Truck sound level range

The range of sound level of freight cars is 69-80 decibels, and the control of automobile noise can be started from two aspects: reducing bicycle noise and controlling automobile flow. Bicycle noise is mainly determined by the noise of engine, cooling fan, tire and road friction; The noise of domestic car horns is often10-15db higher than that of cars, reaching105db; In addition, the speed also has a great influence on the noise.

Engine is the main noise source of automobile. Noise of direct injection diesel engine, indirect injection diesel engine, gasoline engine and Stirling engine with a distance of 1 meter. From the point of view of reducing automobile noise, it is obvious that gasoline engines are better than diesel engines. However, since 1970s, diesel engine has become the development trend of automobile power because of its advantages in energy saving and pollution emission. Foreign countries predict that before 1985, diesel trucks will grow at a rate of 6%, and diesel cars will grow at a faster rate of 15~ 17%. After that, the domestic market demand and the dynamics of scientific research and production units also attached great importance to the development of diesel vehicles. Therefore, it is necessary to narrow the noise gap between diesel engine and gasoline engine as much as possible. As for Stirling engine, as a potential competitor of traditional internal combustion engine, it is also in a favorable position in noise control. China has listed it as one of the long-term key research projects.