Actual Rack - The actual rack is the Electronic Control Module's interpretation of the signal from the rack position sensor.
Actual Timing Advance - The actual timing advance is the number of degrees of timing advance beyond static timing. The actual timing advance is measured by the timing position sensor.
After Market Device - An after market device is a device or an accessory that is installed by the customer after the vehicle is delivered.
Air-To-Air Aftercooler - An air-to-air aftercooler is a device that is used on turbocharged engines in order to cool inlet air that has undergone compression. The inlet air is cooled after the inlet air passes through the turbocharger. The inlet air is passed through an aftercooler (heat exchanger) that uses ambient air for cooling. The inlet air that has been cooled advances to the inlet manifold.
Alternating Current (AC) - The direction of the current flow changes. The current flow alternates constantly.
American Wire Gauge (AWG) - AWG is a measure of the diameter of electrical wire. AWG is also a measure of the current carrying capacity of electrical wire. When the AWG number is smaller, the diameter of the wire is larger. When the AWG number is larger, the diameter of the wire is smaller.
Atmospheric Pressure Sensor - The atmospheric pressure sensor measures barometric pressure. The sensor sends a signal to the electronic control module (ECM). The signal is used in engine control and in engine operation.
Before Top Center (BTC) - Before Top Center is the 180 degrees of crankshaft rotation before the piston reaches the top center position in the normal direction of rotation.
Boost Pressure Sensor - The boost pressure sensor measures inlet manifold air pressure. The boost pressure sensor sends a signal to the Electronic Control Module (ECM).
Brushless Torque Motor (BTM) - A Brushless Torque Motor (BTM) is a solenoid that is used in order to move the fuel rack servo spool valve and the timing advance spool valve.
Bypass Circuit - A bypass circuit is a circuit that is used as a substitute circuit for an existing circuit. A bypass circuit is typically used as a test circuit.
Calibration - Calibration is an electronic adjustment.
Code - See the Diagnostic Code.
Cruise Control Range - The cruise control range establishes the vehicle speed range for the operation of cruise control. The range is usually limited to the speed range that is anticipated on the open road.
Customer Specified Parameters - A customer specified parameter is a parameter that can be changed. A customer specified parameter's value is set by the customer. These parameters are protected by customer passwords.
Dash Check Engine Lamp - The dash check engine lamp is sometimes called the diagnostic lamp. The dash check engine lamp is used to warn the operator of the presence of an active diagnostic code.
Desired Rack Position - This is the rack position that is calculated by the electronic control module (ECM) in order to attain the desired rpm. The desired rack position is also used to maintain the desired RPM.
Desired RPM - The desired rpm is input to the electronic governor within the ECM. The electronic governor uses the signal from the Accelerator Pedal Position Sensor, the Engine Speed Sensor, the Cruise Control, and the Customer Parameters in order to determine desired rpm.
Desired Timing Advance - This is the fuel injection timing advance that is calculated by the electronic control module (ECM) in order to meet emissions and performance specifications.
Diagnostic Code - A diagnostic code is sometimes called a fault code. A diagnostic code is an indication of a problem or event in the electrical engine systems.
Diagnostic Lamp - A diagnostic lamp is sometimes called the check engine light. The diagnostic lamp is used to warn the operator of the presence of an active diagnostic code.
Digital Diagnostic Tool (DDT) - This is a Caterpillar tool that is used to program the 3406C PEEC III system. The digital diagnostic tool can be used to diagnose the 3406C PEEC III system.
Direct Current (DC) - Direct current is the type of current that flows consistently in only one direction.
Duty Cycle - See Pulse Width Modulation.
Electronic Control Analyzer Programmer (ECAP) - The ECAP is a Caterpillar electronic service tool. The ECAP is used for programming and for diagnosing various types of electronic controls.
Electronic Control Module (ECM) - The ECM is the engine's control computer. The ECM provides power to the electronics. The ECM monitors data that is input from the engine's sensors. The ECM acts as a governor in order to control engine rpm.
Engine Speed/Timing Sensor - The engine speed/timing sensor provides a pulse width modulated signal to the ECM. The ECM interprets the signal as the crankshaft position and the engine speed.
Estimated Dynamic Timing - Estimated dynamic timing is the electronic control module's calculation of the actual injection timing.
Failure Mode Identifier (FMI) - The FMI describes the type of failure that was experienced by the component. The codes for the FMI were adopted from the standard practices of SAE (J1587 diagnostics).
Fuel Ratio Control (FRC) - The FRC is a limit that is based on the control of the fuel to air ratio. The FRC is used for emission control. When the ECM senses a higher turbocharger outlet pressure, the ECM increases the limit for the FRC in order to allow more fuel into the cylinders.
Fuel Off - Fuel off refers to the minimum fuel position of the fuel rack.
Fuel On - Fuel on refers to the maximum fuel position of the fuel rack.
Harness - The harness is the bundle of wiring that connects all the components of the electrical engine system.
Hertz (Hz) - Hz is the measure of frequency in cycles per second.
Oil Pressure Sensor - The oil pressure sensor measures engine oil pressure and the oil pressure sensor sends a signal to the ECM as part of Caterpillar Engine Monitoring.
Open Circuit - An open circuit is a broken electrical wire connection. The signal or the supply voltage cannot reach the intended destination.
Original Equipment Manufacturer (OEM) - An OEM is the manufacturer of a vehicle that utilizes a Caterpillar engine.
Parameter - A parameter is a programmable value which affects the characteristics or the behavior of the engine and/or vehicle.
Password - A password is a group of numeric characters or alphanumeric characters. A password is designed to restrict the changing of information in the ECM. The electrical engine systems require correct customer passwords in order to change customer specified parameters. The electrical engine systems require correct factory passwords in order to clear certain logged events. Factory passwords are also required in order to change certain engine specifications.
Personality Module - The personality module is the module in the ECM which contains all the instructions (software) for the ECM and performance maps for a specific horsepower family. Updates and rerates are accomplished by electronically flashing in new data. The updates and rerates are flashed in using an electronic service tool.
Power Take-Off (PTO) - The power take-off is operated with the cruise control switches or with the dedicated PTO switches. This mode of operation permits setting constant engine rpm when the vehicle is not moving or when the vehicle is moving at slow speeds.
Programmable Electronic Engine Control (PEEC III) - Programmable Electronic Engine Control (PEEC III) is the complete electronic system that monitors the engine operation under all conditions. Programmable Electronic Engine Control (PEEC III) controls the engine operation under all conditions.
Progressive Shifting - Progressive shifting is the preferred method of shifting through the lower gears. Shifts are made before max rpm is reached in each gear. Shifts are made above the peak torque but below rated rpm. Needlessly winding up the engine into the higher rpm ranges before shifting to the next gear wastes fuel. Needlessly winding up the engine into the higher rpm ranges before shifting to the next gear fails to take advantage of the torque rise of the engine.
Pulse Width Modulation (PWM) - A PWM is a digital type of electronic signal that corresponds to a measured variable. The length of the pulse (signal) is controlled by the measured variable. The variable is quantified by a certain ratio. This ratio is the percent of "on-time" that is divided by the percent of "off-time". A PWM signal is generated by the Throttle Position Sensor.
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| Illustration 1 | g00518072 |
Examples of Pulse Width Modulation Signals | |
Rated Rack Position - This is the limit on the rack position which provides the specified horsepower and torque curves. This value comes from maps that are programmed into the personality module at the factory.
Rack Position Sensor - The rack position sensor is a linear position sensor which follows the movement of the rack assembly. The sensor then sends an electrical signal to the electronic control module.
Rack Solenoid (BTM) - The rack solenoid is a rotary proportional solenoid (BTM) that is used to move the fuel rack servo spool valve.
Reference Voltage - The reference voltage is a regulated voltage that is used by the sensor in order to generate a signal voltage.
Sensor - A sensor is used to detect a change in the pressure, in the temperature, or in mechanical movement. When any of these changes are detected, a sensor converts the change into an electrical signal.
Service Program Module (SPM) - The SPM is a software program on a computer chip that was programmed at the factory. The computer chip is designed to adapt an ECAP for a particular application.
Short Circuit - A short circuit is an electrical circuit that is mistakenly connected to an undesirable point. For example, an electrical contact is made with the frame whenever an exposed wire rubs against a vehicle's frame.
Signal - A signal is a voltage or a wave that is used to transmit information that is typically from a sensor to the ECM.
Speed Burp - A speed burp is a sudden brief change in engine rpm.
Static Timing Specification - This is the fixed number of degrees that are determined by design of the fuel pump camshaft. The value that is displayed is the specification for static timing. The value is not an electrically measured value.
Subsystem - A subsystem is a part of the engine system that relates to a particular function.
Supply Voltage - Supply voltage is a constant voltage that is supplied to a component in order to provide electrical power for operation. Supply voltage may be generated by the ECM. Supply voltage may also be the battery voltage of the vehicle that is supplied by the vehicle wiring.
"T" Harness - This harness is a test harness that is designed to permit normal circuit operation and the measurement of the voltage simultaneously. Typically, the harness is inserted between the two ends of a connector.
Throttle Position - The throttle position is interpreted by the ECM. The accelerator pedal position sensor sends the ECM signals. The throttle position may be used as part of a power take-off control.
Throttle Position Sensor - The throttle position sensor is an electronic sensor that is connected to the throttle pedal. The throttle position sensor sends a pulse width modulated signal to the ECM.
Timing Position Sensor - This is a linear position sensor which follows movement of the timing advance unit. The sensor then sends an electrical signal to the ECM.
Timing Solenoid (BTM) - The timing solenoid is a rotary proportional solenoid (BTM) that is used to move the timing advance unit spool valve.
Total Tattletale - The total tattletale is the total number of changes to all system parameters.
Transducer - A transducer is a device that converts a mechanical signal to an electrical signal.
Transducer Module - This is a sealed unit that is mounted below the rack actuator housing. The transducer module contains the engine's oil pressure sensor, the boost pressure sensor, and the protective signal conditioning circuitry.
Vehicle Speed Buffer - The vehicle speed buffer is a device that is used to condition the output of the vehicle speed sensor. The vehicle speed buffer amplifies the output of the vehicle speed sensor.
Vehicle Speed Sensor - A vehicle speed sensor is an electromagnetic pickup that measures vehicle speed from the rotation of gear teeth in the drive train of the vehicle.