PETROL SUPPLY SYSTEM FOR AN INTERNAL COMBUSTION ENGINE Field of the Invention This invention relates, in general terms, to fuel systems for automotive internal combustion engines and, more specifically, said invention relates to mechanical fuel systems without BACKGROUND OF THE INVENTION Conventional fuel delivery systems include a tank, a fuel line, a filter, a pump, a pressure regulator and a fuel distributor. The fuel is carried in the fuel line by means of the fuel pump and then filtered to remove the large foreign particles. The pressure regulator regulates the fuel supply by diverting excess fuel to the tank while allowing a regulated amount of fuel to flow to the engine. The fuel is then filtered by a fuel filter, such as a cloth filter, before to reach the fuel distributor, where it is distributed to the cylinders »The primary disadvantage of this system is the constant recycling of unfiltered fuel, which causes an excess of wear of the fuel pump» The systems of the prior art claiming Overcoming these disadvantages employs a complex arrangement with numerous filters and numerous fuel lines located inside the tank. The disadvantages of these systems are numerous, including a high cost and difficulty in maintenance and repair. SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel supply system for filtering the return fuel that is less complex than conventional systems. This object is achieved, and the disadvantages of the approaches of the technique are overcome, above, providing a novel system for supplying combustion to an internal combustion engine. In a particular aspect of the invention, the system comprises a fuel tank for storing fuel, a fuel line, a fuel pump, a pressure regulator and a fuel filter. The fuel line has a first portion of fuel line and a second portion of fuel line. The first fuel line portion is partially integrated into the fuel tank and is connected to the fuel pump such that fuel can be supplied from the fuel tank to the engine. The first fuel line portion further includes a coaxial fuel line. The second fuel line portion communicates with the first fuel line portion to supply fuel to the engine. The system also includes a pressure regulator connected to the fuel line between the first fuel line and the second fuel line to regulate the fuel flow, in such a way that the fuel is supplied to the engine and the fuel is returned. in excess to the tank. A single fuel filter is connected to the fuel line between the first fuel line and the second fuel line to filter the fuel in such a way that both the fuel supplied to the engine and the fuel returned to that tank are filtered. In a preferred embodiment, the coaxial fuel lines include an outer tube and an axially aligned inner tube. The outer tube is used to supply fuel to the engine and the inner tube is used to return the unused fuel to the fuel tank. Another preferred embodiment, the pressure regulator and the fuel filter are integrated into a unitary device. An advantage of the present invention is that safety can be increased. Another advantage of the present invention is that the filter can be easily replaced. »Another advantage of the present invention is that a less complex and less expensive fuel system is offered. Other objects, features and advantages of the present invention will be readily apparent to the reader of this specification. Brief description of the drawings The invention will now be described, by way of example, with reference to the accompanying drawings, wherein; Figure 1 is a schematic view of a fuel system in accordance with the present invention. Figure 2 is a sectional view of a coaxial fuel line in accordance with the. present invention; 3 is a sectional view of an integrated fuel filter and pressure regulator according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel supply system 10, illustrated in FIG. 1, supplies fuel to a fuel. external combustion engine (not shown) through the fuel line 16 »The fuel pump 14 carries the fuel stored in the fuel tank 12 to the fuel line 16 to supply said fuel to the fuel distributor 20 where the fuel is distributed to the engine. The fuel that is being supplied to the steam is filtered and regulated by means of an integrated fuel filter / regulator 18 located along the fuel line 16 »The integrated fuel filter / regulator device 18 regulates the tzarrect quantity? Fuel, supplying the required amount to the engine and returning excess fuel to the tank 12 »An integrated filtering device / fuel regulator 18 also filters the fuel that is being supplied to the fuel distributor 20 and the fuel returned to the tank 12. Therefore all the fuel has a first pass filtration of 100%. In a preferred embodiment of the present invention, a fuel line 16 comprises three sections: the portion 16a comprising a pipe. of standard fuel line and having ends 17a and 17b; a portion 16b comprising a coaxial fuel line and having ends 19a and 19bp; and a portion 16c comprising a standard fuel line pipe positioned within the fuel tank 12 and having ends 21a and 21b. Referring now to Figures 1 and 2, the coaxial fuel line portion 16b comprises two concentrically aligned tubes, an inner tube 24 and an outer tube 26. The inner tube 24 includes a plurality of spacer elements 25 which cooperate with the tube. external 26 to form longitudinal slots 30 where the supply fuel can flow from tank 12 to filter / regulator 18 »In a preferred embodiment of the present invention, an integrated fuel filter / regulator device 18 is placed between sections 16a and 16b (see figure 1). Accordingly, an inner tube 24 is used to return unused filtered fuel from the filtering device / regulator 18 integrated to the fuel tank 12, the outer tube 26 is used to supply the fuel to the filtering / regulating device 18. of integrated fuel and the fuel line section 16a is used to supply a regulated amount of filtered fuel to the fuel distributor 20 »An integrated filter / regulator device 18 will be described in more detail below with reference to Figure 3» A The integrated filter / regulator device 18 includes a frame 52, which has a first end 53 and a second end 54 for housing a fuel filter 34 and a pressure regulator 44. The spacer 50 is placed in a frame 52 for. positioning there the regulator 44. A retainer 51 is fixed relative to a spacer 50 and a regulator 44 for receiving a filter end 34 »The frame 52 has an inlet 28 and a return hole 31 at a first end 53 , and an outlet orifice 40 in a second or tre or 54. A pressure regulator 44 is located adjacent the inlet orifice 28 and return orifice 30 while the filter 34 is located adjacent the outlet orifice 40. In the illustrated embodiment, in figure 3, a regulator part 40 forms return orifice 31 » An external pipe 26 of fuel line section 16b is connected to an inlet hole 28 of integrated fuel filter device / pressure regulator 18 »Fuel flowing from fuel tank 12 is supplied through slots 30 in the chamber 32 of the integrated filter / regulator 18 »The fuel then follows through a cylindrical filter 34 in an internal chamber 36» The fuel is then regulated by a regulator 44 in such a way that the required quantity of filtered fuel is supplied to the fuel distributor 20 through the outlet hole 40 connected to the fuel line portion 16a, and the excess filtrate fuel is returned to the fuel tank 12 through the return orifice 31 connected to the inner tube 24 of the coaxial fuel line 16b. A regulator 44 includes a frame 46 with openings 48, which communicate with an internal chamber 36. A spring 41 applies a predetermined pressure on a diaphragm 38. When the fuel pressure exerted by the fuel on the filter side of the diaphragm 38 exceeds a At the predetermined level, the diaphragm 38 is displaced, opening a valve 45 in such a way that the filtered fuel coming from the internal chamber 36 flows through the valve 45 in a passage 43 and leaves through the return hole 31 formed by the frame 46. While the preferred embodiment of the invention has been described in detail, persons with certain knowledge in the subject matter to which this invention refers will recognize several alternative designs and modalities, including the ones mentioned above, for practicing the invention defined in following claims »Particularly, the regulator na has to be integrated with the fuel filter»
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