Experimental Study of the Effect of Intake Oxygen Concentration on Engine Combustion Process and Hydrocarbon Emissions with N-Butanol-Diesel Blended Fuel

This paper summarizes a study based on a modified, light, single-cylinder diesel engine and the effects of the physicochemical properties for n-butanol-diesel blended fuel on the combustion process and hydrocarbon (HC) emissions in the intake at a medium speed and moderate load in, an oxygen-rich environment (Coxy = 20.9–16%), an oxygen-medium environment (Coxy = 16–12%), and an oxygen-poor environment (Coxy = 12–9%). The results show that the ignition delay period is the main factor affecting the combustion process and it has a decisive influence on HC emissions. In an oxygen-medium environment, combustion duration affected by the cetane number is the main reason for the difference in HC emissions between neat diesel fuel (B00) and diesel/n-butanol blended fuel (B20), and its influence increases as the intake oxygen concentration decreases. In an oxygen-poor environment, in-cylinder combustion temperature affected by the latent heat of vaporization is the main reason for the difference in HC emissions between B00 and B20 fuels, and its influence increases as the intake oxygen concentration decreases. By comparing B20 fuel with diesel/n-butanol/2-ethylhexyl nitrate blended fuel (B20 + EHN), the difference in the ignition delay period caused by the difference in the cetane number is the main reason for the difference in HC emissions between B20 and B20 + EHN fuels in oxygen-poor environment, and the effect of this influencing factor gradually increases as the intake oxygen concentration decreases.

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Effects of Fuel Overpenetration and Overmixing During Ignition-Delay Period on Hydrocarbon Emissions From a Small Open-Chamber Diesel Engine

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.3240142 ◽

1988 ◽

Vol 110 (3) ◽

pp. 453-461 ◽

Cited By ~ 11

Author(s):

T.-W. Kuo ◽

K.-J. Wu ◽

S. Henningsen

Keyword(s):

Diesel Engine ◽

Ignition Delay ◽

Fuel Injection ◽

Swirling Flow ◽

Delay Period ◽

Injection Velocity ◽

Spray Penetration ◽

Hc Emissions ◽

Start Of Combustion ◽

Ignition Delay Period

A quasi-steady gas-jet model was applied to examine the spray trajectory in swirling flow during the ignition-delay period in an open-chamber diesel engine timed to start combustion at top dead center. Spray penetration, deflection, and the fractions of too-lean-mixed, burnable, and overpenetrated fuel at the start of combustion were calculated by employing the measured ignition delay and mean fuel-injection velocity. The calculated parameters were applied to correlate the measured exhaust hydrocarbon (HC) emissions. The engine parameters examined were bowl geometry, compression ratio, overall air-fuel ratio, and speed. Both the ignition delay and the relative spray-penetration parameter, defined as the ratio of the spray-penetration distances at the moments of start of combustion and wall impingement, gave good correlations for some of the engine parameters examined but could not explain all the measured trends. However, good correlation of the measured exhaust HC emissions was obtained by using the calculated too-lean-mixed and overpenetrated fuel fractions at the start of combustion. Correlation of the overpenetrated fuel with the measured HC indicated that approximately 2 percent of the fuel mass that overpenetrated before start of combustion emitted from the engine as unburned HC. This could account for 0 to 65 percent of the total HC emission from this engine. Additionally, it was found that the too-lean-mixed fuel could contribute 10 to 30 percent of the total HC emission, as found in a previous study on a somewhat similar engine. The remaining HC emission is caused by other sources such as bulk quenching.

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Effect of Inlet Air Temperature on Auto-Ignition of Fuels With Different Cetane Number and Volatility

ASME 2011 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2011-60141 ◽

2011 ◽

Cited By ~ 3

Author(s):

Chandrasekharan Jayakumar ◽

Ziliang Zheng ◽

Umashankar M. Joshi ◽

Walter Bryzik ◽

Naeim A. Henein ◽

...

Keyword(s):

Air Temperature ◽

Ignition Delay ◽

Fuel Injection ◽

Cetane Number ◽

Delay Period ◽

Inlet Temperature ◽

Ignition Process ◽

Ultra Low Sulfur Diesel ◽

Auto Ignition ◽

Ignition Delay Period

This paper investigates the effect of air inlet temperature on the auto-ignition of fuels that have different CN and volatility in a single cylinder diesel engine. The inlet air temperature is varied over a range of 30°C to 110°C. The fuels used are ultra-low-sulfur-diesel (ULSD), JP-8 (two blends with CN 44.1 & 31) and F-T SPK. Detailed analysis is made of the rate of heat release during the ignition delay period, to determine the effect of fuel volatility and CN on the auto-ignition process. A STAR-CD CFD model is applied to simulate the spray behavior and gain more insight into the processes that immediately follow the fuel injection including evaporation, start of exothermic reactions and the early stages of combustion. The mole fractions of different species are determined during the ignition delay period and their contribution in the auto-ignition process is examined. Arrhenius plots are developed to calculate the global activation energy for the auto-ignition reactions of these fuels. Correlations are developed for the ID and the mean air temperature and pressure.

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Effect of Pilot Injection on Mixture Formation, Ignition Process and Flame Development in Diesel Combustion

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.390.327 ◽

2013 ◽

Vol 390 ◽

pp. 327-332 ◽

Cited By ~ 1

Author(s):

Amir Khalid ◽

M. Jaat ◽

Izzuddin Zaman ◽

B. Manshoor ◽

Mas Fawzi

Keyword(s):

Ignition Delay ◽

High Speed ◽

Combustion Process ◽

Video Camera ◽

Delay Period ◽

Ignition Process ◽

Pilot Injection ◽

Mixture Formation ◽

Digital Video Camera ◽

Ignition Delay Period

The alternative combustion strategies with systematic control of mixture formation have provided new opportunities and considerable improvement in the combustion process and response to meet the stringent emissions standards. Purpose of this research is to investigate the influences of pilot injection on the fuel-air premixing especially during ignition delay period. During this period, the interaction between fuel spray and surrounding gas prior to ignition which linked to the improvement of mixture formation, ignition process and initial heat recovery thus predominantly influences the combustion process and exhaust emissions. This study investigates the effects of pilot injection using a rapid compression machine together with the schlieren photography and direct photography methods. The detail behavior of mixture formation during ignition delay period was investigated using the schlieren photography system with a high speed digital video camera. This method can capture spray evaporation, spray interference and mixture formation clearly with real images. Ignition process and flame development were investigated by direct photography method using a light sensitive high-speed color digital video camera. Pilot injection promotes mixture formation during ignition delay period and slower oxidation reaction and thus leads to earlier rise and lower peak heat release rate.

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Experimental investigations to predict optimistic biodiesel(s) and its optimistic operating conditions by varying ignition delay period and fuel spray pressures for lower emissions and better performance

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406220917693 ◽

2020 ◽

Vol 234 (19) ◽

pp. 3890-3902

Author(s):

Vishal V Patil ◽

Ranjit S Patil

Keyword(s):

Methyl Ester ◽

Ignition Delay ◽

Seed Oil ◽

Delay Period ◽

Operating Conditions ◽

Experimental Investigations ◽

Rubber Seed Oil ◽

Rubber Seed ◽

Neem Seed Oil ◽

Ignition Delay Period

In this study, different characteristics of sustainable renewable biodiesels (those have a high potential of their production worldwide and in India) were compared with the characteristics of neat diesel to determine optimistic biodiesel for the diesel engine at 250 bar spray pressure. Optimistic fuel gives a comparatively lower level of emissions and better performance than other selected fuels in the study. Rubber seed oil methyl ester was investigated as an optimistic fuel among the other selected fuels such as sunflower oil methyl ester, neem seed oil methyl ester, and neat diesel. To enhance the performance characteristics and to further decrease the level of emission characteristics of fuel ROME, further experiments were conducted at higher spray (injection) pressures of 500 bar, 625 bar, and 750 bar with varying ignition delay period via varying its spray timings such as 8°, 13°, 18°, 23°, 28°, and 33° before top dead center. Spray pressure 250 bar at 23° before top dead center was investigated as an optimistic operating condition where fuel rubber seed oil methyl ester gives negligible hydrocarbon emissions (0.019 g/kW h) while its nitrogen oxide (NOX) emissions were about 70% lesser than those observed with neat diesel, respectively.

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