Showing papers on "Spark (mathematics) published in 2006"

System and method for improved vehicle response during vehicle acceleration conditions

Abstract: A vehicle control method for a vehicle having an internal combustion engine coupled to a torque converter is described. In one embodiment, the engine air flow and spark are adjusted to control torque converter operation. The method can improve vehicle response to driver accelerator commands.

Spark plug heating for a spark ignited engine

Abstract: A system for an engine of a vehicle, comprising of at least one combustion chamber located in the engine, a delivery system configured to deliver a fuel and a fluid to the combustion chamber, an ignition system including a spark plug configured to ignite the fuel within the combustion chamber, a spark plug heating system configured to supply heat to the spark plug, and a control system configured to vary an amount of heat supplied to the spark plug by the spark plug heating system responsive to a condition of the ignition system

Resistance of Spark Channels

Abstract: A study undertaken to measure the resistance of spark channels in air with two different current waveforms is presented. In one experiment, the spark was created by a Marx generator. In this case, the gap length was maintained at 12.8 cm, and the current flowing through the spark had a peak current lying in the range of 0.2-2.2 kA. The decay time of the current was larger than 100 mus. In the other experiment, the spark was created by a current generator. In that experiment, the gap length was maintained at 1 cm, and the current flowing through the spark had peak-current amplitudes in the range of 35-48 kA. The decay time of the current was larger than 500 mus. The results show that the resistance of spark channels initially decreases, reaches a minimum value, and then recovers as the current in the spark gap decreases. The minimum resistance of the spark channel decreases with an increasing peak current. The results are compared with various theories that attempt to predict the temporal variation of the resistance of spark channels. The comparison shows that further developments in the existing theoretical models are needed in order to reproduce with better accuracy the dynamic behavior of the channel resistance

Ion Current Based Spark Advance Management for Maximum Torque Production and Knock Control

Abstract: The objective of the present work is the development of a closed-loop individual cylinder spark advance control strategy that allows maximizing torque production while keeping the knocking phenomenon at levels considered safe for the engine components The research activity has consisted of several phases: the first one was focused on the analysis of the relationship between knocking level and indicated mean effective pressure The main result of this preliminary phase is a methodology for identifying target values of the chosen in-cylinder pressure based knocking index A subsequent phase of the work has been devoted to a correlation analysis between pressure-based knocking indexes and knocking indexes obtained by processing other combustion-related signals (engine block vibration and ion current), showing that the ion current based system that has been developed allows reaching high correlation levels Finally, in order to achieve the target knocking levels, the spark advance control strategy proposed here consists of two parallel contributions: a slower, adaptive and statistically-based contribution, and a fast but range-limited term The process of designing the controller has been particularly fast and cost-effective, due to the development of a specific software environment that allows verifying the performance the controller would achieve when applied to the actual engine Such structure may be described as a software rapid control prototyping environment, since an experimental database has been used to reproduce in a simulation environment the response of the controlled system (the engine) coupled to the spark advance control system The proposed control strategy has been successfully implemented on a V12 60 liter high performance engine, allowing to maximize output torque while protecting engine components from knock-related damageCopyright © 2006 by ASME

Sparse representations are most likely to be the sparsest possible

Abstract: Given a signal S ∈ RN and a full-rank matrix D ∈ RN×L with N < L, we define the signal's overcomplete representations as all α ∈ RL satisfying S = Dα. Among all the possible solutions, we have special interest in the sparsest one--the one minimizing ||α||o. Previous work has established that a representation is unique if it is sparse enough, requiring ||α||o < Spark(D)/2. The measure Spark(D) stands for the minimal number of columns from D that are linearly dependent. This bound is tight--examples can be constructed to show that with Spark(D)/2 or more nonzero entries, uniqueness is violated. In this paper we study the behavior of overcomplete representations beyond the above bound. While tight from a worst-case standpoint, a probabilistic point of view leads to uniqueness of representations satisfying ||α||o < Spark(D). Furthermore, we show that even beyond this point, uniqueness can still be claimed with high confidence. This new result is important for the study of the average performance of pursuit algorithms--when trying to show an equivalence between the pursuit result and the ideal solution, one must also guarantee that the ideal result is indeed the sparsest.

Multivariable EGR/spark timing control for IC engines via extremum seeking

Abstract: This paper proposes a closed loop multivariable EGR/Spark timing management system for maximum dilution control while maintaining a desired level of combustion stability. A combustion stability measure derived from in-cylinder ionization signals is used as feedback. An extremum seeking algorithm is employed to modulate spark timing in a slow-time scale in order to maximize the steady-state EGR amount. Simulation results based on data collected from a 3.0L V6 engine are also included to illustrate the proposed control strategy.

Experimental Investigation of the Knock and Combustion Characteristics of CH4, H2, CO, and Some of Their Mixtures

Abstract: Experimental data obtained in a single-cylinder, variable compression ratio, spark ignition (SI), cooperative fuel research (CFR) engine when operating on CH4, H2, CO, simulated reforming p...

Method and apparatus for operating a spark-ignited direct fuel injection engine

Abstract: A method and article of manufacture are provided to operate a spray-guided, spark-ignition, direct fuel injection engine, including injecting a first fuel pulse during a combustion cycle, and initiating spark ignition by energizing a spark igniter. A second fuel pulse is injected during the combustion cycle effective to form an ignitable fuel-air mixture proximal to the spark igniter during a period in time whereat the spark igniter is energized. A preferred elapsed time between an end of the first fuel pulse and start of the spark ignition is determined based upon engine load.

Experimental analysis of a double-spark ignition system

Abstract: The spark that ignites the combustible mixtures is a discharge produced between the electrodes of a spark plug, connected to the secondary of a coil at the high voltage. Optimum combustion requires a steady spark, in a volume as large as is possible, and with maximum energy. We propose a solution to increase the plasma volume and present electrical discharge parameters as a function of inter-electrode distances, pressures in the test-reactor and the width of the electrical pulses of the power supply.

Spark advance controller and production machine of spark advance control logic in internal combustion engine

Abstract: A spark advance controller capable of controlling spark advance in an internal combustion engine with high accuracy without requiring a larger number of data maps and performing laborious optimization tests using an actual engine. In the spark advance controller, map data for controlling the spark advance is computed by a numerical simulator simulating an internal combustion engine, and the map data for spark advance control is approximated with a regression model. The spark advance is computed by using the regression model depending on the detected operating conditions.

Piezo-resonance igniter and ignition method for propellant liquid rocket engine

Abstract: An ignition system for a rocket engine utilizes the pressure energy in a propellant flow. The propellant flow generates an oscillating pressure force in a resonance system which is then transmitted to a piezoelectric system. The electrical pulses are utilized to generate a spark in an igniter system spark gap, resulting in ignition. Since the spark energy production is driven by the resonance of the propellant flow, a fully passive auto-ignition system is provided. Once ignition occurs, the resultant backpressure in the combustion chamber “detunes” the resonance phenomena and spark production stops. Furthermore, should the engine flame out, spark production would automatically resume as the propellant valves remain open thereby providing relight capability.

Control system for compression-ignition engine

Abstract: In a control system for a compression-ignition engine whose operation is switchable between a compression-ignition operation in which an air-fuel mixture supplied to a combustion chamber auto-ignites to burn owing to compression and a spark-ignition operation in which the air-fuel mixture is ignited to burn by a spark of a spark plug, it is determined whether a predetermined permissible condition to permit switching from the spark-ignition to the compression-ignition operation is satisfied, and switching from the spark-ignition operation to the compression-ignition operation is permitted when the predetermined permissible condition is satisfied, thereby enabling to expand the compression-ignition operation utilization region so long as permissible in light of the engine operating condition.

Multiple spark pattern internal combustion initiation device and engine using same

Abstract: A multiple spark pattern internal combustion initiation device includes a body defining a prechamber and a plurality of orifices from the prechamber. The device includes at least two electrical circuits which each form a spark gap with an electrical ground inside the prechamber, operable to create a plurality of different spark patterns. The device may be part of an internal combustion engine which includes a housing with a combustion chamber connected to the prechamber, and means for supplying a lean gaseous fuel mixture into the combustion chamber.

Solutions for Improving Spark Plug Life in High Efficiency, High Power Density, Natural Gas Engines

Abstract: Short spark plug life, resulting in increased engine downtime and operating costs, is the primary factor limiting the power density and thermal efficiency in lean burn natural gas engines. Fundamentally, as engine power density increases, spark plug life decreases. Common approaches to increasing spark plug life include use of high melting temperature electrode materials and increased electrode surface area. However, future targets for engine efficiency and power density require more effective system solutions. In order to achieve these system solutions, work has been focused on developing an empirically derived electrode erosion model. This model quantifies spark plug life as a function of spark discharge characteristics, spark plug electrode design, and flow fields in the vicinity of the spark plug gap for different engine power densities. Furthermore, quenching effects resulting from large surface electrodes and smaller spark gaps have been included to verify ignitability for given in-cylinder charge density and air/fuel ratio conditions. A good agreement between experimental data and model predictions has been demonstrated. Finally, a solution for extending spark plug life in high efficiency, high power density, natural gas engines has been proposed. This solution combines high spark power with a spark plug design consisting of small electrode gap, large electrode surface, and with enhanced flow fields at the electrode gap.Copyright © 2006 by ASME

A model of multichannel mode formation in a sliding electric gas discharge

Abstract: An approximate model of multiple spark channel formation in a sliding gas discharge on a dielectric substrate surface is discussed. Each of the parallel sparks is treated as a constant-radius channel being quasi-static in space with a time-dependent resistance approximated by a falling function. The number of active channels as a function of discharge current is obtained empirically from the experiments being analysed. The spark model is then used for computer simulation of multiple spark formation in a conventional pulsed power supply source. The results of simulations for particular setups of earlier published works are shown to be in good agreement with the experimental data of these works.

Optimizing the Transition Process from Sparking for Non-contact TIG Welding Inverters

Abstract: Gas Tungsten Arc Welding (GTAW or TIG) process in many cases, particularly in automated applications, does not have self-starting feature. High-frequency high-voltage AC pulses are required across the weld terminals to initiate sparking that help establishing stable DC current. The purpose of this work is to guide the transition process from creating momentary spark to desired stable welding current with minimum effort from welding inverter as well as from the spark generator. In the process the spark generator becomes repeatable and the system as a whole becomes more reliable. The performance index of this particular work is to eliminate the recurring requirement of high voltage high frequency pulses that emits Electromagnetic Interference.

A Model for Fuel Optimal Control of a Spark-Ignited Variable Compression Engine

Abstract: Variable compression engines are a mean to meet the demand on lower fuel consumptions. A high compression ratio results in high engine efficiency, but also increases the knock tendency. On conventional engines with fixed compression ratio, knock is avoided by retarding the ignition angle. The variable compression engine offers an extra dimension in knock control, since both ignition angle and compression ratio can be adjusted. A vital question is thus what combination of compression ratio and ignition angle should be used to achieve maximum engine efficiency. Fuel optimal control of a variable compression engine is studied and it is shown that a crucial component is the model for the engine torque. A model for the produced work that captures the important effects of ignition and compression ratio is proposed and investigated. The main task for the model is to be a mean for determining the fuel optimal control signals, for each requested engine torque and speed. The contribution is a model suitable for finding this optimal combination. This model consists of well-known components, and the novelty lies in the compilation and validation of the control oriented efficiency model for a variable compression engine. Despite the models simplicity, it describes the indicated work with good accuracy, and suits its purpose of finding optimal control signals. The evaluation shows that a fuel optimal controller based on the proposed model will miss the optimal IMEP with only 1.5%, and that the corresponding loss in engine efficiency is less than 0.5 percentage units.

An Experimental Study of Spark Anemometry for In-Cylinder Velocity Measurements

Abstract: It has been demonstrated by previous researchers that an approximate value of the bulk flow velocity through the spark plug gap of a running spark ignition engine may be deduced from the voltage and current waveforms of the spark. The technique has become known as spark anemometry and offers a robust means of velocity sensing for engine combustion chambers and other high temperature environments. This paper describes an experimental study aimed at improving performance of spark anemometry as an engine research tool. Bench tests were conducted using flow provided by a calibrated nozzle apparatus discharging to atmospheric pressure. Whereas earlier studies had relied upon assumptions about the shape of the stretching spark channel to relate the spark voltage to the flow velocity, the actual spark channel shape was documented using high speed video in the present study. A programmable ignition system was used to generate well-controlled constant current discharges. The spark anemometry apparatus was then tested in a light duty automotive engine. Results from the image analysis of the spark channel shape undertaken in the present study have shown that the spark kernel moves at a velocity of less than that of the free stream gas velocity. A lower velocity threshold exists below which there is no response from the spark. It is possible to obtain a consistent, nearly linear relationship between the first derivative of the sustaining voltage of a constant current spark and the free stream velocity if the velocity falls within certain limits. The engine tests revealed a great deal of cycle-to-cycle variation in the in-cylinder velocity measurements. Instances where the spark restrikes occur during the cycle must also be recognized in order to avoid false velocity indications.© 2006 ASME

Dual-spark pre-chambered spark igniter

Abstract: A dual-electrode spark igniter (100) has two electrodes, center electrode (110) and secondary electrode (120) extending from the plug body (140). During a spark event, electricity flows across a first spark gap from the first electrode to the second electrode. Electricity also flows across a second spark gap from the second electrode to the ground electrode (130).

Automatic spark drill for high pressure experiments

Abstract: A low cost automatic electric discharge spark drill has been developed for the preparation of gaskets for use in high pressure diamond anvil cells. The spark drill is capable of producing centered holes quickly in a wide range of metals. It makes use of a novel electrical feedback system and provides a method for accurate alignment of the cutting tool and gasket.

Arc/spark optical emission spectroscopy correlated with spark location

Abstract: Two or more high-frequency microphones are used to determine where an individual spark or other excitation beam strikes a sample in an optical emission spectroscopy (OES) instrument. The position of the spark can be correlated with the elemental composition of the material in the sample vaporized by the spark. The microphones are placed appropriately in air around a sparker of the instrument, or appropriately on the sample, or on both the sample and in the air. Arrival times of sound from the spark to the microphones, or a difference in the arrival times, yields information, from which the position of the spark relative to the microphones, and hence the absolute position of the spark, is deduced, such as by triangulation. Optionally or in addition, a signal that indicates a time when the spark is produced is correlated with one or more spectra detected by a spectrometer, so a spectrum that results from the vaporized sample can be distinguished from a spectrum that results from heated gas above the sample.

Real-time animation of spark discharge

Abstract: We have developed a CG technique that creates real-time animations of spark discharges. The technique proposed in this paper has factors related to the generation of a discharge, such as electric charge distribution and boundary conditions in a virtual space as the input, and generates spark discharge shape patterns based on the electric field defined by the input information. An electric field is expressed by the Laplace equation. Our method efficiently obtains the numerical solution of the equation using the calculation technique of the conjugate gradient method implemented on GPU, and can cope with dynamic changes in input. It also produces discharge patterns in both two and three dimensions. In addition, an efficient pseudo-dimensional expansion technique is proposed in this paper, which uses multiple two-dimensional electric fields to generate three-dimensional discharge patterns.

Optimization of cold start automotive fuel economy using a spark timing strategy

Abstract: Fuel use during the cold start of an automotive engine can be up to three times higher than when the engine is warm due to increased oil viscosity and subsequently increased friction within the engine. In this work, we investigate whether retarding the spark early during the engine warm up, and subsequently sacrificing early fuel economy for greater initial heat release, can have a beneficial impact on the overall fuel economy. Two methods are used here. Firstly, a reduced order, thermal model for the engine at idle is presented and then used to find the optimal spark timing by applying results from optimization theory. A full order model is then used in a dynamic programming approach to validate the analytical results.