Mounted fuel tank heater

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fuel tank normally provided with the vehicle or other

MOUNTED FUELTANK HEATER device powered by such engine. The system includes a

TECHNICAL FIELD

heat exchanger which is installed in the fuel tank of the vehicle or other device. In the preferred embodiment,

This invention relates to a system for preheating fuel 5 the heat exchanger is installed through and secured to for an internal combustion engine in the fuel tank nor the opening normally provided in the fuel tanks of most mally provided with a vehicle or other machine pow diesel engine-powered over-the-road trucks for installa ered by such engine. tion of a fuel gauge. Most such trucks are provided with BACKGROUND ART 10 two fuel tanks and the fuel gauge access opening is usually only used for a fuel gauge in one of the tanks.

It is well known that preheating the fuel used in an Therefore the unused opening in one of the tanks can be internal combustion engine improves the efficiency of used for installation of the present invention. the engine. Further, preheating the fuel typically used In the preferred embodiment, the heat exchanger is in a diesel engine can avoid serious fuel flow problems 15 an elongated substantially cylindrically shaped device well known to occur in cold weather environments. made of a thermally conductive material, preferably a Diesel fuel, and in particular the No. 2 fuel oil typi corrosion resistant metal. The heat exchanger includes a cally burned by the engines of over-the-road trucks, can heated fluid chamber and a fuel tube extending through congeal or "wax' in the cold weather regularly experi such chamber. The heated fluid chamber includes an enced during the winter months in the northern states of inlet port and an outlet port positioned in a first end the United States and in Canada. The jelling or waxing 20 portion of the heat exchanger. A divider plate is pro of fuel can shut a diesel engine down, necessitating the vided towing of the vehicle to a repair facility where the fuel outlet inport the heated fluid chamber between the inlet and tank must be heated to alleviate the problem. The ex the chamberwhich extends from the first end portion of through all but a small portion of the pense of towing and downtime can be substantial.

A number of methods and devices have been devel- 25 length of the chamber. The divider plate divides the oped in an attempt to solve the problem of congealing heated fluid chamber into an inlet section and an outlet fuel oil in cold weather. One method has been to install section whereby heated fluid from an external source a heater in the fuel line. U.S. Pat. No. 3,929, 187 dis enters through the inlet port and travels through the closes a device which utilizes this method. However, inlet section toward the second end portion of the this method does not solve the problem of fuel oil con 30 chamber where it passes into the outlet section and gealing within the fuel tank itself before it even gets into travels back toward the first end portion where it exits the fuel line. Another method is to install a heater in the through the outlet port and is returned to the external fuel tank. U.S. Pat. No. 4,237,850 discloses a device source for reheating. Heat is transferred through the which utilizes this second method. The device disclosed external walls of the heat exchanger from the heated in this patent has two primary disadvantages. One, 35 fluid to the fuel in the fuel tank.

while the fuel can be heated in the tank to a temperature As indicated above, a fuel tube is provided which above that at which it "waxes', it is not necessarily extends through, and is therefore surrounded by the heated to a temperature which will prevent it from heated fluid chamber. In the preferred embodiment, fuel congealing in the fuel line in extremely cold weather, is drawn into an open fuel inlet end of the tube proxi because of the volume of fuel which must be heated in 40 mate and external to the second end portion of the heat the tank which is usually directly exposed to the cold exchanger and is drawn through the fuel tube where it outside air temperatures. Second, the device disclosed is further heated by the heated fluid in the above in this patent requires an access opening which must be described chamber which surrounds the fuel tube and cut/formed into the top of the fuel tank prior to installa exits from the fuel outlet end of the tube which is con tion of the device. 45

Therefore, it is a principal object of the present inven ent nected to the fuel line of the vehicle in which the pres tion to provide a system for preheating diesel fuel in the firstinvention is installed, proximate and external to the end portion of the heat exchanger.

fuel tank to a temperature above that at which the fuel In the preferred embodiment, the external source of would normally congeal. heated fluid is the radiator of the vehicle in which the It is a further object of the present invention to pro- 50 present invention is installed. Fluid communication can vide a system for preheating the diesel fuel leaving the fuel tank to a temperature which is sufficiently higher be provided between the radiator and the inlet and than the temperature at which the fuel would normally outlet ports of the above-described heated fluid cham congeal such that the fuel cannot jell in the fuel line ber via flexible hoses similar to those normally used in between the fuel tank and the diesel engine to which it 55 internal combustion engines to provide fluid communi is supplied. cation between the radiator and the engine block. In It is yet another object of the present invention to another embodiment of the present invention, the provide a system for preheating the fuel in the fuel tank heated fluid can comprise lubricating oil circulated of a diesel engine-powered vehicle or machine which from the oil pan of the engine with which the system is includes a heat exchanger which can be installed 60 used.

through and secured in the opening normally provided Fuel is drawn from the fuel tank through the fuel tube in such a fuel tank for the installation of a fuel level of the present invention into the fuel line as described gauge. above by the fuel pump of the engine of the vehicle or DISCLOSURE OF THE INVENTION 65 other device in which the system is installed. Other objects and advantages will be accomplished BRIEF DESCRIPTION OF THE DRAWINGS by the present invention which provides a system for FIG. 1 illustrates a perspective view, partially cut preheating fuel for an internal combustion engine in the away of a system for preheating fuel for an internal

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combustion engine in a fuel tank constructed in accor of the heat exchanger 12, as indicated by the arrows dance with various features of the present invention. 50A and 50B. The heated fluid travels down through FIG. 2 illustrates a top view in section of the heat the inlet section 36 of the heated fluid chamber 26 and exchanger, taken at 2-2 of FIG. 1, of a system for under the distal end portion 42 of the divider plate 40 preheating fuel for an internal combustion engine con into the outlet section 38 of the heated fluid chamber 26, structed in accordance with various features of the as indicated by the arrows 50B, 50C, and 50D. The present invention. heated fluid exits the outlet section 38 of the chamber 26 FIG. 3 illustrates a front elevation view of an alter through the outlet port 30 via an appropriate fitting 46, nate embodiment of a system for preheating fuel for an as indicated by the arrows 50E and 50F. It will be ap internal combustion engine in a fuel tank constructed in 10 preciated by those skilled in the art that heat from the accordance with various features of the present inven heated fluid will be transferred to the fuel in the fuel tion. tank which surrounds the heat exchanger 12, which FIG. 4 illustrates a block diagram of a system for preferably is constructed of a corrosion resistant metal preheating fuel for an internal combustion engine in a which has good thermal conductivity. In the preferred fuel tank constructed in accordance with various fea 15 embodiment, the heated fluid comprises heated coolant tures of the present invention as illustrated in FIGS. 1 supplied from and returned to the radiator of the vehi and 2. cle or other device in which the system 10 is installed as FIG. 5 illustrates a perspective view, partially cut illustrated by the block diagram illustrated by FIG. 4. It away, of another embodiment of a system for preheat will be appreciated by those skilled in the art that fluid ing fuel for an internal combustion engine in accordance 20 communication can be provided between the radiator with various features of the present invention. and the inlet and outlet port fittings, 44 and 46 respec BEST MODE FOR CARRYING OUT THE tively, by hoses, indicated by the reference numerals INVENTION 52A and 52B in FIG. 4, similar to those typically used between a radiator and the block of an internal combus

A system for preheating fuel for an internal combus 25 tion engine.

tion engine in the fuel tank normally provided with the Also, as indicated with dashed lines in FIG. 4, the vehicle or other device powered by such engine is illus hoses 52A and 52B could be alternately connected to trated generally at 10 in FIG. 1. The system includes a the oil pan of the internal combustion engine for the heat exchanger shown generally at 12 in FIG. 1. The circulation of lubricating oil as the heated fluid for the heat exchanger 12 is installed through an access opening 30 heating of the fuel.

14 which is normally provided in fuel tanks for diesel Still referring to FIGS. 1 and 4, it can be seen that engine-powered over-the-road trucks for installation of fuel from the fuel tank enters the fuel tube 32 through a fuel gauge. A portion of such a fuel tank is illustrated the open fuel inlet end 48 of the tube 32, as indicated by at 16 in FIG. 1. The heat exchanger 12 is provided with the arrow 60A, and exits through the fuel outlet end 54 a flange 18, which is dimensioned and predrilled to 35 of the tube 32, proximate and externally of the first end match the flange 20 surrounding the opening 14 in the portion 2 of the heat exchanger 12, as indicated by the fuel tank 16, proximate a first end portion 22 of the heat arrow 60B. The outlet end 54 of the fuel tube 32 com exchanger 12. When the system 10 is installed, an appro municates with the fuel line, indicated by the line 60 in priate gasket or seal (not shown) is installed between the the block diagram illustrated in FIG. 4, which supplies flange 18 and the flange 20. fuel to the engine. It will be appreciated by those skilled The heat exchanger 12 comprises a substantially cy in the art that the fuel entering the fuel line will have lindrical vessel having an outer wall 24 which defines an been further heated in the fuel tube 32 by the heated interior heated fluid chamber 26. An inlet port 28 and an fluid in the chamber 26 which surrounds the tube 32. outlet port 30 are provided proximate the first end por Referring to FIG. 3, an alternate embodiment 10' of tion 22 of the heat exchanger 12, between the first end 45 the system of the present invention is illustrated. In the portion 22 and the flange 18, through which a heated system 10, the heat exchanger 12 comprises a U-shaped fluid is supplied from and returned to an external source tube secured proximate its inlet and outlet openings, 28' of the heated fluid. A fuel tube 32 extends axially and 30', respectively, to a flange 18' which may be through the heat exchanger 12 from externally of its secured to a fuel tank 16 in a manner similar to that second end portion 34 to externally of its first end por 50 described for the system 10 illustrated in FIGS. 1, 2 and tion 22. The fuel tube 32 is surrounded by the heated 4.

fluid chamber 26 as shown in FIGS. 1 and 2. The heated Referring now to FIG. 5, another alternate embodi fluid chamber 26 is divided into an inlet section 36 and ment 10" of the system of the present invention is illus an outlet section 38, as illustrated in FIG. 2, by a divider plate 40, comprised of two coplanar plate sections 40A 55 trated. In the system 10", the heat exchanger 12" com prises an elongated substantially cylindrical vessel hav and 40B positioned between the fuel tube 32 and the ing a similar overall external appearance to the heat outer wall 24 of the heat exchanger 12. The divider exchanger 12 of the system 10 illustrated in FIG. 1. plate 40 extends from the first end portion 22 of the heat However, in this embodiment, there is no fuel tube exchanger 12, parallel to the fuel tube 32, for all but a extending through the heat exchanger 12" as in the small portion of the length of the heat exchanger 12 system 10; in this system 10", fuel is drawn from the where it terminates in a distal end portion 42, such that bottom of the fuel tank in the conventional manner, i.e. fluid communication is provided between the inlet sec fuel line connections in the vehicle or other device in tion 36 and the outlet section 38 of the heated fluid which the system is used are left undisturbed. The heat chamber 26 proximate the second end portion 34 of the exchanger 12" defines a heated fluid chamber 26' and heat exchanger. 65 includes a heated fluid inlet port 28' coaxially (with the Referring to FIG. 1 and to FIG. 4, which is a block longitudinal axis of the heat exchanger 12") positioned diagram of the system 10, it can be seen that heated fluid in the first end portion 22" of the heat exchanger. A enters via an appropriate fitting 44 into the inlet port 28 heated fluid inlet tube 70 is provided which extends

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coaxially through the heat exchanger 12" from an inlet tion of said heat exchanger being contained within end 72, positioned externally of and proximate the first said fuel tank;

end portion 22" of the heat exchanger 12", through the said heat exchanger defining an inlet port and an inlet port 28", to an open outlet end 74 positioned outlet port proximate a first end portion of said within the heated fluid chamber 26" proximate the sec heat exchanger positioned externally of said fuel ond end portion 34" of the heat exchanger, such that tank;

heated fluid in the inlet tube 70 flows into the heated a heated fluid chamber defined by said heat ex fluid chamber 26", as indicated by the arrows 50". In changer communicating between said inlet and this embodiment, heated fluid from an external source outlet ports, said heated fluid chamber including a (as described above for the system 10) enters the inlet 10 divider plate which separates said heated fluid end 72 of the inlet tube 70, flows down through the tube chamber into an inlet section communicating with 70 and out of the outlet end 74 into the chamber 26' said inlet port and an outlet section communicating proximate the second end portion 34" of the heat ex with said outlet port, said divider plate being posi changer 12", and back toward the first end portion 22' tioned such that a heated fluid entering said inlet of the heat exchanger where it exits through the outlet 15 port flows toward a second end portion of said heat port 30', as indicated by the arrows 50A", 50' and exchanger where said heated fluid flows through 50B". The heat exchanger 12" includes a flange 18' said outlet section of said heated fluid chamber and which may be secured to a fuel tank 16 in a manner exists through said outlet port; similar to that described for the system 10 illustrated in a source of said heated fluid; FIG.1. It will be appreciated by those skilled in the art 20 means for providing fluid communication between that, because of the flow path of the heated fluid, the said source of heated fluid and said inlet and outlet greatest heat transfer from the heated fluid to the fuel in ports of said heat exchanger; the fuel tank will occur near the second end portion 34" said heat exchanger further comprising a fuel tube of the heat exchanger 12". Since the heat exchanger is passing substantially axially through said heated installed through an opening normally provided in the 25 fluid chamber and forming a portion of said divider top portion of the fuel tank, the second end portion 34" plate, said fuel tube having a fuel inlet end posi of the heat exchanger will be positioned near the bottom of the fuel tank from which fuel is drawn into the fuel tioned externally of said heated fluid chamber line. Therefore, heating of the fuel entering the fuel line proximate said second end portion of said heat is enhanced. This embodiment of the present invention 30 exchanger in fluid communication with said fuel in also has the advantage of having improved heat transfer said fuel tank, and said fuel tube having a fuel outlet characteristics over prior art systems which utilize a end positioned externally of said heated fluid cham U-shaped tube heat exchanger similar to that shown in ber proximate said first end portion of said heat the system 10' illustrated in FIG. 3. Heat transfer from exchanger in fluid communication with said fuel the heated fluid to the fuel in the fuel tank is increased 35 line of said internal combustion engine; because of the relatively large surface area provided by whereby said fuel in said fuel tank is heated by heat the external walls 24 of the heat exchanger 12' as com transferred from heated fluid contained within said pared to the U-shaped tube devices. heated fluid chamber through the walls of said heat In light of the foregoing, it can be seen that a system exchanger; and 10 is provided by the present invention for preheating 40 whereby fuel drawn from said fuel tank through said the fuel for an internal combustion engine in the fuel fuel tube into said fuel line is further heated by heat tank 16 by a heat exchanger 12 installed through an transferred from heated fluid contained by said access opening 14 in the fuel tank. Heat from a heated heated fluid chamber which surrounds said fuel fluid which is supplied to the heat exchanger 12, as tube.

indicated by the arrows 50, is transferred to the fuel in 45 2. The system of claim 1 wherein said source of the fuel tank 16. The fuel is further heated by the heated heated fluid comprises a radiator containing a coolant fluid as it is drawn through the fuel tube 32 into the fuel which communicates with a block of said internal com line 60. Accordingly, when the system 10 is installed in bustion engine for cooling said engine. a vehicle or other device powered by an internal com 3. The system of claim 1 wherein said source of bustion engine, the efficiency of such engine will be 50 heated fluid comprises an oil pan of said internal com improved. In particular, the system 10 will eliminate or bustion engine.

minimize the problem of congealing or "waxing' of 4. A system for preheating fuel for an internal com diesel fuel in a diesel engine-powered vehicle or other bustion engine of a vehicle having a fuel line, said vehi device operated in cold weather environments. cle being equipped with a fuel tank for storing fuel to be While a preferred embodiment has been shown and 55 supplied to said fuel line, said fuel tank provided with an described, it will be understood that it is not intended to access opening in an upper portion thereof, which com limit the invention to such disclosure, but rather it is prises:

intended to cover all modifications and alternate con an elongated shell member defining an exterior sur structions falling within the scope of the invention as face of a heat exchanger, said shell member in defined in the appended claims. 60 stalled through and secured to said access opening I claim: with a first substantial portion of said shell member 1. A system for preheating fuel for an internal com disposed within said fuel tank and a second portion bustion engine having a fuel line comprising: disposed exterior said fuel tank, said shell member a fuel tank for storing fuel to be supplied to said fuel provided with an inlet port and an outlet port in line, said tank having an access opening provided 65 said second portion exterior said fuel tank, said in an upper portion thereof; shell member having a lengthwise axis; an elongated heat exchanger installed through and a top closure for said second portion of said shell secured to said access opening, a substantial por member exterior to said fuel tank;

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a bottom closure for said first portion of said shell outlet portion joined at said distal end of said di member; vider plates;

a fuel tube mounted axially within said shell member, a source of heated fluid; and said fuel tube extending through and sealed to said means for providing fluid communication between top and bottom closures of said shell member, said said source of heated fluid and said inlet and outlet fuel tube having an open first end proximate said ports of said shell member whereby said heated bottom closure, said open first end having commu fluid flows into said shell member through said inlet port into said inlet portion, through said outlet nication with said fuel tank, and an open second portion and out through said outlet port to thereby end proximate said top closure for connection with O transfer heat from said heated fluid to fuel in said said fuel line; fuel tank, and whereby said heated fluid flowing a pair of oppositely disposed divider plates disposed through said shell member transfers heat into fuel axially within said shell member extending from flowing through said fuel tube from said fuel tank said top closure to a distal end positioned near said to said fuel line.

5. The system of claim 4 wherein said source of bottom closure, said divider plates attached to and 15 heated fluid comprises a radiator containing a coolant extending radially to said fuel tube and further which communicates with a block of said internal com attached to said top closure, said divider plates bustion engine for cooling said engine. forming an inlet portion within said shell member communicating with said inlet port and an outlet heated fluid comprises an oil4 pan 6. The system of claim wherein said source of of said internal com portion within said shell member communicating bustion engine.

with said outlet port, said inlet portion and said