What are the raised lines on the car hood?
3 Answers
The raised lines on the car hood are vibration markings. Here is the relevant introduction: 1. Vibration markings: Their shape is concave-convex, with a base plus protruding part height of 5-7mm. They are usually made in dot or strip shapes, producing a "rumbling" sound when vehicles pass over them, serving as an excellent warning and reminder for drivers, hence also called noise markings. Compared to the sound produced by speed bumps (iron-made), they are much gentler. It is a high-tech product with internationally advanced standards currently widely used in developed countries. 2. Function of vibration markings: To remind drivers to follow the lane and reduce speed. They help prevent driver fatigue and achieve mandatory speed reduction, thereby improving driving safety.
We often overlook the lines on the car hood while driving, but they are actually called reinforcement ribs or crease lines, primarily designed to enhance the hood's strength. Think about it—the hood is such a large sheet of metal. If it were completely flat, over time or when driving at high speeds with wind pressure, the center would easily deform or dent. These raised lines act like a skeleton supporting the entire hood, especially reducing vibration-induced deformation when driving over bumpy roads. Additionally, they help direct airflow, ensuring rainwater flows off without pooling. I’ve seen older cars without this design, and after a few years, their hoods sag noticeably, looking quite unattractive. During manufacturing, these features are easily formed through stamping. Nowadays, almost all new cars incorporate this design—it’s both practical and gives the vehicle a more rugged appearance.
These raised lines are quite useful in terms of aerodynamics. When the car is moving, the airflow hits the front of the vehicle. A flat hood would cause the airflow to scatter chaotically, increasing wind resistance and causing issues with fuel consumption and noise. The ridges act like tracks, neatly guiding the airflow backward, significantly reducing resistance, especially at high speeds. I've observed this in a wind tunnel lab—the airflow over a hood with ridges is much smoother. Additionally, this design aids in heat dissipation. When hot air from the engine passes through the hood, the air flowing along the grooves can carry away more heat. Some sports cars have numerous ridges for maximum drag reduction, while family cars only need a few to balance aesthetics and functionality.
