Date of Award

2017

Document Type

Open Access Master's Report

Degree Name

Master of Science in Mechanical Engineering (MS)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Jeffrey D. Naber

Committee Member 1

Scott A Miers

Committee Member 2

Jeremy Worm

Abstract

Natural gas combined with diesel as micro pilot has the capabilities of achieving lower NOx and soot emissions. Optimization of the combustion process in engines with natural gas and diesel micro-pilot is essential to achieve higher efficiencies and loads. Gas charging (intake air boosting) and EGR are two technologies which when implemented in the natural gas-diesel engines, provide the opportunity to achieve higher efficiencies and loads and low emissions. Simulation study is one of the approaches to investigate the extent and effects of gas charging and EGR on the performance of the engine. With the rapid improvements over the past decade in the field of engine simulation and modeling, it has become an efficient, economical and reliable approach. GT-Suite, one of the widely-used Vehicle and Engine Simulation tools in the industries, provides the capabilities to calculate the combustion rate in Internal combustion engines for conventional as well as dual-fuel engines. Current research work uses GT-Suite software to study the effect of gas charging and EGR on a Cummins 2010 ISB 6.7 L engine in dual-fuel mode. One-dimensional simulation model for a Cummins 2010 ISB 6.7 L engine is developed by acquisition of dimensions from the engine. The simulation model is calibrated with the experimental data available from the diesel engine. The calibrated model is then developed into a dual-fuel model which is used to study the effect of EGR for diesel energy contribution percentages of 1,3, 5 and 10 and injection pressures of 300,600 and 1000 bar at diesel injection timings of 0° and 10° bTDC and a boost pressure of 2.5 bar. EGR levels were varied from 0-18%. Based on the simulation results for the test conditions, cases for lowest BMEP at 0° bTDC and 10° bTDC were selected and a boost pressure sweep was performed from 2.5 bar to 3 bar to study the effect of gas charging. The simulation results proved that the target BMEP of 25 bar and fuel conversion efficiency of up to 41% could be achieved in dual fuel mode for the Cummins 6.7L engine.

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