An Investigation of the Lean Operational Limits of Gas-Fueled Spark Ignition Engines

1996 ◽  
Vol 118 (2) ◽  
pp. 159-163 ◽  
Author(s):  
O. A. Badr ◽  
N. Elsayed ◽  
G. A. Karim

Examination is made of the operational limits in two variable compression-ratio single-cylinder engines when operating on the gaseous fuels methane, propane, LPG, and hydrogen under a wide range of conditions. Two definitions for the limits were employed. The first was associated with the first detectable misfire on leaning the mixture, while the second was the first detectable firing under motoring condition in the presence of a spark when the mixture was being enriched slowly. Attempts were also made to relate these limits to the corresponding values for quiescent conditions reckoned on the basis of the flammability limits evaluated at the mean temperature and pressure prevailing within the cylinder charge at the time of the spark. The measured limits in the engine were always higher than the corresponding flammability limit values for the three fuels. Both of these limits appear to correlate reasonably well with the calculated mean temperature of the mixture at the time of passing the spark.

1995 ◽  
Vol 117 (3) ◽  
pp. 239-242 ◽  
Author(s):  
S. O. Bade Shrestha ◽  
I. Wierzba ◽  
G. A. Karim

A simple approach is described for the calculation of the rich flammability limits of fuel-diluent mixtures in air for a wide range of initial temperatures based only on the knowledge of the flammability limit of the pure fuel in air at atmospheric temperature and pressure conditions. Various fuel-diluent mixtures that include the fuels methane, ethylene, ethane, propane, butane, carbon monoxide, and hydrogen, and the diluents nitrogen, carbon dioxide, helium, and argon have been considered. Good agreement is shown to exist between predicted values of the rich flammability limits and the corresponding available experimental values for the fuel-diluent mixtures.


Author(s):  
Vinod Kumar Yadav ◽  
Ranjeet Singha ◽  
Abhishek Kumar Pandey ◽  
Saumya   ◽  
Ashish Kumar Singh ◽  
...  

One of the major causes of environmental pollution and ozone layer depletion is the emissions coming out of the combustion devices including industrial burners, automobile vehicles and household appliances. Most of the conventional fuels used now days have high GWP and ODP. So the greatest challenges among the combustion researchers and scientists are to develop some sustainable and non conventional sources of energy that possesses capability to replace the conventional ones. One of the important gaseous fuels in non conventional category is hydrogen, which is a cleaner fuel and reduces pollution enormously. In the present work, experimental & computational analysis of laminar burning velocity (LBV) of premixed gaseous fuels (primary focus on Hydrogen enrichment) was carried out. For experimental investigation the experimental set up available in Fuel and pollution lab of Indian Institute of Technology Delhi is used. Experiments were carried out on mixtures of methane- Air and Methane-Hydrogen-Air for wide range of equivalence ratios and compared with the computational results of PREMIX with full GRI-Mech 3.0 mechanism. Most of the experiments available in literature were carried out at 298 K. In the present work it has been tried to relate the effect of low temperatures on laminar burning velocity of mixtures. The experiments have been conducted at 1 bar pressure and around 292 Kelvin with equivalence ratio ranging from 0.8 to 1.2. Methane gas is enriched with hydrogen in varying proportions and the effect of hydrogen enrichment on its laminar burning velocity studied. The objective of the addition of hydrogen to methane was to increase its laminar burning velocity as well as to extend its lean flammability limits at lower ambient temperatures.


Author(s):  
Guillaume Brecq ◽  
Camal Rahmouni ◽  
Abdellilah Taouri ◽  
Mohand Tazerout ◽  
Olivier Le Corre

Experimental investigations on the knock rating of gaseous fuels were carried out on a single cylinder SI engine of Lister-Petter make. The Service Methane Number (SMN) of different gas compositions is measured and then compared to the standard Methane Number (MN), calculated by the AVL software. Effects of engine parameters, by mean of the Methane Number Requirement (MNR) are also highlighted. A linear correlation, between the SMN and the MN, has been obtained with a maximum absolute deviation lower than 2 MN units. A prediction correlation giving the MNR from engine parameters has finally been deduced from experimental data with a good accuracy (mean absolute deviation of 0.5 MNR unit).


2003 ◽  
Vol 125 (2) ◽  
pp. 500-504 ◽  
Author(s):  
A. A. Attar ◽  
G. A. Karim

The knock tendency in spark ignition engines of binary mixtures of hydrogen, ethane, propane and n-butane is examined in a CFR engine for a range of mixture composition, compression ratio, spark timing, and equivalence ratio. It is shown that changes in the knock characteristics of binary mixtures of hydrogen with methane are sufficiently different from those of the binary mixtures of the other gaseous fuels with methane that renders the use of the methane number of limited utility. However, binary mixtures of n-butane with methane may offer a better alternative. Small changes in the concentration of butane produce almost linearly significant changes in both the values of the knock limited compression ratio for fixed spark timing and the knock limited spark timing for a fixed compression ratio.


1994 ◽  
Vol 116 (3) ◽  
pp. 181-185 ◽  
Author(s):  
I. Wierzba ◽  
S. O. Bade Shrestha ◽  
G. A. Karim

A procedure is described for calculating the lean flammability limits of fuel-diluent mixtures in air over a wide range of fuel-diluent combinations and for different initial mixture temperatures. Good agreement is shown to exist between the predicted values of the limits with the corresponding experimental values for some common gaseous fuels that include CH4, C2H6, C2H4, C3H8, C4H10, H2, and CO and the diluents CO2, N2, He, and Ar over the temperature range of −60°C up to 400°C.


2006 ◽  
Vol 128 (3) ◽  
pp. 223-228 ◽  
Author(s):  
S. O. Bade Shrestha ◽  
Ghazi A. Karim

The operation of engines whether spark ignition or compression ignition on a wide range of alternative gaseous fuels when using lean mixtures can offer in principle distinct advantages. These include better economy, reduced emissions, and improved engine operational life. However, there are distinct operational mixture limits below which acceptable steady engine performance cannot be sustained. These mixture limits are usually described as the “lean operational limits,” or loosely as the ignition limits which are a function of various operational and design parameters for the engine and fuel used. Relatively simple approximate procedures are described for predicting the operational mixture limits for both spark ignition and dual fuel compression ignition engines when using a range of common gaseous fuels such as natural gas/methane, propane, hydrogen, and some of their mixtures. It is shown that good agreement between predicted and corresponding experimental values can be obtained for a range of operating conditions for both types of engines.


Author(s):  
Zdzisław Chłopek ◽  
Jakub Lasocki ◽  
Hubert Sar

AbstractGaseous fuels are increasingly used to power internal combustion engines. Spark-ignition engines are fuelled with liquefied petroleum gas. Engines powered by gaseous fuels are characterized by good ecological properties due to the emission of pollutants. The paper presents the results of empirical tests of two passenger cars with spark-ignition engines powered alternatively: with gasoline and LPG fuel. The engines were equipped with fifth generation LPG fuelling systems. The tests were performed on a chassis dynamometer in tests used in approval procedures in Europe (NEDC test) and in the United States of America (FTP-75 test). These tests were the basis for determining the average specific distance emission of pollutants (carbon monoxide, hydrocarbons, nitrogen oxides and carbon dioxide) during the tests. The engines were also tested in the conditions of the external speed characteristics while accelerating the car in third gear. It was found that the type of fuelling the engines with both fuels has little influence on the dynamic properties of the engine due to the effective power. The tests clearly showed a decrease in specific distance emission of carbon monoxide and carbon dioxide. The relative reduction in specific distance emission of carbon monoxide was in the order of (45–65)%, and carbon dioxide—about 10%. For hydrocarbons, there was an increase in specific distance emission of hydrocarbons for the fuelling of engines with LPG, while for hydrocarbons, there was a large difference in the value of the relative specific distance emission difference for both tests. (The relative difference was from 25 to 175%.) Specific distance emission of nitrogen oxides turned out to be significantly higher when running engines with LPG. The reason for this is leaning of the fuel mixture at high rotational speed during acceleration of the car, which may result from insufficient conversion efficiency of engine control algorithms in the LPG fuel mode.


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