Fueled Spark Ignition Engine Research Articles

Tribology for Small 2 Stroke Cycle Spark Ignition Engine Fueled by Methanol.

This study is on tribology for smal two stroke cycle spark ignition engines fueled by M85(gasoline 15% + methanol 85%) and M0 (gasoline 100%). Separation occurs when lubrication oil is added to the gasoline-methanol blended fuel. Therefore, lubrication oil is supplied to the intake manifold separately from the fuels, and the oil-to-fuel ratio is about 1 : 30 for M0 and 1 : 60 for M85. Wear data for M85 under constant speed and WOT (wide-open throttle), is compared with data of a M0 counterpart. The sludge formed during engine operation was found to affect the cylinder wear performance.

Performance studies with biomass-derived high-octane fuel additives in a two-stroke spark-ignition engine

The intensive search for alternative fuels for spark-ignition engines has focused attention on fuels which can be derived from biomass. In this regard, orange oil and eucalyptus oil are found to be potential candidates for spark-ignition engines. Their properties are similar to gasoline in nature and they are miscible with gasoline without any phase separation. They can be used in spark-ignition engines with little engine modification as a blend with gasoline fuel. The high octane value of these fuels can enhance the octane value of the fuel when it is blended with low-octane gasoline. Hence, the knock-limited compression ratio (CR) can be further increased when these fuels are blended with gasoline. In the present work, 20% by volume of orange oil and eucalyptus oil were blended separately with gasoline and the performance, combustion and exhaust emission characteristics were evaluated at two different compression ratios. Test results indicate that the performance of fuel blends was much better than the gasoline fuel, in particular at the higher compression ratio. Hydrocarbons and carbon monoxide emission levels in the engine exhaust were considerably reduced with the fuel blends at both the compression ratios tested. Between the two fuel blends tested, eucalyptus oil blend provides better performance than the orange oil blend. The maximum percentage improvement in the brake thermal efficiency obtained with eucalyptus oil blend is about 20.5% at 2 kW, 3000 r.p.m. and CR 9 over the normal gasoline engine.

Bleisensor für flüchtige organische Bleiverbindungen mit direkter elektrischer Anzeige

Lead existing as Pb(C2H5)4 in fuels for sparkignition engines can be detected by thermal decomposition of the Pb(C2H5)4 at 200 °C to 300 °C on sensor devices. The metallic lead is deposited between two platinum electrodes and causes a strong decrease of the electrical resistance between these electrodes. The response time is approximately a few minutes. By this method 15–150 μg Pb/ml can be detected. Little amounts of oxygen (air) disturb the detection of lead, because the oxygene oxidizes the hydrocarbons of the fuel to carboxylic acids, which can contribute noticeably to the electrical conductivity. Therefore, oxygen must be removed before the temperature of decomposition is reached. This can be achieved by slow heating of the fuel, which causes the evaporating fuel to replace the oxygen (air).

A computer simulation of hydrogen fueled spark ignition engine

The work reported here pertains to some of the computer simulation models developed for hydrogen fueled spark ignition (SI) engines. The engine combustion process is modeled by using a semi-empirical turbulent flame speed expression. This combustion model has been employed to account for the hydrogen-air combustion process over a wide range of stoichiometric variables for the Varimax engine operating at various speeds and compression ratios. Based on the computed results, graphs showing the variation of combustion crank angle and flame speed with fuel-air equivalence ratio, engine speed, compression ratio etc., have been plotted.

A study on the combustion of alternative fuels in spark-ignition engines

Theoretical and experimental studies have shown that spark-ignition engine fuel composition can have an influence on performance and exhaust emissions. Studies have been made on gasoline, alcohol, hydrogen and ammonia fuels. Energy content and carbon to hydrogen ratio both are influential in determining engine performance and exhaust content of potential air pollutants exhausted into the atmosphere. Neither hydrogen nor ammonia can produce carbon monoxide or unburned hydrocarbon and theoretically should also give less nitric oxide, at most conditions than do octane and alcohols fuels. Some possible measurements are made using gasoline, methanol and ethanol fuels. These measurements show that there is an increase in engine thermal efficiency and less nitric oxide and carbon monoxide when using methanol and ethanol fuels than that of gasoline. These experiments confirm the theoretical results obtained.

The effects of NO 2 on catalytic oxidation of unburned species from a methanol fueled spark ignition engine

Catalytic oxidation processes of unburned species in methanol combustion products are examined with emphasis on the role of NO 2 . Two kinds of experiments were carried out. One was on the catalytic oxidation of the exhaust gases from a methanol fueled spark ignition engine, and the other on prepared gases which simulated the engine exhaust gases. Exhaust gases of air-fuel equivalence ratio ranging from 0.8 to 1.5 were investigated. In the catalyst bed, unburned methanol, formaldehyde, NO and NO 2 concentrations were determined at gas temperatures ranging from 400 to 540 K. Experimental results were expressed by two parameters, methanol oxidation ratio and NO 2 reduction ratio. As soon as the exhaust gas entered the catalyst bed, methanol was oxidized and its concentration decreased. At the same time, NO 2 decreased, while NO increased. The methanol oxidation ratio had a maximum value at an equivalence ratio of about 1.2 and was related to the NO 2 emission characteristics. The conversion of NO 2 to NO was improved by the presence of methanol and the oxidation of methanol was promoted by NO 2 , within the experimental range. In comparison with ethanol combustion products, the effect of NO 2 in catalytic oxidation was greater for methanol combustion products because of the higher NO 2 concentration in the methanol combustion products.

Performance and emission characteristics of hydrogen fueled spark ignition engine

A study of alternate fuels leads to hydrogen as a candidate fuel for the future. Its remarkable properties provide the potential of high thermal efficiency at part load by operating the engine unthrottled with lean mixtures. The problems of pre-ignition and backfiring could be overcome at a wide range of operation by providing a cold spark plug with a narrow gap and by keeping combustion chamber walls clean. Hydrogen operation of spark-ignited engines has been found to be very profitable at low equivalence ratios both from the point of view of increased thermal efficiency and reduced nitrogen oxides emissions.

Water—ethanol—gasoline blends as spark ignition engine fuels

The miscibility characteristics of hydrated ethanol with gasoline is investigated as a means of reducing the cost of ethanol/gasoline blends for use as a spark ignition engine fuel. For a given percentage of water in the ethanol, the experimental data shows that a limited volume of gasoline can be added to form a stable mixture. Engine experiments indicate that, at normal ambient temperatures, a water/ethanol/gasoline mixture containing up to 6 vol% of water in the ethanol constitutes a desirable motor fuel with power characteristics similar to those of the base gasoline. As a means of reducing the smog causing components of the exhaust gases, such as the oxides of nitrogen and the unburnt hydrocarbons, the water/ethanol/gasoline mixture is superior to the base gasoline.

Behavior of Methanol and Formaldehyde in Burned Gas from Methanol Combustion : A Chemical Kinetic Study

A detailed chemical kinetic model has been proposed to explain the formaldehyde formation in a methanol fueled spark ignition engine. In comparison of the calculated results with the experimental results from a reactor tube, the reactions NO+HO2=NO2+OH and NO2+H=NO+OH became important for methanol oxidation and formaldehyde formation in exhaust gases with a large amount of nitric oxide. Accordingly, N-series reactions should be included in this scheme. According to the calculated results, methanol decreases with an increase of the residence time. On the other hand, formaldehyde increases to maximum value and then slowly decreases. At temperatures in excess of 950 K, methanol and formaldehyde oxidations are rapid, and complete in the residence time of 20 milliseconds. At temperatures below 800 K, methanol oxidation is considerably slower and formaldehyde is accumulated by increasing the residence time. The agreement between experimental and calculated results indicates that this proposed scheme is reasonable for studying formaldehyde formation mechanism.

Performance and NOxEmissions of Spark Ignited Combustion Engines Using Alternative Fuels—Quasi One-Dimensional Modeling I. Hydrogen Fueled Engines

Abstract Hydrogen and methanol have been suggested as potential non-petroleum derived substitutes for current reciprocating engine fuels. The present paper reports the results of a computer simulation of the performance and NOx emissions of hydrogen fueled spark ignition engines. The engine combustion process is modeled by employing a semi-empirical turbulent flame speed expression. The NOx emissions are determined by integrating the chemical rate equations resulting from the extended Zeldovich mechanism over the boundary conditions determined by the cycle analysis. Hydrogen exhibits very rapid burning rates and the resulting high pressures and temperatures lead to fast NO formation and destruction rates. Maximum NO emissions are predicted for lean mixtures near φ = 0.8 in agreement with experimental observations. For richer mixtures rapid decomposition of NO during the expansion stroke lowers exhaust emissions. NOx control by exhaust gas recirculation is much more effective in lean mixtures than in stoic...

Knock Limits and Performance of Some Gaseous Fuels in a Supercharged Spark-Ignition Engine

Observations of knock limits, in terms of ignition time for borderline knock, are presented for methane and propane at a range of supercharge conditions up to 9 ***lbf/in2boost, in a spark-ignition engine of 105 mm bore running at speeds of 600 and 920 rev/min, with compression ratios of 7·7/1 and 9·5/1. Associated measurements of output and economy are given. Less extensive observations on a butane fuel, and on methane-propane and propane-butane mixtures, are also included. From an examination of computed temperature-pressure histories in the unburned portion of the mixture, it is found that the knock limited ignition advance on the propane fuel at chemically-correct mixture can be closely predicted over the full range of operating conditions covered, by the attainment of a certain critical value of a simple parameter.