KR20140018931A - Fuel injection system and tank installation unit for a fuel injection system - Google Patents

Abstract

The present invention relates to a fuel injection system, in particular a common rail system of an internal combustion engine, comprising an electric discharge pump for discharging a medium in fluid form, in particular for discharging fuel in the fuel injection system, wherein the electric discharge pump is electronically commutated. A drive device with a pump and a pump device are included, the drive device and the pump device forming an integral unit, and the electric discharge pump is matched to be arranged in a tank mounting unit mountable in the fuel tank of the fuel injection system. The invention also relates to a tank mounting unit for a fuel injection system, in particular a common rail system of an internal combustion engine, in which the fuel in the fuel injection system, in particular for discharging a medium in the form of a fluid, in or in the tank mounting unit An electric discharge pump for discharging the gas is disposed, wherein the electric discharge pump includes a driving device and a pump device having an electronically commutated motor, and the driving device and the pump device form an integrated unit.

Description

FUEL INJECTION SYSTEM AND TANK INSTALLATION UNIT FOR A FUEL INJECTION SYSTEM}

The present invention relates to a fuel injection system according to the preamble of claim 1 and a tank mounting unit for a fuel injection system according to the preamble of claim 9.

For example, an electric discharge pump for fuel discharge in a fuel injection system such as a common rail system, which is flanged to the motor shaft in the axial direction, with vanes and roller cell pumps on the one hand, is formed in a DC version as well as a "brush" Internal or external gear pumps with drive motors which are also formed in a brushless "DC version are used. This type of electric discharge pump includes a discharge and drive unit separated from each other. On the other hand, the prior art is known in the form of so-called integral structures in which the discharge and drive units are not provided separately from one another and are commonly provided in a housing as a non-separable unit.

The integral structure form is described for example in DE 10 2006 007 554 A1, wherein the discharge pump is integrated into the motor. The discharge pump includes a first cog wheel and a second cog wheel. The discharge chamber is formed between the two cog wheels. The center of the second cogwheel is supported on the mandrel. The first cogwheel is an external gear and forms a rotor, and the second cogwheel is an internal gear that engages in the eccentric center of the first cogwheel. The first cogwheel includes an bonded permanent magnet arranged to be distributed over the perimeter. The external magnetic field forming device forms an annular magnetic field that is changed by the rotor, which causes the rotor to directly act as a motor.

Further electrically driven internal gear pumps in the form of integral structures are also known from DE 10 2006 037 177 A1. The internal gear pump known in the publication includes an internal engagement tooth ring and an external engagement pinion that engages the tooth ring to form a discharge action, which pinion is rotatably supported on the bearing journal eccentrically to the tooth ring. The toothed ring and pinion are housed in the housing, and within the housing an electrical commutator stator is arranged, which stator extends concentrically about the toothed ring and, depending on the shape of the motor, surrounds the toothed ring concentrically. It interacts with an annular magnet that is rotatably connected with the tooth ring. In this case, the annular magnet executes a rotational motion together with the tooth ring to form the ejection action.

Such modifications known in the prior art are usually arranged in the high pressure pump of the direct fuel injection system or between the fuel tank and the high pressure pump upstream of the high pressure pump, which requires additional construction space.

Accordingly, there is a need to provide a space saving solution for the placement and positioning of electric discharge pumps for fuel discharge in fuel injection systems.

According to the invention there is provided a fuel injection system, in particular a common rail system of an internal combustion engine, comprising an electric discharge pump for discharging a medium in fluid form, in particular for discharging fuel in the fuel injection system. A drive device and a pump device with an electronically commutated motor, the drive device and pump device forming an integral unit, the electric discharge pump being matched for placement in a tank mounted unit mountable in a fuel tank of a fuel injection system. do. Due to the very compact structure in the axial direction of the integral type electric discharge pump, in which the drive device and the pump device form an integral unit, such a pump can be used even when the structural space conditions are very limited, for example in the case of a saddle tank. It can be mounted in the fuel tank without problem. In this case, the electric discharge pump can be mounted in a smaller, lower and optimum tank structure unit in accordance with the requirements, compared to conventional fuel pumps that require correspondingly long tank mounting units and thus correspondingly deep tanks. Can be. As a result of the installation of an electric discharge pump in the form of an integral structure in the fuel tank, further advantages are obtained as well as space savings. As such, for example through the axially shorter structural configuration of the electric discharge pump and thus likewise through the shorter tank mounting unit, the pump is a suction line or tank jet pump for the venturi nozzle after the fuel pump. Can be positioned in the fuel tank so that can be omitted. In addition, electronic rectification of the electric discharge pump is preferred because a much longer lifetime is achieved through the omission of a mechanical rectifying member. In addition, the electric discharge pump is more insensitive to vibration and other ambient influences.

According to one preferred embodiment, the electric discharge pump is mechanically fixable in the tank mounting unit or in the tank mounting unit, in particular by snap-in connections or by screw connections. This allows for a fast and cost-effective assembly.

According to another preferred embodiment, the electric discharge pump is loosely matched to be placed in the tank mounting unit.

According to another preferred embodiment, a filter is arranged on the suction side of the electric discharge pump.

Preferably this filter is washable via an intelligent control device. For this reason, the filter maintenance interval is preferably extended.

It is also particularly preferred that the electric fuel pump comprises at least one integral heating element. As such, paraffin deposits in diesel fuel are "thawed" or dissolved directly in the tank mounting unit without the need to heat the entire fuel tank for this purpose. Paraffin is not pumped into the low pressure system, which omits the installation of additional filter elements and thereby reduces costs.

According to another preferred embodiment, the electric discharge pump is formed as an internal gear pump.

Preferably the electronically commutated motor comprises a rotor and a stator, wherein the rotor is slidably supported directly inside the stator.

Furthermore, according to the invention there is provided a tank mounting unit for a fuel injection system, in particular a common rail system of an internal combustion engine, in which a fuel injection system, in particular for discharging a medium in fluid form, in or in the tank mounting unit is provided. An electric discharge pump for discharging the internal fuel is disposed, wherein the electric discharge pump includes a drive device and a pump device having an electronically commutated motor, and the drive device and the pump device form an integral unit. The tank mounting unit according to the invention with the electric discharge pump of the integral structure is mounted in the fuel tank of the direct fuel injection system as already described above, in particular to save space.

According to one preferred embodiment, the electric discharge pump is fixed in the tank mounting unit or to the tank mounting unit by snap-in connections or by screw connections. This allows a simple, quick and cost-effective assembly.

Embodiments of the present invention are described in more detail below with reference to the accompanying drawings.

1 is a view schematically showing a fuel injection system according to the prior art.
2 is a cross-sectional view illustrating a fuel tank of the fuel injection system according to the prior art.
3 is a cross-sectional view illustrating a fuel tank of the fuel injection system according to one embodiment.
4a and 4b schematically show possible measures for fixing an electric discharge pump in a tank mounting unit according to one embodiment.

1 schematically shows a fuel injection system 1 according to the prior art. The fuel is discharged from the fuel tank 5 to the high pressure pump 4 via the connection line 3 by an electric discharge pump 2 having a long axial length. An overflow valve 6 is arranged in the connecting line 3. The fuel tank 5, the electric discharge pump 2, and the connecting line 3 are subjected to low pressure, thus becoming part of the low pressure region of the fuel injection system 1.

The high pressure pump 4 is equipped with a pressure regulating valve 8 which is connected to the fuel tank 5 via a line 9. In addition, a high pressure line 10 is started from the high pressure pump 4 to guide the high pressure fuel to the high pressure accumulator 12, also called a common rail. The high pressure line 14 starts from the high pressure accumulator 12 under the insertion of the perfusion restriction 13, which directs the high pressure fuel from the high pressure accumulator 12 to the injection valves 15. In the figure only one injection valve 15 of these injection valves is shown for clarity. The high pressure line 10, the high pressure accumulator 12, the high pressure line 14, and the injection valve 15 contain fuel to which high pressure is applied, and thus are assigned to the high pressure region of the fuel injection system 1.

From the fuel injection valve 15 a return line comprising a first section 16 and a second section 17 is guided to the fuel tank 5. A pressure retention valve 18 is connected between the first and second sections 16, 17 of the return line. In addition, the pressure retention valve 18 is used to maintain a minimum pressure of about 10 bar in the first section 16 of the return line, which minimum fuel is independent of the operating state of the fuel injection system 1. Enables filling of the coupling chamber between the control valve member (not shown) and the piezo actuator (not shown) in the injection system 1. The operation of the fuel injection system 1 is controlled via the electronic control device 11. The high pressure accumulator 12 is provided with a pressure control valve 7 in connection with the return line. When the pressure in the high pressure accumulator 12 exceeds the preset maximum value, the pressure control valve 7 opens, and the excess pressure in the high pressure accumulator 12 drops to the low pressure region.

2 shows a cross-sectional view of a fuel tank 5 according to the prior art. The diesel fuel 19 is contained in the fuel tank 5. Further, in the fuel tank 5, a tank mounting unit 20 provided with an electric discharge pump 2 having a long axial length therein is disposed. Due to the long axial length of the electric discharge pump 2, the positioning of the tank mounting unit 20 likewise having a long axial length is limited to a small position in the fuel tank 5 with the corresponding axial length. Furthermore, the device according to the prior art, shown in this figure, requires the placement of a tank jet pump 21 in the fuel tank 5.

3 is a cross-sectional view of a cutaway fuel tank 5 according to one embodiment. The electric discharge pump 2 is a pump of a unitary structure, in which a drive device 22 and a pump device 23 having an electronically commutated motor (not shown) are shown as only schematically shown in this figure. The unitary unit 24 is formed. The electric discharge pump 2 in this case has a very compact structural form in the axial direction, which enables a correspondingly compact tank mounting unit 20, which can be arranged in a fuel tank in which the mounting possibilities are very limited. In addition, this makes it possible to arrange the tank mounting unit 20 in almost any position in the fuel tank 5, thus eliminating the need to provide an additional tank jet pump. It should be noted that electronic commutation generates high frequency currents that involve poor electromagnetic compatibility or complex line interruptions. Therefore, the output induction line of the power electronics to the drive device 22 should be kept as short as possible.

4a and 4b schematically show possible measures for fixing the electric discharge pump 2 in the tank mounting unit 20 according to one embodiment. In this case, the fixing of the electric discharge pump 2 is achieved through the so-called snap-in connections 25 and 25 'in a simple and quick manner, which snap-in connection reliably tanks the electric discharge pump 2. Hold in unit 20 (FIG. 4B). In assembly, the electric discharge pump 2 is simply inserted between the respective elastic clamping members 26, 26 ′ of the snap-in connection 25, 25 ′, wherein the elastic clamping members are bent outwardly. (FIG. 4A). Once the electric discharge pump 2 has reached its final position in the tank mounting unit 20, the elastic clamping members 26, 26 ′ regain their initial position and each latching protrusion 27, 27 ′ Thereby surrounding the upper side 28 of the housing 29 of the electric discharge pump 2 (FIG. 4B).

Therefore, the configuration according to the present invention makes it possible to quickly and simply assemble the electric discharge pump 2 at almost any position in the fuel tank 5.

Claims (10)

A fuel injection system 1, in particular a common rail system of an internal combustion engine, comprising an electric discharge pump 2 for discharging a fluid in the form of a fluid, in particular for discharging fuel 19 in the fuel injection system 1, The electric discharge pump 2 here comprises a drive device 22 and a pump device 23 with an electronically commutated motor, said drive device and pump device forming a unitary unit 24, the fuel of an internal combustion engine. In the injection system,
The fuel injection system (1) of an internal combustion engine, characterized in that the electric discharge pump (2) is matched to be arranged in a tank mounting unit (20) mountable in the fuel tank (5) of the fuel injection system (1). 2. The electric discharge pump 2 according to claim 1 is mechanically fixed in the tank mounting unit 20 or in the tank mounting unit 20, in particular by means of snap-in connections 25, 25 ′ or by screw connections. Fuel injection system (1) of an internal combustion engine. The fuel injection system (1) of the internal combustion engine (1) according to claim 1, characterized in that the electric discharge pump (2) is loosely matched to be arranged in the tank mounting unit (20). The fuel injection system (1) according to any one of claims 1 to 3, characterized in that a filter is arranged on the suction side of the electric discharge pump (2). A fuel injection system (1) according to claim 4, characterized in that the filter is washable via an intelligent control device. 6. The fuel injection system (1) of an internal combustion engine (1) according to claim 1, wherein the electric fuel pump (2) comprises at least one integral heating element. 7. The fuel injection system (1) of an internal combustion engine (1) according to any one of claims 1 to 6, characterized in that the electric discharge pump (2) is formed as an internal gear pump. 8. The fuel injection system of an internal combustion engine according to any one of claims 1 to 7, wherein the electronically commutated motor comprises a rotor and a stator, wherein the rotor is slidably supported directly inside the stator. (One). In a fuel injection system 1 of an internal combustion engine, in particular a tank mounting unit 20 for a common rail system,
In the tank mounting unit 20 or in the tank mounting unit 20, an electric discharge pump 2 is arranged for discharging the medium in fluid form, in particular for discharging the fuel 19 in the fuel injection system 1. In this case, the electric discharge pump 2 includes a drive device 22 and a pump device 23 having an electronically commutated motor, and the drive device and the pump device form an integrated unit 24. , Tank mounting unit 20 for fuel injection system of an internal combustion engine. 10. The electric discharge pump (2) according to claim 9, characterized in that the electric discharge pump (2) is fixable in the tank mounting unit (20) or to the tank mounting unit (20) by snap-in connections (25, 25 ') or by screw connections. A tank mounting unit 20 for a fuel injection system of an internal combustion engine.

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