Experimental Study of Knock Control in an Internal Combustion Rankine Cycle Engine

Abstract:

Based on a retrofitted twocylinder diesel engine, combined with a selfdesigned intake and direct high temperature water injection system, the knock condition existed in internal combustion rankine cycle engine have been investigated at a high compression ratio and high oxygen fraction. The results show that compared with air intake, the knock occurred results in a high oxygen faction and the knock intensity (KIA) calculated from incylinder pressure Fourier transfer and bandpass filtering reaches 0.26 MPa. The knock frequency is controlled by utilizing a suitable direct water injection strategy and the combustion stability is sustained. Meanwhile, the injected high temperature and pressure water evaporate after heat absorption, which improves system thermal efficiency effectively.