1.1.5.1.2 Types of noise in automotive engineering Noise in automotive engineering is classified according to the intensity of the sound as follows: Low noise-low rumbling, humming sound. Moderate noise-rapid buzzing sound. Loud noise-loud howl, harsh whistle. Loud howls and whistles can stab ears. The place where sounds of different intensities are produced on the car: Low-key noise can be produced on the road, especially rough roads. This is also a form of low noise, just like the vibration of the vehicle felt by the driver.
High-profile noise (commonly known as howls and sharp whistles) is usually generated by airflow or accessories (such as generators, power steering pumps and drive belts). When the vehicle is driving on uneven roads, it will also produce a rattling sound. These unstable noises are usually caused by shock absorbers, chassis parts or loose parts in the car. 1.1.5.1.2.1 Sound is transmitted by air 1.1.5.1.2.2 Sound propagation through objects Sound is transmitted through liquids or solids (such as car bodies). The speed of sound propagation (speed of sound) depends on the material of the object.
Generally, the propagation speed of sound in liquid or solid is larger than that in air (about 5 times faster). 1.1.5.1.2.3 Sound is transmitted through air and objects Note: The noise that propagates through the air and objects together is the main concern of automotive engineering. 21 Project Part name Description 1 - Sound source 2 - Sonic 3 - Amplitude