Access Type

Open Access Thesis

Date of Award

January 2014

Degree Type

Thesis

Degree Name

M.S.

Department

Mechanical Engineering

First Advisor

Marcis Jansons

Abstract

Low temperature combustion (LTC) modes of operating internal combustion engines are of great interest for their potential to achieve high thermal efficiencies while maintaining low nitrogen oxide (NOX) and particulate matter emissions below levels requiring costly after-treatment systems. While various strategies for realizing LTC have been developed, including homogeneous charge compression ignition (HCCI), reactivity controlled compression ignition (RCCI) and premixed charge compression ignition (PCCI), a common challenge is the control of the kinetically-driven auto-ignition processes over appreciable load ranges.

This study examines the chemical kinetics of split-injection timing and the kinetic effect of this parameter on combustion phasing and pressure rise rate. Detailed reaction mechanisms are applied in CHEMKIN-based kinetic simulations to model the production and composition of combustion intermediates produced by a pilot injection through different pressure-temperature histories. The influence of these intermediates on the combustion phasing of the following main fuel ignition is examined. Different pilot injection timings were tried keeping the main fuel addition timing constant. The temperature, pressure and rate of heat release profiles during the combustion cycle for varied pilot fuel injection timings were compared along with the species composition at the start of main fuel addition. The results will provide insight to the role of pilot injection timing on LTC control.

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