Premixed Dual-Fuel Combustion of <italic>Camelina sativa</italic> Oil and Ethanol

Abstract

<div>Dual-fuel (DF) engines enable efficient utilization of a low reactivity fuel (LRF), usually port-injected, and a high reactivity fuel (HRF) provided directly into the cylinder. Ethanol and <i>Camelina sativa</i> oil can be ecologically effective but not fully recognized alternatives for energy production using modern CI engines equipped with a common rail system and adopted for dual fueling. The high efficiency of the process depends on the organization of the combustion.</div> <div>The article describes the premixed dual-fuel combustion (PDFC) realized by dividing the <i>Camelina sativa</i> dose and adjusting its injection timing to the energetic share of ethanol in the DF mixture. The injection strategy of HRF is crucial to confine knock, which limits DF engine operation, but the influence of EGR is also important. The research AVL engine’s dual-fueling tests focused on combustion process modification by the proposed injection strategy and cooled EGR at different substitution rates. For all examined points of the engine run, the volumetric heat release rate diagrams, cylinder pressure, and temperature illustrate changes that resulted from the tested fueling options. Additionally, engine thermal efficiency and emissions are presented. Because of potential application, the tests were confined to one engine speed (n = 1500 rpm). The research confirmed the possibility of efficiently applying raw <i>Camelina sativa</i> oil as an HRF for DF engines and ethanol (LRF) under high-load conditions.</div>