Comparative study on combustion and emissions of SI engine with gasoline port injection plus acetone-butanol-ethanol (ABE), isopropanol-butanol-ethanol (IBE) or butanol direct injection

Vehicles powered by internal combustion engine are now facing stringent regulatory requirements, so it is urgent to improve engine thermal efficiency and reduce harmful emissions. Alcohols have attracted wide attention because of their renewability and cleaner emissions, and the bio-butanol is most similar to gasoline and has been widely investigated in spark ignition (SI) engine. However, the high energy consumption of separation and purification during fermentation process leads to the high price of bio-butanol. ABE and IBE are the intermediates for the preparation of butanol by different fermentation methods, and using ABE and IBE directly in SI engine will greatly reduce the cost. Combined injection is the most suitable injection approach for dual-fuel engine because the engine can flexibly control the dual-fuel injection ratio and parameters. Therefore, the combustion and emissions of gasoline/ABE, gasoline/IBE and gasoline/butanol were experimentally compared based on gasoline port injection plus alcohol direct injection mode. The results show that gasoline/IBE is better than gasoline/ABE and gasoline/butanol in power performance and brake thermal efficiency (BTE). And when the direct injection ratio (DIr) is low, the gaseous emissions of gasoline/ABE are superior, while emissions of gasoline/butanol are superior at high DIr. In addition, the particle number (PN) of gasoline/ABE is always the lowest among the three modes, and the particle basically show unimodal distribution. Overall, as direct injection fuel in dual-fuel combined injection engine, ABE and IBE have more advantages than butanol in terms of combustion and emissions performance as well as cost.

Automated summary

With the increasing regulatory requirements for vehicles powered by internal combustion engines, improving engine thermal efficiency and reducing harmful emissions has become urgent. Alcohols, known for their renewability and cleaner emissions, have attracted wide attention. Among them, bio-butanol, which is most similar to gasoline, has been widely studied in spark ignition (SI) engines. However, the high energy consumption during the separation and purification process in the fermentation of bio-butanol results in its high price. ABE and IBE, as intermediates for the preparation of butanol through different fermentation methods, can be directly used in SI engines, significantly reducing the cost. Combined injection is the most suitable injection approach for dual-fuel engines, as it allows flexible control of the dual-fuel injection ratio and parameters. Therefore, this study experimentally compared the combustion and emissions of gasoline/ABE, gasoline/IBE, and gasoline/butanol using gasoline port injection plus alcohol direct injection mode. The results show that gasoline/IBE performs better in terms of power performance and brake thermal efficiency (BTE) compared to gasoline/ABE and gasoline/butanol. Moreover, when the direct injection ratio (DIr) is low, the gaseous emissions of gasoline/ABE are superior, while emissions of gasoline/butanol are superior at high DIr. In addition, the particle number (PN) of gasoline/ABE is the lowest among the three modes, and the particles exhibit a unimodal distribution. Overall, as direct injection fuel in dual-fuel combined injection engines, ABE and IBE have more advantages than butanol in terms of combustion and emissions performance as well as cost.