With the development of domestic automobile manufacturing technology and automobile wiring harness production technology, it is particularly important to consider the selection of wiring harness from the aspects of wire type, wire temperature resistance grade, wire cross-sectional area, wire color, and wire voltage drop verification.

1. Twisted pair and shielded wire

The wire type should be determined according to the requirements of the components connected to the wiring harness in the circuit. For general power signals and strong and difficult to interfere signals, ordinary wires can meet the signal quality requirements; for some weak signal circuits and signal circuits that are easy to interfere, twisted pair or shielded wires should be selected. The weak signal circuit mainly refers to the knock sensor, crankshaft sensor, gear position sensor, gear position sensor, clutch controller position sensor, etc. , And vulnerable signal circuits mainly refer to airbag circuits, ABS circuits, speakers on CD players, CAN cables, etc.

Second, the type of automotive wiring harness

To determine the wire harness selection of automobile wiring harness, the wire structure and insulation material properties corresponding to different standards are different. According to meeting the standard requirements of the target market, select the line type suitable for automotive products. At present, the main line types are FLRY, AVSS, American and National Standard (QVR). The German standard wire has thin insulation and good flexibility; the national standard wire is characterized by thick, soft, and good ductility; the insulating sheath of the American standard wire is generally thermoplastic or thermosetting elastomer, and part of it is irradiated. The AVSS line is made of thin-skinned insulating material, which has good flexibility. The appropriate wire type can be selected according to user needs and different working environments.

3. Wire temperature resistance rating

According to the working environment temperature of the wire harness of the car, choose wires of different temperature resistance grades. For example, the operating temperature standard for AVSS conductors in Japan is 80°C for AVSS conductors and 120°C for AEX conductors. The conductor in the cabin can meet the requirements. For example, automotive wiring harnesses on automatic transmissions must be resistant to high temperature, hydraulic oil, and good temperature stability. The wire harness used for the brake shoe wire harness should be resistant to wear, impact (silt) and high and low temperature (temperature cycling). The temperature field can be used to obtain the temperature resistance requirements of the automobile driving area, and then the selected wire type can be determined according to the temperature resistance level of various wires.

Fourth, determine the cross-sectional area of the wire

When determining the cross-sectional area of the wire, the influence of voltage and wire heating should be considered. Of course, the cross-section of the conductor can also be directly selected by the rated current of the conductor. The cross-sectional area of the wiring for various electrical appliances in the automobile can be appropriately selected according to the load current of the electrical appliances used. Under normal circumstances, long-term power equipment can choose 60% of the actual current carrying capacity

For short-time work of power equipment, wires with an actual carrying capacity of 60%- can be used. At the same time, factors such as voltage drop and conductor heating in the circuit should be considered to avoid affecting the electrical performance of the equipment and the allowable temperature of too many wires. The cross-section of the low-voltage conductor is generally not less than 0.5 mm to ensure a certain mechanical strength.

Five, the color of the wire harness

With the increase of automobile electrical equipment, more and more wires are installed in automobiles. In order to facilitate identification and later maintenance, the wires of automobile wiring harnesses are often distinguished by colorless. Each area will use a different letter code to indicate different harness colors. For details, see the latest national car wiring harness color code encyclopedia.