Apparatus for sensing Schnarren phenomenon in fuel injection line

摘要

A sensor (16) produces an electrical signal corresponding to the pulsating pressure in a high pressure fuel line (13) leading to a fuel injection valve (14), the pulsations being produced by opening and closing of the valve (14). The electrical signal and a reference signal are fed to a cathode ray tube display unit (18) to produce a Lissajous figure. The shape of the Lissajous figure indicates whether the Schnarren phenomenon is present and, if so, to what extent. The frequencies or amplitudes of the electrical signal and reference signal are compared to produce a signal indicating the difference therebetween which is fed to a digital display unit (22).