Operating range characterization and expansion of premixed charge compression-ignited combustion in a multi-cylinder diesel engine with variable valve actuation, variable fuel reactivity and revised turbomachinery

David J Fain, Purdue University

Abstract

As will be demonstrated in this thesis, premixed charge compression ignition combustion (PCCI) offers reduction of NOx and PM emissions, reduces the need for expensive and efficiency limiting exhaust aftertreatment systems, improves engine efficiency, and increases exhaust gas temperature to improve aftertreatment thermal management. This work presents two extensive studies of realistic limits to the PCCI operating space that can be achieved on a multi-cylinder diesel engine when the methods of variable valve actuation, reduced fuel reactivity, and revised turbomachinery are employed. This study is a unique contribution to the field of PCCI in that it was conducted with hardware and methods that are reasonably production viable, within the context of limits on emissions and engine performance that ensure beneficial engine operation, across a wide speed and load range. A single direct injected fuel was delivered with one standard fuel system and standard air handling configurations were used. Other PCCI studies consider test cells that use multiple fuel systems with up to 18 fuel injectors and custom air-handling configurations with multiple EGR loops and external EGR coolers. A variable valve actuation system was used in this study, but only IVC timing was modulated by a maximum of 50 CAD. Further, this study was conducted with strict emissions constraints for tailpipe NOx and engine out UHC, CO, and PM that are consistent with the use of a DOC and DPF. Limits on pressure rise rate were also placed to ensure quiet and safe operation of the engine. These comprehensive limits and considerations revealed the portion of the engine operating space in which beneficial PCCI can be achieved with reasonably production viable methods. Further the extensive range over which the study was performed, the widest range considered when compared to other published PCCI limit studies, provides unique insight on the factors that limit effective PCCI at different operating conditions. (Abstract shortened by ProQuest.)

Degree

M.S.M.E.

Advisors

Shaver, Purdue University.

Subject Area

Mechanical engineering

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