Numerička analiaza izgaranja smjese metan –vodik u cilindru za različita vremena bacanja iskre

In this study, numerical simulations of combustion characteristics using pure methane and 70 % CH4-30 % H2 blends were investigated in a spark ignition engine. The numerical calculations were performed using the finite volume CFD code FLUENT with standard k-ε model using the compression ratio and the engine speed are 10 and 2000 rpm respectively. Excess air ratios were selected as 1, 1.2 and 1.4. The spark timings were started at 45, 30 and 15 degree crank angle (CA) before top dead center (BTDC). The results of the combustion process were investigated as a function of crank angle. The maximum cylinder pressures and temperatures were obtained with 70 % CH4-30 % H2 mixture. It is observed that peak pressure values are decreased when the excess air ratio increased.U ovom se radu numerički simuliraju karakteristike izgaranja čistog metana i smjese 70 % CH4 i 30 % H2 kod motora paljenih sa svjećicom. Numerički proračuni su napravljeni koristeći kontrolni volumen CFD, kod FLUENT, sa standardnim k – ε modelom koristeći kompresijski omjer i brzinu motora 10 i 2000 min-1. Odabrani faktori pretička zraka su 1, 1.2 I 1.4. Vrijeme početka paljenja iskrom odgovaralo je 45, 30 i 15 stupnjeva koljenastog vratila prije gornje mrtve točke. Reultati procesa izgaranja su istraživani u ovisnosti o kutu pretpaljenja. Utvrđeni su maksimalni tlakovi u cilindru za smjesu 70 % CH4 i 30 % H2. Uočeno je da se smanjuju vrijednosti maksimalnog tlaka s povećavanjem faktora pretička zraka

Experimental investigation of the effect of spark plug gap on a hydrogen fueled SI engine

In this work, an experimental study on the performance and exhaust emissions of a commercial hydrogen fueled spark ignition engine (HFSIE) was performed at partially and full wide open throttle (50% and 100% WOT) positions. The engine is a four-stroke cycle six-cylinder, engine volume of 4.9 L, port fuel injection, hydrogen fueled SI engine with a bore of 102.1 mm, a stroke of 101.1 mm and a compression ratio of 13.5:1. The experiments were performed using 3 different spark plug gaps (SPG) (0.4, 0.6 and 0.8 mm), varied engine speeds of 1000-3000 rpm and two ignition timing values (10 and 15 degrees CA BTDC) at 50% and 100% wide open throttle (WOT). SPG is a factor affecting the performance of the engine depending on the engine structure. Maximum power values were obtained at 0.6 mm SPG for both 50% and 100% WOT at ignition timing values of 10 and 15 degrees CA BTDC. The maximum efficiency values were obtained with a 0.8 mm SPG at 50% WOT. At 100% WOT position, the maximum efficiency values were obtained with a 0.6 mm spark plug gap (SPG) at ignition timing values of 10 and 15 degrees CA BTDC. A significant decrease in NO emission was observed using hydrogen for all WOT and SPGs. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved

Combustion development in a gasoline-fueled spark ignition-controlled auto-ignition engine operated at different spark timings and intake air temperatures

WOS: 000507202700001Spark ignition-controlled auto-ignition is a combustion strategy to overcome the challenges in a homogeneous charge compression ignition or controlled auto-ignition combustion which has a limited operation region and does not have any direct control of the combustion timing. However, the spark ignition-controlled auto-ignition combustion can result in a large cyclic variability due to two main distinctive combustion phases developing initially by flame propagation and following controlled auto-ignition combustion throughout an engine cycle. Characterization of combustion development is, therefore, required to maintain a stable engine operation under spark ignition-controlled auto-ignition combustion. In this research, experimental studies were carried out to investigate spark ignition-controlled auto-ignition combustion development at different spark advances and intake air temperatures. Combustion analyses were performed employing pressure-based heat release and mass fraction burn curve to determine the main combustion parameters along with transition points (corresponding to crank angles) to controlled auto-ignition and mass fraction burnt by flame propagation. The results reveal that transition point has a strong correlation with crank angle position where 10% of fuel mass consumed combustion phasing rather than mass fraction burnt by flame propagation at the same intake air temperature. The cycles with a higher mass fraction burnt by flame propagation can result from early flame development at the advanced spark timings (at -30 and -40 degrees CA) while the slow flame development at a spark timing of -20 degrees CA due to late transition point corresponding to crank angle occurred. Besides, it is also found that flame propagation phase more contributes to the cyclic variation in the whole combustion process

Experimental investigation of performance and emissions of the SICAI-hybrid engine systems

The use of hybrid electrical engines can provide more efficiency by reducing fuel consumption and emissions. In the research, the experimental studies on the created hybrid electric engine were presented. The hybrid engine combines an electric motor with the internal combustion engine (ICE) which is operated under spark assisted controlled auto ignition (SICAI) combustion mode with the alternative fuels consisting of different ratios of methane hydrogen blends. In order to establish the hybrid engine, firstly, efficiency graphs of the electrical motor were obtained experimentally. The battery charge status was also checked. The operating range of the SICAI engine in the hybrid system was identified considering performance and efficiency parameters. Based on these parameters, a hybrid algorithm was established to control the operating of the created hybrid engine system. Thus, the experimental studies were carried out for 100% methane, 90% methane-10% hydrogen, 80% methane-20% hydrogen and, 70% methane-30% hydrogen blends (by volume) at wide opening throttle (WOT) and, 50% WOT positions. Consequently, the results were discussed in terms of efficiency and emissions. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved

Zero-dimensional single zone engine modeling of an SI engine fuelled with methane and methane-hydrogen blend using single and double Wiebe Function: A comparative study

Combustion modeling plays a key role in an engine simulation to predict in-cylinder pressure development and engine performance with a high level accuracy. Wiebe function, representing mass fraction burned (MFB) as a function of crank angle position, is widely used to predict the combustion process. The work presents a predictive zero dimensional (Zero-D) single zone engine modeling of an SI engine fuelled with methane and methane-hydrogen blend. In this work, the single and double forms of Wiebe function were used to estimate the combustion process in the modeling. For this purpose, the single and double-Wiebe functions' parameters were calculated using the least squares method by fitting to the MFB curves calculated from experimental pressure data. These Wiebe functions were, then, introduced to the Zero-D single zone engine model developed for the methane and methane-hydrogen blend fueled SI engine to obtain in-cylinder pressure development and gross indicated mean effective pressure (GIMEP) for the engine performance prediction. The results show that the model with double-Wiebe Function fit better than that with single-Wiebe function. In addition, the fitted double-Wiebe function has a significant improvement in the GIMEP prediction for methane-hydrogen blend fueled SI engine modeling rather than the methane-fueled modeling. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved

Parametric study on some combustion characteristics in a natural gas fueled dual plug SI engine

A parametric study on some combustion characteristics was carried out in a natural gas fueled dual plugs SI engine. Mass fraction burned, cylinder pressure histories and combustion durations of the engine were investigated by three equivalence ratio and spark advance for three spark plug configurations. It was found that equivalence ratio and spark plug configurations were more effective parameters on the total combustion duration than spark timing and was concluded that centrally located single plug configuration for equivalence ratio of 1.0 gives best combustion characteristics in compared to the other conditions. In addition, presented study showed that dual plugs serve an alternative for fast combustion in case of geometric constraints to use central location of the plug. (C) 2017 Elsevier Ltd. All rights reserved

PREDICTION OF PERFORMANCE AND EMISSION PARAMETERS OF AN SI ENGINE BY USING ARTIFICIAL NEURAL NETWORKS

This study deals with artificial neural network (ANN) modeling of a spark ignition engine to predict the engine performances and exhaust emissions of the engine. The proposed ANN model was solved by a developed computer program which was written in the Visual Basic programming language. For training and testing of the proposed ANN, a four-cylinder, four-stroke test engine were used to be fuelled by methane hydrogen blended with various percentages of hydrogen (0, 10, 20, and 30%), at different excess air ratios (0.9, 1, 1.1, 1.2, 1.3 and 1.4) and operated at different engine speeds (1500, 2000, 2500 and 3000 rpm). An ANN model based on standard back-propagation algorithm for the engine was developed using some of the experimental data for training. The used ANN has three layer, three cells in the input layer (Speed, H-2 and Excess air ratio) and 8 cells in the output lager (HC, CO, CO2, and O-2 emissions, torque, specific fuel consumption, power and exhaust temperature). The performance of the ANN was validated by comparing the prediction dataset with the experimental results. In the hidden layer, 28, 29, 30, 31 and 32 cells were tested with artificial neural network structures. Results showed that the ANN provided the best accuracy in modeling of the emission indices with correlation coefficient equal to 0.9880, 0.9728, 0.9930 and 0.9623 for CO, CO2, O2 and HC and 0.8650, 0.9840, 0.9252 and 0.9605 for torque, brake power, specific fuel consumption and exhaust temperature, respectively. The overall results show that the networks can be used as an alternative way for predicting the performance and emission parameters of SI engine. The best result was obtained in the ANN with 28 hidden cells (R2 = 0.9860)

Investigation of cylinder pressure for H2/CH4 mixtures at different loads

The purpose of this study is to experimentally analyze the performance and the pollutant emissions of a four-stroke spark-ignition engine operating on natural gas-hydrogen blends of 0%, 10%, 20% and 30% at full load and 65% load for different excess air ratios. This present work was carried out on a Ford engine. This is a four-stroke cycle four-cylinder spark-ignition engine with a bore × stroke of 80.6 × 88 mm and a compression ratio of 10:1. Experiments were made at a constant engine speed of 2000 rpm. CO, CO2 and HC emission values and cylinder pressures were measured. The results showed that while the excess air ratio increases, CO and CO2 emission values decrease. © 2009 International Association for Hydrogen Energy

Numerical analyses of combustion methane-hydrogen mixtures in cylinder for different spark timing

In this study, numerical simulations of combustion characteristics using pure methane and 70 % CH4-30 % H2 blends were investigated in a spark ignition engine. The numerical calculations were performed using the finite volume CFD code FLUENT with standard k-ε model using the compression ratio and the engine speed are 10 and 2000 rpm respectively. Excess air ratios were selected as 1, 1.2 and 1.4. The spark timings were started at 45, 30 and 15 degree crank angle (CA) before top dead center (BTDC). The results of the combustion process were investigated as a function of crank angle. The maximum cylinder pressures and temperatures were obtained with 70 % CH 4-30 % H2 mixture. It is observed that peak pressure values are decreased when the excess air ratio increased

Experimental study on a spark ignition engine fuelled by methane-hydrogen mixtures

In this study, effects on a spark ignition engine of mixtures of hydrogen and methane have been experimentally considered. This article presents the results of a four-cylinder engine test with mixtures of hydrogen in methane of 0, 10, 20 and 30% by volume. Experiments have been made varying the equivalence ratio. Equivalence ratios have been selected from 0.6 to 1.2. Each fuel has been investigated at 2000 rpm and constant load conditions. The result shows that NO emissions increase, HC, CO and CO2 emission values decrease and brake thermal efficiency (BTE) values increase with increasing hydrogen percentage. © 2007 International Association for Hydrogen Energy