There are several types of electronically controlled ignition systems. What are their control objectives?

Three common ignition systems are introduced.

1, magnetic induction electronic ignition system

Cars such as Jiefang CA 1092, Dongfeng EQ 1092, Beijing BJ2020 and some cars produced in the early days are equipped with magnetic induction electronic ignition systems. It is mainly composed of magnetic induction distributor, ignition controller, high-energy ignition coil and spark plug. See the schematic diagram of magnetic induction electronic ignition system (figure 1).

The magnetic induction distributor is mainly composed of magnetic induction sensor, ignition advance adjustment device and distributor. The magnetic induction sensor consists of rotor, stator, permanent magnet and 1 turn induction wire. When the engine is working, the distributor passes through the rotor and stator, so that the magnetic flux in the coil of the sensor line 1 changes, and a voltage signal is generated and supplied to the ignition controller. Its outstanding advantages are simple structure and no need for external power supply. Automobile maintenance network

Ignition controller, also known as electronic ignition controller, electronic ignition assembly or igniter, is mainly composed of ignition ASIC and some auxiliary electronic components. Its main function is to control the turn-on and turn-off of the primary winding circuit of the ignition coil according to the voltage signal output by the magnetic induction sensor, so that the ignition coil generates high voltage. In addition, the ignition controller also has the functions of constant current control, closing angle control, power-off control and overvoltage protection.

2. Hall electronic ignition system

Hall electronic ignition system is used in most cars of Jiefang CA6440, Jiefang CA 1046 and some cars produced in the early stage. It is mainly composed of Hall distributor, ignition controller, high-energy ignition coil and spark plug. Refer to the circuit diagram of Hall electronic ignition system (Figure 2).

Hall distributor is mainly composed of Hall sensor, ignition advance regulator and distributor. Hall sensor consists of trigger impeller, Hall integrated circuit, magnetic conductive steel sheet, permanent magnet, etc. When the engine is working, the distributor changes the magnetic flux of Hall ic by triggering the impeller to generate a voltage signal, which is provided to the ignition controller. Unlike magnetic induction sensors, Hall sensors require an input voltage.

3, microcomputer control ignition system

In the electronic centralized control system of engine, the ignition system controlled by microcomputer is called microcomputer-controlled ignition system. Most cars produced now adopt microcomputer-controlled ignition systems. The ignition system is mainly composed of sensor, electronic controller, ignition controller (igniter), ignition coil and spark plug. Refer to the schematic diagram of microcomputer-controlled ignition system (Figure 3).

The sensor is a device to monitor the working state information of the engine. The structure and number of sensors vary from car to car, mainly including crankshaft position sensor, air flow sensor, throttle position sensor, knock sensor, cooling water temperature sensor, air temperature sensor, oxygen sensor, speed sensor, neutral start switch, ignition switch, air conditioning switch, battery, etc.

The electronic controller is represented by ECU. ECU is the control core of the engine. The names of electronic controllers are not uniform. Different manufacturers or companies have different names for different production years and control contents. Electronic controller mainly includes input loop, output loop, analog-to-digital A/D converter or analog-to-digital D/A converter, single chip microcomputer and power supply circuit. Because the core component of electronic controller is single chip microcomputer, electronic controller is usually called microcomputer or computer. The function of the electronic controller is to control the related actuators (such as igniter) to work according to the information input by the sensor of the engine and the stored data of the microcomputer, and then output the command signal.

The ignition controller is the executive mechanism of the engine control system, and its function is to control the on-off of the primary winding circuit of the ignition coil through the on-off of the internal high-power triode according to the instruction signal sent by the microcomputer, so that the ignition coil generates high-voltage electricity. The internal structure of igniters of various engines is different. Some engines are not equipped with igniter, and the high-power triode is directly installed in the electronic controller ECU. Some igniters only have a Darlington transistor, which only plays the role of switch, and other electronic control components are integrated with the electronic controller; Some igniters have the functions of constant current control, closing angle control, cylinder discrimination, ignition monitoring and so on.

In addition, the microcomputer-controlled ignition system can be divided into distributed ignition system (with distributor) and direct ignition system (without distributor). The high-voltage electricity generated by the ignition coil of distributed ignition system is distributed to the spark plugs of each cylinder by the distributor according to the working order of the engine, which still produces more electric sparks, which not only wastes energy, but also produces electromagnetic interference signals. However, there is no distributor in the direct ignition system, and both ends of the secondary winding of the ignition coil are directly connected with the spark plug. When the engine is running, the microcomputer directly controls each ignition coil to generate high voltage electricity according to the sensor signal to ignite the corresponding spark plug. So far, the distributor-free microcomputer-controlled ignition system is the most advanced technology.