U.S. patent application number 13/328142 was filed with the patent office on 2013-06-20 for cooling system with dual reversing fans.
The applicant listed for this patent is John M. Chesterman, David R. Didelot, Karl G. Heine, Joseph M. Montocchio, Boyd M. Nichols, Carl R. Starkey. Invention is credited to John M. Chesterman, David R. Didelot, Karl G. Heine, Joseph M. Montocchio, Boyd M. Nichols, Carl R. Starkey.
Application Number | 20130153180 13/328142 |
Document ID | / |
Family ID | 48608928 |
Filed Date | 2013-06-20 |
United States Patent
Application |
20130153180 |
Kind Code |
A1 |
Montocchio; Joseph M. ; et
al. |
June 20, 2013 |
Cooling System With Dual Reversing Fans
Abstract
A cooling system comprises a first cooling package, a second
cooling package, and a fan control system. The first cooling
package comprises a first fan and at least one heat exchanger to
cool at least one fluid associated with the machine. The first fan
is configured to rotate in a cooling direction and an opposite
cleaning direction. The second cooling package comprises a second
fan and at least one heat exchanger to cool at least one fluid
associated with the machine. The second fan is configured to rotate
in a cooling direction and an opposite cleaning direction. The fan
control system is configured to alternate the first and second fans
between a first cleaning mode and a second cleaning mode.
Inventors: |
Montocchio; Joseph M.;
(Dubuque, IA) ; Didelot; David R.; (Asbury,
IA) ; Heine; Karl G.; (Dubuque, IA) ; Nichols;
Boyd M.; (Dubuque, IA) ; Chesterman; John M.;
(Dubuque, IA) ; Starkey; Carl R.; (Dewitt,
IA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Montocchio; Joseph M.
Didelot; David R.
Heine; Karl G.
Nichols; Boyd M.
Chesterman; John M.
Starkey; Carl R. |
Dubuque
Asbury
Dubuque
Dubuque
Dubuque
Dewitt |
IA
IA
IA
IA
IA
IA |
US
US
US
US
US
US |
|
|
Family ID: |
48608928 |
Appl. No.: |
13/328142 |
Filed: |
December 16, 2011 |
Current U.S.
Class: |
165/121 |
Current CPC
Class: |
B60K 11/04 20130101;
B60Y 2200/417 20130101 |
Class at
Publication: |
165/121 |
International
Class: |
F28F 13/00 20060101
F28F013/00 |
Claims
1. A cooling system for a machine, comprising: a first cooling
package comprising a first fan and at least one heat exchanger to
cool at least one fluid associated with the machine, the first fan
configured to rotate in a cooling direction and an opposite
cleaning direction, a second cooling package comprising a second
fan and at least one heat exchanger to cool at least one fluid
associated with the machine, the second fan configured to rotate in
a cooling direction and an opposite cleaning direction, and a fan
control system configured to alternate the first and second fans
between a first cleaning mode and a second cleaning mode, wherein,
in the first cleaning mode the first and second fans concurrently
rotate respectively in their cleaning and cooling directions
advancing air in a first flow direction from the first fan to the
second fan past the at least one heat exchanger of each of the
first and second cooling packages, and, in the second cleaning mode
the first and second fans concurrently rotate respectively in their
cooling and cleaning directions advancing air in a second flow
direction opposite the first flow direction from the second fan to
the first fan past the at least one heat exchanger of each of the
first and second cooling packages.
2. The cooling system of claim 1, wherein the fan control system is
configured to alternate successively the first and second fans
between the first cleaning mode and the second cleaning mode during
an exchanger-cleaning event.
3. The cooling system of claim 1, wherein in the first cleaning
mode the fan control system is configured to command operation of
the first fan at at least a predetermined reverse speed threshold
for a predetermined period of time, and in the second cleaning mode
the fan control system is configured to command operation of the
second fan at at least the predetermined reverse speed threshold
for the predetermined period of time.
4. The cooling system of claim 3, wherein in each of the first and
second cleaning modes the predetermined period of time is
cumulative excluding time that the respective first or second fan
spends below the predetermined reverse speed threshold.
5. The cooling system of claim 3, wherein the fan control system is
configured to abort reversal of the first fan upon occurrence of an
abort event, and is configured to begin reversal of the second fan
when a speed of the first fan reaches a zero fan speed or at the
end of a predetermined period of abort time if the speed of the
first fan is below a low-speed threshold.
6. The cooling system of claim 1, wherein the fan control system is
configured to alternate successive exchanger-cleaning events
between the first cleaning mode and the second cleaning mode.
7. The cooling system of claim 1, wherein the fan control system is
configured to operate the first and second fans sequentially in the
first cleaning mode, an interim cleaning mode, and the second
cleaning mode during an exchanger-cleaning event, and, in the
interim cleaning mode, the first and second fans concurrently
rotate respectively in their cleaning directions.
8. A machine comprising the cooling system of claim 1, wherein the
first and second cooling packages are positioned on laterally
opposite sides of a fore-aft axis of the machine such that the
first and second flow directions are laterally opposite to one
another.
9. The machine of claim 8, wherein the at least one heat exchanger
of the first cooling package and the at least one heat exchanger of
the second cooling package are positioned laterally between the
first and second fans.
10. The machine of claim 9, wherein the machine is a work vehicle.
Description
FIELD OF THE DISCLOSURE
[0001] The present disclosure relates to a cooling system for
cooling one or more fluids of a machine.
BACKGROUND OF THE DISCLOSURE
[0002] Exhaust emissions standards are becoming more stringent.
Such standards have placed an increased heat-rejection demand on
cooling systems of off-highway equipment.
[0003] Vehicles use a cooling system to cool the engine, retarder,
transmission, brakes, and air-conditioner condenser. The coolers of
the cooling system get dirty over a period of use and, in at least
some cases, receive manual cleaning by blowing them with an air
gun. This maintenance process takes time and gets more difficult to
perform if the dirt is left to accrue. It also adds to the time
that the vehicle is unproductive. If left unattended, the vehicle
will start to overheat and lose performance and eventually could
fail one of the major components.
SUMMARY OF THE DISCLOSURE
[0004] According to the present disclosure, a cooling system
comprises a first cooling package, a second cooling package, and a
fan control system. The first cooling package comprises a first fan
and at least one heat exchanger to cool at least one fluid
associated with the machine. The first fan is configured to rotate
in a cooling direction and an opposite cleaning direction. The
second cooling package comprises a second fan and at least one heat
exchanger to cool at least one fluid associated with the machine.
The second fan is configured to rotate in a cooling direction and
an opposite cleaning direction. The fan control system is
configured to alternate the first and second fans between a first
cleaning mode and a second cleaning mode.
[0005] In the first cleaning mode, the first and second fans
concurrently rotate respectively in their cleaning and cooling
directions advancing air in a first flow direction from the first
fan to the second fan past the at least one heat exchanger of each
of the first and second cooling packages. In the second cleaning
mode the first and second fans concurrently rotate respectively in
their cooling and cleaning directions advancing air in a second
flow direction opposite the first flow direction from the second
fan to the first fan past the at least one heat exchanger of each
of the first and second cooling packages.
[0006] In an embodiment, the fan control system is configured to
alternate successively the first and second fans between the first
cleaning mode and the second cleaning mode during an
exchanger-cleaning event. Successive alternation between the first
and second cleaning modes promotes cleaning of the heat exchangers
of foreign material (dirt, debris, etc.).
[0007] In another embodiment, during an exchanger-cleaning event,
the fan control system is configured to operate the first and
second fans sequentially in the first cleaning mode, an interim
cleaning mode, and the second cleaning mode. In the interim
cleaning mode, the first and second fans concurrently rotate
respectively in their cleaning directions, promoting removal of
debris from the compartment in which the heat exchangers are
positioned.
[0008] In yet another embodiment, the fan control system is
configured to alternate successive exchanger-cleaning events
between the first cleaning mode and the second cleaning mode, with
an exchanger-cooling event in a cooling mode therebetween. Such
operation promotes fuel efficiency.
[0009] The above and other features will become apparent from the
following description and the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The detailed description of the drawing refers to the
accompanying figures in which:
[0011] FIG. 1 is a simplified top view showing advancement of air
by a pair of fans during a cooling mode in which the fans operate
in their cooling or forward directions;
[0012] FIG. 2 is a simplified top view showing advancement of air
during a first cleaning mode in which the first fan (e.g., left
side of drawing) operates in its cleaning or reverse direction as
the "reverse fan" and the second fan (e.g., right side of drawing)
operates in its cooling or forward direction as the "forward
fan";
[0013] FIG. 3 is a simplified top view showing advancement of air
during a second cleaning mode in which the first fan operates in
its cooling or forward direction as the forward fan and the second
fan operates in its cleaning or reverse direction as the reverse
fan;
[0014] FIG. 4 is a simplified top view showing advancement of air
during an interim mode in which each of the first and second fans
operates in its cleaning or reverse direction as a reverse fan;
[0015] FIG. 5 is a simplified schematic view of a fan control
system;
[0016] FIG. 6 is a first control routine that cycles the fans
between the first and second cleaning modes during an
exchanger-cleaning event;
[0017] FIG. 7 is an alternative embodiment of the first control
routine adding an interim step in which both fans are reversed
simultaneously between the first and second cleaning modes to
promote debris removal;
[0018] FIG. 8 is a second control routine in which successive
exchanger-cleaning events alternate between the first and second
cleaning modes, with an exchanger-cooling event in a cooling mode
therebetween; and
[0019] FIG. 9 is a chart showing sequential reversal of the fans in
an exchanger-cleaning event.
DETAILED DESCRIPTION OF THE DRAWINGS
[0020] Referring to FIG. 1, there is shown a machine 10 which may
take the form of, for example, an articulated dump truck or other
work vehicle having a fore-aft axis 11. Exemplarily, as an
articulated dump truck, the machine 10 has a front section 12 and a
rear section, the front and rear sections being articulated to one
another and positioned along the fore-aft axis 11. The front
section 12 has the operator's station and an engine compartment 18
in front of the operator's station. The rear section has a tippable
dump body configured to carry a payload.
[0021] The machine 10 has a cooling system 22 for cooling a number
of fluids of the machine 10. The cooling system 22 has a first
cooling package 24, a second cooling package 26, and a fan control
system 28.
[0022] The first cooling package 24 has a first fan 30 and at least
one heat exchanger 32 to cool at least one fluid associated with
the machine 10. The first fan 30 is configured to rotate in a
cooling or forward direction 34-1 and an opposite cleaning or
reverse direction 34-2.
[0023] The second cooling package 26 has a second fan 36 and at
least one heat exchanger 38 to cool at least one fluid associated
with the machine 10. The second fan 36 is configured to rotate in a
cooling or forward direction 40-1 and an opposite cleaning or
reverse direction 40-2.
[0024] The fan control system 28 is configured to operate the first
and second fans 30, 36 in a cooling mode to cool one or more fluids
of the machine 10 during an exchanger-cooling event and in one or
more cleaning modes to clean the at least one heat exchanger 32, 38
of each of the first and second cooling packages 24, 26 during an
exchanger-cleaning event. Referring to FIG. 1, in the cooling mode,
the first and second fans 30, 36 concurrently rotate respectively
in their cooling directions 34-1, 40-1 advancing air from a common
air inlet respectively past the first and second cooling packages
24, 26 to the first and second fans 30, 36 and out respective air
outlets.
[0025] The fan control system 28 is configured to alternate
successively the first and second fans 30, 36 between a first
cleaning mode and a second cleaning mode during an
exchanger-cleaning event. Referring to FIG. 2, in the first
cleaning mode the first and second fans 30, 36 concurrently rotate
respectively in their cleaning and cooling directions 34-2, 40-1
advancing air in a first flow direction 42 from the first fan 30 to
the second fan 36 past the at least one heat exchanger 32, 38 of
each of the first and second cooling packages 24, 26. Referring to
FIG. 3, in the second cleaning mode the first and second fans 30,
36 concurrently rotate respectively in their cooling and cleaning
directions 34-1, 40-2 advancing air in a second flow direction 44
opposite the first flow direction 42 from the second fan 36 to the
first fan 30 past the at least one heat exchanger 32, 38 of each of
the first and second cooling packages 24, 26.
[0026] The fan control system 28 is configured to cycle the first
and second fans 30, 36 between the first and second cleaning modes
for one or more cycles during the exchanger-cleaning event. For
example, the fan control system 28 is configured to cycle the fans
30, 36 between the first and second cleaning modes for one cycle
during the exchanger-cleaning event.
[0027] Exemplarily, the first and second cooling packages 24, 26
are positioned on laterally opposite sides of a fore-aft axis 11 of
the machine 10 such that the first and second flow directions 42,
44 are laterally opposite to one another. The first cooling package
24 may be positioned on the right-hand side of the axis 11, and the
second cooling package 26 may be positioned on the left-hand side
of the axis 11. The at least one heat exchanger 32 of the first
cooling package 24 and the at least one heat exchanger 38 of the
second cooling package 26 are positioned laterally between the
first and second fans 30, 36. Exemplarily, an internal combustion
engine 48 (e.g., diesel engine) is positioned laterally between the
first and second cooling packages 24, 26.
[0028] Each of the first and second cooling packages 24, 26 may
have a number of heat exchangers. Exemplarily, the first cooling
package 24 has three units of one or more heat exchangers 32
stacked laterally relative to one another, with a laterally outward
unit, a laterally inward unit, and a laterally intermediate unit
positioned laterally between the laterally outward and inward
units. The laterally outward unit is positioned laterally between
the first fan 30 and the laterally intermediate unit. The laterally
inward unit is positioned laterally between the laterally
intermediate unit and the engine 48. The laterally outward unit is
a radiator 32-1 configured to cool engine coolant. The laterally
intermediate unit is a combination cooler having, from rear to
front, a transmission-and-retarder oil cooler 32-2 configured to
cool oil of the transmission and retarder and a hydraulic oil
cooler 32-3 configured to cool hydraulic oil. The
transmission-and-retarder oil cooler and the hydraulic oil cooler
are adjacent to one another and are fastened to another (e.g.,
using bolts and nuts). The laterally inward unit is a fuel cooler
32-4 configured to cool fuel. The first cooling package 24 may be
configured in any suitable fashion (e.g., the number, size, use,
layout, etc. of heat exchangers may be different for a given
machine).
[0029] Exemplarily, the second cooling package 26 has two units of
one or more heat exchangers 38 stacked laterally relative to one
another, with a laterally outward unit, a laterally inward unit,
and a laterally intermediate unit positioned laterally between the
laterally outward and inward units. The laterally outward unit is
positioned laterally between the second fan 36 and the laterally
intermediate unit. The laterally inward unit is positioned
laterally between the laterally outward unit and the engine 48. The
laterally outward unit is a radiator 38-1 configured to cool engine
coolant. The laterally intermediate unit is a combination cooler
having, from rear to front, a first brake cooler 38-2 configured to
cool an axle and associated brakes (e.g., the middle axle of an
articulated dump truck, a second brake cooler 38-3 configured to
cool an axle and associated brakes (e.g., the front axle of an
articulated dump truck), and a charge-air cooler 38-4 configured to
cool pressurized engine intake air. The second brake cooler is
positioned between the first brake cooler and the air conditioner
condenser and is fastened to them (e.g., using bolts and nuts). The
laterally inward unit is an air-conditioning condenser 38-5. The
second cooling package 26 may be configured in any suitable fashion
(e.g., the number, size, use, layout, etc. of heat exchangers may
be different for a given machine).
[0030] Exemplarily, the two radiators 32-1, 38-1 of the first and
second cooling packages 24, 26 are flow-parallel to one another. In
such a case, a first node is coupled fluidly to a coolant outlet of
the engine 48 and respective coolant inlets of the two radiators,
and a second node is coupled fluidly to respective coolant outlets
of the two radiators and a coolant inlet of the engine 48.
[0031] Referring to FIG. 5, the fan control system 28 may be
configured in any suitable manner to control operation of the fans
30, 36. Exemplarily, the fan control system 28 has a first
electro-hydraulic system 68 for the first fan 30 and a second
electro-hydraulic system 69 for the second fan 36, the systems 68,
69 sharing a hydraulic fluid reservoir tank. Each electro-hydraulic
system 68, 69 has a variable displacement hydraulic pump 70 and a
hydraulic motor 72. The motor 72 is coupled mechanically to the
respective fan 30, 36 to drive that fan in either direction. The
pump 70 is coupled hydraulically to the respective motor 72 to
drive that motor 72, and may be, for example, an axial-piston pump.
The first electro-hydraulic system 68 has a displacement control
mechanism that provides pressure-compensated, load-sense (LS)
control of the pump 70 (e.g., of the swash plate of the pump 70).
The displacement of the pump 70 of the second electro-hydraulic
system 69 is electronically controlled using a displacement control
mechanism discussed below. The controller 58 is coupled
electrically to a speed sensor (e.g., Hall-effect sensor with 12
pulses per revolution) in each motor 72 to receive information
indicative of the rotational speed of the respective fan 30, 36 in
order to control such speed.
[0032] Each electro-hydraulic system 68, 69 has a directional
control valve 74, a reverse valve 76, and a speed valve 78. The
directional control valve 74 is configured to direct hydraulic
fluid selectively to either of two work ports of the motor 72 to
control the direction of rotation of the motor 72. The reverse
valve 76 is configured as an on/off valve and is coupled
electrically to an electric first controller 58 of the machine 10
(e.g., chassis control unit) so as to be under the control of the
controller 58. The reverse valve 76 is coupled hydraulically to the
pump 70 and a pilot port of the directional control valve 74 to
direct supply pressure to the pilot port of the directional control
valve 74 when the solenoid of the reverse valve 76 is energized by
the controller 58. Energizing and de-energizing the reverse valve
74 causes the spool of the directional control valve 74 to shift
accordingly to change the direction of flow to the motor 72 and
thus the direction of rotation of the respective fan 30, 36.
[0033] An intermediate, transition section of the directional
control valve 74 is configured to couple fluidly the two work ports
of the motor 72 through the valve 74 momentarily allowing the
respective fan 30, 36 to freewheel during shifting of the spool
between a first position directing hydraulic fluid to a first work
port of the motor 72 and a second position directing hydraulic
fluid to a second work port of the motor 72. Such a work port
connection promotes motor life by avoiding a sudden deadhead of the
motor 72 that might otherwise occur in the absence of the
transition section.
[0034] Each electro-hydraulic system 68, 69 has a first
pressure-relief valve 77 and a second pressure-relief valve 79. The
first pressure-relief valve 77 is coupled fluidly to the pressure
supply line from the respective pump 52 and a return line to tank.
The second pressure-relief valve 79 is coupled fluidly to either
side of the first pressure-relief valve 77 in parallel thereto, and
has a pressure-relief setting lower than that of the valve 77. The
second pressure-relief valve 77 is coupled electrically to the
first controller 58 so as to be under the control of that
controller 58. When the controller 58 energizes the solenoid of the
reverse valve 76, it energizes the solenoid of the second
pressure-relief valve 79 momentarily so as to relieve pressure in
the pressure supply line as the spool of the directional control
valve 74 passes through its intermediate, transition section,
avoiding transmission of a pressure spike to upstream components
with respect to the first electro-hydraulic system 68 and to the
pump 70 with respect to the second electro-hydraulic system 69.
[0035] The speed valve 78 of the first electro-hydraulic system 68
is configured, for example, as a proportional load-sense relief
valve and is operable to vary the speed of rotation of the fan 30.
The speed valve 78 is coupled electrically to the controller 58 so
as to be under the control of the controller 58 (e.g., by
pulse-width modulation or "PWM" such as, for example, PWM to ground
with system voltage to high side of valve 78 in response to vehicle
start-up). The controller 58 is configured to command the speed
valve 78 to open by energizing its solenoid in order to bleed
hydraulic fluid from an associated load sense line LS1 so as to
slow the fan speed. De-energizing the solenoid of the speed valve
78 increases the fan speed.
[0036] The speed valve 78 of the second electro-hydraulic system 69
is configured, for example, as a proportional valve and is included
in the displacement control mechanism for the pump 70 of the system
69. The displacement control mechanism has a hydraulic first
cylinder 86 and a hydraulic second cylinder 88, both cylinders 86,
88 coupled to the displacement control of the pump 70 (e.g., swash
plate). The speed valve 78 has two work ports coupled fluidly
respectively to the first cylinder 86 and the second cylinder 88.
The speed valve 78 is spring-biased to route hydraulic fluid from
the supply line to the first cylinder 86 so as to displace the pump
70 fully for maximum speed of the second fan 36. The speed valve 78
is coupled electrically to the controller 58 so as to be under the
control of the controller 58 (e.g., by pulse-width modulation or
"PWM" such as, for example, PWM to ground with system voltage to
high side of valve 78 in response to vehicle start-up). The
controller 58 is configured to command the speed valve 78 to shift
by energizing its solenoid in order to route hydraulic fluid from
the supply line to the second cylinder 88 so as to slow the second
fan 36. De-energizing the solenoid of the speed valve 78 increases
the fan speed.
[0037] Each pump 70 can be a pump dedicated to the respective fan
30, 36, or it may be shared with other functions. Exemplarily, the
pump 70 of the second electro-hydraulic system 69 is dedicated to
the second fan 36, whereas the pump 70 of the first
electro-hydraulic system 68 is shared with other functions (e.g.,
steering, brake, axle cooling, dump body tip, suspension) and, as
such, may be the main hydraulic pump of the machine 10. In such a
case, the pump 70 of the first electro-hydraulic system 68 may be
driven off of the transmission, coupled to the engine 48, and the
pump 70 of the second electro-hydraulic system 69 may be driven off
the engine 48 (e.g., mounted directly to the engine 48) with a gear
pump exemplarily stacked behind it.
[0038] For simplification, with respect to the first
electro-hydraulic system 68, components between the "shared" pump
70 and the motor 72 associated with the fan 30 are shown, although
the other functions are not shown. Such components include an
attenuator 80, a priority valve 81, an electro-hydraulic cut-off
valve 82, and a compensator valve 84. The attenuator 80 attenuates
noise due, for example, to pressure pulsation from the pump 70 of
the first electro-hydraulic system 68. The priority valve 81
establishes priority flow for steering (and also for brakes but
mainly for steering). The cut-off valve 82 is closed during tipping
of the dump body of the machine 10 to decrease the time that it
takes to tip the dump body in response to a signal from the first
controller 58 due to movement of the dump body (e.g., caused by
displacement of the dump lever or actuation of a dump body-up
button or a dump body-down button). The compensator valve 84
regulates the pressure supplied to the motor 72 to be that which is
commanded of the speed valve 78 (e.g., if the load-sense system
causes the pump 70 to output a pressure greater than what is needed
for the fan 30, the compensator valve 84 will reduce that pressure
to the pressure called for by the speed valve 78). The load-sense
system for the "shared" pump 70 is identified as "LS1" in FIG. 5,
and exemplarily includes a network of shuttle valves associated
with various functions to establish the load-sense signal back to
the pump control. A system pressure-relief unit 89 is positioned in
the system 68 ahead of the function(s) of the system 68.
[0039] Referring to FIG. 6, there is shown a flowchart of a control
routine 110 for cleaning the heat exchangers 32, 38 of the first
and second cooling packages 24, 26 in the cleaning mode. The
cleaning mode may be initiated automatically or manually by the
operator. Automatic initiation occurs in step 112, and manual
initiation occurs in step 114.
[0040] In step 112, the electric first controller 58 of the control
system 28 (e.g., the chassis control unit) monitors elapsed time
(t) since the end of the last cleaning event of the cooling
packages 24, 26, and determines if a predetermined period of time
(.DELTA.t) has elapsed since the end of that event. A timer 62
tracks such elapsed time, and is included in the controller 58, or
may be a stand-alone device or part of another controller. The
predetermined period of time may be selected by the operator
through, for example, a display monitor at the operator's station
(e.g., 1/2 hour, 1 hour, 2 hours, 3 hours, 4 hours), or it may be a
default value (e.g., 4 hours). If the predetermined period of time
has elapsed, the routine 110 advances to step 116. If no, the
controller 58 continues to monitor elapsed time since the last
exchanger-cleaning event.
[0041] In step 114, an operator or other person can manually
request activation of the cleaning mode through a display monitor
at the operator's station. If a manual request has been received,
the routine 110 advances to step 116.
[0042] In step 116, the controller 58 determines whether any of a
number of inhibit conditions is present. The conditions monitored
may include, for example: the temperature of any of the fluids in
the heat exchangers of the cooling packages 24, 26 is at or above
its respective maximum allowable temperature (since a cleaning
event will reduce cooling); the windshield wipers are off (since
wiper activation is indicative of rain which could cause a cloud of
dust discharged from the machine 10 during cleaning to stick to
windows of the operator's station); and a diesel particulate filter
is being regenerated (e.g., based on a CAN message received by the
controller 58 from an electric second controller 60 such as an
engine control unit). The controller 58 receives inputs indicative
of whether any such inhibit condition exists. If the controller 58
determines that an inhibit condition exists, the controller 58
waits to activate the cleaning mode until such condition
terminates. If a manual request for cleaning was received, the
controller 58 may initiate activation of an alert (e.g., on the
display monitor) indicating that the cleaning mode is inhibited. If
no inhibit condition exists, the routine 110 advances to step
118.
[0043] Other inhibit conditions may include, for example, one or
more of the following: engine speed is not greater than a threshold
engine speed (e.g., 1400 rpm), since lower engine speeds may not
provide sufficient hydraulic flow to reach maximum fan speed (in
other words, engine speeds greater than 1400 rpm may provide
sufficient hydraulic flow to reach maximum fan speed; it is thought
that engine idle speed may even be sufficient); and ground speed of
the machine 10 is greater than a threshold ground speed (e.g., 5
miles per hour), so as to reduce the likelihood that a person is in
the path of discharge.
[0044] In step 118, the controller 58 activates an
exchanger-cleaning event in which the controller 58 alternates
successively the first and second fans 30, 36 between the first
cleaning mode and the second cleaning mode. Such alternating
succession may occur for one or more cycles (e.g., one cycle).
During each cycle, the first cleaning mode is performed followed by
performance of the second cleaning mode.
[0045] In step 118-1 of step 118, the controller 58 activates the
first cleaning mode. In the first cleaning mode, the first and
second fans 30, 36 concurrently rotate respectively in their
cleaning and cooling directions 34-2, 40-1 advancing air in a first
flow direction 42 laterally relative to the fore-aft axis 11 from
the first fan 30 to the second fan 36 past the at least one heat
exchanger 32, 38 of each of the first and second cooling packages
24, 26.
[0046] Referring to FIG. 9, to reverse the first fan 30 from its
cooling direction to its cleaning direction, in time T1, the
controller 58 commands operation of the speed valve 78 associated
with the first fan 30 (gradually energizes its solenoid) (i.e., the
first speed valve 78) to ramp down the speed of the first fan 30 at
a predetermined rate (e.g., 100 rpm/second) toward a zero fan speed
using the speed information from the speed sensor in the first fan
motor 72. Such ramping down helps to avoid fan motor cavitation.
When the fan speed reaches a predetermined fan idle speed (e.g.,
600 rpm), the controller 58 commands operation of the first speed
valve 78 so as to command the first fan 30 to the zero fan speed
(i.e., commands maximum current to the valve 78 assuming no fault
requiring abort), and begins to monitor the fan speed for up to a
predetermined period of time (e.g., 10 seconds) using the speed
information from the speed sensor in the first fan motor 72 (the
controller 58 is unable to control the 100 rpm/second rate below
the fan idle speed). The solenoid of the reverse valve 76
associated with the first fan 30 9 (i.e., the first reverse valve
76) is de-energized during time T1.
[0047] If, during the predetermined period of time, the fan speed
reaches zero, time T2 starts immediately. If, at the end of the
predetermined period of time, the fan speed does not reach zero but
reaches below a low-speed threshold (e.g., 100 rpm), time T2 starts
at the end of the predetermined period of time. If neither
condition occurs, the controller 58 aborts reversal of the first
fan 30, and begins reversal of the second fan 36 (i.e., advances
the second fan 36 from T1-T7). As for the first fan 30, the
controller 58 commands operation of the first speed valve 78
(gradually decreases its current) to ramp up the speed of the first
fan 30 at a predetermined rate (e.g., 100 rpm/second) to a variable
forward speed based on the cooling need of the first cooling
package 24 using the speed information from the speed sensor in the
first fan motor 72.
[0048] In time T2, the controller 58 commands operation of the
first speed valve 78 so as to command the first fan 30 to the zero
fan speed (i.e., commands maximum current to the valve 78 assuming
no fault requiring abort), and monitors the fan speed of the first
fan 30 for a predetermined period of time using the speed
information from the speed sensor in the first fan motor 72 to
confirm if the fan speed remains below the low-speed threshold. The
predetermined period of time may be between a few milliseconds and
a few seconds. It may be, for example, 10 milliseconds or,
preferably, two seconds to ensure that the fan speed has indeed
reduced to a desired level for changing its direction of rotation
since the speed sensor does not indicate direction of rotation. If,
during the predetermined period of time, the fan speed of the first
fan 30 is equal to or greater than the low-speed threshold, the
controller 58 aborts reversal of the first fan 30 and begins
reversal of the second fan 36 (i.e., advances the second fan 36
from T1-T7), and, regarding the first fan 30, the controller 58
commands operation of the first speed valve 78 (gradually decreases
its current) to ramp up the speed of the first fan 30 at a
predetermined rate (e.g., 100 rpm/second) to a variable forward
speed based on the cooling need of the first cooling package 24
using the speed information from the speed sensor in the first fan
motor 72. The solenoid of the first reverse valve 76 is
de-energized during time T2.
[0049] In time T3, the controller 58 energizes the solenoid of the
first reverse valve 76 and commands operation of the first speed
valve 78 (proportionally energizes its solenoid) so as to reverse
the direction of hydraulic flow to the first fan motor 72 and
command the speed of the first fan 30 to a predetermined reverse
speed threshold (e.g., 1600 rpm). The controller 58 monitors the
speed information from the speed sensor in the first fan motor 72
for up to a predetermined amount of time (e.g., two seconds) to
confirm if a non-zero fan speed has been achieved, as there will be
a natural initial system delay (due, for example, to solenoid
saturation, valve hysteresis, and time to measure fan speed). If
the non-zero fan speed has not been achieved within the
predetermined period of time, the controller 58 aborts reversal of
the first fan 30 and begins reversal of the second fan 36 (i.e.,
advances the second fan 36 from T1-T7). During abort of the first
fan 30, the controller 58 de-energizes the solenoid of the first
reverse valve 76 and commands operation of the first speed valve 78
(gradually decreases its current) to ramp up the speed of the first
fan 30 at a predetermined rate (e.g., 100 rpm/second) to a variable
forward speed based on the cooling need of the first cooling
package 24 using the speed information from the speed sensor in the
first fan motor 72.
[0050] Time T4 begins when the controller 58 determines that the
first fan 30 has achieved a non-zero fan speed using the speed
information from the speed sensor in the first fan motor 72. In
time T4, the controller 58 continues to energize the solenoid of
the first reverse valve 76 and to energize proportionally the
solenoid of the first speed valve 78 so as to command the
predetermined reverse speed threshold, and monitors the fan speed
for up to a predetermined period of time (e.g., four seconds) to
confirm if the predetermined reverse speed threshold has been
achieved. If the predetermined reverse speed threshold has not been
achieved in the predetermined period of time, the controller 58
aborts reversal of the first fan 30, and begins reversal of the
second fan 36 (i.e., advances the second fan 36 from T1-T7).
[0051] To abort reversal of the first fan 30 in time T4, the
controller 58 commands operation of the first speed valve 78 so as
to command the first fan 30 to a zero fan speed (i.e., commands
maximum current to the valve 78 assuming no fault requiring machine
shutdown and restart so as to de-energize the valve 78 thereby
resetting it in case the second speed valve 78 is malfunctioning)
and monitors the fan speed for up to a predetermined period of time
(e.g., 10 seconds) using the speed information from the speed
sensor in the first fan motor 72. If, during the predetermined
period of time, the fan speed reaches zero, or, at the end of the
predetermined period of time, the fan speed is at least below the
low-speed threshold, the controller 58 continues to command the
zero fan speed for another predetermined period of time (e.g., two
seconds), in response to elapse of which the controller 58
de-energizes the solenoid of the first reverse valve 76 and
commands operation of the first speed valve 78 (gradually decreases
its current) to ramp up the speed of the first fan 30 at a
predetermined rate (e.g., 100 rpm/second) to a variable forward
speed based on the cooling need of the first cooling package 24
using the speed information from the speed sensor in the first fan
motor 72. The controller 58 begins reversal of the second fan 36
when the speed of the first fan 30 drops below the low-speed
threshold (i.e., advances the second fan 36 from T1-T7).
[0052] When the predetermined reverse speed threshold is reached,
time T5 begins, in which the controller 58 continues to energize
the solenoid of the first reverse valve 76 and to energize the
solenoid of the first speed valve 78 so as to command the speed of
the first fan 30 to be the reverse speed threshold for a
predetermined period of reverse time. That predetermined period of
time may be, for example, 30 seconds, or, in the case of worksites
with excessive debris, 60 seconds. Such period of time may be
selectable by the operator via a display monitor in the operator's
station. Once the fan speed reaches the reverse speed threshold,
the controller 58 starts counting the amount of reverse time in
which the first fan 30 is at or above the reverse speed threshold.
If the fan speed drops below the threshold, the controller 58 stops
counting the reverse time. Instead, the controller 58 starts
counting the amount of time below the threshold. As such, when the
fan speed is at or above the threshold, time is accrued toward the
predetermined period of reverse time, whereas, when the fan speed
is below the threshold, time is accrued toward a predetermined
period of fault time which may be, for example, 30 seconds. The
reverse time and the fault time are thus both cumulative. If the
reverse time is reached before the fault time is reached, the
controller 58 proceeds to time T6. If the fault time is reached
before the reverse time is reached, the controller 58 aborts
reversal of the first fan 30, and begins reversal of the second fan
36. The abort sequence in time T5 is the same as the abort sequence
in T4.
[0053] In time T6, the controller 58 commands operation of the
first speed valve 78 to command the speed of the first fan 30 to
zero (i.e., commands maximum current to the valve 78 assuming no
fault requiring abort), at an uncontrolled rate. Since this speed
decrease is uncontrolled (the first fan 30 freewheels), the
controller 58 monitors the fan speed for up to a predetermined
period of time (e.g., 10 seconds) using the speed information from
the speed sensor in the first fan motor 72. If, during the
predetermined period of time, the fan speed reaches zero, time T7
starts immediately. If, at the end of the predetermined period of
time, the fan speed does not reach zero but reaches below the
low-speed threshold (e.g., 100 rpm), time T7 starts at the end of
the predetermined period of time. If neither condition occurs, the
controller 58 aborts the exchanger-cleaning event altogether in
order to avoid reversing both fans 30, 36 at the same time, and may
therefore require the machine 10 to be shut down and re-started
(e.g., so as to de-energize the second speed valve 78 thereby
resetting it in case the second speed valve 78 is
malfunctioning).
[0054] In time T7, the controller 58 commands operation of the
first speed valve 78 so as to command the first fan 30 to the zero
fan speed (i.e., commands maximum current to the valve 78 assuming
no fault requiring abort), and monitors the fan speed of the first
fan 30 for a predetermined period of time using the speed
information from the speed sensor in the first fan motor 72 to
confirm if the fan speed remains below the low-speed threshold. The
predetermined amount of time may be between a few milliseconds and
a few seconds. It may be, for example, 10 milliseconds or,
preferably, two seconds to ensure that the fan speed has indeed
reduced to a desired level for changing its direction of rotation
since the speed sensor does not indicate direction of rotation. If
the fan speed remains below the low-speed threshold for the
predetermined period of time, at the end of T7, the controller 58
de-energizes the solenoid of the first reverse valve 76 and
commands operation of the first speed valve 78 (gradually decreases
its current) to ramp up the speed of the first fan 30 at a
predetermined rate (e.g., 100 rpm/second) to a variable forward
speed based on the cooling need of the first cooling package 24
using the speed information from the speed sensor in the first fan
motor 72. If the fan speed does not remain below the low-speed
threshold, the controller 58 aborts the exchanger-cleaning event
altogether in order to avoid reversing both fans 30, 36 at the same
time, and may therefore require the machine 10 to be shut down and
re-started (e.g., so as to de-energize the second speed valve 78
thereby resetting it in case the second speed valve 78 is
malfunctioning).
[0055] The routine 110 advances to step 118-2 of step 118 as soon
as the zero fan speed of the first fan 30 has been achieved in T6
or if the fan speed of the first fan 30 is below the low-speed
threshold at the end of the predetermined period of time of T6. In
step 118-2, the controller 58 activates the second cleaning mode,
while concluding the first cleaning mode by advancing the first fan
30 through T7 and ramping its fan speed to a forward speed.
[0056] In the second cleaning mode, the first and second fans 30,
36 concurrently rotate respectively in their cooling and cleaning
directions 34-1, 40-2 advancing air in a second flow direction 44
opposite the first flow direction 42 laterally relative to the
fore-aft axis 11 from the second fan 36 to the first fan 30 past
the at least one heat exchanger 32, 38 of each of the first and
second cooling packages 24, 26. To do so, the controller 58
reverses the second fan 36 according to the reversal sequence
(i.e., T1-T7) described above for the first fan 30 in the first
cleaning mode 118-1 and aborts in the same manner if necessary,
except that, in the event of an abort of reversal of the second fan
36 in any of T1-T5, the controller 58 aborts the exchanger-cleaning
event altogether (i.e., does not reverse the first fan 30 since the
first fan 30 would have already been reversed). With respect to the
second cleaning mode, the speed valve 78 associated with the second
fan 36 (second speed valve 78) and the reverse valve 76 associated
with the second fan 36 (second reverse valve 76) are involved. In
the event of an abort during T6 or T7, the controller 58 aborts the
exchanger-cleaning event altogether, and may therefore require the
machine 10 to be shut down and re-started (e.g., so as to
de-energize the second speed valve 78 thereby resetting it in case
the second speed valve 78 is malfunctioning).
[0057] When finished with the reversal sequence for the second fan
36 (i.e., T1-T7), the control routine 110 advances to step 120 so
as to resume the cooling mode. In step 120, if the fan speed
remains below the low-speed threshold for the predetermined period
of time, at the end of T7, the controller 58 de-energizes the
second reverse valve 76 and commands operation of the second speed
valve 78 (gradually decreases its current) to ramp up the speed of
the second fan 36 at a predetermined rate (e.g., 100 rpm/second) to
a variable forward speed based on the cooling need of the second
cooling package 26 using the speed information from the speed
sensor in the second fan motor 72. As alluded to above, if the fan
speed does not remain below the low-speed threshold, the controller
58 aborts the exchanger-cleaning event altogether, and may
therefore require the machine 10 to be shut down and re-started
(e.g., so as to de-energize the second speed valve 78 thereby
resetting it in case the second speed valve 78 is
malfunctioning).
[0058] During reversal of the first fan 30, the controller 58
commands operation of the second fan 36 at a forward speed based on
the cooling need of the cooling package 26 through de-energization
of the second reverse valve 76 and proportional control of the
second speed valve 78. An electric second controller 60 (e.g.,
engine control unit coupled electrically to the first controller 58
via a controller area network, i.e., CAN) determines the fan speed
of the second fan 36 based on the cooling need of the fluid of the
second cooling package 26 closest to its upper temperature limit
(alternatively, the electric first controller 58 could perform this
function). Exemplarily, the second controller 60 receives the
engine coolant temperature from a temperature sensor, and sends
this value to the first controller 58 for determination of whether
an inhibit condition exists. The second controller 60 sends that
fan speed to the electric first controller 58 which controls the
second speed valve 78 so as to operate the second fan 36 at that
fan speed. The first fan 30 is operated in a corresponding manner
during reversal of the second fan 36.
[0059] Referring to FIGS. 4 and 7, an alternative embodiment of the
step 118 is shown as step 218, and includes an interim step 218-3
due to overlap of activation of the first and second cleaning modes
in steps 218-1 and 218-2, respectively. In step 218-3, the
controller 58 commands operation of the fans 30, 36 such that the
fans 30, 36 concurrently rotate respectively in their cleaning
directions for an interim predetermined period of time so as to
blow air inwardly toward the engine 48 to cause debris to blow out
any openings in the compartment 18 (e.g., any openings between
panels, and front grill).
[0060] To do so, in step 218-2, the controller 58 activates the
first cleaning mode, advancing the first fan 30 in sequence from T1
to T5, while the second fan 36 continues to operate at a variable
fan cooling speed. While the first fan 30 is still in T5 or
immediately afterwards during which the controller 58 keeps the
first fan 30 at the predetermined reverse speed threshold (e.g.,
1600 rpm), the controller 58 activates the second cleaning mode
reversing the second fan 36 from its cooling direction to its
cleaning direction by advancing it in sequence through T1, T2, T3,
and T4 to the predetermined reverse speed threshold. The controller
58 keeps the fan speed of the fans 30, 36 at the predetermined
reverse speed threshold for an interim predetermined period of time
(e.g., 10 seconds). Upon elapse of the interim predetermined period
of time, the controller 58 concludes the first cleaning mode,
advancing the first fan 30 in sequence through T6 and T7, after
which it commands the first fan 30 to a variable forward speed
(assuming no abort). It subsequently concludes the second cleaning
mode, advancing the second fan 36 in sequence through T5, T6, and
T7, after which it commands the second fan 36 to a variable forward
speed (assuming no abort).
[0061] Thus, the controller 58 may be configured to operate the
first and second fans 30, 36 sequentially in the first cleaning
mode, the interim cleaning mode, and the second cleaning mode
during an exchanger-cleaning event, with the first and second
cleaning modes overlapping to provide the interim cleaning
mode.
[0062] Referring to FIG. 8, a control routine 310 provides an
alternative embodiment to control routine 110. The control routine
310 alternates between the cooling mode and a cleaning mode, and
the cleaning mode may be activated in any suitable manner such as
by elapse of a predetermined period of time (e.g., step 112) or by
manual request (e.g., step 114), assuming one of the inhibit
conditions is not present (e.g., step 116). In other words, the
routine 310 will perform steps 112, 114, and 116 before performing
a cleaning mode.
[0063] The control routine 310 is different in that each
exchanger-cleaning event involves only one of the first and second
cleaning modes such that successive exchanger-cleaning events
alternate between the first and second cleaning modes. For example,
the control routine 310 may advance from the cooling mode in step
316 to only the first cleaning mode in step 318 (does not include
the second cleaning mode during this exchanger-cleaning event). The
routine 310 may then advance back to the cooling mode in step 320
and then to only the second cleaning mode in step 322 (does not
include the first cleaning mode during this exchanger-cleaning
event). This pattern may continue, promoting fuel economy since
both cleaning modes are not activated during an exchanger-cleaning
event.
[0064] In step 318, the controller 58 operates the first and second
fans 30, 36 in their cleaning and cooling directions, respectively,
in a manner similar to what is discussed in connection with step
118-1 of FIG. 6. In step 320, the controller 58 returns the first
fan 30 to its cooling direction to a variable forward speed based
on cooling need. In step 322, the controller 58 operates the first
and second fans 30, 36 in their cooling and cleaning directions,
respectively, in a manner similar to what is discussed in
connection with step 118-2 of FIG. 6. The routine 310 then advances
back to step 316, in which the controller 58 returns the second fan
36 to its cooling direction to a variable forward speed based on
cooling need. The controller 58 may thus be configured to alternate
successive exchanger-cleaning events between the first cleaning
mode and the second cleaning mode. In the event an abort of the
reversal sequence of either fan 30, 36 is triggered in any of
T1-T7, the controller 58 performs the abort sequence associated
with the respective time period (discussed above in connection with
routine 110 and fan 30) without reversing the other fan, thereby
aborting the exchanger-cleaning event altogether.
[0065] In the control routine 110, it is thought that, during each
of the first and second cleaning modes, about 86 percent of the
debris in the engine compartment 18 is removed from the engine
compartment while about 10 percent remains.
[0066] In the control routines discussed herein, during a cleaning
mode, the forward fan (i.e., the fan operating in its forward
direction) is operated at a variable forward speed based on cooling
needs. Alternatively, the controller 58 may operate the forward fan
at its maximum calibrated operating speed.
[0067] Cooling is more efficient in the cooling mode than any of
the cleaning modes, but also takes place during the
exchanger-cleaning event.
[0068] The cooling system 22 may be used with an articulated
machine (e.g., machine 10) or a non-articulated machine.
[0069] While the disclosure has been illustrated and described in
detail in the drawings and foregoing description, such illustration
and description is to be considered as exemplary and not
restrictive in character, it being understood that illustrative
embodiment(s) have been shown and described and that all changes
and modifications that come within the spirit of the disclosure are
desired to be protected. It will be noted that alternative
embodiments of the present disclosure may not include all of the
features described yet still benefit from at least some of the
advantages of such features. Those of ordinary skill in the art may
readily devise their own implementations that incorporate one or
more of the features of the present disclosure and fall within the
spirit and scope of the present invention as defined by the
appended claims.
* * * * *