NO20210337A1

NO20210337A1 - Hybrid outboard engine

Info

Publication number: NO20210337A1
Application number: NO20210337A
Authority: NO
Inventors: Karl Oskar Fridh
Original assignee: Link Norge As
Priority date: 2021-03-17
Filing date: 2021-03-17
Publication date: 2022-09-19
Also published as: NO346595B1

Description

The present invention relates to a hybrid outboard engine with both an IC-engine and an electric motor.

Electric operation of boats has many advantages as it can be totally quiet, environmentally friendly, and odourless. Clearly, an electric motor will require a battery pack onboard the vessel to be operated. The electric power circuits and control systems can be on board the vessel or may be integrated in the outboard.

Electric operation is particularly useful when sightseeing in vulnerable areas, when studying wildlife and during fishing.

Hybrid operation of outboard engines with electric motors are known from various publications. All these solutions however are related to solutions with a vertical driveshaft and a gearbox in the lower unit. These solutions are not suited for operation of outboards with a gearbox above the waterline and where the drive between the propeller and the gearbox includes a belt.

In the following description is “horizontal”, “vertical”, “right”, “left”, “upper” and “lower” used to simplify the explanation of the invention. In this context do these expressions also indicate an approximate direction or reference during normal use of the outboard engine. “Left” and “right” only refers to the drawing. Similarly, is “reverse” used to indicate an opposite direction. “Reverse” can however indicate a direction for forward motion, and in a twin installation of outboard engines may the propellers of the two outboards run in opposite direction, i.e. one engine is “permanently in reverse”.

Accordingly, the present invention concerns a hybrid outboard engine with an IC-engine comprising a gearbox, and a gearbox output shaft with a propeller belt upper pulley, a propeller shaft with a propeller belt lower pulley, attached to a propeller and a propeller belt extending between the propeller belt upper pulley and the propeller belt lower pulley. An output gear of the gearbox is fixed to the gearbox output shaft. An electric motor with an electric motor shaft in driving connection with the gearbox output shaft.

The gearbox output shaft may extend through the output gear of the gearbox. The propeller belt upper pulley may then be located at a first end of the gearbox output shaft and the electric motor may be in driving connection with a second end of the gearbox output shaft.

The second end of the gearbox output shaft may be in driving connection with the electric motor through a mechanical torque transferring joint.

The electric motor may be in line with the gearbox output shaft.

The second end of the gearbox output shaft may be in driving connection with the electric motor through a motor drivebelt between a gearbox pulley on the gearbox output shaft and a motor pulley on the electric motor shaft.

The hybrid outboard engine may further include a clutch, selectively coupling the electric motor shaft and the gearbox output shaft.

The clutch may be an electro-hydraulic clutch.

The clutch may be a multidisc clutch.

The propeller shaft and the electric motor shaft are parallel.

A crankshaft of the IC-engine may be parallel to the electric motor shaft.

The hybrid outboard engine may further include a driving upper belt between a crank shaft pulley and input shaft pulley of the gearbox.

The gearbox output shaft may extend through an opening in a gearbox lid covering the output gear.

Short description of the drawings:

Fig. 1 is a side view of a first embodiment of a hybrid outboard engine of the invention;

Fig. 2 is a rear view of the first embodiment of the hybrid outboard engine as seen in fig.1;

Fig. 3 is a side view of the first embodiment of the invention shown in a crosssection of an outboard motor;

Fig. 4 is rear view of the configuration of the hybrid outboard engine as shown in fig. 3;

Fig. 5 is a perspective view of the components of a gearbox used in connection with the invention;

Fig. 6 shows the gearbox as shown in fig 5, installed in an outboard motor with a gearbox cover removed;

Fig. 7 is a rear view of an alternative embodiment of the invention where the electric motor is located in an elevated position behind the IC-engine; and Fig. 8 is a side view of the alternative embodiment shown in fig 7.

Detailed description of embodiments of the invention with reference to the drawings:

Fig. 1 is a representation of a configuration of a hybrid outboard engine of the invention from the side. The outboard engine includes a powerhead or IC-engine 9 (internal combustion engine, typically a piston engine) with a horizontal crankshaft. An engine pulley or crankshaft pulley 17 for an upper belt 8 is fixed to the crankshaft. The IC-engine 9 is shown as a “car style” inline turbo diesel engine. The outboard engine includes an input shaft 7 with an input shaft pulley 35 of a gearbox driven by the upper belt 8. An output shaft 5 from the gearbox includes a driven helical gear and a propeller belt upper pulley 4. The propeller belt upper pulley 4 drives a propeller belt 3 and a propeller belt lower pulley 2 on a propeller shaft with a propeller 1. In a preferred embodiment is the engine a diesel engine, but the application is also applicable for solutions with petrol engines. The propeller shaft is in the context of this disclosure the shaft where the propeller is attached, and the axis of rotation of the propeller shaft and of the propeller is the same.

An electric motor 6 with a horizontal shaft drives the propeller belt upper pulley 4 through the output shaft 5 from the gearbox. A mechanical torque transferring joint 36 transfers power and torque between the electric motor 6 and the output shaft 5. The output shaft 5 is longer on an outboard with the electric motor compared to an outboard without electric drive. A multiplate electro-hydraulic clutch 10 may be used to disconnect the output shaft from the electric motor, typically to reduce the inertia of the system. The multiplate electro-hydraulic electric motor clutch 10 allows the electric motor 6 to drive the output shaft 5 for electric operation of the outboard engine or to be released from the output shaft 5 to allow IC-engine operation of the outboard without rotating the electric motor 6. Clearly also the IC-engine can drive the electric motor for charging purposes. The electric motor can also be operated along with the IC motor for extra power.

The multiplate electro-hydraulic clutch 10 may be omitted from the design when it is found unnecessary to enable disconnection of the output shaft from the electric motor.

The electric motor 6 is thus located below the IC-engine and above the propeller shaft and above a typical waterline. The electric motor can be retrofitted to already existing outboard engines of the type described in this disclosure and that are sold under the trade name “OXE”. The Electric motor can be located in a separate housing fixed to the gearbox and can substitute the gearbox cover. A hybrid conversion kit typically includes a new, longer gearbox output shaft 5 with splines to accommodate the propeller belt upper pulley 4, the helical output gear 23 and an electric motor coupling. Furthermore, the kit typically includes a new gearbox cover with an opening and a seal for the gearbox output shaft 5 and a bracket securing the electric motor to the outboard engine.

In alternative embodiments may the upper belt 8 be substituted with another transmission such as a chain or a number of gears, even though such a solution is considered less favourable.

Fig. 2 is a representation of the configuration of the hybrid outboard engine as seen in fig.1 from the back/stern. The outboard engine includes the IC-engine 9 with a horizontal crankshaft seen in a lengthwise direction. The upper belt 8 is inclined in relation to a vertical axis of the outboard engine as the input shaft 7 to the gearbox is off centre. The output shaft from the gearbox with the propeller belt upper pulley 4 and the electric motor 6 is located at the centre of the outboard engine along with the propeller belt 3 and the propeller 1.

Fig. 3 is a representation of the configuration of the hybrid outboard engine as shown in fig.1. The outboard engine includes a mounting bracket 12 for mounting the outboard engine to the transom of a boat. The propeller belt lower pulley is located in a slim lower unit 11 supporting the propeller shaft with the propeller shaft pulley. The slim lower unit 11 includes the fin and is complete without any gears. An anti-ventilation plate 16 is located above the propeller. A mid-section 14 secures the lower unit 11 to the powerhead and the gearbox. The mid-section 14 can be made in different lengths as required. The upper belt driving the gearbox 13 is located in an upper belt housing 15. A motor shaft 37 of the electric motor 6 is connected to the longer gearbox output shaft 5 with splines through a mechanical coupling 38. The mechanical coupling 38 may be a sleeve with internal spines in mating contact with splines on the gearbox output shaft 5 and the motor shaft 37 or any other suitable coupling transferring power and torque.

Fig. 4 is a representation of the configuration of the hybrid outboard engine as shown in fig.3 from the back/stern. The inclined upper belt housing 15 hiding the crank shaft pulley 17 drives the gearbox, and the centred electric motor 6 extends from a rear of the gearbox and is located above the mid-section 14. The antiventilation plate 16 is located above the propeller. The gearbox output shaft 5 extends through an opening in a gearbox lid 39 covering the output gear 23 and the other gears of the gearbox.

Fig. 5 is a perspective view of the gearbox. An electrohydraulic input clutch 27 selectively couples or releases a helical secondary input gear 24 from a helical primary input gear 21 and an input shaft 26. Similarly does an electrohydraulic reverse clutch 22 selectively couple or release a helical secondary reverse gear 25 from a helical reverse input gear 20. The helical primary input gear 21 is in mesh with the helical reverse input gear 20. The helical secondary input gear 24 and the helical secondary reverse gear 25 are in constant mesh with a helical output gear 23 on the output shaft 5. The electric motor is a direct drive motor driving the output shaft 5 from an input shaft 28 along the indicated line.

The electrohydraulic clutches 22, 27 selectively control drive between forward, reverse or neutral.

Fig. 6 shows the gearbox as shown in fig 5 from the rear. The electric motor drives the input shaft 28 from the electric motor through a clutch. The helical output gear 23 is fixed to the input shaft 28 from the electric motor also forming the output shaft from the gearbox.

The electrohydraulic input clutch 27, the helical secondary input gear 24 and the helical primary input gear 21 are located on the same shaft. Similarly, are the electrohydraulic reverse clutch 22, the helical secondary reverse gear 25 and the helical reverse input gear 20 located on the same shaft. The gearbox is located above a waterline of the outboard engine. The gearbox is located behind a gearbox cover and a sealing surface 29 forms a seal between the gearbox and the gearbox cover. The gearbox cover is attached to the gearbox through bolts threaded into a number of threaded bolt holes 31. Locating pegs in the gearbox cover extend into peg holes 30 in the gearbox. The electric motor may be integrated in the gearbox cover. Alternatively, will the shaft to the electric motor extend through the gearbox cover as shown in fig.3

Figs. 7 and 8 are a rear view and a side view respectively of an alternative embodiment of the invention where the electric motor 6 is located in an elevated position behind the IC-engine. The electric motor 6 drives a motor pulley 33 fixed to the motor shaft and a gearbox pulley 34 is fixed to the gearbox output shaft 5. A motor drivebelt 32 provides a transmission between the motor shaft and the gearbox output shaft 5. This arrangement moves the electric motor 6 further away from a sea level, provides greater flexibility on the location of the motor and an extra possibility of controlling the gear ratio between the electric motor 6 and the gearbox output shaft 5, enabling a wider selection of motors to be used.

The shaft of the electric motor, the crankshaft of the IC-engine, the propeller shaft and the shafts in the gearbox are parallel.

Modes of operation (clutches not mentioned are released):

Only IC-engine running, no charging, forward motion:

Input clutch 27 is locking helical secondary input gear 24 to helical primary input gear 21.

Only IC-engine running, no charging, reverse motion:

Reverse clutch 22 is locking helical secondary reverse gear 25 to helical reverse input gear 20.

Only electric motor running, forward motion:

Electric motor clutch 10 locked, electric motor 6 rotates in a first direction.

Only electric motor running, reverse motion:

Electric motor clutch 10 locked, electric motor 6 rotates in a second direction.

Combined operation, forward motion:

IC-engine running, input clutch 27 is locking helical secondary input gear 24 to helical primary input gear 21, electric motor clutch 10 is locked, electric motor 6 drives.

Charging while in forward motion:

IC-engine running, input clutch 27 is locking helical secondary input gear 24 to helical primary input gear 21, electric motor clutch 10 is locked, electric motor 6 is driven for charging.

Claims

1. Hybrid outboard engine with an IC-engine (9) comprising a gearbox, and a gearbox output shaft (5) with a propeller belt upper pulley (4), a propeller shaft with a propeller belt lower pulley (2), attached to a propeller (1) and a propeller belt (3) extending between the propeller belt upper pulley (4) and the propeller belt lower pulley (2);

an output gear (23) of the gearbox fixed to the gearbox output shaft (5); and an electric motor (6) with an electric motor shaft (37) in driving connection with the gearbox output shaft (5).

2. The hybrid outboard engine of claim 1, wherein the gearbox output shaft (5) extends through the output gear (23) of the gearbox, and wherein the propeller belt upper pulley (4) is located at a first end of the gearbox output shaft (5) and the electric motor is in driving connection with a second end of the gearbox output shaft (5).

3. The hybrid outboard engine of claim 2, wherein the second end of the gearbox output shaft (5) is in driving connection with the electric motor (6) through a mechanical torque transferring joint.

4. The hybrid outboard engine of claim 3, wherein the electric motor (6) is in line with the gearbox output shaft (5).

5. The hybrid outboard engine of claim 2, wherein the second end of the gearbox output shaft (5) is in driving connection with the electric motor (6) through a motor drivebelt (32) between a gearbox pulley (34) on the gearbox output shaft (5) and a motor pulley (33) on the electric motor shaft (37).

6. The hybrid outboard engine of claim 1, further including a clutch (10), selectively coupling the electric motor shaft (37) and the gearbox output shaft (5).

7. The hybrid outboard engine of claim 2, wherein the clutch is an electro-hydraulic clutch.

8. The hybrid outboard engine of claim 2 wherein the clutch (10) is a multidisc clutch.

9. The hybrid outboard engine of any of the preceding claims, wherein the propeller shaft (2) and the electric motor shaft (37) are parallel.

10. The hybrid outboard engine of any of claim 9, wherein a crankshaft of the IC-engine is parallel to the electric motor shaft (37).

11. The hybrid outboard engine of any of the preceding claims, further including a driving upper belt (8) between a crank shaft pulley (17) and input shaft pulley (35) of the gearbox.

12.The hybrid outboard engine of claim 1, wherein the gearbox output shaft (5) extends through an opening in a gearbox lid (39) covering the output gear (23).