Usage:
ESS System Overview
The Caterpillar Engine Supervisory System (ESS) is designed to provide total control over the operation of the G3600 engine. This includes start/stop control, engine monitoring and protection, governing and air to fuel ratio control, and an integrated self-diagnostic system. The Engine Supervisory System consists of a control panel (ESS Panel), engine junction box, switches, potentiometers, sensors, actuators, solenoids and associated wiring.
Controls and Functions
The ESS System consists of three interactive systems: Start/Stop/Prelube System, Engine Monitoring and Protection System, Engine Control, System.
Start/Stop/Prelube System
The Start/Stop/Prelube System controls the prelube pump operation, engine starting system and engine stopping system.
The Mode Control Switch (MCS) has four positions- Off/Reset, Auto, Start and Stop.
In the Automaticposition (12 o'clock), the engine will start automatically whenever the initiate contact is closed and prelube is complete. The engine will shut down after the initiate contact opens. An adjustable cooldown time can be programmed to give a 0 to 30 minute cooldown period before the engine shuts down. Cat recommends 0 minute cooldown on G3600's.
In the Startposition (3 o'clock), the engine will prelube, start and run as long as the MCS is in this position and a shutdown does not occur.
In the Stopposition (6 o'clock), the fuel solenoid shuts the engine down immediately, unless a cool-down cycle is programmed into the Status Control Module (SCM). If a cool-down time is programmed into the SCM, the engine will immediately shutdown after the programmed time has elapsed. This position also supplies power to the ESS system without starting the engine.
In the Off/Resetposition (9 o'clock), the engine begins shutdown sequence and the diagnostic lamps are reset. The power will be removed from the ESS when the postlube cycle is complete.
An emergency Stop Push Button (ESPB) is located on the front of the ESS panel. When this button is depressed, the fuel is shut OFF, the engine ignition is turned OFF, and there is no postlube.
| NOTICE |
|---|
The Emergency Stop Button (ESPB) should not be used for normal engine shutdowns. To avoid possible engine damage use the Mode Control Switch (MCS) for normal engine shutdown operation. |
To restart the engine
- * Clear the condition that required the emergency stop push button to be used
- * Turn MCS to "OFF/RESET"
- * Reset ESPB
- * Turn MCS to Either "Start" or "Auto"
- * Turn MCS to "OFF/RESET"
Engine Monitoring and Protection System
The Engine Monitoring and Protection system provides engine protection for vital parameters, displays engine parameters, generates alarms (audible and/or visual) when one or more parameters are outside acceptable limits. This system has the ability to cause an engine shutdown or inhibit starting if certain parameters are outside acceptable limits.
Engine Control System
The Engine Control system provides engine governing, air-to-fuel ratio control, and power limiting.
Engine Supervisory System (ESS) Panel
Figure 1.1-ESS Panel
(1) Tachometer Display(2) Computerized Monitoring System.(3) CMS Gage Module.(4) Fault Indicators.(5) LED Indicators for the Timing Control Module.(6) Timing Control Module.(7) Display for the Engine Control Module.(8) DISPLAY SELECT Switch.(9) Engine Control Module.(10) GAGE GROUP SELECT Switch.(11) Fuel Energy Content Potentiometer.(12) Speed Control Potentiometer.(13) Mode Control Switch.(14) Dimmer Switch.(15) GAGE DATA SELECT Switch(16) Digital Diagnostic Tool (DDT) Connection.(17) Manual Prelube Switch.(18) EMERGENCY STOP Button.(19) Status Control Module.(20) Exhaust Pyrometer.
ESS Panel
The ESS Panel houses the control modules and associated switches and potentiometers required to provide the functions described previously.
The panel contains the following modules:
- * Engine Control Module (ECM)
- * Timing Control Module (TCM)
- * Computerized Monitoring System (CMS)
- * Status Control Module (SCM)
- * Exhaust Pyrometers
- * Timing Control Module (TCM)
The panel also contains the following switches and Potentiometers:
- * Gage Group Select Switch
- * Gage Data Select Switch
- * Dimmer Switch
- * Display Select Switch
- * Mode Control Switch (MCS)
- * Manual Prelube Button
- * Emergency Stop Push-button (ESPB)
- * Desired Engine Speed Potentiometer
- * Fuel (Quality) Energy Content Potentiometer
- * Gage Data Select Switch
The following is a brief description of the function of each of the control nodes.
Engine Control Module (ECM)
Figure 1.2-Engine Control Module
The primary function of the ECM is to govern engine speed and to control the air-to-fuel ratio. The ECM also performs the role of system coordinator. Nearly all of the functions of the ESS are routed through the ECM. The ECM Personality Module contains many of the protection system set points and it controls most of the ESS operations.
The ECM provides status and diagnostic information through light emitting diodes (LED's) and an alphanumeric display. The ECM indicates the type of information displayed on the alphanumeric panel by lighting one of the eight LED's located next to the display. If an LED is ON continuously, it indicates the type of information being displayed. If an LED is flashing, it indicates there is information of that type available, but not presently displayed.
For example, if the ECM is indicating a continuously green Status Mode, but the red Sensor Fault LED is flashing, it indicates there is a sensor related fault present, but not currently displayed. The display select switch needs to be toggled to show the diagnostic code.
Control of the ECM displayed information is provided by the display select switch on the front of the ESS panel. When the switch is toggled, it causes the display to move to the next parameter. The order of display is shown below.
- * Desired Engine Speed (DRPM)
- * Fuel Energy Content (BTU)
- * Diagnostic Codes in Order of Occurrence
- * Fuel Energy Content (BTU)
Electronic System Overview
The alphanumeric display will normally indicate either Desired Engine Speed or Fuel Energy Content, depending on the last parameter selected. If diagnostic codes are present, the display will indicate the presence of these conditions by illuminating the appropriate LED next to the alphanumeric display, and turning ON the appropriate F1 through F12 lamp on the CMS. Toggling the Display Select switch will cause the display to indicate other diagnostics in order of occurrence. After a diagnostic code is displayed, it will be cleared upon toggling of the display select switch, unless the diagnostic code is still active.
Other Display Indications
If the ECM shuts down the engine as a result of a detected diagnostic, the condition which caused the shutdownwill be indicated by a FLASHINGdiagnostic code. Diagnostic codes which do not cause engine shutdowns (Alarm codes) will be indicated by a solid ON (not flashing) diagnostic code.
A "RST REQD"diagnostic will also be present on the ECM to indicate the system must be reset before restarting. Turn the Mode Control Switch to the OFF/RESETposition to clear the diagnostic code and reset the system to allow the engine to be restarted.
SHUT DN-Normal Engine Shutdown
This display indicates the engine has completed a normal shutdown sequence initiated by an external input or the Mode Control Switch is in the STOPposition. The SCM performs the shutdown sequence when an external shutdown signal is received and passes a signal from the Run Relay to the ECM. The ECM will display "SHUT DN" when the signal from the SCM is received.
The ECM does not require a reset before the engine may be restarted after a normal shutdown. This code will automatically clear when the engine is started.
If the shutdown input (from the SCM) is still requesting shutdown after diagnostic acknowledge, the yellow caution LED will flash and the shutdown indication will appear during a scroll or the alphanumeric displays until the shutdown input is removed.
PC CAL-Prechamber Calibration Mode
This code indicates that the system is in the prechamber needle valve calibration mode or Magneto Calibration Mode.
Timing Control Module (TCM)
Figure 1.3-Timing Control Module
The Caterpillar Detonation sensitive Timing Control Module (TCM) provides detonation protection for the engine and electronic adjustment of ignition timing. This ignition system consists of the TCM and the Magneto/MIB, or the CIS. The TCM determines ignition timing and communicates ignition timing with the Ignition System. It also displays, and provides to the ECM, other system diagnostics.
Engine timing, controlled by the TCM, is based on the desired timing, determined by the ECM personality module. Timing automatically adjusts according to the engine operating conditions. Engine speed, load and detonation are used to determine desired timing. Ignition timing is controlled by three signals sent from the TCM to the Ignition System. The Ignition System sends a signal to the TCM indicating spark plug firing. The TCM uses this signal to calculate actual engine timing.
The TCM uses sensors to monitor timing components for problems. If a component or harness failure occurs, the TCM will sense the problem, illuminate an LED and annunciate a diagnostic code.
Caterpillar Magneto Ignition Systems
Magneto Systems
The Magneto Interface Box (MIB) receives three signals from the TCM which define the desired engine timing. The MIB then closes the connection between pin-A and pin-B or pin-E and pin-F ( on the magneto) at the time the magneto is to fire the spark plug. The magneto capacitor discharges are monitored by the MIB. The MIB converts the capacitor discharges into a low voltage equivalent signal and sends the signal to the TCM. When operating in Magneto Calibration Mode (MAG CAL) the connections between pin-A and pin-B and pin-E and pin-F are continuously connected.
Variable Timing Magneto
Fixed timing magnetos discharge the ignition capacitor to the ignition transformer as soon as the rotor enters the magnetic field of a stationary pole. For the variable timing magnetos, the ignition capacitor will discharge at any position while the rotor is within the timing window and an external switch (in the MIB) is closed. To retard timing, the external switch is closed further into the timing window. To operate the variable timing magneto like a fixed timing magneto, the external switches are held closed. This is accomplished by placing the magneto in manual override using the DDT in the MAG CAL Mode.
Engine Sensors
The Timing Control Module uses two sensor signals for the ignition timing control and a Detonation Sensor for detonation protection. The Crank Angle Sensor (CAS) and the Timing Control Magnetic Pickup (TCMPU) provides cylinder #1 Top Center location and rotation position needed to control timing. Detonation Sensors produce an electrical signal from the mechanical engine vibrations used to calculate detonation levels.
The Crank Angle Sensor(CAS) is a passive magnetic pickup sensor used to indicate crankshaft angle to the TCM. It indicates the Top Center (TC) of Cylinder #1, and is used to control timing to calculate actual timing, and to calculate engine speed. The signal is generated when the TC hole in the flywheel passes by the pickup.
The Timing Control Magnetic Pickup(TCMPU) is a passive magnetic pickup sensor used to indicate engine speed to the TCM and provide fine resolution for crankshaft angle. It produces a signal whenever a ring gear tooth on the flywheel passes by. The signal is used to calculate engine speed, monitor crankshaft angle between TC pulses and create the clock signal to the Magneto Interface Box or the Caterpillar Ignition System electronics.
Detonation Sensorsare used to monitor the engine for excessive detonation. The output is a filtered and amplified electrical signal representing engine mechanical vibrations. Vibration signals are processed by the TCM to determine the engine detonation level and adjust ignition timing to control detonation while maintaining the best operational performance.
Interaction of the Engine Timing Control Module (TCM) and Ignition System
The TCM provides three signals to the Magneto Interface Box (MIB), or the CIS, depending on the type of ignition system installed on the engine, to communicate the desired ignition timing. These signals are the Ignition Interface Clock, the Reset Pulse signal, and the Manual Override signal. The MIB, or CIS, returns the Magneto Interface Ignition Pulses signal (Ignition Pulses) to the TCM. The TCM calculates Actual Engine Timing and performs some ignition diagnostics from this signal.
Ignition Interface Clock Signal
The Ignition Interface Clock signal is a square wave version of the TCMPU sensor signal. This signal provides a timing clock for the MIB or CIS controls.
Reset Pulse Signal
The Reset Pulse indicates to the MIB, or CIS, the desired ignition timing requested by the TCM. The pulse is sent once for every complete fire cycle of the engine (two crankshaft revolutions), beginning with the firing of Cylinder #1.
NOTE: Refer to Timing System Signal Interaction Diagram on page 1-9 of this manual.
Ignition Interface Pulses
The Ignition Interface Pulse signal is derived from the odd bank firing. Its waveform indicates the firing of the odd bank capacitor and the firing of the odd cylinders. One pulse is shown for each odd bank cylinder. This signal is used by the TCM to calculate ignition timing and some ignition diagnostics.
Manual Override Signal
The Manual Override signal tells the MIB, to control the timing in electronic timing mode or manual mode.
Interaction of the Timing Interface Signals
When the manual override is held below 1 volt, the ignition system is in variable timing mode. When the override signal is above 1 volt the ignition system is in the MAG CAL (fixed timing) mode.
The Timing Control Module (TCM) generates a clock signal by squaring the Timing Control Magnetic Pickup (TCMPU) signal. This clock signal is used by the ignition system to track crankshaft position relative to top dead center (TDC).
When the ignition system receives the reset pulse from the TCM, it counts nine (9) clock signal edges and then fires cylinder number one. The ignition system continues to count clock signal edges and fire the remaining cylinders in proper sequence.
Ignition timing is calculated by, comparing the offset between the crank angle sensor (CAS) signal, and cylinder number one ignition interface pulse. Ignition timing is calculated by the same method when the ignition system is in fixed timing mode (Mag Cal mode).
Diagnostic Overview
The Timing Control Module provides diagnostics to the ECM to assist the customer in troubleshooting system faults. The Timing Control Module has a display window with ten LED's to indicate system faults or status conditions.
When the TCM detects a fault, one of the red LED's will be turned ON and a diagnostic code is generated on the ECM display and can be retrieved by toggling the Display Select switch. The diagnostic is logged (saved) in memory until the Timing Control Module is powered down or the diagnostic code is acknowledged with the Display Select switch.
NOTE: The diagnostics are reset through the Display Select switch.
Caterpillar Ignition System
The Caterpillar Ignition System (CIS) has been designed in conjunction with the Timing Control Module (TCM) for use on natural gas fueled engine. This system is designed to replace both the magneto and the magneto Interface Box. An additional sensor is also added to determine camshaft position. New features include advanced spark control, primary diagnostics, spark diagnostics, self-diagnostics, pickup diagnostic and serial communication. The system consists of two main parts: and engine mounted Ignition Module and an optional user interface display module.
Caterpillar Ignition System control to Engine timing control switch
A 16 position rotary switch located inside the CIS box, is used to match the CIS timing reference to the Hall Effect sensor located on the camshaft of the engine. The timing is calibrated the first time the engine is started at the factory; therefore, no changes are needed, unless ignition system components are replaced.
To set the timing, the engine must be started with the DDT in MAG CAL mode, (DDT screen 40), and the engine RPM must be at or above 550 rpm. While observing the displayed timing on the DDT, move the 16 position switch one position at a time, until the displayed timing is as close to 28 degrees as possible. The final MAG CAL timing calibration value should be about 27.8 to 28.4 degrees.
After the timing switch is set, move from DDT screen 40 (out of Mag Cal), to DDT screen 11 to view the running engine timing. If the timing is stable and matches the desired timing on the DDT, closed and properly tighten the cover on the CIS Module.
LED Indicators
Five LED's in the CIS module indicate CIS status. Four are red and the fifth LED is green.
Power LED
When the unit is powered this red LED is illuminated.
TX LED
When the unit is transmitting data on the RS-485 serial link this red LED will flash, if the Display Module is connected and working properly.
RX LED
When the unit is receiving data on the RS-485 serial link this red LED will flash, if the Display Module is connected and working properly.
Alarm LED
This red LED is illuminated to indicate an alarm or fault has occurred.
H.E. P/U LED
When the Hall Effect Pickup is near the magnet this green LED is illuminated.
Interface Connector
One RS-485 serial port is provided at the bottom of the CIS Module, it is the spin connector at the far left. This port is most often used to communicate.
Display Module
The Display Module serves as the customer interface module for the CIS system. An RS-485 serial communications port is used to connect the Display Module to the Ignition Module.
NOTE: For further information concerning the CIS module refer to the Systems Operation Testing and Adjusting manual for your engine.
Timing System Signal Interaction Diagram
Computerized Monitoring System Module
Figure 1.8-CMS Display Panel
The primary function of the CMS is to display important engine operating data. The CMS also reads sensor information and communicates the information to the ECM.
Engine parameters are provided as solidly illuminated digital gages and a digital readout. The film below the display indicates (appropriate ISO symbols) the information displayed by each of the six small gages.
The single large gage always indicates engine speed. The digital readout immediately below the large gage indicates which gage is displayed by the number in the upper portion and the data value in the lower portion.
NOTE: The units of the displayed value are indicated in the film area.
CMS Gage Module (Group 1)
To view these gages the Group Selectswitch must be in the
Gage 1 (Inlet Manifold Air Temperature)
This display indicates the inlet manifold air temperature °C (°F). To display the temperature on the digital readout, toggle the Gage Data Selectswitch until the upper readout indicates 1.
Gage 2 (Coolant Temperature)
This display indicates the engine coolant temperature in °C (°F). To display the temperature on the digital readout, toggle the Gage Data Selectswitch until the upper readout indicates 2.
Gage 3 (Fuel Correction Factor)
This display indicates the correction factor that the air-to-fuel ratio control system is applying. Indications to the left of center (or digital value less than 100) means the control system is observing that the fuel has combustion characteristics of a fuel of lower energy content than is indicated by the Fuel Energy Content Input.
Indications to the right of the center (or digital value greater than 100) means that the control system is observing that the fuel has combustion characteristics of a fuel of higher energy content than is indicated by the Fuel Energy Content input to the control system.
To display the correction factor on the digital readout, toggle the Data Selectswitch until the upper readout indicates 3.
NOTE: If the red rings are ON, the engine is in feedback operation. If the red rings are OFF, the engine is in PC-CAL operation.
Gage 4 (Inlet Manifold Air Pressure)
This display indicates the absolute inlet manifold air pressure in kPa (psi). To display the pressure on the digital readout, toggle the Gage Data Selectswitch until the upper readout indicates 4.
Gage 5 (Engine Oil Pressure)
This display indicates the engine oil pressure in kPa (psi). In addition the green bar above this gage is used to indicate if prelube level is present (when the Mode Control Switch is in the AUTO or START positions). To display the pressure on the digital readout, toggle the Gage Data Selectswitch until the upper readout indicates 5.
Gage 6 (Engine Load)
This display indicates the percentage of available engine torque as indicated by fuel flow. To display the engine load on the digital readout, toggle the Gage Data Selectswitch until the upper readout indicates 6.
CMS Gage Module (Group 2)
To view these gages the Group Selectswitch must be in the right position..
Gage 7 (Oil Filter Differential Pressure)
This display indicates the differential pressure across the oil filter in kPa (psi). To display this pressure on the digital readout, toggle the Gage Data Selectswitch until the upper readout indicates 7.
Gage 8- Air Restriction (Left or Inline)
This display indicates the pressure drop in kPa/10 (inches of H2O/10) between atmospheric pressure and the inlet to the left or inline turbocharger. To display the pressure on the digital readout, toggle the Gate Data Selectswitch until the upper readout indicates 8.
Gage 9 (Crankcase Pressure)
This display indicated the crankcase pressure in kPa/10 (inches of H2/10). To display the pressure on the digital readout, toggle the Gage Data Selectswitch until the upper readout indicates 9.
Not Used (Pressure) This display (10) is normally blank.
Some applications have the gage display Coolant Outlet Pressure in kPa (psi). To display this pressure on the digital readout, toggle the Gage Data Selectswitch until the upper readout indicates 10.
Gage 11 (Air Restriction Right) (Vee Only)
This display indicates the pressure drop in kPa/10 (inches of H2/10) between atmospheric pressure and the inlet to the right turbocharger. To display the pressure on the digital readout, toggle the Gage Data Selectswitch until the upper readout indicates 11. On inline engines this display will be blank.
Gage 12 (Starting Air Pressure)
This display indicates the air pressure in kPa (psi) available to the air starting system. To display the pressure on the digital readout, toggle the Gage Data Selectswitch until the upper readout indicates 12.
Statue Control Module (SCM)
Figure 1.9 - Status Control Module
The SCM provides basic engine protection as well as Start/Stop Control. The Status Control Module displays Status, Diagnostic and Shutdown information on an LCD display and six LED indicators.
Status Indication
The status indicators are designed to provide status information and to assist in troubleshooting engine problems. Status information is provided as a digital display with the appropriate ISO symbol.
Hour Meter
This display indicates engine service hours. This display is indicated when the pointer at the bottom of the LCD display points to the ISO symbol for service hours.
Engine Speed (RPM)
This display is indicated when the pointer at the bottom of the LCD display to the ISO symbol for the engine speed.
System Battery Voltage
This display is indicated when the pointer at the bottom of the LCD display points to the ISO symbol for system voltage.
Engine Oil Pressure
This display indicates lube oil pressure in kPa or (psi). This display is indicated when the pointer at the bottom of the LCD display points to the ISO symbol for engine oil pressure.
Engine Oil Temperature
This display indicates engine oil temperature in degrees °C or (°F). This display is indicated when the pointer at the bottom of the LCD display points to the ISO symbol for oil temperature.
SCM Display Select Switch
The display scrolls from one parameter to the next automatically. To latch the display from scrolling to the next parameter, press the display select switch on the SCM once. To start scrolling, press the switch again.
Diagnostic (Fault) Indications
A diagnostic indication means that the system has detected the failure of components associated with the module. Diagnostic (fault) indications are displayed on the same display as the status information. When a diagnostic code is displayed, the arrow that indicates which of the parameters are displayed will be missing and a flashing DIAG will be displayed. If several diagnostic's are present, the diagnostic codes will be displayed in sequence.
Shutdown Indication
A shutdown indication means the module has shut the engine down due to a detected problem. Shutdown information is provided by six LED indicator lamps.
- * Over Crank
- * Over Speed
- * High Oil Temperature
- * Low Oil Pressure
- * Emergency Stop
- * Auxiliary Shutdown
- * Over Speed
Pyrometers
Figure 1.10 - Pyrometer
The digital Pyrometer, with alarm, is an electronic instrument designed to monitor temperature using industry standard thermocouple probes.
This device allows the readout of up to nine engine exhaust temperature locations. Two digital Pyrometers are used on engines with more than eight cylinders.
A front panel push button switch allows the selection of the desired exhaust port thermocouple. The location selected and the monitored temperature are displayed continuously on the LCD display.
Channel "0" is used to measure exhaust stack temperature. The channel "0" thermocouple input is continuously compared against a high limit setpoint while providing readout and monitoring of high limit protection for the exhaust stack on channel "0"
The high limit setpoint input is set by the operator from the front of the instrument. If the setpoint is exceeded, the pyrometer will close an output switch to ground indicating to the ECM to shutdown the engine.
Illustration 1. 179-9001 Pyrometer (meter)
The 179-9001 Pyrometer (Main) is an electronic scanner for exhaust temperatures. The scanner can motor 24 points via standard type K thermocouples. An LCD displays the number of the channel and the temperature in °C or °F. The scanner has two switches that can be wired to alarms or relays. The scanner can provide readings, monitoring, and alarms for the temperatures of 20 cylinder exhaust ports and four turbocharger inlets and/or outlets.
The scanner has a microprocessor for processing the input signals. The microprocessor has non-volatile memory for storing programmable parameters and other data. The user interface is a keypad. The following functions are among the uses of the keypad:
- * Change the display of the temperatures to °C to °F
- * Select automatic display or manual display for the scan.
- * Display a history of channels which have exceeded the setpoints.
- * Change the filter for the display in order to stabilize the readings for a signal that is fluctuating.
- * Program the temperature setpoints.
- * Lock the keypad in order to help prevent changing of the non-volatile memory.
- * Calibrate the scanner.
- * Select automatic display or manual display for the scan.
The scanner can monitor temperatures from 0 to 850 °C (32 to 1562 °F). Six temperature setpoints for the alarms can be programmed with the keypad. If an alarm occurs, the scanner has two output switches that can provide a signal to an indicator, a switch, or a relay.
The range for the input voltage is 10 to 32 VDC. A power supply of 12 or 24 VDC can be used.
If you have the 179-9001 Pyrometer, refer to RENR4911 for programming and service.
Detonation Mixing Control System Overview
The Caterpillar Detonation Mixing Control (DMC) is designed to expand the detonation protection capabilities of engines equipped with the Timing Control Module (TCM). The early protection system monitor detonation levels using up to two detonation sensors (one per bank). The Detonation Mixing Control will expand this protection, allowing the protection systems to monitor the detonation levels using up to eight detonation sensor (for a 16 cylinder engine or one for every two cylinders).
Control Module Operation
The DMC Module controls which detonation sensor signal is passed to the Timing Control Module and provides operation diagnostics.
The DMC operation is similar to having two 1-4 selection switch devices (one for left bank and one for the right bank) to control which detonation sensor signal is passed to the Timing Control Module (TCM). The DMC uses each of these switches to continuously pass one of the input detonation sensor signals to the DMC detonation signal output in the proper firing order for the engine cylinders. The DMC does not process or analyze the detonation sensor signals.
The Timing Control Module receives two detonation sensor signals which it processes to determine the detonation level of the engine. With the Detonation Mixing Control, the two detonation signals processed by the Timing Control are composed of pieces of the detonation signals from all of the Detonation Sensors.
The pieces of the detonation sensor signal passed to the Timing Control Module are determined by the firing order. The DMC System will pass the detonation signal from the Detonation Sensor closest to an igniting cylinder. The DMC begins passing a detonation sensor signal to the TCM just before the ignition of the cylinder. The DMC continues to pass this, signal until just before the next cylinder is about to be ignited.
The number of Detonation Sensors and their location on the engine is based upon the engine type. The system is designed with one Detonation Sensor for every two cylinders. Each Detonation Sensor measures the structural vibrations for the two closest cylinders. The engine configuration, engine family and number of cylinders, is passed over the CAT Data Link from the ECM.
If a component failure occurs, the control will sense the problem and notify the operator by creating a diagnostic code.
Engine Sensor and Signals
The DMC uses information from the TCM Magnetic Speed Pickup and the Cylinder #1 Combustion Buffer to control which detonation sensor signals will be passed to the Timing Control Module (TCM).
The Speed Sensorsignal provides incremental crankshaft rotational movement for the control module. The gear teeth around the flywheel provide the signal pattern detected by the sensor. The control determines engine speed and crankshaft rotation position from this sensor signal. This sensor signal is shared with the timing DMC speed sensor input and the status control speed sensor input.
The Cylinder #1 Combustion Bufferprovides a reference point in the firing order to the control module. The cylinder #1 combustion buffer signal indicates when cylinder #1 ignition occurs. This information is processed by the DMC module to determine cycle rotation, the switching timing and diagnostics.
The Detonation Sensorsmonitor the engine for detonation. One sensor is mounted between each pair of cylinders on each engine bank and monitors the engine vibrations for those two cylinders. The vibration data is passed through the DMC control module and is processed by the Timing Control module (TCM) to determine detonation levels.
DMC Diagnostics Overview
The DMC control has the ability to diagnose existing system problems. When a problem is detected, the DMC sends a code to the ECM where it is displayed.
The diagnostics for the Detonation Sensors and signals are performed by the Timing Control Module (TCM) and DMC. Should the system lose a sensor or signal, the TCM will diagnose the condition and take the appropriate action. If there is a sensor or harness problem that leads to an abnormal voltage on a detonation sensor signal wire, the DMC will diagnose it, and send a code to the ECM.
The DMC diagnostics are also performed on the input control signals, flywheel teeth signal, and cylinder #1 ignition signal. The diagnostic code may indicate a warning or shutdown condition.
Diagnostic Codes
Diagnostic Codes are used by the DMC System to alert the operator of a system problem and indicate its nature. The diagnostic codes may indicate a warning or shutdown condition.
If a problem is indicated by a diagnostic code, it should be investigated and corrected as soon as possible.
Diagnostic conditions on the DMC are sent to the ECM where they are displayed.
Detonation Sensor Diagnostics
The No Detonation Sensor Diagnostics (318-12 and 319-12) are reported by ESS System.
Sensor and Connector Locations
Figure 1.11 - Front View
Sensor and Connector Locations
Figure 1.12 - Rear View In Line
Sensor and Connector Locations
Figure 1.13 - Left Side View In-Line
Sensor and Connector Locations
Figure 1.14 - Right Side View In-Line
Service Tools
The Caterpillar Electronic Service Tools for the G3600 Engine Supervisory System are designed to help the service technician analyze and locate faults or problems within the system. It is required to perform some sensor calibrations electronic adjustments and to read or change system/engine parameters.
The Communication Tools consist of the DDT, and the DDT Harness and the Adapter Harness. These three components are required for the operator or technician to communicate with the ESS to retrieve engine operation status data and program engine parameters.
The Digital Diagnostic Tool(DDT) communicates with the G3600 ECM to read various engine parameters such as engine rpm, inlet manifold pressure, etc, and to program the ECM. The DDT has two adapter cables that are used in order to access the ECM.
Service Tools Table
Measurement Service Tools
The measurement service tool for the G3600 Engine Supervisory System is a Digital Multimeter. This device is all that is required and is used extensively throughout the troubleshooting procedures to analyze the system operation. A 152-7213 Scopemeter, a 9U7330 Digital Multimeter and the associated probes are suitable for making all necessary measurements.
Figure 1.16 - Service Tools
Interpreting PWM Signals
A Pulse Width Modulated Signal (PWM) is a signal consisting of variable width pulses at fixed intervals, whose TIME ON verses TIME OFF can be varied (Also referred to as DUTY CYCLE). PWM Command signals to the Actuators (Choke, Wastegate or Fuel) must have a complete circuit through the Actuator and back to signal ground. An OL on the Electronic Service Tool (Fluke Meter) PWM Display screen indicates an open circuit.
Pulse Width Modulation Signals