3512C HD Locomotive Engine Caterpillar

Cat Monitoring System

The engine is equipped with a programmable Cat Monitoring System. The Electronic Control Module (ECM) monitors the operating parameters of the engine. The ECM can initiate responses if a specific engine parameter exceeds an acceptable range. Three possible responses may be available for each parameter: "WARNING", "DERATE" and "SHUTDOWN". Some of the responses are not available for some of the parameters. An ET service tool is used to perform the following activities:

• Select the available responses.

• Program the level for monitoring.

• Program delay times for each response.

The default settings for the parameters are programmed at the factory. To accommodate unique applications and sites, the parameters may be reprogrammed with an ET service tool.

The screens of the ET service tool provide guidance for the programming. The following options can be programmed "ON" or "OFF": "WARNING", "DERATE" and "SHUTDOWN".

The screens of the ET service tool also provide guidance for changing setpoints. For information on programming the Caterpillar Monitoring System, use the appropriate ET service tool and see the Service Manual, "Troubleshooting" module.

The Cat Monitoring System is enabled after the engine is started. When the engine rpm exceeds 50 rpm below low idle, the ECM begins checking parameters. The ECM monitors the parameters in order to determine if the parameters exceed the setpoints.

An event indicates an abnormal engine operating condition. If the monitoring system initiates a warning, a deration, or a shutdown, the event is logged into the ECM. The event is logged even if the parameter is programmed "OFF". If a setpoint for a parameter is exceeded, the event will be logged.

A diagnostic code indicates a problem with the monitoring system. Any failure of a sensor will result in disabling the corresponding portion of the monitoring system. The failure of a sensor will cause an "ACTIVE" diagnostic code for the sensor. Event codes are not logged for occurrences of diagnostic codes.

The derating is cumulative. For example, a derating of 5 percent followed by a derating of 2 percent results in a total derating of 7 percent. If the conditions that cause the derating are not corrected, the derating will continue to a maximum of 25 percent.

Default Settings for the Cat Monitoring System

Derate - Derate is a reduction of engine horsepower in response to an abnormal operating condition.

Setpoint - The setpoint is a specific value which can activate the following responses: warning, deration and shutdown. The setpoint can be a pressure, a speed, a temperature, or a voltage.

Hysteresis - Hysteresis is the change in the signal from a sensor that is tolerated by the ECM. Hysteresis is the difference between the setpoint that activates a response and the value that deactivates the response. For example, a warning for low voltage can activate if a value below 20 V is detected by the ECM. The voltage must rise to 22 V in order to clear the warning. The hysteresis is the 2 V that are above the 20 V.

Voltage

The ECM automatically warns the operator of low system voltage. The default settings that are programmed at the factory are listed in Table 1.

If the voltage is below 20 V for 10 seconds, a warning will occur. To deactivate the warning, the voltage must rise above 22 V.

The setpoint can be programmed to a value between 20 and 22 V.

Engine Oil Pressure

The ECM automatically performs the following functions for low engine oil pressure:

• Warning

• Shutdown

The strategy is based on a map of the engine oil pressure versus the engine rpm. See Illustration 1. The default settings that are programmed at the factory are listed in Table 2.

Illustration 1	g00768888
Map of the engine oil pressure versus the engine rpm (Y) Engine oil pressure in kPa (X) Engine rpm (1) Hysteresis (2) Minimum engine oil pressure

If the engine oil pressure is below the minimum pressure for 4 seconds, a warning will occur. To deactivate the warning, the engine oil pressure must rise above the hysteresis that is set in the map.

If the engine oil pressure is below the minimum pressure for 9 seconds, a shutdown will occur.

The map cannot be reprogrammed.

High Coolant Temperature

The ECM will automatically perform the following functions for high coolant temperature:

• Warning

• Derating

• Shutdown

The default settings that are programmed at the factory are listed in Table 3.

If the coolant temperature is above 102 °C (216 °F) for 5 seconds, a warning will occur. The coolant temperature must be below 97 °C (207 °F) in order to deactivate the warning.

If the coolant temperature is above 105° C (221° F) for 5 seconds, a derating will occur. A continuous 25 percent derating is reached in 480 seconds. When the coolant temperature is less than 102 °C (216 °F), the percent of the derating decreases. The percent of the derating decreases until the capability of providing full power is restored. However, if the coolant temperature rises above the setpoint again, the derating will resume.

If the coolant temperature is above 107 °C (225 °F) for 10 seconds, a shutdown will occur.

Note: The default setting for the delay of the derating is programmed to the maximum value of 30 seconds. The delay for the shutdown is 10 seconds. These settings result in a shutdown that occurs before a derating. These settings are programmed because most customers prefer a shutdown for high coolant temperature. The settings can be programmed to different values.

Note: If the shutdown is deactivated, go to notch zero setting in the ECM. This setting will cut power traction and keep the engine running with the auxiliaries. This operation will provide air pressure for the braking system and operate the radiator fans.

The setpoint can be programmed in the range of 90 to 102 °C (194 to 215 °F).

Low Coolant Temperature

The ECM will automatically warn the operator of low coolant temperature. The default settings that are programmed at the factory are listed in Table 4.

To activate this strategy, the engine must operate for a minimum of 10 minutes at an average load of 20 percent or more. If the average load is 20 percent or more and the coolant temperature is below 60° C (140° F) for 5 seconds, a warning will occur. To deactivate the warning, one of the following conditions must occur:

• The average load for 10 minutes must decrease to less than 20 percent.

• The coolant temperature must rise above 85 °C (185 °F).

The setpoint can be programmed in the range of 63 to 85 °C (145 to 185 °F).

Note: For the calculation of the load, the position of the fuel rack at low idle rpm (no load) is zero percent. The position of the fuel rack at rated rpm (rated load) is 100 percent.

Note: The low coolant temperature is monitored in order to detect a failure of the water temperature regulators. This feature is not intended to monitor the operation of jacket water heaters.

Overspeed

The ECM will automatically perform the following functions if an engine overspeed occurs:

• Warning

• Shutdown

Different setpoints are based on the engine application and the engine rating. The default settings that are programmed at the factory are listed in Table 5.

If the engine speed exceeds the setpoint rpm, a warning and a shutdown will occur. The fuel will be shut off and the air shutoff will be activated.

The air shutoff must be reset before the engine is restarted. Ensure that both of the air shutoffs are reset.

Note: The default settings for the warning and for the shutdown are equal. Therefore, the warning and the shutdown occur simultaneously. These settings were selected in order to log both a warning and a shutdown: furthermore, an overspeed condition can occur rapidly.

The setpoints can be programmed to a value between 1200 and 2400 rpm.

Inlet Air Restriction

The ECM will automatically perform the following functions if a high inlet air restriction occurs:

• Warning

• Derating

The strategy is applied to the right side air filter and/or the left side air filter. The default settings that are programmed at the factory are listed in Table 6.

If the inlet air restriction is above 7 kPa (1 psi) for 5 seconds, both a warning and a derating will occur. The continuous schedule of the derating is 2 percent per 1 kPa (0.15 psi). The maximum derating is 50 percent at 25 kPa (3.6 psi).

The derating remains at the maximum level until the situation is corrected. To reset the derating to zero percent, remove power from the ECM. The ECM will reset when power is returned.

Altitude

The ECM automatically compensates for engine operation at higher elevations. The ECM derates the fuel delivery according to the barometric pressure. The barometric pressure is sensed by the atmospheric pressure sensor. The atmospheric pressure affects the performance of the engine. Derating the fuel delivery maintains the temperatures of the exhaust gas within acceptable limits.

The derating of the engine starts at a specific barometric pressure. The barometric pressure is equal to the atmospheric pressure of an elevation. The atmospheric pressure is specific for the engine and for the engine rating. The default settings that are programmed at the factory are listed in Table 7.

If the barometric pressure is below the setpoint, a warning and a derating will occur. The continuous schedule of the derating is 3 percent per 1 kPa (0.15 psi) of pressure below the setpoint. The maximum derating is 35 percent.

Exhaust Temperature

The ECM will automatically perform the following functions if a high exhaust temperature occurs:

• Warning

• Derating

The strategy is applied to the right side exhaust manifold and/or the left side exhaust manifold. The default settings that are programmed at the factory are listed in Table 8.

If the exhaust temperature is above the setpoint for the warning for 5 seconds, a warning will occur.

If the exhaust temperature is above the setpoint for the derating for 5 seconds, the derating will occur.

The derating reduces the power by 2 percent. This event is followed by a 15 second delay. If the exhaust temperature is not reduced below the setpoint after the 15 second delay, the engine is derated another 2percent.

When the exhaust temperature is reduced to less than the setpoint, 2 percent of the power is restored for every 15 seconds. This operation continues until full power is restored. However, if the exhaust temperature rises above the setpoint again, the derating resumes.

Oil Filter Differential Pressure

The ECM automatically warns the operator of high oil filter differential pressure. The default settings that are programmed at the factory are listed in Table 9.

If the oil filter differential pressure is above 105 kPa (15 psi) for 5 seconds, a warning will occur. To deactivate the warning, the oil filter differential pressure must be below 95 kPa (13.5 psi).

Fuel Filter Differential Pressure

The ECM automatically warns the operator of high fuel filter differential pressure. The default settings that are programmed at the factory are listed in Table 10.

If the fuel filter differential pressure is above 70 kPa (10 psi) for 5 seconds, a warning will occur. To deactivate the warning, the fuel filter differential pressure must be below 60 kPa (8.7 psi).

Crankcase Pressure

The ECM will automatically perform the following functions if high crankcase pressure occurs:

• Warning

• Derating

• Shut down

The default settings that are programmed at the factory are listed in Table 11.

If the crankcase pressure is above 2 kPa (0.3 psi) for 3 seconds, a warning will occur. To deactivate the warning, the crankcase pressure must be below 1.75 kPa (0.254 psi).

If the crankcase pressure is above 3.5 kPa (0.51 psi) for 5 seconds, a derating will occur. The continuous schedule of the derating will reach 15 percent in 480 seconds.

When the crankcase pressure is less than 2.7 kPa (0.39 psi), the percent of the derating is decreased until full power is restored. However, if the crankcase pressure rises above the setpoint again, the derating resumes.

If the crankcase pressure is above 5 kPa (0.73 psi) for 3 seconds, a shutdown will occur.

Note: The default settings result in a shutdown that occurs before a derating. These settings were selected for the reason that high crankcase pressure can occur rapidly. The settings can be reprogrammed.

Aftercooler Coolant Temperature

Note: The following information concerns engines with separate circuit aftercooling. For engines with jacket water aftercooling, monitoring of the aftercooler coolant temperature is disabled. However, the jacket water coolant temperature is monitored for all engines.

The ECM will automatically perform the following functions when high aftercooler coolant temperature occurs:

• Warning

• Derating

• Shut down

The default settings that are programmed at the factory are listed in Table 12.

Note: If the coolant temperature rises above 70 °C (158 °F), the maps of engine performance will automatically decrease the available power. The power is reduced to the rating for jacket water aftercooling. This reduction is not part of the 25 percent derating.

If the aftercooler coolant temperature is above 102 °C (215 °F) for 5 seconds, a warning will occur. To deactivate the warning, the aftercooler coolant temperature must be below 99 °C (210 °F).

If the aftercooler coolant temperature is above 107 °C (225 °F) for 5 seconds, a derating will occur. The continuous schedule of the derating will reach 25 percent in 480 seconds.

When the aftercooler coolant temperature is less than 104 °C (220 °F), the percent of the derating is decreased until full power is restored. However, if the aftercooler coolant temperature rises above the setpoint again, the derating resumes.

If the aftercooler coolant temperature is above 107 °C (225 °F) for 5 seconds, a shutdown will occur.

Override Switch

Note: Normally, the override switch is not supplied by Caterpillar.

The override switch enables the operator to override the monitoring system. The switch is provided for use in emergency situations when an engine must be operated at full capability immediately. The switch can also be used to prevent an engine shutdown during critical maneuvers. Use of the switch will override conditions of derating and/or shutdown. However, an overspeed shutdown cannot be overridden.

The switch is a two-position "ON/OFF" switch. When the switch is in the "OFF" position, the monitoring system will operate normally.

When the switch is in the "ON" position, the monitoring system is disabled. All of the warnings will continue to function normally. No derating will occur. The overspeed shutdown will continue to function normally. Except for the overspeed shutdown, no shutdowns will occur. If the engine has already had a shutdown, the engine can be restarted when the switch is in the "ON" position. The alarm conditions and events will continue to function normally.

An event will be logged in the ECM when the switch is placed in the "ON" position. Also, an event will be logged in the ECM when the switch is returned to the "OFF" position. No delay is required for use of the switch.