Analysis of the Coefficient of Variation for Injection Pressure in a Compression Ignition Engine

Pressure variability in injection pipes (pw) supplying fuel to a diesel engine cylinder was analyzed. Pressure levels were recorded at the injector nozzle. To define the variability of pressure, coefficients of variation for the injection pressure (COVpw) recorded during the operation of the engine were evaluated. The results demonstrated that coefficients of variation COVpw can be used to find the start of injection. Uncertainties of the results were analyzed. The test results included the data for the mineral or bio-fuel powered engine operating at full load condition within the speed range from 1000 to 2000 rpm.