WO2011035972A1

WO2011035972A1 - Electric delivery pump and method for driving an electric delivery pump

Info

Publication number: WO2011035972A1
Application number: PCT/EP2010/061290
Authority: WO
Inventors: Timo Steinbach; Alexander Fuchs
Original assignee: Robert Bosch Gmbh
Priority date: 2009-09-28
Filing date: 2010-08-03
Publication date: 2011-03-31
Also published as: DE102009045049A1

Abstract

The invention relates to an electric delivery pump for delivering a fluid, in particular for delivering fuel in a fuel injection system, which delivery pump 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 with a multiplicity 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

description

title

Electric feed pump and method for driving an electric feed pump

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.

DE 10 2006 007 554 A1 describes a delivery pump 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, over the

Circumference distributed. External magnetic field generators generate a running, rotating field changing, which causes the direct motor consequences of the rotor.

EP 1 600 635 A2 describes an internal gear pump 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 For this purpose, a separate filter heater is required in the known fuel injection systems, which, however, requires its own filter cartridge heater as well as an associated triggering, which, in terms of design, is also 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 Motor comprising a plurality of windings, which can be acted upon by electricity, to create 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 can be regulated as a function of 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 C0 _{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 of the fluid to be conveyed medium, in particular of the fuel by ström bar. 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-conditioned paraffin deposits can be avoided. According to yet another preferred embodiment, the windings of the plurality of windings are surrounded by the fluid medium to be conveyed. trömbar. 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 medium to be delivered 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 is a hydraulic diagram of a fuel injection system according to an embodiment,

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

Fig. 3 is a current-time diagram of an alternating current;

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

Fig. 5 is a current-time diagram of a mixed stream.

Embodiments of the invention

1, a hydraulic diagram of a fuel injection system 1 of an internal combustion engine according to an embodiment is shown. A regulated electric feed pump 2 pumps fuel from a fuel tank 3 via a line 4 to a high-pressure pump 5. The pumped by the high-pressure pump 5 fuel is conveyed via a high-pressure line 6 in a high-pressure accumulator 7. From the high-pressure accumulator 7, fuel can be injected via injection valves 8 into combustion chambers of the internal combustion engine (not shown). In the embodiment shown in FIG. 1, a filter 9 is arranged on the pressure side of the electric feed pump 2. An engine control unit 10 includes power electronics 1 1, which is connected to the electric feed pump 2 in order to control the power of the electric feed pump 2.

FIG. 2 shows a hydraulic diagram of a fuel injection system 1 of an internal combustion engine according to a further embodiment. The embodiment shown here differs from the embodiment shown in FIG. Guidance form in that the filter 9 is not arranged on the pressure side but the suction side of the electric feed pump 2. In addition, the filter 9 is combined with the electric feed pump 2. The electric feed pumps 2 arranged in each case in the fuel injection systems 1 illustrated in Figures 1 and 2 are in both cases of the so-called "integrated design." In this case, as already mentioned, the electric feed pump 2 is constructed such that it has a drive unit 12 and a drive unit Pump unit 13 includes, which are not shown in detail in the figures, but are only indicated schematically, which, however, as non-separable

Unit formed and arranged together in a housing 14. In addition, the electrical feed pumps 2 shown in Figs. 1 and 2 operate as follows. The drive of the regulated electric feed pump 2 is an electronically commutated motor (not shown in detail), which has windings which are permanently connected to a respective power output stage of the power electronics 1 1 and can be controlled as desired. For the drive of the electric feed pump 2, the windings are so energized that a circulating magnetic field is achieved. The alternating current is also added a constant proportion. In an extreme case at a standstill of the electric feed pump 2, this means that all windings are subjected to 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 deliberately impairing the efficiency of the engine, therefore, the desired heat output can be introduced into the fuel flowing around the windings, so that it is sufficiently heated so that no paraffin deposits caused by refrigeration can accumulate in the filter 9 or the paraffin deposits already present. No additional heating elements are required, and stepless regulation of the heating capacity, eg adapted to the ambient conditions, is also made possible.

Fig. 3 shows a current-time diagram of an applied to the electric feed pump 2 alternating current, which by a sinusoidal course of the Current-time curve is marked. Each of the curves indicates the alternating current applied to one of the plurality of windings 15, 15 ', 15 "of the motor 13. 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 arbitrarily controlled by the power electronics 1 1.

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

5 shows a current-time diagram of a mixed current applied to the electric feed pump 2. 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 on the stator for driving the motor, and at the same time the constant component in the multiplicity of windings 15, 15 ', 15 "is converted into heat.

In the case of the electric delivery 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 furthermore infinitely variable.

Claims

claims

Electric feed pump (2) for conveying a fluid medium, in particular for conveying fuel in a fuel injection system (1), which has a pump unit (13) and a drive unit (12), the pump unit (13) and the drive unit (12) being common in a housing (14) are arranged, and wherein the drive unit (12) comprises a motor with a plurality of windings (15, 15 ', 15 "), which can be acted upon by electricity, in particular to produce a rotating magnetic field,

characterized in that

the engine is operated with a mixed stream.

Electric feed pump (2) according to claim 1,

characterized in that

the engine is an electronically commutated motor.

Electric feed pump (2) according to claim 1 or 2,

characterized in that

the windings of the plurality of windings (15, 15 ', 15 ") are fixedly connected to a respective power output stage of a power electronics (11), which can be controlled as desired.

Electric feed 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 delivered, in particular by fuel. 5. Electric feed 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 conveyed.

Electric feed pump (2) according to one or more of claims 1 to 5,

characterized in that

on the pressure side of the electric feed pump (2), a filter (9) is arranged, or that on the suction side of the electric feed pump (2) a filter (9) is arranged.

Electric feed 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 feed 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 medium to be conveyed, in particular for heating the fuel.

Method for driving an electric feed pump (2) according to one or more of claims 1 to 8, wherein windings (15, 15 ', 15 ") of an engine are subjected to an alternating current in such a way 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 supplied with a constant current for generating heat.

0. Method according to claim 9,

characterized in that a fluid to be conveyed flows around the plurality of windings (15, 15 ', 15 "), wherein the fluid is heated simultaneously, and wherein the motor is an electronically commutated motor.