Modeling the Effect of Natural Gas Composition on Ignition Delay Under Compression Ignition Conditions

1997 ◽  
Author(s):  
Apoorva Agarwal ◽  
Dennis N. Assanis
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Compression Ignition ◽  
Gas Composition

Numerical evaluation of the effect of methane number on natural gas and diesel dual-fuel combustion

2018 ◽  
Vol 20 (4) ◽  
pp. 405-423 ◽  
Author(s):  
Zhenkuo Wu ◽  
Christopher J Rutland ◽  
Zhiyu Han
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Fuel Combustion ◽  
Dual Fuel ◽  
Compression Ignition ◽  
Gas Composition ◽  
Reactivity Controlled Compression Ignition ◽  
Dual Fuel Combustion ◽  
Compression Ignition Combustion ◽  
Methane Number

Natural gas and diesel dual-fuel combustion is a promising technology for efficiently utilizing natural gas in a compression ignition engine. Natural gas composition varies depending on the geographical source, which affects engine performance. The methane number is an indicator of natural gas fuel quality to assess the variation in composition. In this study, the influences of methane number on natural gas/diesel dual-fuel combustion were numerically examined using computational fluid dynamic simulations. The differences between natural gases with the same methane number but different components were also compared. Two dual-fuel combustion strategies, diesel pilot ignition, and reactivity controlled compression ignition were evaluated. The results show that for both diesel pilot ignition and reactivity controlled compression ignition, the ignition delay increases and the combustion duration decreases as the methane number is increased. The retarded trend of ignition of reactivity controlled compression ignition is more significant than that of diesel pilot ignition, while the decreased trend in combustion duration is less significant. To understand this trend, a chemical kinetics study of ignition delay characteristic of natural gas and n-heptane mixture was conducted. The result reveals that introducing ethane, propane, or an ethane–propane mixture into pure methane shortens the ignition delay in the entire temperature range. However, for the methane and n-heptane mixture, adding ethane, or propane, or an ethane–propane mixture shortens the ignition delay in the high temperature range, while increases the ignition delay in the low temperature range. These observations in combination with the analysis of air–fuel mixture formation and combustion provide the evidence to interpret the different ignition and combustion behaviors between diesel pilot ignition and reactivity controlled compression ignition combustion. In addition, a temperature A-factor sensitivity study was carried out to explain the result of the chemical kinetics study. Furthermore, the responses of emissions to methane number were also investigated. The results show that for diesel pilot ignition, the hydrocarbon and carbon monoxide emissions decrease with the decreased methane number. However, for reactivity controlled compression ignition, the variations of hydrocarbon and carbon monoxide emissions with the methane number are not so obvious as for diesel pilot ignition combustion. For both diesel pilot ignition and reactivity controlled compression ignition combustion, the nitrogen oxides emissions show a strong dependence on combustion phasing rather than natural gas composition. Overall, to control diesel pilot ignition combustion, the methane number should be considered together with other parameters. However, attention should be paid to other control parameters for the reactivity controlled compression ignition combustion. The engine performance of reactivity controlled compression ignition is not sensitive to the variation of natural gas composition, so it can adapt to the natural gas from different sources.

scholarly journals Effects of natural gas composition on ignition delay under diesel conditions

1994 ◽  
Vol 99 (2) ◽  
pp. 192-200 ◽  
Author(s):  
J.D. Naber ◽  
D.L. Siebers ◽  
S.S. Di Julio ◽  
C.K. Westbrook
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Gas Composition

Study of Assisted Compression Ignition in a Direct Injected Natural Gas Engine

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Ivan M. Gogolev ◽  
James S. Wallace
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Equivalence Ratio ◽  
Direct Injection ◽  
Air Entrainment ◽  
Source Analysis ◽  
Compression Ignition ◽  
Glow Plug ◽  
Injection Duration ◽  
Intake Pressure

Natural gas direct injection (DI) and glow plug ignition assist technologies were implemented in a single-cylinder, compression-ignition optical research engine. Initial experiments studied the effects of injector and glow plug shield geometry on ignition quality. Injector and shield geometric effects were found to be significant, with only two of 20 tested geometric combinations resulting in reproducible ignition. Of the two successful combinations, the combination with 0 deg injector angle and 60 deg shield angle was found to result in shorter ignition delay and was selected for further testing. Further experiments explored the effects of the overall equivalence ratio (controlled by injection duration) and intake pressure on ignition delay and combustion performance. Ignition delay was measured to be in the range of 1.6–2.0 ms. Equivalence ratio was found to have little to no effect on the ignition delay. Higher intake pressure was shown to increase ignition delay due to the effect of swirl momentum on fuel jet development, air entrainment, and jet deflection away from optimal contact with the glow plug ignition source. Analysis of combustion was carried out by examination of the rate of heat release (ROHR) profiles. ROHR profiles were consistent with two distinct modes of combustion: premixed mode at all test conditions, and a mixing-controlled mode that only appeared at higher equivalence ratios following premixed combustion.

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.

scholarly journals Research on the Compression Ignition and Combustion of Natural Gas and Its Reformed Gas

2005 ◽  
Vol 71 (705) ◽  
pp. 1465-1474 ◽  
Author(s):  
Susumu SATO ◽  
Yudai YAMASAKI ◽  
Hideo KAWAMURA ◽  
Norimasa IIDA
Keyword(s):  
Natural Gas ◽  
Compression Ignition ◽  
Ignition And Combustion

Compression ignition of directly injected natural gas with entrained diesel

2010 ◽  
Vol 11 (3) ◽  
pp. 207-218 ◽  
Author(s):  
C A Laforet ◽  
B S Brown ◽  
S N Rogak ◽  
S R Munshi
Keyword(s):  
Natural Gas ◽  
Compression Ignition
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