Effect of spark timing on laser ignition and spark ignition modes in a hydrogen enriched compressed natural gas fuelled engine

Fuel ◽  
2020 ◽  
Vol 276 ◽  
pp. 118071
Author(s):  
Rajesh Kumar Prasad ◽  
Nirendra Mustafi ◽  
Avinash Kumar Agarwal
Keyword(s):  
Natural Gas ◽  
Spark Ignition ◽  
Laser Ignition ◽  
Compressed Natural Gas ◽  
Spark Timing

Experimental Investigation of a Heavy-Duty Compression-Ignition Engine Retrofitted to Natural Gas Spark-Ignition Operation

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Jinlong Liu ◽  
Hemanth Kumar Bommisetty ◽  
Cosmin Emil Dumitrescu
Keyword(s):  
Natural Gas ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Compression Ignition ◽  
Heavy Duty ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Cycle Variation ◽  
Spark Timing ◽  
Ci Engines

Heavy-duty compression-ignition (CI) engines converted to natural gas (NG) operation can reduce the dependence on petroleum-based fuels and curtail greenhouse gas emissions. Such an engine was converted to premixed NG spark-ignition (SI) operation through the addition of a gas injector in the intake manifold and of a spark plug in place of the diesel injector. Engine performance and combustion characteristics were investigated at several lean-burn operating conditions that changed fuel composition, spark timing, equivalence ratio, and engine speed. While the engine operation was stable, the reentrant bowl-in-piston (a characteristic of a CI engine) influenced the combustion event such as producing a significant late combustion, particularly for advanced spark timing. This was due to an important fraction of the fuel burning late in the squish region, which affected the end of combustion, the combustion duration, and the cycle-to-cycle variation. However, the lower cycle-to-cycle variation, stable combustion event, and the lack of knocking suggest a successful conversion of conventional diesel engines to NG SI operation using the approach described here.

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.

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.

Effect of focal size on the laser ignition of compressed natural gas–air mixture

2014 ◽  
Vol 58 ◽  
pp. 67-79 ◽  
Author(s):  
Dhananjay Kumar Srivastava ◽  
Ernst Wintner ◽  
Avinash Kumar Agarwal
Keyword(s):  
Natural Gas ◽  
Laser Ignition ◽  
Compressed Natural Gas

Conversion of a Heavy-Duty Diesel Engine to Natural-Gas Spark-Ignition Operation: Test Bench Development

2019 ◽  
Author(s):  
Jinlong Liu ◽  
Cosmin E. Dumitrescu ◽  
Hemanth Bommisetty ◽  
Christopher Ulishney
Keyword(s):  
Natural Gas ◽  
Compression Ratio ◽  
Diesel Engines ◽  
Pressure Rise ◽  
Spark Ignition ◽  
High Energy ◽  
Combustible Mixture ◽  
Stable Operation ◽  
Spark Timing ◽  
Heavy Duty Diesel

Abstract Partial conversion of the large inventory of diesel engines to natural gas (NG) spark-ignition (SI) will reduce U.S. dependence on imported petroleum and enhance national energy security. This paper describes the methodology used to retrofit such an engine as well as the experimental setup used to investigate and optimize the conversion, including engine modifications, coupled dynamometer, engine control, and data acquisition system. Low-pressure gas injectors placed upstream of the intake valve produced a homogeneous combustible mixture inside the cylinder. The final setup was verified via experiments that changed the equivalence ratio from 0.7 to 1.0 at 900 rpm, using methane as a natural gas surrogate. The results showed that despite the higher compression ratio (which increased in-cylinder pressure and temperature at spark timing compared to conventional SI engines), a high-energy spark plug was necessary to produce robust and repeatable ignition. In addition, the moderate compression ratio of the converted engine (13.3) resulted in knock-free operation at all equivalence ratios. Finally, the reliable and stable operation at the investigated conditions (COVIMEP &lt; 1.5%) and low rate of pressure rise (&lt; 3 bar/deg CA) support this solution for converting diesel engines to NG SI operation, at least for the conditions investigated here. The trend of engine-out emissions agreed well with existing studies, which also validated the design of the test cell for optimizing engine efficiency and sampling emissions.

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.

Sign in / Sign up

Export Citation Format

Share Document