Some parameters are protected by security passwords. Customer passwords or factory passwords may be required in order to change these parameters. Refer to Troubleshooting, "Customer Passwords" and Troubleshooting, "Factory Passwords" for details.
Note: Factory passwords are only available to service technicians from an authorized Caterpillar Dealership. Customers of Caterpillar do not have access to the Caterpillar Factory Password System (FPS). If the parameters that are protected with factory passwords are changed without authorization from Caterpillar, the repair may not be covered under the Caterpillar warranty.
Refer to Systems Operation/Testing and Adjusting, "Electronic Control System Parameters" for additional information.
Table 1 is a list of the parameters that can be configured for G3520B Engines. The parameters are programmed into the ECM via the Cat ET. The values of the parameters can be viewed on the "Configuration" screen of Cat ET.
ECM Identification Parameters
Equipment ID
The customer can assign an "Equipment ID" for identification for the engine application.
Engine Serial Number
The engine serial number is programmed into the ECM at the factory. The number is stamped on the engine information plate.
Timing Control
These timing parameters allow the customer to program ignition timing electronically in order to meet the needs for specific applications and installations.
Note: The actual ignition timing at a given instance may vary from the desired timing value. This variance is due to variations in the engine speed, engine load, or detonation.
First Desired Timing
The "First Desired Timing" is determined with the methane number of the primary fuel that is used. Use the Engine Performance Sheet, "Fuel Usage Guide". The ECM selects the "First Desired Timing" when the timing select switch creates an open circuit for terminal J1-20 at the master ECM.
Note: The desired timing should be determined by using the Caterpillar Software, LEKQ6378, "Methane Number Program" with the results that are from the fuel analysis. Use of only the data from the gas analysis can result in incorrect settings.
Second Desired Timing
The "Second Desired Timing" is determined with the methane number of the alternate fuel that is used and the Engine Performance Sheet, "Fuel Usage Guide". The ECM selects the "Second Desired Timing" when the timing select switch creates a short circuit to ground for terminal J1-20 at the master ECM.
If an alternate fuel is not used, enter the same timing value for the "Second Desired Timing" parameter that is entered in the "First Desired Timing" parameter.
Desired Engine Timing Offset
This feature provides the offset of engine ignition timing to compensate for timing errors due to resistances in electrical circuitry and stackup of mechanical tolerances.
This parameter provides a manual method that will allow additional timing adjustment to be performed after calibration of the speed/timing sensor. Perform a negative adjustment to this parameter for retardation of engine timing. Perform a positive adjustment to this parameter in order to advance the engine timing. Only perform an adjustment to this parameter if engine operating indicators and measured data indicate that an adjustment is required.
Air/Fuel Ratio Control
Before the initial start-up, a current gas analysis is required. Periodic gas analyses are also recommended. Use the Caterpillar Software, LEKQ6378, "Methane Number Program" in order to calculate the parameters for air/fuel ratio control for Caterpillar Gas Engines. The results are programmed into the ECM.
Note: Use the Caterpillar Software, LEKQ6378, "Methane Number Program". The improper programming of the air/fuel ratio control can result in damage to the engine.
The Caterpillar Software, LEKQ6378, "Methane Number Program" is also contained in Caterpillar Software, LERW4485, "GAS ENGINE RATING PRO - VERSION 3.01". This software also contains information that is related to engine performance.
Fuel Quality
This parameter is the fuel Low Heat Value (LHV). The air/fuel ratio control of the ECM will compensate for some inaccuracy in this setting. The ECM derives a corrected value that is multiplied by the "Fuel Correction Factor". The status of the parameter can be viewed with Cat ET.
The "Fuel Quality" parameter can be used to change the air/fuel ratio when the engine is operating in the open loop mode. To richen the air/fuel mixture, reduce the value. The calculation will compensate for the reduced LHV by increasing the fuel flow. To lean the air/fuel mixture, increase the value. The calculation will compensate for the increased LHV by reducing the fuel flow.
Gas Specific Gravity
This parameter is the fuel-specific gravity in relation to the specific gravity of air. The ECM does not use this information. The ECM provides the information to the fuel metering valve via the CAN data link. Some fuel metering valves require an input for the "Gas Specific Gravity" in order to precisely meter the fuel flow.
Fuel Specific Heat Ratio
This parameter is a ratio of the fuel-specific heat at a constant pressure and at a constant volume. The ratio is also known as "k". The ratio is related to the expansion of the gas across the fuel metering valve. The ECM does not use this information. The ECM provides the information to the fuel metering valve via the CAN data link. Some fuel metering valves require an input for the "Fuel Specific Heat Ratio" in order to precisely meter the fuel flow.
Emissions Feedback Mode configuration
The "Emissions Feedback Mode configuration" can be set to "NOx Feedback" or to "Feedback Disabled". This feature allows the feedback mode to be disabled in order to troubleshoot the engine. The disabling of this feature can help determine whether the air/fuel ratio control is the cause of instability of the engine.
If the signal from the NOX sensor is not available, the control system does not have information necessary for maintaining the desired exhaust emissions.
If there is a problem with the NOX sensor, this parameter can be set to "Feedback Disabled". "Feedback Disabled" allows the engine to run in the open loop mode until a new sensor is obtained. During operation in this mode, an emissions analyzer must be used to verify the emissions level. The "Fuel Quality" parameter is adjusted in order to change the air/fuel mixture for the engine.
When the "Emissions Feedback Mode configuration" is set to "NOx Feedback", adjustment of the "Fuel Quality" parameter does not affect the air/fuel ratio. Do not adjust the "Fuel Quality" parameter when the "Emissions Feedback Mode configuration" is set to "NOx Feedback".
Note: Do not operate an engine that is unattended in the open loop mode if the fuel has an LHV that is changing. The engine risks a shutdown due to lean misfire or to detonation.
Desired Engine Exhaust NOx Level Setting
The ECM contains a control map for the NOX emissions that is programmed at the factory. The "Desired Engine Exhaust NOx Level Setting" parameter is used to trim this control map when the engine is in "NOx Feedback" mode. If the measured NOX emissions are not the required value, decrease the "Desired Engine Exhaust NOx Level Setting". The parameter decrease is to lean the fuel mixture. Increase the "Desired Engine Exhaust NOx Level Setting" parameter in order to richen the fuel mixture. The engine must run at normal operating temperature. The engine speed set to a minimum of high idle. The engine load set to a minimum of 50 percent.
Air/Fuel Proportional Gain
The "Air/Fuel Proportional Gain" determines the speed of the fuel metering valve response. The gain is for when you make adjustments for the difference between the actual air/fuel ratio and desired air/fuel ratio.
The factory default setting is zero. This value should not require adjustment. If problems occur, this parameter is one of the last that should be adjusted. Adjustment of the parameter toward negative values reduces the speed of the fuel metering valve response. Positive values increase the speed of the fuel metering valve response.
Air/Fuel Integral Gain
The "Air/Fuel Integral Gain" determines the response of the fuel metering valve. The response is for elimination of error in the difference that is between desired air/fuel ratio and actual air/fuel ratio.
The factory default setting is zero. This value should not require adjustment. If problems occur, this parameter is one of the last that should be adjusted. Adjustment of the parameter toward negative values reduces the response of the valve and positive values increase the response of the valve.
Speed Control
Low Idle Speed
Program this parameter to the desired low idle rpm.
Minimum High Idle Speed
Program this parameter to the desired minimum high idle rpm. The actual high idle speed is regulated by the desired speed input. The regulation is linear in proportion to the input. An input of 0 percent results in the minimum high idle rpm and an input of 100 percent results in the maximum high idle rpm.
The "Minimum High Idle Speed" and the "Maximum High Idle Speed" determine the slope of the desired speed input.
Maximum High Idle Speed
Program this parameter to the desired maximum high idle rpm. The actual high idle speed is regulated by the desired speed input. The regulation is linear in proportion to the input. An input of 0 percent results in the minimum high idle rpm and an input of 100 percent results in the maximum high idle rpm.
Engine Acceleration Rate
This parameter controls the rate for engine response to a change in the desired engine speed. For example, the engine can be programmed to accelerate at a rate of 50 rpm per second when the "Idle/Rated" switch is turned to the "Rated" position.
This parameter is also used for the engine rate of deceleration.
Desired Speed Input Configuration
This parameter determines the signal input to the ECM for control of the desired speed for the engine. The signal can be either 0 to 5 VDC or 4 to 20 mA.
Note: The ECM is not configured to accept a Pulse Width Modulated signal (PWM signal) for input of the desired engine speed. If you try to select a PWM, the ECM will reject the selection. Cat ET will generate an error if this parameter is selected.
Governor Type Setting
The "Governor Type Setting" parameter can be set to "Isochronous" or to "Droop". This setting is dependent upon the application of the engine.
Engine Speed Droop
This programmable parameter allows precise control of the engine speed droop. The "Governor Type Setting" parameter must be set to "Droop" in order for this parameter to be active.
Governor Gain Factor
This parameter is used in determining the engine rate of response to an engine load. Refer to Testing and Adjusting, "Engine Governing - Adjust" for the adjustment procedure for the governor.
Governor Stability Factor
The adjustment of "Governor Stability Factor" dampens the actuator response to changes in the engine load and speed. Increasing this value provides less damping. Decreasing the value provides more damping. To reduce governor overshoot, decrease the value. For reduction in undershoot of the governor, increase the value. Refer to Testing and Adjusting, "Engine Governing - Adjust" for the adjustment procedure for the governor.
Governor Compensation Factor
This parameter is used to adjust the time delay between the control signal and the movement of the actuator. If the compensation is too low, the engine speed will slowly hunt. If the compensation is too high, the engine speed will rapidly fluctuate. Refer to Testing and Adjusting, "Engine Governing - Adjust" for the adjustment procedure for the governor.
Auxiliary Proportional Governor Gain 1
This parameter is based on a proportional multiplier. The "Auxiliary Proportional Governor Gain 1" determines the speed of the throttle actuator response . The gain adjusts for the difference between the actual speed and the desired speed. Increasing this value provides a faster response to the difference between the actual speed and the desired speed.
Auxiliary Integral Governor Gain 1
This parameter is based on an integral multiplier. The "Auxiliary Integral Governor Gain 1" controls the speed for elimination of the error in the difference between the actual speed and the desired speed. Increasing this value provides less damping.
Auxiliary Derivative Governor Gain 1
This parameter is based on a derivative multiplier. The "Auxiliary Derivative Governor Gain 1" is used to adjust for the time delay between the control signal and the movement of the throttle actuator. If this value is too low, the engine speed will slowly hunt. If this value is too high, the engine speed will rapidly fluctuate.
Start/Stop Control
Driven Equipment Delay Time
The ECM accepts an input from the driven equipment that indicates when the equipment is ready for operation. When the input circuit is grounded, the driven equipment is ready. The ECM will not start the engine until this ECM input is grounded.
The ECM can be programmed to wait for a certain time after receiving a start command before starting the engine. This parameter allows the driven equipment to get ready for operation.
When the ECM receives a start command, the ECM will wait for the amount of time that is programmed into the "Driven Equipment Delay Time". If the "Driven Equipment Delay Time" elapses and the input circuit is not grounded, an event code is activated. The engine will not start.
If the "Driven Equipment Delay Time" is programmed to "0", the delay is disabled.
Crank Terminate RPM
The ECM disengages the starting motor when the engine speed exceeds the programmed "Crank Terminate RPM". This parameter is preset at the factory and this value should be sufficient for all applications.
Engine Purge Cycle Time
The "Engine Purge Cycle Time" is the duration of time for the engine to crank without fuel or spark during the crank cycle. The "Engine Purge Cycle Time" allows any unburned fuel to exit through the exhaust before the fuel and the ignition are enabled.
Cooldown Duration
When the ECM receives a stop request, the engine will continue to run in the "Cooldown Mode" for the programmed cooldown period. The cooldown mode is exited early if a request for an emergency stop is received by the ECM. If the "Cooldown Duration" is programmed to zero, the engine will immediately shut down when the ECM receives a stop request.
Cycle Crank Time
The "Cycle Crank Time" is the amount of time for activation of the starting motor, the ignition, and the gas shutoff valve during start-up. If the engine does not start within the specified time, the attempt to start is suspended for a rest cycle. The cycle is also equal to the "Cycle Crank Time".
Engine Overcrank Time
The "Engine Overcrank Time" determines the total length of time for the ECM to attempt to start the engine. This parameter is the sum of the cycle times for the crank cycle and the rest cycle. An event is generated if the engine does not start within this time. The ECM will terminate the attempt to start the engine.
Engine Speed Drop Time
This parameter is activated when the ECM receives the signal for stopping the engine. This input ensures the shutdown in case the Gas Shutoff Valve (GSOV) fails to close.
After the cooldown period has elapsed, the ECM removes power from the GSOV. The fuel is shut off from the engine. The ignition continues until the engine speed drops below 40 rpm. If the engine rpm does not drop at least 100 rpm within the programmed drop time, the ECM terminates the ignition. The ECM issues an emergency stop.
Engine Prelube
Engine prelube applies lubricating oil to the bearings before the engine is cranked. The postlube cycle lubricates the shaft bearings for the turbocharger during shutdown as the engine coasts to a stop . Enabling the engine prelube also enables the engine postlube.
Engine Prelube Time Out Period
This parameter is used by the ECM to protect the engine prelube pump. When the engine mode switch is changed from the STOP/RESET position to the START position, the prelube pump is energized by the ECM. A prelube pump pressure switch is used to detect oil pressure in the engine lubrication system. If oil pressure is not detected within the "Engine Prelube Time Out Period", the prelube cycle is terminated and an event code is generated.
Engine Postlube Duration
Once in the postlube cycle, the system runs the prelube pump for a programmable time. Enabling the engine prelube also enables the engine postlube.
The "Engine Prelube" parameter must be enabled and the "Engine Postlube Duration" parameter must be configured in order for the engine postlube to be enabled.
Monitoring and Protection
High Inlet Air Temp Engine Load Setpoint
The programmable setpoint is a value that separates low engine load from high engine load for events that are activated by high inlet air temperature. A status parameter in Cat ET displays the "Engine Load Factor". If the load factor is less than the setpoint and inlet air temperature reaches the trip point, an event code is activated. The code activated is High Inlet Air Temperature at Low Engine Load. If the load factor is greater than the setpoint and the inlet air temperature reaches the trip point, an event code is activated. The code activated is High Inlet Air Temperature at High Engine Load.
Passwords
Customer Passwords
The "Customer Password #1" parameter and the "Customer Password #2" parameter can be defined by the customer. The passwords are used to protect certain configuration parameters from unauthorized changes. Refer to Troubleshooting, "Customer Passwords" for details.
Security Access Parameters
Total Tattletale
This parameter is used to display the number of changes that have been made to the configuration parameters.
Parameter Table
System Configuration Parameters     | |||
---|---|---|---|
Parameter     | Available Range or Options     | Default     | Required Password     |
ECM Identification Parameters     | |||
Equipment ID     | 17 alphanumeric characters     | Blank     | None     |
Engine Serial Number     | 0XX00000 or XXX00000     | Blank     | None     |
Timing Control     | |||
First Desired Timing     | 10° to 40°     | 24°     | None     |
Second Desired Timing     | 10° to 40°     | 14°     | None     |
Desired Engine Timing Offset     | -6° to +6°     | 0°     | None     |
Air/Fuel Ratio Control     | |||
Fuel Quality (LHV)     | 8 to 102 MJ/Nm3 (200 to 2600 BTU/SCF)     |
35.5 MJ/Nm3 (900 BTU/SCF)     |
None     |
Gas Specific Gravity     | 0 to 1.990     | 0.600     | None     |
Fuel Specific Heat Ratio     | 1.000 to 2.000     | 1.400     | None     |
Emissions Feedback Mode Configuration     | NOX Feedback Feedback Disabled     |
NOX Feedback     | None     |
Desired Engine Exhaust NOX Level Setting (PPM)     | 40.0 to 600.0     | 40.0     | None     |
Air/Fuel Proportional Gain     | -50 to +50     | 0     | None     |
Air/Fuel Integral Gain     | -50 to +50     | 0     | None     |
Speed Control     | |||
Low Idle Speed (rpm) 1200 rpm applications     |
500 to 1100     | 1100     | None     |
Low Idle Speed (rpm) 1400 rpm applications     |
500 to 1100     | 1000     | None     |
Minimum Engine High Idle Speed (rpm) 1200 rpm applications     |
650 to 1500     | 1200     | None     |
Minimum Engine High Idle Speed (rpm) 1400 rpm applications     |
800 to 1500     | 1050     | None     |
Maximum Engine High Idle Speed (rpm) 1200 rpm applications     |
1450 to 1900     | 1600     | None     |
Maximum Engine High Idle Speed (rpm) 1400 rpm applications     |
1300 to 1500     | 1400     | None     |
Engine Acceleration Rate (rpm/sec)     | 1 to 50000     | 50     | None     |
Desired Speed Input Configuration     | 4-20 mA Input 0-5 VDC Input PWM     |
0-5 VDC Input     | None     |
Governor Type Setting     | Isochronous Droop     |
Droop     | None     |
Engine Speed Droop (Percent)     | 0 to 10     | 0     | None     |
Governor Gain Factor     | -50 to +50     | 0     | None     |
Governor Stability Factor     | -50 to +50     | 0     | None     |
Governor Compensation Factor     | -50 to +50     | 0     | None     |
Auxillary Proportional Governor Gain 1     | -50 to +50     | 0     | None     |
Auxilliary Integral Governor Gain 1     | -50 to +50     | 0     | None     |
Auxilliary Derivative Governor Gain 1     | -50 to +50     | 0     | None     |
Start/Stop Control     | |||
Driven Equipment Delay Time (seconds)     | 0 to 600     | 120     | None     |
Crank Terminate RPM     | 100 to 600     | 250     | None     |
Engine Purge Cycle Time (seconds)     | 0 to 60     | 0     | None     |
Cooldown Duration (minutes)     | 0 to 30     | 0     | None     |
Cycle Crank Time (seconds)     | 5 to 300     | 15     | None     |
Engine Overcrank Time (seconds)     | 5 to 360     | 120     | None     |
Engine Speed Drop Time (seconds)     | 5 to 120     | 15     | None     |
Engine Pre-Lube     | Disabled Enabled     |
Disabled     | None     |
Engine Pre-Lube Time Out Period (seconds)     | 30 to 300     | 120     | None     |
Engine Post-Lube Duration (seconds)     | 0 to 3600     | 0     | None     |
Monitoring and Protection     | |||
High Inlet Air Temp Engine Load Set Point (percent)     | 0 to 199     | 50     | None     |
Passwords     | |||
Customer Password #1     | N/A     | N/A     | None     |
Customer Password #2     | N/A     | N/A     | None     |
Security Access Parmeters     | |||
Total Tattletale     | N/A     | N/A     | N/A     |
Parameter Worksheet
Record the following information before you change any programmable parameter.
Engine Parameters     | |
---|---|
Equipment ID     |     |
Engine Serial Number     |     |
First Desired Timing     |     |
Second Desired Timing     |     |
Desired Engine Timing Offset     |     |
Fuel Quality (LHV)     |     |
Gas Specific Gravity     |     |
Fuel Specific Heat Ratio     |     |
Emissions Feedback Mode Configuration     |     |
Desired Engine Exhaust NOX Level Setting     |     |
Air/Fuel Proportional Gain     |     |
Air/Fuel Integral Gain     |     |
Low Idle Speed     |     |
Minimum Engine High Idle Speed     |     |
Maximum Engine High Idle Speed     |     |
Engine Acceleration Rate     |     |
Desired Speed Input Configuration     |     |
Governor Type Setting     |     |
Engine Speed Droop     |     |
Governor Gain Factor     |     |
Governor Stability Factor     |     |
Governor Compensation Factor     |     |
Auxillary Proportional Governor Gain 1     |     |
Auxilliary Integral Governor Gain 1     |     |
Auxilliary Derivative Governor Gain 1     |     |
Driven Equipment Delay Time     |     |
Crank Terminate RPM     |     |
Engine Purge Cycle Time     |     |
Cooldown Duration     |     |
Cycle Crank Time     |     |
Engine Overcrank Time     |     |
Engine Speed Drop Time     |     |
Engine Pre-Lube     |     |
Engine Pre-Lube Time Out Period     |     |
Engine Post-Lube Duration     |     |
High Inlet Air Temp Engine Load Set Point     |     |
Customer Password #1     |     |
Customer Password #2     |     |