What are the advantages of using electronically controlled fuel injection system in gasoline engines?
(1) adopts electronically controlled fuel injection technology, which reduces the exhaust pollution and fuel consumption of the engine and can meet more stringent emission regulations.
(2) 2) The ECU responds quickly to the change of the throttle, which improves the handling performance and acceleration performance of the motorcycle and maintains a good dynamic performance index.
(3) Because the ECU system is very accurate, it reduces the knocking tendency of the engine, so it allows the engine to adopt a higher compression ratio, thus improving the thermal efficiency of the engine.
(4) It is easy to start, which is especially beneficial to the cold car starting in the low temperature environment in winter. The electronic control device controls the air-fuel ratio under different working conditions through computer programs, and abandons the carburetor choke starting device to make the cold car start more reliable.
(5) The performance of the engine can be adjusted conveniently, and the fuel quantity and ignition time of the engine under different working conditions can be set conveniently, so as to meet the requirements of the motorcycle on engine performance under various road conditions.
(6) EFI system has strong adaptability. For different types of engines, only by changing the "pulse diagram" in the ECU chip, the injector ECU of the same oil pump can be used in a variety of products with different specifications and models, and the EFI technology can be extended to other types of engines.
Composition of electronic control system of gasoline engine
There are many types and models of electronic control systems for modern automobile gasoline engines, but their structures and principles are similar. Like the electronic control of diesel fuel supply system, they are also divided into three parts: sensor, electronic controller (ECU) and actuator.
Various sensors and switches can timely and truly transmit the driver's intention, the working condition of gasoline engine and environmental information to the electronic controller.
According to the input signals from various sensors and other switch signals, the electronic controller uses control software to analyze and calculate with various stored calibration data and charts to decide how to control, and sends various control instructions to various actuators with corresponding electrical signals, and the actuators generate corresponding actions to realize the required control.
Among all sensor inputs, engine speed and air flow (or intake manifold absolute pressure) representing engine load are the two most basic inputs.
According to them, the electronic controller determines the basic values of ignition advance angle and fuel injection pulse width. Coolant temperature and intake air temperature are both conditional parameters used to correct the basic ignition advance angle and fuel injection pulse width.
The angular position signal of crankshaft (or camshaft) is used to determine the ignition time and injection time relative to the top dead center of each cylinder. The signal of throttle opening sensor is necessary for judging idle working condition and compensating fuel injection under transient working condition.
When a gasoline engine is equipped with a three-way catalytic converter, an oxygen sensor that can reflect the air-fuel ratio must be installed in front of the catalytic converter (one before and one after the catalytic converter) to input feedback signals for the closed-loop control of air-fuel ratio under partial load and hot idle conditions.
The deflagration intensity and frequency detected by the deflagration sensor are used as the basis for the electronic controller to decide to delay ignition to avoid deflagration. According to the specific conditions of the engine, other sensors (such as boost pressure, oil pressure, vehicle speed and battery voltage, etc. ) can be provided.
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