Note: Descriptions are shown in the official language in which they were submitted.
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OUTBOARD JET DRIVE MARINE PROPULSION SYSTEM WITH INCREASED
HORSEPOWER
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This Application is a Non-Provisional Application claiming priority
(35 USC 119(e)) from U.S. Provisional Application Nos. 60/621,899 filed on
October 25, 2004, entitled DIESEL ENGINE FOR MARINE PROPULSION SYSTEM;
U.S. Provisional Application 60/681,762 filed on May 17, 2005; entitled FUEL
COOLANT FOR OUTBOARD JET PROPULSION ENGINE; Non-Provisional
Application 60/682,597 filed on May 18, 2005, entitled FUEL COOLANT FOR
OUTBOARD JET PROPULSION ENGINE; and U.S. Provisional Application
60/653,652 filed on February 16, 2005 entitled OUTBOARD JET DRIVE MARINE
PROPULSION SYSTEM AND CONTROL LEVER THEREFOR.
BACKGROUND OF THE INVENTION
[0002] This invention relates to outboard jet drive marine propulsion
systems. The present invention relates more particularly to increasing
efficiency and
horsepower in an outboard jet drive for a boat and especially to an outboard
jet drive
having an engine and jet drive mounted in a housing, which is removably
attached to
a boat hull.
[0003] There have been several proposed types of outboard jet drives
for watercraft but most are similar to an outboard motor in which the outboard
motor
propeller and lower unit have been replaced with a jet drive. The jet drive
includes a
jet pump in the lower unit that operates to provide propulsion force for a
watercraft.
There are advantages in employing jet pumps for propulsion units as opposed to
propellers. The jet drive permits operation in shallower water, also the
propeller is
shrouded, and there is less likelihood of injury. There has been a variety of
proposed
constructions for outboard jet drives for positioning the jet pump in
different positions
relative to the hull transom and bottom of the transom but in a typical jet
drive, the
engine and jet drive are located directly in the hull with an opening in the
bottom of
the hull for capturing water passing under the hull and then utilizing the jet
pumps to
thrust the water out the rear of the hull to propel the boat. Outboard jet
drive units are
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made similar to typical outboard motors with a motor driving a drive unit,
which
operates a jet drive unit.
[0004] Generally, the engine package includes an internal combustion
engine mounted in a thin fiberglass hull. The base plate of the hull includes
a water
inlet scoop for feeding water to the pump and an exhaust port for exhausting
the
water. The pumps high-pressure water outlet is pointed in the aft direction
above the
water line to propel the craft by the reaction force resulting from the high
velocity
water jet. In the F.C. Clark U.S. Pat., No. 3,055,175, a marine propulsion
unit takes a
conventional outboard motor and replaces the prop unit with a marine jet motor
using
a pump to issue a jet of water to propel a boat. The Parker U.S. Pat., No.
5,356,319,
is for a boat with a removably inboard jet propulsion unit in which the
integral jet
power unit is encased in a waterproof housing and positioned in a well located
in the
hull and is mounted to be removed from the hull.
[0005] Many of the shortcomings of the prior art were overcome by
Applicant's U.S. Patent No. 6,398,600 in which an outboard jet propulsion unit
is
detachably mounted to a boat so that the main fuel tank and controls are
mounted
within the hull of a boat while the outboard jet drive unit is mounted away
from the
boat in a housing with an engine and is removably attached to the transom of
the
boat. The fuel tank and controls are connected between the hull and outboard
drive
through quick disconnect couplings. The housing is shaped to support an engine
on
a platform directly over the jet drive unit for actuating the jet drive unit
through a
clutch mechanism with the engine and jet drive positioned parallel to each
other.
[0006] The outboard jet unit as designed by Applicant was satisfactory,
however, it did not fully realize the efficiencies of jet propulsion.
Accordingly, an
outboard jet propulsion unit which overcomes the deficiencies of the prior art
is
desired.
BRIEF SUMMARY OF THE INVENTION
[0007] An outboard jet drive includes a housing sealed against the
intrusion of water, the housing having front and rear sides and a top and
bottom. An
engine is disposed in the housing, supported generally horizontally within the
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housing, and a jet drive unit is disposed in said housing generally in
parallel with the
engine. The efficiency of the engine is increased by providing one or both of
a
turbocharger and a cooling system for cooling returned fuel.
[0008] In one embodiment, the housing includes a heat exchange unit
which is vertically disposed within the housing. The heat exchange cools fuel
which
is not combusted by the engine. The cooled fuel is returned to the engine for
combusion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Other objects, features, and advantages of the present invention
will be apparent from the written description and the drawings in which:
[0010] Fig. 1 is a sectional view taken through an outboard jet drive as
mounted on a boat in accordance with the present invention;
[0011] Fig. 2 is a sectional view of an outboard jet drive housing having
a jet drive unit mounted therein;
[0012] Fig. 3 is a rear elevation of the jet drive unit of FIG. 2;
[0013] Fig. 4 is a block diagram of the connected fuel tanks;
[0014] Fig. 5 is an elevation view of a drive assembly for an outboard jet
drive constructed in accordance with the invention;
[0015] Fig. 6 a rear elevation view of an outboard jet drive housing
constructed without the jet drive housing attached thereto;
[0016] Fig. 7 is a drive shaft housing constructed in accordance with the
invention;
[0017] Fig. 8 is a perspective view of a jet drive housing constructed in
accordance with the invention;
[0018] Fig. 9 is a perspective view of a drive shaft support assembly
mounted within said housing in accordance with the invention;
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[0019] Fig. 10 is a side elevation view of another embodiment of the
invention in which a bucket assembly is mounted on the jet drive unit in
accordance
with the invention;
[0020] Fig. 11 is a side elevation view of the bucket assembly in the
open position;
[0021] Fig. 12 is a side elevation view of the bucket assembly in the
closed position;
[0022] Fig. 13 is a sectional view of a saddle assembly for supporting
the bucket assembly;
[0023] Fig. 14 is a side elevation view of a control assembly for the
bucket in the open position;
[0024] Fig. 15 is a side elevation view of a control assembly for the
bucket in the closed position;
[0025] Fig. 16 is a top plan view of the bucket assembly;
[0026] Fig. 17 is a top plan view of a bucket assembly steering a boat to
the left;
[0027] Fig. 18 is a top plan view of a bucket assembly steering a boat to
the right;
[0028] Fig. 19 is a schematic view of the bottom of the housing showing
relative water and airflow;
[0029] Fig. 20 is a schematic diagram showing the relative widths of the
jet inlets and convex portion of the housing;
[0030] Figs. 21A-C are schematic drawings of the water and air flow
relative to the housing and jet intake;
[0031] Fig. 22 is a schematic drawing of the water shape as it moves
past the housing;
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[0032] Fig. 23 is a side elevation view of the air and water movement
relative to the boat and outboard jet unit;
[0033] Fig. 24 is a perspective view of an outboard jet propulsion unit
constructed in accordance with another embodiment of the invention;
[0034] Fig. 25 is a perspective view of a jet pump constructed in
accordance with the invention;
[0035] Fig. 26 is a top plan view of a stator constructed in accordance
with the invention;
[0036] Fig. 27 is a side elevation view of a stator constructed in
accordance with the invention;
[0037] Fig. 28 is a front elevation view of a housing for a jet drive marine
propulsion system constructed in accordance with the invention;
[0038] Fig. 29 is an edge perspective view of a housing for an outboard
jet drive marine propulsion system in accordance with the invention;
[0039] Fig. 30 is a schematic drawing of the relative profiies of a
propulsion system and boat constructed in accordance with the invention;
[0040] Fig. 31 is a side elevation view of a shift plate constructed in
accordance with the invention;
[0041] Fig. 32 is a side elevation view of a throttle plate constructed in
accordance with the invention;
[0042] Fig. 33 is a partial elevation view of a first side of a lever plate
constructed in accordance with the invention;
[0043] Fig. 34 is a partial elevation view of the reverse side of a lever
plate constructed in accordance with the invention;
[0044] Fig. 35 is. a side elevation view of a lever control assembly
constructed in accordance with the invention;
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[0045] Fig. 36 is a schematic view of a turbocharger constructed in
accordance with the invention; and
[0046] Fig. 37 is a schematic view of a fuel cooling system in
accordance with the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0047] Referring to FIGS. 1-3, an outboard jet drive unit 10 is shown
attached to the huil of a boat 11 on the transom 12. The jet drive unit 17
includes a
housing 13 having a platform 14 mounted therein and having a plurality of
flexible
engine mounts 15 attached to the platform 14. An internal combustion engine 16
is
mounted to the engine mounts 15 on the platform 14. Engine 15 is preferably a
diesel engine having a turbocharger with an intercooler, but may be a gasoline
engine as well, and is preferably a conventional car or truck engine. A jet
drive unit
17 is mounted beneath the platform 14 of the housing 13 and is attached to the
front
end 18 of housing 13. The housing 13 is sealed against the intrusion of water
thereto and sealed between the platform 14 and the housing 13 to prevent water
intrusion and to prevent oil or engine antifreeze from escaping therefrom.
[0048] The predominant prior art configuration of inboard jet boats is the
inline setup, that is, the engine is connected in line with the jet drive;
this has the
engine's flywheel and drive pulley facing the transom (back of the boat) from
inside
the boat and the jet attached to it. By turning engine 16 and jet drive unit
17 around
as compared to the prior art (i.e., 180 degrees) so that they are outside the
boat
behind the transom, as shown in the Fig. 1 in accordance with the present
invention,
the engine gear 120 and jet drive pulley 28 are positioned so that they both
face in
the same direction toward the transom from outside the boat, i.e., they face
in the
opposite direction of the inline arrangement. Thus, in this configuration, the
drive
pulley and engine flywheel are facing the back of the boat, but from outside
the boat.
Then, by using the drive belt system 27, the jet is placed substantially
directly below
the engine. In other words the engine and jet are oriented substantially
vertically
stacked and substantially in parallel. It should be appreciated by those of
skill in this
field that by turning the engine around 180 degrees from the inline
configuration, this
will cause the impeller to turn in the opposite direction (backwards) from
other
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impellers in use currently. Thus, the jet drive unit and engine are in essence
installed
"backwards" causing the impeller in the jet drive unit to rotate in the
opposite or
reverse or "backwards" direction, as compared to impellers in jet drive units
configured inline.
[0049] In an exemplary, non-limiting embodiment, engine 16 has a belt
drive 27 having a clutch mechanism therein for connecting the engine 16 to the
drive
pulley 28 of the jet drive unit 17. More particularly, as shown in Fig. 5, a
drive train is
formed between a gear 120 on a flywheel of engine 16 connected on gear 122
(drive
pulley 28) mounted on drive shaft 124 of jet drive shaft 17. In a preferred
embodiment, belt drive 27 is a Kevlar belt, preferably teethed to engage
gears 120,
122 to prevent skipping and slippage.
[0050] While the parallel position is the most efficient and preferred
position for jet drive unit 17 and the internal combustion engine 16 system to
be
placed relative to each other, it is not the only possible position. In
addition, by being
positioned in parallel, it allows use of a standard horizontal engine and
drive belt
drive as illustrated in Figs. 1, 2 and 5 and discussed above.
[0051] While it is preferred for jet drive unit 17 to be positioned below
engine, other locations are contemplated by the present invention, such as on
top,
opposed, or on the side of the internal combustion engine.
[0052] Although acceptable within the scope of the invention, they are
not preferable. By way of example, if jet drive unit 17 is positioned on top
or above
the engine, it will operate, however, it would require pumping water up to the
jet.
The higher the water is pumped, the more power is lost to pumping water and
the
larger the water intake needs to be (the water intake needs to gradually
decrease in
size throughout the water intake system, to avoid air bubbles from forming and
causing cavitation).
[0053] Also, the best water flow for the jet intake is at the bottom center
of the boat, which may create a problem diverting water around the engine.
This
position would also most likely cause the engine to be lower which creates
another
problem. That is corrosion and exhaust riser problems. The lowest part of a
boat or
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marine engine compartment invariably gets water in it. Having the engine low
puts
the engine in the water.
[0054] If the jet drive unit 17 is positioned on one or both sides of engine
16, while this positioning is believed to be better positioning than on top,
it still has
the problems mentioned above, and would require much greater width of the
finished
unit, it may create a weight distribution problem in that engine 16 is much
heavier
than jet drive unit 17, especially if only one jet drive unit is employed. In
addition,
putting too much weight to one side or the other would most likely create
handling
problems with the boat.
[0055] As already indicated, when the jet drive unit is placed on the
bottom or underneath the engine, this positioning is by far the most practical
and
preferred placement. The engine is elevated, reducing problems from corrosion
and
riser problems. The jet is at the lowest possible position, creating the best
water flow
into the jet intake. The weight is centered. Further, by putting the, weight
of the
engine directly over the jet drive unit and the water intake, the water intake
is less
likely to come out of the water as often happens in the current systems. When
the
water intake comes out of the water, both power and maneuverability are lost
in a jet
drive unit.
[0056] It is also preferential for the water path entering and exiting the
jet drive unit to be axial or straight, as opposed to, for example, a circular
or bent
path.
[0057] Furthermore, it should be understood that the engine could be
attached with a chain, or possible with a direct drive system with a series of
two or
more gears, although the belt is preferable. A clutch may be used but is not
required.
[0058] The advantage of the belt drive system is efficiency. The belt
drive in theory transfers 98% of the engine's power to the jet impeller. Other
systems
in practice lose approximately 15% of the engines power by the time power is
transferred to the propeller or jet impeller.
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[0059] Also, it is believed that this is the most cost effective method for
a jet. For the jet to operate at its best efficiency, the jet should be sized
appropriately
to the horsepower and expected load. Most jet boats in operation today are
using
jets sized too small for optimum efficiency. This is done because the jet is
being run
at engine speed. Smaller jets can run at higher speeds (rotations per minute
or
"RPM"), larger jets must operate at lower speeds (RPM). In order for the jet
to
operate at a lower RPM than the engine, some sort of gearing reduction is
required.
Currently, when a reduction is put in place it is done with a transmission.
With the
belt drive system of the present invention, it is able to operate the jet at a
lower RPM
by using different sized gears and the gear size is preferably matched to the
engine
and jet size when installed.
[0060] Jet drive unit 17 extends through the rear 21 of housing 13 out
an opening 20 in the housing 13. The jet drive unit 17 has a water intake 22
and is
positioned to be about level with the bottom 23 of the hull 11. A water
exhaust 24,
providing the exit path for jetted water, extends out the rear of the housing
13. A jet
pump 25 is mounted in the jet drive 17 for drawing the water thereinto through
the jet
pump and out the water exhaust 24. The water path through jet drive unit is
preferably substantially linear as shown. The jet drive unit 17 is shown below
the
water line 26 and is supported on brackets 29 on the front 18 of the housing
13.
[0061] Reference is now made to Fig. 6-9 in which a mounting structure
in accordance with the preferred embodiment for the drive jet unit 17 is
provided. As
discussed above, jet drive unit 17 is mounted to housing 13 in a way to
operatively
cooperate with engine 16. Housing 13 is provided at its rear face 21 with an
opening
20. Opening 20 communicates with the interior of housing 13.
[0062] Jet pump 25 is a series of jet blades radially affixed about drive
shaft 124. Reference is made to Fig. 25 in which a perspective view of a jet
pump
25,constructed in accordance with the invention is provided. Helical blades
500
extend from a support member 502 schematically shown in Fig. 1. Support member
502 is preferably conical. Because the blades are helical and spaced, water is
drawn between the blades in the direction of arrow 0. Because the jet pump
assembly 25 rotates, water is pushed outwardly as well as forwardly. As the
rpms of
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the blade increase, cavitation increases between the blades. As cavitation
increases, thrust is lost. Furthermore, water escapes through the path of
least
resistance. Most goes forward out through water exhaust 24. However, because
of
the spacing between blades, some water travels upstream adding to cavitation
and
loss of power. The greater the cavitation, the less speed and less thrust. The
cavitation decreases as a function of the size of the gap between overlying
blades.
The gap is reduced as a function of 1-((n-x)/n) expressed as a percentage
where n is
the number of current blades and x is equal to the number of additional blades
as
compared to the comparison jet pump. By way of example, if the number of
blades
is increased from 3 to 4, then n=4 and x=1 so that the increase is 1-75%=25%.
If the
increase is from 2 blades to 4 blades, the gap is closed by 50%, assuming
equidistant spacing of the blades. The more blades, the less cavitation;
however,
while thrust may increase, speed does not.
[0063] Accordingly, the jet pump is formed from two types of blades,
impeller blades 510 and induction blades 512. Induction blades 512 draw water
towards impeller blades 510 to provide a more dense water stream to impeller
blades 510 so that impeller blades 510 force a greater mass of water out of
exhaust
24. In effect, induction blades 512 prime the pump.
[0064] Each induction blade 520 of induction blades 512 has a length
LIN and a width WIN. Each induction blade 520 has a lead edge and a trail
edge.
Each induction blade 520 has a non-uniform pitch, i.e. it is bent so that a
leading
edge 522 of each induction blade 520 has a pitch less than the pitch of the
remaining
portion. In a preferred, but not limiting example, leading edge 522 has a
pitch of
about 14 while a trailing portion 524 of induction blade 522 has a pitch of
about 17 .
[0065] Each blade 500 of impeller blades 510 has a length L,M and a
width WiM. The width WIN is substantially smaller, about 50%-85% than the
width
WiM of impeller blades 500. Furthermore, the length LiM of impeller blades 512
is
substantially greater than the length LIN of blade 520. Impeller blades 500
are also
of non-uniform pitch having a leading edge 506, having a lower pitch, than a
trailing
section 504. The change in pitch along each of the blades found in impeller
blades
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510 and induction blades 512 occurs closer to the leading edge than the
trailing
section.
[0066] It should be noted that impeller blades 512 are shown as a
distinct leading section upstream of impeller blades 510. However, it would
still be in
accordance with the invention to provide induction blades 512 interspersed or
interleaved among impeller blades 510. By providing an induction blade in
cooperation with an impeller blade in the jet pump, preferably upstream of the
impeller blades, denser water is carried to the impeller blades providing
better thrust
and speed. By providing at least four impeller blades, the gap is sufficiently
closed
between blades to significantly reduce the reverse flow of water. The addition
of
more blades increases cavitation on acceleration reducing speed. Therefore,
the
induction blades 512 are provided.
[0067] As a result of the action of the blades of jet pump 24, the water
exits exhaust 24 in the direction of arrow P (Figs. 1, 2). However, the water
is
turbulent and energy is flowing in all directions. Accordingly, a stator 600
as shown.
in Fig. 26 is provided at exhaust 24 to collimate water exiting from jet pump
25.
Stator 600 includes a central member 602. In a preferred embodiment central
member 602 is conical. A plurality of blades 604 extend radially from conical
member 602 to a wall of exhaust 24. In a preferred embodiment, a wall 606 is
integrally formed with blade 604 to form a unitary unit which is mounted
within water
exhaust 24 or blades 604 and conical member 602 can be unitarily formed with a
housing structure within water exhaust 24.
[0068] As water flows through stator 600, it is guided to flow in a single
direction, but some energy is lost and the flow of water loses speed. In turn,
the boat
loses speed. However, a volume reduction member 610 extends from conical
member 602 into the exhaust portion of water exhaust 24. In a preferred
embodiment, volume reduction member 610 is merely an extension member from
conical member 602. However, any structure which reduces the volume within
water
exhaust 24 without substantially interfering with the flow path of water
exiting through
stator 600 may be used. By reducing the volume available to the water in water
exhaust 24, the water speed increases, the pressure of the water column
exiting the
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jet at water exhaust 24 is increased, providing increased thrust and speed to
engine
10.
[0069] Jet drive unit 17 may be formed as a removable cartridge. In a
preferred embodiment, jet drive unit 17 is housed in a removable jet housing
206.
Jet housing 206 supports a drive shaft housing 201 in which drive shaft 124 is
disposed. Drive shaft housing 201 is received in opening 20 and extends
through
opening 20 and forms a watertight seal with housing 13. In a preferred
embodiment,
housing 201 is bolted using a bolting plate 202 to a mating bolting plate 204
of
housing 13. Gaskets and seals, as known in the art, are utilized to affix
housing unit
201 to housing 13 in a watertight manner.
[0070] Jet unit 17 is formed as a unit about drive shaft 124. Therefore,
drive shaft 124, mounted within housing unit 201, can be easily mounted to
housing
13 by simply sliding the entire unit including housing 201 through opening 20.
Drive
pulley 28 is affixed to drive shaft 124, which in turn is attached to drive
belt 27, and
the entire jet propulsion unit is affixed to engine housing 13. As a result,
simple
assembly is provided while maintaining a separation between the engine
structure,
which remains away from water to prevent corrosion and the jet unit structure,
which
must come in contact with water.
[0071] In one embodiment, drive shaft housing 201 is slidably received
within jet unit housing 206. Jet unit housing 206 is mounted to the rear
surface 21 of
housing 13 by bolting the housing in the rear. To maintain the overall shape
of the
outboard propulsion system 10, engine housing 13 may be formed with a recess
210
for receiving jet unit housing 206. Housing 206 is provided with a plate 208
for
attachment to housing 13.
[0072] Vibration along drive shaft 124 results in wear and tear on the
drive shaft. This is especially true at each of the ends of the drive shaft
124. As
seen in Fig. 9, brackets 212 affix drive shaft housing 201 to the interior of
housing 13
at an end of drive shaft 124 adjacent drive pulley 28. A bracket 212 is
provided at
either side of drive shaft housing 201 to stabilize drive shaft 124 at its
end.
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[0073] In an exemplary embodiment, the brackets can be made from
milled steel, aluminum, stainless steel or other materials. Stainless steel
provides
the best combination of stiffness, corrosion resistance and weight for the
marine
environment. In the preferred embodiment, brackets 212 need to be attached as
close to the end of drive shaft 124 as possible to provide the best support
although it
is understood and within the scope of the invention, that brackets 212 could
be
attached to various positions in the engine compartment. Attaching brackets
124
above and on each side of drive shaft 124 provides the best support while
keeping
the brackets accessible for maintenance and keeping the fittings, bolt holes,
bolts
and the like as high above the bilge area as possible.
[0074] By placing bracket 202 substantially midway along the length of
drive shaft housing 201, further support of drive shaft 124 is provided. When
attached, flange 202 is disposed between housing 13 and jet unit housing 206,
and
is firmly attached to both, further supporting drive shaft 124 along its
length. As
discussed above, shaft housing 201 slides into the engine housing 13 as well
as the
jet housing 206. The three components are attached at flange 202 by welding,
bolting or other known means and bolt plate 208 of jet housing 206 is bolted
to rear
surface 21 of housing 13. In this way, jet housing 206 is received and
positioned
within a receiving area 210 on the rear surface 21 of housing 13.
[0075] In a preferred embodiment, having flanges close to the middle of
the drive shaft housing provides the best support. Other supports at the end
of the
drive shaft are helpful, but not required. A support system can be made from
milled
steel, aluminum, stainless steel or other materials. Again, stainless steel
provides
the best combination of stiffness, corrosion resistance and weight for the
marine
environment.
[0076] Outboard propulsion unit 10 utilizes a closed loop cooling system
similar to those used in an automobile. In a preferred embodiment, propulsion
unit
uses a water-to-water heat exchanger to cool engine 16 in a similar fashion to
a
radiator in an automobile. The water that circulates through the engine, the
water-
cooled exhaust manifold, and the oil cooler (where applicable) is treated with
fresh
water just like used in an automobile, but without the use of a water tank
type
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radiator. Propulsion unit 10 cannot expose the engine interior to seawater or
dirty
fresh water it utilizes during operation. Rather, the hot engine water is
circulated by
the engine water pump through a heat exchanger where it is cooled by the
circulating seawater. Sea water is pumped through the heat exchanger by the
water
jet eliminating the requirement for a separate engine driven sea water pump
and
eliminating the high maintenance rubber sea water pump impeller.
[0077] In another advantage, the propulsion unit 10 may be equipped
with turbochargers. The marine propulsion unit 10 also includes a stainless
steel and
cupronickel intercooler to cool the compressed air before it is inserted into
the
engine's intake manifold. The process of compressing the inlet air with the
turbocharger increases the temperature of the air. Cooling the inlet air with
seawater
in the intercooler enables the engine to produce more power more economically
and
reduces the smoke and other pollution from the engine exhaust to meet
environmental standards.
[0078] In another advantage, the marine propulsion unit 10 may be
equipped with fuel coolers. It is believed that fuel injected engines deliver
more fuel
to the engine than the engine requires. The excess fuel is returned to the
fuel tank
for use later. The returned fuel is heated by the engine and tends to raise
the
temperature of the fuel in the tank over a period of time. The higher fuel
temperature
reduces the engine power and performance. The fuel cooler eliminates this
problem.
The fuel cooler is constructed of stainless steel and cupronickel and uses
seawater
for cooling.
[0079] Reference is now made to Fig. 24 in which yet another
embodiment of outboard propulsion unit 10 utilizing a cooling system is
provided.
Like numerals are used to indicate like structure for ease of description.
Propulsion
unit 400 includes an engine 16 and a jet unit 17. A heat exchanger 402 is
coupled to
jet unit 17 by hosing 404. Heat exchanger 402 is also coupled to engine 16 by
hosing 406. A second hosing 408 couples heat exchanger 402 to an intercooler
410.
Intercooler 410 is connected by hosing 412 to an exhaust 414 of engine 16.
Furthermore, intercooler 410 is coupled to the fuel line of engine 16 and the
turbo
charger of engine 16.
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[0080] During operation, hosing 404 is coupled to the jet unit 17 and
siphons a portion of the jet stream as it travels through jet unit 17 so that
water under
pressure travels in the direction of arrow M into heat exchanger 402. Hose 406
communicates with piping (not shown, but known in the art) within heat
exchanger
402 which is surrounded by the cool water flowing from hosing 404 into heat
exchanger 402. In this way, engine 16 is isolated from the water passing
through jet
unit 17. The pressure provided by the jet stream and gravity cause heated
water to
exit heat exchanger 402 through hose 408 in the direction of arrow N into
intercooler
410. Intercooler 410 includes piping systems, which communicate with the turbo
charger, exhaust 414, and fuel line of engine 16 cooling the air and fuel
within the
engine to provide greater efficiency for a turbo charged engine. Cooler fuel
increases the horsepower of the engine.
[0081] It should be noted that heat exchanger 402 and intercooler 410
are each preferably oriented vertically relative to the horizontal orientation
of engine
16. In this way, if in fact outboard propulsion system 10 is not running,
gravity drains
the seawater or clear water from heat exchanger 402 into hose 408 or back into
hose 404. In this way, no seawater remains in the heat exchanger 402 longer
than
necessary, reducing the corrosion to any piping within heat exchanger 402 or
structure within intercooler 410. Furthermore, heat exchanger 402 is
preferably
made of stainless steel and cupronickel, both highly corrosion-resistant
alloys to help
ensure that the interior of engine 16 is never exposed to seawater.
Additionally, no
engine flushing is required after each boat trip because a closed cooling
system is
provided, engine 16 should experience a longer and more reliable life.
[0082] Reference is now made to Fig. 37 in which a schematic diagram
of a cooling assembly, generally indicated as 800 is provided for cooling fuel
prior to
combustion which increases the horsepower of the engine. In this embodiment
cooling is performed by heat exchanger 402 rather than inter cooler 410.
System
800 makes use of a fuel cooler 802 positioned at a top end of heat exchanger
402.
The top end is the end opposite the water input 403. The water circulating
within
heat exchanger 402 as shown by Arrows Z. Fuel cooler 802 is disposed within
heat
exchanger 402, so that water within heat exchanger 402 cools fuel within fuel
cooler
802.
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[0083] System 800 also includes a pump/filter 804. A fuel line includes
a fuel hose, a transfer line and a return line with fuel flowing in the
direction of the
arrows. Pump/filter 804 receives fuel along a fuel hose 806. In a preferred
embodiment, the fuel hose 806 connects a fuel tank (not shown and preferably
outside of the housing) to system 800. In a preferred embodiment, a filter 808
is
disposed along fuel hose 806 for preliminarily filtering fuel. A transfer line
810
transfers heated fuel from engine 16, represented schematically, to fuel
cooler 802.
A return line 811 returns cooled fuel to a filter 812. Filter 812, in turn,
mixes the
cooled fuel with the cooled fuel coming from the tank and inputs fuel to a
lift pump
805 which pumps fuel to engine 16 through a second filter 814.
[0084] In a preferred embodiment, the return where the transfer line
merges into the return line, at heat exchanger 402 within fuel cooler 802 may
be a
coil to allow maximum surface area exposure to the cooling effects of heat
exchanger 402.
[0085] In the past, hot fuel, that fuel which had not been combusted by
engine 16, had been returned to the fuel tank in outboard systems. Returning
hot
fuel to a fuel tank generally results in lost horsepower due to the rise in
fuel
temperature which encourages algae growth due to oxygenation and temperature
elevation. Many outboard vessels do not have a facility for fuel return on the
tank.
In accordance with the above structure, by aggressively cooling the fuel at
the top of
heat exchanger 402 and returning cooled fuel to the top of fuel filter 812,
the low
pressure or lift pump 805, allows the return line to the tank to be
eliminated. The
engine can now produce maximum power continuously without the customary
horsepower loss as fuel temperature increases. By not returning hot fuel to
the tank,
horsepower loss can be avoided and algae growth resulting from oxygenation and
temperature elevation is minimized or eliminated. The current invention, as
illustrated in Fig. 37, makes installation easy, safe and inexpensive as it is
a modular
add-on device to the heat exchanger and the fuel line. The present invention
also
allows the use of JP8 (jet fuel) for military use without the heat related
durability
problems associated with such fuel.
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[0086] In prior are outboard and turbo charged marine engines, it was
necessary to match r.p.m.'s to turbine output at low r.p.m. 's. This was
required to
deliver low end (low speed, low torque) power to conventional outboard motors.
However, by providing a jet pump driven by a conventional automobile motor as
a
result of the novel orientation and structure discussed above, the jet of the
present
invention continuously provides a small torque load to the engine, no matter
the
r.p.m.'s. Therefore, there is no need for the waste gate.
[0087] In a preferred embodiment, turbocharger 420 controls increases
in the back pressure by matching the turbo characteristics to the engine
rather than
releasing energy through a waste gate as known in the art. The housing
diameter or
area/radius ratio is adjusted to control the exhaust gas volume and speed to
optimize
turbine speed at maximum r.p.m. to provide more pressure on the housing side.
Reference is now made to Fig. 35 where a schematic diagram of a turbo charger
constructed in accordance with the invention is provided.
[0088] It is often required to obtain extra power from an engine.
Applicants have determined that it is possible to boost a 150 horsepower
engine to a
200 horsepower engine utilizing a turbocharger 420 either alone or in
combination
with cooled fuel. Turbocharger 420 includes a first turbine housing 424. The
housing includes an intake 426, coupled to an exhaust 428 of engine 422. A
turbine
430 is rotatably disposed within turbine housing between input 428 and housing
exhaust 432 so that exhaust from engine 422 exiting through engine exhaust 428
drives turbine 430 as it passes through the blades of turbine 430 towards
exhaust
432. Turbine 430 is in the exhaust flow path. Turbine 430 is larger than
exhaust
turbines used to provide turbo charging of engines providing low end power.
[0089] A second housing 450 has an intake 456 for receiving
atmospheric air and an output 452 providing output to engine 422 into
respective
cylinder chambers. An air compressor 454 is rotatably housed within housing
450
and is along a flow path between air intake 456 and exhaust 452. Air
compressor
454 is smaller than compressors used to provide low end power with an engine.
A
shaft 460 connects turbine 430 to air compressor 454. Therefore, as engine 422
produces exhaust, it spins turbine 430, in turn turning shaft 460 in air
compressor
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454. The turning of air compressor 454 creates a vacuum at exhaust 456 drawing
atmospheric air into housing 450 through compressor 454 and then forced under
positive pressure through exhaust 452 into engine 422. This provides extra
oxygen
in the cylinders 422 of the engine creating larger explosions and more energy
for
driving the pistons.
[0090] By adjusting the area/radies ratios and the size of the
compressor and exhaust turbines greater efficiency are provided. This, alone
or in
combination with the use of cooled fuel, and/or cooled inlet air increases
horsepower
efficiency by over about twenty-five percent; about 150 horsepower to about
200
horsepower in a jet propulsion system.
[0091] As is known in the art, air will sometimes backflow through
housing 450 decreasing efficiency. It is known in the art to provide a waste
gate to
allow excess pressure as a result of the backflow to vent. By sizing housing
450 to
provide the correct volume and velocity of air flow through the housing, the
need for
the waste gate is eliminated.
[0092] This engine and associated control is also suitable for use with
rigid, inflatable boats (RIB) such as those manufactured by Zodiac@ by way of
non-
limiting example. Furthermore, the use of the current engine provides a novel
advantage of a self-maintaining RIB. One shortcoming with RIBs is that the
inflatable structures essentially change volume as a function of the
atmosphere.
Inflatable sections that appear solid when trailered in the sun, lose volume
when
placed in the cooler water. Furthermore, no matter how air tight, inflated
objects do
tend to deflate over time at the valve, the seams or leakage through the
material.
Accordingly, a self-inflating mechanism is desired.
[0093] As discussed above, there is air under pressure traveling
through the engine constructed in accordance with the invention. Generally,
air
travels through the engine at 25 psi. In the present invention, a tap is
provided along
the inlet air passage of the engine for siphoning off a portion of the air
under
pressure. A hose or other type piping or tube couples the tap or a manifold to
the
structure to be inflated. A regulator may be provided along the line formed by
the
tubing. The regulator is a pressure-controlled diaphragm that opens when the
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downstream pressure falls below a predetermined level allowing inflation. Air
may
be released in the reverse direction if pressure in the inflated structure
exceeds a
predetermined amount.
[0094] Reference is now made to Figs. 10-18 in which another
embodiment of the jet engine is provided. Like numerals are utilized to
identify like
structure for ease of description. Water exiting jet exit portion 54 (Fig. 1)
is what
provides the driving force for the outboard jet propulsion engine, and in
turn, the boat
to which it is attached. Because exhaust portion 54 is fixed to the fixed
structure of
housing 13 as described above, a mechanism is required to allow reverse
operation
and steering. As shown in Fig. 10, a bucket assembly, generally indicated as
300, is
attached to jet drive unit 17 at exit portion 54 so that water exiting water
exhaust 24
is operated upon by bucket assembly 300.
[0095] Bucket assembly 300 includes a bucket housing 308. Bucket
housing 308 is supported by a saddle 302 suspended from housing 13 by a
suspension arm 35. Suspension arm 35 is operatively linked to a steering rod
306.
It is understood and within the scope of the invention that any structure for
supporting bucket housing 308 may be used so long as bucket housing 308 is
supported at water exhaust 24 so as to receive water exiting water exhaust 24.
Bucket housing 308 has an entrance port 309 for receiving water exiting water
exhaust 24 and a first exhaust 311 and second exhaust 314 for causing water to
exist housing 308.
[0096] A bucket 310 is pivotally mounted on housing 308. A bucket
linkage 312 is connected to bucket 310 and a reverse cable 314, which controls
linkage 312 to rotate bucket 310 in the direction of arrow C to a first
position in which
bucket 310 is open to allow water to pass through exhaust 311 in the direction
of
arrow A. Linkage 312 also controls bucket 310 to move in the direction of
arrow B to
close first exhaust 311 (Fig. 12) and redirect the water path through second
exhaust
314 of housing 308. A directional member 316 is provided at exhaust 314 to
guide
the water in a direction substantially in the direction of arrow D back
towards housing
13.
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[0097] It should be noted that a pivoting bucket shaped member is
utilized, but any structure which selectively opens and closes water exhaust
311 may
be utilized. In a preferred embodiment, by way of example only, linkage
mechanism
312 is a bi-armed structure having a pivot, connecting one arm to the other at
a
position linked to reverse cable 314 such that movement of reverse cable 314
in the
direction of arrow E (Fig. 13) lifts the pivot point of member 312 bringing
the two
arms together (Fig. 14) shortening the distance, drawing bucket 310 toward
saddle
302 and lifting bucket 310 in the direction of arrow C. In this way, water is
allowed to
pass substantially unimpeded in the direction of arrow A, pushing housing 13
and the
boat affixed thereto in the forward direction. However, any control structure
for
moving bucket 310 may be used.
[0098] When reverse cable 314 moves in the direction of arrow F (Fig.
12), the arms of member 12 are spread (Fig. 15) rotating bucket 310 in the
direction
of arrow B closing one end of housing 308 and forcing water to exit in the
direction of
arrow D back towards the boat. The force of water exiting through opening 314
as
guided by guide member 316, pushes the boat in a reverse direction. Reverse
cable
314 is coupled to the controls of the boat by either mechanical or electro
controls.
[0099] In a preferred embodiment, the reverse cable is mounted on a
steering nozzle. This gives maximum reverse thrust control with a steering
nozzle
mounted to maintain normal reversing direction with a reverse bucket using a
standard 3-inch stroke cable. In order to keep the cable out of the water, the
vertical
operation was designed, i.e., the cable structure is mounted to cooperate with
housing 308 above jet pack unit 17 substantially away from the water. This
keeps
the entire cable, except for the stainless push/pull rod of member 312 over
the
normal water line eliminating the need for boots, seals or rust-proofing. In
order to
keep the reverse bucket from moving up and down excessively during steering,
reverse cable 314 is positioned close to the rotational point of the steering,
i.e. near
the steering cable 304, 306 at steering rod.
[0100] In a preferred embodiment, the reverse bucket, levers, bearings
and bolts are made of stainless steel and could be made of any suitable
material
such as aluminum, fiberglass, plastic or any rigid material. The stroke of
cable 314
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is preferably limited to about 3 inches and is to be hand-powered and moved in
a
maximum amount of reverse direction with a minimum effort which is achieved by
putting an additional stationary diverter, or the like, below the exhaust that
the
reverse bucket comes down to meet in the full reverse position, that, when
connected, adds additional reverse rotation to the bucket. The end of cable
314 has
a swivel (ball-type) at the saddle 302 to allow the cable to stay stationary
while
steering is being turned and also allows angle changes on any steering or
reverse
bucket position. The arms of member 12 provided at the boat are designed to
lock in
the forward position and in reverse, eliminating kickback on the cable and
allowing
the use of full thrust in reverse gear without relying on the cable to hold
the bucket in
place.
[0101] In another preferred embodiment, a simple control lever which
appears to the operator to behave as known in the art propeller engine
throttles are
preferred. Reference is now made to Figs. 31-35 in which a lever assembly,
generally indicated as 1000, for controlling direction and speed of the engine
in
accordance with the invention is provided. The desired benefit is to provide a
single
lever, which through a range of motion controls cable 314 to control both the
speed
at which the boat will travel as well as the direction.
[0102] Shift assembly 1000 includes a housing. A shift plate 1010, a
throttle plate 1200 and a lever plate 1100 disposed therebetween, and in
operative
communication with shift plate 1010 and throttle plate 1200, are mounted
within
housing 1001.
[0103] Shift plate 1010 (Fig. 31) includes a through hole 1012 forming
an axis of rotation for the plate as will be discussed later. A first arced
channel 1014
has a substantially L-shape along a surface 1016 of shift plate 1010 and
extends
through shift plate 1010. A detent 1018 is provided along the path of channel
1014
at one end thereof. An elbow region 1020 is formed along the path of channel
1014
at the other end of channel 1014. A second substantially L-shaped channel 1030
is
formed in shift plate 1010 along surface 1016. Channel 1030 extends through
shift
plate 1010. Channel 1030 includes a detent 1032 and an elbow region 1034.
Detent 1032 and elbow region 1034 are formed at opposite ends of channel 1030.
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[0104] A third channel 1040 is formed through shift plate 1010 along its
surface 1016. Channel 1040 also includes an elbow region 1042 located at a
first
end and a detent 1044 located at a second end. Like channels 1014 and 1030,
channel 1040 has one end with a detent and another end with an elbow section.
[0105] It should be noted that generally channels 1018 and 1013
substantially lie on shift plate 1010 on an opposed side of axis of rotation
1012 from
channel 1040.
[0106] Cable 314 connects shift plate 1010 to bucket 310. Cable 314 is
connected to plate 1010 at a shift section 1050. Movement of shift plate 1010
causes movement of bucket 310.
[0107] Reference is now made to Fig. 32 which shows throttle plate
1200. Throttle plate 1200 includes an axis of rotation hole 1202 extending
through
throttle plate 1200. A channel 1204 having a substantially scythe shape
extends
along a surface 1206 and through throttle plate 1200. Channel 1204 includes a
curved portion 1208 extending into a first flattened portion 1210 across an
elbow
portion 1212 from curved portion 1208. At a second opposite end of channel
1204,
is a second substantially straight portion 1214 separated from curved portion
1208
by a detent 1216 formed by the straightening of channel 1204.
[0108] A substantially U-shaped channel 1220 is formed through
throttle plate 1200 across surface 1206. A lever shaft receiving channel 1222
is
formed through throttle plate 1200 along surface 1206 and disposed
substantially
within the arms formed by U-shaped channel 1220.
[0109] Throttle plate 1200 includes an activation region 1250.
Activation region 1250 is connected to cable 720 which in turn is connected to
a
throttle of engine 16. In a simplified embodiment, a connection hole 1252 is
provided
at a distal end of region 1250 to provide maximum torque for attaching cable
720
thereto. However, any attachment method known in the art such as the use of a
coupling, buckle or the like may be used for attaching cable 720 to throttle
plate
1200. As cable 720 is pulled in the direction of arrow Y, the rpms of engine
16
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increase in turn increasing rpms of jet drive 26 and pressure and speed of the
water
flow from exhaust 24.
[0110] Reference is now made to Figs. 33 and 34 in which a lever
plate, generally indicated as 1100, is provided. An axis of rotation hole 1102
extends
through lever plate 1100. On a first surface, rollers 1104, 1106, and 1108 are
disposed on a first surface 1110 of lever plate 1100. Roller 1104 extends
outwardly
from face 1110 and is received through channel 1040 of shift plate 1010 when
lever
assembly is assembled. Similarly, roller 1106 is received within channel 1020,
and
roller 1108 is received within channel 1032.
[0111] Rollers 1110, 1112 are disposed on an opposed side 1116 of
lever plate 1100 and are positioned to be received within channels 1214 and
1220 of
throttle plate 1200. Specifically, roller 1110 is received within channel 1220
and
roller 1112 is receiving within channel 1214. As discussed below, each roller
is
adapted to slide along its respective channel.
[0112] Lever plate 1100 includes a lever 1120 for actuating lever plate
1100 when lever assembly 1000 is fully assembled. Lever assembly 1000 is
disposed in housing 1001. A first shaft (not shown) extends from housing 1001
through axis of rotation holes 1012 and 1202. A second shaft extends from
housing
1001 through axis of rotation hole 1102 of lever plate 1100. When each of
rollers
1104, 1106, 1108, 1110 and 1112 are positioned within the respective channels
in
the reverse direction it is shown in solid lines. The locked in forward
position is
shown in phantom.
[0113] For this description, as shown in the solid lines, the description
begins with the engine locked in the reverse direction at full throttle. As
lever plate
1100 is rotated in the direction of arrow W, roller 1104 travels along channel
1040 in
the direction of arrow T while roller 1108 travels in the direction of arrow U
and roller
1106 travels along channel 1018 in the direction of arrow V. Roller 1104 is
maintained in the reverse position by elbow region 1042. Without an exertion
of
force, it is difficult for roller 1104 to traverse elbow region 1042.
Similarly, it is
difficult for roller 1106 and 1108 to traverse respective detents 1018 and
1030,
maintaining those respective rollers in the reverse direction. As the roller
traverse
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the respective channels, the rollers apply a force on the respective guide
channel
rotating plate 1010 about axis of rotation 1012 having the effect of carrying
lever
plate 1100 in its rotation. This raises cable 314 which in turn raises bucket
310
diverting more and more of the water flow from exhaust 314 to exhaust 311,
initially
reducing speed in the reverse direction.
[0114] At the same time, rollers 1110 and 1112 are traveling through
their respective channels 1220, 1204. When going from reverse to forward,
roller
1110 travels about channel 1220 in the direction of arrow S while roller 1112
travels
in the direction of arrow R through channel 1204. This causes throttle plate
1200 to
rotate in the direction of arrow Q. Furthermore, because of the operation of
shift
pfate 1010 as shift plate 1010 rotates with the change of direction, lever
plate 1100 is
cammed downward relative to throttle plate 1200 its axis of rotation 1102
moves in
the direction of arrow X in effect lowering as throttle plate 1200 rotates
about axis of
rotation 1202 in effect raising throttle plate 1200. Another way of
considering it, plate
1200 rises relative to throttle 12 so that shaft plate 1200 comes in contact
with shaft
1122.
[0115] During operation, beginning in an idle position, rollers 1104,
1106, 1108 are disposed somewhere along the guide channels between the
respective elbow regions 1042, 1020, 1034 respectively and detent regions
1040,
1030, 1018. To provide forward propulsion, lever 1120 is rotated in the
direction of
arrow W causing rollers 1104, 1106, 1108 to move towards the position of the
phantom rollers in each respective guide channel. Because the rollers are
fixed to
lever plate 1100, as the rollers travel through the respective guide channels,
they
have the effect of lifting the guide channels and in turn shift plate 1010
about its axis
of rotation 1012 and lifting cable 314, in turn lifting bucket 310. This
lifting occurs
until roller 1106 traverses elbow region 1020, roller 1108 traverses elbow
region
1034 and roller 1104 traverses detent region 1034. In at least one position,
during
movement between respective elbow regions and detents, without disengaging the
engine from the jet drive, engine 16 is substantially idle, bucket 310 is at a
position
balancing jet pressure through exhausts 310 and 314.
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[0116] Once each respective roller is past the respective elbow or
detent in the forward position, shift plate 1010 no longer rotates despite
movement of
the roller. However, what has happened to throttle plate 1200 is that the
rotation of
the shift plate along with the lever has cammed the axis of rotation shaft
1122 of
lever plate 1100 in the direction of arrow X relatively raising throttle plate
1200.
Further rotation of lever plate 1100 causes movement of roller 1110 in the
direction
of arrow S and roller 1112 in the direction of arrow R which comes in contact
with
guide channels 1220 and 1208 respectively, lifting and rotating throttle plate
1200 in
the direction of arrow Q so that activation region 1250 moves in the direction
of
arrow Y causing cable 720 to move in the direction of arrow Y causing the
opening of
the throttle of engine 10. As cable 720 moves further in the direction of
arrow Y, the
engine provides more rotation to the jet drive, causing more water jet to exit
from the
water exhaust 24 increasing the speed of the boat in the forward direction. At
full
throttle, the respective rollers 1110, 1112 are shown in the position as shown
in
phantom as are rollers 1104, 1106, 1108.
[0117] As rollers 1110, 1112 are moving within their respective guide
channels 1220, 1204, roller 1106, by way of example, is moving between elbow
region 1020 and a stop end 1024 of guide channel 1018. Although traversing
that
region has no real affect on shift plate 1010, throttle plate 1200 is
experiencing
rotation. Similarly, during that same period, roller 1108 traverses a region
from
elbow region 1034 to a stop wall 1036 of guide channel 1030 and roller 1104
travels
from detent 1044 to a stop wall 1046 of guide channel 1040.
[0118] To cause reverse thrust of the engine the travel path is
reversed.
[0119] However, it should be noted that although shift plate 1000 will
rotate in the reverse direction, as shaft 1122 moves in the reverse direction
within
channel 1222 it causes throttle plate 1200 to move in the direction of arrow Q
a
second time as the rollers 1110, 1112 reverse direction, but to a lesser
extent. In
this manner, engine throttle is lower relative to the full open position so
that at least a
portion of the exiting jet stream is caught by the bucket, and at a lower
speed as it is
deflected through exhaust 314 at directional member 316.
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[0120] In a preferred embodiment, the motion of activation region 1250
in the direction of arrow Y moves about 1-3/4 inches when in the forward
orientation;
it moves about 5/8 inch in reverse. It should be noted that in a preferred
embodiment for control purposes, bucket 310 is never entirely lowered to
prevent an
excessively fast or quick reverse movement of the engine in the boat.
Furthermore,
idling occurs somewhere between a stroke length of 5/8 inch and 1/-3/4 inch
where
the reverse thrust is balanced with the forward thrust.
[0121] To the user, operation of the lever will be continuous and
seamless. As the lever is moved between a first position and second position,
shifting of the bucket occurs to reduce the speed in the forward direction as
a portion
of the jet stream is deflected in the reverse direction through exhaust 314.
Continued shifting from a second to a third direction reduces the throttle,
increasing
the speed in the forward direction. A fourth position, somewhere between the
second and third position is that position where the shift plate has been
rotated
sufficiently to balance the thrust in the forward and reverse directions at
the jet drive
unit. This idles the boat without disengaging the engine.
[0122] When operating in the reverse direction, at first the boat is
slowed down as shifting occurs between the third and second position and
throttle
plate 1200 is rotated to reduce the pull on cable 720 from, in a preferred and
non-
limiting example, 1-3/4 inches to 5 inches. Bucket 310 becomes lowered as the
lever is shifted from the second to the first position, causing change of
direction of
the boat. A single lever controls speed and direction.
[0123] By utilizing an outboard motor, so that exhaust portion 54 of jet
drive unit 17 is distanced away from hull 12 of boat 11, the water jet exiting
housing
308 through exhaust opening 314 does not substantially interact with hull 11.
As a
result, the hull does not substantially interfere with the exiting jet stream
and the
efficiency of the jet engine when driving in reverse is greatly increased.
[0124] Reference is now made to Figs. 16-18. Steering rod 306 is
pivotally connected to bucket housing 308. Steering rod 306 is also coupled to
hand
controls on boat 11 so that a driver may control steering. Through movement of
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steering rod 306, bucket assembly 308 is rotated in the direction of arrow G
to
produce a left turn or in the direction of arrow H to produce a right turn.
[0125] Top 30 of housing 13 is removable from the housing main part
31, as shown in FIG. 3. The housing 13 with the engine 16 and the jet drive
unit 17
mounted therein may be attached to the transom 12 of the hull 11 with a pair
of
brackets 32. Brackets 32 allow the housing 13 to be mounted substantially even
with
the bottom of the boat hull or higher than the bottom of the boat hull so as
to reduce
ingression of debris and damage to wildlife.
[0126] Reference is now made to Figs. 19-23 in which a preferred
embodiment of the engine housing is discussed. In a preferred embodiment,
housing 313 has a convex lower surface 315. In a preferred embodiment, the
lower
surface of housing 313 is substantially bowl-shaped. In the preferred, but not
limiting
embodiment, the convex surface is disposed between 1 inch higher than a bottom
of
the hull 11, or 2 inches lower than the bottom of hull 11. This significantly
reduces
cavitation in jet drive unit 17.
[0127] As hull 11 of a boat passes through the water, air becomes
mixed in the water as is noticed in any foaming wake. Air in the water as it
passes
through jet unit 17 causes cavitation, which reduces the power of outboard
propulsion unit 10. However, by providing a rounded, convex lower surface 315
at a
trailing position from hull 11, a high-pressure force area is provided along
the
submerged bottom surface 315 of housing 313. Furthermore, the water assumes a
shape, as shown in Fig. 22, as it moves across housing 313. As the water moves
relatively in the direction of arrow I, its path is widened around housing 313
and then
narrowed as it travels across housing 313. This is because a high-pressure
area is
formed along the surface of housing 313 as it moves through the water relative
to the
surrounding water.
[0128] Because air is less dense and lighter than the water which
contains it, it either escapes in the direction of arrow J (Fig. 19) through a
low
pressure area K located between hull 11 and trailing housing 313 or moves to
the
sides of housing 313 as shown in Fig. 23. In effect, air bubbles are pushed
from the
water by the high pressure. Air bubbles 320 seek the low-pressure area at the
sides
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of housing 313, allowing the remaining water to proceed directly to inlet 22.
The
rounded shape of housing 313 also maintains water close to it in the direction
of
arrow L more efficiently guiding the water from which the bubbles have escaped
towards inlet 22. "Solid" water is what is provided into the inlet, i.e. water
from which
substantially all air bubbles have been removed, preventing cavitation.
[0129] It should be noted that the water traveling in the direction of
arrow L tends to travel faster than the water away from housing 313 so that it
clings
to inlet 22. It also widens in its shape when under pressure as shown in Fig.
22
providing more squeezing of air bubbles out of the desired water stream. As
seen in
Fig. 23, bubbles 320 seek their own escape as they are squeezed out, allowing
a
purer stream of water 324 to enter inlet 22 of jet unit 17.
[0130] In a preferred embodiment, the width of the convex shape of
housing 313 at the width M is greater than a width N of inlet 22. In this way,
it is
assured that the water 324 flowing towards inlet 22 is at the center of the
high-
pressure region, further ensuring the removal of the air bubbles 320 from the
water.
In a preferred embodiment, the width of a convex portion of housing 313 is
about
120% the width of inlet 22. Again, bottom surface 315 may be positioned, in a
preferred, but non-limiting example, from one inch above a bottom 317 of hull
11 to
two inches below bottom 317 of hull 11. As can be seen, when bucket assembly
300
is substantially orthogonal with hull 11, the boat is driven forward. When
bucket
assembly 300 forms an angle of less than 90 degrees (on either side) with hull
11,
the boat is turned.
[0131] However, as shown in Fig. 20 there is some overhang of the
engine housing 313 relative to hull 11. These overhang regions 370 catch the
water
and provide drag. In order to maintain the relative width of housing 313, and
reduce
drag, a housing 380 is stepped sufficiently (Figs. 28-30) to maintain the
overall width
of housing 313 while being narrow at those positions adjacent hull 11 to
prevent
overhang. Housing 380 includes a first convex portion 382, having a centerline
384.
Convex portion 382 is curved in a direction extending from the hull of the
boat in a
direction away from the boat. Furthermore, the pitch of convex section 382
increases away from centerline 384. The pitch may be as steep as about 26 .
The
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convex portion further aids in keeping air bubbles away from the intake
reducing
cavitation.
[0132] Only one side of housing 380 shall be described because in a
preferred embodiment, housing 380 is substantially symmetrical about
centerline
384. Extending from centerline 384, a step portion 386 forms a shelf portion
388. A
pocket 390 is formed as a further step within step portion 386. Pocket 390
includes
a sidewall 393, a second wall 396, and a step 384 formed therebetween.
[0133] An exhaust 397 for venting engine 400 is provided within pocket
390. Because pocket 390 is surrounded on at least two sides, one wall 393
being
that portion of pocket 390 closest to centerline 384, air and gas escaping
through
exhaust 397 are deflected away from centerline 384 and are deflected towards
the
side of housing 380 by the step walls 386, 393 particularly when moving in a
reverse
direction. Therefore, the bubbles would not reenter the intake of the jet
reducing
cavitation.
[0134] In any event, the width should be sufficient so that the bubbles
320 are diverted sufficiently wide as shown in Fig. 21a, they are deflected
away from
a sufficient radius of intake 22 so as not to interfere or enter inlet 22,
whether inlet 22
is in line with hull 11, or during left and right turns (Fig. 21 b, 21 c).
[0135] Hull 11 has the main fuel tank 33 mounted therein having a fuel
tank inlet 34 and a fuel line 35 extending therefrom through the transom 12
and to a
quick disconnect 36 where it can be quickly coupled or decoupled from an
internal
fuel line 37 located inside the housing 13. The fuel line 37 enters an
auxiliary internal
fuel tank 38 which has a fuel line 40 connected thereto which is connected to
a fuel
pump 41 for pumping the fuel from the auxiliary fuel tank 38 and from the main
fuel
tank 33 and into the fuel line 42 where it is fed directly into the fuel
injectors of the
engine 16. A fuel return line 43 is connected to the auxiliary fuel tank 38
and to a de-
aerator 44 having a bleed top 45 and having a return fuel. line 46 from the
engine 16
fuel injectors.
[0136] A battery 47 is shown mounted within the housing 13 and is
connected through a ground line 48 to the jet drive unit 17. The engine and
drive unit
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are controlled through electrical control lines 50 which are connected through
a quick
electrical connector 51 which is a waterproof connector mounted through the
housing 13 and to the engine 16 and clutch unit 27 to control the operation of
the
outboard jet drive unit.
[0137] The rear wall 21 of the housing 13 has a tow bracket 52 attached
thereto for attaching a line.
[0138] As seen in FIG. 4, the main fuel tank 33 having the filler cap 34 is
connected through the fuel line 35 to the auxiliary tank 38 having an
auxiliary tank
opening 55 and having the fuel pump 41 connected through the fuel line 40 from
the
auxiliary tank 38 and through a line 42 to the fuel injectors and back through
a de-
aerator 44 from the fuel injectors and through the fuel line 43 back to the
auxiliary
fuel tank 38. A breather 45 is connected to the dc-aerator unit 44.
[0139] In operation, the hull 11 has the fuel tank 33 installed therein
along with all the controls and sensors. The controls and sensors are
connected
through the multi-line electrical conductor 50 while the fuel tank is
connected through
the fuel line 35 through the transom 12. The outboard drive unit 10 can then
be
attached to the brackets 32 on the transom 12 in a position to align the
bottom of the
unit with the bottom of the hull 23. In a preferred embodiment, brackets 32
may be
shock absorbers to further reduce vibration to engine 16 and jet drive unit
17. Then,
merely attaching the quick connect couplings 36 to the fuel line, connects the
fuel
lines to the outboard jet drive while connecting the quick coupling 51
connects the
electrical controls. If the unit has to be removed for any reason, it can be
disconnected from the brackets 32 by disconnecting the quick couplings 36 and
51
to remove the entire unit. The outboard jet drive unit 10 is made by
constructing a
waterproof housing 13 mounting the jet drive unit 17 therein underneath the
platform
14 and mounting the engine 16 to the engine mounts 15 on the platform 14 and
then
connecting the belt drive clutch mechanism 27 between the engine 16 and the
jet
drive unit 17 through the pulley 28.
[0140] Because in a preferred embodiment engine 16 and jet unit 17
ship as a unit, the jet size to use is known. Smaller boats usually forego the
reduction and just use a jet, which is too small, operated at engine speed.
For those
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who wish to use a larger jet and a reduction, a transmission must be used.
This is an
extra cost an extra layer of complexity and an extra gearing change which robs
the
engine's efficiency. Furthermore, although transmissions could be made to
match a
particular engine to a particular jet, the current volumes of production make
this cost
prohibitive.
[0141] Another key advantage of the present invention is that the gear
ratio can be changed just by changing one or both gears. As a result, any
engine
power can be matched to a desired RPM in a single jet design. With four or
five
different jets, a range of engines from 35 HP to 2000 HP can be covered. Thus,
one
jet can now be used with engines from 50 HP to 400 HP. This is a huge
advantage in
that different jets do not need to be designed for different engines.
[0142] Preferably, housings 13, 201, 206 are sealed mostly to create
buoyancy and to protect the engine from corrosion or damage; however,
prevention
of oil and anti-freeze leaks to the outside (surrounding water) is a side
benefit. The
leaks from the engine could be isolated by providing a pan below the engine
with
separate drainage.
[0143] Notwithstanding the above, it should be appreciated that, in
accordance with the present invention, in certain models, water may enter and
exit
the heat exchanger and intercooler through holes drilled specifically for that
purpose;
however, these holes are sealed to prevent water from entering or leaking into
the
engine compartment. In addition, water may enter into the exhaust ports.
However,
the engine is far enough above the water line to prevent water from rising
high
enough to enter the engine or engine compartment. Water also may enter the jet
intake and exits the jet nozzle; this water is prevented from entering the
engine
compartment by sealing the hole around the jet impeller shaft. There may also
be air
intake vents in the lid in which water may enter. These are made with baffles
designed to drain any water, which gets in out through the lid before it gets
into the
engine compartment.
[0144] While the bottom of the housing may be mounted in any suitable
position, such as about even with or higher than the bottom of the boat hull,
any
position around or even with the bottom of the boat is workable. In a
preferred
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position, the bottom of the housing is at about an inch below the bottom of
the boat
hull on boats to ensure or maximize the amount of clean water that enters the
water
intake of the jet drive unit. In addition, this position will reduce
ingression of debris
and damage to wildlife. It of course should be understood that this position
may very
depending upon the configuration of the bottom. of the boat. It is believed
that this is
the optimum position, because the jet intake is built into the housing.
Nevertheless,
the bottom center of the boat is the optimum depth position for the water
intake in the
preferred embodiment.
[0145] In a preferred embodiment, marine propulsion unit 10's steering
nozzles, exhaust of bucket assembly 300, are generally about 30 inches or more
behind boat transom 12. This provides excellent steering leverage and, with a
large
diameter having water jet 313 moving large amounts of water, it provides crisp
steering response and solid tracking with very little correction. The steering
control
pressures of marine propulsion unit 10 are very light and do not require power
steering for comfortable boating.
.[0146] Because of bucket assembly 300, propulsion unit 10 provides the
capability of "putting on the brakes". When propulsion unit 10 is shifted into
reverse,
all the power of the engine and water jet are applied to stop and reverse the
boat.
Tests on a 5,000-pound boat equipped with a propulsion unit 10 as described
herein
show that the boat could be stopped completely within two boat lengths from 30
mph
with ease.
[0147] The recommended procedure to stop outboard propulsion unit 10
is to reduce the engine RPM by about 50 percent and shift into reverse. If
desired,
the engine RPM can be increased. In an emergency, the boat can be shifted into
reverse directly at any power setting, but that may injure the boat
passengers.
[0148] Useable space inside a boat is usually at a premium. The
outboard propulsion system, in accordance with the invention, and the
traditional
outboard engines have a distinct advantage over inboard/outboard and inboard
systems that require valuable space inside the boat for engines and essential
equipment. Even traditional outboards are at a disadvantage compared to the
propulsion unit 10 because they generally require space inside the boat when
in the
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tilted up profile. Also, many outboards require a notch in the transom to
achieve the
correct propeller depth requiring a second "transom" inside the boat to
prevent
following seas from swamping the boat. That space is lost boat space.
[0149] Propulsion unit 10 requires no space inside the boat for any of its
components. The increase in space inside the boat is available for any use,
e.g., for
passengers, bait wells, fish holds, and even for lounging decks.
[0150] Because engine 16 is mounted on high quality vibration isolators
inside the fiber glass shell and housing 13 is mounted on the boat transom
using a
second system of vibration isolators, an exceptional and unexpected level of
quiet
and comfort is provided. As a result, the boat ride is more comfortable and
less tiring.
[0151] Internal combustion engines get hot when running. That engine
heat is handled several ways in a boat. The engine water-cooling system is
designed
to remove a considerable amount of that heat, but that system operates at
about 160
to 220 degrees Fahrenheit to insure that the engine operates correctly. The
balance
of the heat is released in convection, radiated into the air in the engine
compartment.
This heat can make it quite uncomfortable in the area of the engine
compartment,
especially on a hot day. This problem exists with any inboard or UO drive
configuration. Ventilating fans and insulation can reduce the problem to a
degree,
but it is difficult to eliminate.
[0152] Outboard marine engines are mounted behind the transom
behind the boat. Any heat from these engines that is not carried overboard by
the
water-cooling system is released into the air behind the boat. This gives all
outboard
engines a distinct advantage over inboard mounted engines.
[0153] Propulsion unit 10 has an added advantage because it has the
engine mounted in a sealed box and the air inside the box is normally ingested
into
the engine and goes out the exhaust in the water. It is very unlikely that a
passenger
will feel any warming of the air in the boat caused by the propulsion unit.
[0154] As a result of sealing housing 313, propulsion unit 10 is uniquely
designed with self-buoyant capability. Because the housing is sealed, it
provides
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flotation. Indeed, in a preferred embodiment, at approximately 1 foot of
draft, it floats
about 250 Ibs, at approximately 1.5 foot (18 inches) of draft, it floats about
500 Ibs,
and at approximately 2 feet of draft, it floats about 850.Ibs (approximately
the total
weight of the marine propulsion system). This is a significant feature and
advantage
to any boat and especially valuable to smaller boats with low freeboard
dimensions.
[0155] Some of the new four-cycle outboards are quite heavy and
cannot be used on some existing boats because the extra weight causes the
scuppers to be submerged. At least one boat manufacturer had to redesign their
boat to accommodate these heavy engines. Inboard/outboard and inboard systems
depend solely on the boat to provide their flotation. The weight of the
propulsion
system, in all of these instances, reduces the boats' cargo and passenger
carrying
capability.
[0156] Because of the buoyancy of housing, propulsion unit 10 allows
boats to uniquely have more weight carrying capacity and, as a further
benefit, more
useable space inside the boat is available.
[0157] Propulsion unit 10 preferably uses a stainless steel water jet
impeller to supply the seawater to the heat exchanger for engine cooling. If
the
impeller is turning, there is water for the cooling function. Even if the
stainless steel
impeller were severely damaged, there would be enough water flow to move the
boat and provide engine cooling.
34
