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.

Key words:internal combustion engine; internal combustion rankine cycle; oxyfuel; direct water injection; knock control