Performance Analysis of a Natural Gas Generator Using Laser Ignition

2004 ◽  
Author(s):  
Munidhar S. Biruduganti ◽  
Sreenath B. Gupta ◽  
Bipin Bihari ◽  
Gregory Klett ◽  
Raj Sekar
Keyword(s):  
Natural Gas ◽  
Optical Fibers ◽  
High Pressures ◽  
Gasoline Engine ◽  
Pressure Rise ◽  
Laser Pulses ◽  
Laser Ignition ◽  
Solid Core ◽  
Gas Generator ◽  
Ignition Characteristics

A single cylinder spark ignited gasoline engine was modified to operate with natural gas. In such an engine, laser ignition was successfully demonstrated while transmitting the high-power laser pulses via solid core optical fibers. Subsequently, ignition studies were performed while using laser ignition (LI) and conventional spark ignition (SI). However, due to limitations imposed by the engine hardware the adverse conditions for ignition could not be simulated, i.e., of lean operation and high-pressures. As a result, the scope of the study was limited to comparing LI and SI ignition characteristics at various ignition timings. It was observed that both LI and SI resulted in reliable combustion over all ignition timings. Furthermore, LI resulted in higher rates of pressure rise and higher peak cylinder pressures. However, the higher NOx emissions resulting from such conditions might not be representative as the final performance of an engine as it is determined by optimizing ignition timing and other operating parameters.

Design and Bench-Top Testing of Multiplexed Fiber Delivered Laser Ignition System for Natural Gas Engines

2007 ◽  
Author(s):  
Sachin Joshi ◽  
Adam Reynolds ◽  
Bryan Willson ◽  
Azer P. Yalin
Keyword(s):  
Natural Gas ◽  
Fiber Optics ◽  
Optical Fibers ◽  
Pressure Rise ◽  
Past Research ◽  
Laser Pulses ◽  
Solid Core ◽  
Cyclic Variability ◽  
Natural Gas Engines ◽  
Silica Fibers

Past research has demonstrated the feasibility of using optical sparks for engine ignition, and has shown potential benefits associated with reduced cyclic variability and increased rate of cylinder pressure rise, thus extending the lean operating limit of natural gas engines. This contribution details the design and bench-top testing of a fiber-optic delivery system for ignition of natural gas engines. The system is designed for use on a Caterpillar G3516C engine and is comprised of a single Nd:YAG laser as the energy source, a multiplexer for switching the beam between cylinders, fiber optics to deliver the laser pulses to individual cylinders, and optical plugs to couple the beam into the cylinders. The optical fibers are a critical component of the system and discussion of use of both solid core silica fibers and cyclic olefin polymer-coated silver hollow fibers is included. The multiplexer design is presented and optical testing of the multiplexed fiber delivery on the bench-top is reported. Design considerations for engine integration are introduced.

Development of a Fiber Delivered Laser Ignition System for Natural Gas Engines

2006 ◽  
Author(s):  
Azer P. Yalin ◽  
Adam R. Reynolds ◽  
Sachin Joshi ◽  
Morgan W. Defoort ◽  
Bryan Willson ◽  
...  
Keyword(s):  
Natural Gas ◽  
Fiber Optics ◽  
High Efficiency ◽  
Low Cost ◽  
Laser Pulses ◽  
Hollow Fibers ◽  
Laser Source ◽  
Laser Ignition ◽  
Design Development ◽  
Natural Gas Engines

Laser ignition is viewed as a potential future technology for advanced high-efficiency low-emission natural gas engines. However, in order to make laser ignition systems more practical, thereby enabling them to transition from the laboratory to industrial settings, there is a need to develop fiber optically delivered ignition systems. Recent work at Colorado State University has shown the possibility of using coated hollow fibers for spark delivery and has demonstrated laser ignition and operation of a single engine cylinder using hollow fiber delivery. In order to practically operate a multiple cylinder engine, we envisage a simple and low-cost system based upon a single laser source being delivered (“multiplexed”) through multiple fibers to multiple engine cylinders. In this paper, we report on the design, development, and initial bench-top testing of a multiplexer. Bench-top testing showed that the multiplexer can be positioned with the required accuracy and precision for launching into fiber optics, and can be switched at the relatively high switching rates needed to operate modern natural gas engines. Another test employed the multiplexer to alternately launch laser pulses into a pair of hollow fibers in a way that allows spark creation downstream of the fibers.

scholarly journals Effect of flow velocity and temperature on ignition characteristics in laser ignition of natural gas and air mixtures

2015 ◽  
Vol 66 ◽  
pp. 132-137 ◽  
Author(s):  
J. Griffiths ◽  
M.J.W. Riley ◽  
A. Borman ◽  
C. Dowding ◽  
A. Kirk ◽  
...  
Keyword(s):  
Natural Gas ◽  
Flow Velocity ◽  
Laser Ignition ◽  
Ignition Characteristics

Transportation of megawatt millijoule laser pulses via optical fibers?

Open Physics ◽  
2010 ◽  
Vol 8 (2) ◽  
Author(s):  
Johannes Tauer ◽  
Heinrich Kofler ◽  
Elisabeth Schwarz ◽  
Ernst Wintner
Keyword(s):  
Laser Beam ◽  
Optical Fibers ◽  
Internal Combustion Engines ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Pollutant Emissions ◽  
Laser Ignition ◽  
Combustion Engines ◽  
Future Concepts ◽  
Pulsed Laser Beam

AbstractLaser ignition is considered to be one of the most promising future concepts for internal combustion engines. It combines the legally required reduction of pollutant emissions and higher engine efficiencies. The igniting plasma is generated by a focused pulsed laser beam. Having pulse durations of a few nanoseconds, the pulse energy E p for reliable ignition amounts to the order of 10 mJ. Different methods of laser ignition with an emphasis on fiber-based systems will be discussed and evaluated.

Laser Ignition of Methane-Air Mixtures at High Pressures and Diagnostics

2005 ◽  
Vol 127 (1) ◽  
pp. 213-219 ◽  
Author(s):  
Herbert Kopecek ◽  
Soren Charareh ◽  
Maximilian Lackner ◽  
Christian Forsich ◽  
Franz Winter ◽  
...  
Keyword(s):  
Natural Gas ◽  
Nd:Yag Laser ◽  
High Pressures ◽  
Laser Energy ◽  
Spectroscopic Technique ◽  
Laser Ignition ◽  
Pulsed Nd:Yag Laser ◽  
Natural Gas Engines ◽  
Spark Plug ◽  
Induced Ignition

Methane-air mixtures at high fill pressures up to 30 bar and high temperatures up to 200°C were ignited in a high-pressure chamber with automated fill control by a 5 ns pulsed Nd:YAG laser at 1064 nm wavelength. Both, the minimum input laser pulse energy for ignition and the transmitted fraction of energy through the generated plasma were measured as a function of the air/fuel-equivalence ratio (λ). The lean-side ignition limit of methane-air mixtures was found to be λ=2.2. However, only λ<2.1 seems to be practically usable. As a comparison, the limit for conventional spark plug ignition of commercial natural gas engines is λ=1.8. Only with excessive efforts λ=2.0 can be spark ignited. The transmitted pulse shape through the laser-generated plasma was determined temporally as well as its dependence on input laser energy and properties of the specific gases interacting. For a first demonstration of the practical applicability of laser ignition, one cylinder of a 1 MW natural gas engine was ignited by a similar 5 ns pulsed Nd:YAG laser at 1064 nm. The engine worked successfully at λ=1.8 for a first test period of 100 hr without any interruption due to window fouling and other disturbances. Lowest values for NOx emission were achieved at λ=2.05 NOx=0.22 g/KWh. Three parameters obtained from accompanying spectroscopic measurements, namely, water absorbance, flame emission, and the gas inhomogeneity index have proven to be powerful tools to judge laser-induced ignition of methane-air mixtures. The following effects were determined by the absorption spectroscopic technique: formation of water in the vicinity of the laser spark (semi-quantitative); characterization of ignition (ignition delay, incomplete ignition, failed ignition); homogeneity of the gas phase in the vicinity of the ignition; and the progress of combustion.

Ignition Characteristics of Methane-Air Mixtures at Elevated Temperatures and Pressures

2005 ◽  
Author(s):  
Gregory M. Klett ◽  
Sreenath Gupta ◽  
Bipin Bihari ◽  
Raj Sekar
Keyword(s):  
High Pressures ◽  
Elevated Temperatures ◽  
Current Knowledge ◽  
Laser Ignition ◽  
Rapid Compression Machine ◽  
Lean Burn ◽  
Engine Design ◽  
Mode Of Operation ◽  
Ignition Characteristics ◽  
Lean Conditions

Lean operation of natural gas fired reciprocating engines has been the preferred mode of operation as it allows low NOx emissions and simultaneous high overall efficiencies. In such engines, the operation point is often close to where the ignition boundary and the knock limiting boundary cross-over. While knocking is, to a large extent, limited by engine design, ignition of lean-mixtures is limited by the mode of ignition. Since significant benefits can be achieved by extending the lean-ignition limits, many groups have been researching alternate ways to achieve ignition reliably. One of the methods, laser ignition, appears promising as it achieves ignition at high pressures and under lean conditions relatively easily. However, most of the current knowledge about laser ignition is based on measurements performed at room temperature. In this paper, ignition studies on methane-air mixtures under in-cylinder conditions are presented. A Rapid Compression Machine (RCM) was designed to reproduce typical in-cylinder, conditions of high temperature (∼ 490°C) and pressure (∼ 77 Bar) at the time of ignition. Experiments were performed comparing conventional coil based ignition (CDI) and laser ignition on methane-air mixtures while varying pressure and equivalence ratio systematically. It was observed that substantial gains are possible with the use of laser ignition as it extends the lean-ignition limit to the flammability limit, i.e., φ = 0.5. On the other hand, conventional CDI ignition could not ignite mixtures leaner than φ = 0.6. Also, faster combustion times and shorter ignition delays were observed in the case of laser ignition. Through scans performed for minimum required laser energies (MRE), it was noted that the measured values were substantially higher than those reported elsewhere. However, the trends of these values indicate that a laser ignition system designed for φ = 0.65 will successfully operate under all other equivalence ratios of a typical lean-burn engine.

Laser Ignition of Methane-Air Mixtures at High Pressures and Diagnostics

2003 ◽  
Author(s):  
Herbert Kopecek ◽  
Soren Charareh ◽  
Max Lackner ◽  
Christian Forsich ◽  
Franz Winter ◽  
...  
Keyword(s):  
Natural Gas ◽  
Nd:Yag Laser ◽  
High Pressures ◽  
Laser Energy ◽  
Spectroscopic Technique ◽  
Laser Ignition ◽  
Pulsed Nd:Yag Laser ◽  
Natural Gas Engines ◽  
Spark Plug ◽  
Induced Ignition

Methane-air mixtures at high fill pressures up to 30 bar and high temperatures up to 200 °C were ignited in a high pressure chamber with automated fill control by a 5 ns pulsed Nd:YAG laser at 1064 nm wavelength. Both, the minimum input laser pulse energy for ignition and the transmitted fraction of energy through the generated plasma were measured as a function of the air/fuel-equivalence ratio (λ). The lean side ignition limit of methane-air mixtures was found to be λ = 2.4. However, only λ < 2.2 seems to be practically usable. As a comparison, the limit for conventional spark plug ignition of commercial natural gas engines is λ = 1.8. Only with excessive efforts λ = 2.0 can be spark-ignited. The transmitted pulse shape through the laser-generated plasma was determined temporally as well as its dependence on input laser energy and properties of the specific gases interacting. For a first demonstration of the practical applicability of laser ignition, one cylinder of a 1 MW natural gas engine was ignited by a similar 5 ns pulsed Nd:YAG laser at 1064 nm. The engine worked successfully at λ = 1.8 for a first test period of 100 hours without any interruption due to window fouling and other disturbances. Lowest values for NOx emission were achieved at λ = 2.05 (NOx = 0.22 g/KWh). Three parameters obtained from accompanying spectroscopic measurements, namely water absorbance, flame emission and the gas inhomogeneity index have proven to be a powerful tool to judge laser-induced ignition of methane-air mixtures. The following effects were determined by the absorption spectroscopic technique: formation of water in the vicinity of the laser spark (semi-quantitative); characterization of ignition (ignition delay, incomplete ignition, failed ignition); homogeneity of the gas phase in the vicinity of the ignition and the progress of combustion.

Laser shock processing with 20 MW laser pulses delivered by optical fibers

2000 ◽  
Vol 9 (3) ◽  
pp. 235-238 ◽  
Author(s):  
T. Schmidt-Uhlig ◽  
P. Karlitschek ◽  
M. Yoda ◽  
Y. Sano ◽  
G. Marowsky
Keyword(s):  
Optical Fibers ◽  
Laser Pulses ◽  
Laser Shock ◽  
Laser Shock Processing ◽  
Shock Processing

Low Emissions Class 8 Heavy-Duty On-Highway Natural Gas and Gasoline Engine

2004 ◽  
Author(s):  
James P. Chiu ◽  
James Wegrzyn ◽  
Kenneth E. Murphy
Keyword(s):  
Natural Gas ◽  
Gasoline Engine ◽  
Heavy Duty
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