I had the privilege of visiting Ford’s development centre in Dearborn, Michigan earlier this year during the Detroit Motor Show. Ford wanted to show us some of the technologies they used in their car development and one of them is Noise Vision, a system that they use to help reduce the interior noise levels of Ford vehicles.
We were lucky that we were allowed photography in the centre. Most manufacturers ban cameras in all of their facilities and it makes it really hard for us to tell a story once we are back at our workstations.
The black device you see is nicknamed Pythagoras by Ford employees, but its officially called the Noise Source Identification Tool, or Noise Vision. As you can see, it is a small black sphere and it is placed inside a vehicle cabin.
Covering the surface of Pythagoras are more than 30 highly sensitive microphones and 12 special cameras. The system of microphones are directional so they can measure the direction of sound as well as the volume of sound.
Placed outside the car in the lab area, this is the view that Pythagoras provides the Noise Vision’s computer system. It’s basically a 360 degree view of the place, which doesn’t really tell much at this point of time because the sound measurement hasn’t been activated yet. The Ford engineers who was demo-ing Noise Vision to us then placed a small sound generation device in the room – I think it was a metronome.
And this is what we were able to see on Noise Vision. The exact source of the sound has been pinpointed, and you also get to see the volume level of the sound here using graphics that simulate thermal imaging. I drive car that’s more than 10 years old and as you can expect, the interior has started to squeak and rattle here and there especially when I drive over the typical Semi-Value kind of roads.
But all I hear are squeaks and rattles and I can’t exactly pinpoint where the rattles are coming from. Using Noise Vision, I would be able to pinpoint the exact source of sound and try to fix it. That’s exactly what Ford’s engineers are doing.
So anyway, it was time to show give us a demo on how Noise Vision works. Before they do anything, the Ford engineers will tape up the obvious sound leak holes of the car such as the rubbers and seals at the doors and etc. This is to get the car interior down to the most silent condition that’s logically possible. Then Noise Vision is used to see where else the external noise leaks in.
I’m not sure what that device you see in the boot does (is it an industrial vacuum cleaner?) but for this exercise all it’s supposed to do is become a source of sound. The device was turned on and then we proceeded to look at what kind of data Noise Vision was giving us.
And this is the result generated by the 360 degree Noise Vision system inside the car. As you can see, there seems to be actually two predominant spots where the sound from the device in the boot is leaking through into the cabin. Both are somewhere around the rear speakerboard but one part seems to be leaking much more sound than the other.
The engineer can then zoom in to that particular area of the interior where you can see the sound sources clearer. Ford now knows that those two spots near the rear speakerboard are leaking sound into the interior, so it can work on perhaps some better seals in that area. In this case for demonstration sake, an engineer patched the two areas with something.
The Noise Vision test was ran again and here’s the new result – much less sound coming in through the boot. Basically this process is repeated and repeated with a cabin in its original state in a wind tunnel or on the road or whatever conditions they would like to test it in, and the interior sealing is refined until they get the noise levels down to the quietest possible!
“The key to world-class interior quietness is to pinpoint the source and location of every unwanted sound, no matter how subtle it is. We used to rely on trial and error to make a vehicle quieter. It was a process of elimination that often led us to mask the issue with thicker glass or more sound insulation. Noise Vision litreally shows us where the noise is and allows us to eliminate it once and for all. Noise Vision already is paying off for Ford, with the new 2010 Taurus, Fusion, Flex and F-150 achieving the quietest interiors in their class,” said Bill Gulker, Ford’s leader of Wind Noise Engineering.
Noise Vision is not revolutionary. Some other manufacturers use such a system as well and I managed to dig out at least two names – Mazda and Nissan. But of all the big three US automakers, Ford is the first to use such a system. I can’t believe there are still some companies using trial and error? But in any case it has allowed Ford’s North American NVH engineers to reduce 200 hours of wind tunnel testing time a year which translates into US$300,000 in testing costs. It may not be unique but there you have it – an insight into the R&D process of achieving better interior NVH thanks to Ford!