U.S. patent number RE36,888 [Application Number 08/841,470] was granted by the patent office on 2000-10-03 for exhaust gas purifying device for an outboard motor.
This patent grant is currently assigned to Sanshin Kogyo Kabushiki Kaisha. Invention is credited to Atsushi Isogawa, Masafumi Sougawa.
United States Patent |
RE36,888 |
Sougawa , et al. |
October 3, 2000 |
Exhaust gas purifying device for an outboard motor
Abstract
An exhaust gas purifying arrangement is provided for an outboard
motor for a watercraft. At least one exhaust port is provided which
opens into a first exhaust passage having a first catalyst member
lining at least a portion of its inner wall. The first exhaust
passage then opens into an exhaust expansion chamber. Next, a
second exhaust passage originates just beyond the expansion
chamber. A second catalyst member is mounted within and across a
section of exhaust passage beyond the first exhaust passage and at
a location above the water line within which the outboard motor
operates. A first passageway is provided which leads from the
second exhaust passage, from a position beyond the second catalyst
member, to an exhaust outlet located at a position below a body of
water in which the watercraft operates. And a second passageway
leads from the second exhaust passage, also from a position beyond
the second catalyst member, to an exhaust outlet located at a
position above the body of water in which the watercraft operates.
The catalyzer system of the invention is particularly useful for
the treating of exhaust gases without introducing undesirable
restrictions to exhaust gas flow.
Inventors: |
Sougawa; Masafumi (Hamamatsu,
JP), Isogawa; Atsushi (Hamamatsu, JP) |
Assignee: |
Sanshin Kogyo Kabushiki Kaisha
(Hamamatsu, JP)
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Family
ID: |
15422527 |
Appl.
No.: |
08/841,470 |
Filed: |
April 22, 1997 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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259186 |
Jun 13, 1994 |
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710789 |
Jun 5, 1991 |
5174112 |
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Reissue of: |
959772 |
Oct 13, 1992 |
05280708 |
Jan 25, 1994 |
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Foreign Application Priority Data
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Jun 5, 1990 [JP] |
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2-147101 |
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Current U.S.
Class: |
60/302; 440/89H;
440/89R |
Current CPC
Class: |
F01N
13/004 (20130101); F01N 3/046 (20130101); F01N
3/28 (20130101); F01N 13/12 (20130101); F02B
61/045 (20130101); F01N 2590/021 (20130101); B63H
20/26 (20130101); Y02T 10/20 (20130101); Y02T
10/12 (20130101) |
Current International
Class: |
F01N
3/04 (20060101); F01N 7/00 (20060101); F01N
3/28 (20060101); F01N 7/12 (20060101); F02B
61/04 (20060101); F02B 61/00 (20060101); B63H
20/00 (20060101); B63H 20/26 (20060101); F01N
003/28 () |
Field of
Search: |
;60/302,299 ;440/89 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2345383 |
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Mar 1975 |
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DE |
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52-8932 |
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Jun 1977 |
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JP |
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55-10043 |
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Jan 1980 |
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JP |
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55-12233 |
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Nov 1980 |
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JP |
|
22000 |
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Jun 1984 |
|
JP |
|
Primary Examiner: Denion; Thomas E.
Attorney, Agent or Firm: Knobbe, Martens, Olson & Bear
LLP
Parent Case Text
.[.This is a continuation of U.S. patent application Ser. No.
07/710,789, filed Jun. 5, 1991, now U.S. Pat. No. 5,174,112..].
.Iadd.This application is a continuation of U.S. patent application
Ser. No. 08/259,186, filed Jun. 13, 1994, which is a reissue of
application Ser. No. 07/973,674, filed Nov. 9, 1992, now U.S. Pat.
No. 5,280,708 and which application is a continuation of
application Ser. No. 07/710,789, filed Jun. 5, 1991, now U.S. Pat.
No. 5,174,112..Iaddend.
Claims
It is claimed:
1. An exhaust gas purifying arrangement for a marine engine for a
watercraft comprising: an exhaust port and an exhaust conduit
system, said conduit system including a first exhaust passage
positioned downstream of said exhaust port and communicating at one
end with said exhaust port; said conduit system further including
an expansion chamber positioned downstream of said first exhaust
passage and communicating with a second end of said first exhaust
passage; said conduit system further including a second exhaust
passage positioned downstream of said expansion chamber and
communicating at one end with said expansion chamber; said exhaust
gas purifying arrangement also comprising at least one discharge
passageway in communication with said conduit system and employable
for discharging exhaust gas out of said marine engine; and further
comprising a catalyst member mounted within a section of said
exhaust conduit system downstream of said expansion chamber;
wherein said catalyst member is positioned higher than the level of
a body of water within which said watercraft is operable; said
exhaust gas purifying arrangement also including means for
precluding water from reaching back up through said conduit system
towards said engine.
2. The exhaust gas purifying arrangement of claim 1 wherein said
expansion chamber is operable at least for quieting operation of
said .[.outboard motor.]..Iadd.marine engine.Iaddend..
3. The exhaust gas purifying arrangement of claim 2 wherein said
catalyst member is an across the duct type element.
4. The exhaust gas purifying arrangement of claim 3 wherein said
discharge passageway comprises a first passageway leading from said
second exhaust passage, from a position downstream of said catalyst
member, to an exhaust outlet located at a position below a body of
water in which said watercraft operates.
5. The exhaust gas purifying arrangement of claim 4 wherein said
discharge passageway further comprises a second passageway leading
from said second exhaust passage, from a position downstream of
said catalyst member, to an exhaust outlet located at a position
above said body of water in which said watercraft operates.
6. The exhaust gas purifying arrangement of claim 1 wherein said
catalyst member is positioned at least as high within said
.[.outboard motor as.]. .Iadd.marine engine at .Iaddend.a level of
a downstream outlet of said first exhaust passage.
7. The exhaust gas purifying arrangement of claim 6 wherein said
expansion chamber has a larger flow cross-sectional area between
said downstream outlet of said first exhaust passage and said
catalyst member than said first exhaust passage.
8. The exhaust gas purifying arrangement of claim 7 wherein said
catalyst member is an across the duct type element.
9. The exhaust gas purifying arrangement of claim 8 wherein said
discharge passageway comprises a first passageway leading from said
second exhaust passage, from a position downstream of said catalyst
member, to an exhaust outlet located at a position below a body of
water in which said watercraft operates.
10. The exhaust gas purifying arrangement of claim 9 wherein said
discharge passageway further comprises a second passageway leading
from said second exhaust passage, from a position downstream of
said catalyst member, to an exhaust outlet located at a position
above said body of water in which said watercraft operates.
11. An exhaust gas purifying arrangement for a marine engine for a
watercraft comprising: an exhaust port and an exhaust conduit
system and an exhaust outlet; wherein said conduit system is
positioned downstream of said exhaust port and communicates with
said exhaust port at one end; and wherein said outlet is positioned
downstream of said conduit system and communicates with said
exhaust conduit system; and further comprising a catalyst member
disposed within said conduit system; wherein said conduit system
includes a trap which precludes water from reaching back to said
catalyst; and wherein said catalyst is located in an upstream
region of said trap; and wherein said conduit system is positioned
below the surface level of a body of water within which the
watercraft is operable.
12. The exhaust gas purifying arrangement of claim 11 wherein said
exhaust outlet is positioned below the surface level of a body of
water within which the watercraft is operated.
13. The exhaust gas purifying arrangement of claim 11 wherein said
trap includes a first downwardly extending passage located
downstream of said exhaust port and an upwardly extending passage
located downstream of said first downwardly extending passage; said
trap further including a bridging passageway communicating said
first downwardly extending passage with said upwardly extending
passage.
14. The exhaust gas purifying arrangement of claim 13 wherein said
conduit system further includes an expansion chamber between said
first downwardly extending passage and said upwardly extending
passage.
15. The exhaust gas purifying arrangement of claim 14 wherein said
expansion chamber comprises at least a portion of said bridging
passageway communicating said first downwardly extending passage
with said upwardly extending passage.
16. The exhaust gas purifying arrangement of claim 14 wherein said
expansion chamber is at least operable for quieting operation of
said .[.outboard motor.]..Iadd.marine engine.Iaddend..
17. The exhaust gas purifying arrangement of claim 14 wherein said
bridging passageway is located beneath the surface of a body of
water within which said watercraft is operated; and wherein said
upwardly extending passage extends from said bridging passageway to
a location above the surface of said body of water within which
said watercraft is operated.
18. The exhaust gas purifying arrangement of claim 17 wherein said
catalyst member is located within said first downwardly extending
passage.
19. The exhaust gas purifying arrangement of claim 18 wherein said
catalyst lines an inner wall of said passage.
20. The exhaust gas purifying arrangement of claim 17 further
comprising a second downwardly extending passage of said conduit
system, wherein said second downwardly extending passage is located
downstream of said trap and communicates said trap with said
outlet.
21. The exhaust gas purifying arrangement of claim 20 wherein said
watercraft includes a transom; and wherein said marine engine is an
outboard motor; and further comprising a clamp bracket mounting
said outboard motor upon said transom; and wherein a region of said
conduit system communicating said upwardly extending passage and
said second downwardly extending passage is located within a
generally horizontally extending plane within which said clamp
bracket and an upper region of said transom are located.
22. An exhaust gas purifying arrangement for a marine engine for a
watercraft comprising: an exhaust port and an exhaust conduit
system, said conduit system including a first exhaust passage
positioned downstream of said exhaust port and communicating at one
end with said exhaust port; said conduit system further including
an expansion chamber positioned downstream of said first exhaust
passage and communicating with a second end of said first exhaust
passage; said conduit system further including a second exhaust
passage positioned downstream of said expansion chamber and
communicating at one end with said expansion chamber; said exhaust
gas purifying arrangement also comprising at least one discharge
passageway in communication with said conduit system and employable
for discharging exhaust gas out of said marine engine; and further
including a trap within said second exhaust passage; said trap
operable for precluding water from reaching back to said expansion
chamber; and further comprising a catalyst member mounted within a
section of said exhaust conduit system upstream of said trap;
wherein said trap is positioned higher than the level of a body of
water within which said watercraft is operable.
23. The exhaust gas purifying arrangement of claim 22 wherein a
portion of said conduit system upstream of said trap is positioned
below the surface level of said body of water.
24. The exhaust gas purifying arrangement of claim 22 wherein said
catalyst member is mounted within said first exhaust passage.
25. The exhaust gas purifying arrangement of claim 22 wherein said
catalyst member is mounted within said second exhaust passage.
26. The exhaust gas purifying arrangement of claim 23 wherein said
portion of said conduit system upstream of said trap which is
positioned below the surface level of said body of water is a part
of said expansion chamber.
27. The exhaust gas purifying arrangement of claim 22 wherein said
expansion chamber is operable at least for quieting operation of
said .[.outboard motor.]..Iadd.marine engine.Iaddend.. .Iadd.
28. An exhaust gas purifying arrangement as set forth in claim 11
wherein the marine engine comprises a portion of the power head of
an outboard motor and which drives a propulsion device disposed
within a drive shaft housing lower unit that depends from the power
head, the expansion chamber being disposed within said drive shaft
housing lower unit and the first exhaust passage comprising an
exhaust pipe extending into said drive shaft housing lower unit and
terminating within said expansion chamber, said one discharge
passageway terminating in an underwater exhaust gas discharge
formed in said drive shaft housing lower unit assembly, the means
for precluding water from reaching back up through said conduit
system toward said catalyst member being disposed within said drive
shaft housing lower unit..Iaddend..Iadd.29. An exhaust gas
purifying arrangement as set forth in claim 28 wherein the conduit
system includes at least one expansion chamber positioned within
the drive shaft housing lower unit..Iaddend..Iadd.30. An outboard
motor as set forth in claim 29 wherein the trap is comprised of a
first upwardly extending section extending upwardly from an inlet
end in said expansion chamber, a horizontally extending section
disposed above the water level and receiving gases from the
upwardly extending section at one end thereof, and a downwardly
extending section extending from the other end of said horizontally
extending section to the underwater exhaust gas
discharge..Iaddend..Iadd.31. An outboard motor as set forth in
claim 30 wherein the horizontally extending section is disposed at
least in part above the upper edge of the transom of a watercraft
to which said outboard motor is attached..Iaddend..Iadd.32. An
outboard motor as set forth in claim 30 further including a
catalyst bed through which the exhaust gases pass from the exhaust
port to the underwater exhaust gas discharge..Iaddend..Iadd.33. An
outboard motor as set forth in claim 32 wherein the catalyst bed is
disposed in the trap portion..Iaddend..Iadd.34. An outboard motor
as set forth in claim 33 wherein the catalyst bed is disposed in
the upwardly extending section of the trap
section..Iaddend..Iadd.35. An outboard motor as set forth in claim
33 wherein the catalyst bed is disposed in the horizontally
extending section of the trap portion..Iaddend..Iadd.36. An
outboard motor as set forth in claim 33 wherein the catalyst bed is
disposed in the downwardly extending section of the trap
portion..Iaddend..Iadd.37. An outboard motor as set forth in claim
33 wherein the horizontally extending section is disposed at least
in part above the upper edge of the transom of a watercraft to
which said outboard motor is attached..Iaddend..Iadd.38. An exhaust
gas purifying arrangement for a marine engine for a watercraft
comprising: an exhaust port and an exhaust conduit system, said
conduit system including a first exhaust passage positioned
downstream of said exhaust port and communicating at one end with
said exhaust port; said conduit system further including an
expansion chamber positioned downstream of said first exhaust
passage and communicating with a second end of said first exhaust
passage; said conduit system further including a second exhaust
passage positioned downstream of said expansion chamber and
communicating at one end with said expansion chamber; said exhaust
gas purifying arrangement also comprising at least one discharge
passageway in communication with said conduit system and employable
for discharging exhaust gas out of said marine engine; and further
comprising a catalyst member mounted within a section of said
exhaust conduit system; said exhaust gas purifying arrangement also
including means for precluding water from reaching back up through
said conduit system towards said catalyst member including
valveless flow control means..Iaddend..Iadd.39. The exhaust gas
purifying arrangement of claim 38 wherein said expansion chamber is
operable at least for quieting operation of said marine
engine..Iaddend..Iadd.40. The exhaust gas purifying arrangement of
claim 39 wherein said catalyst member is in across the duct-type
element..Iaddend..Iadd.41. The exhaust gas purifying arrangement of
claim 40 wherein said discharge passageway comprises a first
passageway leading from said second exhaust passage, from a
position downstream of said catalyst member, to an exhaust outlet
located at a position below a body of water in which said
watercraft operates..Iaddend..Iadd.42. An exhaust gas purifying
arrangement as set forth in claim 38 wherein the marine engine
comprises a portion of the power head of an outboard motor and
which drives a propulsion device disposed within a drive shaft
housing lower unit that depends from the power head, the expansion
chamber being disposed within said drive shaft housing lower unit
and the first exhaust passage comprising an exhaust pipe extending
into said drive shaft housing lower unit and terminating within
said expansion chamber, said one discharge passageway terminating
in an underwater exhaust gas discharge formed in said drive shaft
housing lower unit assembly, the means for precluding water from
reaching back up through said conduit system toward said catalyst
member being disposed within said drive shaft housing lower
unit..Iaddend..Iadd.43. An exhaust gas purifying arrangement as set
forth in claim 42 wherein the means for precluding water from
reaching back up through the conduit system toward the catalyst
member comprising a trap section..Iaddend..Iadd.44. An exhaust gas
purifying arrangement as set forth in claim 43 wherein the trap
section is disposed above the level of a body of water in which the
watercraft is operable..Iaddend..Iadd.45. An exhaust gas purifying
arrangement as set forth in claim 43 wherein the trap section is
disposed
vertically above the catalyst member..Iaddend..Iadd.46. The exhaust
gas purifying arrangement for a marine engine for a watercraft
comprising: an exhaust port and an exhaust conduit system, said
conduit system including a first exhaust passage positioned
downstream of said exhaust port and communicating at one end with
said exhaust port; sand conduit system further including an
expansion chamber positioned downstream of said first exhaust
passage and communicating with a second end of said first exhaust
passage; said conduit system further including a second exhaust
passage positioned downstream of said expansion chamber and
communicating at one end with said expansion chamber; said exhaust
gas purifying arrangement also comprising at least one discharge
passageway in communication with said conduit system and employable
for discharging exhaust gases out of said marine engine; and
further comprising a catalyst member mounted within a section of
said exhaust conduit system and through which all of the exhaust
gas passing through said exhaust conduit system must pass, said
discharge passageway comprising a first passage leading from said
second exhaust passage, from a position downstream of said catalyst
member, to an exhaust outlet positioned to a first exhaust outlet
located at a position below a body of water in which said
watercraft operates and a second passageway leading from dais
second exhaust passage, from a position downstream of said catalyst
member, to an exhaust outlet located at a position above said body
of water in which said watercraft operates and means for precluding
water from reaching back up through said conduit
system toward said catalyst member..Iaddend..Iadd.47. An outboard
motor comprised of a power head containing an internal combustion
engine having at least one exhaust port, a drive shaft housing
lower unit depending from said power head and containing a
propulsion device driven by said engine for powering associated
watercraft, an underwater exhaust gas discharge for discharging
exhaust gases to the atmosphere through the body of water in which
said watercraft is operating, exhaust conduit means for delivering
exhaust gases from said exhaust port to said underwater exhaust gas
discharge, and a catalyst positioned within said drive shaft
housing lower unit and disposed in said exhaust conduit means, the
portion of said
conduit means downstream of said catalyst passing at least in part
through said power head..Iaddend..Iadd.48. An outboard motor as set
forth in claim 47 wherein the power head further comprises a spacer
plate on which the engine is mounted and which is positioned at the
upper end of the drive shaft housing lower unit..Iaddend..Iadd.49.
An outboard motor as set forth in claim 48 wherein the exhaust
conduit means further includes an expansion chamber formed in the
drive shaft housing lower unit..Iaddend..Iadd.50. An outboard motor
as set forth in claim 49 wherein the portion of the conduit means
passing at least in part through the power head communicates at one
end thereof with the expansion chamber..Iaddend..Iadd.51. An
outboard motor comprised of a power head containing an internal
combustion engine having at least one exhaust port, a drive shaft
housing lower unit depending from said power head and containing a
propulsion device driven by said engine for powering associated
watercraft, an underwater exhaust gas discharge for discharging
exhaust gases to the atmosphere through the body of water in which
said watercraft is operating, an above-the-water exhaust gas
discharge for discharging exhaust gases directly to the atmosphere,
exhaust conduit means for delivering exhaust gases from said
exhaust port to said underwater gas discharge, and to said
above-the-water exhaust gas discharge and a catalyst positioned in
said exhaust conduit means through all of which exhaust gases must
pass before they can exit from either said underwater exhaust gas
discharge or said above-the-water exhaust gas
discharge..Iaddend..Iadd.52. An outboard motor of claim 51 wherein
the catalyst is disposed within the driveshaft housing within the
driveshaft housing lower unit..Iaddend..Iadd.53. An outboard motor
comprised of a power head having an internal combustion engine with
at least exhaust port and a surrounding protective cowling, a drive
shaft housing and lower unit depending from said power head and
having a propulsion device driven by said engine for propelling an
associated watercraft, means for attaching said outboard motor to
an associated watercraft, an underwater exhaust gas discharge for
discharging exhaust gases to the atmosphere through the body of
water in which the watercraft is operating, and conduit means for
conveying exhaust gases from said exhaust port to said underwater
exhaust gas discharge, said exhaust conduit means comprising an
exhaust pipe extending from said exhaust port, an expansion chamber
into which said exhaust port terminates, and a catalyst disposed in
said exhaust conduit means downstream of the position where said
exhaust pipe terminates in said expansion
chamber..Iaddend..Iadd.54. An outboard motor of claim 53 wherein
the catalyst bed is disposed in the expansion
chamber..Iaddend..Iadd.55. An outboard motor of claim 53 wherein
the catalyst bed is disposed downstream of the expansion chamber in
the exhaust conduit means..Iaddend..Iadd.56. An outboard motor of
claim 53 wherein the exhaust conduit means comprises a further
expansion chamber positioned within the drive shaft housing and
lower unit..Iaddend..Iadd.57. An outboard motor of claim 53 wherein
the expansion chamber is formed in the drive shaft housing lower
unit..Iaddend..Iadd.58. An outboard motor of claim 57 wherein the
exhaust conduit means comprises a trap section in the power head
downstream of the expansion chamber for precluding water from
entering the exhaust port from the underwater exhaust gas
discharge..Iaddend.
Description
BACKGROUND OF THE INVENTION
This invention relates to an exhaust gas purifying device for a
marine engine and more particularly to an improved and highly
effective system for treating the exhaust gases of an engine prior
to their discharge to the atmosphere.
In many types of applications for internal combustion engines, the
engine exhaust gases are delivered to the atmosphere through
alternate exhaust gases discharges. For example, in connection with
outboard motors, it is normally the practice to discharge the
exhaust gases through an underwater exhaust gas discharge when
traveling at high speeds. However, when traveling at lower speeds
and when the high speed exhaust gas discharge is more deeply
submerged, the exhaust gases are normally delivered directly to the
atmosphere through an above the water exhaust gas discharge.
Although such arrangements are satisfactory, if it is desired to
treat the exhaust gases with a catalyzer so as to prevent the
discharge of unwanted exhaust gas constituents to the atmosphere,
the system for treating the exhaust gases can be extremely
cumbersome.
In a conventional exhaust gas purifying device for outboard motors,
a catalyst is disposed at a position in an exhaust passage
connecting exhaust ports of the engine to an expansion chamber. The
catalyst, however, may create a flow resistance which chokes the
exhaust passage and results in decreased engine performance.
It is, therefore, a principal object of this invention to provide
an improved and highly effective arrangement for treating the
exhaust gases of an internal combustion engine in which the exhaust
system has two different atmospheric discharges.
It is a further object of this invention to provide an improved
catalyzer system for treating the exhaust gases without introducing
undesirable restrictions to exhaust gas flow.
SUMMARY OF THE INVENTION
An exhaust gas purifying arrangement is provided for an outboard
motor for a watercraft comprising at least one exhaust port which
opens into a first exhaust passage having a first catalyst member
lining at least a portion of an inner wall of the first exhaust
passage. Further, an exhaust expansion chamber is provided with the
first exhaust passage opening into the exhaust expansion chamber.
Next, a second exhaust passage originates just beyond the expansion
chamber. A second catalyst member is mounted within and across a
section of exhaust passage beyond the first exhaust passage. At
least one discharge passageway is provided, positioned beyond the
second catalyst member, for discharging the exhaust gas from the
outboard motor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view, with portions broken away, of an
outboard motor constructed in accordance with an embodiment of the
invention.
FIG. 2 is a cross-sectional view taken along the line II--II of
FIG. 1.
FIG. 3 is a cross-sectional view taken along the line III--III of
FIG. 1.
FIG. 4 is a cross-sectional view taken along the line IV--IV of
FIG. 1.
FIG. 5 is an enlarged side elevational view, with portions broken
away, of
an outboard motor constructed in accordance with a second
embodiment of the invention.
FIG. 6 is a cross-sectional view taken along the line VI--VI of
FIG. 5.
FIG. 7 is an enlarged side elevational view, with portions broken
away, of an outboard motor constructed in accordance with a third
embodiment of the invention.
FIG. 8 is a cross-sectional view taken along the line VIII--VIII of
FIG. 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to FIG. 1, an outboard motor constructed in
accordance with an embodiment of the invention is identified
generally by the reference numeral 2. The outboard motor includes a
powerhead, indicated generally by the reference numeral 4 and
containing an internal combustion engine 6 that is surrounded by a
protective cowling 8. The engine 6 is of any known type, for
example, a multi-cylinder reciprocating engine operating on the
two-cycle principle. In accordance with conventional outboard motor
practice, the engine 6 is disposed so that its output or crankshaft
rotates about a generally vertically extending axis.
Depending from the powerhead 4 and affixed to it in a known manner
is a drive shaft housing, indicated generally by the reference
numeral 10, in which a drive shaft, indicated by the reference
numeral 12 is contained and is rotatably supported in a suitable
manner. The driveshaft 12 extends through the drive shaft housing
10 into a lower unit 14 that is affixed to the drive shaft housing
10 and in which a suitable forward, neutral, reverse transmission,
indicated by the reference numeral 16, is positioned for driving a
propeller shaft 18, which, in turn, has a propeller 20 mounted at
its rearward end.
A steering shaft 22 is affixed to the driveshaft housing 10 and is
journaled within a swivel bracket 24 for steering of the outboard
motor 2 about a vertically extending axis. The swivel bracket 24
is, in turn, pivotally supported by means of a pivot pin 26 and
clamping bracket 28 for tilting movement of the outboard motor 2
about a horizontally disposed tilt axis defined by the pivot pin
26. The clamping bracket 28 may be detachably connected to a
transom 30 of an associated watercraft.
The engine 6 is of the water-cooled type and the coolant is derived
from the body of water in which the outboard motor 2 operates
through a water intake 32 that is positioned within the lower unit
14 and from which a supply conduit 34 extends. The supply conduit
34 terminates at a coolant pump 36 that is disposed at the lower
end of the drive shaft housing 10 and which is driven by the drive
shaft 12 in a known manner. Pressurized coolant is delivered from
the pump 36 to the engine 6 through a supply line 38 that extends
upwardly through the drive shaft housing 10 and which terminates at
an inlet of the engine 6.
Referring now additionally to FIGS. 2 through 4 a first embodiment
of the exhaust gas purifying arrangement in accordance with the
invention will be described.
As shown in FIG. 4, three exhaust ports, indicated generally by the
reference numeral 40, are positioned by each of three cylinders,
indicated by the reference numeral 42, located within the cylinder
block 39 of the engine 6. The timings at the three exhaust ports 40
are set to differ by 120 degrees from each other. This makes it
possible to utilize the pulsation effect of the exhaust to ensure
the desired level of engine performance.
The three exhaust ports 40 open into a single exhaust gas conduit
44 located within a spacer plate 46. The spacer plate 46 is
positioned immediately below the cylinder block 39. The spacer
plate 46 further accommodates a cooling water jacket 41 in
conjunction with the cylinder block 39 of the engine 6. The conduit
44 leads downwardly to a vertically disposed first exhaust passage
48 comprised of an exhaust pipe 49 and located within the upper
casing 50 of the driveshaft housing 10. It should be noted that
each sectional area taken across the width of the first exhaust
passage 48 from an uppermost region of the passage 48 to a
lowermost region of the passage 48 progressively increases.
Furthermore, the minimum sectional area taken across the width of
the uppermost region of the first exhaust passage 48 is greater
than any sectional area taken across the width of any one of the
exhaust ports 40.
A first catalyst 52 lines at least the lower part of the exhaust
pipe 49 forming the first exhaust passage 48. This first catalyst
52 cleans that portion of the exhaust gases which impinge upon the
catalyst 52 during the gases' downward flow through the passage
48.
The bottom end of the first exhaust passage 48 opens into an
expansion chamber 54, employed to quiet the operation of the
outboard motor 2. The walls of the expansion chamber 54 are
comprised of a muffler 56 and a dividing baracade 57 integrally
formed with the muffler 56. As indicated by the arrows, the exhaust
gases flow from the first exhaust passage 48 and down into the
expansion chamber 54, at which point they turn upwardly toward the
top of the expansion chamber 54. At this point the exhaust gases
turn downwardly again, in a direction toward the rear of the
outboard motor 2, and enter a second downwardly extending exhaust
passage 58.
Mounted by way of fixtures 60 within and across the second exhaust
passage 58 is a second catalyst member 62, through which the
exhaust gases must pass on their way through this passage 58. The
catalyst 62 is positioned within the second passage 58 at a
location higher than the waterline L of the body of water within
which the watercraft is operated.
It is to be further noted that any sectional area taken across the
width of the second exhaust passage 58 is larger than the minimum
sectional area taken across the width of the uppermost region of
the first exhaust passage 48. Thus, from the discussion above, it
can be seen that the sectional areas progressively increase as the
gas moves from the exhaust ports 40 then to the first exhaust
passage 48 and on to the second exhaust passage 58. This increase
in sectional areas reduces flow resistance of the exhaust gases as
they travel along their flowpath.
A water jacket 64, for containing cooling water, is formed by an
outer side of the muffler 56 and an inner side of an integral
extension, forming a wall 63, of the upper casing 50, and surrounds
a portion of the expansion chamber 54 and the second exhaust
passage 58. To further aid in containing the water a sealing means
65 insures that the area between the lowermost portion of the
muffler 56 and the wall 63 is watertight. Coolant water for filling
the water jacket 64 is provided via a small passageway 66 extending
downwardly from the cooling water jacket 41, as seen in FIG. 1.
After passing through the second catalyst 62 and arriving at an
area just beneath the second catalyst 62 within the second exhaust
passage 58, the exhaust gases can take either of two pathways
leading outside of the propulsion unit. The primary exhaust
passage, which discharges gases into the body of water within which
the watercraft is operated and is the pathway utilized when the
watercraft is operating at high speeds, will be discussed first.
Next, the secondary exhaust passage, which discharges exhaust gases
directly into the atmosphere and is utilized when the watercraft is
operating at low speeds, will be discussed.
When traveling at high speeds, the exhaust gases are delivered from
the area just below the catalyst 62 within the second exhaust
passage 58 to an underwater exhaust gas discharge. Specifically,
the exhaust gases proceed in a downward direction, indicated by the
arrows, through a pathway within the lower unit 14. Ultimately, the
exhaust gases flow through the hub area of the propeller 20 and are
discharged through an exhaust outlet 70. The through the hub
exhaust gas outlet 70 is extremely effective in silencing the high
speed exhaust gases from the engine 6.
However, when operating at lower speeds the degree of submersion of
the underwater exhaust outlet 70 is too great and the back pressure
on the idling gases of the engine 6 will be too high to allow
efficient operation. For that reason, there is provided a
secondary, or low speed, exhaust gas discharge pathway.
An opening 74 is provided in the area just beneath the second
catalyst 62 in a lower wall of the second exhaust passage 58. The
opening leads directly into a bypass portion 78, formed by an outer
wall 80, which extends upwardly from a position below the water
line of the coolant water within the water jacket 64 to a cavity 82
above the water line and inside of the upper casing 50 of the
driveshaft housing 10 and outside of the muffler 56. The exhaust
gas flowpath through the opening 74 and upward into the upper
casing 50 region is depicted by arrows; and is shown specifically
in FIG. 3. Finally, a secondary exhaust outlet 84 is located at an
upper portion of the cavity 82 and within the upper casing 50,
which opens to the atmosphere.
It is to be noted that regardless of whether the exhaust gases are
discharged via the high speed discharge pathway and through the
exhaust outlet 70 or, on the other hand, via the low speed
discharge pathway and through the secondary exhaust outlet 84, they
will have passed along the first catalyst 52 as well as through the
second catalyst 62; thus, assuring cleaning of the gases at any
watercraft operating speed.
Two additional embodiments of the invention are depicted in FIGS. 5
through 8. Like reference numerals employed in the description of
the first embodiment represent like elements in these two
additional embodiments, which follow. Aspects of the following two
embodiments not specifically addressed can be considered to be
similar to those of the first embodiment.
FIGS. 5 and 6 show the second embodiment of the invention. Exhaust
gases initially flow downwardly, from the gas conduit 44, through
the first exhaust passage 48, which is at least partially lined
with a first catalyst 52. Upon exiting the first exhaust passage 48
the exhaust gases enter an expansion chamber 54. After passing into
the expansion chamber 54 the exhaust gases turn upwardly and flow
in an upward direction. Positioned above the expansion chamber 54,
and held in place by fixture members 60, is a second catalyst
member 62. The second catalyst member 62 is located between a
muffler 56 and an integrally formed dividing barricade 57. The
second catalyst member 62 extends across the entire flow path of
the exhaust gases, so that all of the gases must pass through the
catalyst during their upward flow.
Just above the second catalyst member 62 the second exhaust passage
58 begins. Along the upper portion of the second exhaust passage 58
a concave region 100 is formed within the spacer plate 46. The
exhaust gases are guided by this construction rearwardly with
respect to the engine 6, and then in a downward direction, as
indicated by the arrows.
The exhaust gases continue downwardly if the watercraft is
operating at a high speed and flow along a discharge pathway like
that of the high speed discharge pathway of the first embodiment,
ultimately being expelled via a through the hub arrangement within
the propeller FIG. 1).
If the watercraft is operating at a low speed, the exhaust gases
follow a discharge pathway similar to that of the low speed
discharge pathway of the first embodiment. Specifically, the gases
pass through an opening 74 and then upwardly through a bypass 78
which opens into a cavity 82. Finally the gases are discharged
through a secondary exhaust outlet 84 located near an upper end of
the cavity 82.
With the embodiment of FIGS. 5 and 6, if water from the body of
water within which the watercraft is operated should flow back
through the exhaust discharge flowpath, from the exhaust outlet 70,
the water will not be able to reach the second catalyst member 62;
and therefore will not disable its catalytic function. Such water
backflow can result from events such as suddenly slowing the
watercraft down from a high speed, or tilting up of the engine.
FIGS. 7 and 8 show the third embodiment of the invention. Exhaust
gases initially flow downwardly, from the gas conduit 44, through
the first exhaust passage 48, which is at least partially lined
with a first catalyst 52. Upon exiting the first exhaust passage 48
the exhaust gases enter an expansion chamber 54. After passing into
the expansion chamber 54 the exhaust gases turn upwardly and flow
in an upward direction. At an upper region of the expansion chamber
54 and just beneath a concave portion 100 of the spacer plate 46,
an opening 110 is located which forms the beginning of the second
exhaust passage 58.
Fastened in place along a lower side of the spacer plate 46 is a
second catalyst member 62. The second catalyst member 62 extends
horizontally across the entire flow path of the exhaust gases, so
that all of the gases must pass through the catalyst during their
upward flow. The second catalyst member 62 is surrounded by a
sleeve 114 member which is, in turn, nested within a
semi-cylindrical portion 116 of the muffler 56 and its integral
dividing barricade 57. A bushing 118 may line the region between
the semi-cylindrical portion 116 and the sleeve member 114.
Further, the catalyst can be cooled by a cooling water jacket 41
formed between the spacer plate 46 and the cylinder block 39.
After passing through the second catalyst member 62, the exhaust
gases continue downwardly if the watercraft is operating at a high
speed and flow along a discharge pathway like that of the high
speed discharge pathway of the first embodiment, ultimately being
expelled via a through the hub arrangement within the propeller
(FIG. 1).
If the watercraft is operating at a low speed, the exhaust gases
follow a low speed discharge pathway. Specifically, the gases pass
through an opening 74 and then horizontally through a cavity 82
towards a secondary exhaust outlet 84 located near an upper end of
the cavity 82, through which the exhaust gases pass on their ways
into the atmosphere.
As with the embodiment of FIGS. 5 and 6, if water from the body of
water within which the watercraft is operated should flow back
through the exhaust discharge flowpath, from the exhaust outlet 70,
the water will not be able to reach the second catalyst member 62;
and therefore will not disable its catalytic function.
It should be readily apparent from the foregoing description that a
number of embodiments of the invention have been illustrated and
described each of which depicts an excellent catalyst arrangement
within the exhaust system of an engine for highly effective
cleaning of the exhaust gases. Although a number of embodiments of
the invention have been illustrated and described, it should be
readily apparent to those skilled in the art that various changes
and modifications may be made without departing from the spirit and
scope of the invention, as defined by the appended claims.
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