Why the cause of white smoke can be determined by oil loss via the valve guides
(1) The negative pressure of the intake manifold is high when the engine is idle, so oil is sucked into the combustion chamber (more…)
Why the cause of white smoke can be determined by oil loss via the valve guides
(1) The negative pressure of the intake manifold is high when the engine is idle, so oil is sucked into the combustion chamber (more…)
Imbalance
Imbalance in the propeller shaft causes vibration or noise, like in tires. The propeller shaft turns faster than tires by the gear ratio of the differential gear. Therefore, the frequency of (more…)
Tire uniformity refers to uniformity of weight, dimensions and rigidity.
However, since uniformity of weight is ordinarily called “wheel balance” and uniformity of dimensions is called “run-out” uniformity (more…)
Since a tire is made by bonding together rubber, there is a in difference in the rubber thickness, the circumference of the tire is not a perfect circle.
Even if the tire is perfectly circular, if the (more…)
Due to the weight unbalance of the rotating object, a centrifugal force is generated during rotation, which results in a vibrating force.
This vibrating force increases in proportion to the square of (more…)
The vibrating force caused by tires can be classified into two cases; the tire itself generates the vibrating force and uneveness on the paved road cause a vibrating force.
Tire itself generates vibrating (more…)
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…)
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…)
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…)
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…)