As the nerve center of a car, the wiring harness system plays an important role in connecting the central control components and various electrical appliances in the car. The design quality of the wiring harness system directly affects the safety of the vehicle. With the increasingly popular automotive market and the rapid development of the electronics and electrical industry, the rapid increase in automotive electronics and electrical appliances, combined with people's increasing requirements for vehicle safety, comfort, economy, and emissions, the application of wiring harness in cars is becoming more and more widespread, and designing the wiring harness system for automobiles is becoming more important and strict.
During the overall vehicle concept design and structural design phases, overall wiring harness layout awareness should be integrated, and preliminary planning should be done. The battery, fuse box, and central control components should be concentratedly arranged, which can not only save the cost of the main wiring harness and reduce the overall vehicle weight, but also improve the wiring harness layout aesthetics and greatly reduce the risk of car fires.
The wiring harness system should be modularized based on the overall function and characteristics of the vehicle, making it easy to disassemble, maintain, and save vehicle maintenance and repair time. The three-dimensional wiring diagram of a passenger car's wiring harness system is divided into 11 modules: engine wiring harness, starter cable wiring harness, front wiring harness, instrument wiring harness, roof light wiring harness, left front door wiring harness, left middle door wiring harness, right front door wiring harness, right middle door wiring harness, tailgate wiring harness and chassis wiring harness.
When laying out auto parts wiring harnesses, sharp edges, high temperatures, oil lines, water pipes, and moving parts areas should be avoided to ensure reliability. If it cannot be avoided, appropriate protective measures must be taken. For example, in the engine compartment, the engine wiring harness should fully consider the problem of engine vibration and heat radiation around the exhaust manifold. A fixed point needs to be set every 200mm, and the distance from the heat source should not be less than 100mm. Additional heat shields should be added between the wiring harness and heat sources, and heat-resistant corrugated pipes should be used to bundle the wiring harness. Door wiring harnesses should focus on factors such as through-holes, seals, and assemblies. When drilling through a hole, a plastic protective sleeve should be used to prevent the wiring harness from losing its function due to wear. They should be arranged on the inside of the door to prevent water leakage from affecting the wiring harness. Use as few clips as possible to fix as many wiring harnesses as possible to reduce the complexity of opening holes and assembling on the body.
In areas where electromagnetic interference is strong or signal sensitive, attention should be paid to adding electromagnetic protection to the wiring harness, and setting up double-twisted or shielded wires for conductors, such as the CAN bus. Due to interference from internal electronic control components in cars, the CAN bus is exposed to external electromagnetic environments that change from low frequency to high frequency, so higher requirements are placed on the anti-interference ability of the CAN bus. CAN bus, as a data reliable transmission line, ensure its good anti-electromagnetic interference characteristics are particularly important.
Most car electrical faults are caused by grounding failure, usually poor grounding contact or grounding wire breakage. Therefore, the design of each electrical equipment grounding point in the car circuit should be based on the nature and function of the electrical equipment and reasonably arranged to ensure the good working condition of each electrical equipment in the car.
The grounding points of electrical equipment that have a large impact on the overall vehicle performance and safety and are susceptible to interference from other electrical equipment must be set up separately, such as the engine, ECU, ABS, etc. Grounding points for weak signal sensors or signal sensitive electrical equipment should be set up separately to keep the circuitry as short as possible and ensure the true transmission of signal, such as audio and other radio systems. Grounding points for high-current electrical equipment should also be set up separately to ensure nearby grounding, shorten the circuit length, and reduce voltage drop and electromagnetic interference.
In order to improve the reliability of key electrical equipment on the car that affects personal safety, double grounding is used, such as the airbag system to ensure its accurate and timely operation.
General auto parts wiring harness electrical appliances can selectively share grounding points based on their three-dimensional layout, environment, to reduce assembly complexity and material costs.