A comparative study of multiple tests based techniques for optimal sensor location for knock detection

A comparative study of techniques for finding optimal sensor positions in a group of vibration sensors for knock detection in spark ignition engines is presented. The methods assume the transmission of the acoustical oscillations in the combustion chamber to the engine housing to be time invariant and linear. Based on this model, suitable multiple tests have been performed to reject sequentially irrelevant sensors from the sensor group under consideration. It was found in various simulations that two of the proposed methods that do not assume any probability distribution of the data lead to the expected results. In a real experiment performed on a test bed using a four cylinder spark ignition engine, the two methods reveal the same optimal sensor location for monitoring knock in two cylinders at three different speeds.