FI117349B - Fuel supply system - Google Patents

Abstract

Fuel supply system comprising at least a fuel source and a high-pressure pump in flow communication therewith for raising the fuel pressure up to an increased pressure, at least two fuel injectors arranged in conjunction with engine cylinders, each of which injectors is in flow communication with the high-pressure pump, and via a pressure accumulator unit. At least one pressure accumulator unit is in connection with both the fuel injector and at least one other pressure accumulator unit for fuel.

Description

117349

FUEL SUPPLY SYSTEM - BRÄNSLE TILLFÖRSEL SYSTEM

The invention relates to a fuel supply system according to the preamble of claim 1, comprising at least a fuel source and a high pressure pump in fluid communication therewith for raising the pressure of the fuel to elevated pressure, at least two fuel injection nozzles fitted in the fuel injection nozzle is connected to its own fuel pressure storage.

10 In order to improve the performance of piston engines, so-called "piston engines" a common rail fuel supply system with a distinction between pressure generation and injection control. In this way, fuel injection has been obtained e.g. more accurate in timing and volume. For large engines with more than six cylinders in the same row, for example, more than six cylinders, long pressure storage is required e.g. fuel pressure oscillation problems.

EP 968367 B1 discloses a fuel injection solution in which a large uniform space is divided into a pressure accumulator arranged in each of the high pressure 9 V ·: 20 channels leading to the injection nozzle. Although such a solution itself would reduce fuel pressure oscillation, it is not applicable to large, low viscosity fueled engines. When the engine is in Sammuk, each separate battery accumulates fuel which, when cooled, * * shrinks, and no longer has enough power when the engine is started to provide * * 25 runs.

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It is, therefore, an object of the present invention to provide a fuel supply system that minimizes the disadvantages of the prior art.

The objects of the invention are mainly achieved in the manner detailed in claim 1 and in the other claims.

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The fuel supply system of the invention comprises at least a fuel source and a high pressure pump in fluid communication therewith to raise the pressure of the fuel to the elevated pressure, and at least two fuel injection nozzles fitted to the engine cylinders pressure storage. The invention is mainly characterized in that at least one pressure reservoir connected to the injection nozzle is combined with both the fuel injection nozzle and at least one other fuel pressure reservoir. In the fuel flow direction 10, the last fuel pressure reservoir is in an adjustable flow relationship with the fuel source.

Preferably, more particularly in the invention, in the fuel flow direction, each of the latter fuel pressure reservoirs is in fluid communication with the boost pump 15 only in the direction of the fuel flow through the previous pressure reservoir. In the direction of the fuel flow, the last fuel pressure reservoir is in an adjustable flow connection to the fuel source through a separate return channel or the like and a valve fitted thereto. Preferably, the supply system comprises a plurality of pressure reservoirs, each of which is connected to a respective fuel injection nozzle and, except for the last one, a: V to the next pressure reservoir.

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The booster pump is substantially in direct flow communication with only one pressure reservoir, and the other pressure reservoirs are always connected to the pressure reservoir preceding each of the pressure reservoirs t1v 25. In this way, a coupling is achieved which enables efficient fuel recycling and at the same time effectively prevents the generation of pressure vibrations.

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The fuel supply system preferably comprises, after the booster pump 30, at least a third pressure reservoir through which all fuel to be supplied is: 1 ·. hated to pass.

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By means of the invention, it is possible to arrange the circulation of the fuel so that only very short ducts connecting the pressure reservoirs and the injection nozzles remain in the flow circuit. In this way, the fuel supply system can recycle most of the fuel, for example, to preheat the fuel before starting the engine 5. The solution provides close proximity to pressure reservoirs and injection nozzles for efficient and fast injection, and further combines this with the efficient fuel recycling of the coupling. This solution thus provides a very usable and inexpensive solution especially for low viscosity fuels. In addition, a uniform injection rate of 10 in each cylinder is achieved because the size of the injection valve per injection valve can be optimally sized. With such a solution the pressure oscillations are also very small.

The invention will now be described, by way of example, with reference to the accompanying drawing, in which Figure 1 schematically illustrates an embodiment of the invention.

The representation of Figure 1 is very schematic and comprises only the elements necessary to illustrate the basic idea of the invention. Reference numeral 1 illustrates the cylinders of a piston engine of the invention. Four of them are described here, «* *: but it is clear that the number of cylinders varies as well as it is clear V-engines have two rows of cylinders side by side. A fuel injection nozzle 2 is provided adjacent to each cylinder 1. The supply system comprises a 9 9 fuel source 3, such as a fuel tank, from which fuel is pumped through the fuel pipe 4 through a high pressure pump 5 to a pressure higher than the fuel source. The high pressure pump 5 is connected via the fuel line 8 to the pressure reservoir 6, through which * · * all the fuel to be fed. From the pressure reservoir 6 there is a connection in the direction of the fuel flow with the pressure reservoir 7.1 of the first injection nozzle 2.1. Also through this pressure reservoir 7.1, fuel passes to all injection nozzles 2.1 to 2.N. Jo-:! ·. 2.1 -2.N is equipped with its own pressure storage 7.1 - 7.N, • * · 999 9. ···. connected by a relatively short channel 9.1 - 9.N. The number of injection nozzles and • · 4 117349 pressure reservoirs thus varies depending on the engine, but in any case the pressure reservoir connected to the injection nozzle is combined with both the fuel injection nozzle and the second fuel pressure reservoir, except for the last pressure reservoir 8 of the importing fuel channel and 7 of the last pressure reservoir except for the part 8 of the fuel channel leading to the next pressure reservoir and at 9.1-9N of the fuel channel 9.1-9.N to the injection nozzle. A channel 9 is provided from the last pressure reservoir 7.N, leading back to the fuel source 3. A valve 10 is provided in the channel 9 which allows 10 to control the amount of fuel circulating through the system.

The invention is not limited to the embodiments shown, but several variations are contemplated within the scope of the appended claims.

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Claims (5)

117349 PATE NTT! SEE OURSELVES A fuel supply system comprising at least a fuel source (3) and a high pressure pump (5) in fluid communication therewith to raise the pressure of the fuel to elevated pressure, at least two fuel injection nozzles (2.1-2.N) arranged in connection with the engine cylinders (1). each injector nozzle (2.1-2.N) being in fluid communication with the high pressure pump (5), and each fuel injector nozzle (2.1-2.N) is provided with its own fuel pressure reservoir (7.1-7. N) and wherein at least one pressure nozzle is connected to the injector nozzle the grate (7.1) is connected to both the fuel injection nozzle (2.1) and at least one other fuel pressure reservoir (7.2), characterized in that in the fuel flow direction the last fuel pressure reservoir (7.N) is in an adjustable flow connection (9,10) to the fuel source (3). Fuel supply system according to claim 1, characterized in that in the flow direction of the fuel, each of the latter fuel pressure reservoirs (7.2) is in fluid communication with the booster pump (5) only in the direction of the fuel flow through the previous pressure reservoir (7.1). Fuel supply system according to any one of the preceding claims, characterized in that it comprises a plurality of pressure storages (7.1-7.N), each of which is connected to a respective fuel injection nozzle (2.1-2.N) and a fuel stream. - • · · in the reverse direction except the last (7.N) to the next pressure accumulator. • · Fuel supply system according to Claim 3, characterized in that the boost pump (5) is substantially in direct flow communication with only one pressure reservoir (7.1) and the other pressure reservoirs are connected at least always to the pressure reservoir upstream of each: M · «· f ft Fuel supply system according to any one of the preceding claims, * * *: characterized in that it comprises, after the booster pump (5), at least a third pressure reservoir (6) through which all the fuel to be supplied is fitted; * Chemistry. »» · • · • * ··· 117349