3176B INDUSTRIAL ENGINE Caterpillar

Section 7: Glossary of Terms

Usage:

Active Diagnostic Code: Describes a condition that is currently present to alert the operator or service Technician of an abnormal engine operation parameter. Refer to Diagnostic Fault Code.
Aftermarket Device: As used here, a device or accessory installed by the customer or vessel OEM after the engine is delivered.
Air To Air Aftercooler (ATAAC): A means of cooling inlet air after the turbocharger, using ambient air for cooling. The inlet air is passed through an aftercooler (heat exchanger) mounted in front of the radiator before going to the inlet manifold.
Alternating Current (AC): The direction of current flow changes (alternates) regularly and constantly in a circuit.
American Wire Gauge (AWG): A measure of the diameter (and therefore the current carrying ability) of electrical wire. The smaller the AWG number, the larger the wire.
Atmospheric Pressure Sensor: The Atmospheric Pressure Sensor monitors atmospheric pressure. Atmospheric Pressure sensing is used to reduce smoke emissions at high altitudes. The ECM optimizes timing bases on engine operating conditions. The sensor operates on +5 VDC supplied through pin-36 of the ECM connector J2/P2.
Boost Pressure Sensor: Refer to Inlet Air Manifold Pressure Sensor.
Breakout T Harness: A test harness designed to connect into a machine or engine harness which allows normal circuit operation while providing a breakout or T to measure signals.
Bypass Circuit: A circuit, usually temporary, to substitute for an existing circuit, typically for test purposes.
Calibration: As used here, is an electronic adjustment of a sensor signal.
CAT Data Link: A two wire electrical connection for communication with other microprocessor based devices such as EMS II. The Data Link is also the serial communication medium used for programming and troubleshooting with Caterpillar Electronic Service Tools.
Caterpillar Engine Monitoring: The part of the Electronic Control Module that monitors Coolant Temperature, Filtered Fuel Pressure, Inlet Manifold Air Temperature and Coolant Level to alert the operator of detected problems. The Coolant Temperature, Inlet Manifold Air Temperature, and Filtered Fuel Pressure Sensors are supplied by Caterpillar and monitored by the ECM. The Coolant Level Sensor is vessel OEM installed, but still monitored by the ECM. Aftermarket engine monitoring systems do not interface with the Caterpillar Electronic Engine Control Module.
Check Engine Lamp: Sometimes referred to as the "Diagnostic Lamp", it is used to alert the operator of the presence of an active event and is used to flash a diagnostic code.
Code: Refer to Diagnostic Fault Code.
Cold Mode: A mode of engine operation where the timing is retarded and the low idle may be raised for engine protection, reduced smoke emissions and faster warm up time.
Component Identifier (CID): Two or three digit code which is assigned to each component to identify data via data link to ECM.
Coolant Level Sensor: This OEM installed sensor detects the absence/presence of coolant at the probe and sends a signal to the ECM.
Coolant Temperature Sensor: The Coolant Temperature Sensor measures the temperature of the engine coolant. The ECM uses this information to determine the mode of operation and if Caterpillar Engine Monitoring is not programmed to the OFF mode, to notify the operator of excessive engine temperature. The sensor operates on +5 VDC supplied through pin-36 of the ECM connector J2/P2.
Customer Specified Parameter: A parameter value that can be changed and whose value is set by the customer.
Data Link: Refer to CAT Data Link.
Desired RPM: An input to the electronic governor within the ECM. The electronic governor uses inputs from the Throttle Position Sensor, Engine Speed/Timing Sensor and Customer Parameters to determine "Desired RPM".
Diagnostic Flash Code: These codes are flashed out using the Check Engine/Diagnostic Lamp to indicate an electronic system malfunction or an event detected by the Electronic System.
Diagnostic Lamp: Sometimes referred to as the "check engine light", it is used to warn the operator of the presence of an active diagnostic code.
Direct Current (DC): The type of current where the direction of current flow is consistently in one direction only.
Duty Cycle: Refer to Pulse Width Modulation.
Electronic Control Analyzer & Programmer (ECAP): An electronic service tool developed by Caterpillar used for programming and diagnosing a variety of Caterpillar electronic controls using RS-232 data link.
Electronic Control Module (ECM): The engine control computer that provides power to the truck engine electronics. It accepts inputs that monitor and outputs that control or change to act as a governor to control engine rpm.
Electronic Engine Control: The complete electronic system that monitors and controls engine operation under all conditions.
Electronic Technician (Cat ET): A software program to run on a service tool like a personal computer (PC).
Estimated Dynamic Timing: The ECM estimation of actual injection timing.
Event Code: These codes indicate an event that describe an abnormal engine condition, such as an Idle Shutdown Occurrence. They are not necessarily (or usually) an indication of problems within the Electronic System.
Failure Mode Identifier (FMI): Type of failure the component experienced (adopted from SAE standard practice J1587 diagnostics).
Fault Code: Sometimes referred to as a diagnostic fault code. These codes indicate an electronic system malfunction or problem with the engine electronic system.
Flammstart: The flammstart is a separate system that may operate independent of the engine control. However, to optimize the cold start strategy may be desired to turn off fuel injection to heater plug before the flammstart system normally would. With the Flammstart relay connected, the ECM will disable the Flammstart after inlet air reaches 55°C. This reduces the chance of the flame becoming counterproductive as it consumes oxygen. For more information on Flammstart, refer to SEHS9551, Inlet Manifold Heater Operation Manual. The Inlet Manifold will turn off if the engine speed is < 500 rpm and the Inlet Air Temperature is < 55°C (131°F).
Filtered Fuel Pressure Sensor: This sensor measures engine filtered fuel pressure and sends a signal to the ECM as part of Caterpillar Engine Monitoring.
Flash Code (FC): The Caterpillar proprietary code numbers which are flashed out on the diagnostic lamp.
Flash Programming: A way of programming or updating an ECM with an Electronic Service Tool over the data link.
Fuel Position: An internal signal within the ECM, from the Electronic Governor to Fuel Injection Control. It is based on Desired RPM, FRC Fuel Position, rated fuel position and engine rpm.
Fuel Ratio Control (FRC): FRC Fuel Pos is a limit based on control of the fuel to air ratio and is used for emissions control purposes. When the ECM senses a higher boost pressure (more air into cylinder), it increases the "FRC Fuel Pos" limit (allows more fuel into cylinder).
Fuel Temperature Sensor: The Fuel Temperature Sensor monitors the fuel temperature and is used by the ECM to adjust the ECM calculated fuel rate. The ECM compensates for temperature changes and adjusts the actual fuel rate for fuel temperature above 30°C (86°F). The sensor is also used to warn the operator of an excessive fuel temperature. The Fuel Temperature Sensor operates independently of Caterpillar Engine Monitoring. If Engine Monitoring is programmed to OFF, the Fuel Temperature Sensor is not ignored or affected. The sensor operates on +5 VDC supplied through pin-36 of the ECM connector J2/P2.
Full Load Setting (FLS): Number representing fuel system adjustment made at the factory to "fine tune" the fuel system maximum fuel delivery. Correct value for this parameter is stamped on the engine information ratings plate. This parameter must be programmed or a Diagnostic Code 253-02 Check Customer Or System Parameters (56) will be generated.
Full Torque Setting (FTS): Similar to Full Load Setting. This parameter must be programmed or a Diagnostic Code 253-02 Check Customer Or System Parameters (56) will be generated.
Harness: The wiring bundle (loom) connecting all components of the Electronic System.
Hertz (Hz): Measure of frequency in cycles per second.
Histogram: A bar graph indicating the relative frequency of machine operation in specific operating ranges.
Idle RPM Limit: Programmable parameter which indicates the maximum allowable engine rpm when an engine rpm is set using the Cruise Control On/Off switch and SET/RESUME switch.
Inlet Air Manifold Pressure: The ECM monitors Inlet Air Manifold Pressure (boost) through a sensor located inside the right side of the engine in the inlet manifold. Boost pressure is determined from the difference in pressure between Inlet Air Manifold Pressure and the Atmospheric Pressure. Boost pressure is used to reduce smoke emissions during acceleration. The ECM limits the amount of fuel injected until certain pressures are reached. The Inlet Air Manifold Pressure Sensor can measure pressure from 20 kPa (3 psi) to 340 kPa (49 psi). The sensor operates on +5 VDC supplied through pin-36 of the ECM connector J2/P2.
Inlet Air Manifold Temperature Sensor: The Inlet Air Manifold Temperature Sensor measures the temperature of the inlet air manifold. The ECM monitors the Inlet Air Manifold Temperature Sensor to adjust injection timing and to warn the operator of an excessive Inlet Air Manifold Temperature for engine monitoring. The Inlet Air Manifold Temperature Sensor does not affect Cold Mode low idle engine rpm like the Coolant Temperature Sensor. The sensor operates on +5 VDC supplied through pin-36 of the ECM connector J2/P2.
Inlet Manifold Heater Relay: The Caterpillar Inlet Manifold Heater, or Flammstart is an option available for cold and high altitude applications. A heater plug in the inlet manifold preheats the engine and during cranking diesel fuel is directed onto the heater plug which mixes with air and ignites. The air is now heated before entering the inlet manifold. The fuel is tuned off after a predetermined duration expires.
Integrated Electronic Controls: The engine is designed with the electronic controls as a necessary part of the system. The engine will not operate without the electronic controls.
Logged Diagnostic Codes: Describes codes which are stored in memory. They are meant to be an indicator of possible causes for intermittent problems. Refer to Diagnostic Fault Code.
Oil Pressure Sensor: The ECM monitors oil pressure with a sensor located in the oil gallery. The ECM monitors oil pressure following engine start and can measure oil pressure from 0 kPa (o psi) to 690 kPa (100 psi). The sensor operates on +5 VDC supplied through pin-36 of the ECM connector J2/P2.
Open Circuit: Condition where an electrical wire or connection is broken or a switch is open, so that the signal or the supply voltage can no longer action its intended destination.
Original Equipment Manufacturer (OEM): As used here, the customer or manufacturer of a unit in which a Caterpillar engine is installed.
Parameter: A programmable value or limit which determines the characteristics or behavior of the engine and/or machine.
Passive Speed Sensor: A speed sensor not requiring a power and ground connection. It produces a signal based on the change in magnetic flux of a ferrous metal gear near the sensing tip.
Password: A group of numeric or alphanumeric characters, designed to restrict access to parameters. The electronic system requires correct passwords in order to change certain engine specifications (Factory Passwords). Passwords are also required to clear certain diagnostic codes.
Personality Module or Ratings Personality Module: The module inside of the ECM which contains all the instructions (software) for the ECM and performance maps for a specific power family.
Pulse Width Modulation (PWM): A signal consisting of variable width pulses at fixed intervals, whose ratio of "TIME ON" versus total "TIME OFF" can be varied (also referred to as "duty cycle").

Example of Pulse Width Modulation (PWM) Signals
Rated Fuel Position: ("Rated Fuel Pos" on ECAP) this indicates the maximum allowable fuel position (longest injection pulse). It will produce rated power for this engine configuration.
Reference Voltage: A regulated, unchanging voltage supplied by the ECM to a sensor. The reference voltage is used by the sensor to generate a signal voltage.
Remote Station Operation: Engine speed control from a location outside of the vessel cab, typically for some type of PTO operation for pumping or other application using engine power.
Sensor: A device used to detect and convert a change in pressure, temperature, or mechanical movement into an electrical signal.
Service Program Module (SPM): A software program on a factory programmable computer chip, designed to adapt an Electronic Service Tool to a specific application.
Short Circuit: A condition where an electrical circuit is unintentionally connected to an undesirable point. Example: a wire which rubs against a vessel frame until it wears off its insulation and makes electrical contact with the frame.
Signal: A voltage or waveform used to transmit information typically from a sensor to the ECM.
Speed/Timing Sensor: Provides a Pulse Width Modulated Signal to the ECM, which the ECM interprets as crankshaft position, direction of rotation and engine rpm and sends the signal to ECM.
Standard SAE Diagnostic Communications Data Link: Refer to CAT Data Link.
Subsystem: As used here, it is a part of the Electronic System that relates to a particular function, for instance throttle subsystem, etc.
Supply Voltage: A constant voltage supplied to a component to provide electrical power for its operation. It may be generated by the ECM, or it may be vessel battery voltage supplied by the vessel wiring.
System Configuration Parameters: Parameters which affect power rating family or emissions.
Tachometer: The Tachometer consists of the Tachometer connected to the ECM by connector P1/J1 and associated wiring. The ECM engine speed signal is provided by the Engine Speed/Timing Sensor into engine speed scaled at customer programmed pulses per revolution (ppr) before sending out to the Tachometer. The selection of the ppr for the Tachometer is done through a Customer Programmable Parameter, Tachometer Calibration.
NOTE: The ECM tachometer signal is set to 113 pulses per revolution at the factory. All tachometers driven from the ECM must be between 12 and 500 ppr. The most likely source of a tachometer problem is the wiring, then the tachometer itself and least likely the ECM. Do not disturb the Engine Speed/Timing Sensor to troubleshoot a tachometer problem.
Throttle Position: The ECM interpretation of the signal from the Throttle Position Sensor.
Throttle Position Sensor: An electronic sensor which is connected to an accelerator pedal or a hand lever and sends a Pulse Width Modulated Signal to the ECM.
Timing Calibration: The adjustment of an electrical signal as a means of correcting timing error between the crankshaft and camshaft. Refer to Speed/Timing Sensor.
Top Center (TC): The 180 degrees of crankshaft rotation before the piston reaches the very top of its travel (normal direction of rotation).
Torque Limit: Programmable parameter which limits the maximum torque based on PTO Configuration and operation.
Total Tattletale: Total number of changes to all Customer Specified Parameters stored in the ECM.
Transducer: A device which converts a mechanical signal to an electrical signal. Requires an external power source to operate.
Warning Lamp: Used to warn the operator of the presence of a Caterpillar Engine Monitoring detected problem.