scholarly journals Towards the Development of a Conceptual Model for Pre-chamber Spark-Ignition High Efficiency Natural Gas Engines.

2020 ◽  
Author(s):  
Rajavasanth Rajasegar ◽  
Yoichi Niki ◽  
Garcia Jose Maria ◽  
Zheming Li ◽  
Mark Musculus
Keyword(s):  
Natural Gas ◽  
Conceptual Model ◽  
High Efficiency ◽  
Spark Ignition ◽  
Natural Gas Engines

Assessment of Turbulent Combustion Models for Simulating Pre-Chamber Ignition in a Natural Gas Engine

2021 ◽  
Author(s):  
Joohan Kim ◽  
Riccardo Scarcelli ◽  
Sibendu Som ◽  
Ashish Shah ◽  
Munidhar Biruduganti ◽  
...  
Keyword(s):  
Natural Gas ◽  
Turbulent Combustion ◽  
High Efficiency ◽  
Turbulent Flame ◽  
Spark Ignition ◽  
Cylinder Wall ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Combustion Models ◽  
Combustion Processes

Abstract Lean combustion in an internal combustion engine is a promising strategy to increase thermal efficiency by leveraging a more favorable specific heat ratio of the fresh mixture and simultaneously suppressing the heat losses to the cylinder wall. However, unstable ignition events and slow flame propagation at fuel-lean condition lead to high cycle-to-cycle variability and hence limit the high-efficiency engine operating range. Pre-chamber ignition is considered an effective concept to extend the lean operating limit, by providing spatially distributed ignition with multiple turbulent flame-jets and enabling faster combustion rate compared to the conventional spark ignition approach. From a numerical modeling perspective, to date, still the science base and available simulation tools are inadequate for understanding and predicting the combustion processes in pre-chamber ignited engines. In this paper, conceptually different RANS combustion models widely adopted in the engine modeling community were used to simulate the ignition and combustion processes in a medium-duty natural gas engine with a pre-chamber spark-ignition system. A flamelet-based turbulent combustion model, i.e., G-equation, and a multi-zone well-stirred reactor model were employed for the multi-dimensional study. Simulation results were compared with experimental data in terms of in-cylinder pressure and heat release rate. Finally, the analysis of the performance of the two models is carried out to highlight the strengths and limitations of the two formulations respectively.

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.

High-Efficiency and Clean Combustion Natural Gas Engines for Vehicles

2019 ◽  
Vol 2 (4) ◽  
pp. 284-304 ◽  
Author(s):  
Fubai Li ◽  
Zhi Wang ◽  
Yunfei Wang ◽  
Boyuan Wang
Keyword(s):  
Natural Gas ◽  
High Efficiency ◽  
Natural Gas Engines ◽  
Clean Combustion

Assessment of Turbulent Combustion Models for Simulating Pre-Chamber Ignition in a Natural Gas Engine

2019 ◽  
Author(s):  
Joohan Kim ◽  
Riccardo Scarcelli ◽  
Sibendu Som ◽  
Ashish Shah ◽  
Munidhar S. Biruduganti ◽  
...  
Keyword(s):  
Natural Gas ◽  
Turbulent Combustion ◽  
High Efficiency ◽  
Turbulent Flame ◽  
Spark Ignition ◽  
Cylinder Wall ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Combustion Models ◽  
Combustion Processes

Abstract Lean combustion in an internal combustion engine is a promising strategy to increase thermal efficiency by leveraging a more favorable specific heat ratio of the fresh mixture and simultaneously suppressing the heat losses to the cylinder wall. However, unstable ignition events and slow flame propagation at fuel-lean condition lead to high cycle-to-cycle variability and hence limit the high-efficiency engine operating range. Pre-chamber ignition is considered an effective concept to extend the lean operating limit, by providing spatially distributed ignition with multiple turbulent flame-jets and enabling faster combustion rate compared to the conventional spark ignition approach. From a numerical modeling perspective, to date, still the science base and available simulation tools are inadequate for understanding and predicting the combustion processes in pre-chamber ignited engines. In this paper, conceptually different RANS combustion models widely adopted in the engine modeling community were used to simulate the ignition and combustion processes in a medium-duty natural gas engine with a pre-chamber spark-ignition system. A flamelet-based turbulent combustion model, i.e., G-equation, and a multi-zone well-stirred reactor model were employed for the multi-dimensional study. Simulation results were compared with experimental data in terms of in-cylinder pressure and heat release rate. Finally, the analysis of the performance of the two models is carried out to highlight the strengths and limitations of the two formulations respectively.

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.

Evaluation of a Lean-Burn Natural Gas Engine Operating on Variable Methane Number Fuel

2011 ◽  
Author(s):  
Cory J. Kreutzer ◽  
Daniel B. Olsen ◽  
Robin J. Bremmer
Keyword(s):  
Natural Gas ◽  
High Efficiency ◽  
Engine Performance ◽  
Combustion Stability ◽  
Lean Burn ◽  
Natural Gas Engines ◽  
Spark Timing ◽  
Gas Compression ◽  
Fuel Blending ◽  
Methane Number

Wellhead gas from which pipeline natural gas originates has significant variability in composition due to natural variations in deposits. Gas quality is influenced by relative concentrations of both inert and hydrocarbon species. Gas compression engines utilizing wellhead gas as a fuel source often require significant installation time and adjustment of stock configuration due to fuel compositions that vary with time and location. Lean burn natural gas engines are chosen as wellhead compression engines for high efficiency and low emissions while minimizing the effect of variable gas composition. Ideal engine conditions are maintained by operating within the knock and misfire limits of the engine. Additional data is needed to find engine operational limitations. In this work, experimental data was collected on a Cummins GTA8.3SLB engine operating on variable methane number fuel under closed-loop equivalence ratio control. A fuel blending system was used to vary methane number to simulate wellhead compositions. NOx and CO emissions were found to increase with decreasing methane number while combustion stability remained constant. In addition, the effects of carbon dioxide and nitrogen diluents in the fuel were investigated. When diluents were present in the fuel, engine performance could be maintained by spark timing advance.

Spark ignition natural gas engines—A review

2007 ◽  
Vol 48 (2) ◽  
pp. 608-618 ◽  
Author(s):  
Haeng Muk Cho ◽  
Bang-Quan He
Keyword(s):  
Natural Gas ◽  
Spark Ignition ◽  
Natural Gas Engines

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 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 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.

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