Investigation of propane direct injection performance in a rapid compression and expansion machine: Pathways to diesel marine engine efficiency parity with spark discharge duration strategies.

This paper explores pathways to achieve marine diesel-like, high-efficiency combustion fueled with propane in a RCEM research engine. Analyzing the novel technique of liquid propane injection is worthwhile given the potential for using propane in high-efficiency compression ignition engines. Since propane has a low cetane number, spark plug operating is provided to achieve reliable ignition. Investigations into combustion and the effect of spark discharge energy on propane direct injection were done through experiments on a modified head large bore RCEM with three spark ignition strategies and simulations. The findings demonstrate that the simultaneous ignition strategy had the greatest total released energy (roughly 190 mJ/s). When the SOI of the direct injection propane was set at 20oCA BTDC, diesel more efficiently than propane (on average, 3.46%). The benefits of the chosen strategy for achieving diesel efficiency parity were shown by the increasing of combustion efficiency when the spark period was lengthened. • In-cylinder combustion, performance characteristics and spark discharge energy were investigated. • Spark ignition was applied on RCEM research engine fueled with liquid propane direct injection. • Investigating the in-cylinder flow and velocity distribution around spark plug. • Spark plug ignition duration was investigated to achieve reliable ignition and reasonable ignition delays. • RCEM with spark produces high in-cylinder pressure when the SOI of liquid propane direct injection was set at 20 oCA BTDC. [ABSTRACT FROM AUTHOR]