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 Camelina sativa 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.
The article describes the premixed dual-fuel combustion (PDFC) realized by
dividing the Camelina sativa 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 Camelina sativa oil as an HRF for DF
engines and ethanol (LRF) under high-load conditions.
