Linear-Acting Electric Pump Unit and Method for Operating Said Unit

Abstract

A linear-acting electric pump unit and method for operating said unit. A linear-acting electric pump unit comprises an electromagnet and a pump unit. It is to be suitable for delivering gas/liquid mixtures. In order that it may be compactly assembled with other devices, it is to have a central inlet. The fluid delivered by the pump unit flows through the electromagnet and enters the pump unit on one side and leaves it on the other through the non-return valves, each arranged on the same centre line as the electromagnet. The pump unit can be used for delivery of gas/liquid mixtures, preferably in the sphere of combustion engines and their fuel supply systems and exhaust emission control systems.

Claims

1. A linear-acting electric pump unit, comprising: at least one electromagnet; and a pump unit driven by the electromagnet; wherein the pump unit comprising at least two non-return valves; wherein the fluid delivered by the pump unit flows through the electromagnet and enters the pump unit on one side and leaves it on the other through the non-return valves, each arranged on a same centre line as the electromagnet.

2. The linear-acting electric pump unit according to claim 1, wherein the electromagnet comprises at least a solenoid coil, a magnetic pole, a back iron, a magnet yoke and an armature, the armature being moveably supported on a tube, which also carries the fluid delivered by the pump unit.

3. The linear-acting electric pump unit according to claim 1, wherein the pump unit comprises a highly elastic bellows, which by a first moveable cover is deformed by an armature as the armature moves in opposition to the force of a return spring.

4. The linear-acting electric pump unit according to claim 1, wherein the pump unit comprises a cylinder and a moveable piston forming a seal therein, which is displaced by an armature as the armature moves in opposition to the force of a return spring.

5. The linear-acting electric pump unit according to claim 2, wherein when the solenoid coil is energized the armature runs into the magnetic pole and in so doing causes the pump unit to expel fluid from the second non-return valve, a return spring pushing the armature out of the magnetic pole once the solenoid coil is switched off and in so doing causing the pump unit to draw in fluid through the first non-return valve.

6. The linear-acting electric pump unit according to claim 2, wherein when the solenoid coil is energized the armature runs into the magnetic pole and in so doing causes the pump unit to draw in fluid through the first non-return valve, a return spring pushing the armature out of the magnetic pole once the solenoid coil is switched off and in so doing causing the pump unit to expel fluid from the second non-return valve.

7. The linear-acting electric pump unit according to claim 1, wherein the pump unit comprises a first non-return valve, which comprises a valve seat and a valve body, the valve body comprising a highly elastic disk and a centrally arranged holder.

8. The linear-acting electric pump unit according to claim 7, wherein the pump unit comprises a second non-return valve, which comprises a valve seat and a valve body, the valve body comprising a highly elastic disk and a centrally arranged holder.

9. The linear-acting electric pump unit according to claim 1, wherein an armature, at the end of its stroke with a solenoid coil in an energized state, is brought to a standstill by force of a return spring and reactive forces of the electric pump unit and that the armature, at the end of its stroke with the solenoid coil in an unenergized state, is likewise brought to a standstill by forces of the return spring and the electric pump unit.

10. A method for operating a linear-acting electric pump unit according to claim 1 wherein before commencing operation of the pump, an electrical control supplying the electric pump unit with electrical energy determines a coil temperature through a simultaneous measurement of an electrical current and an electrical voltage of a solenoid coil and in the event of a measured coil temperature below a predefined limit a solenoid coil is first activated by a high-frequency pulse signal, which does not produce any movement of an armature, but heats the solenoid coil, the measurement of an electrical resistance of the solenoid coil being regularly repeated and the actual pump operation being commenced at a lower frequency once the coil temperature exceeds the said predefined limit.

11. The method for operating a linear-acting electric pump unit according to claim 10 wherein the electric pump unit is supplied with electrical energy by an electrical control and is equipped with a pressure sensor, which has a fluid connection to an outlet of the electric pump unit and an electrical connection to the control the control monitoring the time profiles of the electrical current through the solenoid coil and the pressure on the outlet whilst the pump is in operation and comparing them with stored set values, and any malfunctioning of the solenoid coil, the electric pump unit or the pressure sensor being inferred from the comparison of the time profiles of the electrical current through the solenoid coil and the pressure on the outlet, and, where necessary, a fault message being sent to an overriding electrical control system.

Description

DRAWINGS

[0027] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0028] FIG. 1 shows the electric pump unit in section as an integral part of a larger device with unenergized electromagnet.

[0029] FIG. 2 shows the electric pump unit with energized electromagnet.

[0030] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

[0031] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0032] The linear-acting electric pump unit (1) according to FIG. 1 and FIG. 2 comprises an electromagnet (2) and a pump unit (3) driven by the electromagnet (2). Here the pump unit (3) comprises two non-return valves (5, 6), the fluid delivered by the pump unit (3) flowing through the electromagnet (2) and entering the pump unit (3) on one side and leaving it on the other through the non-return valves (5, 6), each arranged on the same centre line as the electromagnet (2).

[0033] The electromagnet (2) comprises a solenoid coil (7), a magnetic pole (8), a back iron (9), a magnet yoke (10) and an armature (11), the armature (11) being moveably supported on a tube (12), which also carries the fluid delivered by the electric pump unit (3).

[0034] In the embodiment according to FIG. 1 and FIG. 2 the pump unit (3) comprises a highly elastic bellows (4), which by a first moveable cover (13) is deformed by the armature (11) as the armature (11) moves in opposition to the force of a return spring (17).

[0035] In another embodiment, the pump unit (3) comprises a cylinder (15) and a moveable piston (16) forming a seal therein, which is displaced by the armature (11) as the armature (11) moves in opposition to the force of a return spring (17).

[0036] As represented in FIG. 2, when the solenoid coil (7) is energized the armature (11) runs into the magnetic pole (8) and in so doing causes the pump unit (3) to expel fluid from the second non-return valve (6), the return spring (17) pushing the armature (11) out of the magnetic pole (8) once the solenoid coil (7) is switched off and in so doing causing the pump unit (3) to draw in fluid through the first non-return valve (5).

[0037] In another embodiment, the armature (11) likewise runs into the magnetic pole (8) when the solenoid coil (7) is energized, but in so doing causes the pump unit (3) to draw in fluid through the first non-return valve (5), the return spring (17) pushing the armature (11) out of the magnetic pole (8) once the solenoid coil (7) is switched off and in so doing causing the pump unit (3) to expel fluid from the second non-return valve (6).

[0038] The pump unit (3) comprises a first non-return valve (5), which comprises a valve seat (24) and a valve body (25), the valve body (25) comprising a highly elastic disk (26) and a centrally arranged holder (27).

[0039] The pump unit (3) comprises a second non-return valve (6), which likewise comprises a valve seat (24) and a valve body (25), the valve body (25) comprising a highly elastic disk (26) and a centrally arranged holder (27).

[0040] The armature (11), at the end of its stroke with the solenoid coil (7) in the energized state, is brought to a standstill by the force of the return spring (17) and the reactive forces of the electric pump unit (3). At the end of its stroke with the solenoid coil (7) in the unenergized state, the armature (11) is likewise brought to a standstill by forces of the return spring (17) and the electric pump unit (3).

LIST OF REFERENCE NUMERALS

[0041] 1. electric pump unit [0042] 2. electromagnet [0043] 3. pump unit [0044] 4. bellows [0045] 5. non-return valve [0046] 6. non-return valve [0047] 7. solenoid coil [0048] 8. magnetic pole [0049] 9. back iron [0050] 10. magnet yoke [0051] 11. armature [0052] 12. tube [0053] 13. cover [0054] 14. cover [0055] 15. cylinder [0056] 16. piston [0057] 17. return spring [0058] 18. outlet [0059] 24. valve seat [0060] 25. valve body [0061] 26. disk [0062] 27. holder [0063] 29. pressure sensor [0064] 30. electrical control

[0065] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.