What we would like to do in this section is to relate how we join together
The comments and complaints of a customer owner driver
With the use and application of NVH
So Steve
The NVH software is wizard driven so it is a question of answer the question
Yes or no then next
We will run through this as if you have received a vehicle
With a customer complaint of vibration
No other information than that so we will keep this
As a 3 axis vibration measurement
So where do we start how do we tackle a vibration measurement
If you have an essentials kit you can skip this step
This is your licence key your scope will already be unlocked
But if you have bought it as an accessory
Then you will need an NVH licence key
Simply to obtain the key you will need the serial number from you PicoScope
And the serial number from one of you NVH interfaces
Contact the technical support@picotech.com and they will issue the licence key
I do know Steve that when I got my NVH kit it came pre licensed
Is the licence chargeable is it something we have to pay for
Or does it expire after a certain date
No not at all Frank
The licence is free one licence with one NVH scope
Once you have entered the licence key
The scope will work indefinitely
It is the scope that is unlocked not the PC
So if you change the PC or you change software
The licence remains with the scope
It is the scope that remains unlocked for NVH use
The first step of vibration analysis is to obtain engine speed and road speed
And the simplest way to get engine speed and road speed is
Via the OBD connector
So the software is going to ask you which protocol
We use J2534 for light vehicle
Heavy goods and commercial that will be J1939
Or there is an option for a universal ELM lead
But be aware that that will not work on a lot of vehicles
It is an option that is there and is available certainly if you have an ELM lead
There are other options in there
Square wave so you can actually put a speed signal into channel D of the scope
And if you do not have a crank sensor for example for your speed signal
You could use static RPM and enter an RPM value
We use Mongoose remember so it is our MongoosePro ISO CAN2
We plug that into the diagnostic connector
We click J2534
Click next
And the Mongoose will confirm that it is connected to the vehicle
It will give use the chassis number
And we also have displayed RPM there
OK I am going to run through the rest of the Wizard on my PC
Here we have the option if we want to
We can skip this but we can add the transmission style
The number of gears the ratios
It is an all wheel drive vehicle
Our ratio for this vehicle 2.8 for the rear diff and the same for the front diff
There is a question here about 5th and 6th gear ratios
Some transmissions have a different final drive for 5th and 6th gear
Tyres there is an option to enter different tyre sizes front and rear
225 /40 /R19 it is important that you write in that configuration
So it would be 225 forward slash 40 R 19
If the format is wrong you will see the exclamation mark there
It is a 3 channel interface because the starter standard and advanced NVH kits
All come with the 3 channel NVH interfaces
We are connecting an accelerometer
If you tap the accelerometer you will see the activity there in the bar graph
That confirms that the accelerometer is functioning
Mount the accelerometer in the vertical orientation with the screw thread facing forward
That ensures that all axis of vibration are detected correctly
And that is completion of the set up wizard
And there you are that is a summary of all the information you will need to enter
Frank you mentioned earlier about the advanced if you need to enter more information
Yes if you go into the advanced sub section of this screen
You are then able to put a great deal more information in
Specific gear ratios pulley ratios of various devices fitted to the vehicle
Essentially the more information that you put in
The higher the level and quality of the results you will get
When you are analysing the test data
So it is always worth perhaps trying to get gear ratios
As well as other information if possible
OK so a quick summary there
3 channel interface into 3 channels of PicoScope
So that is X Y X into A B C
Accelerometer mounted on the seat frame
The way in which the vibration is affecting the vehicle will be determined
We will be able to identify if it is the vertical the fore and aft or the lateral
Mounting point once again
And then the animation will take us through the road test
So here we will be able to see the set up
How the accelerometer is mounted
And the data that we obtain from a road test
Bear in mind that this vehicle does have a vibration
So there is our 3 axis of vibration data
Detected from the seat frame
In all 3 axis
And here we are in road test
As you can see there is a T1 vibration
Very high in the vertical that is the red bar graph
We are looking at the bar graph view here
Also you can see there there is a high E2 the blue bar graph
That is typical of combustion
It is a four cylinder engine so it will have two combustion events
For one revolution of the crankshaft
Quite normal we will talk about that as we move on through
But I think we can safely say here looking at this data
We have a T1 first order vibration from a component rotating at tyre speed
And that is what is essential
Looking at the same data but in the frequency view now
We stop the capture here at mid way
We are at 73 miles per hour
We have an engine speed of 1800 RPM
An again it is looking at the same data but in a different view
I do like this view because we can see a lot of activity from unknown vibrations
Looking at the bar graph view we specify only the vibrations of interest
For example T E and P vibrations
It might be worth mentioning that the scaling of this information
Can be changed very easily just by focusing the cursor on the relevant
Scale you wish to change and just drag it along the screen so you can
Hone in on a higher level of quality of information
There is a lot of information to take in initially when you are using NVH
For example if you do not use it that often what does T1 mean
Simple placing your cursor over T1 there will
Open up a sub help menu that will explain T1
And then you can click onto a further menu to give you a full description of a T1 vibration
And the kind of things that you would be looking for in this scenario
Thank you