scholarly journals Prechamber Equipped Laser Ignition for Improved Performance in Natural Gas Engines

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Bader Almansour ◽  
Subith Vasu ◽  
Sreenath B. Gupta ◽  
Qing Wang ◽  
Robert Van Leeuwen ◽  
...  
Keyword(s):  
Natural Gas ◽  
Soot Formation ◽  
Single Point ◽  
Spark Ignition ◽  
Laser Ignition ◽  
Efficiency Gain ◽  
Lean Burn ◽  
Single Cylinder ◽  
Natural Gas Engines ◽  
Improved Performance

Lean-burn operation of stationary natural gas engines offers lower NOx emissions and improved efficiency. A proven pathway to extend lean-burn operation has been to use laser ignition (LI) instead of standard spark ignition (SI). However, under lean conditions, flame speed reduces, thereby offsetting any efficiency gains resulting from the higher ratio of specific heats, γ. The reduced flame speeds, in turn, can be compensated with the use of a prechamber to result in volumetric ignition and thereby lead to faster combustion. In this study, the optimal geometry of PCLI was identified through several tests in a single-cylinder engine as a compromise between autoignition, NOx, and soot formation within the prechamber. Subsequently, tests were conducted in a single-cylinder natural gas engine comparing the performance of three ignition systems: standard electrical spark ignition (SI), single-point laser ignition (LI), and PCLI. Out of the three, the performance of PCLI was far superior compared to the other two. Efficiency gain of 2.1% points could be achieved while complying with EPA regulation (BSNOx < 1.34 kWh) and the industry standard for ignition stability (coefficient of variation of integrated mean effective pressure (COV_IMEP) < 5%). Test results and data analysis are presented identifying the combustion mechanisms leading to the improved performance.

Laser Ignition of Natural Gas Engines Using Fiber Delivery

2005 ◽  
Author(s):  
Azer P. Yalin ◽  
Morgan W. Defoort ◽  
Sachin Joshi ◽  
Daniel Olsen ◽  
Bryan Willson ◽  
...  
Keyword(s):  
Natural Gas ◽  
Past Research ◽  
Spark Ignition ◽  
Laser Source ◽  
Laser Ignition ◽  
Ignition System ◽  
Gas Engine ◽  
Natural Gas Engines ◽  
Natural Gas Engine ◽  
Design Concepts

A practical impediment to implementation of laser ignition systems has been the open-path beam delivery used in past research. In this contribution, we present the development and implementation of a fiber-optically delivery laser spark ignition system. To our knowledge, the work represents the first demonstration of fiber coupled laser ignition (using a remote laser source) of a natural gas engine. A Nd:YAG laser is used as the energy source and a coated hollow fiber is used for beam energy delivery. The system was implemented on a single-cylinder of a Waukesha VGF 18 turbo charged natural gas engine and yielded consistent and reliable ignition. In addition to presenting the design and testing of the fiber delivered laser ignition system, we present initial design concepts for a multiplexer to ignite multiple cylinders using a single laser source, and integrated optical diagnostic approaches to monitor the spark ignition and combustion performance.

Laser Spark Ignition: Laser Development and Engine Testing

2004 ◽  
Author(s):  
Michael H. McMillian ◽  
Steven D. Woodruff ◽  
Steven W. Richardson ◽  
Dustin L. McIntyre
Keyword(s):  
Natural Gas ◽  
Laser System ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Lean Burn ◽  
Engine Operation ◽  
Natural Gas Engines ◽  
Laser Spark ◽  
Engine Testing ◽  
Laser Spark Ignition

Evermore demanding market and legislative pressures require stationary lean-burn natural gas engines to operate at higher efficiencies and reduced levels of emissions. Higher in-cylinder pressures and leaner air/fuel ratios are required in order to meet these demands. Contemporary ignition systems, more specifically spark plug performance and durability, suffer as a result of the increase in spark energy required to maintain suitable engine operation under these conditions. This paper presents a discussion of the need for an improved ignition source for advanced stationary natural gas engines and introduces laser spark ignition as a potential solution to that need. Recent laser spark ignition engine testing with natural gas fuel including NOx mapping is discussed. A prototype laser system in constructed and tested and the results are discussed and solutions provided for improving the laser system output pulse energy and pulse characteristics.

Laser-Spark Ignition Testing in a Natural Gas-Fueled Single-Cylinder Engine

2004 ◽  
Author(s):  
Michael McMillian ◽  
Steven Richardson ◽  
Steven D. Woodruff ◽  
Dustin McIntyre
Keyword(s):  
Natural Gas ◽  
Spark Ignition ◽  
Single Cylinder ◽  
Single Cylinder Engine ◽  
Laser Spark ◽  
Gas Fueled ◽  
Laser Spark Ignition

Effects of stroke on spark-ignition combustion with gasoline and methanol

2021 ◽  
pp. 146808742110396
Author(s):  
Christian Wouters ◽  
Patrick Burkardt ◽  
Marcus Fischer ◽  
Michael Blomberg ◽  
Stefan Pischinger
Keyword(s):  
Alternative Fuels ◽  
Internal Combustion Engines ◽  
High Efficiency ◽  
Combustion Velocity ◽  
Spark Ignition ◽  
Efficiency Gain ◽  
Lean Burn ◽  
Piston Speed ◽  
Long Stroke ◽  
Stroke Engine

Besides electrification of the powertrain, new synthetic alternative fuels with the potential to be produced from renewable sources come into focus. Methanol is the most elementary liquid synthetic fuel and no novelty for use in internal combustion engines. This article presents pathways to achieve high efficiency spark-ignition methanol combustion on a direct injection spark-ignition single-cylinder research engine with two different stroke-to-bore ratios (1.2 and 1.5) and a constant bore. In addition, two compression ratios (CRs) were investigated on each setup: CR = 10.8 using RON95 E10 gasoline fuel and a higher CR = 15 using neat methanol. In contrast to previous studies of stroke-to-bore ratio influences on SI combustion, this article aims at demonstrating how the advantages of a high stroke-to-bore ratio can be exploited by combining a long-stroke engine with increased compression ratios and methanol. The increased stroke enhances the tumble motion due to a higher piston speed and a larger compression volume which improves the mixture homogenization and combustion velocity. Moreover, the lower surface/volume ratio results in a reduced heat transfer. When using RON95E10 gasoline fuel and CR = 10.8, an efficiency gain of up to 1.6% could be achieved with the long-stroke compared to the short-stroke especially at lower engine loads. With methanol and CR = 15, an efficiency gain of up to 1.6% could be achieved with the long-stroke setup compared to the short-stroke engine. Subsequently, lean burn conditions were experimentally investigated with methanol and CR = 15. The longer stroke allowed the lean burn limit to be extended from λ = 1.9 to λ = 2.0 with an efficiency gain of up to 2.2%. A maximum indicated efficiency of 47.4% could be achieved at λ = 1.9 with methanol on the long-stroke engine with CR = 15.

scholarly journals Parametric Knocking Performance Investigation of Spark Ignition Natural Gas Engines and Dual Fuel Engines

2020 ◽  
Vol 8 (6) ◽  
pp. 459 ◽  
Author(s):  
La Xiang ◽  
Gerasimos Theotokatos ◽  
Haining Cui ◽  
Keda Xu ◽  
Hongkai Ben ◽  
...  
Keyword(s):  
Natural Gas ◽  
Compression Ratio ◽  
Engine Performance ◽  
Spark Ignition ◽  
Combustion Model ◽  
Dual Fuel ◽  
Ignition Timing ◽  
Natural Gas Engines ◽  
Study Results ◽  
Pilot Fuel

Both spark ignition (SI) natural gas engines and compression ignition (CI) dual fuel (DF) engines suffer from knocking when the unburnt mixture ignites spontaneously prior to the flame front arrival. In this study, a parametric investigation is performed on the knocking performance of these two engine types by using the GT-Power software. An SI natural gas engine and a DF engine are modelled by employing a two-zone zero-dimensional combustion model, which uses Wiebe function to determine the combustion rate and provides adequate prediction of the unburnt zone temperature, which is crucial for the knocking prediction. The developed models are validated against experimentally measured parameters and are subsequently used for performing parametric investigations. The derived results are analysed to quantify the effect of the compression ratio, air-fuel equivalence ratio and ignition timing on both engines as well as the effect of pilot fuel energy proportion on the DF engine. The results demonstrate that the compression ratio of the investigated SI and DF engines must be limited to 11 and 16.5, respectively, for avoiding knocking occurrence. The ignition timing for the SI and the DF engines must be controlled after −38°CA and 3°CA, respectively. A higher pilot fuel energy proportion between 5% and 15% results in increasing the knocking tendency and intensity for the DF Engine at high loads. This study results in better insights on the impacts of the investigated engine design and operating settings for natural gas (NG)-fuelled engines, thus it can provide useful support for obtaining the optimal settings targeting a desired combustion behaviour and engine performance while attenuating the knocking tendency.

scholarly journals Emission of Toxic HCN During NO x Removal by Ammonia SCR in the Exhaust of Lean‐Burn Natural Gas Engines

2020 ◽  
Vol 59 (34) ◽  
pp. 14423-14428 ◽  
Author(s):  
Deniz Zengel ◽  
Pirmin Koch ◽  
Bentolhoda Torkashvand ◽  
Jan‐Dierk Grunwaldt ◽  
Maria Casapu ◽  
...  
Keyword(s):  
Natural Gas ◽  
Lean Burn ◽  
Natural Gas Engines

Lean-Burn Characteristics of a Heavy-Duty Diesel Engine Retrofitted to Natural Gas Spark Ignition

2018 ◽  
Author(s):  
Jinlong Liu ◽  
Cosmin E. Dumitrescu
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Combustion Stability ◽  
Fuel Injector ◽  
Heavy Duty ◽  
Lean Burn ◽  
Spark Timing ◽  
Heavy Duty Diesel

Increased utilization of natural-gas (NG) in the transportation sector can decrease the use of petroleum-based fuels and reduce greenhouse-gas emissions. Heavy-duty diesel engines retrofitted to NG spark ignition (SI) can achieve higher efficiencies and low NOx, CO, and HC emissions when operated under lean-burn conditions. To investigate the SI lean-burn combustion phenomena in a bowl-in-piston combustion chamber, a conventional heavy-duty direct-injection CI engine was converted to SI operation by replacing the fuel injector with a spark plug and by fumigating NG in the intake manifold. Steady-state engine experiments and numerical simulations were performed at several operating conditions that changed spark timing, engine speed, and mixture equivalence ratio. Results suggested a two-zone NG combustion inside the diesel-like combustion chamber. More frequent and significant late burn (including double-peak heat release rate) was observed for advanced spark timing. This was due to the chamber geometry affecting the local flame speed, which resulted in a faster and thicker flame in the bowl but a slower and thinner flame in the squish volume. Good combustion stability (COVIMEP < 3 %), moderate rate of pressure rise, and lack of knocking showed promise for heavy-duty CI engines converted to NG SI operation.

Experimental study of combustion strategy for jet ignition on a natural gas engine

2020 ◽  
pp. 146808742097775
Author(s):  
Ziqing Zhao ◽  
Zhi Wang ◽  
Yunliang Qi ◽  
Kaiyuan Cai ◽  
Fubai Li
Keyword(s):  
Experimental Study ◽  
Natural Gas ◽  
Efficient Points ◽  
Lean Burn ◽  
Gas Engine ◽  
Absolute Value ◽  
Natural Gas Engines ◽  
Natural Gas Engine ◽  
Excess Air ◽  
Lean Limit

To explore a suitable combustion strategy for natural gas engines using jet ignition, lean burn with air dilution, stoichiometric burn with EGR dilution and lean burn with EGR dilution were investigated in a single-cylinder natural gas engine, and the performances of two kinds of jet ignition technology, passive jet ignition (PJI) and active jet ignition (AJI), were compared. In the study of lean burn with air dilution strategy, the results showed that AJI could extend the lean limit of excess air ratio (λ) to 2.1, which was significantly higher than PJI’s 1.6. In addition, the highest indicated thermal efficiency (ITE) of AJI was shown 2% (in absolute value) more than that of PJI. Although a decrease of NOx emission was observed with increasing λ in the air dilution strategy, THC and CO emissions increased. Stoichiometric burn with EGR was proved to be less effective, which can only be applied in a limited operation range and had less flexibility. However, in contrast to the strategy of stoichiometric burn with EGR, the strategy of lean burn with EGR showed a much better applicability, and the highest ITE could achieve 45%, which was even higher than that of lean burn with air dilution. Compared with the most efficient points of lean burn with pure air dilution, the lean burn with EGR dilution could reduce 78% THC under IMEP = 1.2 MPa and 12% CO under IMEP = 0.4 MPa. From an overall view of the combustion and emission performances under both low and high loads, the optimum λ would be from 1.4 to 1.6 for the strategy of lean burn with EGR dilution.

Sign in / Sign up

Export Citation Format

Share Document