Note: Descriptions are shown in the official language in which they were submitted.
371~
FIELD OF T_E INVENTION
This invention relates to vehicle interior space
heaters of the type which are mounted on the vehicle and
use a portable form of fuel.
BACKGROUND OF THE INVENTION
. . .
Many types of vehicle heaters have been
developed. Arrangements for such heaters are disclosed
in United States patents 2,616,412, 3,072,176 and
4,105,158. The units are complex in nature and thus
expensive to manufacture and costly for the vehicle
owner. The units take up considerable space and because
of several moving parts, they are maintenance intensive.
A simpler construc~ion for a vehicle interior space
heater is disclosed in United States patent 3,690,549;
however, the heat exchange with the interior air is not
efficient and therefore requires a considerable size
burner to effect sufficient heating to warm the car
interior. In addition, there is no provision in this
arrangement for heating the coolant of the car engine
since the unit is adapted for use in the rear portion of
the car.
The interior space heater of this invention
overcomes the above problems in providing an economical,
efficient interior space heater which may be readily
adapted to also heat the engine coolant.
SUMMARY OF THE INVENTION
According to an aspect of the invention, an
auxiliary vehicle interior space heater comprises a
hollow metal housing with a plurality of metal tubes
extending generally parallel to each other and through
the housing. The tube ends are in communication with
the space exterior of the housing. A gas burner is
provided in the housing which uses a portable form of
fuel for heating the tubes. Means mounts the housing on
the interior wall of the vehicle with an opening to
place the tube ends in communication with vehicle
interior. The mounting means, when used on a vehicle
interior wall, positions the tubes to slant them
slightly upwardly towards vehicle interior. The gas
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burner heats the tubes to heat the air within and by
convection causes the heated air to enter a vehicle
interior. Means is provided for venting combustion
produc~s from the gas burner to exterior of the housing.
According to an another aspect of the invention,
a metal chamber may be provided in the housing. The
chamber would extend generally in the direction of the
tubes with the tubes proximate the chamber. The chamber
has an inlet and outlet extending exterior oE the
housing for connection to car engine coolant system.
The gas burner heats the char~er to warm the coolant in
the chamber and cause a flow of coolant through the
chamber via the inlet and outlet.
According to a preferred aspect of the
invention, a fan may be associated with the tube ends
for assisting the flow of air through the tubes and into
the vehicle interior. Means is provided for extracting
energy from the flow of the coolant to drive the fan.
BRIEF DESCRIPTION OF THE DRAWINGS
_
Preferred embodiments of the invention are shown
in the drawings wherein:
Figure 1 is an elevation of a car showing the
location of an interior space heater according to this
invention;
Figure 2 is a perspective view of the heater
having a portion cut away to show interior components
thereof;
Figure 3 is a vertical section through the
heater of Figure 2 in a direction perpendicular to the
heating tubes of the unit;
Figure 4 is a vertical section through the
heater unit of Figure 2 in a direction parallel to the
tubes of the heater unit; and
Figure 5 is a perspective view of the heater
unit as attached to the interior wall of a vehicle.
; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The heater, according to this invention, is
useful in many types of vehicles ranging from small cars
to large trucks and tractors used in industry. The
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heater may be mounted on an interior wall of any portion
of the car interior where space permi~s, such as the
rear wall of the vehicle or on the fire wall of the
vehicle. Referring to Figure 1, the ideal location of
the heater unit 10 is on the front fire wall 12 of the
vehicle 14. This is preferable when the heater unit 10
is adapted to heat the coolant of the vehicle engine 16.
Hoses 18 and 20 interconnect the heater 10 to the engine
coolant system where hose 18 is the inlet to the heater
and hose 20 is the outlet which delivers the heated
coolant or antifreeze to the engine block to maintain it
at an elevated temperature during cold weather.
It is obviously desirable to have a device to
heat the in-terior of the vehicle particularly when the
vehicle is not in use, such as the vehicle sitting
outside overnight. The heater is adapted to use a
portable form of fuel which is burned to provide the
necessary heat which is then heat exchanged with and
transmitted to the car interior 22. A thermostat 24 for
sensing the vehicle interior temperature may be use in
conjunction with an electronic or electrical controller.
The controller is programmed so that upon sensin~ an
interior temperature below a preset level, turns on the
heater 10 and commences warmin~ of the car interior.
Simultaneously if the heater unit 10 is connected to the
coolant of the motor 16, it will also commence heating
of the engine coolant.
It is appreciated with coolant arrangements that
valves are used to ensure that, when the engine is
operating, the coolant does not circulate through the
heater 10. Such valving arrangements are readily
understood by those skilled in the art for use on the
coolant system tubing.
Turning to Figure 2, details of the heater 10
are shown. The heater comprises a metal housing 26
which may be formed of sheet metal to withstand the
temperatures of operation of the unit. Within the metal
housing 26, there are a plurality of tubes 28 which,
according to this preferred embodiment, are provided in
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two rows namely row 28a and row 28b. The rows are
parallel to one another where the tubes themselves
extend paral]el to one another throuyh the metal housing
26. The tubes are pre~erably formed of metal, such as
copper which provide for an efficient transfer of heat
from the combustion gases to the air passing through
them. The tubes 28 comprise a set of first tube ends 30
and second set of tube ends 32 which are in
communication with the exterior of the housing 26.
According to this preferred embodiment, tube ends 32
extend slightly beyond the housing 26 to e~sure that
when mounted on the fire wall 12 of the vehicle they
extend into the interior of the vehicle. In addition,
such extension also assists in the convection flow of
warming air through the tubes in a manner to be
discussed with respect to Figure 4.
Located between the two sets of tubing 28a and
~8b is a metal chamber 34 which is used to heat the
coolant. Hose 18 leads into the chamber 34 in which a
check valve 36 is provided. The coolant is discharged
from the chamber 34 into hose 20 which leads eventually
back to the engine 16. According to this preferred
embodiment, the coolant passes along line 21 to a
turbine 38 emerging ~herefrom in the direction of arrow
2~ 40 for return to the engine 16. ~he purpose of the
turbine 38 is to drive the fan 42 which assists in
forcing the flow of air into the vehicle interior 22.
A portable fuel supply 44 for the gas burner 46
is provided. A line 48 delivers the gas to the burner
46 where an on/off valve 50 is pro~ided in line 48 to
control the flow of :Euel to the burner 46. According to
this embodiment, it is appreciated that various types of
fule may be used such as propane, natural gas, kerosene
and gasoline. The fuel supply 44 is preferably that of
propane which can be purchased in small propane bottles
and readily connected to line 48 by suitable couplings
52 as are well understood by those skilled in the art.
The burner 46 may be of the "pilot light" variety which
burns a minimum amount of gas and thus adds considerable
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life to each cylinder 4~ used. The pilot light has been
found to provide sufficient heat for heating the tubing
to heat the interior of the car and in addition to heat
the coolant of the car engine. Various forms of propane
pilot lights are a~ailable which are readily usable with
the cylinders 44 to give the necessary heat output.
As shown in Figure 3, the burner ~6 is located
beneath the lower ban]c 28b of the tubes. Flame 54
emerges from the pilot light 46, passing combustion
products over the tubes 28b in the directions of arrow
56. The combustion gases 56, after th~y pass over the
tubes 28b, pass upwardly through chamber 34 via channels
58 provided in the chamber 34. Such channels 58 are
provided completely through the chamber 34 as located in
several areas about the chamber 34 shown in Figure 2.
The combustion products continue upwardly through the
upper bank 28a of tubes in the direction of arrow 60 and
are then vented exterior of the metal housing 26 by way
of vent pipe 62 in the direction of arrows 64.
Appropriate piping may be provided to vent the gases
exterior of the or downwardly of the vehicle if desired.
In this manner, the tube banks 28a and 28b are heated
along with the coolant in spaces 66 of the chamber 34.
With the channels 58 extending through the chamber, the
coolant can pass through the chamber and be heated as it
comes in contact with the walls o~ the channels 58.
Check valve 36 ensures that the flow of coolant is
outwardly in the direction of arrow 21 to ensure a
continuous circulation of the coolant in that direction
so as to properly warm the engin~ block.
An electronic controller 68 is provided to
control the various functions of the heater. Controller
~8 has input from th2 temperature sensor via line 70.
Controller 68 controls valve 50 via line 72. Control to
the ignitor 74 is provided via line 76. The safety
device for sensing if the gas burner is operating 78 is
connected to the controller via wire 80. When the
controller 68 determines that the vehicle interior is
below a preset temperature, which may be programmed into
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the controller 68, it then turns on the ~as valve 50 by
sending a signal through line 72. Gas valve 50 may have
a solenoid control valve arrangement whereby an
electrical signal in line 72 opens the valve by
actuating a solenoid. Gas then ~lows to the pilot light
burner arrangement 46. An ignitor 74, which may be in
the form of a spark plug or the like, is then actuated
by an electrical signal in line 76 as controlled by
controller 68 to light the fuel. Air intake 82 is
provided to allow air to flow into the burner area to
provide the proper mixture of fuel to air for proper
combustion. The controller 68 may be programmed such
that after a predetermined period of time, approximately
10 seconds, if safety sensing d vice 78 determines that
a flame is not present, the controller shuts off the
valve 50 by way of a signal in line 72, The controller
68 may additionally be programmed to attempt a restart
of the burner in five minutes time. Additional
information may be programmed into the controller 68,
such as for example, after three attempts to light the
burner, then it shuts down and may light a warning light
or the like to indicate that the burner is faulty and
requires repair. An additional safety back-up may be
provided to cover the situation where the safety sensing
device 78 is malfunctioning and unlit fuel continues to
flow. A gas sensor may be located near the heater to
sense any uncombusted gases and sound an alarm i~ the
gaseous vapours exceed a safe level. Such gas sensors
are commonly used, particularly in sensing propane
leaks.
The flow of coolant through line 20 is direc-ted
to turbine 38. With the coolant flowing in the
direction of arrow 40, a fan 42 is power driven from an
output shaft of the turbine 38. The fan 42 is rotated
in a direction so as to cause a flow of air from intake
opening 84 through the tubes 28a and 28b to emerge in
the ~irections of arrows 86. Thus the energy imparted
to the coolarlt in heating the engine block is partially
tapped to drive the turbine to in turn cause the fan to
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assist in forcing warmed air into the car interior. In
the event that the vehicle interlor is of relatively
large volume, an additional vehicle interior space
heater may be provided at the rear of the vehicle, The
chamber 34 may be divided into two parts where the first
part handles the coolant from the engine. A hea-t
exchange medium may be provided in the second chamber
and by appropriate tubing connected to the additional
vehicle interior space heater. As the burner heats the
heat exchànge medium in the second chamber, it flows to
the additional vehicle interior space heater to exchange
the medium heat content with the vehicle interior.
It is appreciated that the outlet of the second
ends 32 of the tubing may be connected to car heating
ducts or the like to direct the warming air into the
interior. The tubes 28 may be sloped slightly upwardly
as shown in Figure 4 so that in the event that it is not
desired to use a ian arrangement 42, by convection the
combustion gases emerging from the burner 46 as they
heat the tubes 28 cause the heated air to flow in the
direction of arrows 86. This is obviously a ~esirable
arrangement when the unit does not incorporate the
chamber 34 for heating the coolant of the engine. Of
course depending upon the vehicle fire wall slope, the
slope of the tubes 28 in the housing 26 is determined to
ensure that when mounted on the fire wall the tubes have
the upward slope as indicated.
As shown in Figure 5 with the heater device 10
mounted on a vehicle wall 12, it may be totally encased
in the metal housing 26 with interior wall 88 separating
the cowling 90 for the fan from the interior of the
remainder of the housing 26. The intake 8~ for the fan
42 is provided in the wall of the housing 26. A
U-shaped bracket 92 may be used to firmly secure by way
of fasteners 94 the heating unit 10 to the fire wall 12.
The heating unit according to this invention
therefore provides an inexpensive device which may be
readily mounted to the vehicle interior wall to provide
multiple purpose forms of heating of not only the
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vehicle interior, but also the coolant of the engine. A
turbine may be used to derive energy from the Elow of
the coolant to in turn drive a fan which assists the
flow of air into the vehicle interior. It is
appreciated that the inlet for the fan may be coupled to
ducting which extracts air from the vehicle interior to
expedite the interior heating by a closed circuit flow
of air about the interior.
Although various preferred embodiments of the
invention have been described in detail, it will be
understood by those skilled in the art that variations
may be made thereto without departing from the spririt
of the invention or the scope of the appended claims.
