Influence Study of Gas Pressure on the Volume Measurement of Engine Combustion Chamber by Using Helmholtz Resonance

The combustion chamber of automobile engine is a place where gasoline is burned to provide power for automobile driving and its size has a great influence on engine performance. However, because of the irregularity of the combustion chamber, it is difficult to measure it accurately and efficiently. The principle of Helmholtz resonance reveals the functional relationship between the volume and the resonant frequency of the closed cavity. Having used the Helmholtz resonance principle, the equipment for measuring the combustion chamber of automobile engine accurately and efficiently has been built. The conditions under which the cavity is stimulated to produce resonance are explored, the relationship between volume and the pressure is deduced. Experiments are designed to verify the correctness and accuracy of the measurement. The measuring instrument is improved and the accuracy of the volume measurement is increased. The application of the high precision and high efficiency of non-contact acoustic principle in cavity volume dynamic measurement has been realized.