U.S. patent application number 12/816412 was filed with the patent office on 2011-12-22 for method and apparatus to regulate coolant pump inlet pressure.
Invention is credited to Scott Hayes, Russell Peterson, Alan Sheidler, Jonathan Spooner.
Application Number | 20110308484 12/816412 |
Document ID | / |
Family ID | 45327536 |
Filed Date | 2011-12-22 |
United States Patent
Application |
20110308484 |
Kind Code |
A1 |
Peterson; Russell ; et
al. |
December 22, 2011 |
METHOD AND APPARATUS TO REGULATE COOLANT PUMP INLET PRESSURE
Abstract
A method of regulating coolant pump inlet pressure of an
internal combustion engine, the method including the steps of
producing pressurized air by way of a mechanism and directing a
portion of the pressurized air coming from the mechanism to a
coolant system of the internal combustion engine.
Inventors: |
Peterson; Russell;
(Waterloo, IA) ; Sheidler; Alan; (Moline, IL)
; Spooner; Jonathan; (Waterloo, IA) ; Hayes;
Scott; (Cedar Falls, IA) |
Family ID: |
45327536 |
Appl. No.: |
12/816412 |
Filed: |
June 16, 2010 |
Current U.S.
Class: |
123/41.44 ;
123/41.01 |
Current CPC
Class: |
F01P 11/18 20130101;
F01P 3/20 20130101; F01P 11/029 20130101 |
Class at
Publication: |
123/41.44 ;
123/41.01 |
International
Class: |
F01P 5/10 20060101
F01P005/10 |
Claims
1. A method of regulating coolant pump inlet pressure of an
internal combustion engine, the method comprising the steps of:
producing pressurized air by way of a mechanism; and directing a
portion of said pressurized air coming from said mechanism to a
coolant system of the internal combustion engine.
2. The method of claim 1, wherein said directing step includes the
step of regulating a pressure of said portion of pressurized air
going to said coolant system.
3. The method of claim 1, wherein said mechanism is a
turbocharger.
4. The method of claim 3, further comprising the step of passing
air from said turbocharger through a cooling device before carrying
out said directing step.
5. The method of claim 3, further comprising the step of limiting a
flow of air from said turbocharger to become said portion of
air.
6. The method of claim 5, further comprising the step of regulating
air pressure in said coolant system.
7. The method of claim 6, wherein said step of regulating air
pressure is carried out by way of a pressure regulator that
regulates a pressure of said portion of air before said portion of
air arrives at a surge tank of said coolant system.
8. The method of claim 6, wherein said step of regulating air
pressure is carried out by way of a pressure regulator that bleeds
air from a surge tank of said coolant system to thereby regulate
air pressure in said coolant system.
9. A vehicle using an internal combustion engine, comprising: a
chassis coupled to the engine, the engine having a cooling system;
an air pressurizing device configured to compress air; and a surge
tank fluidly coupled to said cooling system, said surge tank
coupled to said air pressurizing device to thereby receive a
portion of the compressed air.
10. The vehicle of claim 9, wherein the portion of the compressed
air is sent to said surge tank at a predetermined regulated
pressure.
11. The vehicle of claim 9, wherein said air pressurizing device is
a turbocharger.
12. The vehicle of claim 11, further comprising a pressure
regulator positioned downstream from said turbocharger, said
pressure regulator being fluidly coupled to said surge tank, said
pressure regulator being positioned one of upstream from said surge
tank and downstream from said surge tank.
13. The vehicle of claim 12, further comprising a flow limiting
device fluidly coupled to said turbocharger downstream from said
turbocharger, said flow limiting device being upstream of said
pressure regulator.
14. The vehicle of claim 11, further comprising an air cooling
device coupled to said turbocharger downstream from said
turbocharger, the portion of the compressed air being directed to
said surge tank after traversing said air cooling device.
15. An internal combustion engine, comprising: a cooling system; an
air pressurizing device configured to compress air; and a surge
tank fluidly coupled to said cooling system, said surge tank
coupled to said air pressurizing device to thereby receive a
portion of the compressed air.
16. The internal combustion engine of claim 15, wherein the portion
of the compressed air is sent to said surge tank at a predetermined
regulated pressure.
17. The internal combustion engine of claim 15, wherein said air
pressurizing device is a turbocharger.
18. The internal combustion engine of claim 17, further comprising
a pressure regulator positioned downstream from said turbocharger,
said pressure regulator being fluidly coupled to said surge tank,
said pressure regulator being positioned one of upstream from said
surge tank and downstream from said surge tank.
19. The internal combustion engine of claim 18, further comprising
a flow limiting device fluidly coupled to said turbocharger
downstream from said turbocharger, said flow limiting device being
upstream of said pressure regulator.
20. The internal combustion engine of claim 17, further comprising
an air cooling device coupled to said turbocharger downstream from
said turbocharger, the portion of the compressed air being directed
to said surge tank after traversing said air cooling device.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to internal combustion engine
systems, and, more particularly, to coolant control systems
utilized by internal combustion engines.
[0003] 2. Description of the Related Art
[0004] An internal combustion (IC) engine may include an exhaust
gas recirculation (EGR) system for controlling the generation of
undesirable pollutant gasses and particulate matter in the
operation of IC engines. EGR systems primarily recirculate the
exhaust gas byproducts into the intake air supply of the IC engine.
The exhaust gas, which is reintroduced to the engine cylinder,
reduces the concentration of oxygen therein, which, in turn, lowers
the maximum combustion temperature within the cylinder and slows
the chemical reaction of the combustion process, decreasing the
formation of nitrous oxides (NOx). Furthermore, the exhaust gasses
typically contain unburned hydrocarbons, which are burned on
reintroduction into the engine cylinder, which further reduces the
emission of exhaust gas byproducts which would be emitted as
undesirable pollutants from the IC engine.
[0005] An IC engine may also include one or more turbochargers for
compressing an air supply, which is supplied to one or more
combustion chambers within the IC engine. Each turbocharger
typically includes a turbine driven by the exhaust gasses of the
engine and a compressor, which is driven by the turbine. The
compressor receives the air to be compressed and supplies the air
to the combustion chambers. When utilizing the EGR in a
turbocharged diesel engine, the IC engine may use an EGR cooler to
cool the exhaust gas before introduction into the engine.
[0006] Tier 4 emission requirements are driving the use of larger
EGR coolers and higher capacity coolant pumps to provide adequate
coolant flow to carry away the heat released in the EGR cooler. In
order for the EGR cooler to function properly and enable the
emissions controls to function correctly, an uninterrupted flow of
coolant must be supplied to the EGR cooler. If the coolant flow is
interrupted for any reason, there is a possibility of the IC engine
not being emissions compliant. In addition, damage due to localized
boiling inside the EGR cooler causes cracks that may result in
coolant leaks and downtime. One of the most significant causes of
coolant flow interruption is coolant pump cavitation. Cavitation
can occur when the coolant pump inlet pressure drops to a level
below which discrete vapor bubbles (steam) can form at the inlet of
the pump or in the pump impeller. Small amounts of cavitation are
generally not damaging but, if enough cavitation occurs, flow can
be disrupted to the point where coolant flow is significantly
decreased and cooling efficiency is reduced. Heat exchangers, such
as an engine oil cooler, cooling radiator, and EGR cooler will not
function properly if the coolant flow is reduced. Damage to those
heat exchangers may occur as well as damage to the engine due to
overheating.
[0007] The current state of the art is to close the cooling system
so that the pressure naturally builds as the engine heats up during
normal running conditions. This is due to and is reliant upon the
natural tendency of coolant (typically a mixture of water and
antifreeze) to release vapor in proportion to its temperature and
also to the change in volume of the liquid coolant as the
temperature changes. If the system is closed and sealed off from
the surroundings, the pressure within the system will build because
the water vapor is contained inside the pressure tight engine and
cooling system. The system is provided with a pressure cap on the
surge tank which has a relief valve to release air and vapor from
the system if the pressure exceeds the pressure safety limit. The
term surge tank is the reservoir from which coolant is drawn from
and to which if flows from the rest of the coolant system as the
temperature, pressure and volume of the coolant vary during use of
the engine. This system generally provides adequate pressure
control to maintain a high enough positive coolant pump inlet
pressure to minimize cavitation. However, there are times when the
current state of the art may not be capable of providing sufficient
pressure to eliminate cavitation. Examples of this are during
transient load variations when the engine is heating up or cooling
down rapidly and insufficient vapor pressure has developed quickly
enough to avoid cavitation in sensitive areas of the system.
[0008] One solution is to monitor the pressure at the coolant pump
inlet and to sense when the pressure is too low relative to the
observed coolant temperature, which could result in cavitation. The
controller would then determine that cavitation is possible and
electronically command the EGR valve to close to stop hot EGR gas
from entering the EGR cooler where it could damage the cooler.
Because the EGR flow is cut off, the engine may not be emissions
compliant. If the engine is not compliant regarding emissions it is
considered a violation of the auxiliary emission control device
(AECD) by the EPA, and a warning signal must be given to the
operator and the engine has to be derated so that the operator is
forced to stop the machine and render whatever service is required
to remedy the situation that caused the AECD operation to be
interrupted. Another problem is that this situation is such that
there is really nothing that the operator can do, that is currently
known to remedy the situation other than to either reduce the load
or to shut the machine down and let it cool down to an ambient
temperature before restarting. If the operator removes the pressure
cap while the engine is hot, which can be a typical operator
response, the system pressure drops to zero, thus virtually
guaranteeing that there will be coolant pump cavitation and EGR
cooler damage.
[0009] What is needed in the art is a cooling system that maintains
pressure therein to effectively reduce of eliminate cavitation. A
better way is needed to control and maintain the cooling system
pressure to prevent the cavitation that can lead to damage to
various engine systems, as is presently the case with the current
state of the art.
SUMMARY OF THE INVENTION
[0010] The present invention in one form thereof, is a method of
regulating coolant pump inlet pressure of an internal combustion
engine, the method including the steps of producing pressurized air
by way of a mechanism and directing a portion of the pressurized
air coming from the mechanism to a coolant system of the internal
combustion engine.
[0011] In another form, the invention includes an internal
combustion engine having a cooling system, an air pressurizing
device configured to compress air, and a surge tank fluidly coupled
to the cooling system. The surge tank is coupled to the air
pressurizing device to thereby receive a portion of the compressed
air.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The above-mentioned and other features and advantages of
this invention, and the manner of attaining them, will become more
apparent and the invention will be better understood by reference
to the following description of embodiments of the invention taken
in conjunction with the accompanying drawings, wherein:
[0013] FIG. 1 illustrates a vehicle having an engine that utilizes
an embodiment of the method and apparatus to regulate coolant pump
inlet pressure of the present invention;
[0014] FIG. 2 is a schematic illustration of one embodiment of the
method utilized in the engine of FIG. 1;
[0015] FIG. 3 is a schematic illustration of another embodiment of
the method utilized by the engine of FIG. 1; and
[0016] FIG. 4 is a schematic illustration of yet another embodiment
of the method utilized with the engine of FIG. 1.
[0017] Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplifications set out
herein illustrate embodiments of the invention and such
exemplifications are not to be construed as limiting the scope of
the invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Referring now to the drawings, and more particularly to FIG.
1, there is shown a vehicle 10 which may be in the form of
agricultural vehicle or a tractor. Vehicle 10 includes a chassis 12
to provide physical support for an engine system 14.
[0019] Now, additionally referring to FIG. 2, there is illustrated
in schematic form engine system 14 including an engine 16, having
an engine air intake 18, and a cooling system 20. Engine 16
includes the EGR system previously discussed and other heat
producing elements therein, the heat therefrom being substantially
removed by cooling system 20.
[0020] Cooling system 20 includes a coolant pump 22, a radiator 24,
a surge tank 26, a fill line 28, a vent line 30, and coolant 32.
Coolant pump 22 is driven by engine 16 causing a flow of coolant as
shown in the figure. Although coolant pump 22 is described as being
driven by engine 16, other methods of powering coolant pump 22 are
contemplated, such as electrically driving coolant pump 22. Coolant
flows through engine 16, heat is transferred from engine 16 to the
coolant and the coolant is then directed to radiator 24, which
cools the coolant by way of the passage of ambient air through the
heat exchanging arrangement. As the temperature changes in engine
system 14, the size of the components being cooled, as well as the
fluid itself, expands and contracts over the heating/cooling cycles
of the engine system 14. In order to accommodate the change in
fluid capacity and the density of the fluid, surge tank 26 has a
level of coolant 32 that provides coolant to coolant pump 22 when
needed. Fill line 30 provides coolant 32 to coolant pump 22 and
vent line 34 allows any air, vapor and/or gases to be removed from
engine 16 and passed to surge tank 26.
[0021] Engine system 14 additionally includes a turbocharger 34,
that provides a primary airflow 36 and a cooler 38 for the cooling
of the compressed air flowing therethrough. Turbocharger 34 is an
air compressing or pressurizing device that may be driven
mechanically or by a turbine powered by the exhaust gasses coming
from engine 16. Air enters turbocharger 34 and is pressurized as it
flows therefrom.
[0022] Coolant system pressurizing system 40 includes a pressure
relief cap 42, an orifice 44, a check valve 46, a pressure
regulator 48, and a low pressure valve 50. Pressure relief cap 42
is illustrated schematically having a relief pressure feature that
may, for example, be configured to release pressure from within
surge tank 26 if it exceeds, for example, 125 kPa. Pressure relief
cap 42 is similar to those provided on conventional equipment. Low
pressure valve 50 may also be a feature of pressure relief cap 42
illustrated here schematically as allowing air back into surge tank
26 if pressure therein drops below the ambient pressure. For
example, low pressure valve 50 may allow the ambient air to enter
surge tank 26 when the pressure within surge tank 26 is, for
example, 7 kPa below the ambient air pressure.
[0023] Air that has been compressed by turbocharger 34 is primarily
directed to engine 16. A small portion of the air passes through an
orifice 44, which serves as a flow reducing device. Check valve 46
is provided to prevent any backflow from surge tank 26 from
entering into the turbocharger system that is supplying air to
engine 16. Pressure regulator 48 regulates the pressure of the air
passed to surge tank 26 based on a predetermined setting thereof.
The predetermined setting may be, for example, 100 kPa, thereby
providing the compressed or pressurized air to surge tank 26, which
then of course pressurizes coolant 32. In this embodiment of the
present invention, the airflow passes downstream from turbocharger
34 to orifice 44 through check valve 46, through pressure regulator
48 and arrives at surge tank 26.
[0024] Now, additionally referring to FIG. 3, there is illustrated
another embodiment of engine system 14, having a cooling system
pressurizing system 140 having components that are similar to those
of the previous embodiment with their number increased by 100 for
the ease of explanation. Cooling system pressurizing system 140
includes an orifice 144, a check valve 146, and a pressure
regulator 148. In this embodiment, orifice 144 receives pressurized
air after it has passed through cooler 38. The embodiment of FIG. 2
could likewise have received air from this location rather than
prior to air cooler 38. Check valve 146 functions similarly to
check valve 46. In this embodiment, pressure regulator 148
functions to control pressure within surge tank 26, allowing the
flow of air to flow through orifice 144, and check valve 146, to
arrive at surge tank 26 and then any excess pressure is regulated
by way of pressure regulator 148. Pressure regulator 148 may be set
to 100 kPa or approximately 1 atmosphere of pressure and then
regulate any over pressure that may be introduced into surge tank
26 by bleeding off the excess air. Pressure relief cap 42 is still
provided to allow for large increases of pressure not capable of
being regulated by pressure regulator 148. In this embodiment, as
long as engine 16 is running, turbocharger 34 provides air through
orifice 144 based upon the flow restriction of orifice 144 and then
excess air is bled off by way of pressure regulator 148.
[0025] Now, additionally referring to FIG. 4, there is illustrated
engine system 14 having a pressurizing system 240 with elements of
pressurizing system 240 being similar to those of FIGS. 2 and 3
with the similar elements being increased numerically by another
100. In this embodiment, orifice 244 is placed downstream of
turbocharger 34 but upstream from cooler 38. The portion of air
traveling through orifice 244, is similar to the previous
embodiment, travels through check valve 246, supplying pressurized
air to surge tank 26. The pressure therein being regulated by
pressure regulator 248. All of the embodiments herein utilize
pressurized air driven from a mechanism of engine system 14 with
the flow being reduced and regulated as it is either supplied to
surge tank 26 or the air pressure therein is regulated after the
air is introduced.
[0026] The present invention provides a system with active
pressurization of coolant system 20 independent of the generation
of vapor pressure in response to system temperature changes. This
is done by tapping into the turbocharger 34 outlet with orifice 44,
144, 244 connected to check valve 46, 146, 246 and pressure
regulator 48, 148, 248. These elements provide for a small bleed
air charge at a carefully controlled pressure to be supplied to
surge tank 26 to quickly build the coolant system 20 system
pressure and also to provide make up air for situations when engine
16 is rapidly cooling, causing the coolant volume to decrease and
pressure to fall. The present invention also serves to supplement
the accumulator effect of trapped air volume within surge tank 26.
Yet further, if it happens that there is a small leak in coolant
system 20, the system provides for make up air to keep coolant
system 20 pressurized. This includes, for example, compensation for
a partially failed pressure cap, that is not seated properly, has a
defective seal, or is defective from the manufacturer. In this way,
small leaks of coolant system 20 are rendered harmless. If a
coolant leak exists, coolant could be lost, but the system would
remain pressurized, no matter how much coolant is lost, thus
guaranteeing safe operation of coolant pump 22, the EGR cooler, and
other cavitation sensitive components.
[0027] Surge tank 26 can additionally be equipped with a coolant
level sensor to warn the operator that the coolant level has
decreased below the minimum allowable set point. A system derating
would not have to be imposed, however, because the coolant level at
the warning set point would still be high enough for the system to
operate. If the operator ignores the warning, and the coolant level
drops more, a second stage to the level sensor can be actuated to
engage a safety alarm to shut down the engine. Another such alarm
can be provided to monitor the engine temperature, which will also
warn the operator to shut down the engine if the temperature
exceeds the maximum temperature set point.
[0028] The present invention virtually eliminates, or at least
reduces, the possibility for cavitation and its damaging system
effects. It also eliminates the need for expensive additional
pressure sensors and ECU software algorithms, which may not serve
to enhance the function or reliability of the engine system. The
present invention works with existing system components, sensors,
and operator interfaces and eliminates the likelihood of annoying
coolant pressure reductions, which will result in downtime and user
dissatisfaction with the engine or vehicle 10.
[0029] While this invention has been described with respect to at
least one embodiment, the present invention can be further modified
within the spirit and scope of this disclosure. This application is
therefore intended to cover any variations, uses, or adaptations of
the invention using its general principles. Further, this
application is intended to cover such departures from the present
disclosure as come within known or customary practice in the art to
which this invention pertains and which fall within the limits of
the appended claims.
* * * * *