SERV1852_02_TXT8
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SERV1852-02 October 2008
GLOBAL SERVICE LEARNING TECHNICAL PRESENTATION
320D-336D HYDRAULIC EXCAVATORS TIER III ENGINES DEMAND FAN SYSTEMS
Service Training Meeting Guide (STMG)
320D-336D HYDRAULIC EXCAVATORS TIER III ENGINES DEMAND FAN SYSTEMS AUDIENCE Level II - Service personnel who understand the principles of machine systems operation, diagnostic equipment, and procedures for testing and adjusting.
CONTENT This presentation provides an introduction and describes the components and systems operation of the 320D-336D hydraulic excavator demand fan systems. Additional presentations will cover the machine walkaround, engines, pilot system, main control valve group, implements, swing system, travel system, and tool control systems in more detail. This presentation may be used for self-paced and self-directed training.
OBJECTIVES After learning the information in this presentation, the technician will be able to: 1. identify the correct operation of the demand fan systems used on the 300D Series hydraulic excavators for engine cooling, and 2. diagnose problems in the fan systems.
REFERENCES 320D Hydraulic Excavator Specalog 323D L and 323D LN Hydraulic Excavators 324D Hydraulic Excavator Specalog 325D Hydraulic Excavator Specalog 328D Hydraulic Excavator Specalog 330D Hydraulic Excavator Specalog Machine Monitoring System - Systems Operation Self-study "300D Series Hydraulic Excavators, 345C Hydraulic Excavator, and 365C & 385C Large Hydraulic Excavators iTIM " '300C' Series Hydraulic Excavators-Electronic Control Systems" iTIM "325C Hydraulic Excavators-Hydraulic Systems" 325D Hydraulic Schematic
Estimated Time: 1 Hour Illustrations: 41 Form: SERV1852-02 Date: September 2008 © 2008 Caterpillar
AEHQ5856 HEHH3327 AEHQ5663 AEHQ5665 AEHQ5706 AEHQ5667 RENR8068 SERV7032 SERV2693 SERV2701 KENR6157
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Text Reference Demand Fan Systems
TABLE OF CONTENTS INTRODUCTION ........................................................................................................................5 HYDRAULIC DEMAND FAN SYSTEM...................................................................................6 Cat ET Screens for the Hydraulic Cooling Demand Fan .....................................................19 Monitor Screens for the Hydraulic Cooling Demand Fan ...................................................20 VISCONIC DEMAND FAN SYSTEM (ATTACHMENT).......................................................33 Cat ET Screens for the Visconic Cooling Demand Fan .......................................................46 Monitor Screens for the Visconic Cooling Demand Fan .....................................................51 CONCLUSION...........................................................................................................................52
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PREREQUISITES "Fundamentals of Mobile Hydraulics Self Study Course" "Fundamentals of Power Train Self Study Course" "Fundamentals of Electrical Systems Self Study Course" "Fundamentals of Engines Self Study Course"
TEMV3002 TEMV3003 TEMV3004 TEMV3001
NOTES Nomenclature Change: During the fourth quarter of 2008, the 325D and 330D nomenclature changed. The 325D became the 329D and the 330D became the 336D for most arrangements. The exceptions are as follows: - The nomenclature for the 325D MH and 330D MH did not change. - The nomenclature for the 325D FM and 330D FM did not change. - The 325D HD HW did not change into 329D HD HW. This model is being discontinued. However, the 330D HD HW changed to the 336D HD HW.
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Text Reference Demand Fan Systems
320D - 336D EXCAVATORS - TIER III ENGINES
DEMAND FAN SYSTEMS
© 2008 Caterpillar
1
INTRODUCTION There are two types of demand systems used on the 320D-336D Hydraulic Excavator to control the cooling fan for the engine: - Hydraulic demand fan system (330D/336D Only): The hydraulic demand fan system is made up of a fan motor and fan pump to cool the hydraulic oil, engine radiator, fuel cooler, and the ATAAC. A reversing fan attachment is available for the hydraulic demand fan system. - Visconic demand fan system (320D, 321D, 323D, 324D, 325D, 328D and 329D): The visconic demand fan system uses a viscous coupling between the engine mounted, belt driven fan drive hub and the fan assembly. NOTE: The cooling fan viscous coupling is sometimes called the fan clutch. A fan clutch is a thermostatically-controlled device. When the engine is cool or even at normal operating temperature, the fan clutch partially disengages the engine's mechanically-driven cooling fan. This decoupling saves power since the engine does not have to fully drive the fan. If engine temperature rises above the fan clutch's engagement temperature setting, the fan becomes fully engaged, When the fan clutch is fully engaged, the fan draws a higher volume of ambient air through the radiator, which in turn serves to maintain or lower the engine coolant temperature to an acceptable level.
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Text Reference Demand Fan Systems Coolant Temp Sensor
Fill Cap Coolant Expansion Tank Radiator
Intake Manifold Air Temperature Sensor
Thermostat Housing To Cylinder Block
Coolant Bypass Tube Water Pump
ATAAC
Top Tank
Cab Heater
Fan Motor
Hottest
> 92 C
Increasing Coolant Temperature
87 C
Coldest
< 81 C
Engine Oil Cooler Engine ECM
Monitor
Machine ECM CAN Data Link
Hydraulic Oil Cooler Slow Return Check Valve
CDL Case Drain Filter
Fan Drive Pump
OK
Main Return Filter
Hydraulic Oil Temp Sender
Hydraulic Circuits
330D/336D HYDRAULIC DEMAND FAN COOLING SYSTEM ENGINE AT OPERATING TEMPERATURE
2
HYDRAULIC DEMAND FAN SYSTEM The hydraulic demand fan system is made up of a fan motor and fan pump to cool the hydraulic oil, engine radiator, fuel cooler, and the ATAAC. The electronically controlled, variable displacement, piston fan pump is driven off of the main hydraulic system drive pump. The fan pump flow output is controlled by the angle of the swashplate. A solenoid on the fan pump receives a PWM signal from the Machine ECM to control the pump swashplate. When the machine is running, the hydraulic oil temperature sender and the engine coolant temperature sensor sends signals to the Engine ECM. The Engine ECM then sends this information to the Machine ECM. The Machine ECM picks up the hydraulic temperature through the monitor.
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The Machine ECMs interpret the information from these inputs to send a PWM signal to the fan pump solenoid to control the angle of the pump swashplate to control the pump flow. A higher temperature input will cause the Machine ECM to send a reduced PWM signal to the fan pump solenoid. The reduced signal causes the pump to upstroke to increase pump flow, which increases the speed of the fan for more cooling capacity.
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Text Reference Demand Fan Systems
8
4
1
2
5
3 6
7
3
The variable displacement fan pump is driven off of the drive pump, which is part of the main pump group (2). The pump control valve group (3) features a pressure control solenoid (4), which is controlled by the Engine ECM. The pump control valve group has two adjustment screws: - The upper screw, next to the pump control solenoid, is below the cap (5). This screw is used to adjust the pump control spool. - The lower screw (6), below the pump control valve group, is used to adjust the pressure control spool. The reservoir supply line (7) is below the fan pump housing, while the pump supply line (8) to the motor is above the housing. NOTE: In most cases, the two adjustment screws should not be used. The solenoid can be calibrated through Cat ET or the monitor to correctly set the fan pump control.
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1
2
4
The 330D/336D engine fan (1) is hydraulically driven by a fixed displacement motor (2). The variable displacement fan pump supplies oil to rotate the fan motor. Fan speed is varied to provide optimized cooling. The optimum fan speed is calculated using engine coolant temperature and hydraulic oil temperature. Case drain oil from the fan motor is combined with the case drain oil from the swing and travel motors. Return oil from the fan motor is sent to the return filters and into the hydraulic tank. An internal makeup valve in the fan motor is used to prevent cavitation when flow from the fan pump stops. The direction of the engine fan can be reversed on machines equipped with the reversible fan option. The fan motor rotation can be changed with the monitor. The reversal of the fan motor is used to clear debris and dust from the radiator and hydraulic oil cooler.
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Text Reference Demand Fan Systems
2
1
3 4
5
The radiator access compartment is located in front of the counterweight. The door is hinged on the right and has a locking latch on the left side to keep it closed. This door provides access for cleaning some of the cooling system components as servicing some of the fuel system and cooling system components. - hydraulic oil cooler (1) - Air to Air After Cooler (ATAAC) (2) - radiator (3) - engine coolant overflow bottle (4)
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Text Reference Demand Fan Systems
330D / 336D STANDARD HYDRAULIC FAN DRIVE SYSTEM MAXIMUM CONTROLLED FAN SPEED
Monitor CAN Data Link
Fan Pump Group
Minimum PWM Signal
Pressure Control Solenoid
OK
CDL Machine ECM Hydraulic Oil Temp Sender
Pump Control Valve
Engine ECM
Coolant Temp Sensor
Intake Manifold Air Temperature Sensor
Large Actuator Piston
Fan Motor with Makeup Valve Main Return Filter
Small Actuator Piston
6
This illustration is a schematic of the fan system with the fan at maximum controlled pressure, resulting in maximum controlled fan speed. The hydraulic demand fan is standard on the 330D/336D Hydraulic Excavators. The fan is part of the hydraulic system, but it is controlled by the Machine ECM. The intake manifold air temperature sensor and the coolant temperature sensor are inputs into the Engine ECM. The Engine ECM provides information to the Machine ECM from these two sensors. The Machine ECM also receives information from hydraulic temperature sensor through the monitor. The Machine ECM evaluates these three sensor inputs for controlling the fan. A target speed for the cooling fan is assigned for each engine speed based on the output of the various temperature sensors. The target values for the maximum fan speeds are assigned by specific software designed for the 330D/336D machine models. The Machine ECM sends a PWM signal to the fan pump proportional solenoid to control the flow from the pump. The pump flow is directed to the fan motor, to rotate the motor, which causes the fan to turn to provide engine cooling.
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When engine coolant and/or hydraulic oil temperatures are high, the fan speed is increased. If the temperatures are low, the fan speed is decreased. The higher the ambient temperature, the higher the fan speed, as well. For high temperature readings the Machine ECM sends the minimum software controlled PWM signal to the fan pump pressure control solenoid to upstroke the hydraulic pump to increase the pump flow. When maximum pump flow is sent to the fan motor, the fan rotates at the maximum software controlled rpm. Cat ET or the monitor can be used to check or calibrate the fan speed. Refer to the 330D/336D Test and Adjust Manual for the calibration procedures. Maximum mechanical pump pressure and maximum fan speed (high pressure cut-off) can be achieved by disconnecting the electrical connection to the solenoid or by using Cat ET to turn OFF the fan control (Engine ECM/Configuration screen). If communication is lost between the Engine ECM and the fan pump pressure control solenoid, the fan will default to the maximum mechanical pressure setting (high pressure cutoff). This action results in a higher system pressure. This pressure is higher than the maximum pressure controlled through the software. The fan speed is also higher than the maximum fan speed normally controlled by the software. The makeup valve in the fan motor is used to prevent cavitation when flow from the fan pump stops.
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Minimum PWM Signal Pressure Control Solenoid
Text Reference Demand Fan Systems
330D /336D FAN PUMP AND CONTROL VALVE MAXIMUM CONTROLLED FAN SPEED Pump Output to Fan Motor
Adjustment Screw
Case Drain Passage
Springs
Large Actuator
Swashplate
Pin Orifice Pressure Control Spool
Pump Control Spool
Spring
Adjustment Screw
Drive Shaft
Signal Passage to Actuator Piston
Small Actuator and Bias Spring
Piston and Barrel Assembly
7
The Machine ECM sends the minimum PWM signal (software controlled) to the fan pump pressure control solenoid when conditions require maximum controlled fan speed. The pressure control spool spring forces the top half of the pressure control spool up, against the solenoid pin and holds the lower land of the upper pressure control spool against the seat when the solenoid receives the minimum PWM signal. This movement blocks most of the pump output oil in the pump control spool spring chamber from draining to tank through the case drain passage, which causes the pump control spool spring chamber to become pressurized. The force of the spring at the top of the pump control spool, plus the pressure of the oil, is now greater than the oil pressure at the bottom of the pump control spool. The pump control spool moves down, blocking pump output oil from entering the signal passage to the large actuator piston in the pump. The large actuator piston is open to drain around the pump control spool.
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Text Reference Demand Fan Systems
The bias spring and the small actuator move the pump swashplate to an increased angle, which causes the pump to UPSTROKE. This condition provides a controlled maximum flow of oil to the fan motor and creates the maximum controlled fan pump system pressure, which results in the maximum controlled fan speed. If the solenoid fails (no current to the solenoid), the pump goes to maximum displacement. With no current to the pressure control solenoid, the pump control spool (high pressure cut-off) will limit the maximum pressure and the fan speed to its maximum rpm. This state can be achieved by disconnecting the fan pump control solenoid or by using Cat ET to turn the fan control OFF. This procedure is required when making adjustments to the fan system pressure settings. The mechanical high pressure cutoff is adjusted using the adjustment screw. When the adjustment screw is turned in (clockwise), it increases the force of the pressure control spool spring, which increases the the pump pressure required to unseat the land of the upper pump control spool, thereby increasing maximum cutoff pressure. Maximum cutoff pressure will be lowered when the screw is turned out (counter-clockwise). NOTE: The 330D/336D service manual currently does not provide test procedures for checking the maximum and minimum fan speeds outside the control of the software. The D8T and D9T Track-type Tractor uses a similar cooling fan system. The D8T and D9T test procedures for checking the maximum and minimum fan speeds can be used as reference, however, the specifications will be different. A tee for a pressure tap will also have to be installed in the line to the fan motor. The pump control spool is also shown as being adjustable. Increasing the spring setting would create higher system pressures and higher fan speeds for a given PWM signal to the pressure control solenoid and vice versa for decreasing the spring setting. If the spool is adjusted a pressure control solenoid calibration should be done to compensate for the change to the pump control spring.
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Text Reference Demand Fan Systems
330D / 336D STANDARD HYDRAULIC FAN DRIVE SYSTEM
Monitor
MINIMUM CONTROLLED FAN SPEED
CAN Data Link Fan Pump Group
Maximum PWM Signal OK
Pressure Control Solenoid
CDL Machine ECM Hydraulic Oil Temp Sender
Pump Control Valve
Engine ECM
Coolant Temp Sensor Intake Manifold Air Temperature Sensor
Large Actuator Piston
Fan Motor with Makeup Valve Main Return Filter
Small Actuator Piston
8
This illustration is a schematic of the hydraulic fan system with the fan at minimum speed. When the Machine ECM sends the maximum software controlled PWM signal to the fan pump pressure control solenoid, the pump destrokes to the minimum swashplate angle. At the minimum swashplate angle the pump produces the minimum controlled flow resulting in the fan turning at the minimum fan speed. When the fan pump pressure control solenoid is at the maximum software controlled PWM signal, the pressure control spool is unseated by the solenoid, allowing some of pump supply oil to drain to the tank. This action reduces the pressure in the spring chamber of the pump control spool and the pump control spool shifts up due to the higher pump supply pressure. When the pump control spool moves up, pump flow is directed to the large actuator. As pressure builds in the large actuator, the large actuator overcomes the bias spring and the small actuator piston to the destroke pump. With the pump destroked, oil flow to the fan motor is reduced which reduces the fan speed.
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Maximum PWM Signal
Text Reference Demand Fan Systems
330D / 336D FAN PUMP AND CONTROL VALVE
Pressure Control Solenoid
MINIMUM FAN SPEED Pump Output to Fan Motor
Adjustment Screw
Case Drain Passage
Springs
Large Actuator
Swashplate
Pin
Pressure Control Spool
Orifice
Pump Control Spool
Spring
Drive Shaft
Small Actuator and Bias Spring Adjustment Screw
Signal Passage to Actuator Piston
Piston and Barrel Assembly
9 This illustration shows the fan control valve with the fan pump at minimum displacement. If the input temperatures are below a certain value, the Machine ECM sends an increased PWM signal to the pressure control solenoid to reduce the pump flow. The solenoid plunger and pin push the pressure control spool down. With the pressure control spool pushed down, the spring chamber above the pump control spool is open to case drain around the seat on the lower end of the upper pressure control spool. There is a pressure drop across the orifice above the pump control spool. The system pressure is now greater than the pump control spool spring and the pressure above the pump control spool. The supply pressure pushes the pump control spool up to block oil in the signal passage to the actuator piston from going to drain. The pump control spool now allows pump supply oil to flow to the large actuator piston. The flow causes an increase in pressure in the large actuator piston. The large actuator overcomes the combined forces of the bias spring and small actuator to move the swashplate toward minimum angle. Pump flow decreases and therefore fan speed decreases.
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Text Reference Demand Fan Systems
With cold oil or at cold start-ups, the Machine ECM PWM signal to the pressure control solenoid is at the maximum. The pump control spool moves up and supply pressure is sent to the large actuator piston to move the swashplatetoward minimum angle. The large actuator stops moving when the vent hole through the large actuator piston is open to case drain. The pump flow is decreased to minimum to reduce the fan speed to minimum.
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Text Reference Demand Fan Systems
330D /336D REVERSING HYDRAULIC FAN DRIVE SYSTEM
Monitor CAN Data Link
Fan Pump Group
Pressure Control Solenoid
OK
CDL
Machine ECM
Hydraulic Oil Temp Sender
Pump Control Valve
Engine ECM
Pilot Oil
Reversing Solenoid Valve
Coolant Temp Sensor
Large Actuator Piston
Intake Manifold Air Temperature Sensor
Radiator
Fan Motor
Small Actuator Piston
Reversing Spool Relief Valve
Makeup Valve
Main Return Filter
10
On machines equipped with the reversing fan attachment, the Machine ECM also controls the reversing fan solenoid valve. A bi-directional fan motor will replace the standard fan motor with the reversing fan feature. Operation of the fan pump and motor makeup valve is as previously discussed. The Machine ECM will automatically activate the fan reversing solenoid valve at predetermined intervals, if the machine is equipped with the optional reversing fan. Fan reversing duration may be re-configured using Cat ET or through the monitor. When the reversing solenoid valve is energized, pilot oil is directed to the reversing spool. The reversing spool shifts causing the flow of oil to the fan motor to be reversed. The fan motor rotates in the opposite direction. The relief valve opens momentarily whenever there are any pressure spikes in the system. The relief valve also opens when the fan is first commanded to change directions (either reverse or forward). The momentum of the fan prevents the fan motor from immediate directional change when the flow of oil is reversed. The relief valve helps dissipate excess pressure that may damage the system during a directional change.
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Text Reference Demand Fan Systems
11
Cat ET Screens for the Hydraulic Cooling Demand Fan Using Cat ET, the status of the fan control system can be monitored. The system status information can be helpful when troubleshooting the cooling system.
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Text Reference Demand Fan Systems
12
After connecting Cat ET, go to the configuration screens. Under Machine Control, open up the Machine Attachments parameters to view the four cooling fan parameters. The Engine Cooling Map parameter can be changed on all machines, but is not recommended. This parameter requires special factory passwords to change the parameter. If the machine is equipped with a reversing fan then the Engine Reversing Feature Installation Status and the Engine Reverse Operation Time can also be changed. The Engine Reversing Feature Installation Status is used to change from "Installed" to "Disabled or Not Installed." The Engine Reverse Operation Time allows for changing the length of time the fan reverses during a reversing cycle.
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Text Reference Demand Fan Systems
13
Through Cat ET, one of four different cooling fan maps can be selected. The cooling maps are controlled by software. The fan maps were created to allow the factories the capability to select the fan map best suited for the marketing region each machine was being shipped to. From the factory the 330D/336D models for NACD are only and should ONLY be configured to High Ambient. 330D/336D machines for EAME are configured to High Ambient Temperature + Low Noise and ISJ machines are configured to Standard + Low Noise. The Standard cooling map is currently not being used by any of the factories. Factory passwords are required to change the cooling fan map for the 330D/336D. NOTE: The technician should never be required to change the cooling map. This parameter is for factory use only. At the first release of the 330D the software did allow the technician to change the cooling map without a factory password, but new software was sent out to prevent this from happening.
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Text Reference Demand Fan Systems
14
The configuration screen allows the technician to change from "Installed" to "Not Installed" for reversing feature for the cooling fan. If a reversing fan attachment is not installed on the machine, changing this parameter will have no affect on the fan operation. On machines equipped with a reversing fan attachment, this parameter allows the technician to turn off the reversing feature if required.
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Text Reference Demand Fan Systems
15
On the Override Parameter screen there are three cooling fan parameters that can be overridden. Parameter overrides can be used to perform various system tests that may or not be found in the Service Manual. One suggested use for the Engine Coolant Fan Sol Current Override is to enter a value of 0% to determine the maximum mechanical system pressure and 100% to determine the minimum pressure. These two values are not part of one any of the fan cooling maps. NOTE: The 330D/336D service manual currently does not provide test procedures for checking the maximum and minimum fan speeds outside the control of the software. The D8T Track-type Tractor uses a similar cooling fan system. The D8T test procedures for checking the maximum and minimum fan speeds can be used as reference, however, the specifications will be different. A tee for a pressure tap will also have to be installed in the line to the fan motor.
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Text Reference Demand Fan Systems
16
To begin the cooling fan solenoid calibration, open up the Calibration menu under Service and Select and select "Engine Cooling Fan Calibrations. The fan speed calibration consist of four stages: - standby - minimum fan speed calibration - maximum fan speed calibration - finish or "succeeded"
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Text Reference Demand Fan Systems
17
The above screen shows the standby state. Follow the directions on each screen as it appears. After the conditions are met, select "Next."
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Text Reference Demand Fan Systems
18
This screen shows the minimum fan speed calibration being performed. To adjust the current to the solenoid, click on the arrows below the Proportional Reducing Valve Adjustment Command bar. - Select the right button to increase the current to the fan pressure reducing valve (PRV) solenoid to reduce the fan speed. - Select the left button to decrease the current to the pressure reducing valve (PRV) solenoid to increase the fan speed.
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Text Reference Demand Fan Systems
19
This screen shows the maximum fan speed calibration being performed. To adjust the current to the solenoid, click on the arrows below the Proportional Reducing Valve Adjustment Command bar. As the current changes, the engine rpm will change as previously discussed.
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Text Reference Demand Fan Systems
20
If the calibration was successful, "Success" will appear in the pop-up window. The technician then selects "Finish" to complete the calibration of the fan solenoid valve. If the calibration was unsuccessful, "Failed" will appear in the pop-up window and the calibration should be started over.
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Text Reference Demand Fan Systems
330D / 336D MONITOR DEMAND FAN CALIBRATIONS SCREENS Service Menu
12:01 SERVICE
1
Calibration Menu
CALIBRATIONS
PRESS OK TO PERFORM OVERRIDE
Fan Calibration Minimum Speed
10
4
FAN SPEED
10
30
L :SET/CANCEL
-30
3
30
OK
L :START/RETURN
Fan Calibration Finish 12:01 FAN SPEED
10
04 :SUCCEEDED
30
PRESS OK TO SET THE TUNING VALUE OK
0 PRESS OK TO START CALIBRATION
03 :TUNE TO 1360.0 [rpm]
PRESS OK TO SET THE TUNING VALUE OK
-30
Fan Calibration Maximum Speed 12:01
10
01 :STANDBY
:MOVE CURSOR
02 : TUNE TO 800.0 [rpm] -30
FAN SPEED
PRESS OK TO PERFORM CALIBRATION
:MOVE CURSOR
FAN SPEED
12:01
FLOW LIMIT VALVE LEVER/PEDAL/ATCH ENGINE SPEED FAN SPEED ANGLE SENSOR LIMIT VALVES
ECM INFO STATUS CALIBRATIONS DEVICE TEST OVERRIDE CONFIGURATIONS
12:01
1
12:01
Fan Calibration Start
L :SET/CANCEL
:DOWN/UP
:DOWN/UP
:SCROLL SCREEN
:SCROLL SCREEN
PRESS L TO GO BACK TO UPPER LAYER SCREEN
L
:BACK
21
Monitor Screens for the Hydraulic Cooling Demand Fan Calibrations of the hydraulic demand fan can be done through the monitor. From the Service sub-menu screen select Calibrations. From the Calibrations sub-menu screen select Fan Speed. The fan speed calibration consist of four stages: - standby - minimum fan speed calibration - maximum fan speed calibration - finish or "succeeded" Before calibration, the technician needs to place a strip of reflective tape on the fan blade, and, setup the 9U-7400 Multitach II Group in order to read the fan speed. Do not use a phototach. The calibration must be done with the machine set at speed dial "10" and the AEC turned off. Then access the monitor to perform the calibration & press the buttons to increase or decrease the fan speed until it reaches the specified speed. Fan calibration is required when an ECM, fan control solenoid, fan motor, or fan pump has been replaced.
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Text Reference Demand Fan Systems
330D / 336D MONITOR DEMAND FAN OVERRIDE SCREEN Service Menu 12:01 SERVICE
Fan Overrides
10
12:01 OVERRIDE
ECM INFO STATUS CALIBRATIONS DEVICE TEST OVERRIDE CONFIGURATIONS
10
DESIRED ENG SPEED 8 0 0.0 [RPM] FAN MOTOR SPEED 3 0 0.0 [RPM] FAN MOTOR CUR PERCENT 0.0 [ % ]
PRESS OK TO PERFORM OVERRIDE
PRESS
TO CHANGE DATA
OK
: OVERRIDE OFF : MOVE CURSOR
22
Three parameter overrides are provided for the hydraulic demand fan. These overrides are used to conduct system tests. These tests may or may not be covered in the service manual.
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MONITOR REVERSING DEMAND FAN SERVICE / MAINTENANCE MENU SCREENS 12:01 SERVICE
10
Maintenance Menu 12:01 MAINTENANCE
PRESS
:MOVE CURSOR
10
OK
L
Fan will Reverse
10
STANDBY
PRESS
OK
TO START
REVERSE FAN MODE L
:BACK
Fan in Normal Mode. Does not Reverse
Fan Menu
Fan Menu
12:01 REVERSE FAN
10
ABORT
PRESS
TO START
:BACK
REVERSE FAN
Select Reverse Fan to turn reverse fan operation ON or OFF
ACTIVE
REVERSE FAN MODE
12:01
TO SET
:MOVE CURSOR
Fan Menu
PRESS
OK
REVERSE FAN
PRESS OK TO PERFORM MAINTENANCE
REVERSE FAN
10
Fan Menu
REVERSE FAN FLTR/FLUID INFO RECOMMENDED INTERVAL WORK HOUR INFO
MAINTENANCE PASSWORD CHANGE DIAGNOSTIC ECM INFO STATUS CALIBRATIONS
12:01
Text Reference Demand Fan Systems
OK
REVERSE FAN
:BACK
Return to Normal Mode
10
FAILED - NOT INSTALLED - HYD OIL TEMP HIGH - COOLANT TEMP HIGH - HYD LOCK SW ON - SOL MALFUNCTION PRESS
TO START
REVERSE FAN MODE L
12:01
OK
TO START
REVERSE FAN MODE L
:BACK
Fan in Normal Mode. Does not Reverse
23
Both types of fan systems can be equipped with a reversing fan option. The operation time of the reversing fan can be varied through the Service Menu. For the Service Menu a password is required. From the Service Menu, the Maintenance Menu can be accessed. Through the Maintenance Menu, the reversing fan can be turned ON or OFF. There is no separate switch in the cab to control the reversing fan.
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Text Reference Demand Fan Systems
MONITOR REVERSING DEMAND FAN SERVICE SCREENS Configuration Menu
10
12:01
CONFIGURATIONS WORK MODE CONFIG ATCH PARTS INST TOOL INSTALLATION CONTROL INST PRODUCT ID PARAMETER SETTING PRESS
OK
TO GET
PARAMETER SETTINGS :MOVE CURSOR
Under the Service Menu, select Configurations.
Parameter Menu
10
12:01
Fan Menu 12:01
PARAMETER SETTINGS OVER LOAD WARNING ONE TOUCH LOW IDLE GAIN/RESPONSE AUTO LUB SYSTEM UHB REVERSE FAN PRESS
OK
REVERSE FAN
OPERATION TIME 100 [sec]
PRESS
TO SET
REVERSE FAN
OK
TO SET
DATA
:MOVE CURSOR
Under the Parameter Settings Menu select Reverse Fan
10
:TO CHANGE VALUE
Use up and down keys to change the reversing time interval
24
The length of time the fan reverses can be varied through the Service Menu. From the Service Menu (not shown) select the Configuration Menu. From the Configuration Menu select the Parameter Settings Menu.
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Thermostat Housing
Coolant Expansion Tank
Coolant Temp Sensor
Intake Manifold Air Temperature Sensor
Coolant Bypass Tube Radiator
Visconic Fan Clutch Assembly
Cab Heater
To Cylinder Block
ATAAC
Top Tank
Text Reference Demand Fan Systems
Hottest
> 92 C
Increasing Coolant Temperature
87 C
Coldest
< 81 C
Engine Oil Cooler
Water Pump
Monitor
Slow Return Check Valve
Engine ECM
Machine ECM
CAN Data Link
Main Return Filter
CDL
OK
Hydraulic Oil Temp Sender
Hydraulic Circuits
320D-329D VISCONIC DEMAND FAN COOLING SYSTEM ENGINE AT OPERATING TEMPERATURE
25
VISCONIC DEMAND FAN SYSTEM (ATTACHMENT) The 320D-329D Hydraulic Excavators can be equipped with an electronically controlled, viscous coupled demand fan. The speed of the engine cooling fan is controlled by the Engine ECM in relation to engine coolant temperature, inlet manifold air temperature, and hydraulic fluid temperature. A viscous coupling fan clutch is used between the engine mounted, belt driven fan drive hub and the fan assembly. Inside the visconic coupling, a high viscosity, temperature stable, silicon fluid provides a means of coupling and uncoupling the fan to the fan input hub. When the machine is running, the hydraulic oil temperature sender and the engine coolant temperature sensor sends signals to the Engine ECM. The Engine ECM then sends this information to the Machine ECM. The Machine ECM picks up the hydraulic temperature through the monitor.
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Text Reference Demand Fan Systems
The Machine ECMs interpret the information from these inputs to send a PWM signal to the fan electronic control solenoid to control the demand fan clutch. A higher temperature input will the Machine ECM to send a reduced PWM signal to the fan electronic control solenoid. The reduced PWM signal causes the fan clutch to move toward full engagement to increase the fan speed for more cooling capacity. With the minimum PWM signal the fan will turn at the engine speed. NOTE: The following illustrations show the fan clutch is various stages of disassembly. These components are not serviced separately. The clutch is serviced only as a unit.
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Text Reference Demand Fan Systems
VISCONIC FAN DRIVE ASSEMBLY Reservoir
Valve Arm
Fill Hole
Cross Hole
Solenoid
Armature Blade Fluid Control Valve
Front Housing
Scavenge Hole
Input Plate
Silicon Oil Flow
Rear Housing
Working Chamber
Bearing
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The illustration above shows the flow path of the silicon fluid through the visconic fan drive assembly as well as identifies the major components. The components will be explained in more detail later in this presentation. The fan solenoid does not rotate with the fan blade or fan drive assembly. The fan is bolted to the fan drive assembly. The input plate is driven at engine speed. The silicon fluid flows from the fluid reservoir through the open fluid control valve and enters the working chamber through the fill hole. The silicon fluid travels through the concentric rings of the working chamber causing rotational force from the input plate to be transferred to the front and rear housings, which causes the fan to rotate. Depending on the amount of silicon oil in the working chamber, will determine how fast the fan turns. The centrifugal force of the rotating drive assembly causes the fluid to travel to the outside of the working chamber where small passages return the fluid back to the fluid reservoir.
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27 The upper left illustration shows the viscous fan drive clutch assembly as viewed from the radiator side. The fan electronic control (1) is pressed onto a bearing that is mounted to the radiator side (2) of the visconic drive clutch assembly. The illustration at the upper right shows the fan electronic control removed from the mounting bearing (2) on the fan drive assembly reservoir cover (3). Visible near the center of the electronic fan control is the Hall Effect type speed sensor (4). A ring magnet and bolt (5) are installed in the center of the fan drive front housing. The magnet and bolt are fixed to the main aluminum body and rotate at the same speed as the fan drive assembly. The ring magnet and bolt components produce six pulses per revolution of the fan drive assembly relative to the stationary Hall effect speed sensor. The Hall effect sensor produces a square wave speed signal as the six points of the bolt head rotate within the electronic control.
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Text Reference Demand Fan Systems
The fan fluid control valve and armature (6) and the fluid reservoir chamber (7) can be seen in the lower left illustration. The fan fluid control valve is part of the reservoir cover and the fluid reservoir chamber is part of the front (fan side) housing (8). The lower right illustration shows the rear (engine side), housing assembly (9) of the viscous drive and the front (fan side) housing (8) (flipped over). A series of concentric rings in each drive housing form the fluid paths of the visconic drive.
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The engine side fan drive housing assembly consists of rear (or engine side) housing (1) and an input plate (2), which is pressed onto the input hub shaft (3). The concentric rings (4) machined into the input plate nearly fill the space (5) (red circle) between the concentric rings of the front and rear housings. (The front housing concentric rings are not shown). A high viscosity silicon fluid is used to fill the gaps between the concentric rings and provides the rotational torque (internal drag) needed to turn the fan blade. The close tolerance of the concentric rings and the high viscosity of the silicon fluid act similar to the turbine and impeller sections of most torque converters. The rotation of the input plate provides a rotating force to the front and rear drive housings.
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Text Reference Demand Fan Systems
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An electro-magnetic rotary fluid control valve is used to control the flow of the visconic fluid within the visconic drive assembly. The electro-magnetic valve is part of the aluminum fluid reservoir chamber cover (1) in the front drive housing. The upper illustration shows the fluid valve in the closed (default) position. The steel electro-magnetic fluid valve armature (2) rotates within the fluid reservoir cover. Maximum rotation of the armature is controlled by the stop pin (3) pressed into the cover. A return spring (4) is used to keep the armature in the closed (default) position. A stainless steel valve arm (5) opens or closes the large fluid passage in the fluid reservoir depending on the position of the fluid valve armature.
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Text Reference Demand Fan Systems
Eight iron bars (6) are cast into each of the castelations of the aluminum reservoir cover. These iron bars act as "opposite poles" to the electro-magnetic fluid control valve armature when a magnetic flux is applied to the armature by the fan control coil.
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Text Reference Demand Fan Systems
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The front (radiator side) housing contains the fluid reservoir chamber and has two fluid passages leading to the working chamber of the visconic drive. The large passage (1) is opened or closed by the movement of the fluid control valve armature. As the valve armature moves, the valve arm will open or close to allow fluid to the working chamber below the reservoir. By opening the large passage, more fluid will flow to the working chamber of the visconic drive, and more rotational torque is transferred from the input plate to the front and rear drive housings. With the working chamber filled with fluid, the fan will spin at nearly the speed of the input hub. The small passage (2) allows the visconic fluid to flow from the working chamber back to the reservoir. NOTE: There are two fluid drain passages from the working chamber to the fluid reservoir. Only one drain passage can be seen in the above illustration.
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Text Reference Demand Fan Systems
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This illustration shows the inner (working chamber) side of the front housing. The fluid inlet passage (1) from the reservoir allows fluid to enter the working chamber. Centrifugal force of the rotating fan drive will cause the fluid to travel outward from the center of the housing and fill the passages of the working chamber. The small fluid return passages (2) constantly drain the working chamber back to the fluid reservoir. To reduce the fan speed the Engine ECM will increase the current to the coil of the electronic control and the increased flux will cause the control valve to rotate against the return spring and close the large fluid passage. When the large fluid passage is closed by the fluid control valve, the remaining fluid in the working chamber will drain back to the reservoir through the small drain passages and the fan speed will decrease.
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Text Reference Demand Fan Systems
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The above illustration shows the electrical control coil (1) and the Hall Effect speed sensor (2) of the fan control. The electronic control coil (shown here installed upside down) is pressed onto a bearing (not visible) on the fluid reservoir cover (3). The Engine ECM supplies a variable current to the electrical coil. The strength of the electrical current increases or decreases the strength of the flux on the rotary fluid control valve. A high current will induce a strong magnet flux through the rotary fluid valve armature and cause it to rotate to the closed position. The Hall Effect speed sensor uses the six points of the hexagon head retaining bolt (4) as a reluctor. The retaining bolt spins at fan blade speed while the electronic control coil remains stationary. The bolt heads provide six pulses to the Hall Effect sensor for each revolution of the fan hub. The square wave output signal from the Hall Effect sensor is monitored by the Engine ECM to determine fan speed.
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Text Reference Demand Fan Systems
Intake Manifold Air Temperature Sensor
Coolant Temp Sensor Monitor
VISCONIC DEMAND FAN OPERATION
Engine ECM
Machine ECM CAN Data Link
Clutch Working Chamber
CDL OK
Housing Hydraulic Oil Temp Sender
Valve Arm
OPEN STATE
Fan Electronic Control Solenoid
Pin
Valve Arm Reservoir Cover
Radiator Spring Armature Blade
Bars
Fan Fluid Control Valve
Armature Blades
Fluid Reservoir
Bearing
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The intake manifold air temperature sensor and the coolant temperature sensor are inputs into the Engine ECM. The Engine ECM provides information to the Machine ECM from these two sensors. The Machine ECM also receives information from hydraulic temperature sensor through the monitor. Based on the values of these sensors the Machine ECM will vary the amount of current to the fan electronic control coil. As the current to the fan control coil is increased, increased magnetic flux produces a rotational movement to the fluid control valve armature. As the fluid control valve rotates, the valve arm closes the large hole in the fluid reservoir allowing less fluid to flow into the working chamber of the visconic fan clutch. The increase in magnetic flux to the fluid valve armature causes the armature to rotate as the outer blades of the armature try to align with the steel bars in the reservoir cover. The spring under the fluid valve armature opposes the rotation of the armature and counter balances the armature's rotation.
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Text Reference Demand Fan Systems
As the armature rotates towards the steel bars, the stainless steel valve arm closes the large fluid passage in the fluid reservoir of the front housing. Completely closing the fluid passage in the front cover will allow a minimum amount of the visconic fluid to flow into the working chamber of the drive assembly and minimum fan speed. If a low or no current condition is present in the fan electronic control, the armature return spring will rotate the armature blades away from the steel bars and the valve arm will open the large passage of the fluid reservoir resulting in maximum fan speed. A fan speed map within the software of the Engine ECM will compare temperature sensor readings with the desired fan speed map and plot target fan speed according to engine rpm and current fan speed. If only one sensor is reporting a high temperature, or need for increased cooling, the ECM will reduce the current to the fan control coil by a predetermined percentage of the fan speed map and the fan speed will increase. The Engine ECM monitors the speed of the fan blade by use of a Hall Effect type sensor built into the center of the electronic fan control. A ring magnet and bolt is installed in the drive assembly at the center of the fan control coil. The ring magnet and bolt will rotate at fan speed and provide an input to the speed sensor. The fan speed sensor is supplied with a 5 volt reference signal and returns a square wave frequency signal to the Engine ECM. If no fan speed signal is supplied to the Engine ECM by the fan speed sensor the fan will default to maximum fan speed.
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Cat ET Screens for the Visconic Cooling Demand Fan Using Cat ET, the status of the fan control system can be monitored. The system status information can be helpful when troubleshooting the cooling system. NOTE: The 320D-329D excavators are not currently available with a reversing fan. The reversing fan solenoid parameter should always show as not installed.
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Text Reference Demand Fan Systems
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After connecting Cat ET, go to the configuration screens. Under Machine Control, open up the Machine Attachments parameters to view the four cooling fan parameters. The Engine Cooling Map parameter can be changed on all machines. This parameter does require special factory passwords in order to change the parameter. NOTE: The 320D-329D excavators are not currently available with a reversing fan. The parameters related to the reversing fan should be disregarded.
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Text Reference Demand Fan Systems
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Through Cat ET, one of four different cooling fan maps can be selected. From the factory the 320D-329D machines for NACD are only and should ONLY be configured to High Ambient. 330D/336D machines for EAME are configured to High Ambient Temperature + Low Noise and ISJ machines are configured to Standard + Low Noise. The Standard cooling map is currently not being used by any of the factories. Factory passwords are required to change the cooling fan map. NOTE: The technician should never be required to change the cooling map. This parameter is for factory use only.
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Text Reference Demand Fan Systems
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To obtain factory passwords go to https://fps.cat.com. NOTE: The passwords above will only work with the machine serial number shown.
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Text Reference Demand Fan Systems
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On the Override Parameter screen there are three cooling fan parameters that can be overridden. Parameter overrides can be used to perform various system tests that may or not be found in the Service Manual. NOTE: The 320D-329D excavators are not currently available with a reversing fan. The parameter related to the reversing fan solenoid should be disregarded.
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Text Reference Demand Fan Systems
320D - 329D MONITOR DEMAND FAN SCREENS Service Menu 12:01 SERVICE
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ECM INFO STATUS CALIBRATIONS DEVICE TEST OVERRIDE CONFIGURATIONS PRESS OK TO PERFORM OVERRIDE
Fan Overrides 12:01 OVERRIDE
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DESIRED ENG SPEED 9 5 0.0 [RPM] FAN MOTOR SPEED 5 8 3.0 [RPM] FAN MOTOR CUR PERCENT 0.0 [ % ] PRESS
TO CHANGE DATA
OK
Fan Calibration 12:01 FAN SPEED
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00 : FAILED ERROR ID :
$ 000B
PRESS L TO GO BACK TO UPPER LAYER SCREEN
: OVERRIDE OFF : MOVE CURSOR
Non-functional
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Monitor Screens for the Visconic Cooling Demand Fan From the Service sub-menu the Override sub-menu and the Calibration sub-menu can be displayed. In the Override screen, overrides for the fan can be selected. The two fan motor overrides are used to perform system tests. These tests may or may not be covered in the service manual. From the Calibration sub-menu, fan calibrations can be selected. Visconic fan calibration is currently non-functional.
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Text Reference Demand Fan Systems
41 CONCLUSION This presentation has provided information for the 300D Series Caterpillar Hydraulic Excavators. This section of the presentation covered the demand fans for the engine cooling systems. When used in conjunction with the service manual, the information in this package should permit the technician to do a thorough job of analyzing a problem in these systems. For service repairs, adjustments, and maintenance, always refer to the Operation and Maintenance Manual, Service Manuals, and other related service publications.
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