Existing low cost accelerometers for automotive applications are generally used for knock sensing. They are of two types :
The sensors of the second type are particularly interesting because they are usable for any value of knock frequency, and so, for any type of engine.
Unfortunately, the test of these sensors reveals that the frequency response has quite large dispersions in at least two frequency zones.
Consequently, the response is not as flat as supposed.
A new low cost piezoelectric accelerometer has been developped by RENAULT and RENIX.
For this sensor, described in this paper, several new tricks applied in the sensor design, contribute to a very flat frequency response up to frequencies as high as 15 KHz.