Showing papers on "Spark-ignition engine published in 2005"
01 Jan 2005
TL;DR: In this paper, two stages of stratified combustion (partially premixed flame propagation and mixing-controlled combustion of rich products left from partial combustion of initially fuel-rich mixtures) are investigated in an experimental Spray-Guided Spark-ignited Direct-injection (SG-SIDI) engine using detailed CFD modeling, high-speed spectrally resolved combustion luminosity imaging, and cylinder pressure analysis.
Abstract: Spray-guided spark-ignited direct-injection (SG-SIDI) engines are likely to be the next generation of gasoline engines. Compared to current wall-guided (WG-SIDI) engines, they offer improved fuel economy and substantially reduced hydrocarbon and soot emissions. Two stages of stratified combustion (partially premixed flame propagation and mixing-controlled combustion of rich products left from partial combustion of initially fuel-rich mixtures) are investigated here in an experimental SG-SIDI engine using detailed CFD modeling, high-speed spectrally resolved combustion luminosity imaging, and cylinder pressure analysis. The CFD model reproduces the spatial and temporal distribution of both combustion stages. Correlation of CFD calculations and experimental combustion measurements demonstrates that optimum ignition timing occurs for somewhat rich equivalence ratios (0.9–1.6) and relatively low flow velocities (
131 citations
TL;DR: In this article, a quasi-dimensional spark ignition (SI) engine cycle model is used to predict the cycle, performance and exhaust emissions of an automotive engine for the cases of using gasoline and LPG.
128 citations
TL;DR: In this paper, artificial neural networks (ANNs) were used to determine the effects of intake valve timing on the engine performance and fuel economy, which can be used for the prediction of engine performance as an appropriate method for spark-ignition engines.
126 citations
01 Jan 2005
TL;DR: In this paper, the authors explore the idea of training artificial neural networks (ANN) for ignition delay and coupling ANN with a semi-empirical model to provide a fast and reliable model for SOC.
Abstract: Homogeneously charged compression ignition (HCCI) engine is a desirable compromise between spark ignition engine and compression ignition engine. Despite the many advantageous features of HCCI combustion, controlling the initiation of combustion remains a challenge for practical applications. A fast and accurate model for the start-of-combustion (SOC) can be useful for developing control strategies of HCCI. In this study, we explore the idea of training artificial neural networks (ANN) for ignition delay and coupling ANN with a semi-empirical model to provide a fast and reliable model for SOC. Through extensive comparisons, this model is found to predict SOC in good agreement with those obtained from a well-mixed reactor model using detailed mechanisms. The CPU time for each run takes about 20–30 ms on a PC. The proposed model is potentially promising for use in real-time dynamic control of HCCI engine combustion.
69 citations
Patent•
21 Jan 2005
TL;DR: In this article, a control apparatus is configured to achieve considerably delayed ignition timing and combustion stability, and to bring about an increase in exhaust gas temperature and a reduction in HC discharge when the engine is cold.
Abstract: A control apparatus is configured to achieve considerably delayed ignition timing and combustion stability, and to bring about an increase in exhaust gas temperature and a reduction in HC discharge when the engine is cold. Normal stratified combustion operation and homogeneous combustion operation are carried out when warming has been completed and the coolant temperature of the internal combustion engine has exceeded 80° C. In an injection operation at the top dead center, the injection start timing ITS occurs prior to compression top dead center (TDC) and the injection end timing ITE occurs after compression top dead center (TDC), whereby fuel injection is carried out so as to straddle the compression top dead center. The ignition timing ADV occurs after compression top dead center (TDC) and ignition occurs with a timing that is delayed from the injection start timing ITS.
69 citations
TL;DR: In this article, the role of changes in some key operating variables affecting the production of the pollutants CO, NO x and unburned hydrocarbons are examined and some guidelines for reducing undesirable emissions are outlined.
67 citations
TL;DR: In this article, temperature and air-fuel ratio dependent specific heat ratio functions were derived to minimize the error by using an equilibrium combustion model for burned and unburned mixtures separately.
61 citations
TL;DR: In this paper, an artificial neural network (ANN) is used for predicting the catalytic converter temperature, carbon monoxide (CO) emissions, and catalytic converters' performance in cold start.
59 citations
TL;DR: In this article, the effect of using higher octane gasoline than that of engine requirement on the performance and exhaust emissions was experimentally studied, and it was shown that using octane ratings higher than the requirement of an engine not only decreases engine performance but also increases exhaust emissions.
56 citations
11 Apr 2005
TL;DR: In this article, an analytical formulation of the deadening effect of high frequency pressure oscillations in SI engines has been presented and an analytical solution has been established for future ECU implementation.
Abstract: High frequency pressure oscillations are generated under knocking conditions within the combustion chamber of Spark Ignition engines. Although acousticoscillation model can give the natural frequencies of these oscillations, very few mathematical models are today available, in scientific literature, to describe the oscillation deadening effect. An analytical formulation of the deadening has been highlighted. Analytical solution has been established for future ECU implementation. Coupling this new concept and an existing highfrequency model, an achieved model of the knocking pressure high frequencies is compared to experimental data. Good behavior is obtained on a natural gas fuelled spark ignition engine. BACKGROUND Knock is an undesirable combustion mode occurring in SI engines. It results in an abnormal auto-ignition of the end gas ahead of the propagating flame front. This phenomenon, characterized by the occurrence of pressure oscillations within the combustion chamber resulting in a metallic noise, can lead to irreversible engine damage. Because of increasing environmental concerns and enlargement of fuel diversification, natural gas is more and more considered as a valuable fuel for reciprocating engines and especially SI engines. Because of the absence of anti-knock-additive for natural gas (such as lead tetraethyl for gasoline) and the relative high variability of the natural gas composition (natural gas is a crude hydrocarbon whose composition changes with feedstock location), knocking conditions can easily occur in gas engines. Consequently, although this phenomenon has been extensively studied for more than
49 citations
TL;DR: In this paper, the use of LPG in spark-ignition outboard engines was investigated and the results indicated that specific fuel consumption and CO emissions were much lower without noticeable power loss while HC emissions are shown to be little affected by fuel substitution.
01 Mar 2005
TL;DR: In this article, the effect of ethanol as the co-solvent in the methanol-gasoline blend was investigated, and it was shown that the phase separation problem was solved by adding ethanol to the mixture.
Abstract: One of the major problems for the successful application of a methanol-gasoline blend as a motor fuel was the realization of a stable homogeneous liquid phase. This paper studied the effect of ethanol as the co-solvent in the methanol-gasoline blend in order to overcome this problem. In this way, not only was the phase separation problem solved but the methanol ratio in the blend was also increased. The critical phase separation temperature (CPST) of the methanol-gasoline blend increased with increasing water content in the blend, and the addition of ethanol caused the CPST to decrease. M10 (gasoline containing 8.5 vol % methanol and 1.5 vol % ethanol) and M25 (gasoline containing 19 vol % methanol and 6 vol % ethanol) were exploited to test the performance, the fuel consumption, and the exhaust emissions. The results show that the specific fuel consumption of M10 was almost the same as that of gasoline, but that of M25 was higher for all engine speeds at full load. The specific energy consumption...
TL;DR: In this article, planar sensors based on tape-cast YSZ layers with parallel Pt finger electrodes, one coated with WO3 thick film as sensing electrode, were fabricated.
Abstract: Planar sensors based on tape-cast YSZ layers with parallel Pt finger electrodes, one coated with WO3 thick film as sensing electrode, were fabricated. The sensors were tested in the laboratory at various concentrations of NO2 and CO at different temperatures and oxygen partial pressures. Field tests were also performed; planar sensors were located close to a commercial oxygen sensor, downstream the three-way catalytic converter of a FIAT fire 1242 c.c. spark ignition engine coupled to a dynamometer. The performance of the gas sensors was measured at the air/fuel ratio stoichiometric point (A/F ∼ 14.3) at different engine regimes (RPM and torque) and thus at different operating temperatures. The response of gas sensors was compared with the response of the commercial lambda probe and related to the exhaust gas concentrations measured by spectroscopic analytical equipment at the engine exhaust end. Preliminary measurements showed promising results in terms of sensitivity, stability and reproducibility.
TL;DR: In this paper, the authors evaluated the reliability and combustion sensor properties in controlled environment and on spark ignition engine and found that the sensor was more sensitive towards the first components of mixture, and good response times were observed on engine bench.
Abstract: Increasingly strict emissions regulations and heightened environmental awareness on the part of users around the world have led to energetic research into emissions reduction by various automobile manufacturers and research institutes. In this paper we tested sol–gel TiO2 sensor in order to evaluate the reliability and combustion sensor properties in controlled environment and on spark ignition engine. Experiments were carried out for understanding influence of single gas component of flue gas on the response of TiO2 sensor and evaluate transducer behaviour on real spark ignition engine. Higher responses were obtained for oxygen and nitrogen oxide, rather than CO2 and CH4. So TiO2 sensor was more sensitive towards the first components of mixture, and good response times were observed on engine bench.
Patent•
10 May 2005
TL;DR: In this paper, a spark-ignition engine with a highly structural compression ratio greater than 15: 1, throttle regulation, externally supplied ignition and direct fuel injection into a precombustion chamber (5), which is connected to the main combustion chamber via an overflow channel (6).
Abstract: The invention relates to a spark-ignition engine with a highly structural compression ratio greater than 15: 1, throttle regulation, externally supplied ignition and with direct fuel injection into a precombustion chamber (5), which is connected to the main combustion chamber (15) via an overflow channel (6). The fuel is injected into the precombustion chamber (5) during the compression stroke and is ignited by a spark plug (8) located in a manner that is as central as possible.
TL;DR: In this paper, the authors report results on non-periodic experimental time series of pressure in a single cylinder spark ignition engine and estimate the noise level in internal pressure calculating the coarse-grained entropy from variations of maximal pressures in successive cycles.
Abstract: We report our results on non-periodic experimental time series of pressure in a single cylinder spark ignition engine. The experiments were performed for different levels of loading. We estimate the noise level in internal pressure calculating the coarse-grained entropy from variations of maximal pressures in successive cycles. The results show that the dynamics of the combustion is a non-linear multidimensional process mediated by noise. Our results show that so defined level of noise in internal pressure is not monotonous function of loading.
TL;DR: In this paper, a planar sensor with two parallel Pt finger electrodes, one coated with WO 3 thick film as sensing electrode, was fabricated for field measurements of NO x, HCs and CO concentrations on an engine test bench.
Abstract: Field measurements of NO x , HCs and CO concentrations on an engine test bench were performed on YSZ-based planar sensors. Sensors with two parallel Pt finger electrodes, one coated with WO 3 thick film as sensing electrode, were fabricated. The planar sensor was positioned close to a commercial λ sensor, downstream the three-way catalytic converter of a FIAT fire 1242 cc spark ignition engine coupled to a dynamometer. The performance of the gas sensors was measured at the stoichiometric air/fuel ratio ( A / F ∼ 14.3) and in lean ( A / F ∼ 15) and rich ( A / F ∼ 13) conditions under different engine regimes (rpm and torque). The response of gas sensors was compared to the response of the commercial λ probe and related to the exhaust gas concentrations measured by spectroscopic analytical equipment at the engine exhaust end. Preliminary measurements showed promising results in terms of selectivity, sensitivity, stability, reproducibility, and response time.
Patent•
29 Mar 2005
TL;DR: In this article, the authors proposed a combustion control to suppress torque shock due to momentary increase of torque at a time of transition from a zone performing compression self ignition operation to the zone performing spark ignition in a spark ignition engine.
Abstract: PROBLEM TO BE SOLVED: To suppress torque shock due to momentary increase of torque at a time of transition from a zone performing compression self ignition operation to a zone performing spark ignition in a spark ignition engine. SOLUTION: This engine performs compression self ignition using internal EGR by valve reopening action of an exhaust valve during intake stroke, and is provided with a combustion control means 120 performing compression self ignition by opening an intake valve in neighborhood of intake top dead center and closing the intake valve before bottom dead center and reopening the exhaust valve in a partial load zone and performing spark ignition under a condition where valve reopening action of the exhaust valve is stopped with valve closing timing of the intake valve set at predetermined timing after bottom dead center in an engine heavy load zone. Also a throttle valve control means 123 reducing throttle valve opening at a time of transition from the compression self ignition operation zone to the spark ignition operation zone is provided. Moreover, a torque reduction means 140 reducing combustion torque of the engine for predetermined period right after the transition is provided. COPYRIGHT: (C)2007,JPO&INPIT
TL;DR: In this article, the authors explored two different approaches to achieve HCCI with bioethanol; namely, trapping of internal residual gas and intake temperature heating with a high compression ratio.
Abstract: Bioethanol has been successfully used in conventional spark ignition (SI) internal combustion engines. Homogeneous charge compression ignition (HCCI) combustion, a novel combustion method, has shown the potential for low nitric oxides (NOx) emissions with no particulate matter formation. This paper explores two different approaches to achieve HCCI with bioethanol; namely, trapping of internal residual gas and intake temperature heating with a high compression ratio. For naturally aspirated HCCI operation with residual gas trapping on a spark ignition engine, although the NOx emissions were low, the load range was unacceptably small. When inlet manifold pressurisation was employed, a substantial increase in the upper load boundary could be achieved without any substantial increase in NOx emissions. With forced induction, the feasibility of using boost control as the main method of load control for higher engine loads during HCCI operation has been explored with possible methods of utilizing boost ...
01 Jul 2005
TL;DR: In this paper, a three-valve twin-spark ignition engine was developed to produce a strong tumble flow which was measured by a digital particle image velocimetry (PIV) system.
Abstract: A fuel stratification concept is being researched and developed in a three-valve twin-spark ignition engine. This concept requires that two different fuels or fuel components be introduced into the cylinder separately through two independent inlet ports. The fuels will be stratified laterally by means of strong tumble in the cylinder. Similar to the traditional air/fuel stratification engine, this fuel stratification engine can operate in very lean mixture or high exhaust gas dilution at part loads to reduce fuel consumption and NO;( emissions. While at high-load operation, a higher compression ratio may be allowed owing to a potential increase in antiknock features if the lower research octane number (RON) fuel or component is ignited first, leaving the higher RON fuel in the end gas region. As a result, the fuel economy can be improved not only at part loads but possibly at full loads as well. This paper reports the development of such a fuel stratification engine. Firstly, the intake system of the engine was modified to produce a strong tumble flow which was measured by a digital particle image velocimetry (PIV) system. Then, a two-tracer planar laser induced fluorescence (PLIF) system was developed to visualize the fuel stratification in the cylinder. The engine combustion at part and full loads was also tested and analysed from cylinder pressure history. These research results show that the present strong tumble flow was characterized by a symmetrically distributed mean velocity in the intake stroke and a very small velocity component along the direction of the tumble rotational axis in the compression stroke. This flowfield created good fuel stratification laterally. The lean burn limit was considerably extended at part loads, and the knock limit at high loads also had a noticeable difference when higher and lower RON fuels respectively were ignited first.
01 Apr 2005
TL;DR: In this article, the performance of a catalysed wire-cylinder electrostatic trap has been investigated in a laboratory rig with simulated PM and then in the exhaust of a direct injection spark ignition engine, and the trap achieved capture efficiencies by total particle number exceeding 90 per cent at wire voltages of 7-10 kV, gas temperatures up to 400 °C, and operating durations up to one hour.
Abstract: Health concerns over ultrafine (<100 nm) particles in the urban atmosphere have focused attention on measurement and control of particle number as well as mass. Gasoline-engined as well as diesel-engined vehicles are likely to be within the scope of future particulate matter (PM) emission regulations. As a potential option for after-treatment of PM emissions from gasoline engines, the trapping performance of a catalysed wire-cylinder electrostatic trap has been investigated, first in a laboratory rig with simulated PM and then in the exhaust of a direct injection spark ignition engine. In the simulation experiments, the trap achieved capture efficiencies by total particle number exceeding 90 per cent at wire voltages of 7–10 kV, gas temperatures up to 400 °C, and operating durations up to one hour, with no adverse effects from a catalyst coating on the collecting electrode. In the engine tests, at moderate speeds and loads, capture efficiency was 60–85 per cent in the homogeneous combustion mode and 50–60 per cent, of a much larger number of engine-out particles, in the stratified (overall-lean) mode. Gas residence time in the trap appeared to be a major factor in determining efficiency. The electrical power requirement and the effect on engine back-pressure were both minimal.
11 Apr 2005
TL;DR: In this paper, a support vector machine (SVM) is used to reconstruct the indicated torque from crankshaft velocity in a six-cylinder spark ignition engine, which is then obtained through simple mathematical evaluations, allowing fast reconstruction of indicated torque.
Abstract: This paper proposes the use of support vector machines to reconstruct the indicated torque from crankshaft velocity in a six-cylinder spark ignition engine. Real-time knowledge of indicated torque is typically important for engine diagnostics, and recently, an engine idle speed controller capable of reducing the effects of cyclic combustion variability through the use of indicated torque information was proposed. While measurements of in-cylinder pressure can be used to determine indicated torque, these sensors are generally deemed prohibitively expensive for implementation in a production engine. Estimation methods, particularly traditional model based estimation, are typically computationally expensive and require independent data throughout the cylinder expansion stroke. Overlap of the expansion strokes in a six-cylinder engine complicates the problem and limits the ability of traditional model based approaches in fully reconstructing the torque production process. Intelligent estimation techniques can identify the key characteristics of the instantaneous engine speed as a function of crank angle for the combustion stroke, thereby allowing an optimal subset of the available information to be utilised. A support vector machine approach is used in this paper due to the inherent optimisation of the training procedure, resulting in an optimised prediction matrix. Torque estimation is then obtained through simple mathematical evaluations, allowing fast reconstruction of indicated torque. A comparison between reconstruction performances at different operating points is presented as an evidence of the capabilities of the support vector machines. This paper demonstrates that indicated torque reconstruction with support vector machines in a sixcylinder engine is not only possible, but it can be done with sufficient accuracy for the purpose of advanced engine control applications. INTRODUCTION Combustion in an engine cylinder, even at a fixed operating point, is subject to cycle-by-cycle variations, due to factors such as internal exhaust gas recirculation, uneven air-fuel mixture distribution, and variations in mixture density. During low-load idle conditions, air density and fuel mass fed into the cylinder are at their lowest, thereby increasing the likelihood of uneven distribution of the mixture throughout the cylinder. Consequently, this causes variability in combustion process, and subsequently, indicated torque. As variations in combustion or torque production directly influence engine speed, fluctuations of the crankshaft speed are also increased. These speed fluctuations may lead to unnecessary control action at idle [1], or requirements such as higher idle set points to counteract engine stall, and reduce vehicle noise vibration and harshness quality (NVH). Obviously, increasing idle set points also increases emissions and fuel consumption, and should be avoided. Knowledge of indicated torque generated during the combustion process is desirable for several key applications, such as idle speed control and engine diagnostics. Recently, an engine idle speed controller capable of reducing the effects of cyclic combustion variability was proposed [1]. This relies on information about indicated torque in order to predict and compensate for cyclic variations. While there exist incylinder pressure sensors, and there is a direct correlation between in-cylinder pressure and indicated torque, these sensors are generally deemed too expensive and impractical for implementation in a production line engine. Torque sensors, while available, generally have complicated construction, and their realworld production line performance and reliability are yet to be established. Consequently, there is considerable research into methods that will allow the indicated torque to be inferred from available measurements. Downloaded from SAE International by University of Melbourne, Tuesday, January 07, 2014 06:17:04 PM
11 Apr 2005
TL;DR: An improved scheme employing reference feedforward is proposed and several potential topologies are presented, and nonlinear simulation results are shown in which the system transient responses are improved considerably.
Abstract: The direct-injection spark-ignition engine has emerged as a focus of research in improving fuel economy and controlling emissions. This engine can operate in multiple modes, including a stratified charge mode with an air-fuel ratio as large as 50:1. Operating in stratified mode results in improved fuel economy and reduced CO/sub 2/ emissions. The stratified charge mode is employed during low speed and load conditions, such as during engine idle. The idle speed control problem is cast as a two-input-two-output control problem and a baseline feedback controller is developed based on an existing topology from the literature. Significant delays, however, inhibit our ability to improve the transient response via feedback alone. An improved scheme employing reference feedforward is proposed and several potential topologies are presented. A reference feedforward algorithm is derived and nonlinear simulation results are shown in which the system transient responses are improved considerably.
TL;DR: In this paper, seven common methods based on in-cylinder data, usually applied to determine the combustion parameters (ignition delay and combustion duration), are compared using data provided from a natural gas spark ignition engine operating under lean conditions.
TL;DR: In this paper, video imaging has been used to investigate the evolution of liquid fuel films on combustion chamber walls during a simulated cold start of a port fuel-injected engine with a production, four-valve head and a window in the piston crown.
Abstract: Video imaging has been used to investigate the evolution of liquid fuel films on combustion chamber walls during a simulated cold start of a port fuel-injected engine. The experiments were performed in a single-cylinder research engine with a production, four-valve head and a window in the piston crown. Flood-illuminated laser-induced fluorescence was used to observe the fuel films directly, and color video recording of visible emission from pool fires due to burning fuel films was used as an indirect measure of film location. The imaging techniques were applied to a comparative study of single and dual spray fuel injectors for both open and closed valve injection, for coolant temperatures of 20, 40 and 60°C. In general, for all cases it is shown that fuel films form in the vicinity of the intake valve seats. For closed valve injection, films also form below the intake valves and below the squish region between the intake valves and the cylinder wall, while for open valve injection additional fuel films form below the exhaust valves. It is proposed that fuel films on the head near the exhaust valves are a possible source of unburned hydrocarbon emissions, that pool fires are the main source of soot emissions from properly-maintained gasoline vehicles, and that soot-laden fuel films on the cylinder wall are the main source of soot contamination.
TL;DR: In this paper, the particles at the exhaust of two Port Fuel Injection Spark Ignition (PFI-SI) engines were characterised in terms of number size distribution and chemical properties.
Abstract: The particles at the exhaust of two Port Fuel Injection Spark Ignition (PFI-SI) engines were characterised in terms of number size distribution and chemical properties. Optical techniques based on the Laser Induced Incandescence (LII) and on the Broadband Ultraviolet - Visible Extinction and Scattering Spectroscopy (BUVESS) were applied. The optical results were compared with those obtained by Electrical Low Pressure Impactor (ELPI). The aim of the work was the characterisation of the nanoparticles emitted by Port Fuel Injection Spark Ignition (PFI - SI) engines in terms of number size distribution and chemical-physical properties. Two PFI - SI engines were used for the experiments: a four-cylinder engine and a research optically accessible single cylinder engine. The experiments were performed at the exhaust of a multi-cylinder SI engine equipped with a three way catalyst (TWC) and in the combustion chamber and at the exhaust of a single-cylinder optical engine. High number concentrations of nanoparticles (D < 50 nm) were detected. The presence of carbonaceous particles at the exhausts was due to the ignition of the fuel film deposits on the intake valves and on the cylinder walls. This was demonstrated by the optical measurements performed in the combustion chamber of the research engine. Different engine operating conditions were considered.
24 Oct 2005
TL;DR: In this article, a combination of imaging techniques for investigations of highly transient processes and cyclic variations in internal combustion engines is presented, where a single high-speed camera setup uses a CMOS camera combined with a two-stage image-intensifier and two excimer lasers.
Abstract: A combination of imaging techniques for investigations of highly transient processes and cyclic variations in internal combustion engines is presented. The single high-speed camera setup uses a CMOS camera combined with a two-stage image-intensifier and two excimer lasers. Fuel mixing, ignition and combustion were monitored via planar laser induced fluorescence imaging of toluene as a tracer that was added to iso-octane in combination with the simultaneous recording of light emission from the spark plasma and OH chemiluminescence of the developing flame. Image frame rates of 12 kHz for hundreds of cycles were achieved. Application to misfire events in a spray-guided gasoline direct-injection engine is described to illustrate the merits of the technique.
11 Apr 2005