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Showing papers on "Spark-ignition engine published in 1994"


Journal ArticleDOI
TL;DR: In this paper, the use of hydrogen and hydrogen-enriched gasoline as a fuel for SI engines and the techniques used to generate hydrogen from liquid fuels such as gasoline and methanol, onboard the vehicle are evaluated.

226 citations


Journal ArticleDOI
TL;DR: In this article, a two-dimensional LIF technique was applied to a spark-ignition engine and the fuel distribution at the ignition time was recorded, and the resulting images were processed and converted into fuel/air equivalence ratio using an in situ calibration technique.

96 citations


Proceedings ArticleDOI
29 Jun 1994
TL;DR: In this article, the authors investigate the effect of the main system noise (or disturbance) on accurate air/fuel ratio control of a four cycle spark ignition (SI) engine.
Abstract: Physically a four cycle spark ignition engine operates on the basis of four engine processes or events: intake, compression, ignition (or expansion) and exhaust. These events each occupy approximately 180/spl deg/ of crank angle. In conventional engine controllers, it is an accepted practice to sample the engine variables synchronously with these events (or submultiples of them). Such engine controllers are often called event-based systems. Unfortunately the main system noise (or disturbance) is also synchronous with the engine events: the engine pumping fluctuations. Since many electronic engine controllers are event sampled systems, the sampling frequency is thus also frequency locked to the main system disturbances. This creates a signal analysis problem which has, to the authors' knowledge, not been treated in detail in the literature. This paper concerns itself with the impact of this and related problems on accurate air/fuel ratio control of a spark ignition (SI) engine.

71 citations



Journal ArticleDOI
01 Jan 1994
TL;DR: In this paper, a planar laser-induced fluorescence (PLIF) method for imaging the in-cylinder fuel concentration in a spark-ignition engine is presented, based on fluorescence from a carbonyl compound added to the fuel and excited by an excimer laser at 308 nm.
Abstract: We present a quantitative planar laser-induced fluorescence (PLIF) method for imaging the in-cylinderfuel concentration in a spark-ignition engine. The method is based on fluorescence from a carbonyl compound added to the fuel and excited by an excimer laser at 308 nm. The method has been applied to the study of charge stratification in a lean burn engine equipped with a four-valve pent-roof clinder head. In this engine, stratification is achieved by fuel injection through an inlet valve, the paths of rich fuel pockets from induction through compression to the point of ignition is shown by a series of crank-angle-resolved air-to-fuel ratio (AFR) images.

46 citations



Journal ArticleDOI
TL;DR: In this article, the reactivities of engine-out exhaust hydrocarbon (HC) emissions in photochemical smog formation have been determined for three fuels (isooctane, an aromatic blend, and a gasoline) in a single-cylinder, spark-ignited engine.
Abstract: The reactivities of engine-out exhaust hydrocarbon (HC) emissions in photochemical smog formation have been determined for three fuels (isooctane, an aromatic blend, and a gasoline) in a single-cylinder, spark-ignited engine. High resolution capillary GC was used to determine the mole fractions of the exhaust hydrocarbon species. Temperature programmed chromatography on a single capillary column was sufficient to separate the major exhaust species. A library of approximately 160 hydrocarbon species was used to identify typically 90–95 % of the HC species present. GC-MS was used selectively to verify peak assignments. The effect of engine operating parameters (fuel-to-air ratio, spark timing, and speed) on reactivity was examined. Engine operating parameters affect both total emissions [g/mile] and the specific atmospheric reactivity [g ozone/g HC emissions] of these emissions. Changing the operating parameters to control total emissions may not be as effective as expected in controlling the total reactivity [g ozone/mile] of the emissions because the specific reactivity can also change simultaneously. Effects of changes in operating parameters differ significantly as the type of fuel is varied. The ability to measure exhaust hydrocarbon species emissions accurately and quickly will increase in importance as reactivity-based emissions standards come into widespread use.

33 citations


Journal ArticleDOI
TL;DR: In this article, a 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.
Abstract: 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.

31 citations





Journal ArticleDOI
TL;DR: In this article, the results of testing a Ricardo E6 research engine on hydrogen employing a specially developed solenoid actuated injector were presented, which utilized an elastomeric seat to ensure that the injector did not leak when closed.



Journal ArticleDOI
TL;DR: In this paper, a model of a spark-ignition engine and the dynamic of the vehicle is presented to describe the behavior of the outputs useful for control, such as mechanical performance, fuel-air ratio and cylinder pressure.

Patent
09 Nov 1994
TL;DR: In this article, the authors proposed a method for adaptive control of the timing of a spark-ignition engine on the basis of the equation Y=aX+b, where Y is the ignition timing expressed by the crank angle before top dead center.
Abstract: A spark-ignition engine that has a cylinder and a crank connected to the piston in the cylinder and which converts the reciprocating motion of the piston to rotary motion via the crank, characterized in that said engine further includes: an angle sensor for measuring the crank angle; a combustion sensor for measuring the burned mass fraction of a fuel in the combustion chamber; a computing unit for calculating the ignition timing of the spark-ignition engine on the basis of the measured crank angle and burned mass fraction by the following equation: Y=aX+b (where Y is the ignition timing expressed by the crank angle before top dead center; X is the difference between the crank angle at a reference burned mass fraction of the fuel injected into the cylinder and the crank angle at a burned mass fraction in the progress of combustion; a and b are constants determined by the characteristics of the spark-ignition engine); and a control unit for controlling the ignition timing of the spark ignition engine on the basis of the calculated ignition timing. Also, disclosed is a method for adaptive control of the ignition timing on the basis of the equation Y=aX+b.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the performance of a retrofitted, large combustion chamber with a nonideal spark plug location and showed that the torch-ignited engine is capable of operating at maximum brake torque spark timings.
Abstract: Sluggish flame initiation and propagation, and even potential misfiring, become major problems with lean-fueled, premixed-charge, spark-ignited engines This work studies torch ignition as a means for improving combustion, fuel economy, and emissions of a retrofitted, large combustion chamber with nonideal spark plug location A number of alternative configurations, employing different torch chamber designs, spark-plug locations, and materials, were tested under full-load and part-load conditions Results indicate a considerable extension of the lean operating limit of the engine, especially under part-load conditions In addition, torch ignition can lead to substantial thermal efficiency gains for either leaner or rich air-fuel ratios than the optimum for the conventional ignition system On the richer side, in particular, the torch-ignited engine is capable of operating at maximum brake torque spark timings, rather than compromised, knock-limited spark timings used with conventional ignition This translates into thermal efficiency improvements as high as 8% at an air-fuel ratio of 20:1 and full load


Patent
31 Jan 1994
TL;DR: In this paper, a control system for controlling the flow of inlet air into a supercharged spark ignition engine is described, which comprises air expansion and compression means (19), an inlet port control means (20), an air flow throttle valve (21) located upstream of said expansion, and a bypass duct (21), which can optionally bypass air around the expansion, compression, and expansion.
Abstract: A control system for controlling the flow of inlet air into a supercharged spark ignition engine (40) is described The system comprises air expansion and compression means (19), an inlet port control means (20) for controlling the intake of air into the expansion and compression means (19), an air flow throttle valve (21) located upstream of said expansion and compression means (19) and a bypass duct (21) which can optionally bypass air around the expansion and compression means (19) The air supply to said engine may be throttled by said throttle valve before passing to the engine (40) via said expansion and compression means (19) or said bypass duct (27) An element of control over the power losses associated with the expansion and compression means is thereby provided

Proceedings ArticleDOI
01 Oct 1994

Journal ArticleDOI
TL;DR: In this paper, the ion current signal from a spark plug used as an ion probe, pressure history and flame development were measured in a homogeneous propane-air mixture in closed combustion chambers.
Abstract: In order to investigate the relation between ion current and combustion characteristics, ion current signal from a spark plug used as an ion probe, pressure history and flame development were measured in a homogeneous propane-air mixture in closed combustion chambers. When negative bias is applied to the central electrode of the spark plug, the ion current flows only due to an early flame kernel existing near the spark plug. When positive bias is applied to the central electrode, the ion current flows from the central electrode to the combustion chamber wall and to the ground electrode. Consequently, the ion current is dominated by the contact area between the flame and combustion chamber wall. The appearance time of ion-current peaks is related with combustion duration.

Proceedings ArticleDOI
Dorey1, Stuart
24 Aug 1994
TL;DR: In this article, the application of self-tuning concepts to the problem of extremum control for the in-vehicle calibration of a spark ignition engine was described and various implementations of least squares estimation were considered and used in the work.
Abstract: The paper describes the application of self-tuning concepts to the problem of extremum control for the in-vehicle calibration of a spark ignition engine. Various implementations of least squares estimation are considered and used in the work. It is shown that improved performance is obtained by combining an angle of peak pressure regulator with the self-tuning extremum controller. >

Proceedings ArticleDOI
TL;DR: In this paper, two-components cycle-resolved laser Doppler Velocimetry (LDV) measurements were performed with high data rate to resolve the flow in a spark ignition engine.
Abstract: Two-components cycle-resolved Laser Doppler Velocimetry (LDV) measurements were performed with high data rate to resolve the flow in a spark ignition engine. The velocity measurements were then processed with both a frequency and a time domain filtering technique to obtain the level of turbulence at different frequencies. Simultaneous cylinder pressure measurements gave information of the duration of the early flame development through a heat release calculation. The initial combustion rate was correlated to the turbulence at different frequencies and the results showed a higher correlation for the high frequencies (4-6 kHz) when the engine was run at 700 rpm. (Less)

Patent
30 Jun 1994
TL;DR: In this paper, a reducing agent is supplied to the combustion chambers of a compression ignition or lean burn spark ignition engine to reduce the discharge of NOx in the exhaust gases, which may be ammonia, hydrazine or cyanuric acid and may be contained in a Cetain improving solvent.
Abstract: A reducing agent is supplied to the combustion chambers of a compression ignition or lean burn spark ignition engine to reduce the discharge of NOx in the exhaust gases. The agent which may be ammonia, hydrazine or cyanuric acid and may be contained in a Cetain improving solvent, is metered into the fuel in the fuel tank, to the air intake or to be recirculated exhaust gases or injected to the combustion chamber through a glow plug. The cyanuric acid may be in a sublimable powder form which is supplied in an amount dependent on the peak combustion temperature and transported by air from a fan. An organometallic additive may be metered to the fuel tank to provide cleaning of a regenerative particle trap in the engine exhaust.

Proceedings ArticleDOI
29 Jun 1994
TL;DR: The identification study for the fuel flow dynamics, conducted via a least square technique, provides the basic information in describing the fuel behaviour for a port injection engine.
Abstract: In the framework of a mean value dynamic model for the prediction of fuel consumption and emissions during driving cycles, the air flow and the two phase fuel flow sub-models are presented. To validate these sub-models, an experimental investigation on an electronically controlled multi-point injection engine has been carried out. A satisfactory agreement between predicted and measured data is obtained consistently with the objectives of the whole engine dynamic model. Furthermore, the identification study for the fuel flow dynamics, conducted via a least square technique, provides the basic information in describing the fuel behaviour for a port injection engine. Particularly no dependence from engine parameters has been noticed except for the amount of fuel flowing through the intake valve as liquid phase.

Journal ArticleDOI
TL;DR: In this article, laser Rayleigh scattering was applied for remote, nonintrusive point probing of the vapor concentration and its fluctuation near the spark plug of a motored spark ignition engine, which was caused by the intermittent injection of Freon-12 vapor into an intake port.
Abstract: Laser Rayleigh scattering was applied for remote, nonintrusive point probing of the vapor concentration and its fluctuation near the spark plug of a motored spark ignition engine, which was caused by the intermittent injection of Freon-12 vapor into an intake port. The theoretical analysis showed that the instantaneous fuel vapor concentration can be split into three components : the ensemble-averaged mean concentration, the cyclic variation of temporal mean concentration and the temporal concentration fluctuation in a specific cycle. This paper concentrates on the measurements of the ensemble-averaged mean concentration and the cyclic variation of temporal mean concentration. The results show that both the ensemble-averaged mean concentration and the cyclic variation of temporal mean concentration increase and reach a peak, after which they decrease during the intake and compression strokes. Moreover, they are strongly affected by air-fuel ratio, engine speed, injection duration and injection timing.