Experimental Study of Diesel Engine Cycle-to-Cycle Variation—Part II: Correlation of Ignition Delay and Cylinder Pressure Variation

Abstract

Marine diesel engine excitation can occur from the cycle-to-cycle variation in the engine output. The cycle-to-cycle variation in maximum cylinder pressure is often used to represent this variation. Recent tests indicate a poor correlation between the variation in maximum pressure and variation in pressure impulse (PI). This paper summarizes the results of systematic experiments to determine the cycle-to-cycle variation in maximum cylinder pressure, ignition delay (ID), and corresponding ignition pressure in a single-cylinder test diesel engine at various rpm and compression ratios. Comparisons show that there is a high correlation between the cycle-to-cycle variation in ID and PI. Consequently, the variation in the ignition delays should be used instead of the maximum pressure.