The alarms and shutoffs are set at critical operating temperatures, pressures, or speeds in order to protect the engine from damage.
An alarm warns the operator when an abnormal operating condition occurs. The shutoffs shut down the engine if a more critical operating condition occurs. The shutoffs help to prevent damage to the engine.
Shutoffs may cause unburned gas to remain in the air inlet and in the exhaust manifold.
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Unburned gas in the air inlet and exhaust system may ignite when the engine is started. Personal injury and/or property damage may result. Before starting an engine that may contain unburned gas, purge the unburned gas from the air inlet and exhaust system. Refer to the topic on purging unburned gas in the "Starting the Engine" section. |
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If an engine protective device shuts off the engine, always determine the cause of the shutoff. Always make the necessary repairs before attempting to start the engine. Refer to Troubleshooting.
Become familiar with the following information:
- Types of the alarms and shutoffs
- Locations of the alarm and shutoff controls
- Conditions which cause each control to function
- Resetting procedure that is required before starting the engine
Testing Alarms and Shutoffs
Alarms must function properly in order to provide timely warning to the operator. Shutoffs help to prevent damage to the engine. It is impossible to determine if the engine protective devices are in good working order during normal operation. Malfunctions must be simulated in order to test the engine protective devices.
| NOTICE |
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During testing, abnormal operating conditions must be simulated. The tests must be performed correctly in order to prevent possible damage to the engine. |
Periodic testing of engine protective devices for proper operation is recommended maintenance. To prevent damage to the engine, only authorized service personnel or your Caterpillar dealer should perform the tests.
Prevention of Start-up
The engine will not start if any of the conditions that cause a shutoff are present. The following conditions will also prevent starting of the engine:
- An input from the driven equipment prevents starting.
- An overcrank occurs.
- The prelube pressure is low. Operation of the prelube pump exceeds the programmed period of time.
If any of these situations occur, the following conditions must be met before the engine can be started:
- The condition that prevented starting is not present.
- The engine control switch is turned to the "OFF/RESET" position.
Setpoints for Alarms and Shutoffs
Some of the setpoints for the alarms and shutoffs can be programmed with the Caterpillar Electronic Technician (ET). Some of the parameters cannot be programmed.
The setpoints are programmed at the factory. The status for most of the parameters is ON. Table 1 lists the default setpoints of the warnings and shutoffs for G3500B Engines.
For information on programming of parameters, refer to Systems Operation/Testing and Adjusting.
| Default Setpoints of the Warnings and Shutoffs for G3500B Engines | ||
|---|---|---|
| Parameter | Setpoint for Warnings | Setpoint for Shutoff |
| Cooling System | ||
| "High Jacket Water Inlet Pressure" (1) (2) | n/a | 462 ± 41 kPa (67 ± 6 psi) |
| "Low Jacket Water Pressure Shutdown" (outlet) (1) (2) | - | (5.6655 × the jacket water coolant temperature (°C)) - 420.46 |
| "High Engine Coolant Temperature" (3) | 109 °C (229 °F) (1) |
113 °C (235 °F) (4) |
| "Low Engine Coolant Temperature" (1) (3) | 5 °C (41 °F) |
n/a |
| Electrical System | ||
| "High System Voltage" (1) (2) | 34 volts | n/a |
| "Low System Voltage" (1) (2) | 20 volts | 18 volts |
| Exhaust System | ||
| "Cylinder #X High Exhaust Port Temp" (1) (3) | 650 °C (1202 °F) |
665 °C (1229 °F) |
| "Cylinder #X Exhaust Port Temp Deviating High" (1) (3) | 50 °C (122 °F) |
150 °C (302 °F) |
| "Cylinder #X Exhaust Port Temp Deviating Low" (1) (3) | 50 °C (122 °F) |
150 °C (302 °F) |
| "High Turbo Turbine Inlet Temperature" (3) (4) | 495 °C (923 °F) |
650 °C (1202 °F) |
| "High Turbo Turbine Outlet Temperature" (3) (4) | 495 °C (923 °F) |
650 °C (1202 °F) |
| "Low Turbo Turbine Inlet Temperature" (3) (4) | 250 °C (482 °F) |
100 °C (212 °F) |
| "Low Turbo Turbine Outlet Temperature" (3) (4) | 250 °C (482 °F) |
100 °C (212 °F) |
| Fuel System | ||
| "Fuel Energy Content Setting High" (1) (2) | The fuel correction factor is greater than 125% for 20 seconds. | n/a |
| "Fuel Energy Content Setting Low" (1) (2) | The fuel correction factor is less than 75% for 20 seconds. | n/a |
| "High Fuel Temperature" (1) (3) | 60 °C (140 °F) |
n/a |
| "Fuel Quality Out of Range" (1) (2) (5) | n/a | The actual fuel energy content is not within the range that is programmed. |
| "Low Gas Fuel Differential Pressure" (1) (3) | 5 kPa (0.7 psi) |
n/a |
| "High Gas Fuel Differential Pressure" (1) (3) | 35 kPa (5 psi) |
n/a |
| Electrohydraulic Actuator System | ||
| "Low Electrohydraulic Oil Pressure" (1) (2) | n/a | 700 ± 103 kPa (102 ± 15 psi) |
| Ignition System | ||
| "Cylinder #X Detonation" (1) (2) | n/a | Detonation continues after the electronic control module has retarded the timing by 6 degrees. |
| Inlet Air System | ||
| "High Inlet Air Temperature at High Engine Load" (1) (3) | 53 °C (127 °F) |
57 °C (135 °F) |
| "High Inlet Air Temperature at Low Engine Load" (1) (3) | 69 °C (156 °F) |
73 °C (163 °F) |
| Setpoint of Load | 50% | 50% |
| Lubrication System | ||
| "High Oil Filter Differential Pressure" (1) | 103 kPa (15 psi) (3) |
138 kPa (20 psi) (6) |
| "Low Oil Filter Differential Pressure" (1) | 35 kPa (5 psi) (3) |
7 kPa (1 psi) (6) |
| "Low Engine Oil Pressure" (1) (2) Rated speed |
310 kPa (45 psi) |
276 kPa (40 psi) |
| "Low Engine Oil Pressure" (1) (2) Idle speed |
138 kPa (20 psi) |
103 kPa (15 psi) |
| "High Engine Oil Temperature" (1) | 102 °C (216 °F) (3) |
104 °C (219 °F) (6) |
| Miscellaneous | ||
| "Customer Shutdown Requested" | n/a | The input requests a shutdown. |
| "Driven Equipment Not Ready" | n/a | |
| "Engine Overspeed Shutdown" (1) (6) | n/a | 118 percent of the rated rpm (1) |
| "High Jacket Water to Engine Oil Temperature Differential" (1) | 14 °C (25 °F) (3) |
20 °C (36 °F) (6) |
| Methane Gas Detector | n/a | The hydrocarbon content in the air rises above 2 percent. (7) |
| ( 1 ) | The default status is ON. |
| ( 2 ) | This parameter cannot be programmed. |
| ( 3 ) | A customer password is required for reprogramming this parameter. |
| ( 4 ) | The default status is OFF. |
| ( 5 ) | The acceptable range is 300 to 2400 BTU. |
| ( 6 ) | A factory password is required for reprogramming this parameter. |
| ( 7 ) | For information regarding calibrating the methane gas detector, refer to this Operation and Maintenance Manual, "Methane Gas Detector". |