PISTON 1338780 - Caterpillar

Illustration 1 g02318075
(1) Secondary speed/timing sensor
(2) Boost pressure sensor
(3) Fuel pressure sensor (secondary filter outlet)
(4) Fuel temperature sensor
(5) Fuel pressure sensor (secondary filter inlet)
(6) NRS intake pressure sensor
(7) NRS differential pressure sensor
(8) Coolant temperature sensor
(9) Primary speed/timing sensor
(10) Atmospheric pressure sensor
(11) Crankcase pressure sensor
(12) Inlet air temperature sensor
(13) Engine oil pressure sensor
(14) Electronic Control Module (ECM) The electronic control system is integrally designed into the fuel system and the air inlet and exhaust system in order to control the fuel delivery and the injection timing electronically. The electronic control system provides increased timing control and fuel air ratio control in comparison to conventional mechanical engines. The primary speed/timing sensor is a crankshaft position sensor and the secondary speed/timing sensor is a camshaft position sensor. 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 that is in the unit injector in order to start the injection of fuel. 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 engine. The electronic control module sees the input sensor signal as information about the condition, environment, or operation of the engine.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.
As an example, a moving solenoid plunger will perform work. By performing work, the component has functioned in order to regulate the engine.
As an example, a warning light or an alarm will provide information to the operator.