Briefly describe the classification of gasoline injection system?

The classification of gasoline injection system can be roughly divided into the following five categories;

A, according to the nozzle installation position points:

1) single-point injection type (centralized injection is installed on the throttle body)

2) Multi-point injection type (installed on the intake manifold of each cylinder to inject oil separately)

Second, according to the injection time classification:

1) continuous injection type: the fuel injector continuously injects fuel during the engine operation, and the injection amount depends on the mechanical (or electromechanical) fuel distributor.

2) Intermittent injection type: ECU controls the fuel injection quantity of fuel injectors to inject fuel intermittently during engine operation, including independent injection of each cylinder, simultaneous injection of each cylinder and grouped injection.

Three, according to the fuel injection quantity classification:

1) Mechanical (K-type) fuel injection quantity is controlled by spark plug metering box according to air intake.

2) In the electromechanical type (KE type), the fuel injection quantity is also controlled by the spark plug metering box according to the intake air quantity, but with the participation of ECU, the correction values of water temperature and throttle position are added.

3) Electronic (E-type) adopts ECU to directly control the fuel injection quantity, and is equipped with sensors and actuators. ECU calculates timely and appropriate fuel quantity and optimal ignition time. It can also control the idle state.

Four, according to the airflow classification:

1) mass flow type: directly measure air mass flow and calculate fuel injection quantity (K, KE, L, LH type).

2) Velocity density formula: According to the intake pipe pressure and engine speed, calculate the air intake and fuel injection (D type).

3) Throttle speed formula: According to the throttle opening and engine speed, calculate the air intake and fuel injection.

Five, according to the presence or absence of feedback signal classification

1) open-loop control: the actual output cannot be checked, but the structure is simple; Easy to implement.

2) Closed-loop control: use the feedback signal to adjust the input and make the output meet the requirements.