U.S. patent application number 11/041569 was filed with the patent office on 2006-07-27 for drive system for a marine vessel.
Invention is credited to John Fiorenza, David Rose, Tim Vetta.
Application Number | 20060166573 11/041569 |
Document ID | / |
Family ID | 36697464 |
Filed Date | 2006-07-27 |
United States Patent
Application |
20060166573 |
Kind Code |
A1 |
Vetta; Tim ; et al. |
July 27, 2006 |
Drive system for a marine vessel
Abstract
A drive system for a marine vessel. The drive system includes a
drive shaft that is rotatable about a drive axis and a motor
interconnected with the drive shaft and including a rotor that
defines a motor axis that is substantially coaxial with the drive
axis. The motor is operable at a motor speed to rotate the drive
shaft. An engine has an output shaft interconnected with the drive
shaft and is operable at an engine speed to rotate the drive shaft.
The output shaft defines an engine axis that is substantially
coaxial with the motor axis. A clutch is operable to inhibit the
transfer of torque from the motor to the engine when the engine
speed is less than a predetermined engine speed without
disconnecting the output shaft from the drive shaft. A tiller arm
includes a speed control. The speed control is operable to control
the engine speed and to control the motor speed.
Inventors: |
Vetta; Tim; (Milwaukee,
WI) ; Fiorenza; John; (Slinger, WI) ; Rose;
David; (New Berlin, WI) |
Correspondence
Address: |
MICHAEL BEST & FRIEDRICH, LLP
100 E WISCONSIN AVENUE
MILWAUKEE
WI
53202
US
|
Family ID: |
36697464 |
Appl. No.: |
11/041569 |
Filed: |
January 24, 2005 |
Current U.S.
Class: |
440/75 |
Current CPC
Class: |
B63H 20/12 20130101;
B63H 20/20 20130101 |
Class at
Publication: |
440/075 |
International
Class: |
B63H 20/14 20060101
B63H020/14 |
Claims
1. A drive system for a marine vessel, the drive system comprising:
a drive shaft rotatable about a drive axis; a motor including a
rotor that defines a motor axis, the drive shaft rotating in
response to rotation of the rotor at a motor speed; an engine
including an output shaft, the drive shaft and rotor rotating in
response to operation of the engine at an engine speed; a clutch
operable to inhibit the transfer of torque from the motor to the
engine and to facilitate the transfer of torque from the engine to
the motor and to the drive shaft without manipulating any
mechanical connection between the motor, the engine, and the drive
shaft; and a tiller arm including a speed control, the speed
control operable to control the engine speed and to control the
motor speed.
2. The drive system of claim 1, wherein the motor includes a
stator, and wherein the rotor is spaced axially from the stator to
define an axial air gap.
3. The drive system of claim 1, wherein the motor rotor is
interconnected with the drive shaft such that the motor rotor
rotates in unison with the drive shaft.
4. The drive system of claim 1, wherein the clutch connects the
output shaft and the motor rotor.
5. The drive system of claim 1, wherein the clutch includes a
clutched position and a declutched position and wherein the clutch
is in the declutched position when the engine speed is below a
predetermined speed and is in the clutched position when the engine
speed is above the predetermined speed.
6. The drive system of claim 1, wherein the clutch includes a
centrifugal clutch.
7. The drive system of claim 1, wherein the clutch includes a
roller clutch.
8. The drive system of claim 1, wherein at least a portion of the
clutch is formed as part of the rotor.
9. The drive system of claim 1, further comprising a switch having
a first position in which the engine is operable, and having a
second position in which operation of the engine is inhibited but
the motor is operable.
10. The drive system of claim 9, wherein the engine includes an
engine ignition that is grounded when the switch is in the second
position.
11. The drive system of claim 9, wherein the engine operates when
the switch is in the first position to rotate the motor rotor and
the drive shaft, the rotation of the motor rotor delivering a flow
of electrical current to an electrochemical energy source, and
wherein when the switch is in the second position the
electrochemical energy source delivers a flow of electrical current
to the motor such that the motor operates to rotate the drive
shaft.
12. The drive system of claim 9, wherein the speed control is
operable to control the engine speed when the switch is in the
first position and to control the motor speed when the switch is in
the second position.
13. The drive system of claim 9, further comprising a power
conditioner interconnecting the motor and an electrochemical energy
source, the power conditioner operable to deliver conditioned power
to the electrochemical energy source when the switch is in the
first position and to deliver an amount of conditioned power to the
motor when the switch is in the second position.
14. The drive system of claim 1, wherein the speed control includes
a potentiometer.
15. A drive system for a marine vessel, the drive system
comprising: a drive shaft rotatable about a drive axis to propel
the vessel; a motor including a rotor coupled to the drive shaft,
the motor operable at a motor speed to rotate the drive shaft; an
engine including an engine ignition, the engine coupled to the
motor rotor and operable at an engine speed to rotate the rotor and
the drive shaft; an electrochemical energy source; a controller
operable to control the flow of electrical power between the
electrochemical energy source and the motor; a clutch disposed
between the motor rotor and the engine, the clutch operable both to
inhibit the transfer of torque from the motor to the engine and to
facilitate the transfer of torque from the engine to the motor and
to the drive shaft without decoupling the engine and the motor
rotor; and a switch having a first position in which the engine is
operable, and having a second position in which the engine ignition
is grounded but the motor is operable.
16. The drive system of claim 15, wherein the motor includes a
stator, and wherein the rotor is spaced axially from the stator to
define an axial air gap.
17. The drive system of claim 15, wherein the motor rotor is
interconnected with the drive shaft such that the motor rotor
rotates in unison with the drive shaft.
18. The drive system of claim 15, wherein the engine includes an
engine drive shaft and the clutch connects the engine drive shaft
and the motor rotor.
19. The drive system of claim 15, wherein the clutch includes a
centrifugal clutch.
20. The drive system of claim 15, wherein the clutch includes a
roller clutch.
21. The drive system of claim 15, wherein at least a portion of the
clutch is formed as part of the rotor.
22. The drive system of claim 15, wherein the engine operates when
the switch is in the first position to rotate the motor rotor and
the drive shaft, the rotation of the motor rotor delivering a flow
of electrical current to the electrochemical energy source, and
wherein when the switch is in the second position the
electrochemical energy source delivers a flow of electrical current
to the motor such that the motor operates to rotate the drive
shaft.
23. The drive system of claim 15, wherein the controller is
operable to deliver conditioned power to the electrochemical energy
source when the switch is in the first position and to deliver an
amount of conditioned power to the motor when the switch is in the
second position.
24. The drive system of claim 15 further comprising a tiller arm
including a speed control, the speed control operable to control
the engine speed when the switch is in the first position and to
control the motor speed when the switch is in the second
position.
25. The drive system of claim 24, wherein the speed control
includes a motor speed adjustment member that is movable between a
first position and a second position to provide a signal to the
controller to vary the amount of electrical power delivered to the
motor.
26. The drive system of claim 25, wherein the motor speed
adjustment member includes a potentiometer.
27. A drive system for a marine vessel, the drive system
comprising: a drive shaft rotatable about a drive axis; a motor
including a stator and a rotor that defines a motor axis, the rotor
offset from the stator a distance along the motor axis to define an
axial air gap, the drive shaft rotating in response to rotation of
the rotor at a motor speed; an engine including an output shaft,
the drive shaft and rotor rotating in response to operation of the
engine at an engine speed; and a clutch operable to inhibit the
transfer of torque from the motor to the engine and to facilitate
the transfer of torque from the engine to the motor and to the
drive shaft without manipulating any mechanical connection between
the motor, the engine, and the drive shaft.
28. The drive system of claim 27, wherein the motor rotor is
interconnected with the drive shaft such that the motor rotor
rotates in unison with the drive shaft.
29. The drive system of claim 27, wherein the clutch connects the
output shaft and the motor rotor.
30. The drive system of claim 27, wherein the clutch includes a
clutched position and a declutched position and wherein the clutch
is in the declutched position when the engine speed is below a
predetermined speed and is in the clutched position when the engine
speed is above the predetermined speed.
31. The drive system of claim 27, wherein the clutch includes a
centrifugal clutch.
32. The drive system of claim 27, wherein the clutch includes a
roller clutch.
33. The drive system of claim 27, wherein at least a portion of the
clutch is formed as part of the rotor.
34. The drive system of claim 27, further comprising a switch
having a first position in which the engine is operable, and having
a second position in which operation of the engine is inhibited but
the motor is operable.
35. The drive system of claim 34, wherein the engine includes an
engine ignition that is grounded when the switch is in the second
position.
36. The drive system of claim 34, wherein the engine operates when
the switch is in the first position to rotate the motor rotor and
the drive shaft, the rotation of the motor rotor delivering a flow
of electrical current to an electrochemical energy source, and
wherein when the switch is in the second position the
electrochemical energy source delivers a flow of electrical current
to the motor such that the motor operates to rotate the drive
shaft.
37. The drive system of claim 34, further comprising a tiller arm
including a speed control, the speed control operable to control
the engine speed when the switch is in the first position and to
control the motor speed when the switch is in the second
position.
38. The drive system of claim 37, wherein the speed control
includes a motor speed adjustment member movable between a first
position and a second position, the motor speed adjustment member
providing a signal to the power conditioner to vary the amount of
conditioned power delivered to the motor.
39. The drive system of claim 38, wherein the speed adjustment
member includes a potentiometer.
40. The drive system of claim 34, further comprising a power
conditioner interconnecting the motor and an electrochemical energy
source, the power conditioner operable to deliver conditioned power
to the electrochemical energy source when the switch is in the
first position and to deliver an amount of conditioned power to the
motor when the switch is in the second position.
Description
BACKGROUND
[0001] The present invention relates generally to a drive system
for a marine vessel. More particularly, the present invention
relates to a hybrid drive system for a marine vessel.
[0002] Marine vessels (e.g., boats, inflatable rafts, canoes,
sailboats, personal watercraft, and the like) generally include an
engine that turns a propeller to propel the vessel through the
water. Generally, the engine is an internal combustion engine that
combusts fuel to propel the vessel. Many boats employ an outboard
engine, which mounts to the transom of the vessel and extends into
the water. The engine turns the propeller in the water to generate
propulsion. Other vessels may employ inboard engines in which the
engine is disposed within the boat and only a portion of a
driveshaft and the propeller extend into the water. Still other
vessels use an inboard-outboard engine, which combines certain
aspects of inboards and outboards. Generally, the engine is
disposed within the boat and a lower unit containing a drive shaft
and various gears is disposed outside the boat.
[0003] While engines are well-suited to propelling vessels in the
water, there are restrictions on the use of engines on some bodies
of water. In addition, sportsmen often use an electric motor to
quietly move their vessel into a fishing or hunting area.
Unfortunately, these electric motors are separate from the main
engine, thus requiring their own control system as well as their
own mechanical systems (e.g., lower unit extending into the water,
propeller, driveshaft, drive gears, and the like). In addition, the
electric motors are often visually unappealing and provide
additional obstructions for fishing and occupy additional space
within the vessel.
SUMMARY
[0004] The present invention provides a drive system for a marine
vessel. The drive system includes a drive shaft that is rotatable
about a drive axis, and an electric motor interconnected with the
drive shaft and including a rotor that defines a motor axis that is
substantially coaxial with the drive axis. The motor is operable at
a motor speed to rotate the drive shaft. An engine has an output
shaft interconnected with the drive shaft and is operable at an
engine speed to rotate the drive shaft. The output shaft defines an
engine axis that is substantially coaxial with the motor axis. A
clutch is operable to inhibit the transfer of torque from the motor
to the engine when the engine speed is less than a predetermined
engine speed without disconnecting the output shaft from the drive
shaft. A tiller arm includes a speed control. The speed control is
operable to control the engine speed and to control the motor
speed.
[0005] In another aspect, the invention provides a drive system for
a marine vessel. The drive system includes a drive shaft that is
rotatable about a drive axis to propel the vessel, and a motor that
includes a rotor coupled to the drive shaft. The motor is operable
at a motor speed to rotate the drive shaft. An engine that includes
an engine ignition is coupled to the motor rotor and is operable at
an engine speed to rotate the rotor and the drive shaft. The drive
system also includes an electrochemical energy source (e.g., a
battery or fuel cell) and a controller that is operable to control
the flow of electrical power between the electrochemical energy
source and the motor. A clutch is disposed between the motor rotor
and the engine. The clutch has a declutched position in which the
transfer of torque from the motor to the engine is inhibited
without decoupling the engine and the motor rotor. A switch has a
first position in which the engine is operable and a second
position which inhibits operation of the engine but enables the
motor to be operable. The drive system also includes a tiller arm
having a speed control. The speed control is operable to control
the engine speed when the switch is in the first position and to
control the motor speed when the switch is in the second position.
A switch has a first position in which the engine is operable, and
a second position in which the engine ignition is grounded but the
motor is operable.
[0006] In still another aspect, the present invention provides a
drive system for a marine vessel. The drive system includes a drive
shaft that is rotatable about a drive axis. A motor includes a
stator and a rotor that defines a motor axis. The rotor is offset
from the stator a distance along the motor axis to define an axial
air gap. The drive shaft rotates in response to rotation of the
rotor at a motor speed. An engine includes an output shaft. The
drive shaft and rotor rotate in response to operation of the engine
at an engine speed. A clutch is operable to inhibit the transfer of
torque from the motor to the engine and to facilitate the transfer
of torque from the engine to the motor and to the drive shaft
without manipulating any mechanical connection between the motor,
the engine, and the drive shaft.
[0007] Additional features and advantages will become apparent to
those skilled in the art upon consideration of the following
detailed description of preferred embodiments exemplifying the best
mode of carrying out the invention as presently perceived.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The detailed description particularly refers to the
accompanying figures in which:
[0009] FIG. 1 is a perspective view of a marine vessel with a
hybrid outboard motor;
[0010] FIG. 2 is a partially broken away schematic view of the
hybrid outboard motor of FIG. 1;
[0011] FIG. 3 is an enlarged schematic view of a portion of the
hybrid outboard motor of FIG. 1;
[0012] FIG. 4 is a perspective view of a one-way bearing;
[0013] FIG. 5 is a top view of a centrifugal clutch;
[0014] FIG. 6 is an enlarged schematic illustration of the motor
portion of FIG. 1 including a centrifugal clutch;
[0015] FIG. 7 is an enlarged schematic illustration of the motor
portion of FIG. 1 including a one-way bearing;
[0016] FIG. 7a is an enlarged schematic illustration of the motor
portion of FIG. 1 including another arrangement of the one-way
bearing;
[0017] FIG. 8 is a schematic diagram of a control system for the
hybrid motor of FIG. 1;
[0018] FIG. 9 is schematic diagram of another control system for
the hybrid motor of FIG. 1; and
[0019] FIG. 10 is a schematic diagram of another control system for
the hybrid motor of FIG. 1.
[0020] Before any embodiments of the invention are explained, it is
to be understood that the invention is not limited in its
application to the details of construction and the arrangements of
components set forth in the following description or illustrated in
the following drawings. The invention is capable of other
embodiments and of being practiced or of being carried out in
various ways. Also, it is to be understood that the phraseology and
terminology used herein is for the purpose of description and
should not be regarded as limiting. The use of "including,"
"comprising," or "having" and variations thereof is meant to
encompass the items listed thereafter and equivalence thereof as
well as additional items. The terms "connected," "coupled," and
"mounted" and variations thereof are used broadly and encompass
direct and indirect connections, couplings, and mountings.
DETAILED DESCRIPTION
[0021] With reference to FIG. 1, a marine vessel 10, in the form of
a boat, is illustrated as including an outboard engine 15. Vessels
10 of this type are often used on small lakes and streams for
fishing or other activities. The outboard engine 15 provides power
to move the marine vessel 10 and rotates about a steering axis to
steer the vessel 10. While the present invention will be described
in detail as it applies to an outboard engine 15 similar to that of
FIG. 1, one of ordinary skill will realize that the invention has
other applications. For example, other types of boats or vessels
(e.g., canoes, sailboats, runabouts, personal watercraft, etc.)
could employ the present invention. Furthermore, the present
invention could be used with an inboard engine or an
inboard-outboard engine. As such, the description of the invention
as it applies to an outboard engine 15 should not be read as
limiting the invention to only outboard engines 15.
[0022] Turning to FIG. 2, the outboard engine 15 of FIG. 1 is shown
schematically with a portion of an exterior housing 20 broken away
to show the internal components. The engine 15 includes an upper
portion 25 that houses two prime movers, and a lower unit 30 that
supports a propeller 35 and contains forward/reverse gearing 40 and
a portion of a drive shaft 45. The lower unit 30 extends below the
water line 50 to allow rotation of the propeller 35 to propel the
vessel 10.
[0023] The prime movers disposed in the upper portion 25 of the
engine are best shown in FIG. 3 and include an internal combustion
engine 55 and an electric motor 60. The electric motor 60 is
positioned beneath the internal combustion engine 55 and is
interconnected with the drive shaft 45. The internal combustion
engine 55 also interconnects with the drive shaft 45. Thus,
operation of the electric motor 60 or the internal combustion
engine 55 can produce rotation of the drive shaft 45 and propeller
to propel the vessel 10. In most constructions, the internal
combustion engine 55 is air-cooled. However, some constructions may
employ a water-cooled engine. Water is drawn from the body of water
the vessel is operating on and is directed up the lower unit 30 to
the engine. After cooling the engine, the water returns down the
lower unit 30 and flows back into the body of water.
[0024] The electric motor 60, shown in FIG. 3, is a brushless DC
axial air gap motor that includes a stator 65 and a rotor 70, and
may include a motor controller 75 (shown in FIG. 9). A motor 60 of
this type is sold by Briggs & Stratton Corporation of
Milwaukee, Wis. under the trademark ETEK. While other types of
motors could be employed, the motor 60 described herein occupies a
compact space and provides the horsepower and torque desired to
propel the vessel 10 through the water.
[0025] The stator 65 fixedly attaches to the exterior housing 20 of
the outboard engine 15 such that it is substantially coaxial with
the drive shaft 45. The stator 65 includes a plurality of poles
that each include windings that can be selectively energized to
produce the necessary magnetic fields for motor operation. The
stator 65 also includes a substantially cylindrical opening 80
through its center that allows for the passage of a motor shaft, if
employed, or the drive shaft 45.
[0026] The rotor 70 is a substantially disk-shaped component that
supports a plurality of permanent magnets 85. The rotor 70 is
supported above the stator 65 with the permanent magnets 85 axially
spaced from the stator windings such that as the stator windings
are energized, a magnetic field is produced that interacts with the
permanent magnets 85 of the rotor 70 to produce rotation. The
stator windings are energized and de-energized in a particular
sequence, at a particular rate, and with a particular polarity to
produce rotation of the rotor 70 in a desired direction at a
desired speed.
[0027] In most constructions, a thrust bearing 90 is disposed
between the rotor 70 and the stator 65 to both position the rotor
70 relative to the stator 65 and to support the axial load (the
weight) of the rotor 70 during motor operation. FIGS. 3, 6, and 7
schematically illustrate a thrust bearing 90 that is suited to the
task of supporting the rotor 70. Other constructions may apply
other suitable means to separate the rotor 70 from the stator 65.
For example, one or more bearings generally support the drive shaft
45 for rotation. One of these bearings could include
thrust-carrying capability such that the bearing supports the
thrust load of the rotor 70. In these constructions, the drive
shaft 45 supports the generator rotor 70 in the desired axial
position without the need for a separate thrust bearing 90 between
the rotor 70 and the stator 65.
[0028] The internal combustion engine 55, illustrated in FIG. 3,
includes a housing 95 that supports one or more piston/cylinder
arrangements that operate to rotate a crankshaft, as is well known
in the engine art. The number of piston/cylinder arrangements
employed is largely a function of the power required for the
particular application. The engine 55 combusts an air/fuel mixture
to rotate the crankshaft and produce shaft power. The crankshaft
extends from the housing to define an output shaft 100. In most
constructions, the output shaft 100 extends vertically from the
bottom of the housing 95 along an engine axis A-A. The engine 55 is
similar to known internal combustion engines and as such will not
be described in detail.
[0029] Support members 103 engage the engine 55 and the exterior
housing 20 to support the engine 55 in its desired operating
position above the electric motor 60. As illustrated in FIGS. 2 and
3, the support members 103 resemble columns. The actual form of the
support members 103 is unimportant so long as they are capable of
supporting the engine 55 above the motor 60. The support members
generally provide no alignment function but rather allow the engine
55 to move as needed to properly align the output shaft 100
relative to the drive shaft 45. For example, in one construction a
platform is supported by the stator 65 and is shaped to support the
engine 55.
[0030] The output shaft 100 extends from the bottom of the engine
55 and engages a clutch mechanism 105 between the engine 55 and
motor 60. FIGS. 2, 3, 5 and 6 illustrate one possible clutch
mechanism 105 in the form of a centrifugal clutch 110. The
centrifugal clutch 110 includes an outer drum 115, a biasing member
120 (e.g., one or more springs), and a plurality of clutch weights
125. A pocket 130, including cylindrical walls, is formed in the
motor rotor 70 to define the outer drum 115. Forming the outer drum
115 in the motor rotor 70 provides for a more compact arrangement,
while simultaneously reducing the number of components. The clutch
weights 125 are disposed within the drum 115 and are fixedly
attached to the output shaft 100 so that they rotate in unison with
the shaft 100 but are free to move radially. The clutch weights 125
move radially between a disengaged (declutched) position and an
engaged (clutched) position within the pocket 130, with the biasing
member 120 biasing the clutch weights 125 toward the disengaged
position.
[0031] The biasing member 120 is sized to produce a biasing force
that is substantially equal to the centrifugal force applied to the
clutch weights 125 at a predetermined rotational speed. In some
constructions, this predetermined rotational speed is slightly
above the idle speed of the engine 55 such that when the engine 55
idles, the clutch 110 disengages to produce a neutral operating
condition. Of course other constructions may allow clutch
engagement at lower or higher speeds as required by the particular
application. As the engine 55 accelerates, the rotational speed
exceeds the predetermined speed and the centrifugal force applied
to the weights 125 exceeds the force of the biasing members 120.
Once the centrifugal force exceeds the biasing force, the clutch
weights 125 move to the clutched position. In the clutched
position, the clutch weights 125 frictionally engage the drum 115,
or pocket 130, such that the output shaft 100 and the drum 115
(i.e., the rotor 70) rotate in unison.
[0032] During electric motor operation, the motor rotor 70, and the
pocket 130 rotate around the clutch weights 125. However, because
the output shaft 100 does not rotate, no forces are applied to the
clutch weights 125. As such, the clutch weights 125 cannot engage
the cylindrical surface of the pocket 130 and instead remain in the
disengaged or declutched position. Thus, the electric motor 60 does
not transfer torque to the internal combustion engine 55 when the
motor rotor 70 is rotating and the output shaft 100 is stopped or
is rotating too slowly to overcome the biasing force produced by
the biasing member 120. The centrifugal clutch 110 allows the
engine 55 to rotate both the propeller 35 and the motor rotor 70
when the engine 55 is powering the vessel 10 and inhibits rotation
of the engine 55 when the motor 60 is providing power to the
propeller 35.
[0033] FIGS. 4, 7, and 7a illustrate another possible clutch
mechanism 105 that is suited for use with the present engine 15.
The clutch mechanism 105, in the form of a one-way bearing 135
(shown in detail in FIG. 4), is illustrated in FIGS. 7 and 7a in
two possible operating positions. The one-way bearing 135 includes
an outer race 140, an inner cage 145, and a plurality of rolling
members 150. As illustrated in FIG. 7, the outer race 140 engages
the output shaft 100, while the rolling members 150 engage a stub
shaft 155 that is coupled to the motor rotor 70. During operating
conditions in which the stub shaft 155 rotates at a higher speed
than the output shaft 100, the rolling members 150 move into a free
rolling position. In the free rolling position, the rolling members
150 allow relative movement between the stub shaft 155 and the
output shaft 100. If, on the other hand, the output shaft 100
rotates at a higher speed than the stub shaft 155, the rolling
members 150 move into a locked position. With the rolling members
150 in the locked position, the stub shaft 155 and the output shaft
100 rotate in unison. Thus, the bearing 135 allows torque transfer
from the engine 55 to the motor rotor 60 when the output shaft 100
rotates faster than the motor rotor 60. However, the bearing 135
inhibits torque transfer from the motor rotor 70 to the engine 55
when the motor rotor 70 is rotating at a higher speed than the
output shaft 100.
[0034] It should be noted that FIG. 7 illustrates a construction in
which the outer race 140 of the one-way bearing 135 engages the
output shaft 100 and the stub shaft 155 engages the rolling members
150. One of ordinary skill will realize that this arrangement could
be reversed such that the rolling members 150 engage the output
shaft 100 and the outer race 140 engages the stub shaft 155.
[0035] FIG. 7a illustrates another construction in which the stub
shaft 155 is eliminated. In this construction, the outer race 140
of the one-way bearing 135 engages a bearing pocket 160 formed in
the motor rotor 70 and the engine output shaft 100 engages the
rolling members 150 within the bearing 135. This construction has
the advantage of reducing the quantity of components needed and
further reduces the space occupied by the engine 55 and motor
60.
[0036] While bearings 135 of the type described are available from
many sources, one such one-way bearing 135 suited for use with the
present engine 15 is sold by The Timken Company, located in Canton
Ohio, as Timken Torrington Drawn Cup Roller Clutch bearings.
[0037] As illustrated in FIG. 3, the drive shaft 45 extends the
full length of the lower unit 30 and engages the rotor 70. Of
course, other constructions may include two or more shafts that are
directly coupled to one another or indirectly connected (e.g., via
a belt, a chain, a gear, a transmission, and the like). When two or
more shafts are employed, a motor shaft (not shown) engages the
rotor 70 such that rotation of the rotor 70 produces a
corresponding rotation of the motor shaft and the drive shaft 45,
which is coupled to the motor shaft. Connection of the motor shaft
to the rotor 70 may be achieved using many common connections,
including but not limited to, a spline connection or a keyed
connection. Splined and keyed connections provide excellent
rotational coupling, while still allowing for some relative axial
movement between the motor shaft and the rotor 70. Thus, exact
axial positioning of the rotor 70 relative to the motor shaft or
propeller 35 is not necessary.
[0038] While a direct drive system has been described (i.e., the
drive shaft 45 rotates at the same speed as the engine 55 or motor
60), certain applications may employ a transmission disposed
between the internal combustion engine 55 and/or the motor 60 and
the drive shaft 45. The transmission may simply allow the engine 55
or motor 60 to be offset relative to the drive shaft 45 without
changing the rotational speed of the drive shaft 45 or may include
a speed-reducer or a speed-increaser. For example, it may be
desirable to rotate the propeller 35 at a speed that is
substantially faster or substantially slower than the optimal
engine or motor speed. In these applications, a speed-increaser or
a speed-reducer could be positioned between the engine 55 and/or
motor 60 and the propeller 35 to achieve the desired results.
[0039] The use of the clutch mechanism 105 as described allows the
user to switch between engine operation and motor operation without
disturbing any mechanical connections. Thus, the user is not
required to make any mechanical adjustments such as shifting
between gears, engaging the motor 60 with a drive gear, or
disengaging the engine output shaft 100 and the drive shaft 45.
Rather, the user moves an electrical switch 170 (shown in FIGS. 8
and 9) to transition between the engine 55 and the motor 60. The
motor rotor 70, the engine output shaft 100, and the drive shaft 45
remain coupled during all operating modes.
[0040] Both the engine 55 and the motor 60 include separate speed
input systems that allow the user to control the speed of the
vessel 10 using a common interface. To control the speed of the
vessel 10 when operating under engine power, the user adjusts the
throttle position as is well known in the engine art. The outboard
engine 15 includes a tiller arm 175 (shown in FIGS. 1 and 2) that
has a rotatable handle 180 positioned at one end. The rotatable
handle 180 is coupled to a throttle cable such that rotation of the
handle 180 changes the throttle position and varies the speed of
the engine 55. In other constructions, rotation of the handle 180
produces axial movement of a throttle cable. The throttle cable is
threaded through the engine 55 and housing 95 to the carburetor
throttle control such that the motion of the throttle cable
directly adjusts the throttle position. Typically, the rotatable
handle 180 is biased to a low speed or idle position, thereby
requiring the operator to rotate and hold the handle 180 in a
particular position to maintain the speed of the engine 55 above an
idle speed.
[0041] When operating under motor power, the user controls the
speed of the electric motor 60 and not the engine 55. Rather than
provide a separate interface, the present invention provides a
sensor 185 coupled to the rotatable handle 180 of the tiller arm
175. The sensor 185 may be integrated with the throttle control
such that rotation of the handle 180 not only adjusts the throttle
position but also adjusts the sensor 185. For example, a rotary
potentiometer could be positioned such that the movement of the
throttle cable produces a corresponding movement of the
potentiometer. Rotation of the handle 180 would vary the resistance
of the potentiometer (e.g., between 0 and 500 Ohms). The variable
resistance is sensed by the controller 75 and is used as a speed
set point, or is used directly to vary the current provided to the
motor 60. For example, a zero Ohm resistance may be representative
of a maximum speed. Thus, when the potentiometer is rotated to the
zero Ohm position, the controller 75 drives the motor 60 to its
highest rotational speed. Similarly, 500 Ohms may be representative
of zero speed. Thus, when the controller 75 senses 500 Ohms (or
more) of resistance from the potentiometer, the speed of the motor
60 is reduced to a minimum value (zero RPM). In this manner,
rotation of the rotatable handle 180 produces a speed control
signal that the motor controller 75 can use to control the speed of
the motor 60 when the motor 60 is powering the vessel 10.
[0042] One of ordinary skill will realize that other devices could
be used in place of the potentiometer. For example, linear or
rotary variable differential transformers are also well suited to
the task of indicating a desired speed. As such, the present
invention should not be limited to rotary potentiometers or
potentiometers for that matter.
[0043] One possible control system suited to powering and
controlling the electric motor 60 is illustrated in FIG. 8. The
control system includes the switch 170, a relay or contactor 190,
the sensor 185, and an electrochemical energy source in the form of
a battery 195. The switch 170 is generally a double pole switch
movable between a "gas" position and an "electric" position. A
first circuit 200 includes the switch 170, a pair of wires, and a
portion of the engine ignition system. The circuit 200 is
controlled by the switch 170 extends from the engine 55 and, when
closed, grounds the ignition system of the engine 55 to inhibit
engine operation. A second circuit 205 also includes the switch
170, the contactor 190, and the battery 195. The second circuit 205
is controlled by the switch 170 and powers the relay 190 that opens
and closes a contact between the battery 195 and the motor 60. With
the switch 170 in the position illustrated in FIG. 8, the ignition
system is not grounded and is able to provide power to the engine's
spark plug. In addition, the relay circuit is open such that the
power circuit, controlled by the relay 190, remains open and
battery power cannot travel to the motor 60. Thus, the illustrated
configuration would allow engine operation and inhibit motor
operation.
[0044] When the switch 170 is moved to the electric position, both
the relay circuit 205 and the engine ignition system circuit 200
close. With the switch 170 in the closed position, the engine
ignition system is grounded and cannot deliver power to the spark
plugs. Thus, the engine 55 will not operate. In addition, the
closed relay circuit 205 energizes the relay 190 to close the
contact between the battery 195 and the motor 60. Thus, power is
free to travel from the battery 195 to the motor 60 and the motor
60 is able to propel the vessel 10. The sensor 185, (i.e., the
potentiometer) is positioned in the circuit between the motor 60
and the battery 195 to allow the potentiometer to control the power
flow to the motor 60 and to vary the speed of the motor 60. As
discussed, the potentiometer is connected to the rotatable handle
180 of the tiller arm 175 so that a user may rotate the handle 180
to vary the resistance of the circuit and the speed of the motor
60.
[0045] In another construction illustrated in FIG. 10, the sensor
185 includes a rotary switch rather than a potentiometer. Rotation
of the rotatable handle 180 of the tiller arm 175 opens or closes
the rotary switch. When the rotary switch is closed, the motor 60
rotates at a fixed speed and when the switch is open, the motor 60
does not rotate. Thus, the user is able to control the speed of the
vessel 10 when propelled by the motor 60 by rotating the same
handle 180 that is rotated when powered by the internal combustion
engine 55.
[0046] FIG. 9 illustrates another control system suited for use
with the present invention. The control system includes the switch
170, the sensor 185, the motor controller 75, and the
electrochemical energy source in the form of the battery 195. Many
different motor controllers 75 can be used to control the motor 60.
In addition, because many different types of motors 60 can be used
(e.g., brush-type DC motors, brushless DC motors, and the like),
different types of controllers 75 may be employed. For example, a
set of switches and contactors could be used if the motor 60 is a
brush-type DC motor. If the motor 60 is a brushless DC motor, a
MOSFET-based brushless DC motor control would be well-suited to
controlling the motor 60.
[0047] The switch 170 is generally a double pole switch that
controls two separate circuits. A first, or engine ignition circuit
210, is open when the switch 170 is in the "gas" position and is
closed when the switch 170 is moved to the "electric" position. The
ignition circuit 210 includes the switch 170, a pair of wires, and
a portion of the engine ignition system. When the engine ignition
circuit 210 is closed, the ignition system of the engine 55 is
grounded and no electrical power can be delivered to the spark
plug(s) of the engine 55. Thus, engine operation is inhibited. A
second circuit 215 includes the switch 170, and a portion of the
controller 75. The second circuit 215 sends a control signal to the
motor controller 75. When the switch 170 is in the "gas" position,
a signal is sent to the motor controller 75 that allows the motor
controller 75 to function as a power conditioner or regulator such
that electricity generated by the engine driven motor 60 can be
used to charge the battery 195. When the switch 170 is in the
"electric" position, a signal is sent to the controller 75 that
indicates that the controller 75 is controlling the motor 60.
[0048] In other constructions, the second circuit 205 controls a
relay as was described with regard to FIG. 8. In these
constructions, the motor 60 does not charge the battery 195 when
operating under engine power. In still other constructions, the
second circuit 205 is eliminated and the controller 75
automatically determines if it should be regulating power for
delivery to the battery 195 or delivering power to the motor 60 to
propel the vessel 10.
[0049] When operating under motor power, the controller 75 receives
a flow of DC current from the battery 195. The controller 75 in
turn delivers power to the electric motor 60 via two of three power
connections between the controller 75 and the motor 60. Each of the
power connections provides power to a distinct winding within the
stator 65. The power provided by the controller 75 is provided to
the particular windings in a particular order, at a particular
rate, and with a particular polarity to produce a rotating magnet
field within the stator 65. The permanent magnets 85 of the rotor
70 react to the rotating magnetic field by rotating. Thus, by
controlling the rate at which the rotating magnetic field rotates,
the controller 75 is able to control the rotary speed of the motor
60.
[0050] One or more Hall devices or Hall sensors 220 are positioned
adjacent the rotor 70 to sense the actual rotary position of the
rotor 70. The Hall sensors 220 send signals to the controller 75
indicating the actual position of the rotor 70 to allow the
controller 75 to refine the control of the motor 60 and accurately
maintain the desired rotor speed.
[0051] As discussed, the motor controller 75 can also function as a
voltage regulator to charge the battery 195 when the internal
combustion engine 55 is operating and the motor 60 is idle. When
operating under engine 55 power, the internal combustion engine
rotates the rotor 70 without current being provided to the stator
windings. The permanent magnets 85 on the rotor 70 induce an
electrical current in the windings that flows to the controller 75.
The controller 75 conditions the power such that it can be
delivered to the battery 195 to charge the battery 195.
[0052] In use, either the internal combustion engine 55 or the
electric motor 60 can power the vessel 10. In one mode, a user
employs the internal combustion engine 55 to move the vessel 10
toward a desired location. To use the internal combustion engine
55, the switch 170 is positioned in the fuel position and the
engine 55 is started. Once started, the internal combustion engine
55 provides power to the propeller 35 and rotates the motor rotor
70 to charge the battery 195. As the user approaches the desired
location, the internal combustion engine 55 can be shut off and the
switch 170 can be moved to the electric position. In the electric
position, the switch 170 grounds the engine's ignition to inhibit
the combustion process. In addition, the controller 75 provides
power to the electric motor 60, thereby allowing the motor 60 to
propel the vessel 10. The clutch mechanism 105 inhibits rotation of
the engine 55 as the electric motor 60 moves the vessel 10 around
the desired location.
[0053] In the application just described, the electric motor 60
would generally be smaller (output less power) than the internal
combustion engine 55. For example, a twenty horsepower internal
combustion engine may be used with a five horsepower motor. In
other applications, equal power internal combustion engines and
electric motors are used. In still other applications, large
electric motors are used with relatively small internal combustion
engines.
[0054] The present invention can be manufactured as a single unit
or as components that can be applied to pre-existing outboard
motors. When manufactured as components, the electric motor 60 and
controller 75 are generally provided for attachment to a
pre-existing internal combustion engine, such as illustrated engine
55. The engine 55 is decoupled from the drive shaft 45 and removed.
The electric motor 60 is placed in the position previously occupied
by the engine 55 and the motor 60 is coupled to the drive shaft 45.
The support members 103 are positioned as necessary to support the
engine 55 above the motor 60. The engine 55 is repositioned above
the motor 60 and the engine output shaft 100 is coupled, via the
clutch mechanism 105, to the motor rotor 70. In this way, an
internal combustion engine is converted to a hybrid
combustion-electric propulsion system.
[0055] Although the invention has been described in detail with
reference to certain preferred embodiments, variations and
modifications exist within the scope and spirit of the invention as
described and defined in the following claims.
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