Designed to Be Green, Economic, and Efficient: A Ketone‐Ester‐Alcohol‐Alkane Blend for Future Spark‐Ignition Engines

Abstract

Model‐based fuel design can tailor fuels to advanced engine concepts while minimizing environmental impact and production costs. A rationally designed ketone‐ester‐alcohol‐alkane (KEAA) blend for high efficiency spark‐ignition engines was assessed in a multi‐disciplinary manner, from production cost to ignition characteristics, engine performance, ecotoxicity, microbial storage stability, and carbon footprint. The comparison included RON 95 E10, ethanol, and two previously designed fuels. KEAA showed high indicated efficiencies in a single‐cylinder research engine. Ignition delay time measurements confirmed KEAA's high auto‐ignition resistance. KEAA exhibits a moderate toxicity and is not prone to microbial infestation. A well‐to‐wheel analysis showed the potential to lower the carbon footprint by 95 percent compared to RON 95 E10. The findings motivate further investigations on KEAA and demonstrate advancements in model‐based fuel design.

Molecular Design of Fuels for Maximum Spark-Ignition Engine Efficiency by Combining Predictive Thermodynamics and Machine Learning

“…For modern downsized, turbocharged SI engines, the K parameter is usually negative. − Kassai et al determined values in a single-cylinder research engine with a moderate compression ratio of 10.5 between −0.1 and −1.9, with K being the lowest at high intake pressure and low engine speed. Since we aim at fuels for engines with higher compression ratios (e.g., 16.4 in our recent work), we pragmatically chose K = −1.5. In the results section, we also analyze how the choice of the K value affects the predicted efficiency gains.…”

“…In addition to technical performance and technical feasibility, the candidate fuel needs to be assessed with regard to practical constraints as an optimally designed fuel should allow for safe handling and minimum hazards to environment and health. 5 Therefore, we include the prediction of environment, health, and safety (EHS) indicators to design nonhazardous fuels. Furthermore, some computer-designed molecules are chemically feasible but challenging or even impossible to synthesize in practice.…”

“…The method was extended by early stage process design using process network flux analysis, allowing the minimization of production cost and global warming impact of the designed fuel blend . Subsequent engine testing of selected blends , has confirmed the superior engine performance compared to fossil gasoline. , …”

“…35 Subsequent engine testing of selected blends 34,36 has confirmed the superior engine performance compared to fossil gasoline. 4,5 The studies mentioned above identified promising molecules and blends based on a list of target properties. However, such a fuel design does not consider the combined effect that the individual properties exert on engine performance.…”

“…This presents an opportunity to co-optimize internal combustion engines and fuel. Engine efficiencies can be increased significantly by increasing the compression ration or turbo charging, as shown in laboratory experiments. − In advanced spark-ignition (SI) engine concepts, the achievable engine efficiency strongly depends on the autoignition tendency of the fueland thus the fuel’s molecular structure or composition. Accordingly, alternative fuels have been found to vastly outperform RON95 gasoline in single-cylinder research engines. − The molecular structure of alternative, renewable fuels can be tailored in-silico by computer-aided molecular design (CAMD) methods, representing a special case of product design. , CAMD methods combine molecule databases or molecular structure generation with predictive models to assess the suitability of a candidate molecule for a given application based on physicochemical and thermodynamic properties. , To date, fuels are usually designed for individual physicochemical property targets as surrogate measures for engine performance rather than the expected engine efficiency itself …”