2002 Prius High-Pitched Howl Noise at speed

Hi Kocho,

The 6 to 10 KHz tone at the beginning I have not heard in my 2006. The pitch varying regeneration noise as you decellerate sounds just like my car tho.

The high pitched tone does not sound mechanical to me. Its probably an inverter sound, but it could be motor lamination, or winding noise. As the current pumps through, it creates mechanical forces (F=qVxB) on the windings and if they can move, they will. This would cause the sound, which would propagate through the housings and into the air. Laminations can vibrate too. Ever heard an only buzzy transformer? The Toyota engineers had to come up with some inovations to get the inverter noise down to what it is according to their public record of the Prius developement. What the inovations are was not described. I would think that older cars would tend to loosen up and start to make that noise.

I was out for a walk in my neighborhood one day, and had something come up behind me making that very noise, only louder. I turned around and it was a very new RX450H. They have MUCH more inverter noise than a Prius.

As people with older Prius cars are noticing the same thing, I would not be too concerned. Its not very loud at all, in comparison to other road noise.

 

I have an '02 with 80K miles on it and mine has made that sound since I bought it in '04. Just thought it was letting me know it was different.... not your average car on the road sound.... No problems expected... jf B)

 

Y'all have got me all paranoid now. I was in a long glide to a stop,
and started hearing a louder descending whine from somewhere. Turned
out to be a jet passing overhead just at the right rate.
.
_H*

 

I'll have another listen tomorrow morning for youand get back with a report.

 

<div class='quotetop'>QUOTE(Kocho @ Oct 23 2007, 08:05 AM) [snapback]529236[/snapback]</div>

I used AudaCity, a freeware download, to look at the data where the noise was clearest. The spectrum analysis suggests the frequency is closer to 6 kHz. It might be interesting to play it through an equalizer and see if the frequency audio band can be identified. I tried Quicktime but it doesn't have a strong frequency filter.

It does sound a mixed result. Some folks hear it and others, like me, are free. The laminate hypothesis makes sense.

Bob Wilson

 

I can just hear some noise when accelerating lightly on electricity only and it's louder on the brake lightly.