Performance Of A Laser Ignited Multicylinder Lean Burn Natural Gas Engine

Abstract

Market demands for lower fueling costs and higher specific powers in stationary natural gas engines have engine designs trending toward higher in-cylinder pressures and leaner combustion operation. However, ignition remains as the main limiting factor in achieving further performance improvements in these engines. Addressing this concern, while incorporating various recent advances in optics and laser technologies, laser igniters were designed and developed through numerous iterations. Final designs incorporated water-cooled, passively Q-switched, Nd:YAG microlasers that were optimized for stable operation under harsh engine conditions. Subsequently, the microlasers were installed in the individual cylinders of a lean-burn, 350 kW, inline six-cylinder, open-chamber, spark ignited engine, and tests were conducted. The engine was operated at high-load (298 kW) and rated speed (1800 rpm) conditions. Ignition timing (IT) sweeps and excess-air ratio (λ) sweeps were performed while keeping the NOx emissions below the United States Environmental Protection Agency (USEPA) regulated value (brake-specific NOx (BSNOx) < 1.34 g/kW h), and while maintaining ignition stability at industry acceptable values (coefficient of variation of integrated mean effective pressure (COV-IMEP) < 5%). Through such engine tests, the relative merits of (i) standard electrical ignition system and (ii) laser ignition system were determined. A rigorous combustion data analysis was performed and the main reasons leading to improved performance in the case of laser ignition were identified.

Publication Date

11-1-2017

Publication Title

Journal of Engineering for Gas Turbines and Power

Volume

139

Issue

11

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1115/1.4036621

Socpus ID

85021171517 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85021171517

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