Alarm systems and shutdown systems contain sensors, contactors, and transducers. The sensors detect information about engine performance. The sensors are connected to contactors or transducers. The contactors and transducers are connected to a junction box.
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| Illustration 1 | g00702216 |
Setpoint - A setpoint is a critical limit of an operating parameter. A setpoint can be a temperature, a pressure, a level, a speed, etc. An alarm or a shutdown is activated if an operating parameter reaches a setpoint.
Contactor - A contactor is a switch that is controlled by temperature or pressure. The temperature or pressure that triggers the switch is set to a critical setpoint. If the setpoint is reached, an alarm or a shutdown will be activated.
Transducer - A transducer converts a mechanical stimulus into an electrical signal. An external power source is required.
Relay - A relay is an electromechanical device which uses a relatively small current to control an electromagnet. The electromagnet activates electrical contacts. The contacts open and the contacts close in order to switch larger electrical currents.
Protective systems are mandatory on Caterpillar 3600 Series Engines. Engine protection is provided by the Marine Monitoring System.
Marine Monitoring System
The Marine Monitoring System (MMS) uses a microprocessor to provide engine control and engine monitoring. The MMS enables an operator to use a display screen for controlling and monitoring engine operation.
When the package for annunciation is included, the operator is alerted to conditions that can cause alarms and shutdowns. The MMS can stop the engine if the engine operation reaches a setpoint that is programmed for shutdown.
Marine Engine Control Panel
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| Illustration 2 | g00744948 |
(1) Screen (2) Switch | |
Engine operation is monitored and controlled through the Marine Engine Control Panel. The Marine Engine Control Panel screen (1) is a touchscreen. The screen is used to configure the MMS for the particular engine. The configuration includes the following features:
- The optional gauges can be customized, enabled, or disabled.
- Metric units or English units can be selected for the display.
- The language that will be displayed can be selected. A keypad is required for this feature.
- The communication ports that are for external addresses can be selected and/or configured.
- The auxiliary gauges can be configured.
- Any auxiliary alarms can be configured.
An operator can choose from the following menu of monitoring features by using screen (1) :
Engine Overview - This window provides a general summary of the engine operation. This window graphically displays a top view of the engine. This window also displays the following operating parameters: rpm, engine hours, operating temperatures and operating pressures.
Auxiliary Gauges - This window displays the information that is provided by the auxiliary gauges.
Status and Auxiliary Outputs - This window is used to monitor the status of the communication for auxiliary parameters.
Alarm Annunciator - This window is used to display the precise cause of alarms that are active. This window can also display a history of all the alarms that have occurred.
Air and Fuel - This window displays a set of gauges that show the parameters of the air system and the fuel system.
Cooling System - This window graphically displays a diagram of the cooling circuit. The temperatures and pressures for the cooling system are also displayed. This window accesses a view of the gauges and a trend chart of the cooling system.
Exhaust - This window displays a summary of the exhaust port temperatures. This window also accesses the following parameters: exhaust port temperature deviation, exhaust manifold temperature and exhaust stack temperatures.
Lube Oil System - This window graphically displays a diagram of the lube system. The temperatures and pressures of the lube system are also displayed. This window accesses a view of the gauges and a trend chart of the lube system.
Alarms
An optional beacon and a horn are required for annunciation of alarms. To test the annunciation, the operator can turn switch (2) to the "TEST" position.
If an alarm occurs, the "Alarms" icon illuminates at the top of the screen. An "Alarm Annunciator" window appears on screen (1). To acknowledge the alarm, turn switch (2) to the "ACKNowledge" position. To view a graphic display of the particular alarm, touch the "SUMMARY ALARM" button that is illuminated in the "Alarm Annunciator" display window.
In addition to annunciation for undesirable engine operating conditions, an alarm will be displayed for the following conditions:
- A sensor output is out of specifications.
- A wire from a contactor has failed.
- A wire from a contactor has been removed.
For example, the pressure sensor for lube oil is a 4 to 20 mA output. If the output from the pressure sensor is 22 mA, an alarm for the sensor will be displayed.
If a wire for a contactor is normally open, the closed side of the contactor is used in order to determine the continuity of the circuit. If the wire has failed or if the wire has been removed, an alarm for the sensor will be displayed.
Sensor Locations
Air Restriction
Air restriction is monitored by a sensor. This sensor is located on the silencer of the turbocharger. This sensor measures the pressure of the air that enters the turbocharger.
Air restriction is an indication of the cleanliness of the air filter element. Air restriction increases as the air filter element becomes plugged. A visual indication on the sensor will inform the operator when the air restriction exceeds 3.7 kPa (15 inches of H2O).
Metal Particle Detector
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| Illustration 3 | g00745474 |
The metal particle detectors (1) are located near the engine oil pump. Detection of excessive metal particles in the engine oil can cause an alarm or a shutdown.
Aftercooler and Oil Cooler Water Temperature
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| Illustration 4 | g00744949 |
The sensor for aftercooler and oil cooler water temperature (2) is located at the outlet of the pump for the aftercooler and oil cooler water. A high aftercooler and oil cooler water temperature can activate an alarm.
Crankcase Pressure Switch
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| Illustration 5 | g00988205 |
Crankcase pressure is monitored by switch (3) that is located in the solenoid panel.
Rapid changes in crankcase pressure can indicate problems with the pistons, piston rings, and cylinder liners. High crankcase pressure can activate an alarm or a shutdown.
Exhaust Port Temperature for the Cylinder Head
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| Illustration 6 | g00987058 |
The exhaust temperature of each cylinder is monitored by sensors (4). If the exhaust temperature of any cylinder has a difference of more than 60 °C (140 °F) from the average exhaust temperature of all of the cylinders, an alarm is activated.
Fuel Pressure
The fuel pressure transducers are located at the transducer panel. The fittings for these transducers are located at the engine fuel rail inlet (5) and the fuel outlet (6). A decrease in fuel pressure can indicate a high fuel filter differential pressure. A low fuel pressure will activate an alarm.
Fuel Filter Differential Pressure
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| Illustration 7 | g00706985 |
Note: The fuel filters are not mounted on the engine. Therefore, the displayed values will take into account losses in the OEM supplied piping. This means that the values will vary between engines.
Fuel Temperature
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| Illustration 8 | g00706679 |
The sensor which is connected to fitting (7) is located at a fuel line on the engine side of the primary filter/water separator.
A loss of power will occur if the fuel temperature exceeds 29 °C (85 °F). A high fuel temperature can activate an alarm or a shutdown.
Inlet Manifold Air Pressure
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| Illustration 9 | g00707360 |
Two sensors help to monitor the inlet manifold air pressure. These sensors are connected to fittings (8). One fitting is located before the air coolers and one fitting is located after the air coolers.
Inlet Manifold Air Temperature
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| Illustration 10 | g00707365 |
The sensors for inlet manifold air temperature (9) are located both before the air coolers and after the air coolers. An excessive inlet manifold air temperature can indicate a problem with the aftercooler or the jacket water cooling system. A high inlet manifold air temperature can activate an alarm or a shutdown.
Jacket Water Pressure
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| Illustration 11 | g00707388 |
The fitting for jacket water pressure (10) is located at the outlet of the jacket water pump. Low jacket water pressure will activate an alarm or a shutdown.
Jacket Water Coolant Temperature
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| Illustration 12 | g00707395 |
Top view
Sensor (11) in the jacket water outlet piping monitors the jacket water coolant temperature. A high jacket water coolant temperature can activate an alarm or a shutdown.
Oil Filter Differential Pressure and Low Oil Pressure
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| Illustration 13 | g00707781 |
Fittings for the sensors that monitor the oil pressure
Fitting (12) is connected to the sensor that monitors the pressure of the oil before the oil has circulated through the engine oil filters. Fitting (13) is connected to the sensor that monitors the pressure of the oil after the oil has circulated through the engine oil filters. The difference of the two oil pressures is the oil filter differential pressure. The oil filter differential pressure increases as the oil filters become plugged. A high oil filter differential pressure will activate an alarm or a shutdown.
Fitting (14) is connected to the sensor that monitors the engine oil pressure. Low oil pressure can activate an alarm or a shutdown. The setpoints for the alarm and the shutdown depend on the engine rpm.
Oil Mist Detector
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| Illustration 14 | g00707784 |
Oil mist detector (15) monitors the concentration of oil mist in the crankcase. If the concentration of oil mist exceeds the alarm setpoint, an alarm is activated. If the concentration exceeds the shutdown setpoint, a shutdown will occur.
For more information, refer to Service Manual, RENR2225, "Oil Mist Detectors".
Oil Temperature
The sensor for the oil inlet temperature is located on the RH side of the cover. High oil temperature can activate an alarm or a shutdown.
Overspeed
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| Illustration 15 | g00705120 |
Engine rpm is monitored by a magnetic pickup (16) that senses the passage of the ring gear teeth on the flywheel (17). If the engine rpm exceeds 113 percent of the rated rpm, the fuel to the engine is shut off immediately.
Sea Water Pressure
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| Illustration 16 | g00706982 |
The sensor, which is connected to fitting (18), monitors the sea water pressure. This sensor is located at the outlet for the auxiliary water pump. Low sea water pressure will activate an alarm.
Starting Air Pressure
Note: The following sensor is used with "MMS" installation only.
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| Illustration 17 | g00707828 |
Sensor (19) monitors the air pressure that is available for starting the engine. If the air pressure is insufficient, an alarm is activated. The fitting is located after the air reducer.