Glued Functions - Based Assessment of Interpolation Accuracy of Self-Ignition Engine Real Indicator Diagram

Abstract

The paper aims to provide an analysis and accuracy assessment of the interpolation of real indicator diagrams, averaged over 50 runs, performed with the use of glued functions which analytically describe the form of those diagrams. The analysis and accuracy assessment were carried out for values of mean indicated pressure p¬i and indicated efficiency determined for real and interpolated diagrams. The paper also presents the analysis and assessment of error in the determination of the mean maximum pressure value in the working cycle of the AD3.152 UR engine fuelled by diesel oil, pure methyl ester of rapeseed oil fatty acids FAME and the blend of both fuels marked B20. When the indicator diagram was taken experimentally, the engine operated in the mode of external speed characteristics at the crankshaft rotational velocity n=2000 rpm.

Evaluation of the Uncertainty of Selected Parameters that Characterise Diesel Engine Work

“…The experimental studies were described in [4]. In the experiments, the values of injection pipe pressure, in-cylinder pressure and the needle lift were recorded for 50 working cycles of the Perkins AD3.152 UR compression-ignition engine.…”

“…During the engine's operation in all strokes, 25600 combustion chamber pressure values were recorded [4]. The plot in Fig.…”

Determining selected diesel engine combustion descriptors based on the analysis of the coefficient of variation of in-chamber pressure

“…Table 1 summarizes the selected technical parameters of this engine [18]. During the tests, pressure p c was measured using the piezoelectric sensor AVL QC34D.…”