The sensors also enable the module to activate alarms, impending shutdowns, and shutdowns in response to abnormal operation. The functions of the sensors are described below.
Air Filter Differential Pressure
The air filter differential pressure sensor monitors the level of restriction across the air filter by comparing the sensors value to the value provided from the ambient pressure sensor. Restriction levels greater than 7 KPA will generate a warning event.
The sensor monitors the local atmospheric pressure in absolute.
Note: The crankcase pressure sensor is only available for the G3512H engine application.
When the engine crankcase pressure increases or decreases to the set trip points, the ECM will generate a warning or a shutdown. The trip point can be programmed with a customer password. The warning and shutdown are always active.
Note: Low pressure only has a trip point for warning level.
The sensor measures the level of nitrogen oxides (NOx) existing the engine exhaust gas. The desired rate of exhaust level NOx is determined via a closed loop system, utilizing a NOx sensor for feedback.
Throttle Differential Pressure Sensor
This sensor monitors the pressure drop across the throttle valve.
Compressor Outlet Pressure Sensor
This sensor monitors the pressure of the air/fuel mixture from the turbocharger compressor outlet.
Compressor Outlet Temperature Sensor
This sensor monitors the temperature of the air/fuel mixture from the turbocharger compressor outlet.
Coolant Pressure Sensor (Outlet)
A pressure sensor is at the outlet for the engine jacket water. If the outlet pressure is too low, the ECM will activate a shutdown.
Pressing this button causes a shutdown.
Intake Manifold Air Pressure Sensor
This sensor is connected to the inlet manifold. The sensor monitors the absolute manifold pressure. Absolute pressure is the atmospheric pressure plus the gauge pressure. The information is used by the ECM to calculate the air flow. To observe the output value of the sensor, use Cat ET to view the "Inlet Manifold Air Pressure (abs)".
An oil temperature sensor measures the engine oil temperature. A high oil temperature will activate an alarm or a shutdown. The trip points can be programmed with the Caterpillar Electronic Technician (Cat ET). To observe the output value of the sensor, use Cat ET to view the "Engine Oil Temperature" parameter.
Pressure Sensor for the Coolant Pump (Inlet)
A pressure sensor is at the inlet for the engine jacket water. If the inlet pressure is too high, the ECM will activate a shutdown. To observe the status of the sensor, use the Caterpillar Electronic Technician (Cat ET) to view the "Engine Coolant Pressure" parameter.
The transducer for timing the engine is connected to this connector.
The engine oil pressure is measured before the oil filters and after the oil filters . An alarm or a shutdown can be activated by any of the following occurrences: low filtered oil pressure, low oil filter differential pressure, and high oil filter differential pressure. The trip point for the activation of a warning or a shutdown for oil filter differential pressure can be programmed with Cat ET. To observe the value of the output of the sensor, use Cat ET to view the "Engine Oil Pressure" or the "Pre-Filter Engine Oil Pressure" parameter.
The temperature sensor is located in the water temperature regulator housing. To monitor the coolant temperature, the element must be in contact with the coolant. Otherwise, the sensor will not function properly. A high coolant temperature will activate an alarm or a shutdown. A low coolant temperature will only activate an alarm. The trip points for the activation can be programmed with Cat ET. The engine can be restarted after a shutdown due to high engine coolant temperature. However, another shutdown will occur after 1 minute if the temperature remains high. To observe the value of the output of the sensor, use Cat ET to view the "Engine Coolant Temperature" parameter.
Intake Manifold Air Temperature Sensor
A sensor for monitoring the intake manifold air temperature. Excessive intake air temperature can activate an alarm or a shutdown during high load or low load operation. The trip points for activation can be programmed with Cat ET. To observe the value of the output of the sensor, use Cat ET to view the "Intake Air Temperature" parameter.
The engine is equipped with a crank and cam position sensor.
The primary speed/timing sensor generates a signal by detecting the movement of the teeth that are on the crankshaft timing ring. The signal that is generated by the speed/timing sensor is transmitted to the ECM. The ECM uses the signal from the speed/timing sensor to calculate the position of the crankshaft.
The secondary speed/timing sensor generates a signal that is related to the camshaft position. The secondary speed/timing sensor detects the movement of the teeth on the timing ring for the camshaft. The signal that is generated by the speed/timing sensor is transmitted to the ECM. The ECM calculates the speed and the rotational position of the engine by using the signal. The secondary speed/timing sensor is required for starting purposes.
To determine ignition timing, the ECM must be able to determine the position of the cam and crankshaft by monitoring the engine speed/timing sensors.
Crank Sensor - Secondary measurement to determine engine position during cranking. The sensor is the primary source for measured speed and position after engine position has been confirmed by the camshaft speed timing sensor during cranking.
Cam Sensor- Primary measurement to determine engine position during cranking. The sensor is the secondary source for measured speed and position after it has determined engine position during cranking.
The detonation sensors monitor the engine for mechanical vibrations. Each sensor monitors two cylinders. The sensor produces a voltage signal that is proportional to the engine detonation. This information is processed by the ECM to determine detonation levels. To eliminate detonation, the ECM retards the timing of the cylinder. If detonation continues, the ECM will shut down the engine. To observe the value of the output of the sensors, use Cat ET to view the "Cylinder #X Detonation Level". The "X" is the number for the particular cylinder.