Showing papers on "Spark-ignition engine published in 2004"

The Contribution of Different Oil Consumption Sources to Total Oil Consumption in a Spark Ignition Engine

Abstract: As a part of the effort to comply with increasingly stringent emission standards, engine manufacturers strive to minimize engine oil consumption. This requires the advancement of the understanding of the characteristics, sources, and driving mechanisms of oil consumption. This paper presents a combined theoretical and experimental approach to separate and quantify different oil consumption sources in a production spark ignition engine at different speed and load conditions. A sulfur tracer method was used to measure the dependence of oil consumption on engine operating speed and load. Liquid oil distribution on the piston was studied using a one-point Laser-Induced-Fluorescence (LIF) technique. In addition, important in-cylinder parameters for oil transport and oil consumption, such as liner temperatures and land pressures, were measured. Engine test data and modeling results were combined to separate and quantify the contributions of oil entrained in the blowby gas flow, oil evaporation, and oil flow past piston and valve guides into the combustion chamber. The results show that the contribution of each consumption source varies with engine operating conditions. At low load, oil flowing into the combustion chamber was found to be the major consumption source (90 percent), while the 1 contributions of oil evaporation and of blowby entrainment became more significant with increasing engine load. The variation of engine speed at full load increased the contribution of all three oil consumption sources. However, the relative importance of each source did not vary significantly with engine speed. The major contributions were from the oil transport (40 to 50 percent) and oil evaporation (30 to 40 percent).

The new AVL CSI engine : HCCI operation on a multi cylinder gasoline engine

Abstract: The practical application of homogeneous autoignition combustion on a 4-cylinder gasoline production engine is mainly determined by system integration and control strategies under real world boundaries. Self ignition conditions are reached by re-breathing of hot exhaust gas into the combustion chamber during the intake stroke. The CSI engine (Compression and Spark Ignition engine) shows maximum flexibility for a precise internal residual gas control with only moderate modification of engine hardware. New algorithms are necessary in order to achieve acceptable NVH behavior (Noise Vibration Harshness), especially for the mode transition between spark ignition (Sl) and homogeneous charge compression ignition (HCCI) operation. The paper describes the steady state and transient behavior of the CSI 4-cylinder engine and the benefits in fuel consumption and exhaust gas emission compared to the base conventional spark ignited gasoline engine and gives a detailed view on the required combustion control strategies, with focus on mode transitions.

Combustion of LPG in a Spark-Ignition Engine

Abstract: Tax concessions promote the use of Liquefied Petroleum Gas (LPG) fuel for automotive use in Europe. Modelling of the LPG evaporation process shows the importance of drawing the liquid from the tank rather than the gas, otherwise the most volatile component (propane) is used more quickly and the composition of the remaining fuel changes. It is shown that the LPG components have similar calorific values to gasoline, however injecting the LPG as a gas into the inlet port causes a loss of volumetric efficiency and peak power.

Improving emissions and performance characteristics of lean burn natural gas engines through partial stratification

Abstract: A partially stratified charge (PSC) engine concept has been developed to improve the combustion process in a spark ignition engine fuelled by natural gas, operating at lean air-fuel ratios. In general, this technique is effective at increasing fuel conversion efficiency and brake mean effective pressure at relative air-fuel ratios greater than lambda = 1.5. Preliminary testing at 2500 r/min showed that PSC reduced combustion duration by almost 10 per cent at a given air-fuel ratio. It was also effective in extending the lean limit of engine operation, which meant that the engine could be run at lower loads without throttling. PSC technology provides an alternative method of load control to throttling, and hence reduces associated pumping losses. Further investigation was conducted at 1500 r/min and a lean air-fuel ratio of lambda = 1.65. PSC was found to significantly improve engine performance when compared with homogeneous charge operation at the same air-fuel ratio. The optimized data were compared to simple throttled and lean baseline data and a dramatic reduction in NOx emissions was observed, with little efficiency penalty. These initial results demonstrate that the leanburn, partially stratified charge strategy is a viable means of engine control, and has significant performance and emissions benefits.

Combustion process in a spark ignition engine: Dynamics and noise level estimation

Abstract: We analyze the experimental time series of internal pressure in a four cylinder spark ignition engine. In our experiment, performed for different spark advance angles, apart from the usual cyclic changes of engine pressure we observed additional oscillations. These oscillations are with longer time scales ranging from one to several hundred engine cycles depending on engine working conditions. Based on the pressure time dependence we have calculated the heat released per combustion cycle. Using the time series of heat release to calculate the correlation coarse-grained entropy we estimated the noise level for internal combustion process. Our results show that for a larger spark advance angle the system is more deterministic.

Nonperiodic oscillations of pressure in a spark ignition combustion engine

Abstract: We report our results on nonperiodic experimental time series of pressure in a spark ignition engine. The experiments were performed for a low rotational velocity of a crankshaft and a relatively large spark advance angle. We show that the combustion process has many chaotic features. Surprisingly, the reconstructed attractor has a characteristic butterfly shape similar to a chaotic attractor of Lorentz type. The suitable recurrence plot shows that the dynamics of the combustion is a nonlinear multidimensional process mediated by stochastic noise.

Characterization of an in-cylinder flow structure in a high-tumble spark ignition engine

Abstract: A strong in-cylinder tumbling flow, which was produced by partially shrouding the lower periphery of the inlet valves, was measured in a three-valve twin-spark spark ignition (SI) engine using digital particle image velocimetry (PIV). Characteristics of the bulk flow, cyclic variation, frequency spectrum of velocity fluctuation, large- and small-scale fluctuation kinetic energy and integral length scale are analysed in detail. The possible effects of these flow characteristics on the charge stratification and subsequent ignition and combustion processes are also discussed. The results have shown that the strong tumble field was characterized by a very small velocity component in the direction of the tumble rotational axis until the late stage of the compression stroke. The cyclic variation of the bulk flow, though still present, was significantly reduced. Towards the end of the compression process, both low- and high-frequency velocity fluctuations were found to be high after the tumble had collapsed. The velocity fluctuation component along the cylinder axis was characterized by higher frequencies. An integral length scale was found in the range of 4-9 mm during the compression stroke. (A)

The relative effects of fuel concentration, residual-gas fraction, gas motion, spark energy and heat losses to the electrodes on flame-kernel development in a lean-burn spark ignition engine

Abstract: The potential of lean combustion for the reduction in exhaust emissions and fuel consumption in spark ignition engines has long been established. However, the operating range of lean-burn spark ignition engines is limited by the level of cyclic variability in the early-flame development stage that typically corresponds to the 0-5 per cent mass fraction burned duration. In the current study, the cyclic variations in early flame development were investigated in an optical stratified-charge spark ignition engine at conditions close to stoichiometry [air-to-fuel ratio (A = 15] and to the lean limit of stable operation (A/F = 22). Flame images were acquired through either a pentroof window (‘tumble plane’ of view) or the piston crown (‘swirl plane’ of view) and these were processed to calculate the intra-cycle flame-kernel radius evolution. In order to quantify the relative effects of local fuel concentration, gas motion, spark-energy release and heat losses to the electrodes on the flame-kernel growth rate, a...

The behaviourt of small- and large-scale variations of in-cylinder flow during intake and compression strokes in a motored four-valve spark ignition engine

Abstract: An experimental study was conducted to investigate the small-scale and large-scale variations of flow within the cylinder of an internal combustion engine (turbulence and cyclic variation) during the intake and compression processes. Spatial fast Fourier transform (FFT) filtering techniques with various cut-off lengths were used to determine whether there existed a particular length scale that differentiated turbulence from cyclic variations. The flow field was measured using a particle image velocimetry (PIV) system, which was set with 1.25 mm grid spacing. From the experiments and analysis, it was found that there was no particular size of vortical structures dominating the flow field during intake and compression strokes over many cycles. It was also found that not only the ensemble-averaged variation but also the standard deviation of the large- and small-scale variations were greater during the early intake and late compression compared with late intake through the early compression process.

Laser Spark Ignition: Laser Development and Engine Testing

Abstract: Evermore demanding market and legislative pressures require stationary lean-burn natural gas engines to operate at higher efficiencies and reduced levels of emissions. Higher in-cylinder pressures and leaner air/fuel ratios are required in order to meet these demands. Contemporary ignition systems, more specifically spark plug performance and durability, suffer as a result of the increase in spark energy required to maintain suitable engine operation under these conditions. This paper presents a discussion of the need for an improved ignition source for advanced stationary natural gas engines and introduces laser spark ignition as a potential solution to that need. Recent laser spark ignition engine testing with natural gas fuel including NOx mapping is discussed. A prototype laser system in constructed and tested and the results are discussed and solutions provided for improving the laser system output pulse energy and pulse characteristics.Copyright © 2004 by ASME

Fuel injection control device for internal combustion engine

Abstract: PROBLEM TO BE SOLVED: To improve combustion performance in stratified charge combustion in an internal combustion engine. SOLUTION: In a cylinder injection type spark ignition engine having a fuel injection valve installed at a roughly center part of a combustion chamber upper surface and having a cavity shape roughly coaxial with a center axis of fuel spray injected from the fuel injection valve on a piston crown surface, a first combustible fuel air mixture is formed before fuel spray impinges on the piston crown surface at spark ignition timing by enlarging fuel spray angle in a relatively low load operation zone during stratified charge combustion operation, and a second combustible fuel air mixture is formed by making fuel spray angle small and making fuel spray once impinge on the piston crown surface in a relatively high load operation zone during stratified charge combustion operation. COPYRIGHT: (C)2004,JPO&NCIPI

Modelling a variable valve timing spark ignition engine using different neural networks

Abstract: In this paper different neural networks (NN) are compared for modelling a variable valve timing spark-ignition (VVT SI) engine. The overall system is divided for each output into five neura...

Internal combustion engine`s e.g. spark ignition engine, exhaust gas treating method for motor vehicle, involves determining temperature model by applying operational parameter for amount of oxygen in exhaust gas block as input signal

Abstract: The method involves determining a temperature model (6) by applying an operational parameter e.g. an expectancy value, for an amount of oxygen in an exhaust gas block (4) as an input signal (2). The expectancy value is compared with a characteristic parameter for a real amount of oxygen in the exhaust gas block for generating a control deviation that is applied for correcting the model. An independent claim is also included for a device for treatment of exhaust gas of an internal combustion engine.

Fuel injection control device for cylinder direct injection type spark ignition engine

Abstract: PROBLEM TO BE SOLVED: To realize stable stratified burning even in the case that an engine temperature is lower than a predetermined value and fuel pressure is lower than a predetermined value. SOLUTION: In this cylinder direct injection type spark ignition engine provided with a piston (8), a fuel injection valve (11) ejecting a fuel directly to a combustion chamber and an ignition plug (12), a cavity (9) having an approximately cylindrical peripheral wall surface (9a) and a bottom wall surface (9b) smoothly connected to the peripheral wall surface (9a) is formed in the crown surface of the piston (8), the ignition plug (12) is arranged in the vicinity of the center of and just above the bottom wall surface (9b), and an injection executing means (25) is provided which ejects fuel like an approximately hollow cone shape from the upper part of the combustion chamber by the fuel injection valve (11) and also executes divided injections that fuel injection from the fuel injection vale (11) is divided into two times of the vicinity of intake top dead center and compression stroke. COPYRIGHT: (C)2005,JPO&NCIPI

Improvement of performance and reduction of pollutant emissions of a four-stroke spark ignition engine fuelled with a mixture of hydrogen and methane as a supplementary fuel to alcohol

Abstract: Owing to the energy crisis and pollution problems of today, investigations have concentrated on decreasing fuel consumption and on lowering the concentration of toxic components in combustion products by using non-petroleum, renewable, sustainable and non-polluting fuels. While conventional energy sources such as natural gas, oil and coal are non-renewable, hydrogen and alcohol can be coupled to renewable and sustainable energy sources. The usage of a mixture of hydrogen and methane as a supplementary fuel to an alcohol-air mixture for spark ignition engines results in a considerable improvement in engine performance and in the reduction of the toxic components in exhaust gases in comparison with the conventional spark ignition gasoline engine. In tests, the gas comprising 40 per cent H2 and 60 per cent CH4 by volume was added to alcohol as 0, 2, 4, 6, 8, 10 and 12 per cent by mass. Operating test results for a range of compression ratio (CR) and equivalent ratio are presented. Gasoline fuel was u...

The new BMW inline six-cylinder spark-ignition engine

Abstract: BMW’s new inline six-cylinder spark-ignition engine sets new standards in specific power, weight and fuel consumption. The fundamentally new design is based on the latest technologies, such as a composite magnesium-aluminium crankcase, electric coolant pump and a further development of BMW’s Valvetronic variable valve timing. With a weight of just 161 kg, this engine offers outstanding performance with a specific power output of 63 kW/dm3 and a 12 % reduction in fuel consumption.

Transient Air/Fuel Ratio Controller Identification Using Repetitive Control

Abstract: Presented in this paper is a feedforward controller identification process for the transient fueling control of spark ignition (SI) engines. The objective of an SI fueling control system is to guarantee a prespecified air-fuel (A/F) ratio, despite changing driver demands commanded through the throttle. The controller identification process is based on standard system identification tools and is comprised of three steps. The first step involves the design and implementation of a repetitive feedback controller. Next, the engine is subjected to a prespecified periodic throttle motion for which the repetitive controller achieves precise A/F control as t→∞. Finally, using the engine speed, the mass air flow, and the fuel pulsewidth information during precise fueling conditions, the feedforward fueling controller is identified using standard parametric system identification tools. This identification process can be performed during engine warm-up, thereby enabling a rapid determination of the fueling requirements as a function of temperature. Experimental validation is provided on a 1999 Ford 4.6L V-8 fuel injected engine with sequential port injection.