Selection of Automobile Wire Type

The interior of an automobile is a very complicated small environment, where there are various factors such as high temperature, cold, friction, vibration, organic solvents, inflammables and interference noise, etc. Automobile wire harnesses are also different from ordinary wiring harnesses and cables. According to the laying position and functional requirements, it is required that the wiring looms should have various performances such as heat resistance, cold resistance, oil resistance, wear resistance, flame retardance and interference resistance. Therefore, the line type of automobile wires should be reasonably selected according to the different environment and functions of the wires. For example, the ambient temperature around the engine in the front cabin is high, and there are many corrosive gases and liquids. Therefore, it is necessary to use high-temperature resistant, corrosion-resistant, oil-resistant, vibration-resistant and friction-resistant wires. Generally, the temperature resistance of the wires in the front cabin of automobiles is required to be between -40 and 125℃; However, the environment of the cab is relatively comfortable, and the temperature resistance of the used automobile wires between -40 and 85℃ can meet the requirements. In addition, according to the different functions, the wire selection of different electrical systems of automobiles is also different.

1 Common Wires for Automobiles

1.1 GB Wire

National standards (QVR, etc.) are mainly used for trucks, buses and special vehicles. It is characterized by thick insulation, softness and good ductility.

1.2 Japanese Standard wire

Japanese standard wires (AVSS, etc.) are mainly used for Japanese cars and some domestic independent brand cars. Japanese standard wire is characterized by thin skin insulation and good flexibility.

1.3 German standard Wire

German standard electric wires (FLRY-B, etc.) are widely used, mainly for German cars, American cars, some domestic independent brand cars and special vehicles. German standard wire is characterized by thinner insulation and good flexibility.

1.4 American Standard Wire

American standard wires (TXL, etc.) are seldom used in China, and are mainly used for American models. American standard wire is characterized by thin skin insulation and excellent heat resistance.

1.5 Special Wires

Special electric wires for automobiles mainly include stranded wire, shielded wire, ABS cable, radio antenna, video cable, GPS antenna, fusible wire, braided wire, etc. According to the different vehicle types and electrical functions, these special wires are applied in the corresponding electrical systems to realize their respective special functions. Stranded wire is generally made up of two single wires twisted according to a certain twist pitch. It can resist external interference by using its own twist, which has a certain anti-interference effect. Shielding wires are commonly used in single-core shielded wires and double-core shielded wires. According to the different shielding layers, they are divided into mesh shielded wires and aluminum foil shielded wires. Shielding wires use metal materials (shielding wires) to separate the interference source from the disturbed wires, so as to reduce the interference electromagnetic field. They have a good shielding effect, and their anti-interference ability is better than that of stranded wires. ABS cable is generally a two-core cable, which is characterized by good wear resistance, high strength, softness and bending resistance. The radio antenna, video cable and GPS antenna are special shielded cables with good anti-interference and signal transmission capabilities. The application of fusible link is gradually decreasing, and its function is equivalent to fusible link, which is used to protect the circuit. Braided wire is mainly used for grounding connection of Wire Harness, which has good signal shielding effect.

2 Selection of Special Wires in Main Electrical Systems

2.1 Engine ECU Control System

Engine ECU is called the on-board computer of automobile, and it is one of the core components of automobile electrical appliances. Its working voltage range is generally 6.5~16V, and its working current is 0.015~0.1A. Most sensors are weak signals, and they are in the environment of vibration, high temperature, high pressure and corrosive dust in the front cabin. Therefore, in order to ensure the correct transmission of weak signals and prevent electromagnetic interference, shielded wire or stranded wire must be selected when selecting the functions of knock sensor, crankshaft sensor, camshaft sensor, electronic accelerator pedal, front oxygen sensor and rear oxygen sensor.

2.2ABS anti-lock braking system

ABS (Anti-lock Braking System), as one of the important signs of automobile active safety, has been widely used in modern automobiles. As the "scout" of the ABS system, the ABS four-wheel sensor is responsible for collecting and transmitting signals. Because of its complicated and harsh environment, in order to ensure the correct transmission of pulse current signals and prevent external interference, the ABS four-wheel sensor must choose ABS special cable or stranded wire when selecting the functional wire type.

2.3 SRS Airbag System

SRS airbag system, as the standard configuration of automobile passive safety, has become an indispensable electrical component of automobile. The regular airbag requires the microprocessor to start working within 0.01s after the automobile collision, the ignition device to start within 0.03s, the high-pressure gas to enter the airbag within 0.05s, the airbag to expand outward within 0.08s, and the airbag to expand completely within 0.11s. In order for the airbag system to respond so quickly, the selection of airbag wire type is particularly important, and airbag wires are required to be airbag-specific wires. Among them, front airbag, co-pilot airbag, front seat belt pre-tightening and co-pilot seat belt pre-tightening functions should use airbag special cable or airbag special stranded wire, and left side airbag, right side airbag, left side airbag curtain, right side airbag sensor, right side airbag sensor and other functional wires should use airbag special stranded wire to eliminate their own signal interference and prevent the influence of external electromagnetic interference, and ensure the correct and timely transmission of signals.

Due to the particularity of airbag, stranded wire with excellent performance is required, and special protection is especially required in the process of making wire harness.

2.4 Car Audio System

As one of the symbols of car comfort, car audio system has been paid more and more attention by people. In order to obtain ideal sound quality, the selection of audio system wire type can not be ignored. For example, radio antenna, video cable, GPS antenna, speaker wire, etc. all have special requirements. Among them, the radio antenna is the most special, and the conductor is a single copper cord with thick insulation and external shielding. The video line and GPS antenna are multi-core shielded lines; The loudspeaker wires are twisted wires.

The use of twisted wires can ensure the sound quality of speakers and eliminate noise interference.

With the continuous improvement of automobile electronization, there will be more and more applications of special wires in automotive Wiring Harness. This paper, by Kable-X, introduces the selection of common electric wires and special wires of several main electrical systems of automobiles, for reference of peers, and expects their corrections.