Showing papers on "Spark-ignition engine published in 2002"

Emission of alcohols and carbonyl compounds from a spark ignition engine. Influence of fuel and air/fuel equivalence ratio.

Abstract: A spark ignition engine was used to study the impact of fuel composition and of the air/fuel equivalence (λ) ratio on exhaust emissions of alcohols and aldehydes/ketones. Fuel blends contained eigh...

Experimental Investigation of SI Engine Performance Using Oxygenated Fuel

Abstract: The current experimental study aims to examine the effects of using oxygenates as a replacement of lead additives in gasoline on performance of a typical SI engine. The tested oxygenates are MTBE, methanol, and ethanol. These oxygenates were blended with a base unleaded fuel in three ratios (10, 15, and 20 vol.%). The engine maximum output and thermal efficiency were evaluated at a variety of engine operating conditions using an engine dynamometer set-up. The results of the oxygenated blends were compared to those of the base fuel and of a leaded fuel prepared by adding TEL to the base. When compared to the base and leaded fuels, the oxygenated blends improved the engine brake thermal efficiency. The leaded fuel performed better than the oxygenated blends in terms of the maximum output of the engine except in the case of 20 vol.% methanol and 15 vol.% ethanol blends. Overall, the methanol blends performed better than the other oxygenated blends in terms of engine output and thermal efficiency.Copyright © 2002 by ASME

Hydrogen as a spark ignition engine fuel

Abstract: Review is made of the positive features and the current limitations associated with the use of hydrogen as a spark ignition engine fuel. It is shown that hydrogen has excellent prospects to achieve very satisfactory performance in engine applications that may be superior in many aspects to those with conventional fuels. A number of design and operational changes needed to effect the full potential of hydrogen as an engine fuel is outlined. The question whether hydrogen can be manufactured abundantly and economically will remain the limiting factor to its widespread use as an S.I. engine fuel in the future.

Control system and method for direct-injection spark-ignition engine

Abstract: A control system for a direct-injection spark-ignition internal combustion engine is provided which includes a first control section for switchably controlling a combustion mode between a homogeneous combustion mode and a stratified stoichiometric combustion mode, and a second control section for advancing, at a time of switching from the homogeneous combustion mode to the stratified stoichiometric combustion mode, an ignition timing by an amount for offsetting a variation of torque simultaneously with switching of the combustion mode, gradually retarding the ignition timing after the switching of the combustion mode, and after the ignition timing has retarded a predetermined amount, retarding a compression stroke fuel injection timing in the stratified combustion mode while retarding the ignition timing further. A control method is also provided.

Geometric features of the flame propagation process for an SI engine having dual-ignition system

Abstract: Flame front surface area and enflamed volume (the volume enclosed with flame front) is theoretically analysed for a spark-ignition engine, having cylindrical disc-shaped combustion chamber with two spark plugs located axisymmetrically on cylinder head, between cylinder axis and cylinder wall. Spherical flame front assumption is used. A computer code is developed based on purely geometric consideration of the flame development process in combustion chamber, and is used to investigate the effects of variations of spark plugs' locations on geometric features of the flame front. A comparison has also been made with a spark-ignition engine having one spark plug at the same location. Copyright © 2002 John Wiley & Sons, Ltd.

The Influence of Nitric Oxide on the Occurrence of Autoignition in the End Gas of Spark Ignition Engines

Abstract: Full-cycle simulations of a spark ignition engine running on a primary reference fuel have been performed using a two-zone model. A detailed kinetic mechanism is taken into account in each of the zones, while the propagating flame front is calculated from a Wiebe function. The initial conditions for the unburned gas zone were calculated as a mixture of fresh gas and rest gas. The composition of the burned gas zone at the end of the last engine cycle, including nitric oxide emissions, was taken as rest gas. The simulations confirm that the occurrence of autoignition in the end gas is sensitive on the amount of nitric oxide in the rest gas of the spark ignition engine. The comparison of autoignition timings calculated for a single-cylinder test engine are getting more accurate if the nitric oxide in the initial gases is taken into account. (Less)

Effects of octane number on exhaust emissions of a spark ignition engine

Abstract: This paper deals with the experimental study that aims to examine the effects of octane number of three different fuel oxygenates on exhaust emissions of a typical spark ignition engine. Three commonly used oxygenates, namely methyl tertiary butyl ether (MTBE), methanol, and ethanol, which were blended with a base unleaded fuel in three ratios (10, 15 and 20 vol%), were investigated. The engine emissions of CO, HC, and NOx were measured under a variety of engine operating conditions using an engine dynamometer set-up. It is found that generally as the octane number of the fuel increases the CO and HC emissions decrease but the NOx emission increases for all three blends. Further, for the leaded fuel (RON of 92), as the speed of the engine increases the CO and NOx emissions decrease but the HC emission decreases. A similar trend was found for MTBE blends also. These emission results are presented in terms of octane number and their effects are discussed in this paper. Copyright © 2002 John Wiley & Sons, Ltd.

Modeling of stratified combustion in a direct-ignition, spark-ignition engine accounting for complex chemistry

Abstract: Intake, mixing and combustion processes are simulated in a direct-injection gasoline engine for three substantially different running conditions, including two full loads with homogeneous charge combustion and a part load with stratified charge combustion. The turbulent Flame Speed Closure (FSC) model is implemented into the FIRE code for the three-dimensional simulations of the combustion processes which is the focus in the present paper. To take local mixture properties into account, a complex chemistry mechanism consisting of 100 species and 475 reactions is used to calculate the laminar flame speeds and chemical timescales required by the model. A large range of equivalence ratios, pressures, and temperatures are investigated and the combustion limits are determined. The FSC model is extended to capture the postflame oxidation between excess fuel from the rich mixture and excess air from the lean mixture. The modeling of the flow field, mixture composition, and combustion is compared with optical and pressure measurements in a test-rig engine showing good agreement. The simulation of the stratified charge combustion indicates that the major part of the unburned fuel after the combustion originates from the lean mixture. The calculated amount of unburned fuel is in good agreement with the measured HC emissions.

Control oriented models for TWC-equipped spark ignition engines during the warm-up phase

Abstract: Introduces phenomenological models of the spark ignition engine combustion and the three-way catalyst, able to describe the dynamic behaviors of the system in different operating modes, including the thermal transient, and being sufficiently simple for control synthesis. The models have been validated on experimental data.

Spark ignition internal combustion engine modelling using Matlab

Abstract: A number of Matlab routines for combustion calculations and thermodynamic simulation of spark ignition internal combustion engine operation are described. Functions that return the thermodynamic curve coefficients for a variety of fuel, air, and combustion product species are described. A Matlab version of the Olikara and Borman method for determining the equilibrium state of combustion products is also presented. Additional routines specifically designed for spark ignition engine modelling are also described. Most of the routines included in this report are essentially Matlab versions of the FORTRAN programs presented by Ferguson for spark ignition engine calculations. Comparisons of results from the new Matlab routines and previous routines and data indicate that the new Matlab routines are reliable -- typical deviations from previous results are less than 1%.

Tumbling Flow Analysis in a Four-Valve Spark Ignition Engine Using Particle Image Velocimetry

Abstract: Tumble motion in the cylinder of a four-valve spark ignition (SI) engine with a production-type cylinder head was studied using cross-correlation digital particle image velocimetry (PIV). The in-cylinder flow field was measured on three planes: the vertical symmetric plane of the combustion chamber, the vertical plane through centres of the intake and exhaust valves, and a horizontal plane 12 mm below the cylinder head. Ensemble-averaged mean velocity, velocity fluctuation distribution and cyclic variation of the instantaneous velocity field were analysed. Analysis results show that the tumble vortex is formed in the early stage of the compression stroke and distorted in the late stage of the compression stroke. The tumble centre is nearly in the centre of the cylinder when the tumble forms. Then it moves gradually to the underneath of the exhaust valves as the piston moves up. It is found that the cyclic variation of the tumble motion at a tumble ratio of 0.9 is so great that the ensemble-averaged flow characteristics hardly represent any individual cycle flow behaviours. Distribution of the velocity fluctuation field is inhomogeneous during the whole compression process. As the engine speed changes the large-scale flow structure seems to remain unaffected.

Modelling of a pressure wave supercharger including external exhaust gas recirculation

Abstract: This paper presents a mean value model of a pressure wave supercharger together with a spark ignition engine including external exhaust gas recirculation. The model of the pressure wave supercharger is based on linear one-dimensional gas dynamics. It includes an approach for the mixing zone between exhaust gases and fresh air which permits the calculation of the exhaust gas recirculation rate within the charger. The mass flow of the recirculated exhaust gas is the combined effect of too large an exhaust gas penetration into the cell wheel of the charger and of incomplete scavenging of the cell wheel. The model of the pressure wave supercharger is validated by the identification of four physically based model parameters and shows an error smaller than 5 per cent over the operating range investigated. The model can be integrated into an overall engine system model which predicts transient exhaust gas recirculation effects during load steps with good accuracy. The system model demonstrates that exhaust gas recirculation during transients is mainly caused by incomplete scavenging of the cell wheel and not by the exhaust gas penetration into the cell wheel being too large. Both the model of the pressure wave supercharger and the overall engine system model are validated by steady state and transient measurements on a dynamic test bench.

Spark-ignition engine having direct fuel injection

Abstract: The invention relates to a spark-ignition engine having direct fuel injection, the fuel injector ( 2 ) and the spark plug ( 3 ) being arranged centrally on the upper side of the combustion chamber ( 1 ). The fuel injector produces an asymmetrical injection volume, so that the electrodes of the spark plug ( 3 ) are not directly affected by liquid fuel. The electrodes are, however, situated in a region reached by evaporating fuel.

Detailed Results for Nitric Oxide Emissions as Determined From a Multiple-Zone Cycle Simulation for a Spark-Ignition Engine

Abstract: A thermodynamic cycle simulation was developed for spark-ignition engines which included a formulation using multiple zones for the combustion process and the capability to compute the net nitric oxide (NO) change due to the “thermal” formation mechanism. This simulation was used to complete analyses for a commercial, 5.7 l spark-ignition V-8 engine operating at a part load operating condition at 1400 rpm with an equivalence ratio of 1.0. The engine possessed a compression ratio of 8.1:1, and had a bore and stroke of 101.6 and 88.4 mm, respectively. At the base case conditions, the nitric oxide emissions were 15.7 g/bhp-hr (2903 ppm). The effects of equivalence ratio, combustion duration, spark timing, exhaust gas recirculation, compression ratio, speed and load on nitric oxide changes were examined. Results for instantaneous nitric oxide as a function of crank angle are presented. The use of an adiabatic zone was shown to dramatically increase the nitric oxide levels relative to using the burned gas temperature. For the base case, almost 50% more nitric oxide was computed using the adiabatic temperature relative to the burned gas temperature. The importance of gas temperature, cylinder gas pressure, and composition is illustrated.Copyright © 2002 by ASME

Control apparatus for a direct-injection, spark-ignition engine

Abstract: A control apparatus for a direct-injection, spark-ignition engine including a temperature-condition detector for detecting a temperature condition of the engine catalyst, and a controller for controlling a fuel-injection operation of the engine fuel injector for the engine. The controller controls the fuel injector to perform divided fuel injections of at least a leading fuel injection and a trailing fuel injection during a compression stroke prior to the ignition timing based upon a detection of the temperature condition by the temperature-condition detector in an inactivated state of the catalyst, the trailing fuel injection being performed at such a timing that its mixture concentrates adjacent to the spark plug at the ignition timing by way of high cylinder pressure during a late-stage of the compression stroke, the leading fuel injection being performed at such a timing that its mixture distributes around a mixture layer by the trailing fuel injection at the ignition timing, and a midpoint between an initiation timing of the leading fuel injection and an initiation timing of the trailing fuel injection being positioned within a period during a latter half of a compression stroke.

Analysis of large-scale flow characteristics in a four-valve spark ignition engine:

Abstract: A digital particle image velocimetry (PIV) measurement has been carried out to study the large-scale flow characteristics in a single-cylinder engine with a production-type four-valve cylinder head under one intake port deactivation. The measurement plane was located 12 mm below the cylinder head parallel to the flat piston top. Two-dimensional velocity fields from 100 consecutive cycles were acquired at every 30 crank angle interval in the compression stroke to analyse ensemble-averaged mean velocity, cyclic variation of the swirl motion, low-frequency and total velocity fluctuations and their integral length scales. The analysis shows that as one intake port is deactivated, strong swirl forms at the end of the intake stroke and sustains its flow pattern up to the late stage of the compression stroke with the precessing of the swirl centre. Both swirl ratio and swirl centre show significant cyclic variations in the compression process. A low-frequency component with spatial frequency below 0.05 m...

Spark-ignition engine trends

Abstract: SUBTITLE: IN THE FACE OF GROWING COMPETITION FROM DIESELS AND ALTERNATIVE POWER SOURCES, SOME OF THE LATEST PROTOTYPE AND PRODUCTION GASOLINE-FUELED ENGINES SHOW HOW CONTINUED ENGINEERING DEVELOPMENT IS MEETING DEMANDS FOR MORE POWER, REDUCED FUEL CONSUMPTION AND EMISSIONS, AND MORE EFFICIENT PACKAGING

Control device of direct injection type spark ignition engine

Abstract: PROBLEM TO BE SOLVED: To provide a control device for a direct injection type spark ignition engine in which changing-over between the homogeneous combustion of one run fuel injection and the divided injection stratified lean combustion for activating an exhaust gas purifying catalyst is conducted while the torque step is absorbed. SOLUTION: The control device of the direct injection type spark ignition engine is structured so that the ignition timing is delayed gradually from the homogeneous stoichiometric combustion (air-fuel ratio feedback control) to around the delay side stable limit, and changing-over is made into the stratified stoichiometric combustion in which the mean air-fuel ratio in the combustion chamber is made approximately stoichiometric by putting the fuel in divided injection between the compression stroke and suction stroke and making the part around each ignition plug rich and its outside lean, and at the same time, the total angle delay amount is advanced in a lump to absorb the torque step. Again the ignition timing is delayed gradually to around the delay side stable limit, and then changing-over is made into the divided injection stratified lean combustion in which the mean air-fuel ratio is made lean by decreasing the suction stroke fuel injection amount, and at the same time, and the total angle delay amount is advanced in a lump to absorb the torque step. COPYRIGHT: (C)2004,JPO

Direct injection spark ignition engine

Abstract: By setting the configuration of a cavity (25) of a piston (5) appropriately, tumble is produced in air that is aspirated into a combustion chamber (6) inside a cylinder (3) from an intake port (8), and by means of this tumble, the spray of fuel injected by a fuel injector (12) is caused to gather around the periphery of a spark plug (7). A predetermined tumble in the form of an upright ellipse is set in the longitudinal cross section of the cylinder (3) which includes an injection point (I) of the fuel injector (12) and an ignition point (T) of the spark plug (7). The bottom surface (26) of the cavity (25) is curved so as to conform to the radius of curvature ( R1 ) of the lower end of the elliptical tumble, thereby advancing the formation of elliptical tumble which is unlikely to interfere with the cylinder wall surfaces.