Fan noise produced by the cooling fans for the radiator, alternator, and others, become louder in proportion to their rpm.
The fan noise can be produced by fan blades cutting through the air, or by air (more…)
Other Components of Engine Vibration and Sounds
Engine Mounts
Although engine mounts are relatively small, they are important in controlling NVH.
They link the vehicle body to the engine, the largest source of vibration. It is through these mounts (more…)
Engine Intake and Exhaust System Vibration and Sounds
Intake System
Intake noise includes the pulsating sound of the air taken in and the resonance sounds.
A pulsating sound has a relatively high frequency. It is determined by the air volume, shape of the (more…)
Engine Imbalance due to Inertia
Vibrating forces due to inertia forces are caused by the crank mechanism and imbalance in the rotating object.
Among the inertia-caused vibrating forces, reciprocating mass can be balanced to a certain (more…)
Torque Fluctuation due to Combustion
The vibrating force due to the combustion pressure causes torque fluctuation in the crankshaft, which is transmitted to the drive train.
It also acts upon the cylinder block as a reaction force and causes (more…)
Source of Automotive vibration Generation
As typical examples of vibrating force in a vehicle, there are the following: combustion pressure or torque fluctuation in the engine, unbalanced tires, rough road, imbalance or joint angle in the propeller (more…)
Transmission and prevention Vibration and Noise
Methods for preventing vibration or noise are as follows:
Removing the vibrating force
Stopping the resonance
Stopping the transmission
Preventing vibration and noise
etc.
Vibration or noise can (more…)
Method of Indicating Vibration, Sound, and Noise
Transmitting system
A vibration caused by a vibrating force and amplified by resonance causes the O-ring of the exhaust pipe and engine mounts to vibrate, transmitting a noise to the cabin. The passage (more…)
Automotive Resonating System
If vibrating force is applied to the spring and weight as shown in the figure, vibration rapidly becomes large when the frequency of the applied force reaches a certain frequency level. This phenomenon (more…)
How are Vibration and Noise Transmitted
Basically, vibration and sound are transmitted in the same way. Let us take a look at the process of how a vibration is generated and transmitted to the human body as a vibration or a sound. Transmission (more…)