SCREW 3C8634 - Caterpillar

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Left side view (Typical example) (1) Inlet manifold pressure sensor (2) Inlet air temperature sensor (3) Electronic control module (ECM) (4) Secondary speed/timing sensor (5) Atmospheric pressure sensor (6) Engine oil pressure sensor
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Front view (Typical example) (7) Engine coolant temperature sensor (8) Primary speed/timing sensor
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Top view (Typical example) (9) Fuel pressure sensor (10) Fuel temperature sensor
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Left side view (Typical example) (11) Coolant level sensorThe electronic control system is integrally designed into the engine's fuel system and the engine's air inlet and exhaust system in order to electronically control the fuel delivery and the injection timing. The electronic control system provides increased timing control and fuel air ratio control in comparison to conventional mechanical engines. Injection timing is achieved by precise control of injector firing time, and engine rpm is controlled by adjusting the firing duration. The Electronic Control Module (ECM) energizes the solenoid in the unit injector in order to start the injection of fuel. Also, the ECM de-energizes the unit injector solenoids in order to stop injection of fuel. Refer to the Systems Operation, "Fuel System" topic for a complete explanation of the fuel injection process.The engine uses the following types of electronic components:
Inputs
Controls
OutputsAn input component is one that sends an electrical signal to the ECM. The signal that is sent varies in one of the following ways:
Voltage
Frequency
Pulse widthThe variation of the signal is in response to a change in some specific system of the unit. The ECM sees the input sensor signal as information about the condition, environment, or operation of the unit.A control component (ECM) receives the input signals. Electronic circuits inside the control component evaluate the signals from the input components. These electronic circuits also supply electrical energy to the output components of the system. The electrical energy that is supplied to the output components is based on predetermined combinations of input signal values.An output component is one that is operated by a control module. The output component receives electrical energy from the control component. The output component uses that electrical energy in one of two ways. The output component can use that electrical energy in order to perform work. The output component can use that electrical energy in order to provide information.