Hybrid driven double pump

Abstract

A hybrid-driven dual pump for conveying a coolant for a combustion engine, is proposed. The dual pump comprises: a first pump assembly with a first pump impeller, a first spiral housing and a first pump shaft driven via a mechanical drive connection by a combustion engine; a second pump assembly with a second pump impeller, a second spiral housing, a second pump shaft and an electric drive; a joint pump housing enclosing the first pump assembly and the second pump assembly with a joint pump inlet and a joint pump outlet; and a flap arranged freely pivotably between an outlet of the first spiral housing and an outlet of the second spiral housing such that a direct flow connection between the first spiral housing and the second spiral housing is blocked.

Claims

1. A hybrid-driven dual pump for conveying a flow of coolant for a combustion engine, comprising: a first pump assembly with a first pump impeller having a radial outlet area, a first spiral housing a first pump shaft driven via a mechanical drive connection by a combustion engine, and a cylindrical regulating slide that is actuated a hydraulic circuit, transferable into an axial overlap with the radial outlet area of the first pump impeller, wherein the actuation of the cylindrical regulating slide is controlled by a proportional valve in the hydraulic circuit; a second pump assembly with a second pump impeller, a second spiral housing, a second pump shaft and an electric drive; a joint pump housing enclosing the first pump assembly and the second pump assembly with a joint pump inlet and a joint pump outlet that conveys a flow of coolant to the combustion engine; and a flap arranged freely pivotably between an outlet of the first spiral housing and an outlet of the second spiral housing such that a direct flow connection between the first spiral housing and the second spiral housing is blocked.

2. The hybrid-driven dual pump according to claim 1, wherein the first pump assembly and the second pump assembly further share a joint pump chamber in which the first pump impeller and the second pump impeller are accommodated.

3. The hybrid-driven dual pump according to claim 2, wherein the first pump impeller and the second pump impeller are arranged across from one another, facing one another in the pump chamber.

4. The hybrid-driven dual pump according to claim 2, wherein the pump inlet leads into the pump chamber between the first pump impeller and the second pump impeller.

5. The hybrid-driven dual pump according to claim 1, wherein the hydraulic circuit carries coolant as a hydraulic medium which is diverted from the flow of coolant.

6. The hybrid-driven dual pump according to claim 1, wherein the hydraulic circuit is conveyed by means of an axial piston pump driven reciprocally by the first pump impeller via a cam mechanism.

7. The hybrid-driven dual pump according claim 1, wherein a bearing of the second pump shaft and the electric drive are arranged axially overlapping one another.

8. The hybrid-driven dual pump according to claim 1, further comprising a pump control configured to, based on a received parameter, which is an indicator of a cooling requirement of the combustion engine, and a rotation speed of the combustion engine or of the first pump assembly, calculate control values for a displacement of the regulating slide and for a rotation speed of the second pump assembly, and drive the proportional valve as well as the electric drive as a function of the calculated control values.

9. A hybrid-driven dual pump for conveying a flow of coolant for a combustion engine, comprising: a first pump assembly with a first pump impeller having a radial outlet area, a first spiral housing, a first pump shaft driven via a mechanical drive connection by a combustion engine, and a cylindrical regulating slide that is actuated by a hydraulic circuit and transferable into an axial overlap with the radial outlet area of the first pump impeller; a second pump assembly with a second pump impeller, a second spiral housing, a second pump shaft and an electric drive; a joint pump housing enclosing the first pump assembly and the second pump assembly with a joint pump inlet and a joint pump outlet that conveys a delivery flow of coolant to the combustion engine; and a flap arranged freely pivotably between an outlet of the first spiral housing and an outlet of the second spiral housing such that a direct flow connection between the first spiral housing and the second spiral housing is blocked; wherein the hydraulic circuit is conveyed by means of an axial piston pump driven reciprocally by the first pump impeller via a cam mechanism.

10. The hybrid-driven dual pump according to claim 9, wherein the first pump assembly and the second pump assembly further share a joint pump chamber in which the first pump impeller and the second pump impeller are accommodated.

11. The hybrid-driven dual pump according to claim 10, wherein the first pump impeller and the second pump impeller are arranged across from one another, facing one another in the pump chamber.

12. The hybrid-driven dual pump according to claim 10, wherein the pump inlet leads into the pump chamber between the first pump impeller and the second pump impeller.

13. The hybrid-driven dual pump according to claim 9, wherein the hydraulic circuit carries coolant as a hydraulic medium which is diverted from the flow of coolant.

14. The hybrid-driven dual pump according claim 9, wherein a bearing of the second pump shaft and the electric drive are arranged axially overlapping one another.

15. The hybrid-driven dual pump according to claim 9, further comprising a pump control configured to, based on a received parameter, which is an indicator of a cooling requirement of the combustion engine, and a rotation speed of the combustion engine or of the first pump assembly, calculate control values for a displacement of the regulating slide and for a rotation speed of the second pump assembly, and drive the proportional valve as well as the electric drive as a function of the calculated control values.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Hereinafter, the invention is described by way of an embodiment, referring to the accompanying drawings, in which:

(2) FIG. 1 is a longitudinal sectional view through a hybrid-driven dual pump according to the invention;

(3) FIG. 2 is a plan view of the hybrid-driven dual pump according to the invention; and

(4) FIG. 3 is a perspective view of the hybrid-driven dual pump according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(5) FIG. 1 is a sectional view of the entire pump construction, which basically comprises a first pump assembly 1, a second pump assembly 2 and a joint pump housing 3. The pump housing 3 is arranged between the first pump assembly 1 and the second pump assembly 2, and encloses a pump chamber 30. Within the joint pump chamber 30, a first pump impeller 10 of the first pump assembly 1 and a second pump impeller 20 of the second pump assembly 2 are arranged opposite one another.

(6) The first pump impeller 10 is enclosed by a first spiral housing 31 as a portion of the pump housing 3. Likewise, on the opposite side of the pump chamber 30, the second pump impeller 20 is surrounded by a first spiral housing 32 as a portion of the pump housing 3. The first spiral housing 31 and the second spiral housing 32 lead to a joint pump outlet 35, formed as a housing opening. Upstream from the joint pump outlet 35, the first spiral housing 31 and the second spiral housing 32 each have an outlet opening, the cross-sectional planes of said openings extending at an acute angle to one another.

(7) Between the outlet opening of the first spiral housing 31 and the outlet opening of the second spiral housing 32, a flap 33 is arranged pivotably in the pump housing 3. The flap 33 may move in a freely pivotable manner within the acute angle between the cross-sectional plane of the outlet openings as far as a contact position against the outlet opening of the first spiral housing 31 or against the outlet opening of the second spiral housing 32 and block the outlet opening in question. The joint pump outlet 35 in the form of a housing opening is arranged within the pivot region between the contact positions of the flap 33.

(8) The flap 33 is flowed onto by a delivery flow of the first pump assembly 1 and a delivery flow of the second pump assembly 2 from each of the two sides. A position of the flap 33 along the pivot angle thus results from a pressure ratio between the two delivery flows. If the first pump assembly 1 is in operation and the second pump assembly 2 is not in operation, the delivery flow urges the flap 33 into the cross-sectional plane of the outlet opening of the second spiral housing 32 and closes said housing. This provides that the delivery flow from the first pump assembly 1 flows directly through the joint pump outlet 35 and does not arrive in the second spiral housing 32, in other words in an unpressurised output region of the second pump assembly 2. If the second pump assembly 2 is in operation and the first pump assembly 1 is not in operation, the delivery flow urges the flap 33 into the cross-sectional plane of the outlet opening of the first spiral housing 1 and closes said housing. This in turn provides that the delivery flow from the second pump assembly 2 flows directly through the joint pump outlet 35 and does not arrive in the first spiral housing 31, in other words in an unpressurised output region of the first pump assembly 1. If the first pump assembly 1 and the second pump assembly 2 are in operation, the flap 33 takes on an intermediate position along the pivot angle, causing both delivery flows to be guided out of the joint pump outlet 35 while preventing eddies from a direct convergence.

(9) The pump housing 3 further has a joint pump inlet 34. The joint pump inlet 34 is formed as a housing opening to the joint pump chamber 30, and is arranged in an axial region between the first pump impeller 10 and the second pump impeller 20 in the pump housing 3. Depending on the distribution of the pump power between the first pump assembly 1 and the second pump assembly 2, a coolant which flows through the joint point inlet 34 is sucked in a direction towards the first pump impeller 10 or in a direction towards the second pump impeller 20 or in both directions, and accelerated into the spiral housings 31, 32 by means of the radially acting blades of the pump impellers 10, 20.

(10) The first pump assembly 1 is driven via a belt drive by a combustion engine. The belt drive cooperates with a belt drive 12, which drives a first pump shaft 11 on which the first pump impeller 10 is fixed in the pump chamber 30. The first pump assembly 1 corresponds to a mechanically driven, regulatable centrifugal pump.

(11) The embodiment shown in FIG. 1 of the first pump assembly 1 has a hydraulically adjustable regulating slide 13, which is known from an ECF pump type. In this context, a flow-effective radial region around the first pump impeller 10 is variably covered by a cylindrical regulating disc 13, formed coaxial with the first pump shaft 11, along an adjustment path parallel to the first pump shaft 11. In FIG. 1, the regulating slide 13 is in an open position in which the flow region of the first pump impeller 10 is not covered.

(12) The first pump assembly 1 further comprises, within the radius of the first pump impeller 10, an axial piston pump 14, which is driven or reciprocally actuated by the first pump impeller 10 by way of a cam control system, in the form of a sliding show on a wobble plate on a rear face of the first pump impeller 10.

(13) The axial piston pump 14 sucks coolant in between the first pump impeller 10 and the regulating slide 13, and ejects the pressurised coolant into a hydraulic circuit 15 formed in the pump housing 3. The hydraulic circuit 15 comprises an electromagnetic proportional valve 16, shown in FIG. 2 and FIG. 3, and leads to an annular piston 17 arranged coaxial with the first pump shaft 11. The annular piston 17 takes on the function of a hydraulic adjustment member along the displacement path of the regulating slide 13.

(14) A restoring spring (not shown) acts on the annular piston 17 in the opposite direction to the pressure of the hydraulic circuit 15, in other words away from the first pump impeller 10. The annular piston 17 is connected to the regulating slide 13, and slides it in the direction of the first pump impeller 10 as the pressure of the axial piston pump 14 increases in the hydraulic circuit 15.

(15) The electromagnetic proportional valve 16 is opened without a driving current being supplied, in such a way that coolant sucked in by the axial piston pump 14 flows back substantially unpressurised via the hydraulic circuit 15 through the proportional valve 16 into the volume flow of the conveyed coolant. Thus, no pressure builds up in the hydraulic circuit 15, and the annular piston 17 remains in a base position under the action of the restoring spring. In this context, the regulating slide 13 is held in the open position, as is shown in FIG. 1.

(16) In the open position of the regulating slide 13, independently of a pump rotational speed given by the combustion engine via the belt drive, a maximum volume flow, dependent on the rotational speed, of the first pump assembly 1 is conveyed through the regulating slide 13 without shielding of a flow-effective region of the first pump impeller 10. This state also represents a failsafe mode, since in the event of a failure of a power supply, in other words an unpowered electromagnetic proportional valve 16, an unrestricted volume flow and a corresponding heat output at the combustion engine are ensured.

(17) If the electromagnetic proportional valve 16 is closed, the pressure applied by the axial piston pump 14 propagates via the hydraulic circuit 15 and acts on the annular piston 17. The annular piston 17 displaces the regulating slide 13 towards the first pump impeller 10 counter to the force of the restoring spring. In this context, the cylindrical regulating slide 13 is brought into axial overlap with the first pump impeller 10, causing an effective flow region of the first pump impeller 10 to be increasingly covered.

(18) In a closed position of the regulating slide 13, it completely covers the first pump impeller 10, in such a way that, as a result of the shielding, a conveyed volume flow of the first pump assembly 1 is reduced to a minimum or completely suppressed independently of the pump rotational speed.

(19) As is described above, a volume flow conveyed by the coolant pump depends both on the flow effectiveness of the first pump impeller 10, which decreases as the axial displacement of the position of the regulating slide 13 and of the annular piston 17 towards the closed position increases, with an increasing degree of coverage by the regulating slide 13. On the other hand, the conveyed volume flow of the coolant pump depends on the pump rotational speed, which underlies the fluctuations which are characteristic of vehicle operation.

(20) The pressure in the hydraulic circuit 15 is controlled by switch-on and switch-off durations for opening and closing the proportional valve 16 in such a way that an equilibrium between the hydraulic pressure and the pressure of the restoring spring in a position of the annular piston 17 or of the regulating slide 13 is achieved and maintained. The actual position of the annular piston 17 is detected by a travel sensor and used for regulating the proportional valve 16. Throttling of the conveying power of the first pump assembly 1 with respect to the predetermined rotational speed of the combustion engine is carried out by using pulse-width modulation to open and close the electromagnetically actuated proportional valve 16.

(21) The second pump assembly corresponds to an electrically driven centrifugal pump which is regulated in rotational speed.

(22) The second pump assembly comprises an electric motor 22 which is received in the pump housing 3. The electric motor 22 drives the second pump shaft 21, on which the second pump impeller 20 is fixed in the joint pump chamber 30. The electric motor 22 is a brushless DC motor comprising a permanent-magnet rotor, in the periphery of which permanently magnetic elements are embedded. The stator of the electric motor 22 has stator teeth which are distributed over the periphery and which are enclosed by respective windings of a stator coil. The electric motor 22 and the second pump shaft 21 have a joint bearing 23 for rotatable mounting with respect to the pump housing 3.

(23) The stator coils are actuated by a power circuit 24, which is connected to an electric power supply, so as to generate a rotational drive power with a predetermined rotational speed of the electric motor 22. The conveying power of the second pump assembly 2 thus depends on the controllable rotational speed of the electric motor 22.

(24) The hybrid-driven dual pump has a dedicated pump control system 4, which is arranged together with the power circuitry 24 of the electric motor 22 in a pump cover 36.

(25) The pump control system 4 determines whether a power requirement on a cooling power for the combustion engine, on which a switching process between operating modes of the hybrid drive of the coolant pump may be dependent, is increasing or decreasing, by way of connected sensors for measuring a temperature, such as a coolant temperature and/or an external temperature, a load, such as an outputted torque of the combustion engine, a rotational speed of the combustion engine, and/or further operating parameters of the vehicle, such as a gas pedal position, a fuel volume flow or the like. Alternatively, the pump control system 4 receives commands of a power requirement on the cooling power from a central control unit of the vehicle.

(26) In reaction to received or determined parameters, the pump control system 4 controls switching or a combination between the mechanical operating mode of the first pump assembly 1 and the electrical operating mode of the second pump assembly 2, as well as a conveying power distribution, by actuating the proportional valve 16 and by regulating the power circuit 24 in the electrical power supply of the electric motor 22.

LIST OF REFERENCE NUMERALS

(27) 1 First pump assembly 2 Second pump assembly 3 Pump housing 4 Pump control system 10 First pump impeller 11 First pump shaft 12 Belt pulley 13 Regulating slide 14 Axial piston pump 15 Hydraulic circuit 16 Proportional valve 17 Annular piston 20 Second pump impeller 21 Second pump shaft 22 Electric motor 23 Shaft bearing 24 Power circuit 30 Pump chamber 31 First spiral housing 32 Second spiral housing 33 Pivotable flap 34 Pump inlet 35 Pump outlet 36 Pump cover