Date of Award


Document Type

Open Access Master's Thesis

Degree Name

Master of Science in Mechanical Engineering (MS)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Jeffrey Naber

Committee Member 1

Jaclyn Johnson

Committee Member 2

Seong-Young Lee


Recent developments in internal combustion engine technology have shown that gasoline compression ignition (GCI) combustion modes provide a viable pathway to meet future emission regulations. Lower octane middle distillate gasoline like fuels have also been formulated for GCI combustion applications and have shown similar benefits of improved fuel conversion efficiency and a reduction in particulate matter and nitrogen oxide emissions. As these gasoline like GCI fuels have not been well studied, characterization of their rate of injection (ROI) will be beneficial to supplement injector spray characterization measurements and the development of computational fluid dynamic simulations. A fuel collection method and data processing technique were defined to develop a measurement procedure for making rate of injection measurements with a Bosch type rate of injection (ROI) rig. The measurement procedure was developed to quantify the ROI for both heavy duty (HD) and light duty (LD) injector applications.

The HD studies included ROI measurements using an Ultra-Low Sulfur Diesel (ULSD) and a research octane number (RON) 60 gasoline compression ignition (GCI) fuel. Rate of injection measurements for the HD fuels were obtained with an eight-hole high pressure common rail diesel Cummins XPI injector and electronic injection durations were successfully calibrated to provide a desired fuel quantity per injection. Single-hole ROI measurements were also made with a Cummins XPI injector designed to provide one-eighth of the flow of the multi-hole injector. These single-hole ROI measurements were used to supplement injector spray characterization data in an optically accessible combustion vessel.

The LD studies characterized ROI measurements of a custom ten-hole Bosch HDEV5 gasoline direct injection (GDI) injector. The LD fuels studied were a premium octane CARB LEV III 10% ethanol (E10) certification gasoline and a RON 70 GCI fuel. These LD studies were conducted to compare the RON 70 GCI fuel’s ROI characteristics to those of the premium octane CARB LEV III E10 certification gasoline. Average trends showed higher rates of injection and total mass per injection for the premium octane E10 cert gasoline and was attributed to the higher density of the fuel. Conclusions were also made that the higher viscosity of the E10 cert gasoline provided longer injector opening delays when compared to the RON 70 GCI fuel.