Combustion noise determining device for e.g. oil engine of motor vehicle, has filtering module implementing band-pass function by low-pass module and high-pass module, whose cut-off frequency is less than that of low-pass module

摘要

#CMT# #/CMT# The device has a digital calculation unit (16) calculating a combustion noise value (Br) from a pressure value provided by a combustion pressure sensor (13) via a band-pass filtering module (22) and a sampling module (50). The module (50) is formed by an analog-to-digital converter. The module implements a band-pass function on a preset frequency band representing noise by digital low-pass and high-pass filtering modules (221, 222). The module (221) ensures an anti-aliasing function for sampling frequency. The module (222) has cut-off frequency less than that of the low-pass filtering module. #CMT#USE : #/CMT# Device for determining combustion noise in a cylinder of a direct or indirect fuel injection type rotary internal combustion engine such as oil engine, of a motor vehicle. Can also be used for a petrol engine of the motor vehicle. #CMT#ADVANTAGE : #/CMT# The configuration of the device permits rapid and continuous determination of the combustion noise in the cylinder of the rotary internal combustion engine of the motor vehicle in a real time, during moving of the motor vehicle. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a modular block diagram of a band-pass filtering module of a combustion noise determining device. Br : Combustion noise 13 : Combustion pressure sensor 16 : Digital calculation unit 22 : Band-pass filtering module 50 : Sampling module 221 : Digital low-pass filtering module 222 : Digital high-pass filtering module.