How to measure car fan noise? How can you tell if a car fan is normal?

The noise of the Taiwan Bi-Sonic fan was measured in a non-reverberating chamber with a background noise of less than 15 dB. The fan to be tested runs in free air, and a noise meter is disposed of one meter away from the air inlet.

The sound pressure level is based on the background factor and is represented by the following formula:

SPL = 20 P Pref and SWL = 10 W WREF

where p = sound pressure.

pref = reference sound pressure.

w = noise energy of the sound source.

wref = noise energy of the sound source.

The noise level of a fan is usually plotted in the octave of the sound pressure level (SPL). The effect of a change in decibels (DBA) is shown by the following signs:

3 dba barely felt.

5 dba felt out.

10 dba feels twice as loud.

Noise level: 0 20 dB Very faint.

20 40 dB is faint.

40 60 dB moderate.

60 80 dba loud.

80 100 dB is loud.

100 140 dba is deafening.

The following guidelines provide fan users with best practices to minimize noise:

System impedance

The range between the air inlet and outlet of a chassis accounts for 60% to 80% of the total system impedance, and the larger the airflow, the higher the relative noise. The higher the system impedance, the greater the airflow required for cooling, so the system impedance must be reduced to a minimum in order to minimize noise.

Turbulence Turbulence Disturbance caused by obstructions along the path of the airflow can produce noise. Therefore, any obstructions, especially in the critical air inlet and outlet areas, must be avoided in order to reduce noise.

Fan speed and size.

Since high-speed fans produce more noise than low-speed fans, low-speed fans should be tried and selected whenever possible. A larger, lower-speed fan is usually quieter than a smaller, higher-speed fan delivering the same amount of air.

Temperature increase Within a system, the amount of air required for cooling is inversely proportional to the allowable temperature rise. By allowing a slight increase in temperature rise, the required air volume can be significantly reduced. Therefore, if the imposed limits on permissible temperature rise are relaxed slightly, the required airflow can be reduced and the noise level can be reduced.

Vibration In some cases, where the weight of the entire system is very light, or when the system has to operate in a prescribed manner, it is particularly advisable to use soft insulation equipment to avoid the transmission of fan vibrations.

Voltage Fluctuations Voltage fluctuations can affect the level of noise. The higher the voltage applied to the fan, the higher the vibration and the louder the noise generated as the speed increases.

Design considerations.

The design of each component that makes up the fan affects the noise level. Noise reduction can be achieved by considering the size of the winding core, the design of the fan blades and frames, and the precise manufacturing and balancing.

It can be measured with a sound level meter, such as Taiwan's 1350A. You can also drive the car to the Metrology Bureau to find inspectors to measure with a sound level meter.

1. Judge by listening to the sound in the engine compartment. Because the fan makes a whirring sound when it is working, even next to the engine, if you listen carefully close to the engine compartment, you can hear the sound of the fan. If the fan doesn't turn, you won't be able to hear the sound.

2. By observing the operation of the fan. Since the fans are basically installed at the front of the engine compartment, it is also very convenient to observe the fixed position. So you just need to see if the car fan is turning, or feel the fan with your hands to see if the fan is blowing out.

But be careful not to put your hand in the fan blades.

3. Observe by the temperature of the water. In general, the cooling system will cut into the large circulation after the water temperature reaches 80 degrees, and the fan will rotate, so it is judged according to the water temperature gauge on the dashboard. If the fan still doesn't turn after reaching the specified temperature, then it's time to consider checking the fan.

In this way, combined with the temperature of the car engine, it is normal for the fan to turn around 95 degrees.

Such a problem generally depends on the water temperature of the car, if the water temperature is normal, the fan must be normal, if the water temperature is high, the fan is not normal, I don't understand or go to the repair shop to see, the fan is not running, if the water temperature is high temperature has a great impact on the engine!

First of all, it is judged by the temperature and pressure of the air conditioning. If the water temperature reaches 100 degrees, the fan will run at a low speed when the air conditioning is turned on. If the water temperature reaches 112 degrees, the fan will run at high speed. In addition, it can be judged by diagnostic instruments.

Car fans are cooling fans, some have one fan blade, and some have two fan blades, mainly depending on the heat dissipation requirements of the car. The cooling fan has two functions:1.

cooling engine coolant; The coolant from the vibrator is circulated through the radiator, and the fan is right next to it. The fan carries away the heat around the radiator by accelerating the air flow, and the direction of the wind is blown by the fan towards the engine side. 2.

Cooling of condenser pipes in air conditioning system: There are two sets of heat sinks in the air intake grille of our car, one is coolant and the other is condenser pipe, which changes the refrigerant from high temperature and high pressure gas to medium temperature and medium pressure to disperse the liquid. So the condenser tube needs to dissipate excess heat, just like the external unit of our home air conditioning system.

The power supply current of the cooling fan is KL30, which can be started at any time, do not rashly judge whether it is running or stuck by touch, otherwise it is easy to hurt yourself. If you need to tell if the fan is stuck, disconnect the battery's electrodes. There are two speed gears for the cooling air fan:

High and low gears. Low gear is usually used when the vehicle is driving at low speeds. If the empty compressor starts working, the cooling fan will go into high gear.

Millions of car purchase subsidies.