Methanol Fuel Testing on Port Fuel Injected Internal-Only EGR, HPL-EGR and D-EGR Engine Configurations

摘要

The primary focus of this investigation was to determine the hydrogen reformation, efficiency and knock mitigation benefits of methanol-fueled Dedicated EGR (D-EGR) operation, when compared to other EGR types. A 2.0 L turbocharged port fuel injected engine was operated with internal EGR, high-pressure loop (HPL) EGR and D-EGR configurations. The internal, HPL-EGR, and D-EGR configurations were operated on neat methanol to demonstrate the relative benefit of D-EGR over other EGR types. The D-EGR configuration was also tested on high octane gasoline to highlight the differences to methanol. An additional sub-task of the work was to investigate the combustion response of these configurations. Methanol did not increase its H_2 yield for a given D-EGR cylinder equivalence ratio, even though the H:C ratio of methanol is over twice typical gasoline. Although the methanol H_2 reformate yield did not increase over gasoline for a given equivalence ratio, the total yield did increase due to an extended rich misfire limit of the dedicated cylinder. Methanol-fueled D-EGR extended the maximum load of the engine by 2 bar BMEP. It also improved CoV of IMEP, increased dilution tolerance, improved combustion efficiency, and improved thermal efficiency. Cooled EGR also suppressed hot spot pre-ignition of methanol.