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Title: Fundamental Studies of Ignition Process in Large Natural Gas Engines Using Laser Spark Ignition

Abstract

Past research has shown that laser ignition provides a potential means to reduce emissions and improve engine efficiency of gas-fired engines to meet longer-term DOE ARES (Advanced Reciprocating Engine Systems) targets. Despite the potential advantages of laser ignition, the technology is not seeing practical or commercial use. A major impediment in this regard has been the 'open-path' beam delivery used in much of the past research. This mode of delivery is not considered industrially practical owing to safety factors, as well as susceptibility to vibrations, thermal effects etc. The overall goal of our project has been to develop technologies and approaches for practical laser ignition systems. To this end, we are pursuing fiber optically coupled laser ignition system and multiplexing methods for multiple cylinder engine operation. This report summarizes our progress in this regard. A partial summary of our progress includes: development of a figure of merit to guide fiber selection, identification of hollow-core fibers as a potential means of fiber delivery, demonstration of bench-top sparking through hollow-core fibers, single-cylinder engine operation with fiber delivered laser ignition, demonstration of bench-top multiplexing, dual-cylinder engine operation via multiplexed fiber delivered laser ignition, and sparking with fiber lasers. To the best of ourmore » knowledge, each of these accomplishments was a first.« less

Authors:
;
Publication Date:
Research Org.:
Colorado State University
Sponsoring Org.:
USDOE
OSTI Identifier:
939620
DOE Contract Number:
FC26-02NT41335
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; EFFICIENCY; ENGINES; FIBERS; IGNITION; IGNITION SYSTEMS; LASERS; NATURAL GAS; PERFORMANCE; SAFETY; TARGETS; TEMPERATURE DEPENDENCE

Citation Formats

Azer Yalin, and Bryan Willson. Fundamental Studies of Ignition Process in Large Natural Gas Engines Using Laser Spark Ignition. United States: N. p., 2008. Web. doi:10.2172/939620.
Azer Yalin, & Bryan Willson. Fundamental Studies of Ignition Process in Large Natural Gas Engines Using Laser Spark Ignition. United States. doi:10.2172/939620.
Azer Yalin, and Bryan Willson. Mon . "Fundamental Studies of Ignition Process in Large Natural Gas Engines Using Laser Spark Ignition". United States. doi:10.2172/939620. https://www.osti.gov/servlets/purl/939620.
@article{osti_939620,
title = {Fundamental Studies of Ignition Process in Large Natural Gas Engines Using Laser Spark Ignition},
author = {Azer Yalin and Bryan Willson},
abstractNote = {Past research has shown that laser ignition provides a potential means to reduce emissions and improve engine efficiency of gas-fired engines to meet longer-term DOE ARES (Advanced Reciprocating Engine Systems) targets. Despite the potential advantages of laser ignition, the technology is not seeing practical or commercial use. A major impediment in this regard has been the 'open-path' beam delivery used in much of the past research. This mode of delivery is not considered industrially practical owing to safety factors, as well as susceptibility to vibrations, thermal effects etc. The overall goal of our project has been to develop technologies and approaches for practical laser ignition systems. To this end, we are pursuing fiber optically coupled laser ignition system and multiplexing methods for multiple cylinder engine operation. This report summarizes our progress in this regard. A partial summary of our progress includes: development of a figure of merit to guide fiber selection, identification of hollow-core fibers as a potential means of fiber delivery, demonstration of bench-top sparking through hollow-core fibers, single-cylinder engine operation with fiber delivered laser ignition, demonstration of bench-top multiplexing, dual-cylinder engine operation via multiplexed fiber delivered laser ignition, and sparking with fiber lasers. To the best of our knowledge, each of these accomplishments was a first.},
doi = {10.2172/939620},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jun 30 00:00:00 EDT 2008},
month = {Mon Jun 30 00:00:00 EDT 2008}
}

Technical Report:

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  • The current report details project progress made during the first quarterly reporting period of the DOE sponsored project ''Fundamental studies of ignition processes in large natural gas engines using laser spark ignition''. The goal of the overall research effort is to develop a laser ignition system for natural gas engines, with a particular focus on using fiber optic delivery methods. In this report we present our successful demonstration of spark formation using fiber delivery made possible though the use of novel coated hollow fibers. We present results of (high power) experimental characterizations of light propagation using hollow fibers using bothmore » a high power research grade laser as well as a more compact laser. Finally, we present initial designs of the system we are developing for future on-engine testing using the hollow fibers.« less
  • The US Department of Energy-Office of Heavy Vehicle Technologies (now the DOE-Office of FreedomCar and Vehicle Technologies) signed an Interagency Agreement (IAA) with National Institute for Occupational Safety and Health (NIOSH), No.01-15 DOE, 9/4/01, for 'The analysis of genotoxic activities of exhaust emissions from mobile natural gas, diesel, and spark-ignition engines'; subsequently modified on 3/27/02 (DOE IAG No.01-15-02M1); subsequently modified 9/02/03 (IAA Mod No. 01-15-03M1), as 'The analysis of genotoxic activities of exhaust emissions from mobile internal combustion engines: identification of engine design and operational parameters controlling exhaust genotoxicity'. The DOE Award/Contract number was DE-AI26-01CH11089. The IAA ended 9/30/06. Thismore » is the final summary technical report of National Institute for Occupational Safety and Health research performed with the US Department of Energy-Office of FreedomCar and Vehicle Technologies under that IAA: (A) NIOSH participation was requested by the DOE to provide in vitro genotoxicity assays of the organic solvent extracts of exhaust emissions from a suite of in-use diesel or spark-ignition vehicles; (B) research also was directed to develop and apply genotoxicity assays to the particulate phase of diesel exhaust, exploiting the NIOSH finding of genotoxicity expression by diesel exhaust particulate matter dispersed into the primary components of the surfactant coating the surface of the deep lung; (C) from the surfactant-dispersed DPM genotoxicity findings, the need for direct collection of DPM aerosols into surfactant for bioassay was recognized, and design and developmental testing of such samplers was initiated.« less
  • To improve the efficiency of spark-ignition engines, high-compression engines can be fitted with a knock detector for controlling the ignition timing. Such detectors are already used extensively for structure-borne noise. Engine developers complain, however, that previous methods are not sensitive enough. Cheaper, more efficient components now make it possible to use more complex detectors, which are tailored to the problem, instead of less effective, heuristic methods. In the paper an optimal - in a certain sense - detector is presented and its efficiency is examined. The detector is based on a signal model verified by measurements which contains several combustionmore » chamber resonance modes. It consists of a time axis transformation, appropriate weightings in the time and frequency domain and a Fourier transform.« less
  • Requirements for alternatives to diesel-fueled vehicles are developing, particularly in urban centers not in compliance with mandated air quality standards. An operator of fleets of diesel- powered vehicles may be forced to either purchase new vehicles or equip some of the existing fleets with engines designed or modified to run on alternative fuels. In converting existing vehicles, the operator can either replace the existing engine or modify it to burn an alternative fuel. Work described in this report addresses the problem of modifying an existing diesel engine to operate on natural gas. Tecogen has developed a technique for converting turbochargedmore » automotive diesel engines to operate as dedicated spark-ignition engines with natural gas fuel. The engine cycle is converted to a more-complete-expansion cycle in which the expansion ratio of the original engine is unchanged while the effective compression ratio is lowered, so that engine detonation is avoided. The converted natural gas engine, with an expansion ratio higher than in conventional spark- ignition natural gas engines, offers thermal efficiency at wide-open- throttle conditions comparable to its diesel counterpart. This allows field conversion of existing engines. Low exhaust emissions can be achieved when the engine is operated with precise control of the fuel air mixture at stoichiometry with a 3-way catalyst. A Navistar DTA- 466 diesel engine with an expansion ratio of 16.5 to 1 was converted in this way, modifying the cam profiles, increasing the turbocharger boost pressure, incorporating an aftercooler if not already present, and adding a spark-ignition system, natural gas fuel management system, throttle body for load control, and an electronic engine control system. The proof-of-concept engine achieved a power level comparable to that of the diesel engine without detonation. A conversion system was developed for the Navistar DT 466 engine. NOx emissions of 1.5 g/bhp-h have been obtained.« less
  • Since natural gas (mostly methane) is readily available and enjoys a favorable cost advantage through lower taxes and some price regulations, the popularity of conversion of gasoline engines to natural gas has increased significantly in recent years. However, fuel cost rather than energy efficiency has been the primary motivation behind these engine conversions, and little emphasis has been placed on the anti-knock, wide flammability, and emissions characteristics of methane. A data base was established in Phase I utilizing a wedge-shaped combustion chamber to show effects of equivalence ratio, ignition timing, and compression ratio for engine operation on natural gas whosemore » primary component was methane. Baseline performance data were obtained for engine operation on research grade indolene and natural gas. The reoptimization process for the engine operating on natural gas fuel included determining minimum best torque spark timing as a function of equivalence ratio from 120% of the stoichiometric fuel rate to the lean limit fuel rate for a range of compression ratios from 8.4:1 to 18.5:1. The optimum compression ratio for the wedge-shaped combustion chamber was selected based on data for both part throttle and wide-open throttle operation. In Phase II, a hemispherical combustion chamber was used to show the effects of changing combustion chamber configuration on the pertinent engine operating parameters.« less