Partial conversion of the large inventory of compression-ignition engines to natural-gas (NG) spark-ignition lean-burn operation can reduce U.S. dependence on imported petroleum and enhance national energy security. This paper describes some of the observations made during such an engine conversion made at the West Virginia University’s Advanced Combustion Laboratory. The engine conversion consisted from replacing the diesel injector with a spark plug and adding a port fuel injection system for NG delivery. The results indicated that the retrofitted engine performed reliably at lean-burn conditions, despite the different combustion characteristics compared to conventional SI engines. Specifically, the squish band in the original diesel chamber produced a highly-turbulent environment that accelerated flame propagation close to the top-dead-center. However, the squish region contained an important fuel fraction that burned at less-than-optimal conditions, which affected thermal efficiency and decreased combustion efficiency. Moreover, the results suggest that such engines can be optimized by increasing the bowl-to-squish volume ratio, optimizing the piston shape (such as ignoring the central protrusion and avoiding 90-degree edges inside the bowl), and using direct injection for increased volumetric efficiency.

I repeated the abstract twice more because the 400-word minimum is excessive for a preliminary abstract, in my opinion.

Partial conversion of the large inventory of compression-ignition engines to natural-gas (NG) spark-ignition lean-burn operation can reduce U.S. dependence on imported petroleum and enhance national energy security. This paper describes some of the observations made during such an engine conversion made at the West Virginia University’s Advanced Combustion Laboratory. The engine conversion consisted from replacing the diesel injector with a spark plug and adding a port fuel injection system for NG delivery. The results indicated that the retrofitted engine performed reliably at lean-burn conditions, despite the different combustion characteristics compared to conventional SI engines. Specifically, the squish band in the original diesel chamber produced a highly-turbulent environment that accelerated flame propagation close to the top-dead-center. However, the squish region contained an important fuel fraction that burned at less-than-optimal conditions, which affected thermal efficiency and decreased combustion efficiency. Moreover, the results suggest that such engines can be optimized by increasing the bowl-to-squish volume ratio, optimizing the piston shape (such as ignoring the central protrusion and avoiding 90-degree edges inside the bowl), and using direct injection for increased volumetric efficiency.

Partial conversion of the large inventory of compression-ignition engines to natural-gas (NG) spark-ignition lean-burn operation can reduce U.S. dependence on imported petroleum and enhance national energy security. This paper describes some of the observations made during such an engine conversion made at the West Virginia University’s Advanced Combustion Laboratory. The engine conversion consisted from replacing the diesel injector with a spark plug and adding a port fuel injection system for NG delivery. The results indicated that the retrofitted engine performed reliably at lean-burn conditions, despite the different combustion characteristics compared to conventional SI engines. Specifically, the squish band in the original diesel chamber produced a highly-turbulent environment that accelerated flame propagation close to the top-dead-center. However, the squish region contained an important fuel fraction that burned at less-than-optimal conditions, which affected thermal efficiency and decreased combustion efficiency. Moreover, the results suggest that such engines can be optimized by increasing the bowl-to-squish volume ratio, optimizing the piston shape (such as ignoring the central protrusion and avoiding 90-degree edges inside the bowl), and using direct injection for increased volumetric efficiency.


Lessons From the Conversion of a Heavy-Duty Compression Ignition Engine to Natural Gas Spark Ignition Operation

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

IMECE2020 - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.