Courtesy Toyota
The majority of customers expect a smooth, quiet ride. When noise, vibration or harshness issues arise, a methodical diagnostic approach can pinpoint the root cause.
Noise/vibration/ harshness Chasing the irritant gremlins Part one of two
By Mike Mavrigian
A
host of various noise and vibration issues normally exist during the operation of any vehicle. However, when levels of these factors become noticeable to the customer, he or she may perceive any annoying noises and/or vibrations as problems. NVH (noise, vibration and harshness) is the commonly-used term used when discussing these conditions. In some cases, any noise or harshness complaints may stem from the vehicle owner’s perception, or their expectations of how the vehicle should behave. The NVH condition that is a concern does
not need to be the strongest vibration or the loudest noise. It could be one that has recently developed and was not previously present. As an example, tire tread noise from a vehicle equipped with large tread block tires might be acceptable to the owner of a 4x4 who recognizes this as a natural by-product, while others may fnd this as totally unacceptable. A complaint on the same vehicle could be much more subtle, caused by a driveline problem. Because we sense vibration and sound using different senses, we tend to discuss them separately. However, vibration and sound are essentially identical. A sound is a vibration (pressure fuctuation) of the air. Vibrations and sounds are
22 | January/February 2013
