DE102009045049A1 - Electric feed pump and method for driving an electric feed pump - Google Patents

Abstract

The invention relates to an electric feed pump for pumping a fluid medium, in particular for pumping fuel in a fuel injection system, which has a pump unit and a drive unit, the pump unit and the drive unit being arranged together in a housing, and the drive unit having a motor with a Comprises a plurality of windings to which current can be applied, in particular in order to generate a rotating magnetic field, wherein the motor can be operated with a mixed current.

Description

The present invention relates to an electric feed pump and according to the preamble of claim 1 and a method for driving an electric feed pump according to the preamble of claim 9.

State of the art

As electric feed pumps for conveying fuel in a fuel injection system, such as in a common rail system, among other internal gear pumps, external gear pumps and vane pumps are used. In the prior art, these electrical feed pumps are usually flanged axially to a motor shaft and have separate conveyor and drive units.

In addition, in the prior art so-called integrated designs are known in which the conveyor and drive units are not provided separately from each other, but are provided together in a housing.

In DE 10 2006 007 554 A1 a delivery pump is described, which is integrated in an electric motor. The feed pump comprises a first gear and a second gear. Between the two gears, a delivery chamber is formed. The second gear is stored in its center on a thorn. The first gear is an external gear and forms the rotor, the second gear is an internal gear, which is entrained in the eccentric center of the first gear. The first gear comprises glued permanent magnets, which are distributed over the circumference. External magnetic field generators generate a rotating, rotating field which causes direct motor following of the rotor.

In EP 1 600 635 A2 An internal gear pump is described which has a pump section with an inner rotor formed on its outer periphery with teeth. An outer rotor has teeth formed on its inner periphery. Both rotors are housed in a housing.

However, the known in the prior art electric feed pumps, which are arranged for conveying fuel in a fuel injection system, but all additional heating elements in the fuel inlet to heat the fuel flowing through the electric pump, to the extent that in a pressure-side, for example arranged filter can not accumulate cold-induced paraffin deposits, or existing "thawed". For this purpose, a separate filter heating is necessary in the known fuel injection systems, which, however, makes its own filter cartridge heater and an associated control required. This is structurally complex consequently expensive.

Therefore, it is necessary to provide a structurally simple and inexpensive solution for heating the medium flowing through the electric feed pump, in particular for heating the fuel to be delivered in a fuel injection system.

Disclosure of the invention

Advantages of the invention

According to the invention, an electric feed pump for conveying a fluid medium, in particular for conveying fuel in a fuel injection system is provided which has a pump unit and a drive unit, wherein the pump unit and the drive unit are arranged together in a housing, and wherein the drive unit comprises a motor a plurality of windings, which can be acted upon by current to generate a rotating magnetic field. According to the invention, the engine is operated with a mixed stream. Since a constant proportion is added to the alternating current, on the one hand the efficiency of the electric feed pump is "worsened", however, heat is generated by the constant amount of heat for heating the medium to be conveyed and flowing around the windings. In the extreme case of a pump standstill, this means that all windings are supplied with a constant current. This produces no torque on the engine and the entire electrical power is converted to the plurality of windings in heat. The heating power achieved by the additional current supply with constant current is adjustable depending on the desired heating power. By means of the configuration according to the invention, in which the motor can be operated with an alternating current to which a constant current portion is added, the medium to be conveyed can be heated without additional components and electronic components, whereby a significant cost reduction is achieved. In addition, the heating power is infinitely variable and can be optimally adapted to the ambient conditions. This can be compared to a conventional heating system, which is always formed unregulated, energy and thus CO _{2 can be} saved. Thus, the configuration according to the invention also represents an environmentally friendly solution.

Preferably, the engine is an electronically commutated motor.

According to a preferred embodiment, the windings of the plurality of windings are fixedly connected to a respective power output stage of a power electronics, which is arbitrarily controllable.

According to a further preferred embodiment, the drive unit can be flowed through by the fluid medium to be delivered, in particular by the fuel. Due to the thermal connection of the drive unit, the fluid medium to be pumped is heated quickly and effectively without additional heating elements, so that accumulations of cold-caused paraffin deposits can be avoided.

According to yet another preferred embodiment, the windings of the plurality of windings can be flowed around by the fluid medium to be conveyed. This achieves a particularly effective and rapid heating of the fluid medium to be delivered.

Preferably, a filter is arranged on the pressure side of the electric feed pump. This embodiment is particularly advantageous because the already heated in the electric feed pump to be pumped fluid medium flows directly into the filter.

Also, the filter can be arranged on the suction side of the electric pump. This is advantageous, for example, in the case when the electric feed pump or electric fuel pump is combined with the filter and thus a heat transfer from the drive unit to the filter can take place.

Preferably, the electric feed pump is designed as a vane pump, internal gear pump or external gear pump.

It is also particularly advantageous if the plurality of windings serve as a heating element for heating the fluid medium to be conveyed, in particular for heating the fuel.

According to the invention, there is further provided a method for driving an electric feed pump in which a winding of a motor is so charged with an alternating current as to generate a torque on the motor and in which, in addition to being supplied with alternating current, the windings are supplied with a constant current Generating heat are applied. Thus, the fluid to be pumped medium can be heated quickly and effectively directly when flowing through the electric pump without providing additional heating elements or regulations.

Preferably, a fluid to be conveyed flows around the windings while being heated at the same time.

Moreover, it is preferred if the engine is an electronically commutated motor.

Brief description of the drawings

Hereinafter, embodiments of the invention will be described in more detail with reference to the accompanying drawings. It shows:

1 1 is a hydraulic diagram of a fuel injection system according to an embodiment;

2 a hydraulic diagram of a fuel injection system according to another embodiment;

3 a current-time diagram of an alternating current;

4 a current-time diagram of a direct current; and

5 a current-time diagram of a mixed flow.

Embodiments of the invention

In 1 is a hydraulic diagram of a fuel injection system 1 an internal combustion engine according to an embodiment shown. A regulated electric pump 2 pumps fuel from a fuel tank 3 over a line 4 to a high pressure pump 5 , The through the high pressure pump 5 Promoted fuel is delivered via a high pressure line 6 in a high-pressure accumulator 7 promoted. From the high-pressure accumulator 7 can fuel via injectors 8th in combustion chambers of the internal combustion engine (not shown) are injected. In the in 1 illustrated embodiment is a filter 9 pressure side of the electric feed pump 2 arranged. An engine control unit 10 includes power electronics 11 , which with the electric pump 2 connected to the performance of the electric feed pump 2 to control.

In 2 is a hydraulic diagram of a fuel injection system 1 an internal combustion engine according to another embodiment shown. The embodiment shown here differs from that in FIG 1 illustrated embodiment in that the filter 9 not on the pressure side but on the suction side of the electric feed pump 2 is arranged. In addition, the filter 9 with the electric pump 2 combined.

The respectively in the in 1 and 2 illustrated fuel injection systems 1 arranged electrical feed pumps 2 are in both cases of the so-called "integrated design". Here is the electric pump 2 as already mentioned, constructed such that it is a drive unit 12 and a pump unit 13 includes, which are not shown in detail in the figures, but are only indicated schematically, which, however, formed as a non-separable unit and together in a housing 14 are arranged. In addition, the work in 1 and 2 illustrated electric feed pumps 2 as follows. The drive of the regulated electric pump 2 is an electronically commutated motor (not shown in detail), which has windings fixed to a respective power output stage of the power electronics 11 are connected and can be controlled arbitrarily. For driving the electric pump 2 the windings are energized so that a circulating magnetic field is achieved. The alternating current is also added a constant proportion. In extreme cases, at a standstill of the electric pump 2 This means that all windings are supplied with a constant current. This produces no torque on the engine and the entire electrical power is converted into heat in the windings. If the constant component is added to the alternating current, a circulating magnetic field is generated in the stator to drive the motor and at the same time the constant component in the windings is converted into heat. By so to speak deliberate deterioration of the efficiency of the engine thus the desired heating power can be introduced into the fuel flowing around the windings, so that it is sufficiently heated so that no cold-related paraffin deposits in the filter 9 accumulate or that already existing Paraffinabscheidungen be "thawed". There are no additional heating elements required and a continuous control of heating power, z. B. adapted to the ambient conditions is also possible.

3 shows a current-time diagram of a to the electric pump 2 applied alternating current, which is characterized by a sinusoidal course of the current-time curve. Each of the curves indicates the one of the plurality of windings 15 . 15 ' . 15 '' the alternating current applied to the motor. In this embodiment, the rotating field is generated over three phases. As described above, each of the plurality of windings 15 . 15 ' . 15 '' connected to a respective power output stage and through the power electronics 11 arbitrarily controllable.

4 shows a current-time diagram of a to the electric pump 2 applied constant direct current, which is characterized by a linear course of the current-time curve. Will only DC to the drive unit 12 applied, this generates, as already described above, only heat, which across the plurality of windings 15 . 15 ' . 15 '' is discharged directly to the windings flowing around the fuel to heat it to a desired temperature.

5 shows a current-time diagram of a to the electric pump 2 applied mixed stream. The alternating current is thereby a constant proportion, which is represented by the dashed line added. At the same time, a circulating magnetic field is generated at the stator for driving the motor and at the same time the constant proportion in the multiplicity of windings 15 . 15 ' . 15 '' converted into heat.

At the electric pump 2 According to the invention, an effective heating for the fuel to be delivered is provided without additional components and electronic components, wherein the heating power is also infinitely variable.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102006007554 A1 [0004]
• EP 1600635 A2 [0005]

Claims (10)

Electric delivery pump ( 2 ) for conveying a fluid medium, in particular for conveying fuel in a fuel injection system ( 1 ), which is a pump unit ( 13 ) and a drive unit ( 12 ), wherein the pump unit ( 13 ) and the drive unit ( 12 ) together in a housing ( 14 ) are arranged, and wherein the drive unit ( 12 ) a motor with a plurality of windings ( 15 . 15 ' . 15 '' ), which can be acted upon by electricity, in particular in order to produce a circulating magnetic field, characterized in that the motor is operable with a mixed stream. Electric delivery pump ( 2 ) according to claim 1, characterized in that the motor is an electronically commutated motor. Electric delivery pump ( 2 ) according to claim 1 or 2, characterized in that the windings of the plurality of windings ( 15 . 15 ' . 15 '' ) fixed to a respective power output stage of a power electronics ( 11 ) are connected, which is arbitrarily controllable. Electric delivery pump ( 2 ) according to one or more of claims 1 to 3, characterized in that the drive unit ( 12 ) can be flowed through by the fluid medium to be pumped, in particular by fuel. Electric delivery pump ( 2 ) according to one or more of claims 1 to 4, characterized in that the plurality of windings ( 15 . 15 ' . 15 '' ) can be flowed around by the fluid medium to be delivered. Electric delivery pump ( 2 ) according to one or more of claims 1 to 5, characterized in that the pressure side of the electric feed pump ( 2 ) a filter ( 9 ), or that the suction side of the electric feed pump ( 2 ) a filter ( 9 ) is arranged. Electric delivery pump ( 2 ) according to one or more of claims 1 to 6, characterized in that the electric feed pump ( 2 ) is designed as a vane pump, internal gear pump or external gear pump. Electric delivery pump ( 2 ) according to one or more of claims 1 to 7, characterized in that the plurality of windings ( 15 . 15 ' . 15 '' ) serve as a heating element for heating the fluid to be conveyed medium, in particular for heating the fuel. Method for driving an electric delivery pump ( 2 ) according to one or more of claims 1 to 8, wherein windings ( 15 . 15 ' . 15 '' ) of a motor are subjected to an alternating current such that a torque is generated at the motor, characterized in that in addition to the application of alternating current, the windings ( 15 . 15 ' . 15 '' ) are applied with a constant current to generate heat. A method according to claim 9, characterized in that a fluid to be conveyed, the plurality of windings ( 15 . 15 ' . 15 '' ), wherein the fluid is heated simultaneously, and wherein the motor is an electronically commutated motor.

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