U.S. patent application number 12/113592 was filed with the patent office on 2008-11-06 for cavitation-deterring energy-efficient fluid pump system and method of operation.
This patent application is currently assigned to METALDYNE COMPANY LLC.. Invention is credited to David L. Killion.
Application Number | 20080273992 12/113592 |
Document ID | / |
Family ID | 39537504 |
Filed Date | 2008-11-06 |
United States Patent
Application |
20080273992 |
Kind Code |
A1 |
Killion; David L. |
November 6, 2008 |
CAVITATION-DETERRING ENERGY-EFFICIENT FLUID PUMP SYSTEM AND METHOD
OF OPERATION
Abstract
A variable nozzle area jet pump is provided having a
nozzle-sealing member resiliently urged to form a sealing closure.
The sealing member is part of a normally non-passing pressure
control valve that recirculates excess fluid back to the inlet of a
positive displacement fluid pump. The fluid is recirculated with
elevated pressure after a threshold fluid pressure is exceeded. The
disclosed system provides for energy conservation and pump
cavitation speed increase. The system may be integrated with an
engine balance shaft module so as to provide low cost robustness to
low speed gear noise emissions by application of the oil pump's
drive torque to at lease one gearset.
Inventors: |
Killion; David L.;
(Clarkston, MI) |
Correspondence
Address: |
CANTOR COLBURN, LLP
20 Church Street, 22nd Floor
Hartford
CT
06103
US
|
Assignee: |
METALDYNE COMPANY LLC.
Plymouth
MI
|
Family ID: |
39537504 |
Appl. No.: |
12/113592 |
Filed: |
May 1, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60927484 |
May 3, 2007 |
|
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|
Current U.S.
Class: |
417/185 ;
123/196R; 123/90.33; 417/186; 417/189; 417/190 |
Current CPC
Class: |
F04B 23/12 20130101;
F04C 15/062 20130101; F04F 5/461 20130101; F04C 11/005 20130101;
F04F 5/54 20130101 |
Class at
Publication: |
417/185 ;
417/186; 417/190; 417/189; 123/90.33; 123/196.R |
International
Class: |
F04F 5/44 20060101
F04F005/44; F04F 5/50 20060101 F04F005/50; F01M 1/02 20060101
F01M001/02 |
Claims
1. A pump system comprising: a first positive displacement pump
having an inlet passage and a discharge passage; and an adjustable
nozzle jet pump valve having: a supply chamber fluidly coupled to
said discharge passage, said supply chamber further having a port
with a seat surface; a movable valve member having a sealing
surface in sealing contact with said seat surface when in a first
position, and a body portion, said body portion further having a
first face sealingly positioned within said supply chamber, and an
opposing second face, said first face having a first surface area;
an urging member coupled to said second face; a suction chamber
fluidly coupled to said port; a throat passage fluidly coupled to
said suction chamber and said inlet passage wherein said port, said
suction chamber and said throat passage are arranged in a
continuous serial fluid connection to said inlet passage.
2. The pump system of claim 1 wherein said adjustable nozzle jet
pump valve includes an orifice fluidly coupled to said second
face.
3. The pump system of claim 2 wherein said orifice is vented to
atmospheric pressure.
4. The pump system of claim 2 wherein said venting to atmospheric
pressure is by means of fluid coupling with an oil reservoir
exposed to atmospheric pressure.
5. The pump system of claim 1 wherein said urging member is a
spring arranged to bias said movable valve member sealing surface
against said seat.
6. The pump system of claim 1 wherein said urging member is an
electromechanical actuator.
7. The pump system of claim 1 further comprising: an uptake passage
fluidly coupled to said suction chamber and to a fluid reservoir;
and, a one-way check valve fluidly coupled between a fluid
reservoir and said inlet passage.
8. The pump system of claim 1 wherein said throat passage comprises
an entry bell for smoothing the acceleration of flows entering said
throat passage, said entry bell having outside diameter larger than
an outside diameter circumscribing said throat passage.
9. The pump system of claim 1 wherein said adjustable nozzle jet
pump valve includes a diaphragm member coupled to said body
portion.
10. The pump system of claim 1 wherein said adjustable nozzle jet
pump valve includes a bellows member coupled to said body
portion.
11. The pump system of claim 1 further comprising: a fluid
reservoir fluidly coupled to said suction chamber; and, a second
positive displacement pump fluidly coupled between said fluid
reservoir and said discharge passage.
12. The pump system of claim 1 wherein said adjustable nozzle jet
pump valve further comprises a pilot chamber positioned between
said body member and said supply chamber.
13. A pump system for a variable consumptive load, said system
comprising: a first positive displacement pump, said pump having an
inlet passage and a discharge passage, wherein said discharge
passage is arranged to couple with said variable consumptive load;
a jet pump valve having a variable nozzle opening area fluidly
coupled between said discharge passage and said inlet passage, said
jet pump valve including means for changing the area of said
variable nozzle opening in direct response to changes in fluid
pressure in said discharge passage, said jet pump valve further
including an urging member arranged to bias a member to close said
variable nozzle opening; said jet pump valve further having a
suction chamber adjacent said variable nozzle opening and arranged
to receive fluid from said variable nozzle opening and from a fluid
reservoir; said jet pump valve further having a throat passage
coupled to said suction chamber, said throat passage being fluidly
coupled to receive fluid from said reservoir and from said variable
valve opening, and to transfer said received fluid to said inlet
passage.
14. The pump system of claim 13 wherein: said means for changing
the size of said variable nozzle opening comprises: a supply
chamber in direct fluid connection to said discharge line; and, a
valve body movable between a first position and a second position,
said valve body having a sealing member with a first cross
sectional area and a first face with a second surface, where in
said second surface's area is greater than said first cross
sectional area, and wherein said sealing member is in contact with
and closes said variable nozzle opening when said valve body is in
said first position.
15. The pump system of claim 14 further comprising a damping
chamber, wherein a portion of said valve body forms a portion of
one side of said damping chamber.
16. The pump system of claim 15 further comprising a damping
orifice fluidly coupled to said damping chamber.
17. The pump system of claim 16 wherein said damping orifice is
vented to atmospheric pressure by means of fluid coupling with an
oil reservoir exposed to atmospheric pressure.
18. The pump system of claim 13 further comprising: a fluid
reservoir fluidly coupled to said first positive displacement pump;
and, a second positive displacement pump fluidly coupled between to
said fluid reservoir and said discharge passage.
19. The pump system of claim 18 further comprising a bypass passage
fluidly coupled to said supply chamber when said valve body is in
said second position.
20. The pump system of claim 13 further comprising a one way check
valve fluidly coupled between said reservoir and said inlet passage
adjacent one end of said throat passage opposite said inlet
transition region.
21. The pump system of claim 20 wherein said valve is a ball and
seat type valve or a reed type valve.
22. The pump system of claim 20 wherein said valve includes a
member having a substantially cup-shaped cross-section, and a seat,
said cup shape having sides which slidingly engage a pilot member
for locating of a face area of said cup-shaped member in sealable
proximity to said seat.
23. The pump system of claim 13 wherein said urging member is a
compression spring.
24. The pump system of claim 13 wherein said urging member is an
electromechanical actuator.
25. The pump system of claim 14 further comprising a pilot pressure
chamber adjacent said first face, wherein said pilot pressure
chamber having a partition wall that inhibits flow from said supply
chamber to said pilot pressure chamber.
26. The pump system of claim 25 further comprising a seal arranged
between said supply chamber and said pilot pressure chamber.
27. The pump system of claim 13 wherein said throat passage further
includes an inlet transition region coupled to said suction
chamber.
28. The pump system of claim 13 wherein said means for changing the
area of said variable nozzle opening is in direct response to
changes in fluid pressure in said consumptive load.
29. The pump system of claim 13 further comprising an actuator
movable between a first position and a second position, said
actuator being coupled to said urging member, wherein said urging
member provides a first force when said actuator is in said first
position and a second force when said actuator is in said second
position.
30. A method of operating a pump system comprising: pressurizing a
fluid with a positive displacement pump; discharging said fluid
into a discharge passage; flowing a portion of said fluid from said
discharge passage directly into a valve supply chamber; applying
pressure to a valve body face; moving said valve body; opening a
port in said valve supply chamber; ejecting said fluid into a
suction chamber; and, increasing the fluid pressure at an inlet to
said displacement pump by injecting said fluid across a suction
chamber into a throat passage which also receives fluid from a
reservoir by means of said suction chamber.
31. The method of claim 30 further comprising the step of varying
the opening area of said port in direct response to changes in
pressure of said fluid in said outlet passage.
32. The method of claim 31 further comprising the steps of:
adducting fluid in said suction chamber towards said injected
fluid; flowing said adducted fluid and said injected fluid into a
throat passage; flowing said adducted and injected fluids to said
displacement pump inlet.
33. The method of claim 30 further comprising the step of biasing
said valve body towards said port.
34. The method of claim 33 wherein said step of moving said valve
body occurs if the pressure in said discharge passage increases
beyond a first threshold.
35. The method of claim 34 further comprising the step of opening a
one-way valve fluidly coupled to said inlet if pressure at said
inlet is less than a second threshold.
36. The method of claim 30 further comprising the step of powering
said positive displacement pump by driving connectivity with a
balance shaft for an internal combustion engine having at least one
piston and connecting rod assembly.
37. The method of claim 36 further comprising the step of
transferring said fluid to said internal combustion engine.
38. The method of claim 29 further comprising the steps of:
applying a force with an urging member to said valve body; and,
changing the magnitude of said force in response to a switching
event.
39. An internal combustion engine comprising: a balance shaft
assembly; a first positive displacement pump, said pump having an
inlet passage and a discharge passage, wherein said discharge
passage is arranged to fluidly couple with said balance shaft
assembly; a jet pump valve having a variable nozzle opening area
fluidly coupled between said discharge passage and said inlet
passage, said jet pump valve including means for changing the area
of said variable nozzle opening in direct response to changes in
fluid pressure in said discharge passage, said jet pump valve
further including an urging member arranged to bias a member to
close said variable nozzle opening; said jet pump valve further
having a suction chamber adjacent said variable nozzle opening and
arranged to receive fluid from said variable nozzle opening and a
fluid reservoir; and, said jet pump valve further having a throat
passage coupled to said suction chamber, said throat passage being
fluidly coupled to receive fluid from said reservoir and said
variable valve opening and transfer said received fluid to said
inlet passage.
40. The internal combustion engine of claim 39 wherein said means
for changing the area of said variable nozzle opening is in direct
response to changes in fluid pressure in said internal combustion
engine.
41. The internal combustion engine of claim 39 further comprising
an actuator movable between a first position and a second position,
said actuator being operably coupled to said urging member wherein
said urging member provides a first force when said actuator is in
said first position and a second force when said actuator is in
said second position.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims benefit of U.S. Provisional
Application Ser. No. 60/927,484 filed May 3, 2007, and entitled
"Energy Efficient Fluid Pump System." which is incorporated by
reference herein in its entirety.
FIELD OF ART
[0002] The present invention relates generally to a fluid pump
system for an engine or other system, and more particularly, to the
provision of low cost increases in the cavitation speeds of
positive displacement fluid pumps, concurrent with useful power
consumption reductions over a wide range of operational speeds, in
applications offering limited packaging space.
BACKGROUND
[0003] The use of an adjustable nozzle area jet pump having
normally non-passing pressure control valve functionality to
conserve energy by delivering pressurized recirculation flow back
to the inlet of a positive displacement fluid pump under widely
varying load conditions is known in the art. The use of a positive
displacement pump to reduce the timing gear noise emissions of an
engine balance shaft module at low cost by applying the oil pump's
driving torque to minimize gear tooth separation is also known.
These types of engine balance shaft module applications typically
drive the pump at twice engine speed by means of a driving
connection with a twice engine speed balance shaft. This
arrangement is beneficial in terms of both pump volumetric
efficiency at low speeds and required pump packaging space claim.
However, such applications often represent significant challenge
when an operating speed range that is often greater than an order
of magnitude in breadth is combined with a requirement for copious
low speed flow volume. This is due to increased-displacement pumps
generally suffering from reduced cavitation speeds, those where
pump filling becomes challenged for lack of sufficient inlet
passage pressure. This challenging combination is becoming
increasingly commonplace with marketplace demands for
ever-improving engine performance. These demands result in engine
applications having both oil flow resistance-lowering features such
as variable valve timing, and increased peak operating speeds.
[0004] Jet pump recirculation of unused flow volumes has proven to
be an effective means of both reducing power consumption and
increasing pump cavitation speeds in case of high speed
applications utilizing positive displacement pumps. The energy
efficiency benefits of jet pump recirculation are extendable into
the lower portions of an operating speed range by means of the
efficiency-broadening character of adjustable nozzle jet pumps.
Additionally, the elimination of the upstream-of-jet pump pressure
drop of a separate flow control valve, by integrating normally
non-passing pressure control valve functionality into an adjustable
nozzle jet pump offers the potential of improved recycling
efficiency. However, current art systems typically require a
differential control valve means, responsive to the difference
between the inlet pressure and the discharge pressure of the
positive displacement pump. This arrangement is much more costly
and space-consumptive than necessary to achieve the desired
functionality of optimized energy efficiencies and cavitation
speeds in fluid pump systems that for avoidance of cost,
complexity, or packaging space claim require positive displacement
pumps to function over a wide range of speeds. Other prior art
adjustable nozzle jet pumps having normally non-passing pressure
control valve functionality similarly define much more costly and
complex structures than are necessary for the purpose of achieving
the above-cited desired functionality.
[0005] Accordingly, while existing pump systems are adequate for
their intended purposes, there exists a need for a simpler, lower
cost, and less space claim-consumptive fluid pump system for
improving both cavitation speed and normal speed range power
consumption. There is further need for these improvements in
applications where in order to minimize cost, complexity, and/or
packaging spaceclaim, positive displacement pumps are required to
function over a wide range of speeds.
SUMMARY OF THE INVENTION
[0006] A pump system is provided having a positive displacement
pump. The positive displacement pump includes an inlet passage and
a discharge passage. The pump system further includes an adjustable
nozzle jet pump valve. The adjustable nozzle jet pump valve
includes a supply chamber fluidly coupled to the first positive
displacement pump discharge passage. The supply chamber includes a
port with a seat surface. A movable valve member having a sealing
surface and a body portion is arranged in the adjustable nozzle
jet. The sealing surface is arranged in sealing contact with the
seat surface when in a first position. The body portion has a first
face sealingly positioned within the supply chamber, and an
opposing second face. The first face has a first surface area. The
adjustable nozzle jet pump valve further includes an urging member,
a suction chamber and a throat passage. The urging member is
arranged and coupled to the second face. The suction chamber is
fluidly coupled to the port. The throat passage fluidly is coupled
to the suction chamber and the inlet passage. The port, the suction
chamber and the throat passage are arranged in a continuous serial
fluid connection to the inlet passage.
[0007] Another embodiment pump system for a variable consumptive
load is also provided. The pump system includes a first positive
displacement pump having an inlet passage and a discharge passage,
wherein the discharge passage is arranged to couple with the
variable consumptive load. A jet pump valve is provided having a
variable nozzle opening area directly fluidly coupled between the
discharge passage and the inlet passage. The jet pump valve also
includes means for changing the area of the variable nozzle opening
in direct response to changes in a fluid pressure such as that in
the discharge passage. The jet pump valve further includes an
urging member arranged to bias a member to close the variable
nozzle opening. The jet pump valve further also includes a suction
chamber adjacent the variable nozzle opening and arranged to
receive fluid from the variable nozzle opening and from a fluid
reservoir. A throat passage is provided in the jet pump valve and
is coupled to the suction chamber. The throat passage is further
fluidly coupled to receive fluid from the reservoir and from the
variable valve opening. The throat passage transfers the received
fluid to the inlet passage.
[0008] A method of operating a pump system is also provided. The
method includes pressurizing a fluid with a positive displacement
pump. The fluid is discharged into a discharge passage and a
portion of the fluid is flowed from the discharge passage into a
valve supply chamber. Pressure is applied to a valve body face. The
valve body is moved to open a port in the valve supply chamber.
Fluid is ejected into a suction chamber. Finally, the fluid
pressure is increased at an inlet to the displacement pump by
injecting the fluid across a suction chamber and into a throat
passage. The throat passage further receives fluid from a reservoir
by means of the suction chamber.
[0009] An internal combustion engine having a balance shaft
assembly is also provided. A first positive displacement pump
having an inlet and a discharge passage is arranged such that the
discharge passage is fluidly coupled with the balance shaft
assembly. A jet pump valve having a variable nozzle opening area is
provided where the variable nozzle opening is fluidly coupled
between the discharge and the inlet passage. The jet pump valve
includes means for changing the area of the variable nozzle opening
in direct response to changes in fluid pressure in the discharge
passage. The jet pump valve further includes an urging member
arranged to bias a member to close the variable nozzle opening. A
suction chamber is arranged in the jet pump valve adjacent the
variable nozzle opening to receive fluid from the variable nozzle
opening and a fluid reservoir. The jet pump valve further includes
a throat passage coupled to the suction chamber. The throat passage
is fluidly coupled to receive fluid from the reservoir and the
variable valve opening and transfer the received fluid to the inlet
passage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic illustration of an exemplary
embodiment cavitation-deterring energy-efficient pump system;
[0011] FIG. 2 is a schematic illustration of the pump system of
FIG. 1 with the nozzle sealing member having been moved, by system
pressure, for jet pump pressurization of the positive displacement
pump's inlet;
[0012] FIG. 3 is a schematic illustration of the pump system of
FIG. 1 having an alternate embodiment supplemental pump that adds
its flow volume to that of the energy efficient pumping system to
circumvent a "throat restriction at pre-boost operating conditions"
issue;
[0013] FIG. 4 is a schematic illustration of the pump system of
FIG. 3 with the nozzle sealing member at a "bypass threshold"
position;
[0014] FIG. 5 is a schematic illustration of the pump system of
FIG. 3 with the "full bypass" nozzle sealing member position;
[0015] FIG. 6 is a schematic illustration of the pump system of
FIG. 1 with an alternate embodiment arrangement of circumventing
the "throat restriction at pre-boost operating conditions"
issue;
[0016] FIG. 7 is a schematic illustration of the pump system of
FIG. 6 at a system pressure that has moved the nozzle sealing
member and initiated boost pressure, or reduction in vacuum
magnitude, in the throat-to-pump inlet passage or diffuser, wherein
the check valve ball is shown seated;
[0017] FIG. 8 is a schematic illustration of the pump system of
FIG. 1 having an alternate embodiment, a low cost, low mass, and
vibration-robust check valve in the throat-bypassing supply
passage;
[0018] FIG. 9 is a schematic illustration of the pump system of
FIG. 1 with another alternate embodiment check valve arrangement, a
so-called reed valve assembly check valve in the throat-bypassing
supply passage;
[0019] FIG. 10 is a schematic illustration of the pump system of
FIG. 1 with an alternate embodiment wherein a nozzle supply cavity
sealing partition isolates the sealingly mobile pressure area of
the nozzle sealing member for control of system pressure at a
location downstream of a flow resistance, by means of a separate
remote pilot pressure control passage;
[0020] FIG. 11 is a schematic illustration of the pump system of
FIG. 10 having a positive seal between the nozzle sealing member
and the nozzle supply cavity sealing partition;
[0021] FIG. 12 is a schematic illustration of the pump system
having an alternate embodiment electronic actuator as a control
device whereby system delivery pressure may be electronically
controlled in response to a signal;
[0022] FIG. 13 is a schematic illustration of a pump system with a
combination of remote pilot and electronic pressure controls,
whereby system pressure is passively managed to maintain threshold
downstream-of-resistance pressure targets, and may additionally be
actively managed;
[0023] FIG. 14 is a schematic illustration of the pump system
providing for direct movement of the nozzle sealing member by an
electronic pressure control;
[0024] FIG. 15 illustrates the pump system of FIG. 1 with a
leakage-proof nozzle sealing member;
[0025] FIG. 16 illustrates another alternate embodiment pump system
having an alternate embodiment leakage-proof nozzle sealing
member;
[0026] FIG. 17 illustrates a graphical comparison between the
empirical pressure curves of a conventional positive displacement
pump system and the exemplary embodiment, for the satisfaction of a
hypothetical high speed pressure target with the same positive
displacement pump;
[0027] FIG. 18 illustrates a graphical comparison between the drive
system power consumptions of the conventional positive displacement
pump system and the exemplary embodiment, including a percentage
difference curve; and,
[0028] FIG. 19 illustrates a schematic illustration of the pump
system of FIG. 1 coupled to a modular balance shaft assembly and
internal combustion engine.
DETAILED DESCRIPTION OF THE INVENTION
[0029] Adjustable nozzle jet pumps are known for substantially
extended efficiency range in comparison with fixed nozzle area jet
pumps. In the exemplary embodiment, a consistently high velocity of
nozzle exit flow enables an automatically-adjusted variable nozzle
area jet pump to provide this performance advantage more or less
continually in the case of variable operating conditions.
Substantial further efficiency range advantages are gained over
fixed area ratio jet pump-assisted positive displacement pumping
systems by means of the exemplary embodiment's low cost, compact
integration of normally non-passing pressure control valve
functionality with an adjustable nozzle-type jet pump.
[0030] The exemplary embodiment utilizes this simple normally
non-passing pressure-controlling adjustable nozzle jet pump valve
(hereafter referred to as a "Jet Pump Valve" or "JPV") to captively
recirculate unused flow volumes back to a positive displacement
pump's inlet with pressure boost (or reduction of vacuum) when the
operating system pressure exceeds a predetermined threshold. The
integration provided in the exemplary embodiment effectively
eliminates all of the flow energy losses customarily incurred with
a so-called "bypass valve," or "pressure-relief valve," hereafter
called a "PRV," upstream of the nozzle supply passage. The JPV's
"pressure relief" restriction itself is used as the means for
efficiently propelling the unused flow volumes to high velocity in
a useful direction. This elimination of a separate PRV thus
increases the energy available to accelerate nozzle flow to high
velocities and thereby enables peak efficiency to be achieved at
reduced cost in comparison with current art systems.
[0031] The elimination of a separate PRV provides, by means of the
consistently high energy of nozzle discharge flow, the
energy-saving benefit of pressure enhancement to the inlet passage
of the positive displacement pump to commence immediately upon the
achievement of the predetermined threshold pressure and the
associated onset of nozzle discharge flow. This greatly extends the
range of operating conditions wherein useful efficiency advantages
are provided, in comparison with fixed nozzle jet pump
recirculation systems.
[0032] Referring now to FIG. 1, the exemplary embodiment
cavitation-deterring energy-efficient fluid pump system 10 is
illustrated. The arrows illustrated in the Figures represent the
direction of flow of fluid to and from system 10, etc. The system
10 includes a pressure-controlled nozzle sealing member 30 which is
continuously moveable between a first closed position and a second
fully open position. As used herein, the terms "closed" and "open"
refer to the extent of sealing. The nozzle sealing member includes
an axisymmetric tapered seat region 34 of the nozzle sealing member
30 which contacts an axisymmetric seat region 38 adjacent the
radially inner and preferably longitudinal extremity of the jet
pump nozzle. The seat region 38 is formed in a first end of a
nozzle supply chamber 32. The nozzle sealing member's 30 travel
away from the first position towards the second position is
resisted by a resilient urging member 44, and motivated by fluid
pressure acting upon at least one reaction face 42. An annular area
of the nozzle sealing member 30's seat region 34 has a diameter
greater than that of the nozzle seat 38.
[0033] During operation, a predetermined threshold of fluid
pressure is required to overcome a predetermined force exerted by
the resilient urging member 44 to open the nozzle. This provides
control over the pressure of the discharge-to-load portion of the
present fluid pump system 10. In the exemplary embodiment, the
resilient urging member 44 is a compression spring. The nozzle
sealing member includes a sealing mobility portion 36 comprising a
valve body portion 40 adjacent to the spring 44 and opposite the
seat region 34. The spring side of the body 40 may include a
captured volume, 46 within the body 40. In the exemplary
embodiment, the spring 44 is positioned within the volume 46 and a
chamber 50. The volume 46 and chamber 50 are collectively referred
to herein as a "spring pocket" or damping chamber 54.
[0034] In the exemplary embodiment, the chamber 54 is vented to
atmospheric pressure through one or more damping orifice(s) 48 that
are positioned so as to allow escape of air. In one embodiment the
damping orifice 48 is in communication with a damping orifice oil
reservoir 52 (FIGS. 10-14) having volume greater than the
displacement of the nozzle sealing member's 30 travel. Any rapid
movement of the nozzle sealing member 30 is thus resisted by oil
viscosity in the damping orifice 48 after the spring pocket 54 has
been substantially purged of air and the damping orifice reservoir
filled by oil. The resulting motion damping of nozzle sealing
member 30 serves to smooth system pressure vis-a-vis positive pump
inherent displacement "ripple" and the tendency for structures
involving springs and masses to exhibit resonance. The venting to
atmosphere enables the system pressure to be controlled by the
force from urging member 44. Flow resistance characteristics of the
damping orifice 48 may be such that any leakage flow from the
nozzle supply chamber 32 to the spring pocket 54 is discharged to
the reservoir without pressure buildup in the spring pocket 54. The
nozzle sealing member 30 motion is allowed to be sufficiently
rapid, such as under cold startup conditions for example, to avoid
excessively high transient system pressure.
[0035] In the exemplary embodiment, the member body portion 40 and
the chamber 50 are cylindrical in shape. The body portion 40 and
chamber 50 thus form a piston and cylinder arrangement. It should
be appreciated, however, that the shape of the body portion 40 and
the corresponding chamber 50 may be altered, or alternative means
of sealing mobility with respect to the nozzle supply chamber may
be provided, without deviating from the scope of the claimed
invention.
[0036] The nozzle sealing member 30 is sealingly mobile with
respect to the second end of the nozzle supply chamber 32, and
positioned opposite the nozzle seat 38. This allows the fluid
pressure to act on the nozzle sealing member 30. When the fluid
pressure within the nozzle supply chamber 32 is below a first
threshold, the sealing member seat region 34 is in contact with the
nozzle seat 38. By maintaining the seal at low speeds, the desired
fluid pressure is maintained in the discharge passage 72 of a
positive displacement pump fluid 70, such as an internal tip
sealing rotor pump, commonly known as a gerotor pump. In one
embodiment, this sealing mobility may be provided by the
aforementioned piston and cylinder arrangement, but for embodiments
where sealing must be complete, or at least relatively leak-free,
alternative means of sealing mobility, such as a diaphragm or
bellows-type diaphragm apparatus for example, may be used. Nozzle
sealing member 30 position, and thus system pressure, automatically
adjusts in response to recirculation flow rate and viscosity of
fluid from the discharge passage 72 after exceeding the
predetermined threshold of fluid pressure. The nozzle sealing
member 30 is therefore independent of inlet pressure, or lack
thereof, with an advantageous reduction in complexity, size, and
cost.
[0037] JPV nozzle discharge flow, when present as illustrated by
the partially opened JPV of FIG. 2, is directed at consistently
high velocity by the axisymmetrically variable opening area between
the nozzle sealing member 30 and the nozzle seat 38, across an
annular gap or suction chamber 56 between the nozzle and a jet pump
throat passage 60 having adjacent throat inlet transition region
62. The throat passage 60 is also being fed, in this suction
chamber 56 region, by an uptake supply passage 66 referred to as a
"throat supply passage."
[0038] Fluid from the sump 64 is drawn into the suction chamber
region and adducted towards the nozzle discharge flow stream when
present, drawn into the throat inlet transition region, and then
into the throat itself where the two flows combine and momentums
are averaged as is characteristic of jet pump operation. The jet
pump throat passage 60 is in fluid communication with the inlet
passage 68 to the positive displacement oil pump 70, so as to apply
fluid pressure to this positive displacement pump's inlet passage
68 when the jet pump nozzle opens and delivers pressurized oil at
high velocity to the jet pump throat 60. The pressurization of the
positive displacement pump's inlet 68 provides advantages in
driving energy savings via so-called "hydraulic unloading," i.e.
the reduction of the pressure differential between the positive
displacement pump's inlet 68 and discharge passages 72.
Additionally, further advantages are gained in cavitation
deterrence, i.e. increase in the positive displacement pump's
pre-cavitation operating speed, via the enhanced pump filling that
the inlet passage's elevated fluid pressure motivates. At operating
conditions such as idle speed, and especially with hot oil, when
the system pressure is below the threshold required to open the
JPV, the positive displacement pump 70 draws its inlet flow from
the sump 64, through the jet pump's throat supply passage 66 and
the throat inlet transition region 62, and then the throat passage
60 itself, without the jet pump valve injecting fluid and thus
providing pressure increase.
[0039] The positive displacement pump's discharge passage 72 is in
captive fluid communication with both a consumptive load 74 and the
JPV's nozzle supply passage 76. This allows a recirculation circuit
to be formed from the pump's discharge 72, through the JPV nozzle
supply passage 76, nozzle supply chamber 32 and nozzle 38 and
throat 60, and then back to the pump's inlet passage 68. This fluid
circuit feeds unused pump output flow volumes forcibly back to the
pump's inlet 68 under pressure. The fluid circuit thus efficiently
"recycles" much of the pressure energy of the unused flow volumes,
in terms of the hydraulic work required of the pump. The exemplary
embodiment includes an appropriately proportioned diffuser 78
downstream of the JPV throat, for the recovery of velocity pressure
to the increase of static pressure, between the throat and the pump
inlet. However, an abbreviated diffuser, or no diffuser, are to be
understood as included in the scope of the claimed invention.
[0040] The spatial requirements for packaging flow-efficient
configurations of the JPV's nozzle supply chamber are preferably
minimized, along with side-loading of the JPV's sealingly mobile
interface, by providing a necked down portion 58 of the nozzle
sealing member 30 between its seat portion 34 and its sealingly
mobile or body portion 40. In this arrangement the nozzle supply
flow area in the nozzle supply chamber 32 is locally increased, to
locally reduce flow velocity, and thereby also the area exposed to
the incoming nozzle supply flow velocity is reduced. These area and
flow velocity differences result in reduced side-loading on the
nozzle sealing member 30 due to flow impingement, and consequently
wear may thereby be reduced.
[0041] While these embodiments offer efficiency advantages by
virtue of adjustable nozzle jet pump efficiency benefits and the
elimination of pressure losses across a separate flow control
valve, some application conditions will require measures to avoid
throat flow restriction at pre-boost operating conditions. In the
case of JPV applications that specify relatively high system
pressure before "cracking" or beginning of recirculation flow
(hereafter "high JPV cracking pressure systems"), the jet pump's
throat area may need to be larger than optimal for boost efficiency
in order to pass the entire inlet flow volume under atmospheric
pressure motivation alone prior to the onset of nozzle
discharge.
[0042] This throat size based efficiency limitation renders current
art fixed nozzle area single pump systems highly ineffective
because of the oversized jet pump throats necessary to avoid
choking their respective positive displacement pumps under some
operating conditions. Additionally, throat size based efficiency
limitation further renders current art fixed nozzle area single
pump systems highly ineffective because of the appreciable
recirculation flow volumes needed to achieve nozzle discharge
velocity dependent benefit from a fixed nozzle area jet pump.
[0043] In the case of high JPV cracking pressure systems, maximal
system efficiency over broad ranges of operating conditions may be
achieved, by means whereby the jet pump's throat can be allowed to
pass less than the entirety of system flow volume. This permits the
throat to be sized for efficiency rather than in light of pre-boost
flow velocity limitations. Two alternate embodiments provide a
means of circumventing this "throat restriction at pre-boost
operating conditions" issue, and thereby enabling optimal JPV
throat sizing. A first embodiment provides a parallel combination
of the single positive displacement pump with JPV recirculation
circuit arrangement as discussed above with a supplemental positive
displacement pump, whose supply passage is separate and independent
of the JPV's throat area. A second embodiment provides an
introduction of additional inlet supply flow capacity downstream of
the JPV's throat 60, between the jet pump's throat and the positive
displacement pump's inlet 68, hereafter the "throat-to-pump inlet
passage," through at least one one-way check valve to provide the
high flow capacity and low pressure drop characteristics needed to
sufficiently minimize inlet vacuum and thus avoid cavitation.
[0044] In case of the first embodiment including a supplemental
positive displacement pump, and referring now to the
cavitation-deterring energy-efficient fluid pump system 12 as
illustrated in FIG. 3, the flow volume from the sump 64 through
supplemental pump inlet passage 82 to supplemental pump 80, being
discharged to load 74 through supplemental pump discharge passage
84 acts to reduce the operating speeds at which unused oil becomes
available to "power" the JPV, thus lowering the critical speed for
which the jet pump throat passage 60 must be sized, an efficiency
advantage over the larger-than-optimal throat sizes of prior art
single pump systems. In this exemplary dual pump embodiment, the
JPV may also incorporate an integral pressure relief or "bypass"
port 86, which opens before the nozzle sealing member 30 has
reached its fully open second position. This allows an additional
flow route for the supplemental pump's flow volumes. This
additional flow route may be advantageous when operating at cold or
"deadhead" flow restriction conditions, or to avoid issues such as
overpressurizing seals, that of an oil filter for example. In the
exemplary embodiment, this integrated bypass port 86 is formed by
at least one opening or port in the wall of a cylindrical valve
bore 88 which maintains concentric location between the circular
cross-section nozzle sealing member's tapered sealing portion's
sealing area 34, and its conical seat region 38 in the nozzle
portion of the supply chamber 32. The bypass port 86 is positioned
so that it is only opened at the high pressure end of the nozzle
sealing member's 30 travel range. It should be appreciated that
sealing portion 34 and seat region 38 are described for exemplary
purposes as having a particular conical shape, however, other shape
types, such as a concave, convex or spherical surface for example,
could be used without deviating from the intended scope of the
claimed invention.
[0045] FIG. 4 schematically illustrates the cavitation-deterring
energy-efficient fluid pump system 12 illustrated in FIG. 3 with
nozzle sealing member 30 at a bypass threshold position where
further displacement from the first closed position towards the
second open position would enable fluid to escape through bypass
port (74) and return either to the reservoir 64 or, alternatively,
to the throat supply passage 66.
[0046] FIG. 5 schematically illustrates the system 12 with nozzle
sealing member 30 in the second fully open position whereby bypass
flow in bypass port 74 is enabled. The need for such pressure
relief functionality in a given system is not certain because the
unused portion of the supplemental pump's flow volume may be able
to escape through the JPV's nozzle, thus creating backflow out its
throat supply passage without exceeding engineering design
limitations on system pressure.
[0047] Another embodiment for avoiding having the entirety of
system supply flow volume to pass through the JPV throat 60 in high
JPV cracking pressure systems is illustrated in FIGS. 6-9. These
embodiments have one or more one-way (or check) valve(s) that may
be used to provide supplemental (i.e. in addition to that which
passes through the JPV's throat) intake flow to the positive
displacement pump 70 if needed prior to pressurization of the
throat-to-pump inlet passage. After pressurization of the positive
displacement pump's inlet 68 passage by jet pump action commences,
the one-way valve automatically closes to maintain the
pressurization, for "hydraulic unloading" energy savings and
cavitation speed increase.
[0048] FIG. 6 schematically illustrates a cavitation-deterring
energy-efficient fluid pump system 14 which enables optimal throat
sizing in a high JPV cracking pressure single pump system, namely
the addition of one or more one-way check valve inlet bypass
passage(s), such as a ball-type check valve 90 for example, having
inlet 96 that draws from the sump 64, and outlet 98 that discharges
to the throat-to-pump inlet passage 78 for introduction of supply
flow downstream of the JPV's throat 60. In this figure the system
pressure has not yet opened the JPV, yet the pump's inlet flow rate
is such that without flow through the check valve 90, the flow rate
through an optimally-sized jet pump's throat 60 might be high
enough to create substantial enough pressure drop across the throat
60 as to cause premature cavitation in the pump 70. The ball 92 is
shown in an elevated or open position above its valve seat 94 to
provide low resistance inlet flow to bypass the jet pump's throat
passage 60, thus reducing the vacuum magnitude of the positive
displacement pump's inlet passage 68 and thus avoiding premature
pump cavitation at times prior to the opening of the JPV.
[0049] FIG. 7 illustrates the same system with the ball 92 in a
seated or closed position, to resist loss of inlet boost pressure
after JPV opening. Such ball-type check valves are available both
with and without spring assist, the latter utilizing gravity to
seat the ball as illustrated in FIG. 7. While normally offering
more than adequate sealing performance, the employment of the
customary solid balls in this valve type may not be well suited to
highly vibratory applications such as balance shaft modules due to
the appreciable inertia forces associated with the mass of a solid
ball when confronted by aggressive vibration. The location and
configuration of the check-valved supply passage's union with the
positive displacement pump's throat-to-pump inlet passage are
arranged to minimize flow resistance while representing minimal
interruption of diffuser functionality, such as utilization of
Coanda effect shielded merging for example.
[0050] FIG. 8 illustrates the cavitation-deterring energy-efficient
fluid pump system 16 with a second alternate embodiment one-way
check valve 100 in the throat-bypassing supply passage 96,
utilizing a low cost, low mass, and vibration resistant type of
valve having a cup-shaped valve member 102 including a
substantially cup-shaped cross section. The cup shaped valve member
102 has sides that slidingly engage a cup piloting spring seat
member 104 for wear resistant locating of the bottom area of the
cup-shaped valve member 102. This provides for one-way sealing of a
substantially flat perimeter sealing surface 106 of the inlet
bypass passage 96. An optional cup-shaped valve member urging
member or spring 108 may aid gravity in urging the cup-shaped valve
member 102 gently towards closure or sealing without greatly
resisting bypass flow, when needed by certain applications. The
proportions and spring rate of this valve 100 configuration can be
tailored to provide very high flow capacity at very low pressure
drop. The cup-shaped valve member's 102 sides may be
circumferentially continuous or interrupted without departing from
their radial positioning functionality in interaction with the cup
piloting spring seat member 104.
[0051] FIG. 9 illustrates the cavitation-deterring energy-efficient
fluid pump system 18 with a third alternate embodiment check valved
inlet bypass having a so-called reed valve assembly check valve 110
positioned in the throat-bypassing supply passage 96. This kind of
multiple reed assembly 110 is used in the intake ports of high
performance two-stroke cycle engines and is capable of high flow
capacity concurrent with relatively low pressure drop. In one
embodiment, reed valves 112 are sealingly mounted to a sealing reed
frame member 114 that may also include reed travel stops 116. The
stops 116 provide motion control for the reed valves 112, including
the extent of their opening.
[0052] In some applications the predetermined threshold of pilot
pressure needed to open the JPV is allowed to be relatively low. In
these applications, the throat flow volume prior to commencement of
inlet pressurization is also commensurately low. Therefore, the
throat choking issue and the need for its avoidance, may be
irrelevant. Energy savings are maximized in this case because after
fully meeting an engine's hot idle flow requirements, only gradual
increase in engine system pressure with RPM is needed to overcome
the increased centripetal forces acting on the oil in crankshaft
oil passages. Any more than this gradual increase is typically
unnecessary for basic engine system performance. Therefore any
incremental increase in pressure, pump hydraulic loading and
driving torque, over that which is needed to assure this basic
system performance, represents wasted energy except where justified
by consumptive load devices that can more than make up for the
driving torque increase by their contributions to engine
performance.
[0053] Referring now to FIG. 10, an alternate cavitation-deterring
energy-efficient fluid pump system 20 is illustrated. In cases
where the pressure drop across an oil filter and/or other
consumptive load flow resistance is considered to have a larger
than desired deviation between the system delivery pressure as
managed by the JPV, and the system pressure downstream of this
resistance, the introduction of a cavitation-deterring
energy-efficient fluid pump system 20 with a nozzle supply chamber
sealing partition 118 is provided. This nozzle supply chamber
sealing partition 118 allows sealing mobility of the cylindrical
nozzle sealing member support 120 that is arranged between the seat
34 of nozzle sealing member 30 and its body portion 40. The
partition 118 separates the sealingly mobile pressure reaction face
area 42 of the nozzle sealing member 30 from the nozzle supply
chamber 32. This allows the exposure of face 42 to a pilot pressure
chamber 122. The pilot pressure chamber 122 provides exposure of
the face 42 to the downstream of resistance pilot pressure 124
rather than the fluid pressure from the discharge passage 72. The
downstream of resistance pilot pressure 124 may be represented by
an engine's oil gallery downstream of its filter system flow
resistance for example. The use of the pilot pressure chamber 122
to actuate the nozzle sealing member 30 may be referred to as
"remote pilot" control.
[0054] The cavitation-deterring energy-efficient fluid pump system
is advantageous when integrated into engine applications such as
Lanchester-type balance shaft modules where pump driving torques
offer cost-effective drive system noise control synergies, and yet
where packaging space constraints prohibit the use of more complex
variable-displacement pump configurations. The embodiments
disclosed herein, such as the positive displacement pump 70, the
diffuser 66, and the JPV, form a fluid circuit "chain." This chain
provides considerable packaging flexibility in comparison with the
substantially more complex variable-displacement pump
configurations, which require mechanical proximity of all key
elements.
[0055] At least one embodiment thus combines the
cavitation-deterring energy-efficient fluid pump system with at
least one engine balancing shaft to form a balance shaft/oil pump
apparatus (FIG. 19) for control of gear noise emissions at minimum
cost. Such balance shaft/oil pump modules are typically very highly
constrained, in terms of available packaging space, because they
are usually housed below the engine's crankshaft, and therefore
compete for available space with the engine's oil volume in the oil
pan or wet sump, the oil level needing to stay below the level of
the spinning crankshaft and its connecting rods in order to avoid
needless oil aeration, oil heating, and power consumption. The
spatial requirements for packaging flow-efficient configurations of
a jet pump's typically largest diameter feature, namely its suction
chamber, are a function of the advantages of smooth acceleration of
the radially inward adduction flow approaching the throat 60. This
is conventionally significant, diameter-wise, in order to establish
the substantially axisymmetric adduction flow pattern for most
efficient energy transfer between nozzle discharge flow and suction
chamber flow as they enter, past the throat inlet transition
region, into the throat passage itself.
[0056] FIG. 10 illustrates an embodiment for minimizing the
diameter of the suction chamber in order to facilitate compact
packaging. In this embodiment, the throat supply passage 66 is
located adjacent to a necked-down region 126 behind (i.e. remote
from the suction chamber) a throat entry horn. The throat passage
60 includes a throat inlet transition region 62 such that
substantially uniform axial flow can supply the perimeter of the
horn. The flow in this region 62 is substantially free from
"crosswind" effects from throat supply passage 66 flow velocity.
The necked down region circumscribing the throat passage 60 lowers
the velocity of the flow from the throat supply passage 66. This
allows the throat supply passage 66 to be a low restriction "elbow"
that aligns the flow from the throat supply passage 66 towards the
suction chamber 56 into being substantially coaxial with the throat
passage 60.
[0057] In this embodiment, the substantially uniform gap around the
bell of the throat entry horn acts to produce substantially uniform
flow velocity all around its periphery. This is advantageous in
providing the desired axisymmetric flow pattern approaching the
throat supply passage 66. Even if the throat supply passage 66 is
not entirely behind the throat entry horn 62, such a necked down
region can be helpful towards reducing crosswind asymmetry of
throat inlet transition region flow by increasing flow area without
a corresponding increase in suction chamber diameter. In adverse
packaging space conditions where fully axisymmetric suction chamber
designs are impractical, such flow area improvements as necking
behind a throat entry horn 62 can be of particular value in a
compromise solution optimized by numerical methods, such as
computational fluid dynamics methods for example. The embodiment of
FIG. 10 further includes a vented-to-atmospheric damping reservoir
52 in fluid communication with the nozzle sealing member 30 motion
control means of damping orifice 48.
[0058] FIG. 11 illustrates the cavitation-deterring
energy-efficient fluid pump system 20 with the addition of an
optional pilot pressure chamber seal 128 that may be utilized to
minimize leakage between the cylindrical nozzle sealing member
support 120 of the nozzle sealing member 30 and the nozzle supply
sealing partition 118. Such a seal, if desired, may be oriented to
withstand the always-higher pressure of the nozzle supply chamber
32.
[0059] In some applications, electronic or other logic based
automated control of system pressure may be desired in order to
increase system delivery flow rates under certain operating
conditions, such as the opening of a piston cooling jet manifold
valve for example. The nozzle-closing force of the resilient urging
member 44 may be supplied, or else supplemented, by a control
apparatus such as an electronic or electromechanical actuation
device for example. FIG. 12 illustrates a cavitation-deterring
energy-efficient fluid pump system 22 having such an electronic
control means 130 as supplementation to a resilient urging member
44. It should be appreciated that the electronic control means 130
may be coupled to one or more sensors (not shown) that provide
feedback signals indicating operating conditions such as pressure
of the fluid either within the cavitation-deterring
energy-efficient fluid pump system 22 or the consumptive load for
example. The electronic control means 130 is responsive to these
signals in actuating the nozzle sealing member 30. The electronic
control means 130 may be further responsive to pressure on the face
42 and activate based on the amount of pressure in supply chamber
32. Also shown is the necked down portion 58 of the nozzle sealing
member 30 between the seat portion 34 and the body portion 40 as
discussed above. It should be appreciated that such a control
device 130 maybe used alone as the urging member. Typically
electromagnetic solenoids are used for electronic actuation,
however, their continual power draw when exerting a control force
is counterproductive to net energy efficiency. Therefore, the use
of alternative devices may be desirable.
[0060] FIG. 13 illustrates a cavitation-deterring energy-efficient
fluid pump system 24 with the optional combination of both remote
pilot pressure 124 and electronic pressure control means 130,
whereby system pressure is passively managed to maintain threshold
downstream-of-resistance targets, and may additionally be actively
managed for specific purposes when desired.
[0061] FIG. 14 illustrates an alternate embodiment
cavitation-deterring energy--efficient fluid pump system 25 having
actuation of the nozzle sealing member 30 by the electronic control
means 130 without the assistance of spring 44. In this embodiment,
the electronic control means 130 includes a plunger 132. The
plunger 132 is coupled to the body portion 40 and arranged to be
moved linearly along an axis parallel to the axis of the nozzle
sealing member 30. This movement causes the sealing seat 34 of
member 30 to move into and out of contact with nozzle seat 38.
[0062] [In applications where the sealingly mobile functionality of
the nozzle sealing member 30 with respect to the nozzle supply
chamber 32 must be nearly leak-free, a piston and cylinder type
apparatus may be fitted with at least one o-ring or other sealing
device. In other applications where the sealingly mobile
functionality of the nozzle sealing member 30 and chamber 32 must
be completely leak-free, a sealing mobility portion 36 comprising a
diaphragm-type apparatus, including bellows-type diaphragm may also
be used. FIG. 15 illustrates such a sealingly mobile diaphragm type
cavitation-deterring energy-efficient fluid pump system 26. In this
embodiment, a sealing tip 136 is coupled to the body portion 142 of
the nozzle sealing member 30. The sealing tip 136 includes a seat
area 138 that contacts the nozzle seat 38 when the sealing member
30 is in the first position. A diaphragm member 140 is also coupled
to the body portion 142. The diaphragm member 140 provides the
reaction surface upon which the fluid pressure from discharge
passage 72 acts. The spring 44 biases the sealing tip 136 into
contact with the nozzle seat 38.
[0063] It should be appreciated that other types and constructions
of sealing mobility portion 36's diaphragm type
cavitation-deterring energy-efficient fluid pump system 26 may be
used. For example, the diaphragm member 140 may be bonded to the
sealing tip 136, or a formed protrusion of the diaphragm may be
press fit onto the sealing tip 136. This would allow the
elimination of the spring guide. Further, the diaphragm member 140
may be used itself as the urging member allowing the elimination of
the separate spring.
[0064] FIG. 16 illustrates a cavitation-deterring energy-efficient
fluid pump system 28 wherein leak-free sealing mobility of the
JPV's nozzle sealing member with respect to the nozzle supply
cavity is provided by a bellows type diaphragm. In this embodiment,
the spring 44 acts upon a body portion 142 as described herein
above. The body portion 142 is coupled to a sealing body 144.
Sealing body 144 includes a seat region 146 that contacts the
nozzle seat 38 when the sealing member 30 is in the first position.
The sealing body 144 is generally cone shaped and includes a pilot
flange portion 148 that is axially mobile within a pilot diameter
150. A bellows member 152 is coupled to the body portion 142. The
bellows member's 152 minor diameter represents the outside of the
functional area of pressure reaction face 42, so this diameter is
sized in conjunction with mating component properties such as
nozzle seat diameter, urging member static force and rate of force
change (e.g. spring rate), in light of desired system fluid
pressure range. A damping orifice 154 is arranged in the spring
pocket 54 opposite the body portion 142. During operation, the
bellows member 152 compresses and expands axially to enable nozzle
sealing member 30 motion within nozzle supply chamber 32. During
this motion, the large pilot flange 148 is able to "leak" oil back
and forth to the diaphragm OD region.
[0065] FIG. 17 illustrates a cavitation-deterring energy-efficient
fluid pump system 29 having an electronic control means 156 similar
to control means 130 discussed above in reference to FIG. 12.
Control means 156 acts on the spring 44 instead of acting directly
on the nozzle sealing member 30. The control means 156 includes an
actuator, such as a solenoid or a stepper motor for example, that
actuates a spring support 158. The spring support 158 has a spring
support face 160 that may be moved linearly by the control means
156 from a first or initial position to a second position in
response to a switching event. The movement of the spring support
158 changes the amount of compression of spring 44, and thus the
magnitude of the force provided by spring 44. In the exemplary
embodiment, the spring support 158 may be held at the second
position without further energy expenditure. The spring support 158
may remain in this position until another switching event, such as
the closing of a piston cooling jet manifold valve for example,
causes the control means 156 to restores the spring support 158 to
the initial position. This embodiment provides the advantage of
using a normally passive type electronic control 156 such as a
stepping motor instead of an electronic control such as a solenoid
that continually draws power in order to exert an axial force. Such
a normally passive electronic control 156 may be activated when a
significant change to engine permeability occurs, such as the
opening of a piston cooling jet manifold valve for example. This
type of activation may result in a desired new degree of spring 44
preload that may be used to maintain system pressure under such a
higher permeability condition. This preload of the spring 44 may
then be maintained without need for the control 156 to actively
respond to system pressure changes. This use of a normally passive
type electronic control provides the advantage of increased energy
savings in comparison with an electronic control that requires
continual electrical power to exert a force.
[0066] FIG. 18 illustrates empirical test data comparing the
pressure curves of a conventional PRV-regulated single positive
displacement pump and a FIG. 1 cavitation-deterring
energy-efficient fluid pump system ("C-dE-EFPS") 10. The test setup
between the two tests differed only in respective hydraulics, as
needed to achieve a hypothetical high-speed pressure requirement.
The PRV testing results are defined by dashed-line 158, while that
of the exemplary embodiment fluid pump system 10 is defined by line
160. The PRV system recirculates its bypass oil directly back to
the pump's inlet, merging with sump uptake oil in a favorable
direction within 1 cm of the pump, in a routing commonly termed
"supercharging." As can be seen from curve 158, the PRV-regulated
system pressure begins to falter at point 166 due to cavitation
beginning around 5200 rpm, while the inlet pressurization benefit
of the C-dE-EFPS 10 enables its outlet pressure to rise steadily to
nearly 8000 rpm.
[0067] FIG. 19 compares empirical drive system power consumption
curves for the FIG. 17 test conditions. The PRV test results are
defined by dashed-line 168, while those of the fluid pump system 10
is defined by line 170. The approximately 19% average difference in
drive system power consumption over the most frequently-used speed
range understates the actual pump power consumption difference,
because the drive system friction losses (from spindle bearings,
spindle seals, chain, sprockets, chain tensioner and chain guide)
are also included in these curves.
[0068] The cavitation-deterring energy-efficient fluid pump system
may be used in a number of applications. FIG. 20 illustrates one
such application where the cavitation-deterring energy-efficient
pump system 172, including a positive displacement pump 174
arranged with an adjustable nozzle jet pump valve 178 and reservoir
180 as described embodiments illustrated in FIGS. 1-16, is coupled
to a balance shaft modular assembly 184. The positive displacement
pump 174 includes a discharge passage 182 that transfers fluid,
such as a petroleum-based lubricant, to the engine 186 through a
filter 194. The positive displacement pump 174 is drivingly
connected to the engine 186 that provides the energy for operation
of the positive displacement pump 174. In the connection 176 the
positive displacement pump 174 is mechanically connected.
[0069] The modular assembly 184 delivers the fluid to an engine
186, such as an internal combustion engine for example. In the
exemplary embodiment, the engine 186 includes one or more pistons
188, each with a connecting rod assembly 190. The delivered fluid
is cleaned by filter 194 and then used within both engine 186 and
modular assembly 184 before being returned to reservoir 180 via at
least one return passage 192.
[0070] The embodiments described herein provide a
cavitation-deterring energy-efficient fluid pump system that
provides advantages in extending the working speed range of a
positive displacement pump. The cavitation-deterring
energy-efficient fluid pump system further provides advantages in
reducing the driving power consumption of a positive displacement
pump over its typical operating speed range. Additional advantages
are made in minimizing the packaging space claim of a positive
displacement pump system having jet pump-assisted recirculation,
and to enable its design flexibility with regards to application
packaging constraints. Additional advantages are provided to
minimize manufacturing costs. The cavitation-deterring
energy-efficient fluid pump system also provides advantages in
enabling control by means remote from the positive displacement
pump's output pressure where so desired.
[0071] The embodiments described herein provide further
improvements in that the aforementioned differential control means
of prior art valve mechanisms are larger, and thus disadvantaged in
terms of packageability and cost, for any given combination of
urging force and nozzle flow capacity. In comparison, the
embodiments provided herein include further advantages because the
valve motion motivating pressure area of prior art mechanisms is
reduced by both the nozzle seat area and that of the smaller of two
piston diameters. Further, the fluid pressure acting on this
reduced pressure area is only the net difference between the output
pressure and the input pressure, with the input pressure typically
being positive. In comparison, the valve motion motivating pressure
area of the embodiments provided herein is reduced by only the
nozzle seat area, and the fluid pressure acting on this pressure
area is not influenced by inlet pressure.
[0072] While the present invention has been described with
reference to preferred embodiments, obviously other embodiments,
modifications, and alternations could be envisioned by one skilled
in the art upon reading the present disclosure. The present
invention is intended to cover these other embodiments,
modifications, and alterations that fall within the scope of the
invention upon reading and understanding this specification with
its appended claims.
* * * * *