3516B Engine for MT4400 Off-Highway Trucks: Engine Monitoring System

The Electronic Control Module (ECM) monitors various systems on the engine. The systems are monitored in order to detect any abnormal operating conditions. Specific functions that are monitored by the ECM include the following items:

Low engine oil pressure
High engine coolant temperature
Engine overspeed
Air inlet restriction
Engine fuel filter restriction
Engine oil filter restriction
Exhaust temperatures
Low coolant pressure
High aftercooler temperature
High crankcase pressure
Low engine oil level
Automatic altitude compensation

For details on the trip points, refer to the engines Troubleshooting manual.

Low Engine Oil Pressure

The ECM monitors the engine oil pressure by measuring an electrical signal from the oil pressure sensor. The oil pressure sensor is located on the filter outlet elbow. The filter outlet elbow is located on the front left corner of the engine. The ECM compares the actual engine oil pressure to an oil pressure map. The map is stored in the ECM memory. The map represents the minimum acceptable oil pressure. The map is based upon engine speed. If the oil pressure drops below the minimum acceptable level, the ECM will activate the low oil pressure warning. This warning will be displayed on the monitoring panel. Also, an event will be logged in the ECM memory. Factory passwords are required to clear logged events.

High Engine Coolant Temperature

The ECM monitors the engine coolant temperature by measuring an electrical signal from the engine coolant temperature sensor. The coolant temperature sensor is located in the housing for the coolant temperature regulators. The ECM compares actual coolant temperature to the maximum allowable limit. If the temperature of the engine coolant exceeds the trip point, the ECM will send the high coolant temperature warning to the monitoring panel. The warning will remain activated until the coolant temperature drops below the hysteresis. The event is logged in the permanent ECM memory. Factory passwords are required to clear this information.

Engine Overspeed

The ECM determines the engine speed by measuring an electrical signal from the speed/timing sensor. The sensor is located on the flywheel housing. The sensor is next to the left camshaft drive gear. If engine speed exceeds the trip point, an operator warning is given. The warning will remain active until the engine speed drops below the hysteresis. The peak engine overspeed is logged in the permanent ECM memory. The peak engine overspeed is logged as a histogram in order to quantify the magnitude of the engine overspeed. The histogram provides information in order to assess the potential level of engine damage. Factory passwords are required to clear this information.

Engine Fuel Filter Restriction

The engine utilizes two fuel pressure sensors, one being unfiltered fuel and the other being filtered fuel. The sensors are located in the fuel filter housing. The sensors provide signals to the ECM. The ECM sends a signal to the monitoring panel via the data link. The monitoring panel will warn the operator when the restriction of the fuel filter reaches an unacceptable level. An event will also be logged in the ECM. The event can be viewed with the electronic service tool. The event can also be cleared with the electronic service tool.

Engine Oil Filter Restriction

The ECM determines the restriction of the oil filter by calculating the difference between the filtered oil pressure and the unfiltered oil pressure.

Exhaust Temperatures

The engine ECM uses the exhaust temperature sensors for the turbocharger to provide a signal via the data link to the machine monitoring panel. The signal will indicate if the exhaust temperature to the turbocharger is at an acceptable level. The monitoring panel warns the operator if the exhaust temperature exceeds the trip point. A higher temperature will cause the ECM to derate the engine. The event will also be logged in the ECM. The event can be viewed with the electronic service tool. A factory password is required in order to clear this event with the electronic service tool. If the temperature is reduced below the specific range, derate is deactivated.

Low Coolant Pressure

The engine uses a coolant pressure sensor that is located in the piping after the outlet for the jacket water pump. The monitoring system compares the signal from the pressure sensor to a map of coolant pressure and engine speed. If the coolant pressure is not sufficient for the engine rpm, a warning is generated.

High Aftercooler Temperature

The ECM monitors the temperature of the engine aftercooler by measuring an electrical signal from the aftercooler coolant temperature sensor. The temperature sensor is located in the aftercooler outlet pipe. The ECM compares actual coolant temperature to the maximum allowable limit. The event is logged in the permanent ECM memory. Factory passwords are required to clear this information.

High Crankcase Pressure

The ECM gets data from the crankcase pressure sensor that is mounted on the camshaft cover. The ECM provides a signal via the data link to the machine monitoring panel. The monitoring panel will warn the operator if the crankcase pressure exceeds the trip point. An event will also be logged in the ECM. The event can be viewed with the electronic service tool. The event can also be cleared with the electronic service tool.

Low Engine Oil Level

The oil level sensor in the oil pan provides a signal to the ECM. The ECM provides a signal via the Cat^® Data Link to the monitoring panel. The monitoring panel will warn the operator of low engine oil level. An event will be logged in the ECM. The event can be viewed with the Electronic Service Tool. The event can be cleared with the Electronic Service Tool.

Automatic Altitude Compensation

The ECM automatically compensates for engine operation at higher elevations. The electronic control system derates the fuel delivery. The fuel delivery is a function of barometric pressure. The barometric pressure is sensed by the atmospheric pressure sensor. Derating by the ECM begins at a specific elevation. The rate of derating is based upon atmospheric pressure.

If the ECM senses an incorrect signal from the atmospheric pressure sensor and the turbocharger inlet pressure sensors. The ECM will default to the maximum altitude derate. The maximum altitude derate will be imposed until the problem is corrected.

MARYGAR