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VII. Engine Management System
EFI System Composition
The Engine Management System (EMS) is comprised of the following components: Electronic control unit (ECU), throttle body, Idle speed
control valve, fuel pump, fuel injector, ignition coil, O2 sensor, throttle position sensor, T-MAP sensor, cylinder head temperature sensor, etc.
The EMS uses sensors to collect parameters such as air flow, temperature of inlet air, cylinder head temperature, atmospheric pressure and
the operational state of engine (rpm, load, acceleration and deceleration). All parameters are transferred to the ECU via electronic signal. The
ECU outputs control signals after the input signals have been processed. Based on the air flow and engine speed, the fuel injector and ignition
coil are controlled by ECU to get the optimal combustible mixture of fuel and air and Ignition timing which meet all engine operating conditions.
Through the engine and actuator components on the
vehicle (ignition coil, fuel injector, idle speed control valve and so on), the fuel and spark are
precisely controlled and corrected with closed loop.
System composition:
1. Sensors:
•
Intake air pressure sensor (load information) intake air temperature and pressure sensors
• Throttle position sensor (load information, load range information, acceleration / deceleration information)
• Engine speed sensor (speed information, crankshaft position)
• Intake air temperature sensor (air density information)
• Oxygen sensor (information of the excess air coefficient is more than 1 or less than 1)
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