U.S. patent application number 14/359497 was filed with the patent office on 2014-10-16 for controllable coolant pump with an electro-hydraulic baffle plate adjustment.
This patent application is currently assigned to Schaeffler Technologies GmbH & Co. KG. The applicant listed for this patent is Eduard Golovatai-Schmidt, Markus Popp. Invention is credited to Eduard Golovatai-Schmidt, Markus Popp.
Application Number | 20140308115 14/359497 |
Document ID | / |
Family ID | 46639518 |
Filed Date | 2014-10-16 |
United States Patent
Application |
20140308115 |
Kind Code |
A1 |
Popp; Markus ; et
al. |
October 16, 2014 |
CONTROLLABLE COOLANT PUMP WITH AN ELECTRO-HYDRAULIC BAFFLE PLATE
ADJUSTMENT
Abstract
A controllable coolant pump of a cooling circuit for an internal
combustion engine, having a pump housing, in which a pump shaft
with associated impeller is rotatably arranged. The impeller
conveys a coolant as a volume flow via an intake connection in a
pressure or spiral channel of the coolant pump. The volume flow can
be influenced by a baffle plate which encloses the outside of the
impeller, the push rod of the baffle plate being guided in the pump
shaft. In connection with an actuator the baffle plate can be
continuously adjusted between two limit positions against the force
of a spring. A control element, which has an electro-hydraulic
action and which is integrated into the pump shaft, serves as an
actuator, wherein the pressurized coolant in the coolant pump is
provided as a hydraulic fluid.
Inventors: |
Popp; Markus; (Bamberg,
DE) ; Golovatai-Schmidt; Eduard; (Hemhofen,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Popp; Markus
Golovatai-Schmidt; Eduard |
Bamberg
Hemhofen |
|
DE
DE |
|
|
Assignee: |
Schaeffler Technologies GmbH &
Co. KG
Herzogenaurach
DE
|
Family ID: |
46639518 |
Appl. No.: |
14/359497 |
Filed: |
August 9, 2012 |
PCT Filed: |
August 9, 2012 |
PCT NO: |
PCT/EP2012/065576 |
371 Date: |
May 20, 2014 |
Current U.S.
Class: |
415/148 |
Current CPC
Class: |
F05D 2270/64 20130101;
F01P 5/12 20130101; F04D 15/0038 20130101; F04D 27/002 20130101;
F01P 7/164 20130101; F04D 13/12 20130101 |
Class at
Publication: |
415/148 |
International
Class: |
F04D 27/00 20060101
F04D027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 23, 2011 |
DE |
10 2011 086 934.4 |
Claims
1-9. (canceled)
10. A controllable cooling pump of a cooling circuit of an internal
combustion engine, comprising: a pump housing; a rotatably
supported pump shaft connected to an impeller driven by a traction
mechanism drive via an associated drive pulley, the impeller
conveying a coolant as a volume flow into a pressure or spiral
channel of the coolant pump via an intake connection; a baffle
plate capable of influencing the volume flow, the baffle plate
encompassing the impeller on the outside and a push rod associated
with the baffle plate being guided in the pump shaft, and the
baffle plate being continuously adjustable between two end
positions against the force of a spring in connection with an
actuator; the actuator being an electro-hydraulically operating
final control element integrated into the pump shaft and provided
for positioning the baffle plate, with the aid of which a working
chamber or a pressure chamber is filled with pressurized coolant of
the coolant pump as hydraulic fluid.
11. The coolant pump as recited in claim 10 wherein the actuator
has a solenoid switch, the actuator positioned in a stationary
manner, the solenoid switch acting upon a pump piston guided
directly or indirectly in a longitudinal bore of the pump shaft
designed as a hollow shaft, the pump piston together with the push
rod or a pressure piston assigned to the push rod delimiting the
working chamber of the pump shaft, which is filled with hydraulic
fluid.
12. The coolant pump as recited in claim 11 wherein the solenoid
switch engages with an end-side receptacle of the pump shaft, and
its centric switching axis interacts with the pump piston.
13. The coolant pump as recited in claim 10 wherein the hydraulic
fluid flows into the working chamber of the pump shaft via an inlet
as a function of a position of a pump piston.
14. The coolant pump as recited in claim 10 wherein the hydraulic
fluid flows into the working chamber of the pump shaft via a
one-way valve integrated into the inlet in the event of a pressure
difference or a pressure gradient.
15. The coolant pump as recited in claim 11 further comprising a
one-way valve allowing a pressure medium to flow in the direction
of the pressure piston inserted into the end of the longitudinal
bore of the pump shaft on the end facing away from the solenoid
switch.
16. The coolant pump as recited in claim 10 wherein a pressure
piston connected to the baffle plate via a push rod is guided in a
stepped bore of the pump shaft, the push rod being movable in a
positionally fixed guide bush of the pump shaft, a spring being
inserted between the pressure piston and the guide bush.
17. The coolant pump as recited in claim 10 further comprising a
cartridge or guide sleeve pressed into the longitudinal bore of the
pump shaft, which is designed to accommodate a pump piston, a
one-way valve as well as a spring inserted between the pump piston
and the one-way valve.
18. The coolant pump as recited in claim 10 wherein an actuation of
the actuator is controlled as a function of at least one operating
parameter of an internal combustion engine.
Description
[0001] The present invention relates to a controllable coolant pump
of a cooling circuit of an internal combustion engine. A pump
shaft, which includes an impeller and is preferably driven by a
traction mechanism drive via an associated drive pulley, is
rotatably supported in the pump housing of the coolant pump. The
impeller conveys a coolant as a volume flow into a pressure or
spiral channel of the coolant pump via an intake connection. The
volume flow may be influenced by a baffle plate which surrounds the
impeller on the outside and whose associated push rod is guided in
the pump shaft. In connection with an actuator, the baffle plate
may be continuously adjusted between two end positions against the
force of a spring means.
BACKGROUND
[0002] For the purpose of cooling fluid-cooled, in particular
water-cooled, internal combustion engines, a coolant or a cooling
medium is pumped through cooling channels of the crankcase and the
cylinder head of the internal combustion engine with the aid of a
coolant pump in a closed circuit, and the heated cooling medium is
subsequently recooled in an air-water heat exchanger. To support
the circulation of the coolant, a coolant pump is used which is
preferably driven directly by the internal combustion engine. Due
to a direct coupling between the coolant pump and the crankshaft, a
dependency of the pump rotational speed on the rotational speed of
the internal combustion engine sets in. Consequently, the coolant
circulates during a cold start of the internal combustion engine,
thereby delaying a desired fast heating of the internal combustion
engine. To optimize the operation of internal combustion engines,
the fastest possible reaching of the operating temperature after
the cold start is strived for. This makes it possible to reduce
friction losses and fuel consumption and, at the same time, lower
emission values. To achieve this effect, controllable coolant pumps
are used whose delivered volume flow may be adapted to the cooling
demand of the internal combustion engine. After a cold start, a
zero delivery of the coolant pump is strived for, after which the
volume flow destined for cooling the internal combustion engine
increases continuously as a function of the temperature level which
sets in. In a test series for optimizing the fuel consumption of
internal combustion engines, it was possible to reduce fuel
consumption by .gtoreq.3% by consequently implementing the
aforementioned measures.
[0003] A controllable coolant pump for a cooling circuit of an
internal combustion engine, which is driven by a traction mechanism
drive, is known from DE 10 2008 046 424 A1. To influence the volume
flow, the impeller is assigned an axially movable idler pulley,
which is axially movable with the aid of a push rod placed within
the hollow shaft of the impeller in connection with a final control
element. The final control element includes an armature connected
to the push rod, which is axially movable in a targeted manner via
a proportional solenoid. The electrically actuatable final control
element, or the actuator, is located on the front side upstream
from the drive belt pulley of the coolant pump. DE 199 01 123 A1
describes another controlled coolant pump. To influence the volume
flow, the impeller is assigned an outer, overlapping sliding
element whose position may be changed by twisting a thread-like
guide.
[0004] According to DE 10 2005 062 200 A1, the controlled coolant
pump includes a shaft, which is supported and driven in the pump
housing and has an associated impeller and a pneumatically or
hydraulically adjustable valve slide, which variably covers an
outflow area of the impeller. Multiple piston rods, which run in
parallel to the pump shaft in the pump housing and are guided in
annular grooves or bores and are sealed with the aid of rod seals
in the pump housing, are situated on the valve slide, distributed
over its circumference. The piston rods are operatively connected
on the annular groove side to an annular piston which is inserted
into a pressure chamber. The annual piston acted upon by pressure
springs and the valve slider connected thereto are moved by
applying pressure to the pressure chamber. A controllable coolant
pump is known from DE 10 2005 004 315 A1, in which a volume flow is
variable by a valve slide which surrounds the impeller and is
movable on the pump shaft. The valve slide may be actuated with the
aid of a solenoid armature which is acted upon by a solenoid coil
and is movable on the pump shaft. The entire electrical adjusting
device of the valve slide or the baffle plate, which surrounds the
pump shaft, is situated within the pump housing between the
impeller and a drive belt pulley of the coolant pump.
SUMMARY OF THE INVENTION
[0005] It is an object of the present invention to provide an
installation space-optimized, robust device for a controllable
coolant pump for adjusting the baffle plate to implement an
effective control of the volume flow of the coolant pump.
[0006] The structure of the controllable coolant pump according to
the present invention includes an electro-hydraulically operating
final control element as an actuator, which is integrated into the
pump shaft and with the aid of which a precise positioning of the
baffle plate may be carried out to facilitate an active control of
the volume flow or the coolant delivery quantity. The pressurized
coolant of the coolant pump is provided as hydraulic fluid for the
actuator. Integrating the actuator within the pump shaft reduces
the required installation space for the coolant pump in both the
radial and axial directions. Compared to previously known
approaches, the present invention thus permits the implementation
of a compact, installation space-optimized coolant pump. With the
aid of the concept according to the present invention, it is
possible, on the one hand, to ensure a gradual heating of the
engine and, on the other hand, to influence the temperature of the
internal combustion engine during continuous operation after the
operating temperature has been reached. The friction losses and
harmful emissions, and consequently the fuel consumption, may thus
be significantly reduced within the entire operating range of the
internal combustion engine.
[0007] The actuator may be advantageously pulsed in such a way that
a rapid filling of a working chamber and/or pressure chamber with
hydraulic fluid sets in for the purpose of quickly achieving a
complete blocking of the volume flow to represent a zero delivery
of the coolant pump after starting a cooled internal combustion
engine. The volume flow which is triggered or influenced by the
actuator for acting upon the pressure piston is greater than a
hydraulic fluid leakage of the pressure chamber which sets in. The
compact, simple and robust structure of the actuator according to
the present invention may be advantageously manufactured and
installed using a minimum amount of manufacturing and assembly
work. Due to the protected installation location of the actuator
integrated into the pump shaft, the operational reliability of the
actuator, and consequently the reliability of the coolant pump, is
improved. An advantageously high efficiency sets in with the aid of
the compact actuator as well as a hydraulic system which uses the
pressurized coolant of the coolant pump as hydraulic fluid. The
approach according to the present invention is also designed in
such a way that a coolant pump may be exchanged for coolant pumps
presently being used, even in engines already manufactured
today.
[0008] According to a preferred structural configuration of the
present invention, the actuator includes a solenoid switch, which
is positioned in a stationary manner and which acts directly upon a
pump piston movable within the pump shaft. The solenoid switch of
the actuator is preferably fastened in a stationary manner on the
pump housing or a machine part assigned to the coolant pump, for
example a crankcase of the internal combustion engine. In the
installed position, the solenoid switch engages with clearance with
an end-side receptacle of the pump shaft and is simultaneously
supported on the pump piston via a centric switching axis. Together
with the push rod or a pressure piston assigned to the push rod,
the pump piston delimits the working chamber within the pump shaft,
which is filled with hydraulic fluid and is designed as a cylinder.
An axial movement triggered by the solenoid switch, a lift of the
pump piston, is thus transmitted directly to the pressure piston,
thereby triggering a synchronous adjustment of the baffle
plate.
[0009] The structural configuration of the actuator hydraulics
provides that the pressurized pressure medium flows, for example,
out of the pressure or spiral channel of the coolant pump into the
working chamber of the pump shaft via an inlet as a function of a
position of the pump piston or as a function of pressure conditions
which set it. A first variant according to the present invention
provides that, in the de-energized state of the actuator, a pump
piston position sets in which corresponds to an end position of the
baffle plate in which a larger volume flow of the coolant pump sets
in, which fills the working chamber via the inlet without
hindrance. Upon actuation, i.e., energizing of the actuator, the
inlet is closed by the lift of the pump piston associated
therewith, which causes a pressure buildup in the working chamber
to set in. An alternative configuration includes a one-way or check
valve integrated into the inlet, which opens when a pressure
difference or pressure gradient sets in. This state sets in upon a
suction lift of the pump piston or if the solenoid switch of the
actuator is de-energized, combined with a pressure gradient, which
ensures a flow of pressure medium from the pressure or spiral
channel into the working chamber of the pump shaft.
[0010] According to the concept according to the present invention,
a one-way or check valve can be is-inserted into the end of the
longitudinal bore hole forming the working chamber of the hydraulic
system on the end facing away from the solenoid switch. The valve
limits the pressure piston and the baffle plate connected thereto
exclusively to a pressure medium flow, with the aid of which the
baffle plate is adjusted in the direction of a closed impeller or a
closed coolant pump. Ball valves are preferably suitable as one-way
or check valves in the inlet and the working chamber of the coolant
pump.
[0011] The structural configuration of the present invention
furthermore may include includes a pressure piston having a
cup-like design, which is connected to the baffle plate via the
push rod and is guided in a centric stepped bore of the pump shaft.
The push rod is axially movably guided in a receptacle or bore of a
fixed-position guide bush of the pump shaft, a pressure spring
being preferably inserted between the pressure piston and the guide
bush as a spring means. To limit hydraulic fluid leaks, the
pressure piston may be sealed against a stepped bore of the pump
shaft.
[0012] Designing individual components of the actuator as a unit
which may be preassembled suggests itself as a measure for
simplifying assembly complexity. A cartridge or guide sleeve, which
is designed to accommodate the pump piston, the one-way valve as
well as a spring means inserted between the pump piston and the
one-way valve and destined to act upon the pump piston in the
direction of the solenoid switch, is advantageously suitable for
this purpose. The preassembled structural unit may be subsequently
inserted into the longitudinal bore of the pump shaft in a
form-fitted and/or force-fitted manner.
[0013] According to the present invention, the switching or
activation of the actuator may furthermore be combined with a
control function for adjusting the baffle plate. Detecting at least
one operating parameter of the internal combustion engine, in
particular the coolant and/or lubricating oil temperature of the
internal combustion engine, as a control variable and comparing it
with a reference or guide temperature to purposefully carry out an
adjustment of the baffle plate in the event of deviations, is
preferably an option. A preferred control configuration includes a
sensor system for detecting the temperature as well as a control
unit which carries out the temperature compensation. In the event
of a deviation, the solenoid switch of the actuator is activated by
the control unit for the purpose of targeted adjustment of the
baffle plate to influence the volume flow of the coolant pump and
thus the operating temperature of the internal combustion
engine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Additional features of the present invention are derived
from the following description, in which two exemplary embodiments
of the present invention are illustrated.
[0015] FIG. 1 shows a first exemplary embodiment of a coolant pump
designed according to the present invention, having an actuator
integrated into the pump shaft;
[0016] FIG. 2 shows a second exemplary embodiment of a coolant pump
designed according to the present invention, having a baffle plate
position in the de-energized state of the actuator;
[0017] FIG. 3 shows the coolant pump according to FIG. 2, having a
baffle plate position that sets in when the actuator is in the
de-energized state.
DETAILED DESCRIPTION
[0018] FIG. 1 shows a sectional view of a coolant pump 1, which may
be preferably used for a coolant circuit of an internal combustion
engine. A pump shaft 3, which is designed as a hollow shaft and is
rotatably supported on two bearings 4, 5 designed, in particular,
as roller bearings, is introduced into a pump housing 2 of coolant
pump 1. First bearing 4 is inserted into a bore 6 of pump housing
2, and second bearing 5 is inserted between a shoulder of pump
housing 2 and an axial receptacle of a belt pulley 7 rotatably
fixed on pump shaft 3. Coolant pump 1 is driven by a traction
mechanism drive 100 (shown schematically), a traction mechanism, a
belt or a chain connecting drive pulley 7 to another drive pulley.
An impeller 8, which is situated opposite drive pulley 7 on pump
shaft 3, is assigned to an suction chamber 9, with the aid of which
the coolant is radially conveyed as a volume flow into an annular
or spiral chamber 102 (shown schematically) of pump housing 2 in
the operating state of coolant pump 1. Suction chamber 9 is
delimited by a cover disk 10, which simultaneously forms a
transition to the spiral channel. To influence the volume flow of
coolant pump 1, impeller 8 is assigned an axially movable baffle
plate 11, which is supported directly on impeller 8 in a first end
position, as shown in FIG. 1. A maximum volume flow of coolant pump
1 may be implemented in this baffle plate position, which
corresponds to the largest opening. A zero delivery of coolant pump
1 sets in as soon as baffle plate 11 is supported on cover disk 10
in the second end position. Baffle plate 11 is rotatably rigidly
connected to a push rod 12, which is linearly movable and
positionable between the end positions or arbitrary intermediate
positions, as illustrated by a double arrow. For this purpose, push
rod 12 is guided in a bore 13 of a guide bush 14, which is pressed
into a stepped bore 15 of pump shaft 3. Facing away from baffle
plate 11, push rod 12 furthermore includes a pressure piston 16. An
electro-hydraulically operating final control element, which is
integrated into pump shaft 3, is used as actuator 17 to set or
adjust baffle plate 11, the pressurized coolant of coolant pump 1
being provided as hydraulic fluid.
[0019] For this purpose, a solenoid switch 18 of actuator 17, which
is fastened in a stationary manner to a machine part 20, for
example the housing of the internal combustion engine, engages with
clearance with an end-side receptacle 19 of pump shaft 3. A centric
switching axis 21 of solenoid switch 18 is supported directly on a
pump piston 22, which is movably guided in a cartridge 23, which is
pressed into longitudinal bore 24 of pump shaft 3. Cartridge 23,
which is designed as a cylindrical guide sleeve and extends over
entire longitudinal bore 24, forms a working chamber 27 which is
filled with hydraulic fluid and is axially delimited by pump piston
22 and a one-way valve 25, between which a spring means 26 applying
an expanding force is inserted. In the baffle plate position
illustrated in FIG. 1, a pressure level sets in in working chamber
27, which nearly corresponds to the pressure which sets in in the
annular or spiral channel of pump housing 2 in the operating state.
For this purpose, the hydraulic fluid may flow into the working
chamber via an inlet 28 having an associated one-way valve 29. An
actuation of solenoid switch 18 in the direction of the arrow
causes a pressure rise in working chamber 27 as soon as one-way
valve 29 is closed. At the same time, the hydraulic fluid flows
through one-way valve 25 and acts upon a pressure chamber 31 which
is axially delimited by pressure piston 16 and one-way valve 25,
whereby push rod 12, which is connected to pressure piston 16,
moves together with baffle plate 11 in the direction of cover disk
10. The actuating force of actuator 17 or solenoid switch 18
exceeds the spring force of spring means 26 acting directly upon
pump piston 22 as well as the spring force of a second spring means
30 inserted between pressure piston 16 and guide bush 14. In the
de-energized state of solenoid switch 18, spring means 26 causes
pump piston 22 to automatically return to the position
corresponding to FIG. 1. Baffle plate 11 initially remains in the
set position, since one-way valve 25 prevents the hydraulic fluid
from flowing back from pressure chamber 31.
[0020] Due to a hydraulic fluid leak, which sets in, in particular
between pressure piston 16 and stepped bore 15 of pump shaft 3,
supported by a spring force of spring means 30, baffle plate 11 is
pushed more slowly in the direction of pump housing 2 via pressure
piston 16 in the de-energized state of solenoid switch 18. Another
pump cycle begins as soon as solenoid switch 18 is energized again.
If solenoid switch 18 is energized in a pulsed manner, working
chamber 27 is pumped up continuously. Solenoid switch 18 of
actuator 17 and its pulsing are designed in such a way that a fast
filling of working chamber 27 and consequently of pressure chamber
31 with hydraulic fluid is ensured. When starting a cooled internal
combustion engine, an active contact of baffle plate 11 on cover
disk 10 may be ensured to achieve a complete blocking of the volume
flow, i.e., a zero delivery of coolant pump 1. The volume flow
triggered by solenoid switch 18 of actuator 17 for acting upon
pressure piston 16 is designed to be greater than a hydraulic fluid
leakage of pressure chamber 31 which sets in.
[0021] FIGS. 2 and 3 show a cutout of coolant pump 1 having an
alternatively designed, electro-hydraulically operating actuator
37. The following description relates to the distinguishing
features between the first variant according to FIG. 1 and the
second variant illustrated in FIGS. 2 and 3, the components or
areas corresponding to FIG. 1 being provided with the same
reference numerals.
[0022] According to FIGS. 2 and 3, inlet 38 does not include a
one-way valve in working chamber 47, so that hydraulic fluid is
able to flow directly into working chamber 47 via inlet 38,
depending on the position of pump piston 32. FIG. 2 shows pump
piston 32 in a position which blocks inlet 38, this position being
taken in the de-energized state of solenoid switch 18 of actuator
37. Deviating from FIG. 1, pump piston 32, spring means 26 and
one-way valve 45 are guided directly in longitudinal bore 34 of
pump shaft 33. As soon as inlet 38 is closed, at least a partial
quantity of the hydraulic fluid is displaced out of working chamber
47 and into pressure chamber 48 through opened one-way valve 45,
due to the actuation of pump piston 32, and pressure piston 36,
including push rod 42 and baffle plate 41, is consequently
displaced. To reduce leaks, pressure piston 36 is inserted into
stepped bore 35, forming a seal and, for this purpose, forms a
circumferential annular groove 39, into which a sealing ring 44 is
inserted. Opposite pressure chamber 51a spring means 40 is inserted
within stepped bore 35 of pump shaft 33 between guide bush 46,
which is positioned in a stationary manner and connected to a
carrier element 43, push rod 42 and pressure piston 36. A bore 50,
which is radially offset with respect to guide 49 for push rod 41,
is introduced into guide bush 46, via which a pressure compensation
takes place during the actuations of pressure piston 36. FIG. 3
shows the position of pump piston 32 as well as baffle plate 41 in
the de-energized state of solenoid switch 18 of actuator 37. Pump
piston 32 is in an end position which facilitates a flowing of
hydraulic fluid into working chamber 47 via inlet 38. At the same
time, baffle plate 41 is in a position whereby a maximum volume
flow of coolant pump 1 sets in.
LIST OF REFERENCE NUMERALS
[0023] 1 coolant pump [0024] 2 Pump housing [0025] 3 Pump shaft
[0026] 4 Bearing [0027] 5 Bearing [0028] 6 Bore [0029] 7 Drive
pulley [0030] 8 Impeller [0031] 9 Suction chamber [0032] 10 Cover
disk [0033] 11 Baffle plate [0034] 12 Push rod [0035] 13 Bore
[0036] 14 guide bush [0037] 15 Stepped bore [0038] 16 Pressure
piston [0039] 17 Actuator [0040] 18 Solenoid switch [0041] 19
Receptacle [0042] 20 Machine part [0043] 21 Switching axis [0044]
22 Pump piston [0045] 23 Cartridge [0046] 24 Longitudinal bore
[0047] 25 One-way valve [0048] 26 Spring means [0049] 27 Working
chamber [0050] 28 Inlet [0051] 29 One-way valve [0052] 30 Spring
means [0053] 31 Pressure chamber [0054] 32 Pump piston [0055] 33
Pump shaft [0056] 34 Longitudinal bore [0057] 35 Stepped bore
[0058] 36 Pressure piston [0059] 37 Actuator [0060] 38 Inlet [0061]
39 Annular groove [0062] 40 Spring means [0063] 41 Baffle plate
[0064] 42 Push rod [0065] 43 Carrier element [0066] 44 Sealing ring
[0067] 45 One-way valve [0068] 46 Guide bush [0069] 47 Working
chamber [0070] 48 Pressure chamber [0071] 49 Guide [0072] 50 Bore
[0073] 100 Traction mechanism drive [0074] 102 Pressure channel
* * * * *