The engine is designed for electronic control. The engine has an Electronic Control Module (ECM), a fuel injection pump and electronic unit injectors. All of these items are electronically controlled. There are also a number of engine sensors. The engine has an electronically controlled wastegate for the turbocharger. The ECM controls the engine operating parameters through the software within the ECM and the inputs from the various sensors. The software contains parameters that control the engine operation. The parameters include all of the operating maps and customer-selected parameters.
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| Illustration 1 | g03461497 |
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Typical example of the control system layout for the engine with a single turbocharger (1) Air cleaner (2) Air inlet temperature sensor (3) Turbocharger outlet temperature sensor (4) Exhaust gas cooler (NRS) (5) Turbocharger (6) NRS temperature sensor (7) Exhaust gas valve for the NOx Reduction System (NRS) (8) NRS inlet pressure sensor (9) ATAAC outlet temperature sensor (optional) (10) Exhaust gas valve (NRS) (11) Air-to-air aftercooler (12) Wastegate regulator (13) NRS differential pressure sensor (14) Engine (15) Coolant temperature sensor (16) Crankshaft speed/timing sensor (17) Electronic unit injectors (18) Return fuel cooler (19) Camshaft speed/timing sensor (20) Fuel injection pump and fuel temperature sensor (21) Fuel pressure sensor (22) Oil pressure sensor (23) Atmospheric pressure sensor (24) ECM (25) Secondary fuel filter air purge restrictor (26) Fuel transfer pump (27) Primary fuel filter (28) In-line fuel filter (29) Boost pressure sensor (30) Inlet manifold air temperature sensor (31) Transfer pump inlet regulator (32) Secondary fuel filter (33) Fuel tank | |
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| Illustration 2 | g03461498 |
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Typical example of the control system layout for the engine with series turbochargers (1) Air cleaner (2) Air inlet temperature sensor (3) Turbocharger outlet temperature sensor (4) Low-pressure turbocharger (5) Exhaust gas cooler (NRS) (6) High-pressure turbocharger (7) NRS temperature sensor (8) Exhaust gas valve for the NOx Reduction System (NRS) (9) NRS inlet pressure sensor (10) ATAAC outlet temperature sensor (optional) (11) Exhaust gas valve (NRS) (12) Air-to-air aftercooler (13) Wastegate regulator (14) NRS differential pressure sensor (15) Engine (16) Coolant temperature sensor (17) Crankshaft speed/timing sensor (18) Electronic unit injectors (19) Return fuel cooler (20) Camshaft speed/timing sensor (21) Fuel injection pump and fuel temperature sensor (22) Fuel pressure sensor (23) Oil pressure sensor (24) Atmospheric pressure sensor (25) ECM (26) Secondary fuel filter air purge restrictor (27) Fuel transfer pump (28) Primary fuel filter (29) In-line fuel filter (30) Boost pressure sensor (31) Inlet manifold air temperature sensor (32) Transfer pump inlet regulator (33) Secondary fuel filter (34) Fuel tank | |
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| Illustration 3 | g03461499 |
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Block diagram for the aftertreatment system (33) Diesel Exhaust Fluid (DEF) level sensor (34) DEF temperature sensor (35) Coolant diverter valve (36) Main power relay Module (VLPM) (37) Voltage Load Protection (38) DEF header unit (39) Line heater relay (40) DEF tank (41) Dosing Control Unit (DCU) (42) Soot sensor and antennas (43) Heated DEF line (44) Heated DEF line (45) Diesel Particulate Filter (DPF) inlet temperature sensor (46) DPF outlet NOx sensor (47) Exhaust Back Pressure Regulator (EBPR) (48) Diesel Oxidation Catalyst (DOC) (49) Diesel Particulate Filter (DPF) (50) DEF filter (51) Heated DEF line (52) DEF injector (53) DEF dosing pump (54) Selective Catalytic Reduction (SCR) catalyst (55) Ammonia Oxidizing (AMOX) catalyst (56) SCR inlet temperature sensor (57) SCR outlet NOx sensor (58) Identification module | |
The electronic control system has the following components:
- ECM
- Pressure sensors
- Temperature sensors
- Crankshaft speed/timing sensor
- Camshaft speed/timing sensor
- The suction control valve for the fuel injection pump
- Wastegate regulator
- Electronic unit injectors
- Soot sensors
- Valve for the NOx Reduction System (NRS)
Sensor Locations for the Engine
The illustrations in this section show the typical locations of the sensors for the industrial engine. Specific engines may appear different from the illustration due to differences in applications.
Note: In the following illustrations, some components have been removed in order to improve visibility.
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| Illustration 4 | g03056096 |
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Typical example of the sensor locations on the left side of the engine (1) Coolant temperature sensor (2) Fuel temperature sensor (3) Suction control valve for the fuel injection pump (4) Inlet manifold temperature sensor (5) Boost pressure sensor (6) Fuel pressure sensor (7) Electronic Control Module (ECM) (8) Atmospheric pressure sensor (9) Crankshaft speed/timing sensor (10) Oil pressure sensor (11) Oil level switch (if equipped) | |
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| Illustration 5 | g03056576 |
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Typical example of the close up views of sensor locations on the left side of the engine (1) Coolant temperature sensor (2) Fuel temperature sensor (3) Suction control valve for the fuel injection pump (4) Inlet manifold temperature sensor (5) Boost pressure sensor (6) Fuel pressure sensor (7) Electronic Control Module (ECM) (8) Atmospheric pressure sensor (9) Crankshaft speed/timing sensor (10) Oil pressure sensor (11) Oil level switch (if equipped) | |
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| Illustration 6 | g03058197 |
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Typical example of the sensor locations on the right side and top of the engine (12) NOx Reduction System (NRS) differential pressure sensor (13) NRS inlet pressure sensor (14) NRS inlet temperature sensor (15) NRS valve including a position sensor (16) Wastegate regulator (17) Camshaft speed/timing sensor (18) Exhaust Back Pressure Regulator (EBPR) | |
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| Illustration 7 | g03058278 |
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Typical example of close up views of sensor locations on the top of the engine (12) NOx Reduction System (NRS) differential pressure sensor (13) NRS inlet pressure sensor (14) NRS inlet temperature sensor (15) NRS valve including a position sensor (16) Wastegate regulator | |
Sensor Locations for the Clean Emissions Module
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| Illustration 8 | g03058296 |
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Typical example of the sensors and components on the Clean Emissions Module (CEM) (19) Diesel Particulate Filter (DPF) outlet NOx sensor (20) Soot sensor antenna (21) Intake temperature sensor for the Selective Catalytic Reduction (SCR) system (22) Aftertreatment ID module (23) Temperature sensor electronics module (24) Diesel Exhaust Fluid (DEF) injector | |
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| Illustration 9 | g01926054 |
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Typical example | |
The Electronic Control Module (ECM) (1) controls various engine systems and acts as a computer for the engine.
The electronic system consists of the ECM, the engine sensors, and inputs from the parent machine. The ECM is the computer. The flash file is the software for the computer. The flash file contains the operating maps. The operating maps define the following characteristics of the engine:
- Engine rating
- Torque curves
- High and low idle speed (rpm)
- Emissions
- Injection timing
The factory passwords restrict changes to authorized personnel. Factory passwords may be required to clear any event code depending on the security level of the event code. Refer to Troubleshooting, "Factory Passwords" for more information on the passwords.
The ECM has an excellent record of reliability. Any problems in the system are most likely to be the connectors and the wiring harness. The ECM should be the last item in troubleshooting the engine.
The programmable software contains all the fuel setting information. The information determines the engine performance.
Flash programming is the method of programming or updating the programmable software. Refer to Troubleshooting, "Flash Programming" for the instructions on the flash programming of the programmable software.
The ECM is sealed and the ECM needs no routine adjustment or maintenance.
The electronic controls determine the injection timing, the amount of fuel that is delivered to the cylinders and the intake manifold pressure via the electronically controlled wastegate. These decisions are based on the actual conditions and the desired conditions at any given time.
This is also dependant upon the state of the SCR system, the DEF system, the level of soot in the DPF, the temperature of the aftertreatment system, and other parameters.
The ECM has software that compares the desired engine speed to the actual engine speed. The actual engine speed is determined through the crankshaft speed/timing sensor and the camshaft speed/timing sensor. If the desired engine speed is greater than the actual engine speed, the ECM will instruct the electronic unit injector to inject more fuel in order to increase engine speed.
Once the ECM has determined the amount of fuel that is required, the software must determine the timing of the fuel injection. Fuel injection timing is determined by the ECM after considering input from the following components:
- Engine coolant temperature sensor
- The sensor for the inlet manifold temperature
- The sensor for the boost pressure
- The rate of flow in the NOx Reduction System (NRS)
- The amount of Nitrogen Oxide (NOx) that is produced by the engine
- The temperature of the aftertreatment
- The soot level
At start-up, the ECM determines the top center position of the number 1 cylinder from the secondary speed/timing sensor on the camshaft. The ECM decides when fuel injection should occur relative to the top center position. The ECM optimizes engine performance by control of each of the electronic unit injectors so that the required amount of fuel is injected at the precise point of the engine's cycle. The electronic unit injectors are supplied high-pressure fuel from the fuel manifold. The ECM also provides the signal to the solenoid in the fuel injection pump. The solenoid in the fuel injection pump controls a valve in the fuel injection pump. This valve controls the volume of fuel that enters the plungers. By controlling the volume of fuel that enters the plungers, this controls the pressure in the fuel manifold. Fuel that is not required for the engine is diverted away from the fuel injection pump back to the fuel tank.
The ECM adjusts injection timing and fuel pressure for the best engine performance, the best fuel economy, and the best control of exhaust emissions. The actual timing can be viewed with an electronic service tool. Also, the desired timing can be viewed with an electronic service tool.
The programmable software inside the ECM sets certain limits on the amount of fuel that can be injected.
The FRC Limit is a limit that is based on intake manifold air pressure and engine rpm. The FRC Limit is used to control the air/fuel ratio in order to control the engine's exhaust emissions. When the ECM senses a higher intake manifold air pressure, the ECM increases the FRC Limit. A higher intake manifold air pressure indicates that there is more air in the cylinder. When the ECM increases the FRC Limit, the ECM allows more fuel into the cylinder.
The Rated Fuel Limit is a limit that is based on the power rating of the engine and on the engine rpm. The Rated Fuel Limit enables the engine power and torque outputs to conform to the power and torque curves of a specific engine model.
These limits are in the programmable software and these limits cannot be changed.
The ECM controls the following characteristics:
- Boost pressure
- Operation of the NOx reduction system (NRS)
- Selective Catalytic Reduction (SCR)
- Diesel Exhaust Fluid (DEF) system
When the ECM detects an electronic system problem, the ECM generates a diagnostic code. The ECM logs the diagnostic code. The ECM records the hours of engine operation that the diagnostic code has occurred. The ECM also logs the number of occurrences of the problem. Diagnostic codes are provided in order to indicate that the ECM has detected an electrical problem or an electronic problem with the engine control system. In some cases, the engine performance can be affected when the condition that is causing the code exists.
If the operator indicates that a performance problem occurs, the diagnostic code may indicate the cause of the problem. Use a laptop computer to access the diagnostic codes. The problem should then be corrected.
Event Codes are used to indicate that the ECM has detected an abnormal engine operating condition. The ECM will log the occurrence of the event code. This does not indicate an electrical malfunction or an electronic malfunction. For example, if the temperature of the coolant in the engine is higher than the permitted limit, then the ECM will detect the condition. The ECM will then log an event code for the condition.
System Configuration Parameters are protected by factory passwords. This will prevent unauthorized reprogramming of the system and the unauthorized removal of logged events. Factory passwords are calculated on a computer system that is available only to Caterpillar dealers. Since factory passwords contain alpha-numeric characters, only an electronic service tool may change System Configuration Parameters. System Configuration Parameters affect the power rating or the emissions. Passwords also allow the customer to control certain programmable engine parameters.
Refer to Troubleshooting, "Programming Parameters" and Troubleshooting, "Factory Passwords".
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| Illustration 10 | g01926057 |
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Typical example | |
The primary speed/timing sensor is located on the left-hand side of the cylinder block close to the flywheel housing. The primary speed/timing sensor generates a signal by detecting the movement of the teeth that are located on the crankshaft timing ring (1). 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 signal is also used to determine the engine speed.
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| Illustration 11 | g03330221 |
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Typical example | |
The secondary speed/timing sensor is located on the right-hand side of the cylinder block toward the rear of the engine. 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 (2) 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.
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| Illustration 12 | g03167336 |
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Schematic for speed/timing sensor | |
The secondary speed/timing sensor is required for starting purposes.
During normal operation, the secondary speed/timing sensor is used to determine the cycle that the engine is on. When the timing has been established, the primary speed/timing sensor is then used to determine the engine speed and the angular position.
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| Illustration 13 | g03167376 |
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Schematic for the pressure sensors | |
The engine pressure sensors are active sensors.
For example, the boost pressure sensor provides the ECM with a measurement of inlet manifold pressure in order to control the air/fuel ratio. This will reduce the engine smoke during transient conditions.
The operating range of the boost pressure sensors is
For example, the engine oil pressure sensor provides the ECM with a measurement of engine oil pressure. The ECM can warn the operator of possible conditions that can damage the engine. This includes the detection of an oil filter that is blocked.
The operating range for the engine oil pressure sensor ...
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| Illustration 14 | g03167476 |
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Schematic for the engine temperature sensors | |
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| Illustration 15 | g03167356 |
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Schematic for the temperature sensors for the engine aftertreatment system | |
The temperature sensors are passive sensors. Each sensor provides a temperature input to the ECM. The ECM controls following operations:
- Fuel delivery
- Injection timing
- Air inlet and exhaust system
- Operation of the NOx reduction system (NRS)
- Selective Catalytic Reduction (SCR)
The operating range for the sensors ...
The operating range for the fuel temperature sensor ...
The sensors are also used for engine monitoring.
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| Illustration 16 | g03167338 |
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A typical example of a schematic of the position sensors | |