On-Engine Demonstration of Micro-Pilot Ignition System for Cooper-Bessemer GMV-4TF (DOE Research Review)
This investigation assesses the benefits of retrofitting a diesel micro-pilot ignition system on a Cooper-Bessemer GMV-4TF two-stroke cycle natural gas engine. The pilot fuel injectors are mounted through an adaptor in one of the spark plug holes in a set of dual-spark plug heads. A high-pressure, common-rail, diesel fuel delivery system is employed and customizable power electronics control the current signal to the pilot injectors. Pilot fuel is supplied by a variable displacement, high-pressure pump that is driven with an electric motor. Software is developed that interfaces with the pump and controls and monitors the fuel rail pressure. Micro pilot quantities from 1 to 20 mm3 are explored at rail pressures from 200 to 1400 bar. Three independent variables (pilot ignition timing, pilot fuel quantity, and pilot fuel rail pressure) are manipulated. Two optimal settings for these variables are found: one to minimize NOx emissions and one to minimize total modified fuel consumption.