How to deal with EMI in automobile wiring harness

With the continuous development of automotive electronic control technology, the number of automotive electronic equipment has increased greatly, the working frequency has increased gradually, and the power has increased gradually, which makes the automotive working environment full of electromagnetic waves, leading to the increasingly prominent problem of electromagnetic interference, which affects the normal work of electronic equipment, and damages the corresponding electrical components. Therefore, more and more attention has been paid to the electromagnetic compatibility performance of automotive electronic equipment. At present, it is urgent to widely apply electromagnetic improvement technology for automotive electronic equipment.

The complexity and variability of the electromagnetic energy composition in the environment means that the system is subject to a wide range of sources of electromagnetic interference. Wire harness is the main source of electromagnetic interference in automobiles, and it is often subject to electromagnetic interference. So how to deal with electromagnetic interference is particularly important.

The following measures must be taken when dealing with EMI in automobile wiring harness:

1. Shielding interference source equipment and related wiring harness: The main electronic control unit used in automobile electronic control system should be encapsulated by shielding shell.

2. Increase wiring filter: For longer wiring harness, in order to reduce the interference of conduction and radiation, we should increase the filter on the wiring harness. It is more convenient to connect appropriate ferrite magnetic rings.

3. Reasonable planning of wiring harness: the arrangement of wiring harness makes the small power sensitive circuit close to the signal source, the high power interference circuit close to the load, and separates the small power circuit and the high power circuit as far as possible, so as to reduce the induction interference and radiation interference between wiring harnesses.

4. Improving the grounding of equipment: Good grounding arrangement and improved grounding overlap can reduce high-frequency impedance. The grounding of automotive electronic equipment is mainly connected to the car body and the shielding layer of the harness.

5. Reduce the area of interference received by the wire harness: the wire harness should be designed as the smallest length, the smallest impedance, and the smallest Ring Road area. It is better to use the power supply mode with small loop area such as a twisted pair. Increase the distance between the equipment and the interference source: In the case of the same arrangement of the interference equipment, the installation position of the sensitive components should be modified to increase the distance to the interference source.

In addition, the electromagnetic interference to the automobile system also comes from the outside of the car and the car body. The outside interference is the interference that the car is subjected to when it experiences various external electromagnetic environments while driving, and the static interference of the car body is related to both the automobile and the external environment. These two kinds of electromagnetic interference occur frequently in the daily operation of automobiles, which deserves our attention. The complexity and variability of the electromagnetic energy composition in the environment means that the system is subject to a wide range of sources of electromagnetic interference. Wire harness is the main source of electromagnetic interference in automobiles, and it is often subject to electromagnetic interference. So how to deal with electromagnetic interference is particularly important.