EP1963637B1 - Controllable coolant pump - Google Patents

Abstract

The pump has an annular valve pusher (4) on several piston rods movable in the housing (1) in piston guides. There is an annular piston (12) opposite the valve pusher. A clamping cover (18) is pressed against the housing, which contains one or more pressure connection borings (20) ending in pressure connectors (19).

Description

The invention relates to a controlled via a pulley controllable coolant pump for internal combustion engines according to the preamble of claim 1.

In the prior art controllable coolant pumps for internal combustion engines are described, which are driven by a pulley from the crankshaft of the internal combustion engine and in which the impeller is switchable, for example in connection with a friction pair, driven by the pump shaft.

The applicant was in the patent DE 100 57 098 C1 a proven controllable coolant pump, in which stationary in the pump housing, a magnetic coil is arranged which arranged with a rotatably, but spring loaded slidably disposed on the drive shaft, impeller side provided with a friction lining armature disc in operative connection, that when the magnetic field due to the Federanpresskraft rotatably on the drive shaft arranged impeller is taken from the armature disk.

Since the driving torque is strongly limited by the available magnetic space in this design, this solution has been consistently developed.

The application based on this solution DE 102 35 721 A1 describes a space-optimized controllable coolant pump, with one of the friction disc of the magnetic coupling to the impeller transmissible, significantly increased drive torque.

This increased drive torque is caused by an increase in the contact force, which results from the fact that between the friction disc and the impeller by a inflow ring and a Ausströmring for the cooling medium builds up a pressure assisting vacuum, and at the same time the friction disc clutch during operation by means of overflow openings with the Pressure of the cooling medium applied.

By means of realizable with such coolant pumps two-step control, the cooling capacity as well as the drive power of the coolant pump can be varied.

However, optimal control of the power of cooling and cooling of automotive coolant pumps should allow for forced cooling commencing immediately upon starting the engine, thereby increasing the engine's warm-up phase with all the disadvantages encountered during this phase, such as increased friction losses, increased emissions and an increased fuel consumption can be significantly reduced.

In order to allow such a short-term engine warming with the resulting advantages, the drive of the coolant pump was disengaged during cold start of the engine with the aforementioned types.

Now had the engine reached its operating temperature, the respective friction clutch, with this clutch design own function-related wear problems, activated and turned on the drive of the coolant pump.

In the process, a large amount of cold coolant was pumped into the engine heated to the operating temperature so that it immediately cooled down considerably.

However, the desired benefits of a rapid heating of the engine were partially compensated.

When switching on larger coolant pumps were also due to the required mass acceleration to overcome very high torques, which inevitably had a high component load result.

In the US 48 28 455 Now, a solution has been described in which by means of a slotted, axially movable disk, the effective blade width of the impeller could be changed.

From the DE 199 01 123 A1 is also known a controllable coolant pump with an open impeller and an adjustable slide with slotted axially movable floor, in which by means of electrically, hydraulically or pneumatically actuated displacement of the slide, the effective blade width of the impeller can be varied.

However, one of the major drawbacks of both of the aforementioned designs is that slotted slides can only be used in conjunction with simply curved, open paddle wheels.

However, such simply curved paddles inevitably have a lower efficiency.

Another type of slider was developed by the applicant in the DE 103 14 526 A1 presented. This is an electromagnetically operated, in the suction region of a coolant pump working valve spool.

In the case of large pump units in plant and energy engineering, other types of valve gate valves (see "The Centrifugal Pumps" by C. Pfleiderer, Springer-Verlag, 4th edition (1955), page 422) are used.

These known as slit valve designs are arranged concentrically to the impeller, axially displaceable valve spool which in the closed position, the outlet of the liquid from the impeller in the To prevent pressure spiral and be used to shut off the flow.

In the DE 881 306 C For example, such an axially movable, spring-loaded, hydraulically adjustable, operating in the pressure range gap slide is described, which is able to severely limit the delivery volume flow under spring action when using the differential pressure of Radseitenraumes.

However, these solutions of the centrifugal pump technology are unsuitable for use as a coolant pump in automotive engineering, as u.a. For example, the slide closes due to the spring action, so that a failure of the control inevitably means a failure of the coolant pump and further functioning of the coolant pump after failure of the scheme (fail-safe) can not be guaranteed.

In addition, the guides in this design are always the operating medium with the inevitable contamination load of the cooling medium such. Foundry sand, metal particles and the like, e.g. exposed from the manufacturing process or due to wear, so that dirt particles which get into the guide inevitably lead to jamming of the slide.

In addition, with the previously described in the prior art sliders in the closed state no "zero leakage" can be realized.

In the course of the continuous optimization of internal combustion engines in terms of emission and fuel consumption, however, it is increasingly important to bring the engine as soon as possible to operating temperature after the cold start, on the one hand to minimize the friction losses (with increasing oil temperature decreases its viscosity and thus the friction of all oil lubricated Components) to reduce the emission values (since only after the so-called "light-off temperature", the catalysts are effective, affects the period until reaching this temperature, the exhaust emission) in order to simultaneously reduce fuel consumption.

Tests in engine development have shown that a very effective means of engine warming is "standing water" or "zero leakage" during the cold start phase.

During the cold start phase, the cylinder head should by no means flow through coolant to bring the exhaust gas temperature as fast as possible to the desired level.

Vehicle manufacturers demand leakage currents of less than 0.5 l / h ("zero leakage").

The studies on the fuel consumption of internal combustion engines in motor vehicles have shown that by consistent thermal management, ie those measures which lead to an energetically and thermomechanically optimal operation of an internal combustion engine, about 3 to 5% fuel can be saved.

Therefore, taking into account these aspects, an increasingly precise control of the coolant flow rate as a function of the temperature of the enforced coolant is absolutely necessary.

This objective should also be realized with the least possible material and cost.

The invention is therefore based on the object to develop a driven, controllable coolant pump for internal combustion engines, which avoids the aforementioned disadvantages of the prior art, in case of failure of the regulation further functioning of the coolant pump (fail-safe) ensures, by a high efficiency, a characterized by a very compact, simple, robust design and which ensures high reliability and reliability even in loaded with contaminated medium operating fluid, an active control of the coolant flow rate on the one hand by "zero leakage" to ensure optimum heating of the engine and on the other hand after heating of the engine to influence the engine temperature in continuous operation so accurately that throughout Work area of the engine both the pollutant emission as well as the friction losses and fuel consumption can be significantly reduced.

According to the invention this object is achieved by a controllable coolant pump with the features of the main claim of the invention.

The controllable coolant pump according to the invention with a pump housing (1), a pump housing (1) mounted, driven shaft (2), on a free, flow-side ends of this shaft (2) rotatably mounted impeller (3) and a pressure-actuated valve spool (4) with an outflow region of the impeller (3) variable overlapping outer cylinder (5), characterized in that the valve slide (4) is annular, wherein the valve spool (4) a plurality of piston rods (6) are arranged in the pump housing (1) are distributed parallel to the shaft (2) evenly over the circumference of the valve slide (4) associated with the valve spool (4) piston rods (6), a plurality of bores (7) introduced at the valve slide side end in the pump housing (1) seal receivers (8 In which rod seals (9) are arranged, wherein at the opposite end of the bores (7) in the pump housing (1) has an annular groove (10) a is arranged which connects the holes (7) to each other, and in the bores (7) piston guides (11) are arranged, in which the valve slide (4) arranged piston rods (6) are mounted axially displaceable, wherein in the piston guides (11 ) arranged with their ringnutseitigen ends to each other by means of an annular piston (12), said in the annular groove (10) is slidably mounted, ringnutseitig are in the pump housing (1) between the holes (7), uniformly over the circumference the annular piston (12) distributed spring chambers (13) introduced in which against the annular piston (12) tensioned compression springs (14) are arranged.

This arrangement according to the invention of an annular valve slide (4) arranged on piston rods (6) and guided in sealed piston guides (11) in the pump housing (1) and actuatable via an annular piston (12) is a very compact, simple and robust design even at Dirt-loaded operating medium ensures high reliability and reliability.

The piston rod (6) opposite end face of the annular piston (12) is inventively provided with a ring land (15) on which a Rollfaltbelag (16) is arranged, which by means of clamping elements (17) against the pump housing (1) clamped clamping cover ( 18) is attached. This Rollfaltbelag (16) ensures a simple and reliable sealing of the annular piston (12) relative to the annular groove (10).

It is furthermore essential to the invention that one or more pressure connection bores (20) for the pressure actuation of the valve slide (4) is / are arranged in the pump housing (1) and open into a pressure connection piece (19) arranged on the pump housing (1).

It is characteristic, on the one hand, that the pressure connection bore (s) (20) on the compression spring side of the annular piston (12) opens into the annular chamber (32) formed by the annular groove (10) and annular piston (12). Thus, a defined displacement of the valve spool (4), and thus an active control of the coolant flow rate can be brought about by means of a pressure on the connecting piece (19), defined variable negative pressure. In conjunction with the invention according to the invention between the pump housing (1) and the annular piston (12) arranged compression springs (14), a further functioning of the coolant pump according to the invention (fail-safe) is guaranteed even in case of failure of the scheme.

According to the invention in this design in the clamping cover (18), in the work area of the roller folding (16), with the outside area communicating pressure equalization holes (21) are arranged. About these pressure compensation holes (21) is in displacement of the annular piston (12) the pressure equalization in the sealing chamber (26) between the clamping cover (18) and on the annular piston (12) arranged Rollfaltbelag (16).

On the other hand, it is also characteristic that the pressure connection bore (20) on the annular piston (12) arranged Rollfaltbelages (16) in the clamping cover (18) and on the annular piston (12) arranged Rollfaltbelag (16) formed sealing chamber (26) opens , In this design of the solution according to the invention, a defined displacement of the valve spool (4), and thus an active control of the coolant flow rate can be brought about by means of a pressure connection piece (19) applied, defined variable pneumatic or hydraulic overpressure. In conjunction with the invention according to the invention between the pump housing (1) and the annular piston (12) angeordenet compression springs (14), a further functioning of the coolant pump according to the invention (fail-safe) is guaranteed even in this design, even in case of failure.

Essential to the invention in this design is also that the valve spool side of the annular piston (12) in the region of the annular groove (10) in the pump housing (1) with the outside area in communication pressure equalization holes (21) are arranged. By means of these pressure compensation bores (21), pressure compensation in the annular chamber (32) between the annular groove (10) and the annular piston (12) is ensured when the annular piston (12) is displaced.

According to the invention further, that on the piston rod side outer edge (22) of the valve slide (4) an elastomeric bypass seal (23) is arranged, which can not contribute to the jamming of the valve spool during the spool stroke and in the closed position of the valve spool (4) the annular gap (25 ) between the pump housing (1) and the valve spool (4)

At the same time lies in this closed position (the end position in the position of the valve slide "CLOSED"), the valve spool (4) on a sealing surface (24) of the pump housing (1), so that even the smallest leaks in the position of the valve slide "CLOSED" are prevented.

The inventive arrangement ensures a "zero leakage" and thus optimum heating of the engine at high pump efficiency. By means of the arrangement according to the invention, moreover, after the engine has been heated, the engine temperature in continuous operation can be influenced so accurately that the pollutant emission, the friction losses as well as the fuel consumption are significantly reduced in the entire operating range of the engine.

Further details and features of the invention will become apparent from the dependent claims and the following description of the solution according to the invention in conjunction with the drawings of the embodiments.

Figur 1 :

eine erfindungsgemäße, regelbare Kühlmittelpumpe zur Unterdruckregelung in der Seitenansicht im Schnitt mit der Stellung des Ventilschiebers in seiner hinteren Endlage ("OFFEN");

Figur 2 :

die erfindungsgemäße, regelbare Kühlmittelpumpe zur Unterdruckregelung gemäß Figur 1, in der Seitenansicht in einem weiteren Schnitt mit der Stellung des Ventilschiebers in seiner hinteren Endlage ("OFFEN");

Figur 3 :

die erfindungsgemäße, regelbare Kühlmittelpumpe zur Unterdruckregelung in der Seitenansicht, im Schnitt analog Figur 1, jedoch mit der Stellung des Ventilschiebers in seiner vorderen Endlage ("GESCHLOSSEN");

Figur 4 :

eine erfindungsgemäße, regelbare Kühlmittelpumpe nun zur Überdruckregelung in der Seitenansicht im Schnitt mit der Stellung des Ventilschiebers in seiner hinteren Endlage ("OFFEN").

It shows:

FIG. 1:

an inventive, controllable coolant pump for negative pressure control in the side view in section with the position of the valve spool in its rear end position ("OPEN");

FIG. 2:

the inventive, controllable coolant pump for vacuum control according to FIG. 1 in the side view in a further section with the position of the valve spool in its rear end position ("OPEN");

FIG. 3:

the inventive, controllable coolant pump for vacuum control in the side view, in section analog FIG. 1 but with the position of the valve spool in its forward end position ("CLOSED");

FIG. 4:

an inventive, controllable coolant pump now for pressure control in the side view in section with the position of the valve spool in its rear end position ("OPEN").

In the FIG. 1 is one of the possible designs of the variable coolant pump according to the invention in section, shown in side view, with the position of the valve spool in its rear end position ("OPEN").

This design can be used in conjunction with a vacuum control.

In a pump housing 1, a driven shaft 2 is mounted in a pump bearing 27. On the free, flow-side ends of the shaft 2 is rotatably an impeller 3 is arranged. Adjacent to this impeller 3, a pressure-actuated annular valve spool 4 is displaceably arranged in the pump housing 1 with an outer cylinder 5 which covers the outflow region of the impeller 3 in variable manner. At the valve spool 4 a plurality of piston rods 6 are arranged. In the pump housing 1 are distributed in parallel to the shaft 2 uniformly over the circumference of the valve slide 4, assigned to the valve slide 4 arranged piston rods 6, a plurality of holes 7 introduced at the valve slide end are located in the pump housing 1 seal receivers 8 in which rod seals 9 are arranged at the opposite end of the holes 7 in the pump housing 1, an annular groove 10 is arranged which connects the holes 7 with each other. In the holes 7 piston guides 11 are arranged in which the arranged on the valve spool 4 piston rods 6 are mounted axially displaceable.

These arranged in the piston guides 11 piston rods 6 are connected to each other with their ringnutseitigen ends by means of an annular piston 12.

This annular piston 12 is slidably mounted in the annular groove 10. Between the holes 7 are distributed ringnutseitig in the pump housing 1 evenly over the circumference of the annular piston 12, spring chambers 13 are introduced in which against the annular piston 12 braced compression springs 14 are arranged.

The inventive arrangement of an annular, arranged on piston rods 6 and guided in sealed piston guides 11 in the pump housing 1, and operable via an annular piston 12 valve slide 4 represents a very compact, simple and robust design is the even in loaded with dirty cargo operating medium high reliability and reliability guaranteed.

The piston rod 6 opposite end face of the annular piston 12 is provided according to the invention with a ring land 15 on which a Rollfaltbelag 16 is arranged, which is fastened by means of a clamped with clamping elements 17 against the pump housing 1 clamp cover 18. This Rollfaltbelag 16 ensures a simple and reliable sealing of the annular piston 12 relative to the annular groove 10th

At the piston rod-side outer edge 22 of the valve slide 4, an elastomeric bypass seal 23 is arranged which can not contribute to the jamming of the valve slide during the slide stroke.

The FIG. 2 now shows the inventive, controllable coolant pump FIG. 1 to the negative pressure control in the side view, in another sectional view with the position of the valve spool turn in its rear end position ("OPEN").

In this design, a pressure connection piece 19 is arranged according to the invention on the pump housing 1 with a pressure connection bore 20 for the pressure actuation of the valve slide 4. The Pressure port 20 opens pressure spring side of the annular piston 12 in the annular groove 10. As a result, by means of a voltage applied to the pressure port 19, defined variable negative pressure a defined displacement of the valve spool 4, and thus an active control of the coolant flow are brought about. In conjunction with the in the FIG. 1 shown, according to the invention between the pump housing 1 and the annular piston 12 arranged compression springs 14 is a further functioning of the coolant pump according to the invention (fail-safe) guaranteed by the forced at the spring end position slider position "OPEN" even in case of failure of the vacuum control.

According to the invention, in the clamping lid 18, in the working area of the roller folding covering 16, pressure compensating bores 21 which are in communication with the outside area are arranged. About this pressure equalization holes 21 12 of the pressure compensation in the seal chamber 26 between the clamping cover 18 and the roller 16 is ensured upon displacement of the annular piston.

In addition, in the pump housing 1, a leakage bore 31 is arranged on the impeller side of the bearing seat, which connects a leakage access 30, which is arranged in the pump housing 1 at the front side of the pump bearing 27, to the outside area.

The FIG. 3 now shows the inventive, controllable coolant pump for vacuum control in the side view, in section analog FIG. 1 , but with the position of the valve spool in its front end position ("CLOSED").

In this closed position of the valve slide 4, the valve slide 4 is located on a sealing surface 24 of the pump housing 1 and closes simultaneously with the arranged on the piston rod side outer edge 22 of the valve spool 4 elastomer bypass seal 23, the annular gap 25 between the pump housing 1 and the valve spool 4, so that itself smallest leaks in the position of the valve slide "CLOSED" can be prevented.

By means of this arrangement according to the invention a "zero leakage" and thus optimum heating of the engine are ensured with high pump efficiency, whereby the motor temperature in continuous operation can be influenced so accurately by means of the arrangement according to the invention after the heating of the engine that both in the entire working range of the engine the pollutant emission as well as the friction losses and fuel consumption are significantly reduced.

Impeller side of the bearing seat with this design in the pump housing 1, a vent hole 28 is arranged which connects a pump housing 1 in the front end of the pump bearing 27 arranged vent inlet 29 to the outside.

Another design of the controllable coolant pump according to the invention is in the FIG. 4 in the side view, in section, with the position of the valve spool in its rear end position "OPEN" shown.

This design can be used in conjunction with a hydraulic or pneumatic overpressure control.

Also in this design a pressure connection piece 19 is arranged according to the invention on the pump housing 1. However, the pressure connection bore 20 now opens the clamping lid side of the arranged on the annular piston 12 Rollfaltbelages 16 in the sealing cover 26 formed by the clamping cover 18 and arranged on the annular piston 12 Roll fold 16.

In this design of the solution according to the invention, a defined displacement of the valve spool 4, and thus an active control of the coolant flow rate can now be performed by means of a voltage applied to the pressure port 19, defined variable pneumatic or hydraulic overpressure.

In conjunction with the, in the FIG. 1 shown, according to the invention arranged between the pump housing 1 and the annular piston 12 compression springs 14 is also in this design, even in case of failure of the scheme, a Continue functioning of the coolant pump according to the invention (fail-safe) guaranteed.

According to the invention are in this design valve spool side of the annular piston 12 in the region of the annular groove 10 in the pump housing 1 with the outside area communicating pressure equalization holes 21 arranged. About this pressure compensation holes 21, the pressure equalization in the annular chamber 32 between the annular groove 10 and the annular piston 12 is ensured upon displacement of the annular piston 1.

REFERENCE SYMBOL

1

pump housing

2

wave

3

impeller

4

valve slide

5

outer cylinder

6

piston rods

7

drilling

8th

poetry recordings

9

rod seals

10

ring groove

11

piston guides

12

annular piston

13

spring chambers

14

compression spring

15

ring land

16

Rollfaltbelag

17

clamping elements

18

terminal cover

19

Pressure connection piece

20

Pressure connection bore

21

Pressure compensating bore

22

outer edge

23

Elastomer bypass seal

24

sealing surface

25

annular gap

26

seal chamber

27

pump bearings

28

vent hole

29

vent inlet

30

leakage access

31

leakage hole

32

annular chamber

Claims (7)

1. Controllable coolant pump with a pump housing (1) a powered shaft (2) on bearings in a pump housing (1) a torque-resistant impeller located at one of the free, flow-sided ends of this shaft (2) and a pressure operated gate valve (4) with an external cylinder (5) variably covering the discharge area of the impeller (3), characterized by the fact,

   a) that the gate valve (4) is formed annularly and that several piston rods (6) are located at the gate valve (4), where several holes (7) are placed in the pump housing (1) parallel to the shaft (2) and distanced evenly around the circumference of the gate valve (4) and assigned with the piston rods (6) fitted at the gate valve (4), where gasket holders (8) are located in the pump housing (1) at the gate valve end where rod seals (9) are located, where an annular groove (10) is located in the pump housing (1) at the opposite end of the holes (7) which connects the holes with each other and where piston guideways (11) are located in the holes (7), where piston rods (6) are located at the gate valve (4) on bearings which can be slid axially, where the piston rods (6) located in the piston guideways (11) are connected together by an annular piston (12) with their ends on the annular groove side and that this annular piston (12) is on sliding bearings in the annular groove (10), where spring clips (13) are fitted evenly around the circumference of the annular piston (12) between the holes (7) in the pump housing (1), where pressure springs (14) are located under tension against the annular piston (12).

   b) that an annular support (15) on the top side of the annular piston opposite to the piston rods (8) where moving bellows are fastened to the clamping lid (10) of the pump housing (1) by using clamping elements (17).

   c) that one or several pressure connection holes (20) is/are located in the pump housing (1) for operating the gate valve (4) under pressure and which open out into a pressure connection socket (19) at the pump housing (1),

   d) that an elastomer bypass seal (23) is located at the outside edge (22) of the gate valve (4) which closes the annular gap (25) between the pump housing (1) and the gate valve (4) when the gate valve (4) is brought into contact in the closing position with a sealing surface (2) of the pump housing (1).
2. Controllable coolant pump in accordance with claim 1, characterized by the fact that the pressure connection holes (20) open out on the pressure side of the annular piston (12) into the annular compartment (32) formed by the annular groove (10) and the annular piston (12).
3. Controllable coolant pump in accordance with claim 1, characterized by the fact that the pressure connection holes (20) of the moving bellows (16) located on the clamping side at the annular piston (12) end in the sealing compartment (26) formed by the clamping lid (18) and moving bellows located at the annular piston (12).
4. Controllable coolant pump in accordance with claim 1, characterized by the fact that a ventilation hole (28) is located in the pump housing (1) on the pump impeller side of the bearing seating which connects a venting intake (29) located in the pump housing (1) on the front side of the pump bearing (27) with the outside area.
5. Controllable coolant pump in accordance with claim 1, characterized by the fact that a leakage hole (31) is located in the pump housing (1) on the pump impeller side of the bearing seating which connects a leakage intake (30) located in the pump housing (1) on the front side of the pump bearing (27) with the outside area.
6. Controllable coolant pump in accordance with claim 2, characterized by the fact that pressure equalization holes (21) are located in the clamping lid (18) in the working area of the moving bellows (16) to connect with the outside area.
7. Controllable coolant pump in accordance with claim 3, characterized by the fact that pressure equalization holes (21) are located in the pump housing (1) on the gate valve side of the working area of the annular piston (12) in the area of the annular groove (10) to connect with the outside area.

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