Comparison of Different Gasoline Alternative Fuels in Terms of Laminar Burning Velocity at Increased Gas Temperatures and Exhaust Gas Recirculation Rates

Diesel engines have been widely used as a mode of public transport and private vehicles because of several advantages compared to gasoline engines including greater power, fuel economy, high reliability and durability of the engine and lower CO emissions. However, diesel engines release more NOx and soot emissions into the atmosphere. This is a serious problem with the strict regulations regarding exhaust emissions. Besides problems of depletion of fossil fuel reserves require various parties to seek alternative fuels derived diesel fuel. Therefore, this work is intended to reduce soot emissions by adding LPM (low purity methanol) or wet methanol and HPM (high purity methanol) into a mixture of jatropha and diesel fuels. From this research, it is also desirable to observe the effect of methanol additive to the specific fuel consumption. Experiment method was conducted to obtain the correlation between the percentage of methanol to a brake specific fuel consumption (BSFC) and soot emissions. Methanol (LPM and HPM) was varied in the range of 5 to 15% by volume. Jatropha is in the range of 10% to 30%. The rate of EGR (exhaust gas recirculation) expressed by OEV (opening EGR valve) was varied at the opening of 0 to 100%. Engine load was varied from 25 to 100% at intervals of 25%. The engine speed was kept constant of 2000 rpm. The results show that the use of fuel mixture increases evenly BSFC of 5.2% and soot emissions of 65%. Keywords: LPM and HPM, BSFC, soot emissions, jatropha, cold EGR and diesel engine Abstrak Mesin diesel telah banyak digunakan sebagai moda transportasi umum dan kendaraan pribadi oleh karena beberapa kelebihannya dibandingkan dengan mesin bensin diantaranya daya yang lebih besar, hemat bahan bakar, kehandalan dan ketahanan mesin yang tinggi (high realibility and durability), dan emisi CO yang lebih rendah. Akan tetapi mesin diesel melepaskan lebih banyak emisi NOx dan jelaga ke atmosfir. Hal ini menjadi permasalahan serius dengan semakin ketatnya regulasi menyangkut emisi gas buang. Selain itu permasalahan menipisnya cadangan bahan bakar fosil menuntut berbagai pihak untuk mencari bahan bakar alternatif pengganti solar. Oleh karena itu, penelitian ini bermaksud untuk mereduksi emisi jelaga dengan menambahkan LPM (low purity methanol) atau wet methanol dan HPM (high purity methanol)kedalam campuran bahan bakar jatropha dan solar. Dari penelitian ini juga diinginkan untuk mengamati pengaruh aditif metanol terhadap konsumsi bahan bakar spesifik. Metode eksperimen dilakukan untuk mendapatkan keterkaitan antara prosentase metanol terhadap brake specific fuel consumption (BSFC)dan emisi jelaga. Metanol (LPM dan HPM) divariasikan pada rentang 5% sampai 15%. Jatropha adalah pada rentang 10% sampai 30%. Laju EGR (exhaust gas recirculation) yang dinyatakan oleh OEV (opening EGR valve) divariasikan pada bukaan 0% sampai 100%. Beban mesin divariasikan dari 25% sampai 100% dengan interval 25%. Putaran mesin dipertahankan konstan 2000 rpm. Hasil-hasil penelitian menunjukkan bahwa penggunaan bahan bakar campuran rata-rata meningkatkan BSFC 5,2% dan menurunkan emisi jelaga sampai 65%.

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Prediction of Flame Burning Velocity at Early Flame Development Time With High Exhaust Gas Recirculation and Spark Advance

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4035849 ◽

2017 ◽

Vol 139 (8) ◽

Cited By ~ 5

Author(s):

H. Lian ◽

J. B. Martz ◽

B. P. Maldonado ◽

A. G. Stefanopoulou ◽

K. Zaseck ◽

...

Keyword(s):

Laminar Flame ◽

Burning Velocity ◽

Maximum Level ◽

Exhaust Gas Recirculation ◽

Operating Conditions ◽

Exhaust Gas ◽

Flame Velocity ◽

Flame Development ◽

Gas Recirculation ◽

Averaged Model

Diluting spark-ignited (SI) stoichiometric combustion engines with excess residual gas improves thermal efficiency and allows the spark to be advanced toward maximum brake torque (MBT) timing. However, flame propagation rates decrease and misfires can occur at high exhaust gas recirculation (EGR) conditions and advanced spark, limiting the maximum level of charge dilution and its benefits. The misfire limits are often determined for a specific engine from extensive experiments covering a large range of speed, torque, and actuator settings. To extend the benefits of dilute combustion while at the misfire limit, it is essential to define a parameterizable, physics-based model capable of predicting the misfire limits, with cycle to cycle varied flame burning velocity as operating conditions change based on the driver demand. A cycle-averaged model is the first step in this process. The current work describes a model of cycle-averaged laminar flame burning velocity within the early flame development period of 0–3% mass fraction burned. A flame curvature correction method is used to account for both the effect of flame stretch and ignition characteristics, in a variable volume engine system. Comparison of the predicted and the measured flame velocity was performed using a spark plug with fiber optical access. The comparison at a small set of spark and EGR settings at fixed load and speed, shows an agreement within 30% of uncertainty, while 20% uncertainty equals ± one standard deviation over 2000 cycles.

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Exhaust Gas Recirculation at Elevated Pressure Using a FLOX® Combustor

Volume 4A: Combustion, Fuels and Emissions ◽

10.1115/gt2017-64227 ◽

2017 ◽

Author(s):

Peter Kutne ◽

Judith Richter ◽

James D. Gounder ◽

Clemens Naumann ◽

Wolfgang Meier

Keyword(s):

Power Plants ◽

Alternative Fuels ◽

Combustion Process ◽

Co2 Concentration ◽

Exhaust Gas Recirculation ◽

Elevated Pressure ◽

Flame Stabilization ◽

Exhaust Gas ◽

Capture Process ◽

Gas Recirculation

To reduce CO2 emissions from the combustion of fossil and alternative fuels, carbon capture technologies present a promising approach. But the efficiency of the capture process depends on the CO2 concentration in the exhaust gas which is relatively low for gas turbine power plants. Exhaust gas recirculation (EGR) is a promising approach to increase the CO2 concentration in the exhaust gas stream and thus reduce the energy losses. In this study a FLOX® combustor was used to investigate the influence of EGR on the combustion process of natural gas at elevated pressure. The combustor stabilizes the flame without use of swirl, by creating a strong recirculation through high momentum injection of the fresh gas into the combustion chamber. This enables the establishment of a distributed combustion zone, which promises advantages for the use of gas mixtures with low reactivity like those occurring in EGR processes. At a pressure of 5 bar it was possible to increase the CO2 concentration in the exhaust gas up to 7 vol%, which is already enough to realize an efficient CO2 capture process. At 10 bar the CO2 concentration could be increased to 9 vol%. The changes in flame stabilization due to pressure increase and different EGR rates are investigated by OH*-chemiluminescence imaging and discussed. The contribution of auto-ignition and flame propagation to flame stabilization is estimated by a kinetic model calculation.

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Prediction of Flame Burning Velocity at Early Flame Development Time With High Exhaust Gas Recirculation (EGR) and Spark Advance

ASME 2016 Internal Combustion Engine Fall Technical Conference ◽

10.1115/icef2016-9476 ◽

2016 ◽

Author(s):

H. Lian ◽

J. B. Martz ◽

B. P. Maldonado ◽

A. G. Stefanopoulou ◽

K. Zaseck ◽

...

Keyword(s):

Laminar Flame ◽

Burning Velocity ◽

Maximum Level ◽

Exhaust Gas Recirculation ◽

Operating Conditions ◽

Exhaust Gas ◽

Flame Velocity ◽

Flame Development ◽

Gas Recirculation ◽

Averaged Model

Diluting Spark-Ignited (SI) stoichiometric combustion engines with excess residual gas improves thermal efficiency, and allows spark to be advanced towards Maximum Brake Torque (MBT) timing. However, flame propagation rates decrease and misfires can occur at high Exhaust Gas Recirculation (EGR) conditions and advanced spark, limiting the maximum level of charge dilution and its benefits. The misfire limits are often determined for a specific engine from extensive experiments covering a large range of speed, torque and actuator settings. To extend the benefits of dilute combustion while at the misfire limit, it is essential to define a parameterizable, physics-based model capable of predicting the misfire limits, with cycle to cycle varied flame burning velocity as operating conditions change based on driver demand. A cycle averaged model is the first step in this process. The current work describes a model of cycle averaged laminar flame burning velocity within the early flame development period of 0 to 3 percent mass fraction burned. A flame curvature correction method is used to account for both the effect of flame stretch and ignition characteristics, in a variable volume engine system. Comparison of the predicted and the measured flame velocity was performed using a spark plug with fiber optical access. The comparison at a small set of spark and EGR settings at fixed load and speed, shows an agreement within 30% of uncertainty, while 20% uncertainty equals ± one standard deviation over 2,000 cycles.

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