Noteworthy research has established that the global temperatures are rising; in fact, warmer winters and warmer nights are prove to this. This is a consequence of increased carbon dioxide (from burning of fossil fuels) in the atmosphere and the resultant positive feed-back loop by the oceans. This, coupled with the finite nature of fossil fuels has triggered interest in development of alternative fuels; particularly bio-fuels. Specifically, bio-butanol –a second-generation biofuel – has been reported to be well suited as an alternative for Internal Combustion Engines due to its similar physical properties to engine fuel. As such, its potential as blend in gasoline has been widely evaluated, especially for conventional Spark Ignition engines. Regardless, there still lacks adequate data on the butanol addition effect on the spray/combustion characteristics under Gasoline Compression Ignition (GCI) conditions for gasoline.
On the bright side of things, recent reports have proven that Gasoline Compression Ignition operating mode could be a future interesting advanced combustion mode to reach higher efficiency and lower pollutant emissions than conventional Spark Ignition (SI) engines. Therefore, in line with this, researchers from the Orleans University in France: Tung Lam Nguyen (PhD candidate), Dr. Camille Hespel and Professor Christine Mounaïm-Rousselle together with Dr. Dinh Long Hoang at the Hanoi University of Science and Technology in Viet Nam examined the underlying effect of butanol blend in gasoline in injections conditions needed in GCI, via a set experimental studies, in a High Pressure/ High Temperature chamber. Their work is currently published in the research journal, Fuel.
To be specific, the objective of their work was to conduct experiments in the aforementioned High-Pressure/High-Temperature facility to characterize the effect of n-butanol on the spray and combustion processes for different butanol-PRF80 blends by considering the second injection conditions as in GCI combustion mode. In addition, they focused on unravelling the mixing and the auto-ignition processes in GCI mode under high temperature and high-pressure conditions in the case of gasoline surrogate.
The authors reported that under inert atmospheric conditions, the addition of n-butanol affected the liquid spray to a certain extent but without real impact on the vapor spray penetration evolution. On the contrary, the case on the reactive atmosphere revealed that as the content of n-butanol in the mixture decreased, the reactivity of the mixture drastically decreased.
In summary, the study presented a series of in-depth experimental investigations to explore the mixing and the auto-ignition processes in GCI mode under high temperature and high pressure conditions in the case of gasoline surrogate (PRF80) and n-butanol blends with the aim of developing an alternative bio-based fuel for currently prevalent fossil fuels. In a statement to Advances in Engineering, first author, Tung Lam Nguyen highlighted that their work revealed that butanol addition in gasoline could be a good solution in GCI combustion mode as it allows the adjustment of the combustion phasing and its optimization in engine to increase the efficiency.
Tung Lam Nguyen, Camille Hespel, Dinh Long Hoang, Christine Mounaïm-Rousselle. Butanol and gasoline-like blend combustion characteristics for injection conditions of gasoline compression ignition combustion mode. Fuel, 258 (2019) 116115.