Marine propulsion – Screw propeller – Propulsion unit casing
Reexamination Certificate
1999-06-25
2001-09-11
Avila, Stephen (Department: 3617)
Marine propulsion
Screw propeller
Propulsion unit casing
Reexamination Certificate
active
06287161
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an outboard motor and more particularly to an improved protective cowling therefor.
As is well known, outboard motors generally include a power head that consists of a powering internal combustion engine and a surrounding protective cowling. The cowling is provided around the engine so as to provide a neater appearance and also to protect the engine from foreign materials. Of course, it is necessary that the protective cowling have an inlet opening arrangement so that air for combustion of the engine can enter the protective cowling in adequate quantities to maintain the desired maximum engine output. This gives rise to a number of problems.
First, it is important that the cowling inlet opening be positioned and configured in such a way that there can be adequate air flow to the engine so as to provide the desired output of the engine. However, because of the operation in close proximity to large bodies of water and since the water frequently may be sprayed upwardly by the operation of the watercraft into proximity with the inlet opening, there must be insurance against the ingestion of water through the inlet opening into the interior of the protective cowling where it could possibly damage the engine. Thus, arrangements have been provided that will assist in separating the water from the inducted air to prevent the water from entering into the interior of the protective cowling.
Although the goal is simple, the achievement of this goal is much more complicated. It is of course desirable to maintain a slim profile for the power head and also so as to avoid undue height. Thus, the space available for this air induction and water separation is quite restricted.
It has been proposed to employ various arrangements wherein a labyrinth type air flow path is provided between the atmospheric air inlet opening and the opening in the protective cowling that permits the air to enter the interior of the protective cowling. Such air flow paths, however, provide a reduced flow area and can restrict the output of the engine.
Also, there is a problem in connection with the draining of the separated water from the inducted air so that the water does not reenter the air stream and pass into the interior of the protective cowling. Generally, the air inlet openings are provided at the rear of the cowling and the drain passages for the return of the separated water from the cowling area is in proximity to the inlet opening. This provides significant problems in that the air flow may tend to sweep the separated water back into the interior of the protective cowling.
It is, therefore, a principal object of this invention to provide an improved air inlet device for the protective cowling of an outboard motor.
It is a further object of this invention to provide an air inlet arrangement or an outboard motor protective cowling that provides substantial separation between the air inlet opening for the induction system and the water drain for draining separated water from the inducted air before it passes into the interior of the protective cowling and into proximity with the engine.
In addition to the issue of avoiding restrictions in air flow, it is also desirable if the induction system provided in the cowling can provide an expansion chamber area. This will assist in not only maintaining good induction properties but also can assist in silencing the inducted air. However, if the expansion chamber volume is increased, then the exterior configuration of the protective cowling can be unduly bulky.
It is, therefore, a still further object of this invention to provide an improved intake arrangement for the protective cowling of an outboard motor that will provide sufficient expansion volume and will do this in such a way that the overall size of the cowling is not increased.
Because of the demand for larger and larger power outputs for outboard motors, the number of cylinders employed in the engine is substantially increasing. This gives rise to further expansion in the overall size of the protective cowling and also means that there is a greater engine displacement and hence more air is required for engine operation.
Furthermore, in order to improve the performance of the engine, it has been proposed to utilize such performance improving features like fuel injection systems. The fuel injection system may also be of the direct cylinder type which can provide further enhancements of engine operation. However, the use of fuel injection systems adds to the number of components that are contained within the protective cowling and this is further complicated when direct injection systems are employed.
The direct injection systems require not only a greater number of fuel injectors but also more complicated supply systems. The supply system becomes more complicated because higher pressures must be generated in direct injected engines and thus additional and high-pressure positively driven fuel pumps may become necessary.
All of these components are generally positioned in the area of the protective cowling that is contiguous to the air inlet area. This means that these delicate and sensitive components of the engine and specifically of its fuel injection system may become exposed to inducted water. Thus, the aforenoted problems with respect to water separation are even more important in connection with outboard motors having fuel injection systems and particularly direct injection systems.
Furthermore, the positioning of the inlet arrangement utilized with conventional outboard motor protective cowlings is such that the air is inducted in an area in close proximity to where many of the fuel injection system components are located. Thus, it is highly likely that any water in the inducted air will contact these components and cause potential problems.
It is, therefore, a still further principal object of this invention to provide an improved protective cowling arrangement and air inlet arrangement therefor that is particularly adapted for use with outboard motors having fuel injection and particularly direct cylinder injection.
The problems in conjunction with the prior art type of protective cowling arrangements can be best understood by reference to
FIGS. 1-3
. These figures show the main cowling member, indicated generally by the reference numeral
21
, of the type utilized with conventional prior art type of constructions. The main cowling member
21
is comprised primarily of two main components both of which may be formed from a suitable material such as a molded fiberglass reinforced resin or the like. These two components of the main cowling member
21
are detachably connected to a tray which is not shown and which with the main cowling member
21
encircles the powering internal combustion engine, which is not illustrated in these figures.
The main cowling member
21
is comprised of a main cowling portion
22
that has a generally inverted cup-shaped configuration and which defines an internal cavity
23
in which the associated engine is contained. The main cowling member
22
has an upper surface
24
that is formed with an indented portion
25
at the rear end thereof which is covered and enclosed by a closure member
26
that is connected to the main cowling member
22
in a suitable manner, such as by means of fasteners
27
. An upstanding inlet opening neck
28
that defines an internal passage
29
that communicates the chamber formed by the indented area
25
and the closure member
26
with the interior
23
of the protective cowling member
21
.
The closure member
26
is provided, as best seen in
FIG. 3
, with a plurality of slotted openings
31
formed in the rearward portion thereof that permit air to flow into the indented area
25
as seen by the arrows A in
FIGS. 1 and 2
. This air then flows around the inlet neck
28
and downwardly through the opening
29
into the cowling interior
23
for induction into the engine for combustion.
By utilizing the tuning neck
28
and the somewhat circuitous air flow path, water will tend to s
Avila Stephen
Beutler Ernest A.
Sanshin Kogyo Kabushiki Kaisha
LandOfFree
Cowling for outboard motor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cowling for outboard motor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cowling for outboard motor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2436776