System for heating fuel oil

A mechanism (10) for heating diesel fuel in a diesel engine vehicle is disclosed. The mechanism (10) includes a heat exchange conduit (18), a portion of which is adapted to be held in the interior of a fuel tank (12) of a diesel engine (16). An inlet conduit (42) connects an inlet end (30) of the heat exchange conduit (18) to a water manifold (44) of the diesel engine (16). An outlet conduit (46) connects an outlet end (32) of the heat exchange conduit (18) to the engine block (48) of the diesel engine (16). In this manner, coolant liquid from the diesel engine (16) is passed through the heat exchange conduit (18) to heat diesel fuel contained in the fuel tank (12).

TECHNICAL FIELD 
The present invention relates broadly to devices for heating fuel oil prior 
to their passage to a combustion chamber. More specifically, the present 
invention relates to a heating system which heats diesel fuel within the 
fuel tank carried by a diesel engine vehicle. 
BACKGROUND OF THE PRIOR ART 
Diesel fuel, particularly No. 2 fuel oil, has the tendency to jell or "wax" 
in cold weather. This jelling of diesel fuel is a particularly acute 
problem in the trucking industry during the winter months in the northern 
portion of the United States and throughout Canada. During the winter 
months, temperatures and wind chill factors frequently reach minus 
30.degree. F. in these areas. In such a temperature and wind chill range, 
diesel fuel tends to jell or wax both in the fuel tank itself and within 
the fuel line leading from the tank to the engine. In the severest 
incidence of jelling, the diesel engine completely fails. The truck thus 
must be towed to a service area and the fuel tank heated. The towing and 
down time of the truck results in increased transportation costs. In less 
severe instances, the jelling can result in loss of power so that the 
trucks are forced to travel at a slow rate of speed. This also results in 
increased transportation costs. 
Numerous methods and apparatus have been used in the past in an attempt to 
solve this problem. A heating mechanism interposed in the fuel supply line 
from the fuel tank to the engine is one of the more frequently used 
mechanisms. U.S. Pat. No. 3,929,187 issued to Edwin E. Hurner illustrates 
such a mechanism. The device disclosed in the Hurner patent utilizes the 
heated water or coolant from the engine to supply heat to a heat exchanger 
through which a fuel line passes. Another prior art mechanism consists of 
a fuel filter which also serves as a heat exchanger to heat the fuel 
passing therethrough. Both of the above heat exchangers are relatively 
complex and, hence, expensive structures to produce. Also, since these 
heat exchange devices are disposed within the path of the fuel line and 
not within the fuel tank itself, they do not prevent the jelling or 
"waxing" of the diesel fuel within the fuel tank. 
The mixing of different types of fuel, as well as the use of additives to 
the fuel have also been attempted in an effort to prevent the jelling of 
diesel fuel at low temperatures. The use of additives requires that the 
additives be added at appropriate times and in appropriate amounts. Also, 
the additives tend to cause additional wear on the diesel engines. 
Another method utilized in the prior art to prevent the jelling of the fuel 
within a diesel fuel tank was by passing a portion of the exhaust pipe 
through the gas tank. However, this method does not provide the capability 
of heating the fuel prior to starting the engine. 
SUMMARY OF THE INVENTION 
The present invention is directed to a mechanism for heating diesel fuel in 
a diesel engine vehicle. The mechanism includes a conduit which has an 
inlet end and an outlet end. A means is provided for attaching the conduit 
to a fuel tank of a diesel engine vehicle such that a portion of the 
conduit is disposed in the interior of the fuel tank. The inlet end of the 
conduit is adapted to be connected in fluid communication with a water 
manifold of the diesel engine. The outlet end of the conduit is adapted to 
be connected in fluid communication with an engine block of the diesel 
engine whereby coolant liquid from the diesel engine is passed through the 
conduit to heat fuel contained in the fuel tank. 
In a preferred embodiment, the conduit is made of rigid tubing which 
includes a generally linear inlet section and a generally linear outlet 
section interconnected with one another and extending generally parallel 
to one another. The inlet and outlet sections each include a first portion 
adapted to extend generally downward into the fuel tank and a second 
portion extending transverse thereto and adapted to extend generally 
lengthwise within the fuel tank. By passing heated coolant through the 
conduit in the fuel tank, the fuel contained therein is kept at a 
sufficiently high temperature, even under extreme cold conditions, so that 
jelling is prevented. For example, in one test of the present invention, 
when the outside temperature was -30.degree. F., the temperature of the 
fuel within a fuel tank was kept at approximately 60.degree. F. 
In another embodiment of the invention, provision is made to heat the 
diesel fuel in the fuel tank prior to starting the diesel engine. In this 
embodiment, a "Southwind" type of heater is interposed between the inlet 
end of the conduit and the water manifold of the diesel engine. A first 
portion of inlet tubing extends from the water manifold of the diesel 
engine to an inlet of the "Southwind" heater. Another portion of the inlet 
tubing extends between an outlet of the "Southwind" heater and the inlet 
end of the conduit and passes heated water or coolant liquid to the inlet 
end of the conduit in the fuel tank. The "Southwind" heater is provided 
with its own pump to draw water from the water manifold when the diesel 
engine is not operating. The water is thus drawn to the "Southwind" heater 
and preheated therein. Since the water heated by the "Southwind" heater 
passes through the conduit in the fuel tank, the diesel fuel therein is 
heated prior to starting the engine. Unjelled fuel is thus supplied to the 
engine when it is started. 
Various advantages and features of a novelty which characterize the 
invention are pointed out with particularity in the claims annexed hereto 
and forming a part hereof. However, for a better understanding of the 
invention, its advantages, and objects obtained by its use, reference 
should be had to the drawings which form a further part hereof, and to the 
accompanying description in which there are illustrated and described 
preferred embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to the drawings in detail, wherein like numerals indicate like 
elements, there is shown in FIG. 1 a fuel heating device designated 
generally as 10. The fuel heating device 10 is shown installed with a fuel 
tank 12. The fuel tank 12 is attached to a conventional tractor-trailer 
cab 14. The fuel tank 12 is designed to hold diesel-type fuel which is 
supplied through a fuel line to a diesel engine 16. The heating device 10 
includes a heat exchange conduit 18, a portion of which is held within the 
interior of the fuel tank 12. The conduit 18 is formed of rigid tubing in 
the shape of a pair of L's extending parallel to one another. The conduit 
18 includes an inlet section 20 and outlet section 22. Each section 20, 22 
includes a first generally linear extending section 24 and a second 
generally linear portion 26 extending generally transverse thereto at a 
lower end of the first portion 24. A generally curved portion 28 of the 
conduit 18 interconnects the lower portions 26. The first portions 24 
extend parallel to one another, as do the second portions 26. An upper end 
30 of the inlet section 20 extends out of the tank 12 and forms an inlet 
end of the tubing 18. An upper end 32 of the outlet section 22 extends out 
of the tank 12 and forms an outlet end of the tubing 18. 
As is best seen in FIGS. 3 and 4, the heat exchange conduit 18 passes 
through a hole 34 formed through an upper portion of the fuel tank 12. The 
upper ends 30,32 are secured in a fluid-tight manner within holes in a 
mounting plate 36. The mounting plate 36 has a generally curved 
configuration which conforms generally to the shape of the outer surface 
of the tank 12. A fluid seal 38 is interposed between the outer surface of 
the tank 12 and the inner surface of the mounting plate 36 about the hole 
34. A plurality of machine screws 40 are used to tighten the mounting 
plate 36 down upon the seal 38 and the tank 12. The heating exchange 
conduit 18 is thus supported within the fuel tank 12. 
As best seen in FIG. 1, the first portion of the inlet section 20 extends 
generally downwardly within the tank 12 at a location slightly to the rear 
of the middle of the tank 12 in its lengthwise dimension. The portion 24 
of the outlet section 22 is similarly disposed. Also as seen in FIG. 1, 
the second portion 26 of the inlet section 20 extends generally along the 
lengthwise dimension of the tank 12 adjacent its bottom and extends on 
either side of the center thereof. The second portion 26 of the outlet 
section 22 is similarly disposed. This particular disposition of the heat 
exchange conduit 18 within the tank 12 has been found particularly 
advantageous. 
An inlet conduit 42 has one of its ends connected in fluid communication to 
the inlet end 30 of the heat exchange conduit 18 and its other end 
connected to a water manifold 44 of the diesel engine 16. The water 
manifold 44 is in turn connected in fluid communication to a water pump 
such that water is forced or pumped from the manifold 44 through the 
conduit 42 to the conduit 18. An outlet conduit 46 has one of its ends 
connected t the outlet end 32 of the heat exchange conduit 18 and its 
other end connected to a portion of the engine block 48 of the diesel 
engine 16. Water or coolant liquid thus flows back to the engine 16 
through the conduit 46. The conduits 42, 46 are preferably formed of a 
flexible material and are secured at their ends to the conduit 18, the 
water manifold 44, and the engine block 48 by conventional clamps 49. 
Another embodiment of a fuel heating device is shown in FIG. 5 and is 
designated generally as 10'. Elements of the device 10' which are similar 
to elements of the device 10 will be indicated by like primed numerals. 
The device 10' is illustrated in use with a conventional "Southwind" type 
of heater 50. The "Southwind" heater 50 is a standard type of heating 
device and is, therefore, shown only schematically. In the device 10', the 
coolant liquid does not flow directly through a single conduit to the 
inlet end 30' of the heat exchange conduit 18', but rather is first passed 
through the "Southwind" heater 50. A first inlet conduit 52 has an inlet 
end 54 connected in fluid communication with the water manifold 44' and an 
outlet end 56 connected in a fluid communication with a fluid pump 58 of 
the "Southwind" heater 50. A second inlet conduit 60 has an inlet end 62 
connected in fluid communication with an outlet of the "Southwind" heater 
50 and an outlet end 64 connected in a fluid communication with the inlet 
end 30' of the heat exchange conduit 18'. 
The device 10' operates in the following manner. When the diesel engine 16' 
and the coolant liquid therein are at a very low temperature such that 
starting of the engine 16' would be difficult, the "Southwind" heater 50 
is activated. A fluid pump 58 of the "Southwind" heater draws the coolant 
liquid from the water manifold 44' and through the conduit 52 to a heating 
section not shown but contained within the housing 66 of the "Southwind" 
heater 50. The heated coolant liquid is thereafter forced by the pump 58 
out of the "Southwind" heater 50 through the conduit 60 and into and 
through the heat exchange conduit 18'. Fluid contained in the fuel tank 
12' within which the heat exchange conduit 18' is disposed is thereby also 
heated. Thereafter, the coolant liquid is returned to the engine block 48' 
via the conduit 46. Once the engine 16' is started, the "Southwind" heater 
50 is shut down. The pump 58 is thus shut off, as is the heater of the 
heating section 66. Thereafter, the coolant liquid is forced through the 
conduit 52, the south wind heater 50, and the conduit 60 to the heat 
exchange conduit 18' under the force of the water pump of the engine 16'. 
Numerous characteristics and advantages of the invention have been set 
forth in the foregoing description, together with details of the structure 
and function of the invention, and the novel features thereof are pointed 
out in the appended claims. The disclosure, however, is illustrative only, 
and changes may be made in detail, especially in matters of shape, size, 
and arrangement of parts, within the principle of the invention, to the 
full extent extended by the broad general meaning of the terms in which 
the appended claims are expressed.