GB2577108A

GB2577108A - Marine outboard motor with improved protective cover

Info

Publication number: GB2577108A
Application number: GB1814994.8A
Authority: GB
Inventors: Krysik Paul
Original assignee: Cox Powertrain Ltd
Current assignee: Cox Powertrain Ltd
Priority date: 2018-09-14
Filing date: 2018-09-14
Publication date: 2020-03-18
Also published as: GB201814994D0

Abstract

A marine outboard motor (2, Fig 3) comprises an internal combustion engine (30, Fig 3) connected to a propulsion device (8, Fig 3) and a protective cover 100 removably attached to the internal combustion engine. The internal combustion engine comprises at least one air duct configured to route intake air to the internal combustion engine. The protective cover comprises a cover duct 103 that forms part of the at least one air duct. The protective cover may be a timing device cover and may provide a bifurcated Y-shaped air duct with an intake air inlet and at least two inlet air outlets. An engine assembly formed from an internal combustion engine and a protective cover comprising a cover duct forming an air duct is also disclosed.

Description

(71) Applicant(s):

Cox Powertrain Limited

The Cecil Pashley Building, 8 Cecil Pashley Way, Brighton City Airport, Lancing, BN43 5FF, United Kingdom (72) Inventor(s):

Paul Krysik (74) Agent and/or Address for Service:

Withers & Rogers LLP

More London Riverside, LONDON, SE1 2AU, United Kingdom (51) INT CL:

F02M 35/16 (2006.01)

F02B 81/04(2006.01)

B63H 20/00 (2006.01)

F02M 35/10 (2006.01) (56) Documents Cited:

JP 030690869 B US 5899778 A

US 20020104502 A1 (58) Field of Search:

INT CL B63H, F02B, F02M Other: EPODOC, WPI (54) Title of the Invention: Marine outboard motor with improved protective cover Abstract Title: A marine outboard motor with a protective cover air duct (57) A marine outboard motor (2, Fig 3) comprises an internal combustion engine (30, Fig 3) connected to a propulsion device (8, Fig 3) and a protective cover 100 removably attached to the internal combustion engine. The internal combustion engine comprises at least one air duct configured to route intake air to the internal combustion engine. The protective cover comprises a cover duct 103 that forms part of the at least one air duct. The protective cover may be a timing device cover and may provide a bifurcated Y-shaped air duct with an intake air inlet and at least two inlet air outlets. An engine assembly formed from an internal combustion engine and a protective cover comprising a cover duct forming an air duct is also disclosed.

FIG. 5a

1/10

^v8

HG. 1

2/10

FIA 2d ί 8 W □ &oU

3/10

FIG. 3

4/10

FIG. 4a

5/10

105

FIG. 4b

6/10

FIG. 5a

FIG. 5b

7/10

FIG. 5d

8/10

FIG. 6

9/10

200

FIG. 7a

9Ί Ί 201,201 a

FIG. 7b

10/10

rlU. Ο

MARINE OUTBOARD MOTOR WITH IMPROVED PROTECTIVE COVER

Technical Field

The present invention relates to a marine outboard motor, comprising an improved protective cover. While this application relates to marine outboard motors, the teachings may also be applicable to any other internal combustion engine including protective covers.

Background

At present, the outboard engine market is dominated by petrol engines, which are mainly designed for smaller vessels, i.e. for the leisure market. Petrol engines are generally lighter than their diesel equivalents. However, a range of users, from military operators to super-yacht owners begin to favour diesel outboard motors because of the improved safety of the heavier diesel fuel due to its lower volatility, and fuel compatibility with the mother ship. Furthermore, diesel is a more economical fuel source with a more readily accessible infrastructure.

In view of the above, diesel outboard motors have become the focus of marine research activity, with an aim to transforming the outboard engine market.

In order to fulfil current emissions standards, diesel internal combustion engines nowadays include more sophisticated charge systems. The new engines exhibit better performance, both in terms of power output and exhaust emission. Modern diesel engines use direct cylinder injection to improve performance characteristics. By injecting pressurised fuel directly into the combustion chambers, it is possible to achieve more complete combustion resulting in better engine economy and emission control.

Many of the new diesel engines for outboard motors are turbodiesel engines, i.e. diesel engines equipped with a turbocharger. Turbocharging is commonly known to produce higher power outputs, lower emission levels, and improved efficiency compared to the use of diesel engines without a turbocharger. In a turbocharger, pressurised intake air is introduced into the intake manifold of the internal combustion engine to improve efficiency and power output by forcing extra amounts of air into the combustion chambers. Turbocharged diesel engines typically take up more space than their noncharged equivalents. Particularly in the technical field of marine outboard motors, this is common problem since the available space envelopes are usually significantly smaller than the ones of their automotive equivalents.

In many marine outboard engines, the intake manifold of the internal combustion engine needs to be connected to an air inlet filter, and thus requires a variety of air ducts connecting the two. Such air ducts should be as far removed from the engine block as possible in order to prevent intake air from being heated by the engine, as warmer intake air will result in reduced engine efficiency. On the other hand, arranging air ducts distant from the engine block further increases the size of the outboard motor.

In view of the above, it is an object of the present invention to overcome the problems associated with conventional solutions and provide a new marine outboard motor with reduced packaging space and weight, without affecting the efficiency of the combustion engine.

According to a first aspect of the present invention, there is provided a marine outboard motor comprising an internal combustion engine connected to a propulsion device and comprising at least one air duct configured to route intake air to the internal combustion engine. The marine outboard motor further comprises a protective cover removably attached to the internal combustion engine, wherein the protective cover comprises a cover duct forming at least parts of the at least one air duct.

According to the present invention, at least parts of the air duct are integrated into the protective cover of the marine outboard motor. As such, the overall size and weight of the motor can be reduced as compared to air ducts that run along the engine block separate from the protective cover. The protective cover itself may also act as a thermal shield protecting the intake air from the heat generated by the engine block.

In one embodiment of the present invention, the protective cover is a timing device cover. In other words, the protective cover may be used to cover timing parts of the internal combustion engine, such as timing wheels and their corresponding timing belts / timing chains. The latter may connect parts like the crankshaft and the camshaft in a synchronised manner. The protective cover can be removed from the outboard motor in order to service the timing devices. When removing the protective cover from the engine block, it is advantageously also possible to service the cover duct.

In another embodiment, the internal combustion engine comprises a crankshaft for driving the propulsion device, the crankshaft, in use, being arranged to rotate about a substantially vertical crankshaft axis, wherein the protective cover is arranged to cover a top end of the crankshaft. In other words, the protective cover may be arranged on top of the outboard motor to simplify maintenance works. A corresponding timing wheel may be arranged at the top end of the crankshaft, the timing wheel being covered by the protective cover. The timing wheel may be a timing pulley, timing gear, or any other timing suitable rotatable timing wheel.

In yet another embodiment, the cover duct is a bifurcated air duct. As such, the cover duct may split the flow of intake air into two or more air paths along the length of the protective cover. The cover duct may be substantially Y-shaped. The cover duct may comprise at least one intake air inlet and at least two intake air outlets.

The intake air inlet may be connected to an intake air cooler. The intake air cooler may be arranged on one end of the internal combustion engine, which is opposite to the intake manifold.

In another variation of the present invention, the first intake air outlet is connected to a first intake manifold of the internal combustion engine, the first intake manifold being arranged to supply intake air to a first cylinder head. A second intake air outlet may be connected to a second intake manifold of the internal combustion engine. The second intake manifold being arranged to supply intake air to a second cylinder head. The protective cover may, therefore, be used to supply two separate intake manifolds with a single intake air inlet. As such, the protective cover not only transfers intake air between the air cooler and the intake manifold but also acts as an intake air distribution device.

According to another embodiment, the protective cover comprises a main body having an inner surface facing the internal combustion engine, in use, and an outer surface, opposite to the inner surface, wherein the cover duct is arranged on the outer surface of the main body. In other words, the cover duct is arranged facing away from the engine block, such that the inner surface of the protective cover acts as a thermal shield preventing heat emitted by the engine block from increasing the temperature of the cooled intake air.

In another embodiment, every part of the cover duct is integrally formed with the main body of the protective cover. In this embodiment, the protective cover is a single piece including the cover duct.

In an alternative embodiment, parts of the cover duct are formed integrally with the main body of the protective cover and form a first half-shell of the cover duct. In one example, the first half-shell may be a lower shell. The cover duct may comprise a second half-shell removably attached to the first half-shell. If the first half-shell integrated within the protective cover is a lower shell, then the second half-shell is a removable top half. Constructing the cover duct as a two-piece structure with removable half-shells further simplifies maintenance of the cover duct as will be explained in more detail below. The first half-shell and the second half-shell may comprise a plurality of corresponding mounting holes arranged to receive fastening members.

In another embodiment, the main body of the protective cover comprises a service opening configured to allow access to a top end of the internal combustion engine. According to this embodiment, the crankshaft may be accessed via the service opening without removing the protective cover. It may thus be possible to allow an eye bolt to be screwed into the center of the flywheel boss via the service opening, for the purpose of lifting the engine. The service opening may extend between an outer surface and an inner surface of the protective cover. The service opening may be arranged on the first half-shell, which is integrated into the main body of the protective cover.

The protective cover may comprise a service flap covering the service opening. The service flap may be pivotable between an operating position and the maintenance position. In the operating position, the service flap may be closed, thereby covering the service opening such that intake air is prevented from entering the timing device cavity formed by the inner surface of the protective cover. In other words, when the service flap is in its closed, operating position, intake air will exclusively flow between the inlet and the two outlets. In its open, maintenance position, the service flap is pivoted away from the service opening, such that an operator can gain access to parts of the internal combustion engine below the service opening. The service opening may further be used as an access opening to clean the cover duct during maintenance.

In another embodiment, a main body of the protective cover has an inner surface facing the internal combustion engine, in use, and an outer surface, opposite the inner surface, wherein reinforcement elementsare located on the inner surface and/or the outer surface. In use, the protective cover may extend over a large part of the engine block, requiring sufficient integral stability for the cover. Arranging reinforcement elements on the inner and/or outer surface of the protective cover will facilitate structural integrity even for large protective covers.

In a further embodiment, the protective cover may comprise sound insulating means attached to the inner and/or outer surface of the protective cover. In one example, acoustically damping materials may be applied to the inner and/or outer surface of the protective cover to reduce noise levels of the outboard motor.

The internal combustion engine may comprise an engine block having first and second cylinder banks. In particular, the internal combustion engine may be a V-engine. In other words, the internal combustion engine may comprise a V-shaped engine block having first and second cylinder banks. In an alternative embodiment, the engine may be an in line engine.

In another embodiment, the internal combustion engine is a diesel engine, preferably a turbocharged diesel engine.

According to another aspect of the present invention, there is provided a marine vessel comprising an outboard motor described hereinbefore. Although the present invention has been described in relation to an outboard motor for a marine vessel, it is generally feasible to utilise the protective cover in any kind of internal combustion engine, such as combustion engines for aircraft or helicopter propulsion.

According to yet another aspect, there is provided an engine assembly including an internal combustion engine comprising at least one air duct configured to route intake air to the internal combustion engine. The engine assembly is further comprises a protective cover removably attached to the internal combustion engine, wherein the protective cover comprises a cover duct forming at least parts of the at least one air duct.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim even if not originally claimed in that manner.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:

FIGURE 1 is a schematic side view of a light marine vessel provided with an outboard motor;

FIGURE 2a shows a schematic representation of an outboard motor in its tilted position;

FIGURES 2b to 2d show various trailing positions of the outboard motor and the corresponding orientation of the mooring vessel within a body of water;

FIGURE 3 shows a schematic cross-section of an outboard motor including a vertical crankshaft;

FIGURE 4a shows a perspective back view of an internal combustion engine and protective cover used in an outboard motor according to an embodiment of the present invention;

FIGURE 4b shows a perspective cross-section along the top end of the assembly shown in Figure 4a;

FIGURE 5a shows a perspective top view of the protective cover used in the outboard motor of Figure 4a;

FIGURE 5b shows a top view of the protective cover of Figure 5a;

FIGURE 5c shows a bottom view of the protective cover of Figure 5a;

FIGURE 5d shows a perspective cross-section of the protective cover of Figure 5a;

FIGURE 6 shows a perspective front view of an internal combustion engine and protective cover used in an outboard motor according to another embodiment of the present invention;

FIGURE 7a shows a perspective view of the protective cover used in the assembly of Figure 6;

FIGURE 7b shows a top view of the protective cover shown in Figure 7a; and

FIGURE 8 shows a perspective view of an internal combustion engine and protective cover used in an outboard motor according to another embodiment of the present invention.

Detailed Description

Referring firstly to Figure 1, there is shown a schematic side view of a marine vessel 1 with an outboard motor 2. The marine vessel 1 may be any kind of vessel suitable for use with an outboard motor, such as a tender or a scuba-diving boat. The outboard motor 2 shown in Figure 1 is attached to the stern of the vessel 1. The outboard motor 2 is connected to a fuel tank 3, usually received within the hull of the marine vessel 1. Fuel from the reservoir or tank 3 is provided to the outboard motor 2 via a fuel line 4. Fuel line 4 may be a representation for a collective arrangement of one or more filters, low pressure pumps and separator tanks (for preventing water from entering the outboard motor 2) arranged between the fuel tank 3 and the outboard motor 2.

As will be described in more detail below, the outboard motor 2 is generally divided into three sections, an upper-section 21, a mid-section 22, and a lower-section 23. A propeller 8 is rotatably arranged on a propeller shaft 9 at the lower-section 23, also known as the gearbox, of the outboard motor 2. Of course, in operation, the propeller 8 is at least partly submerged in water and may be operated at varying rotational speeds to propel the marine vessel 1.

Typically, the outboard motor 2 is pivotally connected to the stern of the marine vessel 1 by means of a pivot pin. Pivotal movement about the pivot pin enables the operator to tilt and trim the outboard motor 2 about a horizontal axis in a manner known in the art. Further, as is well known in the art, the outboard motor 2 is also pivotally mounted to the stern of the marine vessel 1 so as to be able to pivot about a generally upright axis, to steer the marine vessel 1.

Tilting is a movement that raises the outboard motor 2 far enough so that the entire outboard motor 2 is able to be raised completely out of the water. Tilting the outboard motor 2 may be performed with the motor 2 turned off or in neutral. However, in some instances, the outboard motor 2 may be configured to allow limited running of the motor 2 in the tilt range so as to enable operation in shallow waters. Outboard engines are therefore predominantly operated with a longitudinal axis of the leg in a substantially vertical direction. As such, a crankshaft of an engine of the outboard motor which is substantially parallel to a longitudinal axis of the leg of the outboard motor will be generally oriented in a vertical orientation during normal operation of the outboard motor, but may also be oriented in a non-vertical direction under certain operating conditions, in particular when operated on a vessel in shallow water. A crankshaft of an outboard motor, which is oriented substantially parallel to a longitudinal axis of the leg of the outboard can also be termed a vertical crankshaft arrangement. A crankshaft of an outboard motor which is oriented substantially perpendicular to a longitudinal axis of the leg of the outboard can also be termed a horizontal crankshaft arrangement.

As mentioned previously, to work properly, the lower-section 23 and propeller 8 of the outboard motor 2 needs to extend into the water. In extremely shallow waters, however, or when launching a vessel off a trailer, the lower-section 23 of the outboard motor 2 could drag on the seabed or boat ramp if in the tilted-down position. Tilting the motor 2 into its tilted-up position, such as the position shown in Figure 2A, prevents such damage to the lower-section 23 and the propeller 8.

By contrast, trimming is the mechanism that moves the motor 2 over a smaller range from a fully-down position to a few degrees upwards, as shown in the three examples of Figures 2B to 2D. Trimming will help to direct the thrust of the propeller 8 in a direction that will provide the best combination of fuel efficiency, acceleration and high speed operation of the corresponding marine vessel 1.

When the vessel 2 is on a plane (i.e. the weight of the vessel 1 is predominantly supported by hydrodynamic lift, rather than hydrostatic lift, a bow-up configuration results in less drag, greater stability and efficiency. This is generally the case when the keel line of the boat or marine vessel 1 is up about three to five degrees, such as shown in Figure 2B for example.

Too much trim-out puts the bow of the vessel 1 too high in the water, such as the position shown in Figure 2C. Performance and economy, in this configuration, are decreased because the hull of the vessel 1 is pushing the water and the result is more air drag. Excessive trimming-up can also cause the propeller to ventilate, resulting in further reduced performance. In even more severe cases, the vessel 1 may hop in the water, which could throw the operator and passengers overboard.

Trimming-in will cause the bow of the vessel 1 to be down, which will help accelerate from a standing start. Too much trim-in, shown in Figure 2D, causes the vessel 1 to plough through the water, decreasing fuel economy and making it hard to increase speed. At high speeds, trimming-in may even result in instability of the vessel 1.

Turning to Figure 3, there is shown a schematic cross-section of an outboard motor 2 including a drive system according to an embodiment of the present invention. The outboard motor 2 comprises a tilt and trim mechanism 7 for performing the aforementioned tilting and trimming operations. In this embodiment, the tilt and trim mechanism 7 includes a hydraulic actuator 71 that can be operated to tilt and trim the outboard motor 2 via an electric control system. Alternatively, it is also feasible to provide a manual tilt and trim mechanism, in which the operator pivots the outboard motor by hand rather than using a hydraulic actuator shown in Figure 3.

As mentioned hereinbefore, the outboard motor 2 is generally divided into three sections. An upper-section 21, also known as the powerhead, includes a combustion engine 30, which will be described in more detail below. Adjacent to and extending below the upper-section 21 of the power head, there is provided a mid-section 22, also known as the exhaust housing. The mid-section 22 or exhaust housing connects the upper-section 21 to the lower-section 23 and houses a drive shaft 41 connected to the crankshaft 31 of the combustion engine 30. At the same time, the mid-section 22 commonly defines an exhaust path transporting exhaust gasses from the outlet of the combustion chambers towards the lower-section 23. The lower-section 23 extends adjacent to and below the mid-section 22. An anti-ventilation plate 51, which prevents surface air from being sucked into the negative pressure side of the propeller 8, separates the mid-section 22 from the lower-section 23.

Referring back to the combustion engine 30 provided in the power head or upper-section 21 of the outboard motor 2, there is shown a schematic representation of one side of a four-stroke V6 diesel engine. It will be understood that any other amount of cylinders may be employed in the V-shaped cylinder banks. The skilled person will also understand that any other arrangement, such as an in-line arrangement could alternatively be utilised. Finally, while Figure 3 illustrates a four-stroke-type engines, the drive system of the present invention could equivalently be constructed as a twostroke-type combustion engine.

The combustion engine 30 shown schematically in Figure 3 includes a variety of combustion chambers/cylinders 33a, 33b, and 33c. Each of the combustion cylinders 33a, 33b, and 33c is provided with a moveable piston 35a, 35b, and 35c. Each of the pistons 35a to 35c is connected at its back end to a crankshaft 31 as is well known in the art. The pistons 35a to 35c separate the crankshaft 31 from the combustion section of gthe cylinders 33a to 33c, that is, from inlet and outlet ports controlled by corresponding inlet valves 37a, 37b, 37c and outlet valves 38a, 38b and 38c.

The crankshaft 31 is connected at its lower end to a drive shaft 41 via a floating connector 53 (e.g. a splined connection), which will facilitate assembly of the drive shaft and the crankshaft. At the lower end of the drive shaft 41, a gear box / transmission is provided that supplies the rotational energy of the drive shaft 41 to the propeller 8 in a horizontal direction. In more detail, the bottom end of the drive shaft 41 may include a bevel gear 43 connected to a pair of bevel gears 85, 86 that are rotationally connected to a horizontal input shaft 83 of the propeller 8.

Figure 3 also schematically shows a disconnect mechanism 45, which may be used to disconnect the drive shaft 41 from the input shaft 83.

At its upper end, the crankshaft 31 is provided with a flywheel 39. Although not shown in detail in Figure 3, the fly wheel includes a pulley connected to the crankshaft. The crankshaft pulley is connected to a drive pulley 63 of a camshaft 61 via a timing belt 81. It will be understood that Figure 3 only shows one cylinder bank. As such, a substantially identical, second camshaft can be provided for the second cylinder bank of the V6 engine, said second camshaft being connected to the fly wheel 39 via a second timing belt.

The camshaft 61 extends parallel to the crankshaft 31, i.e. along a substantially vertical axis in Figure 3. As is generally known, the camshaft 61 includes a variety of cams for actuating the inlet and outlet valves 37a, 37b, 37c, 38a, 38b, 38c, in an accurately timed fashion. The rotational speed ratio between the crankshaft and the camshaft is conventionally set by means of the flywheel, pulleys and their corresponding timing belt. These parts of the internal combustion engine are, therefore, commonly referred to as timing devices.

In order to protect the timing devices from environmental influences, such as water and dust, and to prevent risk of harm to the operator, a protective cover 100 may be arranged on top of the engine block 30. Although in Figure 3, the protective cover 100 is illustrated covering the top end of the engine block 30, it will be appreciated that the protective cover could also be arranged to span any other part of the engine block 30. Surrounding the engine block 30 and the protective cover 100 is an outer cowling 90. In order to access the protective cover, and therefore the engine block 30, parts of the cowling 90 have to be removed/opened during maintenance operations.

Figures 4a and 4b show more detailed views of one example of an internal combustion engine 30 with a removable protective cover 100, spanning the top part of the engine block and protecting the timing devices. At least one air duct 32 runs from one side of the internal combustion engine 30 to the other and is configured to route intake air from an air intake (not shown) to cylinder heads of the internal combustion engine.

The protective cover 100 is removably attached to the internal combustion engine 30 to allow easy access for maintenance purposes. The protective cover 100 comprises a main body 101 and at least one cover duct 103 forming at least parts of the air duct 32.

As can be derived from Figures 4a and 4b, the cover duct 103 is bifurcated and substantially Y-shaped. The cover duct 103 has one inlet 105. The inlet 105, in this embodiment, is connected to an intake air cooler 91. Cool intake air entering the cover duct 103 via inlet 105 is transferred to air outlets 107a, 107b. The air outlets 107a, 107b are arranged at an opposite end to the air inlet 105. Each of the air outlets 107a, 107b is connected to a respective intake manifold 93a, 93b. As such, the cover duct 103 provides cooled intake air from the intake air cooler 91 to both intake manifolds 93a, 93b across the top end of the engine.

As is derivable from Figure 4b, the protective cover 100 covers a crankshaft opening 301 and two camshaft openings 303a, 303b. Similar to the illustration of Figure 3, a crankshaft and two camshafts will be received in their respective openings 301, 303a, and 303b. On the top end of each of the shafts, timing wheels, such as timing gears and timing pulleys, and corresponding timing belts will be arranged and protected by the protective cover 100.

Figures 5a to 5d show different views of the protective cover 100 shown in Figures 4a and 4b. The protective cover 100 comprises a main body 101. The main body 101 can be removably attached to the engine block via mounting protrusions 109a and 109b and 109c. The mounting protrusions 109a, 109b, 109c include respective mounting holes for corresponding fastening members. The main body has an outer surface 111, shown in Figures 5a and 5b and an opposite, inner surface 113, shown in Figure 5c. The inner and outer surfaces 111, 113 of the main body 101 include outer reinforcement elements 115 and inner reinforcement elements 117 respectively.

A first part 101a of the main body is substantially triangular and configured to cover the timing devices and camshafts of the internal combustion engine 30. A second, substantially circular part 101b of the main body 101 is configured to cover the flywheel of the crankshaft. The first part 101a is a solid part, that is, there are no openings extending between the outer surface 111 and the inner surface 113 of the first part 101a. The second, substantially circular part 101b has a plurality of openings 119 extending between the outer surface 111 and the inner surface 113 of the main body 101. These opening 119 facilitate the removal of excess heat from the engine block by means of the fly wheel, which can push hot air out via said openings 119.

It will be appreciated from Figures 5a to 5d that at least parts of the cover duct 103 form an integral structure together with the main body 101 of the protective cover 100. In detail, the cover duct 103 shown in Figures 5a to 5d is made up of two half-shells. A lower half-shell 121 is formed as an integral structure together with the main body 101. A second, upper half-shell 123 is constructed as a separate, removable part of the protective cover 100. The upper half-shell 123 is removably attached to the lower halfshell 121 via a plurality of mounting holes 125 arranged along an outer edge of both, the upper and lower half-shells 121, 123. The lower half-shell 121, which is formed as an integral part of the main body 101, forms part of the outer surface 111, as can be seen in Figure 5d. In other words, the cover duct 103 is arranged on the outer surface 111 of the protective cover 100, such that the intake air is disconnected from the heat of the engine block rising towards the inner surface 113 of the protective cover 100.

Figures 5c and 5d show a service opening 127, which extends through the main body 101 of the protective cover 100 between the inner and outer surface 111, 113. The service opening 127 extends into the lower half-shell 121 of the cover duct 103 at the bifurcation of the cover duct 103. The service opening 127 enables the operator to gain quick access to the timing devices if the upper half-shell 123 is removed, without the need for removal of the entire protective cover 100. In order to close the service opening 127 during normal use of the cover duct 103, a service flap may be provided at a lower end of the service opening 127. The service flap (not shown) may pivot around a mounting hole 129 (Figure 5c), which is arranged adjacent to the service opening 127.

In operation, the cover duct 103 will split the air passed through the inlet 105 into two separate paths ending at outlets 107a, 107b respectively. The bifurcated configuration of the cover duct 103, therefore, assists with distribution of the intake air between the two intake manifolds and is particularly compact due to the integrated nature of the lower half-shell 121 with the main body 101 of the protective cover 100.

Another variant of a protective cover 200 is shown in Figure 6 together with an internal combustion engine 230. Again, the protective cover comprises a cover duct 203 transferring intake air between an air cooler 291 and intake manifolds 293 an forming parts of the internal combustion engine air duct.

A perspective view and a top view of the protective cover 200 are shown in Figures 7a and 7b. The general shape of the protective cover 200 is substantially the same as protective cover 100. In particular, the cover duct 203 is also a bifurcated, particularly Y-shaped, air duct with one inlet and two outlets. However, in contrast to the protective cover 100 shown in Figures 5a to 5d, the entire protective cover 200 is constructed as a single piece. In other words, the cover duct 203 is exclusively formed as an integrated structure together with the main body 201.

Again, the protective cover 200 comprises a solid first body part 201a and a second body part 201b including a plurality of openings extending between an outer surface 211 and an inner surface (not shown).

Another, third variant of a protective cover 300 is shown in Figure 8 together with an internal combustion engine 330. The protective cover 300 includes a cover duct 303. The entire cover duct 303 is integrally formed with a main body 305 of the protective cover. The cover duct 303 has is, again, bifurcated and is substantially Y-shaped.

The protective cover 300 comprises a service opening 327 and an opening for weight reduction 329. The service opening 327 is accessible from an outer surface 311 of the protective cover 300. The service opening 327 and opening 29 extend through the protective cover 300 between its outer surface 311 and its inner surface (not shown). The service opening 327 is arranged at an intake air inlet end of the protective cover 300. The service opening 327 is sized and shaped to allow an eye bolt (not shown) to be screwed into the center of a flywheel boss via the service opening 327, for the purpose of lifting the engine.

In the example of Figure 8, the service opening 327 is circular. The cover duct 303 of the protective cover 300 extends around the service opening 327 in a toroidal shape. The opening 329 is arranged between bifurcated outflow portions 340 and 342 of the cover duct 303 and has a substantially triangular shape.

Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. A marine outboard motor comprising:

an internal combustion engine connected to a propulsion device and comprising at least one air duct configured to route intake air to the internal combustion engine; and a protective cover removably attached to the internal combustion engine, wherein the protective cover comprises a cover duct forming at least parts of the at least one air duct.

2. The marine outboard motor of claim 1, wherein the protective cover is a timing device cover.

3. The marine outboard motor of claim 2, wherein the internal combustion engine comprises a crankshaft for driving the propulsion device, the crankshaft, in use, being arranged to rotate about a substantially vertical crankshaft axis, and wherein the protective cover is arranged to cover a top end of the crankshaft.

4. The marine outboard motor of claim 3, wherein a timing wheel is arranged at the top end of the crankshaft, the timing wheel being covered by the protective cover.

5. The marine outboard motor of any of claims 1 to 4, wherein the cover duct is a bifurcated air duct.

6. The marine outboard motor of claim 5, wherein the cover duct is substantially Yshaped.

7. The marine outboard motor of claim 5 or 6, wherein the cover duct has an intake air inlet and at least two intake air outlets.

8. The marine outboard motor of claim 7, wherein the intake air inlet of the cover duct is connected to an intake air cooler.

9. The marine outboard motor of claim 7 or 8, wherein a first intake air outlet is connected to a first intake manifold of the internal combustion engine, the first intake manifold being arranged to supply intake air to a first cylinder head.

10. The marine outboard motor of any of claims 7 to 9, wherein a second intake air outlet is connected to a second intake manifold of the internal combustion engine, the second intake manifold being arranged to supply intake air to a second cylinder head.

11. The marine outboard motor of any of claims 1 to 10, wherein the protective cover has a main body, the main body comprising an inner surface facing the internal combustion engine, in use, and an outer surface, opposite the inner surface, and wherein the cover duct is arranged on the outer surface of the main body.

12. The marine outboard motor of any of claims 1 to 11, wherein every part of the cover duct is integrally formed with the main body of the protective cover.

13. The marine outboard motor of any of claims 1 to 11, wherein parts of the cover duct are formed integrally with the main body of the protective cover and form a first halfshell of the cover duct.

14. The marine outboard motor of claim 13, wherein the cover duct comprises a second half-shell removably attached to the first-half shell.

15. The marine outboard motor of claim 14, wherein the first half shell and the second half-shell comprise a plurality of corresponding mounting holes arranged to receive fastening members.

16. The marine outboard motor of any of claims 1 to 15, wherein the main body of the protective cover comprises a service opening configured to allow access to a top end of the internal combustion engine.

17. The marine outboard motor of claim 16, wherein the protective cover has a main body with an inner surface facing the internal combustion engine, in use, and an outer surface, opposite the inner surface, wherein the service opening extends between the outer and inner surface of the main body.

18. The marine outboard motor of claim 16, wherein the protective cover comprises a service flap covering the service opening.

19. The marine outboard motor of claim 18, wherein the service flap is pivotable between an operating position and a maintenance position.

20. The marine outboard motor of any of claims 1 to 19, wherein the protective cover has a main body with an inner surface facing the internal combustion engine, in use, and an outer surface, opposite the inner surface, and wherein reinforcement elements are located on the inner surface and/or the outer surface.

21. The outboard motor of claim 20, wherein the protective cover comprises sound insulating means attached to the inner and/or outer surface.

22. The outboard motor of any of claims 1 to 21, wherein the internal combustion engine comprises an engine block having first and second cylinder banks.

23. The outboard motor of any of claims 1 to 22, wherein the internal combustion engine is a diesel engine, particularly a turbo-charged or supercharged diesel engine.

24. A marine vessel comprising the outboard motor of claim any of claims 1 to 23.

25. An engine assembly comprising:

an internal combustion engine comprising at least one air duct configured to route intake air to the internal combustion engine; and a protective cover removably attached to the internal combustion engine, wherein the protective cover comprises a cover duct forming at least parts of the at least one air duct.

Intellectual

Property

Office

Application No: GB 1814994.8