Book Description

Abstract : The gasoline compression ignition (GCI) works on the principle of harnessing the benefits of light distillates in a compression ignition (CI) engine. Recent research has shown that along with air management and after-treatment systems; fuel systems also play a vital role in enabling GCI technology. The injector in the fuel injection system (FIS) is a key component driving the efficiency of the combustion phenomena. Subsequently, injection strategies, characteristics, and overall injection quality influence the combustion process and controls certain metrics like fuel consumption, pollutant emissions, and combustion noise. In this work, a one-dimensional (1-D) model of a heavy-duty diesel injector employed in Cummins ISX15 Engine, built in a commercially available computer software called Gamma Technologies (GT)-SUITE, was studied, and analyzed. This work focuses on developing a generalized methodology from previous work to adapt this injector with gasoline-like fuels by recalibrating the discharge coefficients using in-built GT-SUITE optimization techniques. Post recalibration, the 1-D model closely reproduces experimentally measured injection performance characteristics like rate of injection (ROI) profiles, injected quantities, hydraulic delays, and needle lift profiles for the heavy-duty, high-pressure diesel injector using gasoline-like fuels across engine operating points of interest, thereby enabling GCI. As the previous study has demonstrated the potential of injection rate shaping in the mitigation of oxides of nitrogen (NOx) emissions, this validated 1-D model was further used to investigate various injector geometries to produce custom injection rate shapes. Finally, an optimization methodology was developed to generate rate shape of interest to obtain a single set of the selected dimensional parameters across high-efficiency engine operating points using the in-built GT-SUITE optimization techniques. Furthermore, a full factorial design of experiments (DoE) using the candidate injector geometries, hydraulic components were simulated and post-processed to obtain an optimal rate shape, thereby acting as a validation tool for the optimal rate shape obtained using GT-Suite's optimization methods.