Procedure for studying the natural frequencies of the valve mechanism of the internal combustion engine

Abstract

Operational reliability, efficiency, active safety, and environmental qualities of a car are largely determined by the operation of its engine. Therefore, the search and study of new diagnostic methods that allow quickly, as simple as possible, and reliably identifying faults is an urgent task. The justification for this statement can be carried out experimental studies of vibration of an internal combustion engine (ICE). As a result of these studies, ICE vibration was found to be acoustic in nature. It is proved that it is possible to use the directional microphone EM-8800 and the acoustic noise recorder of the 1st class Robotron 00023 as a sensitive element of the ICE valve mechanism diagnostics system. The exploratory partial survey runs on a full-scale Ford V1.3 8-valve engine and SpectraLAB software built on a base PC using a handheld vibration analyzer. Due to this, it became possible to obtain the amplitude-frequency response over the entire audible sound range from 100 Hz to 20 kHz. Experimental studies have confirmed that the EM-8800 directional microphone has a wide dynamic range of the measured signal of 70dB and a high ultimate sound pressure level of 150 dB. It was also found that the natural frequencies of the intake and exhaust valves of the car ICE are in the frequency range of 4-5 kHz.