Battery charging device installing structure for outboard motor

A battery charging device installing structure for an outboard motor wherein the outboard motor includes a power head having an internal combustion engine and a surrounding protective cowling. An alternator is driven by the engine and charges a remotely positioned battery through a rectifier that is mounted apart from the engine and on a highly heat conducting portion of the heat protective cowling for cooling of the rectifier.

BACKGROUND OF THE INVENTION 
This invention relates to a battery charging device installing structure 
for an outboard motor and more particularly to an improved mounting and 
cooling arrangement for the rectifier of an outboard motor battery 
charging system. 
It is well known with outboard motors, particularly those of the large 
displacement type, to employ a separate battery which battery is charged 
by an alternator which may form a portion of the magneto ignition system 
for the engine. Because of the alternating input current from the charging 
device, it is necessary to employ a rectifier for converting the 
alternating current into direct current to charge the battery. Frequently, 
a voltage regulator is also employed in conjunction with the rectifier. 
When used herein in both the specification and claims, the term 
"rectifier" is used generically so as to cover a rectifier per se or a 
rectifier regulator. 
Obviously, the rectifier becomes heated in its operation. As larger 
alternators are employed, the amount of heat generated by the rectifier 
increases significantly. It has been the practice to provide an 
arrangement for cooling the rectifier in outboard motor applications. This 
may be done by providing either cooling fins on the rectifier for air 
cooling or by placing the rectifier so that it will be in contact with the 
engine water cooling system and water cooled. However, both of these 
constructions have disadvantages. 
As the power output becomes larger, the dimension of the cooling fins also 
becomes larger. Quite obviously there is not adequate space in 
conventional outboard motors to accommodate such large finned rectifiers. 
In addition, the increase in the amount of finning can in some events 
actually interfere with the amount of cooling. 
Where the rectifier is water cooled, on the other hand, obvious corrosion 
problems can exist, particularly when operating in marine environments. As 
corrosion builds up on the rectifier outer surfaces, the heat transmission 
ability becomes reduced and overheating and eventual destruction of the 
rectifier can be a problem. 
It is, therefore, a principal object of this invention to provide an 
improved rectifier and mounting arrangement for an outboard motor wherein 
the rectifier will be cooled but no special cooling construction of the 
rectifier per se or involvement with the engine cooling system is 
required. 
It is a further object of this invention to provide an improved, simplified 
and highly effective arrangement for cooling a rectifier in an outboard 
motor battery charging system. 
SUMMARY OF THE INVENTION 
This invention is adapted to be embodied in a battery charging system for 
an outboard motor. The outboard motor includes a power head having an 
internal combustion engine and surrounding protective cowling. An 
alternator is driven by the engine and generates an alternating source of 
current. A rectifier is in circuit with the alternator and with a battery 
for charging the battery. In accordance with the invention, the rectifier 
is mounted within the power head but other than on the internal combustion 
engine and in heat exchanging relationship with a heat conducting material 
for cooling the rectifier.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION 
Referring first in detail to FIG. 1, an outboard motor is identified 
generally by the reference numeral 11. Since the invention relates to the 
charging system for a remotely positioned battery (not shown) which is 
conventionally positioned within the hull of the associated watercraft, 
only the power head of the outboard motor 11 is depicted and only the 
external construction of the components thereof need be illustrated and 
described. 
The power head includes an internal combustion engine 12 which may be of 
any known type and which is depicted as being of the in line three 
cylinder type operating on a two stroke crankcase compression principle. 
As is conventional with outboard motor practice, the engine 12 is disposed 
so that its output shaft rotates about a vertically extending axis. A 
flywheel magneto 13 is connected to the upper end of the output shaft in a 
known manner. 
The engine 12 is also provided with an induction system including a 
plurality of carburetors 14 that draw air from an air inlet device 15 and 
form a fuel/air mixture which is delivered to the crankcase chambers of 
the engine 12. This charge is then transferred to the combustion chambers 
and is fired by an ignition system including spark plugs 16 which are 
fired from the magneto generator 13 in a known manner. 
The power head of the outboard motor 11 is completed by means of a 
protective cowling which is comprised of a lower tray portion 17 and a 
main cover portion 18 that is detachably affixed to the tray portion 17 in 
a suitable manner. In accordance with a feature of the invention, the tray 
portion 17 is formed from a rigid, highly heat conductive material such as 
aluminum or the like as is adapted to be affixed to the upper end of a 
drive shaft housing, shown partially in FIG. 1, in any well-known manner. 
The main cowling portion 18, on the other hand, may be formed from a 
molded fiberglass reinforced resin or the like, as is well known in this 
art. 
In accordance with the invention, a rectifier, indicated generally by the 
reference 19, is provided with a flat lower surface 21 that is mounted on 
a flat upper surface of a boss or embossment 22 formed by the tray 17. 
Fasteners such as bolts or the like 23 serve to hold the rectifier 19 in 
good heat exchanging relationship with the boss 22 and tray 17. A 
conductor 24 conducts electricity from the alternator portion of the 
magneto generator 13 to the rectifier 19 for rectification and voltage 
regulation. The rectified and regulated direct current is supplied to the 
remotely positioned battery by means including a conductor 25. 
Because of the fact that the rectifier 19 is mounted remotely from the 
engine 12, it will not be heated by the heat generated in the operation of 
the engine 12. Furthermore, the open positioning of the rectifier 19 
within the interior of the protective cowling will permit it to be 
adequately cooled by air and by the heat transfer of the tray 17. In 
addition, water from the operation of the watercraft may further splash on 
the tray 17 to aid in its cooling. At the same time, however, the 
rectifier 19 is protected from this environment. Hence corrosion will not 
be a problem. 
FIG. 4 shows another embodiment of the invention which is generally similar 
to the embodiment already described. In this embodiment, however, heat 
transfer is further promoted by interpositioning a heat transfer plate 51 
between the rectifier 19 and the boss 22. The heat conductive plate 51 may 
be formed from a highly heat conductive material such as silicone, metal 
or the like so as to provide better terminal contact between the rectifier 
19, boss 22 and tray 17 and higher heat conductivity. 
It should be readily apparent the described embodiments are highly useful 
in maintaining good cooling for the rectifier without requiring cooling 
fins or the circulation of cooling water across the rectifier. Although 
two embodiments of the invention have been illustrated and described, 
various changes and modifications may be made without departing from the 
spirit and scope of the invention, as defined by the appended claims.