Measurement Procedure - Brüel & Kjær 3638 Manuel De L'utilisateur

20 Exhaust Noise Inspector Type 3638 – User Manual
Cylinders
Set the number of cylinders found in the test vehicle:
1) Press
2) Press OK to confirm your selection and proceed to the next parameter.
Engine Type
Set the type of engine found in the test vehicle:
1) Press
2) Press OK to confirm your selection and proceed to the next parameter.
Criteria Level
Set the sound level maximum imposed by legislation to which the vehicle must comply:
1) Press
The default value is: 80dB(A).
2) Press OK to confirm your selection and exit the Setup menu.

Measurement Procedure

The measurement test starts with placing the vehicle in neutral gear and establishing the re-
quired RPM level as defined in applicable regulations or standards. Once Type 3638 A/B detects
the correct RPM, it automatically begins measuring the vehicle's exhaust sound level. User
intervention during measurement is minimal.
The measurement procedure is as follows:
1) Press OK to start a measurement. The display reading shows Waiting....
2) The display shows the real-time RPM value (engine speed) as soon as noise from the
exhaust is detected.
3) Operate the throttle so that the engine speed gradually increases from idle to the trigger
RPM value. The RPM Indicator LEDs can be a big help in indicating when the trigger
level is reached.
a) If the measured RPM is below the predefined RPM value range – the left red LED
lights.
b) If the measured RPM is above the predefined RPM value range – the right red LED
lights.
c) If the measured RPM is within the predefined RPM value range – the middle green
LED lights.
to scroll through numerical options: from 1 to 12.
to scroll through type options: 2 stroke or 4 stroke.
to scroll through sound level options.