Harness product design and supplier selection

The car wiring harness is the main body of the car circuit, and there is no car circuit without the wire harness. At present, whether it is a high-end luxury car or an economical ordinary car, the form of the wire harness is the same, consisting of wires, connectors and wrapping tape. Automobile wires, also known as low-voltage wires, "have been different from ordinary household wires. Ordinary household wires are copper single-core wires with a certain hardness. The car wires are all copper multi-core cords, and some cords are as thin as hair. A few or even dozens of soft copper wires are wrapped in a plastic insulating tube (polyvinyl chloride), which is soft and not easily broken.

1, automotive wiring harness design process

The main process of the pre-design stage: the calculation of the electric load of the whole vehicle. The design of the fuse beam is determined. The fuse specification is determined. The relay specification is determined. The wire specification is determined.

After the end of the pre-design phase of the online beam, enter the post-determination phase: harness trial production, adjust the design parameters, complete the product drawing, make the inspection rules, and issue the drawings and inspection rules.

1.1 Calculation of vehicle load

Actual consumption current calculation formula:

The rated working voltage of the electric appliance (the vet is not the actual working voltage. The actual operating voltage is 14.4, the actual current consumption of the electric appliance should be the rated current multiplied by the coefficient kI (k1=14. 4/ve)

K2 one electrical appliance working time relative to engine working time coefficient

P-power rating

Rated voltage of electrical appliances (ve=12 volts)

The purpose of calculating the electric load of the whole vehicle is to determine the engine power, determine the battery specification (capacity), determine the total insurance and shunt insurance, and determine the cross-sectional area of the wire. Here, it is not possible to superimpose the rated current values of all the electrical equipment, but calculate them according to a certain proportional coefficient.

1. 2 wire harness principle design is a connection method that connects all the electric equipment on the vehicle through wires, fuses, relays, switches and control devices, correctly connects with the car power supply, and ensures that each electrical device can work normally. the design of. The essence of the principle design is the design of reasonable power distribution, which is the design of how to distribute the electrical energy of the car battery or generator to the power equipment. There are mainly the following typical controls;

(1) Ignition switch control

Acc: Used to switch on electrical equipment that is not related to engine operation or vehicle travel. Such as cigarette lighter, electronic clock, radio, rear view mirror and so on.

An: Used to connect those electrical equipment related to engine operation and vehicle walking. Such as ignition systems, generators, meters, wipers, scrubbers, heaters, air conditioners, after-defrost, power windows, ahs systems, airbags, various controllers, etc

(2) Dedicated switch control

The ground control is better than the fire control: under normal circumstances, the switch control does not control the fire.

(3) Relay control

Control principle: small current control high current, timing control.

(4) Controller control

Power supply according to various controller wiring principles: clarify the definition of each pin of the controller, clarify the type of power supply required, and strictly follow the schematic wiring provided by the supplier.