard/outboard marine craft. Although illustrated herein as embodied as an inboard/outboard powered watercraft, the present invention may be embodied in any style of watercraft, including inboard, outboard and inboard/outboard applications.
Watercraft
10
is equipped with an engine cooling apparatus
22
which includes a pump
24
and associated water jacket
23
and piping
25
. Engine cooling apparatus
22
is operable to draw water from a body of water
42
exterior to the hull
12
, to circulate the water through various engine cooling passages (not shown) and water jacket
23
to remove heat from the engine
14
, and to return the heated water to the exterior of hull
12
. Engine cooling apparatus
22
is an active apparatus in the sense that pump
24
provides the motive force for the circulation of coolant through the cooling apparatus
22
. As used herein, the term “active apparatus” is meant to include only those components or collection of components which generate their own movement to accomplish their intended design function. Engine cooling apparatus
22
is an active apparatus because pump
24
must be operated in order to circulate coolant there through. As used herein, the term “passive apparatus” is meant to include only those components or groups of components which can perform their intended design function without self generated motion. In addition to providing an engine cooling function, engine cooling apparatus
22
is connected to the exhaust pipe
16
by a first fluid connection such as conduit
26
. Conduit
26
is operable to direct a first flow of water
28
from the engine cooling apparatus
22
into exhaust pipe
16
to cool exhaust gas
30
and downstream portions of pipe
16
.
The FIGURE also illustrates an auxiliary water supply
32
operable to provide a second flow of water
34
into the exhaust pipe
16
upstream of muffler
54
. As illustrated in the figure, the auxiliary water supply
32
includes a tube
38
having a funnel shaped opening
36
disposed on a forward facing surface of the stern drive
20
. As the watercraft
10
is moved forward through body of water
42
, tube
38
functions as a Pitot tube operable to force water through conduit
40
and into exhaust pipe
16
. The auxiliary water supply
32
is a passive apparatus since its functioning to deliver cooling water
34
to exhaust pipe
16
does not require the self generated movement of any of the components of the water supply
32
. The second flow of water
34
augments the cooling capability of the first flow of water
28
to further reduce the temperature of the exhaust gas
30
. Opening
36
is preferably funnel shaped in order to increase the flow of water through conduit
40
as the watercraft is moved through the body of water
42
. One may appreciate that the opening
36
of tube
38
may be disposed on any forward facing surface of watercraft
10
as long as it is located at a point below the water line
44
during the operation of the watercraft
10
. In order to prevent exhaust gas from flowing out of opening
36
when engine
14
is running but watercraft
10
is stationary or moving very slowly, a check valve
46
may be connected in conduit
40
in order to pass fluid flowing into the exhaust pipe
16
but to block fluid from flowing out of exhaust pipe
16
into tube
38
. In order to further increase the volume of the second flow of water
34
, a plurality of openings
36
may be provided at different locations on the exterior of watercraft
10
below waterline
44
. It is desirable that the connections of both conduit
26
and conduit
40
are located on an upstream portion of exhaust pipe
16
in order to minimize the uncooled length of exhaust pipe
16
. In one embodiment the outlet
48
of conduit
40
is disposed on the exhaust pipe
16
at a location proximate the outlet
50
of the conduit
26
. Such proximate locations may include, for example, the outlets
48
,
50
being located on a single flanged insert
52
which is adapted to be installed as part of exhaust pipe
16
. By using such an insert
52
, one can envisioned the auxiliary water supply
32
being installed as a back-fit kit on an existing watercraft that is already equipped with a connection between the engine water jacket
23
and the exhaust pipe
16
.
A method of cooling the exhaust pipe
16
of a watercraft
10
includes the steps of directing a first flow of water
28
from an engine cooling apparatus
22
into the exhaust pipe
16
of an engine
14
. A second flow of water
34
may then be. directed from an auxiliary water supply
32
into the exhaust pipe
16
. The means for directing the second flow of water
34
, such as auxiliary water supply
32
, is preferable a passive apparatus which is operable independent of the means for directing the first flow of water
28
, such as engine cooling apparatus
22
. By disposing the inlet end
36
of a conduit
40
below a waterline
44
of the watercraft
10
, a flow of water
34
will be forced through conduit
40
as the watercraft
10
is moved through a body of water
42
. Thus even upon failure of an engine cooling apparatus
22
, a continued source of cooling water
34
will be supplied to exhaust pipe
16
, thereby preventing damage to the exhaust pipe
16
and associated downstream components such as muffler
54
. Furthermore, the risk of injury to an occupant of the watercraft
10
during periods of continued engine operation following the failure of cooling apparatus
22
is significantly reduced.
In one embodiment, engine coolant apparatus
22
may be designed to provide a flow rate of 30 gpm of water through conduit
26
into exhaust pipe
16
at full throttle operation. With no other cooling flow,this amount of water will cool the. exhaust gas from approximately 1,400 degrees Fahrenheit to 160 degrees Fahrenheit. Auxiliary water supply
32
may be designed to provide a flow rate of 10 gpm of water through conduit
40
into exhaust pipe
16
at full throttle speed. With no cooling flow
28
from the engine cooling apparatus
22
, this auxiliary water supply
32
will cool the exhaust gas to approximately 200 degrees Fahreheit, which is sufficiently low to protect downstream components such as muffler
54
. With both systems operating, the exhaust gas will be cooled to approximately 130 degrees Fahrenheit. While less than optimal for long term operation of engine
12
, the flow of cooling water
34
provided by the auxiliary source of cooling water
32
is adequate to prevent component damage and dangerously high exhaust pipe temperatures for short periods of operation of engine
12
without exhaust cooling flow
26
. A higher flow rate may be provided through the auxiliary water supply
32
by increasing the size of the conduit
40
, and the specific component sizes and resulting temperatures may be selected on an application specific basis using analytical or empirical techniques known in the art.


REFERENCES:
patent: 2462450 (1949-02-01), Wilson
patent: 2935039 (1960-05-01), Thompson
patent: 3169365 (1965-02-01), Benjamen
patent: 3240181 (1966-03-01), Chandler et al.
patent: 3296997 (1967-01-01), Hoiby et al.
patent: RE26400 (1968-06-01), Jasper
patent: 3556041 (1971-01-01), Shimanckas
patent: 3664135 (1972-05-01), Lirette
patent: 3780712 (1973-12-01), Pace
patent: 4184566 (1980-01-01), Baker et al.
patent: 4504238 (1985-03-01), Neisen
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