An experimental research on the determination of the combustion characteristics of ABE fuel in a port injection HCCI engine

Recent studies have shown that the use of n-butanol, a type of long-chain alcohol, in internal combustion engines yields highly promising results. However, the production efficiency of bio-butanol is low and quite costly. Therefore, researchers suggest using butanol in the ABE (acetone-butanol-ethanol) format without purification until a more cost-effective and efficient method of bio-butanol production is found. This study examined the effects of ABE and n-heptane mixtures on the operating range, combustion phase, and emissions in an HCCI mode. Tests were conducted at intake temperatures of 310 K and 350 K, at variable lambda values and engine speeds. ABE content and increased intake temperature allowed for the extension of homogeneous charge compression ignition (HCCI) mode operating range. The widest operating range was obtained with ABE20 at intake temperature of 350 K. Conventional HCCI combustion, which happens at small crank angles, was slowed down and controlled by ABE. Slow oxidation reactions cause the indicated thermal efficiency to increase. The highest indicated thermal efficiency was determined as 43.73 % by using ABE40. However, carbonmonoxide and hydrocarbons emissions, which are the biggest drawbacks of HCCI engines, increased with ABE mixture fuels. In conclusion, ABE demonstrated the potential to be promising biofuel for HCCI engines.