auto wire harness arrangement principle

1.1 Preliminary planning

In the conceptual design and structural design phase of the vehicle, we must integrate the overall layout awareness of the wiring harness and do a good job in planning. The battery, the fuse box, and the central control unit can be arranged in a centralized manner, which not only saves the cost of the trunk wiring harness, reduces the overall quality of the entire vehicle, improves the aesthetics of the wiring harness arrangement, but also greatly reduces the risk of burning cars.

1.2 Modularization

The wiring harness system should be modularized according to the functions and characteristics of the complete machine, which facilitates disassembly and assembly, facilitates maintenance, and saves vehicle maintenance and repair time. 2 is a three-dimensional wiring diagram of a passenger car harness system, which is divided into engine harness, starting cable harness, front harness, meter harness, ceiling lamp harness, left front door harness, left center door harness, right front door harness, right There are 11 modules in the door harness, tailgate harness, and chassis harness.

1.3 layout environment

When wiring harness is arranged, sharp edges, high temperature, oil paths, water pipes and moving parts should be avoided to ensure the reliability of layout. If you cannot avoid it, you must take appropriate protective measures. If the engine compartment, engine wiring harness should fully consider the engine vibration, heat radiation around the exhaust manifold, a fixed point must be set every 200mm, the distance from the heat source should not be less than 100mm, before the wiring harness and heat source additional heat shield, wiring harness External high-temperature bellows dressing. The door harness should take into account the hole, seal, assembly factors, etc., through the use of plastic protective sleeve, to prevent the malfunction caused by the wear and tear of the harness; try to be arranged on the dry side of the door to prevent the impact of water leakage on the harness; use as little as possible Get buckled to secure as many harnesses as possible, reducing the opening and assembly complexity on the body.

1.4 Electromagnetic Interference Protection

In areas with strong electromagnetic interference or signal-sensitive areas, attention should be paid to adding anti-magnetic protection to the wiring harness and setting the wires to twisted-pair or shielded wires, such as a CAN bus. Because the internal electronic control component of the car interferes with the CAN bus, it is in an external electromagnetic environment that changes from a low frequency to a high frequency, and therefore a higher requirement is imposed on the anti-interference capability of the CAN bus. As a CAN bus with reliable data transmission, it is particularly important to ensure its good anti-electromagnetic interference characteristics.

1.5 Grounding Design Principles

Most of the automotive electrical faults are caused by the failure of grounding, which is usually caused by bad ground connection or broken wire. Therefore, the design of the galvanic points of all electrical equipment in the automotive circuit must be rationally arranged according to the nature and function of the electrical equipment in order to ensure the good working conditions of the electrical equipment on the vehicle.

(1) The traction points of electrical appliances that have a large impact on vehicle performance and safety and are vulnerable to interference with other electrical appliances must be set up separately, such as engines, ECUs, ABS, etc.; weak-signal sensors or electrical appliances that are vulnerable to interference should be separate Set up a ground point, try to make the shortest electrical circuit, to ensure the real signal transmission, such as radio systems such as audio; high current electrical appliances have to be set up separately, to ensure that the loop near the ground, shorten the loop length, reduce the voltage drop Electromagnetic interference is safe and economical.

(2) In order to improve the reliability of key electrical appliances that affect people's safety in automobiles, dual-type ground irons, such as airbag systems, are used to ensure accurate and timely operations.

(3) General use of electrical appliances can be based on its three-dimensional layout of the location, the environment, optional common ground, reducing the complexity of the assembly and material costs.