ENGINE AR 7E0147 - Caterpillar

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Engine mounted ECM junction box
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ECMThe electronic control system is integrally designed into the engines fuel system, the engines air inlet, exhaust system in order to electronically control the fuel delivery, 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 precisely controlling the injector firing time. Engine rpm is controlled by adjusting the injection duration. The Electronic Control Module (ECM) energizes the unit injector solenoids in order to start the injection of fuel. Also, the ECM de-energizes the unit injector solenoids in order to stop the injection of fuel.The ECM has one 70-pin connector and one 120-pin connector.The flash file is used by the ECM to store all the rated information for a particular application. The flash file cannot be replaced physically. The flash file must be flash programmed with a PC.The engine uses the following three types of electronic components:
Input
Control
OutputAn input component sends an electrical signal to the ECM. The signal varies in one of the following ways:
Voltage
Frequency
Pulse widthThe variation of the signal is in response to a change in some specific part of the system. A specific example of an input component is the engine speed-timing sensor. The ECM interprets the signal from the input component as information about the condition, environment, or operation of the engine.A control module receives the input signals from an input device. Electronic circuits inside the control component evaluate the signals from the input components. These electronic circuits also supply an electrical signal to the output components of the system. The electrical signal that is supplied to the output components is based on predetermined combinations of input signal values.An output component is operated by a control module. The output component receives electrical signal from the control group. The output component uses that electrical signal in one of two ways. The output component can use that electrical signal in order to control. The output component can use that electrical signal for monitoring.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, an alarm will provide information to the operator of the engine.These electronic components provide the ability to electronically control the engine operation. Engines with electronic controls offer the following advantages:
Improvement in performance
Improvement in fuel consumption
Reduction in emissions levels