瑞典专利SE1251400A1 Cooling system with double reversed fans

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专利摘要:
Attorney Docket No. P20047-US Abstract of the Disclosure A cooling system comprises a first cooling package, a second coolingpackage, and a fan control system. The first cooling package comprises a first fanand at least one heat exchanger to cool at least one fluid associated with themachine. The first fan is configured to rotate in a cooling direction and an oppositecleaning direction. The second cooling package comprises a second fan and atleast one heat exchanger to cool at least one ﬂuid associated with the machine. Thesecond fan is configured to rotate in a cooling direction and an opposite cleaningdirection. The fan control system is configured to alternate the first and second fans between a first cleaning mode and a second cleaning mode. 22
公开号:SE1251400A1
申请号:SE1251400
申请日:2012-12-11
公开日:2013-06-17
发明作者:Joseph M Montocchio；David Didelot；Boyd M Nichols；John M Chesterman；Carl R Starkey；Karl G Heine
申请人:Deere & Co；
IPC主号:

专利说明:

[2] [0002] Exhaust emissions standards are becoming more stringent. Such standardshave placed an increased heat-rejection demand on cooling systems of off-highwayequipment.
[3] [0003] Vehicles use a cooling system to cool the engine, retarder, transmission,brakes, and air-conditioner condenser. The coolers of the cooling system get dirtyover a period of use and, in at least some cases, receive manual cleaning by blowingthem with an air gun. This maintenance process takes time and gets more difficult toperform if the dirt is left to accrue. lt also adds to the time that the vehicle isunproductive. lf left unattended, the vehicle will start to overheat and lose performance and eventually could fail one of the major components.
[4] [0004] According to the present disclosure, a cooling system comprises a firstcooling package, a second cooling package, and a fan control system. The firstcooling package comprises a first fan and at least one heat exchanger to cool atleast one ﬂuid associated with the machine. The ﬁrst fan is configured to rotate in acooling direction and an opposite cleaning direction. The second cooling packagecomprises a second fan and at least one heat exchanger to cool at least one fluidassociated with the machine. The second fan is configured to rotate in a coolingdirection and an opposite cleaning direction. The fan control system is configured toalternate the first and second fans between a first cleaning mode and a secondcleaning mode.
[5] [0005] ln the first cleaning mode, the first and second fans concurrently rotaterespectively in their cleaning and cooling directions advancing air in a first flowdirection from the first fan to the second fan past the at least one heat exchanger ofeach of the first and second cooling packages. ln the second cleaning mode the firstand second fans concurrently rotate respectively in their cooling and cleaning Attorney Docket No. P20047-US directions advancing air in a second flow direction opposite the first flow directionfrom the second fan to the first fan past the at least one heat exchanger of each ofthe first and second cooling packages.
[6] [0006] ln an embodiment, the fan control system is configured to alternatesuccessively the first and second fans between the first cleaning mode and thesecond cleaning mode during an exchanger-cleaning event. Successive alternationbetween the first and second cleaning modes promotes cleaning of the heatexchangers of foreign material (dirt, debris, etc.).
[7] [0007] In another embodiment, during an exchanger-cleaning event, the fan controlsystem is configured to operate the first and second fans sequentially in the firstcleaning mode, an interim cleaning mode, and the second cleaning mode. ln theinterim cleaning mode, the first and second fans concurrently rotate respectively intheir cleaning directions, promoting removal of debris from the compartment in whichthe heat exchangers are positioned.
[8] [0008] ln yet another embodiment, the fan control system is configured to alternatesuccessive exchanger-cleaning events between the first cleaning mode and thesecond cleaning mode, with an exchanger-cooling event in a cooling modetherebetween. Such operation promotes fuel efficiency.
[9] [0009] The above and other features will become apparent from the followingdescription and the attached drawings.
[10] [0010] The detailed description of the drawing refers to the accompanying figures inwhich:
[11] [0011] FIG. 1 is a simplified top view showing advancement of air by a pair of fansduring 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 firstcleaning mode in which the first fan (e.g., left side ofdrawing) operates in itscleaning or reverse direction as the “reverse fan” and the second fan (e.g., right sideof drawing) operates in its cooling or forward direction as the “forward fan”;
[13] [0013] FIG. 3 is a simplified top view showing advancement of air during a secondcleaning mode in which the first fan operates in its cooling or forward direction as theforward fan and the second fan operates in its cleaning or reverse direction as the Attorney Docket No. P20047-US reverse fan;
[14] [0014] FIG. 4 is a simplified top view showing advancement of air during an interimmode in which each of the first and second fans operates in its cleaning or reversedirection as a reverse fan;
[15] [0015] FIG. 5 is a simplified schematic view of a fan control system;
[16] [0016] FIG. 6 is a first control routine that cycles the fans between the first andsecond cleaning modes during an exchanger-cleaning event;
[17] [0017] FIG. 7 is an alternative embodiment of the first control routine adding aninterim step in which both fans are reversed simultaneously between the first andsecond cleaning modes to promote debris removal;
[18] [0018] FIG. 8 is a second control routine in which successive exchanger-cleaningevents alternate between the first and second cleaning modes, with an exchanger-cooling event in a cooling mode therebetween; and
[19] [0019] FIG. 9 is a chart showing sequential reversal ofthe fans in an exchanger- cleaning event.
[20] [0020] Referring to FIG. 1, there is shown a machine 10 which may take the formof, for example, an articulated dump truck or other work vehicle having a fore-aft axis11. Exemplarily, as an articulated dump truck, the machine 10 has a front section 12and a rear section, the front and rear sections being articulated to one another andpositioned along the fore-aft axis 11. The front section 12 has the operator's stationand an engine compartment 18 in front of the operator's station. The rear sectionhas a tippable dump body configured to carry a payload.
[21] [0021] The machine 10 has a cooling system 22 for cooling a number of fluids ofthe machine 10. The cooling system 22 has a first cooling package 24, a secondcooling package 26, and a fan control system 28.
[22] [0022] The first cooling package 24 has a first fan 30 and at least one heatexchanger 32 to cool at least one ﬂuid associated with the machine 10. The first fan30 is configured to rotate in a cooling or forward direction 34-1 and an oppositecleaning or reverse direction 34-2.
[23] [0023] The second cooling package 26 has a second fan 36 and at least one heatexchanger 38 to cool at least one ﬂuid associated with the machine 10. The second Attorney Docket No. P20047-US fan 36 is configured to rotate in a cooling or forward direction 40-1 and an oppositecleaning or reverse direction 40-2.
[24] [0024] The fan control system 28 is configured to operate the first and second fans30, 36 in a cooling mode to cool one or more f|uids of the machine 10 during anexchanger-cooling event and in one or more cleaning modes to clean the at leastone heat exchanger 32, 38 of each of the first and second cooling packages 24, 26during an exchanger-cleaning event. Referring to FIG. 1, in the cooling mode, thefirst and second fans 30, 36 concurrently rotate respectively in their coolingdirections 34-1, 40-1 advancing air from a common air inlet respectively past the firstand second cooling packages 24, 26 to the first and second fans 30, 36 and outrespective air outlets.
[25] [0025] The fan control system 28 is configured to alternate successively the ﬁrstand second fans 30, 36 between a first cleaning mode and a second cleaning modeduring an exchanger-cleaning event. Referring to FIG. 2, in the first cleaning modethe first and second fans 30, 36 concurrently rotate respectively in their cleaning andcooling directions 34-2, 40-1 advancing air in a first flow direction 42 from the first fan30 to the second fan 36 past the at least one heat exchanger 32, 38 of each of thefirst and second cooling packages 24, 26. Referring to FIG. 3, in the secondcleaning mode the first and second fans 30, 36 concurrently rotate respectively intheir cooling and cleaning directions 34-1, 40-2 advancing air in a second flowdirection 44 opposite the first flow direction 42 from the second fan 36 to the first fan30 past the at least one heat exchanger 32, 38 of each of the first and secondcooling packages 24, 26.
[26] [0026] The fan control system 28 is configured to cycle the first and second fans30, 36 between the first and second cleaning modes for one or more cycles duringthe exchanger-cleaning event. For example, the fan control system 28 is configuredto cycle the fans 30, 36 between the first and second cleaning modes for one cycleduring the exchanger-cleaning event.
[27] [0027] Exemplarily, the first and second cooling packages 24, 26 are positioned onlaterally opposite sides of a fore-aft axis 11 of the machine 10 such that the first andsecond flow directions 42, 44 are laterally opposite to one another. The first coolingpackage 24 may be positioned on the right-hand side of the axis 11, and the secondcooling package 26 may be positioned on the left-hand side of the axis 11. The at Attorney Docket No. P20047-US least one heat exchanger 32 of the first cooling package 24 and the at least one heatexchanger 38 of the second cooling package 26 are positioned laterally between thefirst and second fans 30, 36. Exemplarily, an internal combustion engine 48 (e.g.,diesel engine) is positioned laterally between the first and second cooling packages24, 26.
[28] [0028] Each of the ﬁrst and second cooling packages 24, 26 may have a number ofheat exchangers. Exemplarily, the first cooling package 24 has three units of one ormore heat exchangers 32 stacked laterally relative to one another, with a laterallyoutward unit, a laterally inward unit, and a laterally intermediate unit positionedlaterally between the laterally outward and inward units. The laterally outward unit ispositioned laterally between the first fan 30 and the laterally intermediate unit. Thelaterally inward unit is positioned laterally between the laterally intermediate unit andthe engine 48. The laterally outward unit is a radiator 32-1 configured to cool enginecoolant. The laterally intermediate unit is a combination cooler having, from rear tofront, a transmission-and-retarder oil cooler 32-2 configured to cool oil of thetransmission and retarder and a hydraulic oil cooler 32-3 configured to cool hydraulicoil. The transmission-and-retarder oil cooler and the hydraulic oil cooler are adjacentto one another and are fastened to another (e.g., using bolts and nuts). The laterallyinward unit is a fuel cooler 32-4 configured to cool fuel. The first cooling package 24may be configured in any suitable fashion (e.g., the number, size, use, layout, etc. ofheat exchangers may be different for a given machine).
[29] [0029] Exemplarily, the second cooling package 26 has two units of one or moreheat exchangers 38 stacked laterally relative to one another, with a laterally outwardunit, a laterally inward unit, and a laterally intermediate unit positioned laterallybetween the laterally outward and inward units. The laterally outward unit ispositioned laterally between the second fan 36 and the laterally intermediate unit.The laterally inward unit is positioned laterally between the laterally outward unit andthe engine 48. The laterally outward unit is a radiator 38-1 configured to cool enginecoolant. The laterally intermediate unit is a combination cooler having, from rear tofront, 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 configuredto cool an axle and associated brakes (e.g., the front axle of an articulated dumptruck), and a charge-air cooler 38-4 configured to cool pressurized engine intake air.
[30] [0030] Exemplarily, the two radiators 32-1, 38-1 of the first and second coolingpackages 24, 26 are ﬂow-parallel to one another. ln such a case, a first node iscoupled ﬂuidly to a coolant outlet of the engine 48 and respective coolant inlets ofthe two radiators, and a second node is coupled ﬂuidly to respective coolant outletsof the two radiators and a coolant inlet of the engine 48.
[31] [0031] Referring to FIG. 5, the fan control system 28 may be configured in anysuitable manner to control operation of the fans 30, 36. Exemplarily, the fan controlsystem 28 has a first electro-hydraulic system 68 for the first fan 30 and a secondelectro-hydraulic system 69 for the second fan 36, the systems 68, 69 sharing ahydraulic ﬂuid reservoir tank. Each electro-hydraulic system 68, 69 has a variabledisplacement hydraulic pump 70 and a hydraulic motor 72. The motor 72 is coupledmechanically to the respective fan 30, 36 to drive that fan in either direction. Thepump 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 system68 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 iselectronically controlled using a displacement control mechanism discussed below.The controller 58 is coupled electrically to a speed sensor (e.g., Hall-effect sensorwith 12 pulses per revolution) in each motor 72 to receive information indicative ofthe 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, areverse valve 76, and a speed valve 78. The directional control valve 74 isconfigured to direct hydraulic ﬂuid selectively to either of two work ports of the motor72 to control the direction of rotation of the motor 72. The reverse valve 76 isconfigured as an on/off valve and is coupled electrically to an electric first controller58 of the machine 10 (e.g., chassis control unit) so as to be under the control of thecontroller 58. The reverse valve 76 is coupled hydraulically to the pump 70 and a Attorney Docket No. P20047-US pilot port of the directional control valve 74 to direct supply pressure to the pilot portof the directional control valve 74 when the solenoid of the reverse valve 76 isenergized by the controller 58. Energizing and de-energizing the reverse valve 74causes the spool of the directional control valve 74 to shift accordingly to change thedirection of flow to the motor 72 and thus the direction of rotation of the respectivefan 30, 36.
[33] [0033] An intermediate, transition section of the directional control valve 74 isconfigured to couple ﬂuidly the two work ports of the motor 72 through the valve 74momentarily allowing the respective fan 30, 36 to freewheel during shifting of thespool between a first position directing hydraulic fluid to a first work port of the motor72 and a second position directing hydraulic ﬂuid to a second work port of the motor72. Such a work port connection promotes motor life by avoiding a suddendeadhead of the motor 72 that might otherwise occur in the absence of the transitionsecüon.
[34] [0034] Each electro-hydraulic system 68, 69 has a first pressure-relief valve 77 anda second pressure-relief valve 79. The first pressure-relief valve 77 is coupled fluidlyto 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 firstpressure-relief valve 77 in parallel thereto, and has a pressure-relief setting lowerthan that of the valve 77. The second pressure-relief valve 77 is coupled electricallyto the first controller 58 so as to be under the control of that controller 58. When thecontroller 58 energizes the solenoid of the reverse valve 76, it energizes the solenoidof the second pressure-relief valve 79 momentarily so as to relieve pressure in thepressure supply line as the spool of the directional control valve 74 passes throughits intermediate, transition section, avoiding transmission of a pressure spike toupstream components with respect to the first electro-hydraulic system 68 and to thepump 70 with respect to the second electro-hydraulic system 69.
[35] [0035] The speed valve 78 of the first electro-hydraulic system 68 is configured, forexample, as a proportional load-sense relief valve and is operable to vary the speedof rotation ofthe fan 30. The speed valve 78 is coupled electrically to the controller58 so as to be under the control of the controller 58 (e.g., by pulse-width modulationor “PWM” such as, for example, PWM to ground with system voltage to high side ofvalve 78 in response to vehicle start-up). The controller 58 is configured to Attorney Docket No. P20047-US command the speed valve 78 to open by energizing its solenoid in order to bleedhydraulic 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.
[36] [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 controlmechanism for the pump 70 of the system 69. The displacement control mechanismhas a hydraulic first cylinder 86 and a hydraulic second cylinder 88, both cylinders86, 88 coupled to the displacement control of the pump 70 (e.g., swash plate). Thespeed valve 78 has two work ports coupled ﬂuidly respectively to the first cylinder 86and the second cylinder 88. The speed valve 78 is spring-biased to route hydraulicfluid from the supply line to the first cylinder 86 so as to displace the pump 70 fullyfor maximum speed of the second fan 36. The speed valve 78 is coupled electricallyto 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 systemvoltage to high side of valve 78 in response to vehicle start-up). The controller 58 isconfigured to command the speed valve 78 to shift by energizing its solenoid in orderto route hydraulic fluid from the supply line to the second cylinder 88 so as to slowthe second fan 36. De-energizing the solenoid of the speed valve 78 increases thefan speed.
[37] [0037] Each pump 70 can be a pump dedicated to the respective fan 30, 36, or itmay 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 thefirst 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 hydraulicpump of the machine 10. ln such a case, the pump 70 of the first electro-hydraulicsystem 68 may be driven off of the transmission, coupled to the engine 48, and thepump 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 stackedbehind it.
[38] [0038] For simplification, with respect to the first electro-hydraulic system 68,components between the “shared” pump 70 and the motor 72 associated with thefan 30 are shown, although the other functions are not shown. Such componentsinclude an attenuator 80, a priority valve 81, an electro-hydraulic cut-off valve 82, Attorney Docket No. P20047-US 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. Thepriority valve 81 establishes priority ﬂow for steering (and also for brakes but mainlyfor steering). The cut-off valve 82 is closed during tipping of the dump body of themachine 10 to decrease the time that it takes to tip the dump body in response to asignal from the first controller 58 due to movement of the dump body (e.g., causedby displacement of the dump lever or actuation of a dump body-up button or a dumpbody-down button). The compensator valve 84 regulates the pressure supplied tothe 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 neededfor the fan 30, the compensator valve 84 will reduce that pressure to the pressurecalled for by the speed valve 78). The load-sense system for the “shared” pump 70is identified as “LS1” in FIG. 5, and exemplarily includes a network of shuttle valvesassociated with various functions to establish the load-sense signal back to thepump control. A system pressure-relief unit 89 is positioned in the system 68 aheadof the function(s) of the system 68.
[39] [0039] Referring to FIG. 6, there is shown a flowchart of a control routine 110 forcleaning the heat exchangers 32, 38 of the first and second cooling packages 24, 26in the cleaning mode. The cleaning mode may be initiated automatically or manuallyby the operator. Automatic initiation occurs in step 112, and manual initiation occursin step 114.
[40] [0040] ln step 112, the electric first controller 58 of the control system 28 (e.g., thechassis control unit) monitors elapsed time (t) since the end of the last cleaningevent of the cooling packages 24, 26, and determines if a predetermined period oftime (At) has elapsed since the end of that event. A timer 62 tracks such elapsedtime, and is included in the controller 58, or may be a stand-alone device or part ofanother controller. The predetermined period of time may be selected by theoperator through, for example, a display monitor at the operator's station (e.g., ßhour, 1 hour, 2 hours, 3 hours, 4 hours), or it may be a default value (e.g., 4 hours).lf the predetermined period of time has elapsed, the routine 110 advances to step116. lf no, the controller 58 continues to monitor elapsed time since the lastexchanger-cleaning event.
[41] [0041] ln step 114, an operator or other person can manually request activation of Attorney Docket No. P20047-US the cleaning mode through a display monitor at the operator's station. lf a manualrequest has been received, the routine 110 advances to step 116.
[42] [0042] ln step 116, the controller 58 determines whether any of a number of inhibitconditions is present. The conditions monitored may include, for example: thetemperature 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 cleaningevent will reduce cooling); the windshield wipers are off (since wiper activation isindicative of rain which could cause a cloud ofdust discharged from the machine 10during cleaning to stick to windows of the operator's station); and a diesel particulatefilter is being regenerated (e.g., based on a CAN message received by the controller58 from an electric second controller 60 such as an engine control unit). Thecontroller 58 receives inputs indicative of whether any such inhibit condition exists. lfthe controller 58 determines that an inhibit condition exists, the controller 58 waits toactivate the cleaning mode until such condition terminates. lfa manual request forcleaning was received, the controller 58 may initiate activation of an alert (e.g., onthe display monitor) indicating that the cleaning mode is inhibited. lf no inhibitcondition exists, the routine 110 advances to step 118.
[43] [0043] Other inhibit conditions may include, for example, one or more of thefollowing: engine speed is not greater than a threshold engine speed (e.g., 1400rpm), since lower engine speeds may not provide sufficient hydraulic flow to reachmaximum fan speed (in other words, engine speeds greater than 1400 rpm mayprovide sufficient hydraulic flow to reach maximum fan speed; it is thought thatengine idle speed may even be sufficient); and ground speed ofthe machine 10 isgreater than a threshold ground speed (e.g., 5 miles per hour), so as to reduce thelikelihood that a person is in the path ofdischarge.
[44] [0044] ln step 118, the controller 58 activates an exchanger-cleaning event inwhich the controller 58 alternates successively the first and second fans 30, 36between the first cleaning mode and the second cleaning mode. Such alternatingsuccession 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 cleaningmode.
[45] [0045] ln step 118-1 of step 118, the controller 58 activates the first cleaning mode.ln the first cleaning mode, the first and second fans 30, 36 concurrently rotate Attorney Docket No. P20047-US respectively in their cleaning and cooling directions 34-2, 40-1 advancing air in a firstflow direction 42 laterally relative to the fore-aft axis 11 from the first fan 30 to thesecond fan 36 past the at least one heat exchanger 32, 38 of each of the first andsecond cooling packages 24, 26.
[46] [0046] Referring to FIG. 9, to reverse the first fan 30 from its cooling direction to itscleaning direction, in time T1, the controller 58 commands operation of the speedvalve 78 associated with the first fan 30 (gradually energizes its solenoid) (i.e., thefirst speed valve 78) to ramp down the speed of the first fan 30 at a predeterminedrate (e.g., 100 rpm/second) toward a zero fan speed using the speed informationfrom the speed sensor in the first fan motor 72. Such ramping down helps to avoidfan motor cavitation. When the fan speed reaches a predetermined fan idle speed(e.g., 600 rpm), the controller 58 commands operation ofthe first speed valve 78 soas to command the first fan 30 to the zero fan speed (i.e., commands maximumcurrent to the valve 78 assuming no fault requiring abort), and begins to monitor thefan speed for up to a predetermined period oftime (e.g., 10 seconds) using thespeed information from the speed sensor in the first fan motor 72 (the controller 58 isunable to control the 100 rpm/second rate below the fan idle speed). The solenoid ofthe reverse valve 76 associated with the first fan 30 9 (i.e., the first reverse valve 76)is de-energized during time T1.
[47] [0047] lf, during the predetermined period of time, the fan speed reaches zero, timeT2 starts immediately. lf, at the end of the predetermined period of time, the fanspeed 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. lf neither conditionoccurs, the controller 58 aborts reversal of the first fan 30, and begins reversal of thesecond 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 (graduallydecreases its current) to ramp up the speed of the first fan 30 at a predeterminedrate (e.g., 100 rpm/second) to a variable forward speed based on the cooling need ofthe first cooling package 24 using the speed information from the speed sensor inthe first fan motor 72.
[48] [0048] ln time T2, the controller 58 commands operation of the first speed valve 78so 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 11 Attorney Docket No. P20047-US speed of the first fan 30 for a predetermined period of time using the speedinformation from the speed sensor in the first fan motor 72 to confirm if the fan speedremains below the low-speed threshold. The predetermined period of time may bebetween a few milliseconds and a few seconds. lt may be, for example, 10milliseconds or, preferably, two seconds to ensure that the fan speed has indeedreduced to a desired level for changing its direction of rotation since the speedsensor does not indicate direction of rotation. lf, during the predetermined period oftime, the fan speed of the first fan 30 is equal to or greater than the low-speedthreshold, the controller 58 aborts reversal of the first fan 30 and begins reversal ofthe second fan 36 (i.e., advances the second fan 36 from T1-T7), and, regarding thefirst 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 apredetermined rate (e.g., 100 rpm/second) to a variable forward speed based on thecooling need of the first cooling package 24 using the speed information from thespeed sensor in the first fan motor 72. The solenoid of the first reverse valve 76 isde-energized during time T2.
[49] [0049] ln time T3, the controller 58 energizes the solenoid of the first reverse valve76 and commands operation of the first speed valve 78 (proportionally energizes itssolenoid) so as to reverse the direction of hydraulic ﬂow to the first fan motor 72 andcommand 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 speedsensor in the first fan motor 72 for up to a predetermined amount of time (e.g., twoseconds) to confirm if a non-zero fan speed has been achieved, as there will be anatural initial system delay (due, for example, to solenoid saturation, valvehysteresis, and time to measure fan speed). lf the non-zero fan speed has not beenachieved within the predetermined period of time, the controller 58 aborts reversal ofthe first fan 30 and begins reversal of the second fan 36 (i.e., advances the secondfan 36 from T1-T7). During abort of the first fan 30, the controller 58 de-energizesthe solenoid of the first reverse valve 76 and commands operation of the first speedvalve 78 (gradually decreases its current) to ramp up the speed of the first fan 30 ata predetermined rate (e.g., 100 rpm/second) to a variable forward speed based onthe cooling need of the first cooling package 24 using the speed information from thespeed sensor in the first fan motor 72. 12 Attorney Docket No. P20047-US
[50] [0050] Time T4 begins when the controller 58 determines that the first fan 30 hasachieved a non-zero fan speed using the speed information from the speed sensor inthe first fan motor 72. ln time T4, the controller 58 continues to energize thesolenoid of the first reverse valve 76 and to energize proportionaiiy the solenoid ofthe first speed valve 78 so as to command the predetermined reverse speedthreshold, 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 beenachieved. lf the predetermined reverse speed threshold has not been achieved inthe 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).
[51] [0051] To abort reversal of the first fan 30 in time T4, the controller 58 commandsoperation of the first speed valve 78 so as to command the first fan 30 to a zero fanspeed (i.e., commands maximum current to the valve 78 assuming no fault requiringmachine shutdown and restart so as to de-energize the valve 78 thereby resetting itin case the second speed valve 78 is malfunctioning) and monitors the fan speed forup to a predetermined period of time (e.g., 10 seconds) using the speed informationfrom the speed sensor in the first fan motor 72. lf, during the predetermined periodof time, the fan speed reaches zero, or, at the end of the predetermined period oftime, the fan speed is at least below the low-speed threshold, the controller 58continues 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-energizesthe solenoid of the first reverse valve 76 and commands operation of the first speedvalve 78 (gradually decreases its current) to ramp up the speed of the first fan 30 ata predetermined rate (e.g., 100 rpm/second) to a variable forward speed based onthe cooling need of the first cooling package 24 using the speed information from thespeed sensor in the first fan motor 72. The controller 58 begins reversal of thesecond fan 36 when the speed of the first fan 30 drops below the low-speedthreshold (i.e., advances the second fan 36 from T1-T7).
[52] [0052] When the predetermined reverse speed threshold is reached, time T5begins, in which the controller 58 continues to energize the solenoid of the firstreverse valve 76 and to energize the solenoid of the first speed valve 78 so as tocommand the speed of the first fan 30 to be the reverse speed threshold for a 13 Attorney Docket No. P20047-US predetermined period of reverse time. That predetermined period of time may be, forexample, 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 theoperator's station. Once the fan speed reaches the reverse speed threshold, thecontroller 58 starts counting the amount of reverse time in which the first fan 30 is ator above the reverse speed threshold. lf the fan speed drops below the threshold,the controller 58 stops counting the reverse time. lnstead, the controller 58 startscounting the amount of time below the threshold. As such, when the fan speed is ator above the threshold, time is accrued toward the predetermined period of reversetime, whereas, when the fan speed is below the threshold, time is accrued toward apredetermined period of fault time which may be, for example, 30 seconds. Thereverse time and the fault time are thus both cumulative. lf the reverse time isreached before the fault time is reached, the controller 58 proceeds to time T6. lf thefault time is reached before the reverse time is reached, the controller 58 abortsreversal of the first fan 30, and begins reversal of the second fan 36. The abortsequence in time T5 is the same as the abort sequence in T4.
[53] [0053] ln time T6, the controller 58 commands operation of the first speed valve 78to command the speed of the first fan 30 to zero (i.e., commands maximum currentto the valve 78 assuming no fault requiring abort), at an uncontrolled rate. Since thisspeed decrease is uncontrolled (the first fan 30 freewheels), the controller 58monitors 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. lf,during the predetermined period of time, the fan speed reaches zero, time T7 startsimmediately. lf, at the end of the predetermined period of time, the fan speed doesnot reach zero but reaches below the low-speed threshold (e.g., 100 rpm), time T7starts at the end of the predetermined period of time. lf neither condition occurs, thecontroller 58 aborts the exchanger-cleaning event altogether in order to avoidreversing both fans 30, 36 at the same time, and may therefore require the machine10 to be shut down and re-started (e.g., so as to de-energize the second speedvalve 78 thereby resetting it in case the second speed valve 78 is malfunctioning).[0054] ln time T7, the controller 58 commands operation of the first speed valve 78so 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 14 Attorney Docket No. P20047-US speed of the first fan 30 for a predetermined period of time using the speedinformation from the speed sensor in the first fan motor 72 to confirm if the fan speedremains below the low-speed threshold. The predetermined amount of time may bebetween a few milliseconds and a few seconds. lt may be, for example, 10milliseconds or, preferably, two seconds to ensure that the fan speed has indeedreduced to a desired level for changing its direction of rotation since the speedsensor does not indicate direction of rotation. lf the fan speed remains below thelow-speed threshold for the predetermined period of time, at the end of T7, thecontroller 58 de-energizes the solenoid of the first reverse valve 76 and commandsoperation of the first speed valve 78 (gradually decreases its current) to ramp up thespeed of the first fan 30 at a predetermined rate (e.g., 100 rpm/second) to a variableforward speed based on the cooling need of the first cooling package 24 using thespeed information from the speed sensor in the first fan motor 72. lf the fan speeddoes not remain below the low-speed threshold, the controller 58 aborts theexchanger-cleaning event altogether in order to avoid reversing both fans 30, 36 atthe 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 incase the second speed valve 78 is malfunctioning).
[55] [0055] The routine 110 advances to step 118-2 of step 118 as soon as the zero fanspeed of the first fan 30 has been achieved in T6 or if the fan speed of the first fan30 is below the low-speed threshold at the end of the predetermined period of time ofT6. ln step 118-2, the controller 58 activates the second cleaning mode, whileconcluding the first cleaning mode by advancing the first fan 30 through T7 andramping its fan speed to a forward speed.
[56] [0056] ln the second cleaning mode, the first and second fans 30, 36 concurrentlyrotate respectively in their cooling and cleaning directions 34-1, 40-2 advancing air ina second flow direction 44 opposite the first flow direction 42 laterally relative to thefore-aft axis 11 from the second fan 36 to the first fan 30 past the at least one heatexchanger 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 andaborts in the same manner if necessary, except that, in the event of an abort ofreversal of the second fan 36 in any of T1-T5, the controller 58 aborts the Attorney Docket No. P20047-US exchanger-cleaning event altogether (i.e., does not reverse the first fan 30 since thefirst fan 30 would have already been reversed). With respect to the second cleaningmode, the speed valve 78 associated with the second fan 36 (second speed valve78) and the reverse valve 76 associated with the second fan 36 (second reversevalve 76) are involved. ln the event of an abort during T6 or T7, the controller 58aborts the exchanger-cleaning event altogether, and may therefore require themachine 10 to be shut down and re-started (e.g., so as to de-energize the secondspeed valve 78 thereby resetting it in case the second speed valve 78 ismalfunctioning).
[57] [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.ln step 120, if the fan speed remains below the low-speed threshold for thepredetermined period of time, at the end of T7, the controller 58 de-energizes thesecond 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 apredetermined rate (e.g., 100 rpm/second) to a variable forward speed based on thecooling need ofthe second cooling package 26 using the speed information from thespeed sensor in the second fan motor 72. As alluded to above, if the fan speed doesnot remain below the low-speed threshold, the controller 58 aborts the exchanger-cleaning event altogether, and may therefore require the machine 10 to be shutdown and re-started (e.g., so as to de-energize the second speed valve 78 therebyresetting it in case the second speed valve 78 is malfunctioning).
[58] [0058] During reversal of the first fan 30, the controller 58 commands operation ofthe second fan 36 at a forward speed based on the cooling need of the coolingpackage 26 through de-energization of the second reverse valve 76 and proportionalcontrol of the second speed valve 78. An electric second controller 60 (e.g., enginecontrol 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 needof 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 temperaturesensor, and sends this value to the first controller 58 for determination of whether aninhibit condition exists. The second controller 60 sends that fan speed to the electric 16 Attorney Docket No. P20047-US first controller 58 which controls the second speed valve 78 so as to operate thesecond fan 36 at that fan speed. The first fan 30 is operated in a correspondingmanner during reversa| of the second fan 36.
[59] [0059] Referring to FIGS. 4 and 7, an alternative embodiment of the step 118 isshown as step 218, and includes an interim step 218-3 due to overlap of activation ofthe first and second cleaning modes in steps 218-1 and 218-2, respectively. ln step218-3, the controller 58 commands operation of the fans 30, 36 such that the fans30, 36 concurrently rotate respectively in their cleaning directions for an interimpredetermined period of time so as to blow air inwardly toward the engine 48 tocause debris to blow out any openings in the compartment 18 (e.g., any openingsbetween panels, and front grill).
[60] [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 36continues to operate at a variable fan cooling speed. While the first fan 30 is still inT5 or immediately aftervvards during which the controller 58 keeps the first fan 30 atthe predetermined reverse speed threshold (e.g., 1600 rpm), the controller 58activates the second cleaning mode reversing the second fan 36 from its coolingdirection 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 thefan speed of the fans 30, 36 at the predetermined reverse speed threshold for aninterim predetermined period of time (e.g., 10 seconds). Upon elapse of the interimpredetermined 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 commandsthe first fan 30 to a variable forward speed (assuming no abort). lt subsequentlyconcludes the second cleaning mode, advancing the second fan 36 in sequencethrough T5, T6, and T7, after which it commands the second fan 36 to a variableforward speed (assuming no abort).
[61] [0061] Thus, the controller 58 may be configured to operate the first and secondfans 30, 36 sequentially in the first cleaning mode, the interim cleaning mode, andthe second cleaning mode during an exchanger-cleaning event, with the first andsecond cleaning modes overlapping to provide the interim cleaning mode.
[62] [0062] Referring to FIG. 8, a control routine 310 provides an alternativeembodiment to control routine 110. The control routine 310 alternates between the 17 Attorney Docket No. P20047-US cooling mode and a Cleaning mode, and the cleaning mode may be activated in anysuitable 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 notpresent (e.g., step 116). ln other words, the routine 310 will perform steps 112, 114,and 116 before performing a cleaning mode.
[63] [0063] The control routine 310 is different in that each exchanger-cleaning eventinvolves only one of the first and second cleaning modes such that successiveexchanger-cleaning events alternate between the first and second cleaning modes.For example, the control routine 310 may advance from the cooling mode in step316 to only the first cleaning mode in step 318 (does not include the second cleaningmode during this exchanger-cleaning event). The routine 310 may then advanceback to the cooling mode in step 320 and then to only the second cleaning mode instep 322 (does not include the first cleaning mode during this exchanger-cleaningevent). This pattern may continue, promoting fuel economy since both cleaningmodes are not activated during an exchanger-cleaning event.
[64] [0064] ln step 318, the controller 58 operates the first and second fans 30, 36 intheir cleaning and cooling directions, respectively, in a manner similar to what isdiscussed in connection with step 118-1 of FIG. 6. ln step 320, the controller 58returns the first fan 30 to its cooling direction to a variable forward speed based oncooling need. ln step 322, the controller 58 operates the first and second fans 30, 36in their cooling and cleaning directions, respectively, in a manner similar to what isdiscussed in connection with step 118-2 of FIG. 6. The routine 310 then advancesback to step 316, in which the controller 58 returns the second fan 36 to its coolingdirection to a variable forward speed based on cooling need. The controller 58 maythus be configured to alternate successive exchanger-cleaning events between thefirst cleaning mode and the second cleaning mode. ln the event an abort of thereversal sequence of either fan 30, 36 is triggered in any of T1 -T7, the controller 58performs the abort sequence associated with the respective time period (discussedabove in connection with routine 110 and fan 30) without reversing the other fan,thereby aborting the exchanger-cleaning event altogether.
[65] [0065] ln the control routine 110, it is thought that, during each of the first andsecond cleaning modes, about 86 percent of the debris in the engine compartment18 is removed from the engine compartment while about 10 percent remains. 18 Attorney Docket No. P20047-US
[66] [0066] ln the control routines discussed herein, during a Cleaning mode, theforward fan (i.e., the fan operating in its forward direction) is operated at a variableforward speed based on cooling needs. Alternatively, the controller 58 may operatethe forward fan at its maximum calibrated operating speed.
[67] [0067] Cooling is more efficient in the cooling mode than any of the cleaningmodes, but also takes place during the exchanger-cleaning event.
[68] [0068] The cooling system 22 may be used with an articulated machine (e.g.,machine 10) or a non-articulated machine.
[69] [0069] While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such illustration and description is to beconsidered as exemplary and not restrictive in character, it being understood thatillustrative embodiment(s) have been shown and described and that all changes andmodifications that come within the spirit of the disclosure are desired to be protected.lt will be noted that alternative embodiments of the present disclosure may notinclude all of the features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art may readily devisetheir own implementations that incorporate one or more of the features of the presentdisclosure and fall within the spirit and scope of the present invention as defined by the appended claims. 19

权利要求:
Claims (10)
[1] 1. A cooling system for a machine, comprising: a first cooling package comprising a first fan and at least one heat exchangerto cool at least one fluid associated with the machine, the first fan configured torotate in a cooling direction and an opposite cleaning direction, a second cooling package comprising a second fan and at least one heatexchanger to cool at least one ﬂuid associated with the machine, the second fanconfigured to rotate in a cooling direction and an opposite cleaning direction, and a fan control system configured to alternate the first and second fans betweena first cleaning mode and a second cleaning mode, wherein, in the first cleaningmode the first and second fans concurrently rotate respectively in their cleaning andcooling directions advancing air in a first flow direction from the first fan to thesecond fan past the at least one heat exchanger of each of the first and secondcooling packages, and, in the second cleaning mode the first and second fansconcurrently rotate respectively in their cooling and cleaning directions advancing airin a second flow direction opposite the first flow direction from the second fan to thefirst fan past the at least one heat exchanger of each of the first and second coolingpackages.
[2] 2. The cooling system of claim 1, wherein the fan control system isconfigured to alternate successively the first and second fans between the firstcleaning mode and the second cleaning mode during an exchanger-cleaning event.
[3] 3. The cooling system of claim 1, wherein in the first cleaning mode thefan control system is configured to command operation of the first fan at at least apredetermined reverse speed threshold for a predetermined period of time, and inthe second cleaning mode the fan control system is configured to commandoperation of the second fan at at least the predetermined reverse speed threshold forthe predetermined period of time.
[4] 4. The cooling system of claim 3, wherein in each of the first and secondcleaning modes the predetermined period of time is cumulative excluding time thatthe respective first or second fan spends below the predetermined reverse speedthreshold.
[5] 5. The cooling system of claim 3, wherein the fan control system is Attorney Docket No. P20047-US configured to abort reversal of the first fan upon occurrence of an abort event, and isconfigured to begin reversal of the second fan when a speed of the first fan reachesa zero fan speed or at the end of a predetermined period of abort time if the speed ofthe first fan is below a low-speed threshold.
[6] 6. The cooling system of claim 1, wherein the fan control system isconfigured to alternate successive exchanger-cleaning events between the firstcleaning mode and the second cleaning mode.
[7] 7. The cooling system of claim 1, wherein the fan control system isconfigured to operate the first and second fans sequentially in the first cleaningmode, an interim cleaning mode, and the second cleaning mode during anexchanger-cleaning event, and, in the interim cleaning mode, the first and secondfans concurrently rotate respectively in their cleaning directions.
[8] 8. A machine comprising the cooling system of claim 1, wherein the firstand second cooling packages are positioned on laterally opposite sides of a fore-aftaxis of the machine such that the first and second ﬂow directions are laterallyopposite to one another.
[9] 9. The machine of claim 8, wherein the at least one heat exchanger of thefirst cooling package and the at least one heat exchanger of the second coolingpackage are positioned laterally between the first and second fans.
[10] 10. The machine of claim 9, wherein the machine is a work vehicle. 21

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法律状态:
2016-10-11| NAV| Patent application has lapsed|

优先权:

申请号 | 申请日 | 专利标题

US13/328,142|US20130153180A1|2011-12-16|2011-12-16|Cooling System With Dual Reversing Fans|

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