TECHNICAL PRESENTATION
D8T TRACK-TYPE TRACTOR
Meeting Guide 789
(STMG)
diagnostic equipment, and procedures for testing and adjusting.
CONTENT
This presentation discusses the operation of the power train, the differential steering system, the implement hydraulic system, the demand fan and the cooling systems, and the Caterpillar Monitoring and Display System with Advisor™ on the D8T Track-type Tractor. Also discussed is the operation of the controls in the operator compartment and the location and identification of the major components of the C15 ACERT™ technology engine.
OBJECTIVES
After learning the information in this presentation, the serviceman will be able to: 1. locate and identify all of the major machine components;
2. locate and identify all filters, dipsticks, indicators, fill tubes, drains and test points; 3. locate and identify the major components of the C15 ACERT™ technology engine and
trace the flow of fuel through the C15 engine fuel delivery system; 4. trace the flow of air through the engine's air intake system;
5. trace the flow of coolant through the cooling system of the D8T;
6. identify and explain the function/operation of each component in the hydraulic demand fan system;
7. trace the flow of oil through the hydraulic demand fan system;
8. identify and explain the function/operation of each component in the power train system; 9. trace the flow of oil through the power train hydraulic system;
10. identify and explain the function/operation of each component in the steering hydraulic system;
11. trace the flow of oil through the steering hydraulic system;
12. explain the function/operation of each component in the implement hydraulic system; 13. trace the flow of oil through the implement hydraulic system; and
14. locate and identify all the major components in the Caterpillar Monitoring and Display System, with Advisor.
REFERENCES
Engine Systems Operation, Testing & Adjusting (C15 &C18 Engine) . . . .SENR9382 Engine Troubleshooting Guide (C15 &C18 Engine) . . . .SENR9748 Systems Operation, Testing & Adjusting (Power Train) . . . .RENR7526 Systems Operation, Testing & Adjusting (Hydraulic System) . . . .RENR7527 Systems Operation, Testing & Adjusting (Cooling Systems) . . . .RENR8197 Schematic (Hydraulic System) . . . .RENR7528 Schematic (Electrical) . . . .RENR7530
PREREQUISITES
Interactive Video Course "Fundamentals of Mobile Hydraulics" . . . .TEMV9001 Interactive Video Course "Fundamentals of Electrical Systems" . . . .TEMV9002 STMG 546 "Graphic Fluid Power Symbols . . . .SESV1546
SUPPLEMENTARY TRAINING MATERIALS
D8T Track-type Tractor - New Product Introduction (NPI) . . . .SERV7104-09 STMG 790 "Caterpillar Monitoring and Display System, with Advisor" . . . .SERV1790 STMG 736 "D8R Series II Track-type Tractor" . . . .SESV1736 STMG 633 "D8N Track-type Tractor - Two Pump Hydraulic System" . . . .SERV1633 STMG 547 "Track-type tractor - Power Train and Implements" . . . .SERV1547 Technical Instruction Module "Air Conditioning Principles and Operation" . . . .SEGV2580 CD ROM version of SEGV2580 . . . .SERV2580 Technical Instruction Module "Air Conditioning Service Procedures" . . . .SERV2581
Estimated Time: 6 Hours Visuals: 145 Slides
Serviceman Handouts: 5 Lab Exercises Form: SERV1789
OPERATOR'S COMPARTMENT...6
CATERPILLAR MONITORING AND DISPLAY SYSTEM WITH ADVISOR™ ...21
Start Up ...28
ENGINE...33
Fuel System...52
Engine Air System ...53
Cooling System...54
Hydraulic Demand Fan System ...58
POWER TRAIN ...66
Power Train Electronic Control System ...67
Power Train Hydraulic System ...68
Torque Divider ...75
Power Shift Transmission ...84
Electronic Brake Control Valve ...90
DIFFERENTIAL STEER MECHANICAL OPERATION ...101
Differential Steering System Operation...103
IMPLEMENT HYDRAULIC SYSTEM ...118
Implement System Operation ...129
Implement Pump Operation...131
Implement Control Valve operation...142
Dual Tilt Operation ...153
Quick-drop Valve ...159
AutoCarry Components ...166
CONCLUSION...173
HYDRAULIC SCHEMATIC COLOR CODE...174
VISUAL LIST ...175
INTRODUCTION
This presentation discusses the major design features and changes, the component locations and identifications, and the systems operation of the D8T Track-type Tractor. The D8T appearance is similar to the D8R Series II. The operator station incorporates the common cab, which is also used for the D9T, and the D10T Track-type Tractors.
The D8T is powered by the C15 ACERT™ (Advanced Combustion Emissions Reduction Technology) electronic engine equipped with the Mechanical Electronic Unit Injection (MEUI) fuel system. This engine also utilizes the A4 ECM engine control and is equipped with an Air To Air AfterCooler (ATAAC) intake air cooling system. The C15 is an in-line six-cylinder arrangement and is rated at 231.6 net kW (310 net horsepower) at 1850 rpm.
Other standard features include: power train hydraulic system with a common top pressure strategy and remote pressure test ports, an electro-hydraulic demand fan, electro-hydraulic steering, an electro-hydraulic implement system with easily accessible components, the Advanced MOdular Cooling System (AMOCS) radiator, and the new Caterpillar Monitoring and Display System with Advisor™.
The D8T can also be equipped with optional attachments such as an engine pre-lubrication system, a cold-start package, a reversing fan, dual tilt blade controls with the Automatic Blade Assist (ABA) feature, and AutoCarry. The D8T can be ordered ready to accept the Computer Aided Earthmoving System (CAES) and the AccuGrade system.
The serial number prefix for the D8T is KPZ, for machines built in the U.S. The serial number prefix for the D8T built in Brazil is J8B.
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D8T TRACK-TYPE TRACT
D8T TRACK-TYPE TRACT
OR
OR
© 2004 Caterpillar Inc. © 2004 Caterpillar Inc.
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OPERATOR'S COMPARTMENT
The operator's compartment for the D8T incorporates the "Common Cab," which is used on the D8T, the D9T, and the D10T Track-type Tractors. The cab is eight inches wider than the cab used for previous models. The cab has wider doors that open 20° further for easier entry and exit. It contains more glass area for better overall visibility for the operator.
Included in the new cab design is:
- the Caterpillar Monitoring and Display System with Advisor;
- a new dash with an automotive style sealed instrument cluster;
- a new right-hand console with redesigned controls for lighting and other machine systems; and
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The Cat contour seat is standard equipment, with air suspension available as an attachment. The seat provides maximum comfort and less operator fatigue. The operator can adjust the seat height, the front to rear seat position and tilt, and the seat back angle. The seat is angled 15° to the right in order to provide maximum visibility of implement operation.
The padded left armrest is manually adjustable for height using the two knobs (1) below the armrest The padded right armrest is similarly adjustable. Padded knee braces (2) provide operator comfort when operating the machine on side slopes.
The back and seat cushion assembly can be removed from the suspension base by removing one 8mm bolt (3), located on the lower front, center of the seat.
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Forward of the left armrest is the steering control lever, or tiller (1). The steering tiller combines steering, directional changes, and gear selection into one control. When pulled up, the parking brake switch (2) shifts the transmission to FIRST gear NEUTRAL and energizes the parking brake and secondary brake solenoids on the electronic brake valve, which engages the brakes. The parking brake switch also electronically disables the steering system and mechanically locks the tiller housing.
FORWARD, NEUTRAL, and REVERSE are controlled by rotating the tiller hand grip (3). All three positions have detents that hold the tiller in the selected position. A PWM rotary position sensor connected to the hand grip provides a signal to the Power Train ECM when the handgrip is rotated. In addition, a forward switch and a reverse switch are also used to signal the Power Train ECM and confirm the hand grip position. The Power Train ECM then sends a
corresponding signal to the appropriate transmission modulating solenoid valves to engage and disengage the forward and reverse clutches in the transmission.
The top yellow button (4) upshifts the transmission one gear range at a time, and the bottom yellow button (5) downshifts the transmission one gear range at a time.
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Left turns are accomplished by rotating the tiller (1) toward the front. Right turns are accomplished by rotating the tiller toward the rear. When the operator releases the tiller, a centering spring returns the tiller to the center (NO STEER) position. Three PWM rotary position sensors (triple redundant) are attached to the tiller shaft and send electronic signals to the Power Train ECM regarding the tiller's position. The Power Train ECM sends a
corresponding signal to the left or right proportional solenoid valves that control the steering pump.
NOTE: The differential steering strategy still incorporates the standard "S-Turn" logic used in
previous differential steer machines.
NOTE: When the parking brake is engaged, the secondary brake solenoid is also energized, as
a backup measure.
With the engine running and the transmission shifted to NEUTRAL, rotating the steering tiller toward the front or the rear will cause the machine to steer. The tracks will counter-rotate, resulting in the machine pivoting about its center point. To avoid personal injury and/or property damage, always ENGAGE the parking brake when not operating the machine and when other personnel are nearby.
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The right console contains the implement controls and most of the controls and switches for machine systems and functions. The dozer control lever (1) allows the operator to control all of the blade functions with one lever.
To the rear of the dozer control lever is the ripper control handle (2). The ripper control handle allows the operator to control all of the ripper functions. If the machine is equipped with a winch, the winch control would be located in this same position.
Located to the rear of the ripper handle and on the vertical panel of the right console is the rear action lamp (3), which alerts the operator of a machine system that is operating out of its normal range. Just forward of the action lamp is a 12-volt switched power adapter (4).
To the right of the dozer control lever is the forward horn button (5).
On the vertical panel and above the forward horn button, is the key start switch (6).
Ahead of the dozer control lever is the Cat Advisor™ graphical display module (7), which will be discussed in greater detail, later in this presentation.
The Machine Security System (MSS) indicator light (8) is located below the Advisor panel.
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The dozer control lever (1) allows the operator to control all of the blade functions with one lever. When the lever is moved FORWARD, the blade will LOWER. Moving the lever forward to a point within 3°- 4° of the soft FLOAT detent causes the quick-drop valve to activate.
Moving the lever completely forward to the soft FLOAT detent activates the FLOAT function. The lever will return to the centered position and maintain the FLOAT function. Moving the lever either forward or rearward from the centered position will deactivate the FLOAT function. Moving the lever to the rear of the center (HOLD) position causes the blade to RAISE. Moving the dozer control lever to the right tilts the right side of the blade down. Moving the lever to the left tilts the left side of the blade down.
If the machine is equipped with dual tilt, moving the thumb lever (2) to the right allows the operator to DUMP the blade (PITCH FORWARD). Moving the thumb lever to the left will RACK BACK the blade.
The left yellow button (3) allows the operator to activate segments in the Auto Blade Assist (ABA) cycle and/or the AutoCarry cycle, if the machine is equipped with ABA or AutoCarry. The right yellow button (4) cancels the ABA or AutoCarry cycle. The blade may be controlled manually at any time during the ABA or AutoCarry cycles.
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The left rocker switch (5) on the panel ahead of the dozer control lever, and below the Advisor panel is the ABA switch. It is used to arm the ABA mode. All of the Auto Blade Pitch settings for LOAD, CARRY, and SPREAD may be configured using Cat Advisor.
The right rocker switch (6) manually activates the fan reversing cycle, if the machine is equipped with a reversing fan.
NOTE: There are three different dozer control levers that can be installed in the D8T,
depending on how the machine is equipped.
The dozer control lever shown in illustration 6 is used on machines that are equipped with dual tilt. Machines equipped with dual tilt also include the ABA feature.
If the machine is not equipped with dual tilt, but is equipped with AutoCarry, the control lever will look the same, but the thumb rocker switch is not active.
If the machine has neither dual tilt nor AutoCarry (standard single tilt machine), the dozer control lever will not include the thumb rocker switch or the two yellow buttons.
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To the rear of the dozer control lever is the ripper control handle (1). Pulling back on the left side of the finger switch (2) moves the tip of the ripper SHANK IN. Pulling back on the right side of the finger switch moves the tip of the ripper SHANK OUT.
At the left of the ripper control handle is the thumb switch (3), which controls RIPPER RAISE and RIPPER LOWER. Pushing against the top of the thumb switch RAISES the ripper. Pushing against the bottom of the thumb switch LOWERS the ripper.
Pushing the Auto-Stow button (4) raises the ripper to the maximum height and can move the ripper tip to the full SHANK IN or full SHANK OUT position, depending on the operator settings configured using Cat Advisor. There are three Auto-Stow positions that may be configured: RIPPER RAISE, RIPPER RAISE/SHANK IN, or RIPPER RAISE/SHANK OUT.
If the machine were equipped with a winch, the winch controls would be located in this same position. The winch control is similar to that used on the current D8R Series II Track-type Tractor, except that the drum clutch disconnect position has no detent.
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The panel on the outside of the right console contains a number of switches that control various machine functions. To the immediate right of the key switch is the High/Low Idle switch (1).
Just above the High/Low Idle switch is the Implement Lockout switch (2), which disables implement movement and illuminates the Implement Lockout indicator light in the instrument cluster, when activated. Activating the Implement Lockout switch de-energizes the implement lockout solenoid, which shuts off the flow of pilot oil to the implement control valves. With no pilot oil available to the implement control valves, the implements cannot move.
The AutoShift Mode switch (3) activates the AutoShift mode. The AutoShift mode may be configured using Cat Advisor, or by using Caterpillar ®Electronic Technician (Cat ET).
The Auto KickDown Mode switch (4) enables the Auto KickDown mode, when activated. Shift-point sensitivity for the Auto KickDown mode (Low, Medium, and High) may be configured using Cat Advisor, or by using Cat ET.
If the machine is equipped with AutoCarry, the AutoCarry Mode switch (5) arms the AutoCarry mode when activated.
The ripper pin puller switch (6) is used to automatically retract and extend the ripper shank pin, if the machine is equipped with a single shank ripper.
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Located at the bottom front of the left console, and just inside the left cab door is the main fuse panel, circuit breakers, and diagnostic connector. Opening the hinged door gains access to:
1. the air conditioning remote condenser circuit breaker (if equipped - not shown, above) 2. the HVAC blower motor circuit breaker
3. the diagnostic connector for the Cat ET
4. the 12 volt switched power supply (for powering a laptop computer or other devices) 5. the 175 amp alternator fuse
6. the main electrical fuse panel, using automotive type fuses
A fuse and breaker identification chart (7) is affixed to the inside of the hinged door. The chart shows fuse locations and identifies their associated electrical circuits.
Several spare fuses, a spare 175 amp alternator fuse, and a fuse puller tool are also stored inside the hinged door.
NOTE: The hinge on the door is spring loaded so that the door may be completely
removed, if necessary.
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The HVAC controls and the wiper/washer controls are located overhead, above the right console. From left to right, these controls are:
1. HVAC blower fan speed switch, with four fan speed positions
2. HVAC temperature control
3. air-conditioning selector switch (ON/OFF)
4. front windshield wiper/washer control switch
5. left cab door wiper/washer control switch
6. right cab door wiper/washer control switch
7. rear cab window wiper/washer control switch
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The dash in the new cab contains an automotive style instrument cluster, which replaces the quad gauge module and the main display module with mode/alert indicators of the previous Caterpillar Monitoring System. The instrument cluster is a sealed unit that contains the following four analog gauges:
1. hydraulic oil temperature gauge 2. engine coolant temperature gauge 3. torque converter oil temperature gauge 4. fuel level gauge
Also included in the instrument cluster is the tachometer (5) and up to fifteen indicator lights that alert the operator of different operational modes or conditions.
The LCD display (6) below the tachometer displays the service hours at the bottom of the display, the track speed at the upper left, and the selected transmission gear and direction at the upper right.
INSTRUCTOR NOTE: The instrument cluster and new monitoring system will be
discussed in more detail, later in this presentation.
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Below the dash are the service brake pedal (1) and the decelerator pedal (2). The service brake pedal applies the service brakes (both left and right) proportionately with the amount of pressure applied by the operator. When depressed, the pedal provides a signal to the Power Train ECM from the rotary position sensor connected to the pedal. The Power Train ECM then signals the electronically controlled brake valve. When completely depressed, the brakes are fully engaged.
The smaller pedal on the right is the decelerator pedal. During normal operation, the machine operates at high idle. Depressing the decelerator pedal decreases the engine rpm by a signal to the Engine ECM from the rotary position sensor connected to the pedal.
Intermediate engine speeds are attained in the following manner. First, set the high/low idle switch to the HIGH IDLE position, and then depress the decelerator pedal to the desired engine speed. Then, press and hold the high idle (rabbit) side of the high/low idle switch for
approximately three seconds and then release the switch to set the intermediate engine speed. The engine speed may then be reduced from this intermediate engine speed by depressing the decelerator pedal. When the decelerator pedal is released, the engine speed will return to the intermediate setting. The intermediate engine speed setting may be cancelled by pressing either the high idle (rabbit) or low idle (turtle) side of the switch again.
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The Power Train ECM (1) and the Implement ECM (2) are located at the rear of the cab. Accessing the Power Train ECM can be accomplished by removing the operator seat and the sound panel at the rear of the cab. The sound panel under the right console must also be removed to gain access to the Implement ECM. Other components located here are:
3. the J1/P1 connector for the Implement ECM
4. the J2/P2 connector for the Implement ECM
5. the J1/P1 connector for the Power Train ECM
6. the J2/P2 connector for the Power Train ECM
7. the exterior lighting relays
NOTE: The Implement ECM and Power Train ECM code plugs are tied to the wiring
harness, below the ECMs.
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CATERPILLAR MONITORING AND DISPLAY SYSTEM, WITH ADVISOR™ The monitoring system for the D8T has been upgraded to the Caterpillar Monitoring and Display System with Advisor.
The major components in the new monitoring system consist of the Advisor graphical display module (1) and the in-dash instrument cluster (2). The graphical display module has a self-contained ECM (Advisor ECM).
Advisor allows the operator to configure machine and implement operation and the display options, then save them to an operator profile that may be selected whenever the operator desires.
Advisor also allows the serviceman to configure certain password protected machine functions and to view system status information for the engine, the power train, the steering, and the implement systems. The serviceman can also perform calibrations of the machine and
implement controls, the brakes and transmission, and the steering system through the Advisor panel.
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The Caterpillar Monitoring and Display System (CMDS) continuously monitors all machine systems. CMDS consists of both software and hardware components. The hardware
components consist of the Cat Advisor graphical display module, a sealed instrument cluster, the Engine ECM, the Implement ECM, the Power Train ECM, the Action Alarm, the rear Action Lamp, and various switches, sensors, and senders. If the machine is so equipped, the CMDS may also include connections to a Product Link ECM, a Computer Aided Earthmoving System (CAES), and the Accugrade system and its components.
The CMDS components communicate with each other and with electronic controls on the machine’s components through the Cat Data Link and through Controller Area Network (CAN) Data Links. A machine with standard equipment uses the Cat Data Link, the CAN A Data Link, and the CAN C Data Link. With AutoCarry attachments, CMDS will also include a CAN B Data Link (shown in dashed lines, above) and a CAN D Data Link (not shown, above).
Advisor constantly monitors all of the ECMs, the alternator R-Terminal, the system input voltage, and the fuel level sensor, or sender. Advisor transmits the monitored data to the instrument cluster and activates its mode and alert indicators, displays, and gauges. This information may also be accessed and displayed on Advisor’s screens or with Cat ET.
Dynamic Inclination
Sensor
Fuel Level Sender
CAN A Data Link Engine ECM Implement ECM Power Train ECM J2 J1 Switch J2 J1 Advisor
ET
CAN C Data Link CAN A Data Link(
)
Navigator / CTCT Attachments RearAction Lamp Action Alarm
Instrument Cluster CAT Data Link
CAN B
Data Link Comm
Adapter II Alternator (R-Terminal) Product Link AUTO AUTO 0 5 10 15 20 25 30 35 n/ minX100 2.3 1F 132.1 J2 J1
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In addition to the four analog gauges, the tachometer, and the LCD display screen (mentioned earlier), the instrument cluster contains up to fifteen LED indicators that show the operator the status of a number of machine functions. When lit, they indicate the following functions:
1. Engine pre-lube activated (illuminates only if equipped with a pre-lube system) 2. winch disabled (illuminates only if the machine is equipped with a winch) 3. winch low speed lock (illuminates only if the machine is equipped with a winch) 4. winch freespool or release (illuminates only if the machine is equipped with a winch) 5. Auto KickDown activated
6. AutoShift activated 7. parking brake ON 8. Action Lamp
9. charging system fault (abnormal output at the "R" terminal)
10. Auto Blade Assist enabled (illuminates only if the machine is equipped with ABA) 11. AutoCarry active (illuminates only if the machine is equipped with AutoCarry) 12. implement lockout activated
13. FLOAT active 14. single tilt enabled
15. dual tilt enabled (illuminates only if the machine is equipped with dual tilt) AUTO AUTO 0 5 10 15 20 25 30 35 n/minX100 Implement Lockout Activated (12) AutoCarry Active (11) Charging System Fault (9) Parking Brake On (7) ABA Enabled (10) Action Lamp (8) Winch Disabled (2) Dual Tilt Enabled (15) Single Tilt Enabled (14) Float Active (13) Winch Low Speed Lock (3) Winch Freespool or Release (4) AutoShift Activated (6) Auto KickDown Activated (5) Not Used
2.3 1F
132.1
Engine Pre-Lube Activated (1) Not UsedINSTRUMENT CLUSTER
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The heart of the CMDS is the graphical display module, which is located on the right console, ahead of the dozer control lever. The graphical display module is referred to as Advisor.
Advisor consists of the display screen (1), the navigational buttons (2), and an internal, self-contained ECM (not visible).
Advisor is used to access, monitor, and display operating characteristics, diagnostics and events, and modes of operation. Advisor is also used to view and change operator preferences and parameters, much like the Vital Information Display System (VIDS) in the previous D10R Track-type Tractors.
Advisor also allows the serviceman to troubleshoot and adjust machine systems by:
- viewing active and logged codes and events, and clearing logged codes;
- viewing the status of machine systems and their components;
- and performing calibrations for the steering, the implement, and the power train systems.
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Cat Advisor is the interface between the operator or serviceman and the CMDS. Information is displayed on a backlit LCD screen.
The top portion of the screen is called the "Top Banner" and it displays vital machine
information at all times. The Top Banner may display different information from machine to machine, depending on the attachments and the machine configuration. On the base machine, the banner displays:
- Transmission Gear and Direction, at the left; - Dozer Mode, in the center;
- AutoShift Mode, at the right.
The Transmission Gear and Direction display area shows the transmission gear and direction that is currently selected. The display may show any of the following transmission gear and direction combinations: "1F, 2F, 3F, 1R, 2R, 3R, or 1N."
OK
1F 1F-2R
Service Home MenuFloat
Operator Performance Settings Gear/Direction
Display Area Display AreaDozer Mode Auto-Shift ModeDisplay Area
(1) Left / Up Arrow Button
(2) Right / Down Arrow Button
(3) Back Button
(Delete / Backspace Button)
(4) Home Button
(5) OK Button
(Enter / Select Button) Data Display / Menu Selection
Display Area "More Options" Icon
- Carry (CARRY segment active - blade is in CARRY position)
- Spread (blade is moving from CARRY to a preset SPREAD position) - Ready To Return (blade is at end of SPREAD segment - gear is Neutral) - Return (blade has reset - not in Forward gear)
- Ready To Carry (blade is loading, next move will position for CARRY) - Manual (Manual blade mode active - ABA or AutoCarry not armed) - Not Reset (ECM does not know blade position)
- Resetting (blade automatically moving to find load position)
- Float (blade is in FLOAT - dozer control lever is in FLOAT position) - Low Engine Speed (engine speed too low for ABA/AutoCarry modes) - Wrong Gear (wrong gear for AutoCarry mode - shift the transmission to 1F) - Service (displayed during implement calibrations)
- Implements Off (Implement Shutoff is ON, or active)
- Stowing Ripper (ripper moving to stow position - AutoStow activated)
The AutoShift Mode display area shows the current AutoShift Mode that is selected, using the AutoShift Mode selector switch on the right operator console. Depending on how the tractor is configured, it can display "1F-2R," "2F-2R," "2F-1R," or "Inactive," if no AutoShift Mode is selected.
The bottom portion of the Advisor display screen is the Data Display/Menu Selection Display Area. It displays numerous menus and sub-menus used for navigation from screen to screen. It may also display operator warnings, system information, and system status, depending on what menu or sub-menu selection has been made.
A "More Options" icon may also appear on the display screen. This is an indicator that more information is available for selecting or displaying from the current highlighted position. This icon may point down, up, left, or right. Using the Arrow Button that corresponds to the "More Options" icon will allow the operator or serviceman to move to and/or view the additional information.
At the right of the display screen is a column of five User Interface buttons. These buttons are used to navigate through the numerous Advisor screens, to make menu selections, or to enter data.
The five User Interface buttons, from top to bottom, are:
1. LEFT/UP Arrow button - This button is used for screen navigation or data entry. It can be used:
- to scroll up a vertical list or scroll left across a horizontal list; - to decrease a setting value, such as decreasing brightness/contrast.
2. DOWN/RIGHT Arrow button - This button is also used for screen navigation or data entry. It can be used:
- to scroll down a vertical list or scroll right across a horizontal list; - to increase a setting value, such as increasing brightness/contrast.
3. BACK button - This button is used:
- to go up one level in a stair-step (hierarchical) menu structure, or to return to the previous screen, much the same as the BACK Button is used in Windows Internet Explorer™;
- as a backspace, or cancel key when the operator or serviceman wishes to delete entered characters.
4. HOME button - This button is used to return to the home menu screen, regardless of what screen is currently displayed.
5. OK button - This button is used: - to make selections from a screen;
- to confirm an entry, such as a password, or for saving an operator profile entry.
Navigation through the menus and sub-menus is accomplished by using the ARROW buttons to highlight the desired selection, then pressing the OK button. The ARROW buttons are also used to highlight a mode or to set a parameter. Pressing the OK button selects that option. (Example: Choosing either "Enabled" or "Disabled" for the FLOAT option in the Implement Settings menu.)
NOTE: The column of five buttons at the left of the display screen currently have no
OK Recall Operator Settings
Display Setup OK OK OK Default Settings Activated in 10 Seconds Or Press To Recall Previous Settings Start Up
Advisor will perform a self-test routine at machine start-up (key ON). After a few seconds, a preliminary screen will appear (illustration 19). The preliminary screen displays, "Default Settings Activated in 10 Seconds Or Press OK To Recall Previous Settings." To use the operator profile (settings) that were active the last time the machine was operated the operator may acknowledge "YES" by pressing the OK button. NO is assumed by waiting 10 seconds.
If the operator answers YES by pressing the OK button, Advisor will load into its memory the operator profile that was last used.
If the operator waits 10 seconds, the default settings (or factory settings) will be loaded into Advisor's memory. If the operator wishes to use an operator profile (settings) other than the last used set or the default settings, another operator profile may be selected from the "Operator" menu selection, from the Home Menu (see the "Operator Option" section, later in this module).
After the preliminary screen has been acknowledged or has expired, "pop-up" warning screens may be displayed if there are any active faults in any of the machine systems (see illustration 20, next page).
OK 1F
Float
1F-2R Display Setup OK Engine ECM MID 36 ID 164-3Injection Actuation Pressure Sensor Voltage Above Normal Shorted High
ACKNOWLEDGE
PRESS THE OK KEY TO ACKNOWLEDGE
!
The illustration above shows a "pop-up" warning screen generated by the Engine ECM and reported by Advisor. There may be more warning screens if there are any other active faults or events reported to Advisor by the Engine ECM, or any other ECM on the machine. Advisor will scroll through all of the warning screens generated by all of the active faults and events. Each of these warning screens must be individually acknowledged by pressing the "OK" button.
Each of these warning screens contains the following information: - The reporting ECM (in text)
- The reporting MID (module identifier, or ECM code) - The ID (Component ID and Failure Mode Identifier) - A text message stating the failed component
- A text message stating the failure mode of the component - A prompt for the operator to acknowledge the warning
Acknowledging these warnings does not clear them from the reporting ECM's memory.
Acknowledging them only clears them from the screen, or "snoozes" them. They may re-occur after a pre-determined amount of time, depending on their severity.
The CMDS provides three Warning Category Indicators (levels), utilizing "pop-up" warning messages on Advisor's screen (see above), the front Action Light (contained in the instrument cluster), the rear Action Lamp, and an Action Alarm.
the event or diagnostic failure. The forward Action Lamp will illuminate to solid amber. The warning can be acknowledged (snoozed) by pressing the OK button, and will not re-appear for several hours, depending on the failure or event (or if the event or failure does not re-occur).
- Warning Category Indicator 2: A warning appears on the Advisor screen, describing the event or diagnostic failure. The Action Light and Lamp will flash red, alerting the operator to change the machine operation mode. The warning can be acknowledged (snoozed) by pressing the OK button, and will not re-appear for one hour, depending on the event or failure (or if the event or failure does not re-occur) and the Action Light and Lamp will stop flashing.
- Warning Category Indicator 3: A warning appears on the Advisor screen, describing the event or diagnostic failure. The Action Light and Lamp will flash red, and the Action Alarm will pulse to alert the operator to shut down the machine. The warning can be acknowledged (snoozed) and will continue to appear every five minutes. The Action Light and Lamp will continue to flash red and the Action Alarm will continue to pulse after the operator acknowledges the warning.
NOTE: If the Warning Category Indicator (fault) is related to an implement control
failure, the Advisor warning will ask if the operator desires to go to "Limp Home Mode." If the operator chooses the YES option, Advisor will display the Limp Home Screen. The Limp Home screen allows the operator to use Advisor to slowly and incrementally move the implements to a position that will allow the machine to be moved for service work. Gear selection for the transmission will be limited to first gear forward, or first gear reverse.
NOTE: At machine start-up (key ON), the LCD display in the Instrument Cluster will
briefly display the Instrument Cluster's part number. Although the T-Model tractors all have a common cab, the Instrument Cluster is different for the D8T, the D9T, and the D10T. This is due mainly because of differences in engine rpm between these models. The Advisor ECM software is model-specific also, reflecting the differences in
Instrument Clusters. The Instrument Cluster and the Advisor software must match for the Instrument Cluster to operate properly.
OK 1F 1F-2R Performance 1 of 2 87.8 C 1410 RPM 68.8 C 76.6 C Hydraulic Oil Temperature TCO Temperature Engine Speed Engine
Coolant Temp n/min
Next
Float
PERFORMANCE SCREEN 1 OF 2
OK 1F 1F-2R 506.0 kPa 40 C 26.3 Volts 75 %Fuel Level System
Voltage Air Inlet Temperature Engine Oil Pressure Performance 2 of 2
Float
PreviousPERFORMANCE SCREEN 2 OF 2
After the warning screens have been acknowledged the "Performance 1 of 2" screen will then appear on the display (illustration 21). This is the default screen. Pressing the right ARROW button will display the "Performance 2 of 2" screen (illustration 22).
Using the left and right ARROW buttons allows the operator to switch back and forth between the two Performance screens. Vital information about the machine's major systems may be easily monitored using these two screens and the in-dash Instrument Cluster.
21
- Hydraulic Oil Temperature
- Torque Converter Oil Temperature - Engine Oil Pressure
- Air Inlet Temperature - Fuel Level
- System Voltage
The Home Menu may displayed from any screen by pressing the HOME button.
INSTRUCTOR NOTE: For more detailed information about the new monitoring
system and Advisor and how to access and use all of the options, refer to SERV1790, "Caterpillar Monitoring and Display System with Advisor™ for Track-type Tractors."
23
ENGINE
The C15 ACERT™ technology engine is new for the D8T Track-type Tractor. The engine is equipped with Mechanical Electronic Unit Injection (MEUI), an Air To Air
AfterCooler (ATAAC), and a new electro-hydraulic demand fan system. The C15 engine also utilizes the A4 Engine Electronic Control Module (ECM), which is air cooled. The C15 is rated at 231.6 net kW (310 net horsepower) at 1850 rpm. The D8T uses a "constant net" power strategy. This means that at rated speed, and under full load, the tractor always delivers 231 kW (310 hp) at the flywheel, except during derates. When the demand fan is at maximum speed, the Engine ECM increases gross power to 259 kW (347 hp). At minimum fan speed, the Engine ECM maintains gross power at 243 kW (326 hp). This strategy maintains a constant net power regardless of fan requirements and provides fuel consumption benefits during low
ambient conditions.
The C15 engine is an in-line six-cylinder arrangement, with a displacement of 15.2 liters. Most of the service points for the C15 are located on the left side of the engine.
The C15 engine meets U.S. Environmental Protection Agency (EPA) Tier III Emissions Regulations for North America and Stage III European Emissions Regulations.
The C15 is functionally similar to the 3406E engine used in the D8R Series II. However, the Engine ECM and its software, the cam, the injectors, the crankshaft, the piston rods, the pistons, and a few other components are re-engineered, reflecting the change to ACERT technology. An electro-hydraulic demand fan is standard equipment for the D8T. The D8T may also be
equipped with an automatic/manual fan reversing feature for some applications.
The C15 ACERT technology engine specifications for the D8T Track-type Tractor are: -Serial No. Prefix: LHX
-Performance Spec: 0K4648 (for North America), and 0K4147 (for E.U.) -Max Altitude: 3810 m (12,500 ft.) without derate
-Gross Power: 259 kW (347 hp) -Net Power: 231 kW (310 hp) -Full Load rpm: 1850
-High Idle rpm (full throttle, neutral): 2200 ± 10 (for North America), 2070 ± 10 (for E.U.) -Low Idle rpm: 700
NOTE: The C15 engine uses a "Ground Speed Governor" engine software strategy to
reduce the potential for engine overspeed and to maintain a constant speed in downhill and uphill situations when there is little or no load on the blade. The Engine ECM constantly monitors engine speed and torque converter output speed to make the following adjustments.
- If the engine is at high idle while the machine is traveling downhill, the Engine ECM will automatically lower engine rpm to maintain the correct torque converter output speed. In uphill situations, the Engine ECM will automatically increase engine rpm to maintain the correct torque converter output speed, up to a maximum of 2200 rpm.
- If the engine is in an overspeed condition (2600+ engine rpms), the Power Train ECM will
automatically apply the brakes (up to 8% of brake capacity) in an effort to slow the machine. If this auto-braking strategy does not lower engine rpms to an acceptable level, Advisor will warn the operator to change the operating mode (downshift or manually apply the brakes).
- If the operator has set an intermediate engine speed using the decelerator and the
high-low idle switch, this strategy is ignored in uphill situations.
On machines built for the E.U., the torque converter output speed target is
approximately 5% lower than those built for North America, due to more stringent noise requirements. Accordingly, the ground speed target is a bit slower, also. This will result in slightly slower speeds when "roading" the machine and when backing up.
24
Major service points accessible from the left side of the engine are: 1. coolant sampling port (S•O•S)
2. engine oil fill tube
3. engine oil filter and associated service points (discussed later in this presentation) 4. air filter access cover
5. engine oil dipstick
6. primary fuel filter and water separator and electric fuel priming pump
7. secondary fuel filter and associated sensors (discussed later in this presentation) 8. A4 Engine ECM
9. starter
10. prelube motor and pump (if equipped)
11. high-speed oil change connectors for engine oil and power train oil
1 2 3 5 6 7 8 9 10 4 11
25
Major service points accessible from the right side of the engine are:
1. turbocharger
2. air conditioning compressor
3. thermostat (temperature regulator) housing 4. alternator
5. coolant flow switch 6. external engine oil cooler 7. power train oil cooler 8. block heater element
3 4 5 6 7 8
26
Located on the left side and toward the rear of the engine is the 10-micron primary fuel filter (1). The primary fuel filter contains a water separator which removes water from the fuel. Water in a high pressure fuel system can cause premature failure of the fuel injectors due to lack of
lubricity and corrosion.
Fuel is drawn from the primary fuel filter by the fuel pump (shown later) and is then returned to the 2-micron secondary fuel filter (2). The secondary fuel filter removes all contaminants that could damage the fuel injectors. Fuel filters should be replaced regularly, according to the guidelines on the D8T Operation and Maintenance Manual (SEBU7763) to ensure that clean fuel is always delivered to the fuel injectors.
The electric fuel priming pump (4) is integrated into the primary fuel filter base. It is activated by pushing the electric fuel priming pump switch (5). Also shown is the fuel system air purge valve (3), which is used to purge the priming pump of any air that might be introduced after changing the fuel filters. The fuel priming pump is used to fill the fuel filter housings after the filter elements have been replaced. The fuel priming pump is capable of forcing the air from the entire fuel system.
After the fuel filters have been replaced, activate the priming pump and then open the air purge valve. (Always place a suitable container under the purge valve outlet to catch any fuel that escapes through the valve.)
1 2 4 5 6 7 3 8 9
produces enough pressure to force fuel past the bypass valve in the fuel transfer pump and past the fuel pressure regulator (check valve). Also note that the main disconnect switch must be turned to the ON position and the key start switch must be in the OFF position for the fuel priming pump to run.
Also visible in the illustration above is the block heater receptacle (6). 120V and 240V versions of the block heater are available.
Also shown is the auxiliary start receptacle (7), which may be used to supplement the batteries when the temperatures are extremely cold or the batteries are low.
The ether aid solenoid (8) is also shown in illustration 26 (the ether canister is not installed). When the ether aid solenoid is energized, ether is injected into the intake manifold inlet tube (9). The Engine ECM controls ether injection when the conditions warrant its use. The Engine ECM monitors the intake air temperature sensor and the coolant temperature sensor to determine when to inject ether. If the temperature of the engine coolant or the intake air is less than 0°C (32°F), AND the engine speed is greater than 35 rpm, but less than low idle speed (700 rpm), then ether injection will be activated. Once the engine starts and the low idle speed is attained, the Engine ECM then looks to the ether injection map (contained in the engine software) to determine how long to provide ether injection.
The status of the ether aid solenoid may be viewed through the Advisor Panel (Engine System Status screens) or by using Cat ET.
27
Installed in the top of the secondary fuel filter base are the following fuel system components:
1. fuel temperature sender
2. fuel pressure regulator (check valve) 3. fuel pressure sensor
4. secondary fuel filter bypass switch (differential pressure switch)
The status of the fuel temperature, the fuel pressure, and the state of the secondary fuel filter bypass switch may be viewed through the Advisor panel (Engine System Status screens) or through Cat ET.
1 2 3
28
The fuel transfer pump (1) is located at the front left of the engine, near the bottom of the
engine. The fuel transfer pump is driven by the front gear train. Fuel is drawn from the primary fuel filter and water separator through the upper fuel line (2) by the fuel transfer pump and is returned to the secondary fuel filter through the lower fuel line (3).
The primary (crankshaft) engine speed/timing sensor (4) is located just below the fuel transfer pump. The crankshaft speed/timing sensor provides crankshaft speed and position information to the Engine ECM. This information is also shared with the Power Train ECM as engine speed information. The C15 engine has no engine output speed sensor at the flywheel housing. This is a change from the D8R Series II, which had an engine output speed sensor installed in the flywheel housing which provided engine speed information to the Power Train ECM.
The timing calibration probe adapter (7X1171) is threaded into the timing calibration port (5), after removing the plug. The timing calibration probe, or transducer (6V2197), is then inserted into the adapter. Maintain a 1 mm (.040") air gap between the end of the probe and the
machined surface of the crankshaft counterweight when positioning the probe. The probe will sense a notch that is machined in the crank counter-weight. Cable 7X1695 is used to connect the probe to the timing calibration connector (illustration 31).
1
4
29
The engine pre-lube pump (1) is driven by an electric motor (2). (The pre-lube pump is no longer driven by the starter motor.) If the machine is equipped with pre-lube, the pre-lube pump and motor are installed on the left side of the engine, just above the oil pan. Engine pre-lube is used to ensure that there is sufficient oil pressure throughout the engine oil system before allowing the starter to engage and start the engine. This strategy prevents premature wear of critical engine components. When the key start switch is moved to the START position, the prelube pump may run for a short time before the starter engages.
The Engine ECM determines when to activate the pre-lube pump by monitoring the engine oil pressure sensor. If the oil pressure is less than 30 kPa (4.4 psi) the Engine ECM will activate the pre-lube pump until the oil pressure reaches 30 kPa (4.4 psi), or for up to 45 seconds, whichever occurs first. To override this strategy, turn the key switch to the START position. Then cycle the key start switch to the OFF position and then back to the START position again within one second. This action will allow the starter to engage without cycling the pre-lube pump.
The ecology drain (3) for engine oil is located on the left side of the oil pan. The steel tube (4) to the rear of the pre-lube pump connects to the Quick-Evac connector for engine oil.
NOTE: When the lube cycle is activated, Advisor will inform the operator that
pre-lube is activated and to keep the key start switch in the "START" position until the engine is running.
1 2
3
30
The atmospheric pressure sensor (1) and the engine oil pressure sensor (2) are installed in a block that is located on the lower left side of the engine, between the pre-lube pump and the starter.
The status of these two pressure sensors may be viewed through the Advisor panel (Engine System Status screens) or through Cat ET. Engine oil pressure may also be viewed on the Performance Screen 2 of the Advisor display.
31
The starter (1) is located on the left side of the engine, and is mounted to the front side of the flywheel housing.
Just above the starter is the air cooled A4 Engine ECM (2). The timing probe connector (3) is fastened to the wiring harness coming from the J2/P2 connector (4). The J1/P1 connector (5) is a 70-pin connector and the J2/P2 connector is a 120-pin connector.
The hydraulic hose and fitting (6) supplies lube oil to the flywheel housing. The other end of the hose is connected to a fitting on the side of the torque converter oil inlet port, at the left rear of the torque converter housing. A small amount of power train oil flows through the hose to provide lubrication for the flywheel and pump drive gears. The power train scavenge pump returns the oil from the bottom of the flywheel housing to the power train main sump.
1 2
3
32
Also accessible from the left side of the engine, and located just above the starter, is the cover for inserting the engine turning tool (1). Removing this cover allows the serviceman to insert the 9S9082 engine turning tool to manually turn the engine.
To find Top Dead Center (TDC) of cylinder number one, remove the plug in the TDC port (2), then insert the longer bolt from the cover (1) into the port (2). While applying light pressure to the bolt, turn the engine in the direction of engine rotation until the bolt drops into the hole machined in the front face of the flywheel. A spring-loaded timing pin (136-4632) may also be used to find TDC, instead of the long bolt from the cover.
1 2
The intake air temperature sensor (1) is located on the left side of the engine, just below the primary fuel filter and water separator. The status of this pressure sensor may also be viewed through the Advisor panel (Engine System Status or Performance screen) or through Cat ET. The "Crank-Without-Inject" connector (2) is fastened to the wiring harness just below and in front of the intake manifold. Removing the plug (3) from the "Crank-Without-Inject"
connector (2) and inserting the plug (4) at the left will electronically disable the fuel injectors. This allows the engine to be turned (cranked) using the starter, but without the engine starting. No fuel will be injected into the cylinders in this mode so that the engine cannot start and run. The status of the "Crank-Without-Inject" feature may be viewed through the Advisor panel (Engine System Status screens) or through Cat ET.
33 34 2 3 4 1
35
Located at the left front of the engine, are the following service points:
1. engine oil filter
2. engine oil filler tube
3. engine oil sampling port (S•O•S port)
4. engine oil pressure port
5. engine oil dipstick
NOTE: The engine oil pressure port tests the engine oil pressure after the oil is filtered.
The engine oil sampling port is positioned upstream of the oil filter so an oil sample reflects the cleanliness of the oil before the filter.
1 2
The intake manifold air (boost) pressure sensor (1) is located at the upper left, and at the front of the engine, just ahead of the engine oil filter.
Also located here, and installed in the rear of the timing gear cover, is the secondary (camshaft) engine speed/timing sensor (2).
The status of the intake manifold pressure sensor may be viewed through the Advisor panel (Engine System Status screens) or through Cat ET.
36
37
1
The coolant temperature sensor (1) is installed at the right front corner of the engine, in front of the water pump (2). The status of the coolant temperature sensor may be viewed through the Advisor panel (Engine System Status screens or Performance screen) or through Cat ET. The water pump (2) is located behind and below the alternator, at the right front of the engine. Just above the water pump is the thermostat (coolant temperature regulator) housing (3). Two thermostats are contained in the housing. The shutoff valve for the cab heater return line (4) and the shutoff valve for the cab heater supply line (5) are located to the rear of the thermostat housing. The coolant flow switch (6) is situated outboard from the thermostat housing and installed in the cast tube exiting the water pump.
The status of the coolant flow switch may be viewed through the Advisor panel (Engine System Status screens) or through Cat ET.
38 39 1 2 4 5 6 3
Also accessible at the right front of the engine is the alternator (1) and the air-conditioning compressor (2). Just to the rear of the air-conditioning compressor is the turbocharger (3).
The turbocharger on the C15 ACERT technology engine uses a standard wastegate (4), which is operated by a vacuum line (5). The wastegate acts as a bypass valve for exhaust gasses. When the wastegate opens it allows some of the exhaust gasses to bypass the turbocharger. The wastegate limits boost pressure, which in turn, limits the maximum engine cylinder pressure.
The center section of the turbocharger is water cooled (line not visible) and is lubricated with engine oil, which is supplied through the hard steel tube (6).
40 41 1 2 3 4 5 6
42
The oil-to-water type engine oil cooler (1) is located along the lower right side of the engine. Oil from the oil filter enters the cooler at the oil inlet (2) and passes through tubes surrounded by engine coolant. The cooled oil then exits the cooler at the oil outlet (4) and enters the engine block at port (5).
When the engine is started and the oil is cold, some of the oil bypasses the engine oil cooler through the cooler bypass tube (3).
Coolant enters the engine oil cooler at the front (right, above) of the cooler and exits at the rear, where it then enters the power train oil cooler (6). After flowing around the oil filled tubes in the power train oil cooler, the coolant enters the right side of the engine block through a port (not visible) behind the power train oil cooler.
NOTE: When troubleshooting the cooling system it must be understood that both the
engine oil cooler and the power train oil cooler are heat sources that raise the temperature of the coolant before it enters the engine block.
1
The turbo inlet pressure sensor (1) is installed at the outlet of the air filter canister and is accessible from the right side of the engine.
The turbo inlet air pressure sensor is used to determine air filter restriction. The Engine ECM compares the turbo inlet air pressure to the atmospheric air pressure and calculates a pressure differential between the two pressures. If the pressure differential is too great, it can indicate that the air filter is clogged and needs to be replaced.
Also visible in this illustration is the dust ejector tube (2) that connects the intake air precleaner to the muffler.
The status of the turbo inlet air pressure sensor may be viewed through the Advisor panel (Engine System Status screens) or through Cat ET.
43
1
44
Fuel System
Fuel is drawn from the fuel tank through the primary fuel filter (10-micron) and water separator by a gear-type fuel transfer pump. The fuel transfer pump then directs the fuel through the secondary fuel filter (2-micron).
From the secondary fuel filter,the fuel is then directed to the cylinder head and into the fuel gallery, where it is made available to each of the six MEUI fuel injectors. Any excess fuel not injected leaves the cylinder head. From the cylinder head, the fuel is directed back to the fuel tank through the fuel pressure regulator, which maintains fuel pressure of 558 ± 50 kPa (81 ± 7 psi). The fuel pressure regulator is a check valve that is installed in the secondary fuel filter base.
From the fuel pressure regulator, the excess fuel flow returns to the fuel tank. The ratio of fuel between combustion and fuel returned to tank is approximately 3:1 (i.e. four times the volume required for combustion is supplied to the system for combustion and injector cooling purposes). A differential pressure switch is installed in the secondary fuel filter base and will alert the
operator, via Advisor, of a clogged fuel filter. This Advisor warning indicates that the secondary fuel filter is being bypassed and that the fuel filter should be replaced immediately. The
recommended fuel filter change frequency interval is 500 hours, under optimum conditions. Fuel Tank
Fuel Transfer
Pump Primary
Fuel Filter SecondaryFuel Filter Electric Fuel
Priming Pump
Fuel Pressure Regulator Fuel Gallery
45 Engine Air System
Air is drawn into the engine air pre-cleaner (1) by the vacuum created by the compressor wheel in the turbocharger (3). Exhaust gasses passing through the muffler flow past the dust ejector tube, which is connected to the pre-cleaner by a hose (2). This creates a secondary vacuum in the pre-cleaner housing which draws large contaminant particles from the pre-cleaner through the tube. The large particles are then ejected through the muffler and exhaust stack.
The intake air is then drawn through the air cleaner (4) where the fine contaminants are removed by the filter element. The clean intake air is then drawn into the air inlet of the turbocharger. The turbocharger compresses the air and pushes it out of the compressor outlet. The compressed air then enters the Air To Air AfterCooler (ATAAC) inlet (5). As the intake air passes through the ATAAC core, it is cooled and then exits the ATAAC through the ATAAC outlet (6). The compressed, cooled intake air is then directed to the intake manifold where it enters the cylinder head. The cooler, more dense air results in greater combustion efficiency and fewer emissions. Boost pressure may be read on the status screen in Cat ET. The boost pressure is a calculation of the difference between the atmospheric pressure and the intake manifold air pressure. A failure of the intake manifold air pressure sensor can cause the Engine ECM to perceive a "zero boost" condition, resulting in a reduction in power (derate) by as much as 60%.
1 2 3 4 5 6 7
46
Cooling System
Shown above is a schematic of the cooling system for the D8T Track-type Tractor with the C15 ACERT technology engine. The C15 uses an Air To Air AfterCooler (ATAAC) to cool the intake air. The ATAAC is mounted vertically in the radiator guard (not pictured, in the above illustration). It is in line with, and to the left of the AMOCS radiator cores. The hydraulic oil cooler is an oil-to-air type cooler and is mounted vertically, behind the AMOCS cores.
The AMOCS radiator contains six cores and are the standard "two-pass" design. The hydraulic demand fan is controlled by the Engine ECM. The fan mounted on the front of the radiator guard and is situated in front of the radiator. This arrangement draws air in through the sides of the engine compartment, then through the hydraulic oil cooler, the radiator and the ATAAC, then exits the front of the tractor. This design minimizes the possibility of the fan ejecting debris into the radiator or ATAAC cores (when the fan reversing feature is not activated).
Coolant flows from the water pump, through the engine oil cooler, then through the power train oil cooler, and then into the engine block. Coolant then flows through the engine block and into the cylinder head.
Shunt Tank
Hy
draulic Oil Cooler
C15 Engine Jacket Water Pump Thermostat Housing AMOCS
Radiator Demand FanHydraulic
Power Train
Oil Cooler
Turbo
Engine Oil Cooler Cab
Heater Vent Line
ATAAC (Far Side) Bypass Tube Fill Tube and Cap Hottest Coldest Increasing Coolant Temperature > 92°C < 81°C 87°C
From the cylinder head, the coolant flows to the temperature regulators (thermostats) and either goes directly to the water pump through the bypass tubes or to the radiator, depending on the temperature of the coolant. When the engine is cold, the coolant flows directly to the water pump through the bypass tube. As the temperature of the coolant increases, the thermostats open and the coolant then flows to the radiator. The thermostat housing for the C15 engine contains dual thermostats. The opening temperature for these thermostats is 81° 84°C (178° -183°F). The thermostats should be fully open at 92°C (198°F).
Hot coolant enters the bottom of the radiator and it is cooled the first time as it flows upward through the front side of the AMOCS cores. The coolant is cooled a second time as it flows down the back side of the cores. The coolant then exits the radiator and returns to the water pump.
A small amount of coolant flows to the turbocharger from the thermostat housing, for cooling purposes, and is then directed to the shunt tank. Coolant from the shunt tank is directed to the water pump.
The fill tube and the radiator cap for the cooling system are located on top of the shunt tank. The shunt tank is located directly above the radiator core in the engine compartment. Access to the fill tube is provided by lifting a spring hinged door on top of the radiator guard.
A sight glass in the shunt tank is visible from the left side of the engine compartment. The sight glass should always be filled with coolant. If any air is seen in the sight glass, coolant needs to be added to the system through the cap on the shunt tank.
The air vent lines remove air from the cooling system while the system is being filled and during operation. The shunt tank is a reservoir and retains the expansion volume of the coolant as the coolant temperature increases. The level of the coolant in the shunt tank will rise as the coolant increases in temperature. The coolant level in the shunt tank will fall as the temperature of the coolant decreases.
A drain valve (illustration 48) is present below the radiator and is used to drain coolant from the radiator cores, the engine oil and power train oil coolers, and the cab heater circuit.
Mounted vertically on the back side of the D8T radiator guard is the hydraulic oil cooler (1). In front of the hydraulic oil cooler are the six AMOCS radiator cores (2). At the top of the radiator guard is the shunt tank (3). Mounted vertically on the left side of the radiator guard is the air conditioning condenser (4). In front of the condenser, and to the left of the AMOCS cores is the ATAAC core (5).
Hot coolant enters the radiator at the inlet tube (6). It flows up through the front side of the AMOCS cores, then down the back side, passing twice through the cores. The coolant then exits the radiator through the outlet tube (7) and returns to the water pump.
The radiator drain line from the oil coolers (8) and the drain valve (9) can also be seen here. 47 48 6 7 1 2 4 5 8 9
49
Opening the grill on the front of the radiator guard gains access to the fan (1) (behind the brush guard) and the hydraulic demand fan motor (2) with a self-contained anti-cavitation valve.
If the machine is equipped with a reversing fan, a bi-directional fan motor replaces the standard fan motor with anti-cavitation valve. The fan reversing valve (3) is located at the lower left of the radiator guard.
INSTRUCTOR NOTE: The hydraulic demand fan and the reversing fan strategy will
be discussed later in this presentation.
1
2
50
Hydraulic Demand Fan System
Standard on the D8T Track-type Tractor is the hydraulic demand fan. Although the fan is part of the hydraulic system, it is controlled by the Engine ECM. The Engine ECM considers four inputs for controlling the fan. The hydraulic oil temperature sensor, the engine intake air temperature sensor, and the engine coolant temperature sensor all provide temperature information to the Engine ECM. The Engine ECM monitors all three of these temperature inputs. The highest temperature (relative to the percentage of its temperature map) is the controlling temperature for fan speed. The fan pump discharge pressure sensor is the fourth input to the Engine ECM. Fan pump discharge pressure is controlled by the Engine ECM to determine fan speed.
The Engine ECM monitors the temperature inputs and also considers fan pump discharge pressure to provide a signal to the (proportional) fan pump pressure control solenoid. When the solenoid receives minimum current from the Engine ECM, maximum flow is sent to the fan motor, causing the fan to turn at the maximum controlled rpm (about 1350 + 25 rpm), as shown above. Maximum mechanical pump pressure (high pressure cutoff - no current or a failed solenoid) is set to approximately 15000 + 860 kPa (2175 + 125 psi). Maximum pressure regulated by the Engine ECM software is approximately 13250 + 500 kPa (1922 + 75 psi).
Implement ECM Hydraulic Oil Temperature Sensor Intake Air Temperature Sensor Engine ECM Temperature Sensor Fan Motor Hydraulic Oil Cooler Cooler Bypass Valve Demand Fan Pump Pump Pressure Sensor HFPD
To Case Drain Manifold
From Suction Manifold To Suction Manifold
Pilot Drain from Dual Tilt Valve Drive from Steering Pump Pump Control Valve Fan Pump Pressure Control Solenoid
Cat ET may be used to reset the maximum controlled fan system pressure from the maximum pressure set at the factory. This adjustment may be necessary to correct the maximum
controlled fan speed due to differences in altitude between the factory and the tractor's work site. In cooler weather, the Engine ECM may utilize an engine software strategy called "Cool Engine Elevated Idle Strategy" when the following conditions are met:
- Coolant Temperature < 70°C (158°F) - Parking brake is set to ON
- Transmission in NEUTRAL - Throttle switch set to LOW IDLE
Under these conditions, the Engine ECM will automatically increase engine speed, up to 1100 rpm, in an effort to increase coolant temperature. When any of the four conditions are not met, the strategy is ignored.