HC and CO emissions of premixed low-temperature combustion fueled by blends of diesel and gasoline

HC and CO emissions in a premixed low-temperature combustion mode fueled by blends of diesel and gasoline are investigated in this study. Tests were conducted on a single-cylinder direct-injection diesel engine, with gasoline proportion in fuel blends and engine control parameters (EGR rate, intake pressure and injection pressure) adjusted to investigate their influences on HC and CO emissions of this premixed low-temperature combustion mode. It is found that changes in fuel composition and engine parameters affect ignition delay and global equivalence ratio, which are closely tied to HC and CO emissions, respectively. The methods that extend ignition delay, such as increasing EGR rate, increasing gasoline proportion in fuel blends, or reducing intake pressure, cause increased HC emissions. In contrast, for most cases, CO emissions are dominated by global equivalence ratio, which is mainly adjusted by EGR and intake pressure. (C) 2012 Elsevier Ltd. All rights reserved.