Showing papers on "Spark-ignition engine published in 1984"

Conditionally-Sampled Velocity and Turbulence Measurements in a Spark Ignition Engine

Abstract: Laser Doppler velocimeter measurements have been made in a homogeneously-charged spark ignition engine. With ignition at the side wall of the disc-shaped combustion chamber, the fluid motion in the direction of flame propagation was measured at the center of the chamber. A simultaneous ionization probe measurement was used to identify the time of flame arrival at the velocimeter probe volume. Phase-averaged measurements recorded from many engine cycles were conditionally sampled according to flame arrival time. The results presented show an increase in the unburned gas turbulence from compression, and strongly suggest that cyclic variation in burn duration is caused by cyclic variation in the bulk turbulence intensity ahead of the flame.

The Swirl-Chamber Spark Plug: A Means of Faster, More Uniform Energy Conversion in the Spark-Ignition Engine

Abstract: Bougie d'allumage a chambre tourbillonnaire permettant une conversion d'energie uniforme et plus rapide dans les moteurs a allumage par etincelle

Apparatus for the uniform distribution of fuel to a multi-cylinder spark ignition engine.

Abstract: Apparatus for the distribution of measured quantities of liquid fuel into the induction tracts of a multi-cylinder spark ignition internal combustion engine in which a single fuel metering device (33) is arranged to deliver metered quantities of fuel in accordance with the requirements of the cylinders of the engine into a catchment chamber (21) from which passages (22, 23, 24, 25) extend, each passage connecting to a conduct (31, 32) extending to the induction tract of one cylinder. Gas under pressure is supplied to the catchment chamber in such an amount and in such a direction that discrete quantities of fuel are delivered in turn along the passages (22, 23, 24, 25) to the cylinders. Preferably, the introduction of gas under pressure is controlled by means of solenoid valves (38, 39), one for each cylinder the operation of which is controlled by a timing device.

The Performance of a Spark-Ignition Engine Fuelled with Natural Gas and Gasoline

Abstract: An experimental evaluation has been made of the power output, specific fuel consumption and thermal efficiency of a modern 4 cylinder spark ignition engine operating on gasoline and natural gas Tests have been conducted at various speeds, spark advance angles and airfuel ratios, all at wide open throttle Performance on gasoline and natural gas has been compared and optimum spark advance determined for natural gas operation With natural gas operation, brake power was found to decrease by between 113% and 166% compared to gasoline operation Brake specific fuel consumption was found to decrease with natural gas operation, although this is due to the higher calorific value of natural gas In terms of brake thermal efficiency, operation with natural gas was found to be less efficient than with gasoline This is due to the lower flame speed of natural gas and the proportionally higher friction losses at the reduced power levels

The Effect of Atmospheric Conditions on the Performance of an Air-Borne Two-Stroke Spark-Ignition Engine

Abstract: The effect of changes in atmospheric pressure and temperature on the performance of a crankcase-scavenged spark-ignition two-stroke cycle engine has been investigated. A detailed computer code has been developed to simulate the two-stroke cycle and was used to evaluate an optimal engine design for best performances at high altitude conditions. The model which includes detailed computations of the scavenging process, calculations of the flows into and out of the engine, empirical expressions for the combustion process, and a practical approach for the heat transfer has been calibrated by using experimental results. An empirical correlation has been devised for the prediction of the indicated power and for the specific fuel consumption of an engine at any pressure and temperature using information obtained at normal atmospheric conditions. These are The correlations have been compared with some other suggested correlations and were found to best fit experimental observations for three different makes of engine.

Water-Ethanol-Gasoline Blends—Physical Properties, Power, and Pollution Characteristics

Abstract: Factors relevant to the utilization of nonanhydrous ethanol as a blending component with gasoline for use in current on-the-road spark ignition engines are investigated. Miscibility limits are determined and key physical properties important for proper engine operation are measured. Dynamometer tests on an unmodified production engine with hydrated ethanol-gasoline blends containing varying percentages of water show potential for increased thermal efficiency and reduced oxides of nitrogen emissions.

Analysis of combustion patterns effective in improving anti-knock performance of a spark ignition engine

Abstract: Measures to improve specific fuel consumption of a spark-ignition engine have been taken by improving indicated thermal efficiency and reducing engine friction loss. In this work higher compression ratios have been used as a means of improving thermal efficiency and so improve specific fuel consumption. Higher compression ratios result in the phenomenon of knocking under full load and is studied in the article. The studies described evaluated the mechanism of knocking, and its relationship with combustion pattern, using a knocking-prediction mathematical model. The purpose of the study involved a need to control the knocking caused by a higher compression ratio, by means of modifying the pressure rise during combustion. (TRRL)

Similarity of some organic compounds in spark-ignition and diesel engine particulate extracts.

Abstract: The abundance and distribution of selected polycyclic aromatic hydrocarbons (pah) and oxy-pah, as well as the alkyl homologues of each, produced by automobiles equipped with diesel and spark-ignition engines were compared. These different engine types produced pah and oxy-pah mixtures which were qualitatively and quantitatively similar; thus, it will be difficult to differentiate diesel emissions from those produced by spark-ignition engines once they enter the environment. (Author/TRRL)

Evaluation of dissociated and steam-reformed methanol as automotive engine fuels

Abstract: Dissociated and steam reformed methanol were evaluated as automotive engine fuels. Advantages and disadvantages in using methanol in the reformed rather than liquid state were discussed. Engine dynamometer tests were conducted with a four cylinder, 2.3 liter, spark ignition automotive engine to determine performance and emission characteristics operating on simulated dissociated and steam reformed methanol (2H2 + CO and 3H2 + CO2 respectively), and liquid methanol. Results are presented for engine performance and emissions as functions of equivalence ratio, at various throttle settings and engine speeds. Operation on dissociated and steam reformed methanol was characterized by flashback (violent propagation of a flame into the intake manifold) which limited operation to lower power output than was obtainable using liquid methanol. It was concluded that: an automobile could not be operated solely on dissociated or steam reformed methanol over the entire required power range - a supplementary fuel system or power source would be necessary to attain higher powers; the use of reformed mechanol, compared to liquid methanol, may result in a small improvement in thermal efficiency in the low power range; dissociated methanol is a better fuel than steam reformed methanol for use in a spark ignition engine; and use of dissociated or steam reformed methanol may result in lower exhaust emissions compared to liquid methanol.

Method for mixture preparation in a spark ignition engine and spark ignition engine for performing the method

Abstract: In the mixture preparation method the fuel, fed to a mixing chamber by means of an injection nozzle, is mixed with aspirated air from the engine In the spray area of the injection nozzle the fuel is vaporised by heating, thereby achieving a reduction of the CO content of the engine exhaust gas In a spark ignition engine with carburettor, a heating element (10) is arranged in the mixing chamber (4) in the area of the outlet orifice of the mixing pipe (2) As in the engine with carburettor, a reduction of the CO content of the exhaust gas is also achieved in an engine with injection pump by arrangement of the heating element in direct proximity, that is in the spray area of the injection nozzle (Fig 1)

Turbocharged Spark Ignition Engine Simulation

Abstract: A detailed simulation of a turbocharged spark-ignition engine is presented. The model is based on the "control volume" concept, yet includes pressure wave action effects in manifold pipes. Each cylinder is considered as a thermodynamic control volume. Manifolds are considered as pipes bounded by volumes (which may be small enough to represent pipe junctions). The program is of modular form, hence any number of cylinders may be specified, along with pipes, turbocharger, waste-gate, EGR system and throttle in almost any arrangement. Energy mass flow and gas dynamic equations are solved in a quasi-steady manner at 1 deg crank angle steps. The accuracy of the simulation is illustrated over a wide range of speed and load, by comparison with detailed test results, from an Audi 200T engine. The utility of the model is shown by predicting the effect of design changes aimed at improving low engine speed boost pressure and turbocharger response, plus boost control at higher speeds.

Rotary internal combustion engine

Abstract: The rotary internal combustion engine may be designed as a diesel or a spark ignition engine It has a rotor 1 rotating about its centroidal axis in a fixed housing 3, in which rotor slide valves are supported so that they are radially displaceable At least two sets each of one working chamber 5 and one intake chamber 4 are arranged rotationally symmetrical in the housing An exhaust port 8 leads into each working chamber and an intake port 7 into each intake chamber Three slide valves 2 for each set of chambers are supported in the rotor The number of spark plugs 9 (spark ignition engine) or of injection nozzles corresponds to the number of chamber sets The design is simple and symmetrical, permitting very quiet running at a low load

Transient heat flux measurement in the combustion chamber of a spark ignition engine by A. C. Alkidas and J. P. Myers. Discussion

Abstract: Etude critique d'une communication consacree a une methode de mesure du flux thermique transitoire dans le cylindre d'un moteur a essence et reponse de l'auteur

Device for reducing the fuel consumption in motor vehicles with spark-ignition engine

Abstract: At higher engine speeds of a motor vehicle spark-ignition engine the intake volume of combustion air increases. This increased air requirement produces a greater drop in pressure on the air filter, which has detrimental effects on the supply of combustion air to the engine. In order to compensate for this fall in pressure at higher speeds of travel, it is proposed to provide a component (4) with an air inlet opening widening in the shape of a funnel for the combustion air, which is connected by way of a hose connection (10) to the air intake pipe (2) of the air filter housing (1) and aligned with its inlet opening towards the oncoming air (12). A considerable reduction in the fuel consumption was noted.

Combustion Process of Torch-Ignited Nonhomogeneous Mixtures : An Experiment with a Constant Volume Bomb

Abstract: Rapid combustion of lean mixtures in a spark ignition engine is a concept promising for the fuel economy as well as the emission control. Torch ignition and/or the use of nonhomogeneous mixtures such as a stratified charge may be the means of their rapid burning. The flame propagation characteristics of nonhomogeneous mixtures were experimentally estimated by a constant volume combustor equipped with a single-shot fuel injection system and a prechamber. This combustor enabled preparation of various nonhomogeneous states of the mixture to be burned by a torch. It was found in such a nonhomogeneous state a formed by the direct injection of fuel that even fairly lean mixtures could be burned as rapidly as the stoichiometric mixture.

Report on Investigation of Alcohol Combustion Associated Wear in Spark Ignition Engines, Mechanisms and Lubricant Effects.

Abstract: : An investigation of the effects of alcohol fuels on spark ignition engine wear and deposition was jointly sponsored by the U.S. Department of Energy and the U.S. Army Belvoir Research and Development Center. This research has investigated four alcohol-containing fuels: pure methanol, pure ethanol, methanol in unleaded gasoline, and ethanol in unleaded gasoline (gasohol). Tests were conducted using a variety of single-cylinder research engines and production multicylinder engines, mounted in dynamometer test stands. This testing indicated that pure alcohol fuels reduced the buildup of engine deposits. Also, neat methanol greatly increased engine wear rates at engine temperatures below 75 C, while anhydrous ethanol and the alcohol-gasoline blends did not increase wear rates over that of unleaded gasoline. Engine-based tests were conducted to investigate the effects of variations in lubricant base stocks and additive formulations on the wear observed with methanol. To determine interaction between fuel alcohols and engine metals, two approaches were developed. The role of nitrogen in the wear process was studied by operating a 2.3-litre engine fueled with methanol in a nitrogen-free atmosphere. Bench experiments indicated that formic-acid and peroxides are formed as methanol combustion intermediates. Originator-supplied keywords include: Combustion, Lubrication, Additives, Corrosion, Formic-acid.

Aldehyde Emissions Of A Methanol Fueled Spark Ignition Engine

Abstract: Methanol, as one of the attractive alternative liquid fuels for spark ignition engines possesses a strong potential of lower exhaust emissions of nitric oxide, carbon monoxide and unburnt hydrocarbons in comparison to gasoline. However, increased aldehyde emissions is a specific disadvantage for methanol's use in spark ignition engines. Experimental investigations relating to the influence of several engine operating parameters and also the effect of mixture preparation methods are reported in this paper. A statistically derived correlation between aldehyde emissions and exhaust gas temperature is described.

Structure of combustion chamber of kerosene spark- ignition engine

Abstract: PURPOSE:To prevent deterioration of thermal efficiency and knocking from occurring by facilitating starting, by so constituting that a plurality of spark plugs are provided by fronting on a combustion chamber of kerosene, and one of the spark plugs is arranged within a recessed combustion chamber so that an air-fuel mixture sojourns within the recessed combustion chamber and is heated. CONSTITUTION:Two spark plugs 5, 6 are arranged by fronting on a combustion chamber 4 of kerosene. A spark gap of the one side spark plug 6 is on the bottom of a cylindrical recessed combustion chamber 7 opened in the combustion chamber 4. A ceramic heat accumulating material 8 is being secured to form the recessed combustion chamber 7, an electric resistor 10 is built in a thick part of the heat accumulating material 8 so that an inner surface 9 is surrounded by the resistor 10 and the resistor 10 is connected in series with an electric power source through lead wires 11, 12. When a switch 13 is turned ON during operation, the resistor 10 is heated and the inner surface 9 of the heat accumulating material 8 is heated. An air-fuel mixture, therefore in the inside of the recessed heat accumulating chamber 7 is heated and turned into an ignitable atmosphere. The resistor 10 is electrified at the time of starting under a low temperature and idling, and evaporation of kerosene in the inside of the recessed combustion chamber 7 is made to accelerate.

Mathematical modelling of spark ignition engine combustion

Abstract: Spark ignition engine combustion can be modelled with a varying degree of detail depending on how the governing equations are formulated and how the turbulent flow is considered to affect the flame propagation process. A classification of model types is constructed on this basis and the mathematical procedures involved in their development are outlined. The simpler, ‘zero-dimensional’ models invariably incorporate “phenomenological” sub-models to describe particular aspects of the combustion process and are especially suitable for parametric studies. They evaluate engine performance satisfactorily and have been instrumental in determining the mechanisms of formation/destruction of certain exhaust pollutants. The most detailed, multi-dimensional (MDM) models have the potential to resolve the turbulent, temperature and species fluctuations both spatially and temporally. Currently, they are restricted in this by computer storage and cost constraints and by inadequate sub-grid scale models for turbulence and chemical reactions. “Hybrid” models retain a little of the detail and spatial resolution of MDM models but without the associated computational cost difficulties. These couple the momentum conservation equation with certain of the “phenomenological” sub-models in the “zero-dimensional” classification and could evolve as the most suitable and cost effective for spark ignition engines.