SI Engine Research Articles

Flame propagation velocity in 2-stage gas combustion system applied in SI engine

Ever stronger emission standards accepted for modern internal combustion engines force some new tendencies in the engine development trends. In recent studies it was confirmed, that the use of combustion of lean gas-air mixtures leads to reduction of CO2 and HC emissions while maintaining a possible acceptable value of thermal efficiency. Such combustion systems, already known since many years as e.q. Turbulent Ignition, Pulsed Jet Combustion, Sparking Jet Ignition and similar, can offer further potential in the improvement of combustion process control. The main purpose of this research was to detect and define any correlation between gas delivery parameters, ignition energy in the first stage of combustion and some system design parameters with the turbulent ignition possibilities of lean and very lean gas mixtures, with the flame propagation velocity in main chamber and with the intensity of heat release. Such correlation should deliver some answers for the combustion system optimization and better combustion process control.For the above mentioned purpose the test stand with the model of IC engine was adopted. It delivered the possibilities of the spark-plug ignition in the prechamber and of the dynamic observation of the ignition spray propagation in main chamber of the system. For this last task the Rapid Compression Machine has been applied equipped with the optical access into main chamber and with high-speed recording system for dynamic registration of spray formation as well as for flame propagation across the chamber. Simultaneously performed indication of both chambers (pre-chamber and main chamber) made it possible to correlate of indexes determined for flame propagation velocity, flame luminosity distribution in main chamber with thermodynamic indexes achieved form the analysis of the pressures, temperatures and mixture masses in both chambers.The results achieved within this research allow to identify many design parameters of the 2-stage combustion system and to recognize more important thermodynamic parameters of the system which seems to be essential for improving of the system potential according heat release, heat release rate and system thermal efficiency for the future development.

Analysis of particle mass and number emission from an SI engine with direct fuel injection and a particulate filter

Direct fuel injection engines have dominated the market for passenger cars powered with gasoline. They are characterized by reduced fuel consumption and higher unit power and torque. The reduction of the time needed for fuel evaporation is associated with an increase in mass emission, and above all the number of solid particles in comparison to systems in which a multipoint injection is used. To minimize the negative effects of the applied solution, in September 2017 the EURO 6c standard was introduced, which apart from the mass also limited the road emission of the particle number. The article presents the mass and number emission and particle size distribution tests results for an engine with and without a particulate filter. The tests were carried out in simulated real conditions on a dynamic engine dynamometer station.

Experimental Investigation of Using Ethanol-Gasoline in Spark Ignition Engine

The consequence of mixing pure ethanol with gasoline on the pollution and performance of SI engine are investigated experimentally in the existent study. The SI engine that employed in the experiment is a single cylinder four stroke. Analysis is carried out for engine operation parameter, CO2, CO and unburned HC productions. The measurements are recorded for several engine speeds from 1500 – 3000 rpm with load and ethanol addition of (0E, 10E, 20E, 30E, 40E, 50E,). The results displayed increasing in brake power, and brake thermal efficiency while the brake specific fuel consumption decreases when the ethanol- gasoline blends fuel increases. Also it was found that CO, HC, and CO2 concentrations decrease when the ethanol- gasoline increases. The best results obtained in the study is for the blend of E-50.

Combustion and Emissions of a Small SI Engine with Buthanol Blend Fuels

The bioalcohols are an important alternative in the general efforts to replace the fossil fuels in transportation by renewable fuels. The global share of Bioethanol used for transportation is continuously increasing. Butanol, a four-carbon alcohol, is considered in the last years as an interesting alternative fuel, both for Diesel and for Gasoline application. Its advantages for engine operation are: good miscibility with gasoline and diesel fuels, higher calorific value than Ethanol, lower hygroscopicity, lower corrosivity and possibility of replacing aviation fuels. In the present work research with different Butanol portions in gasoline (BuXX) was performed on the 2-cylinder SI engine with variations of several parameters on engine dynamometer. In the steady state operation, it was found that Bu-blends generally reduce the emissions of CO, HC, NOx in untreated exhaust gas and have a very little influence on catalytic conversion rates of the 3-way-catalyst. At lower engine part load, “Bu” shortens the inflammation lag and reduces the cyclic dispersion of combustion. Nevertheless, this advantage disappears at higher engine loads and with higher “Bu” portions.The present paper shows some examples of the most important results.

Harmful deposits in reciprocating internal combustion engines – methods of assessment and scope of application

The deposits forming on the surfaces of various internal parts of reciprocating internal combustion engines and the systems operating in conjunction with them are an undesirable phenomenon which intensifies during the operation of the engines and threatens their proper operation. More and more complicated engine designs and the increasing accuracy of workmanship of the parts working in conjunction with them necessitate the multi-directional testing of harmful deposits. An increasing number of factors affecting deposit formation are being identified, which leads to the development of increasingly complex classifications and subdivisions of deposits according to their type, composition, and form. The article presents the problems of the deposits produced in reciprocating internal combustion engines and their fuel systems. Standard and non-standard engine and analytical methods for both quantitative and qualitative assessment of deposits are discussed. The significance of currently applied assessment methods for the formation of deposit classification is presented. The paper presents the scope of application and usefulness of methods for the determination of the threats posed by various types of deposits to the functioning of the engine and for the identification of the causes for their formation, including in particular those related to the composition of fuels and engine lubricating oils used. A practical approach to the quantitative and qualitative assessments of deposits is discussed on the examples of engine, microscopic and spectral test assessments of real deposits produced on various elements of SI and CI engines and their fuel systems, including both the fuel supply systems using hydrocarbon fuels and those using fuels containing biocomponents.

Investigation of Knock Suppression Characteristics in a Boosted Methane – Gasoline Blended Fuelled SI Engine

Investigation of Knock Suppression Characteristics in a Boosted Methane – Gasoline Blended Fuelled SI Engine

Thermodynamic operating indicators of an SI engine with a rate-shaping type direct injection

The authors proposed a rate-shaping injection consisting of a time-controlled fuel dosing to allow better control of the injection process and also of the combustion process as a final result. The effects evaluation of applying such fuel injection control method should be based on the obtained engine operating indicators improvement analysis, especially the thermodynamic indicators. Selected injection strategies were implemented in an experimental engine model – a rapid compression machine (RCM). The observations of the processes inside the cylinder were carried out at the frequency of 10 kHz using the high speed camera. Indicator tests (AVL IndiModul) were performed with the same data acquisition frequency for further synchronization with the optical tests results. Comparative analyses of the effects of the direct injection system with a single fuel dose and rate-shaping system were performed. Combustion rates influencing the process thermodynamic indexes and resulting in differences in the results of optical tests were experimentally determined. The comparative assessment of the obtained results and analyses lead to the conclusion that the use of the rate-shaping system enables a significant increase in the combustion process control and enables the injection process control methods to be correlated with the operational indices of the model engine.

Research of operating and ecological parameters of the SI engine fed by different fuel types

The purpose of the research is to evaluate the operational and ecological parameters of an engine fed by various types of fuel. The test stand constructed for this purpose was prepared to evaluate the engine work indicators for eight different types of motor gasolines from different manufacturers and with different octane number. The tests were performed on a Fiat 170A1 engine. Parameters that were measured directly in the test were: rotational speed, torque, fuel consumption, exhaust gas temperature, run of indicated pressure. The conducted research and comparative analysis of the obtained results confirmed that the type of fuel used does not significantly affect the obtained values of ecological and operating parameters. The higher fuel octane number with the compression ratio used in the research engine did not affect the higher values of the measured parameters.

In-Cylinder Combustion Analysis of a SI Engine Fuelled with Hydrogen Enriched Compressed Natural Gas (HCNG): Engine Performance, Efficiency and Emissions

In-Cylinder Combustion Analysis of a SI Engine Fuelled with Hydrogen Enriched Compressed Natural Gas (HCNG): Engine Performance, Efficiency and Emissions

Evaluation on physicochemical properties of iso-butanol additives in ethanol-gasoline blend on performance and emission characteristics of a spark-ignition engine

In this study, experiments were conducted on a four-cylinder spark-ignition engine to investigate the effects of iso-butanol additives in ethanol-gasoline blend on fuel properties, performance and emission characteristics of a SI engine. The engine tests were carried out at 50% wide open throttle and variations of engine speed from 3000 to 5000 RPM with an interval of 1000 RPM. The engine was fueled with base gasoline fuel, ethanol-gasoline blended fuel at 10% volume percentage of ethanol (E10) and three different fuel blends of iso-butanol additives; 5%, 10% and 15%, in E10 blended fuel denoted as E10B5, E10B10 and E10B15, respectively. Physicochemical properties tests were conducted in this study to evaluate the fuel heating value, kinematic viscosity and density, which have been selected due to their influences on engine performance and exhaust emissions. Results of heating value showed a decreasing pattern for the blended fuel samples compared with that of base gasoline fuel as E10, E10B5, E10B10 and E10B15 produced 2.33%, 3.14%, 5.06%, and 5.31%, respectively. However, as alcohol concentration increases in the blended fuel samples, the density and kinematic viscosity were both increased with maximum values of 0.767 g/cm3 and 1.15 mm2/s, respectively obtained for E10B15. In terms of engine performance, the blended fuel samples exhibited higher brake power than that of base gasoline fuel with mean increase of 7.71%, 10.21%, 10.89% and 11.54% for E10, E10B5, E10B10 and E10B15, respectively. Significant reduction in brake specific fuel consumption obtained with E10, E10B5, E10B10 and E10B15 by mean of 3.57%, 5.15%, 7.14% and 10.89% respectively, compared to base gasoline fuel. Noticeable improvement of brake thermal efficiency observed with the blended fuel at a maximum increment of 18.91% achieved by E10B15. High combustion temperature produced by the blended fuel samples have been contributed to the higher exhaust gas temperature. Accordingly, the emissions of carbon monoxide and hydrocarbon were all reduced; except for carbon dioxide and nitrogen oxide, with the addition of iso-butanol additive compared to those of ethanol-gasoline blend and base gasoline fuel.

Optimization of Fuel Consumption of a SI Engine Using Variable Valve Timing and Variable Length Intake Manifold Techniques

According to the world crisis about fuel consumption and environmental concerns regarding toxic emissions of internal combustion engines, the engines with higher efficiency and lower fuel consumption have been a topic of research in last decades. In this study, variable valve timing (VVT) and variable length intake manifold (VLIM) techniques are used to optimize the fuel consumption of an SI engine. At first, all components of engine are modeled in GT-POWER and a comparison with experimental results is performed to confirm the accuracy of the model. Then, the discrete-gird algorithm is employed to optimize the parameters in GT-POWER. The results obtained indicate that optimal valve timing and intake manifold length significantly reduces brake specific fuel consumption (BSFC).

Octane number stratified mixture preparation by gasoline–ethanol dual injection in SI engines

High octane number is one of the attractive properties of ethanol. Appropriate distribution of ethanol vapor concentrations in combustion chamber at the end of the compression process could suppress engine knock phenomena and hence improve performance and reduce pollutants emission of spark ignition engines fueled with gasoline–ethanol. This paper presents numerical simulation results of a new concept of octane number stratified charge mixture via dual injection of ethanol and gasoline. The principle of the concept is the optimization of fuel vapor concentrations distribution in combustion chamber to ensure high ethanol concentrations in zone risk of knock. Two dual-injection schemas have been studied: (1) port inject of gasoline and direct injection of ethanol and (2) separate port injection of gasoline and ethanol through two opposite intake manifolds. In the first case, direct injection of ethanol in axial direction did not result in ethanol concentration stratification. Stratification occurred when direct injection of ethanol in radial direction started later than port injection of gasoline. In the second case, significant stratification of ethanol concentrations occurred when ethanol injection started earlier than gasoline injection. In the combustion chamber, high ethanol concentration was found near the ethanol injection inlet port, whereas high equivalence ratio was found in the opposite side. Thus, the location of the spark plug in the opposite side of ethanol injector is optimal for improving anti-knock performance of engine fueled with ethanol gasoline at a given fuel ratio.

Analysis and Simulation of Non-Flamelet Turbulent Combustion in a Research Optical Engine

In recent years, the research community devoted many resources to define accurate methodologies to model the real physics behind turbulent combustion. Such effort aims at reducing the need for case-by-case calibration in internal combustion engine simulations. In the present work two of the most widespread combustion models in the engine modelling community are compared, namely ECFM-3Z and G-equation. The interaction of turbulent flows with combustion chemistry is investigated and understood. In particular, the heat release rate characterizing combustion, and therefore the identification of a flame front, is analysed based on flame surface density concept rather than algebraic correlations for turbulent burn rate.In the first part, spark-ignition (S.I.) combustion is simulated in an optically accessible GDI single-cylinder research engine in firing conditions. The turbulent combustion regime is mapped on the Borghi-Peters diagram for all the conditions experienced by the engine flame, and the consistency of the two combustion models is critically analysed.In the second part, a simple test case is defined to test the two combustion models in an ideally turbulence-controlled environment: this allows to fully understand the main differences between the two combustion models under well-monitored conditions. and results are compared against experimental databases of turbulent burn rate for wide ranges of Damkohler (Da) and Karlovitz (Ka) numbers.The joint experimental and numerical study presented in this paper evaluates different approaches within the unified flamelet/non-flamelet framework for modelling turbulent combustion in SI engines. It also indicates guidelines for reduced calibration effort in widespread combustion models.

Emissions analysis of an SI engine with humidified air induction

In this experimental research, the effects of humidified air induction on emissions of an SI engine have been investigated. Experiments have been performed on four-stroke SI engine fuelled with unleaded gasoline at two loads (50 % and 100 %) and four engine speeds (1200, 1400, 1600 and 1800 rpm) for 35 % and 80 % relative humidity. The experiments were first made with 35 % humid air, then the relative humidity of the intake air was increased 80 % with water injection and the same experiments were repeated. Exhaust emissions such as NOx, CO, HC and CO2 were measured and compared for each test condition. The results show that enhancement the relative humidity of the inducted air from 35 % to 80 % reduced the NOx, CO2, CO and HC emissions at full engine load with an improvement in brake thermal efficiency.

Approaches and solutions to HCCI - a review energy systems: fuel and combustion, injection and atomization

SI and CI engines are entities in which conditions of internal combustion was triumphantly implemented. In a gasoline engine both efficiency and emissions are less; on the other hand in a diesel engine both are relatively high. It is hard to achieve a win-win situation where fuel consumption and adverse impact on the environment were diminished. Over the past few decades researchers have assigned themselves to strike a balance in this regard, creating Homogeneous charge compression ignition engine technology, which perfectly amalgamates the principles of Spark Ignition and Compression Ignition engines, making it the holy grail of engines. Homogeneous charge compression ignition engines do not employ spark plug or fuel injector to initiate combustion, the lean homogeneous mixture auto-ignites in multitudinous spots once it is compressed to attain its chemical activation energy. Unlike its contemporaries the combustion is flameless, propelled the fuel efficiency along with an enormous decrease in emissions. This proposed work digs deep into conceptual description of the fundamentals of HCCI engine and various approaches to attain HCCI, along with the challenges encountered related to the same being elaborated. Depending on inferences arrived from the challenges different controlling strategies are proposed in this paper.

Effect of bioethanol blending with gasoline on emissions characteristics with spark plug alteration for SI engine

Effect of bioethanol blending with gasoline on emissions characteristics with spark plug alteration for SI engine

Combustion performance of dual-injection using n-butanol direct-injection and gasoline port fuel-injection in a SI engine

In this study, combustion performance of dual-injection using n-butanol direct-injection (DI) and gasoline port fuel-injection (PFI) was evaluated. Dual-injection with various mass fraction of gasoline PFI and n-butanol DI were examined in a single cylinder SI engine operating at 1500 r/min, wide-open-throttle and stoichiometric air-fuel ratio (λ = 1). Indicated mean effective pressure (IMEP), knock behaviors, cylinder pressure and fuel consumption performance of dual-injection were compared with those of gasoline single-injection. At maximum brake torque (MBT) spark timings, dual-injections can produce higher engine IMEP when compared with gasoline PFI single-injection. Due to the increased engine IMEPs, dual-injections of 80% gasoline PFI-20% n-butanol DI (G80B20) and 50% gasoline PFI-50% n-butanol DI (G50B50) exhibited higher knock propensity and heavier knock intensity. When the mass fraction ratio of n-butanol DI reached to 80%, in-cylinder cooling effects of n-butanol vaporization dominated and led to a decrease of knock occurrence. Through in-cylinder pressure measurement, relatively high maximum combustion pressure with earlier crank angle were observed under dual-injection modes. Increase of the mass fraction of n-butanol DI, dual-injections resulted in higher fuel consumption rates. Nevertheless, comparisons of the indicated specific energy consumption rates of each injection mode indicated that n-butanol gasoline dual-injection had superior fuel conversion efficiencies.

Experimental and artificial neural network (ANN) study of hydrogen enriched compressed natural gas (HCNG) engine under various ignition timings and excess air ratios

In today's era, the computational capabilities of artificial neural network has endorsed to be a bedrock and inferences in many fields, including internal-combustion engines. The presented research in ANN has been germinated to anticipate the performance and emission characteristics of a turbocharged SI engine fueled with various HCNG mixtures. The experiments were accomplished at various excess air ratios (λ), ignition timings (θi) at MAP of 105 kPa and 140 kPa, while engine speed was kept constant at 1600 rpm to obtain data for testing and training ANN model. The test results show that with the increase in values of λ, MAP, and hydrogen addition, the torque output effectively decreases while BSFC first decreases and after attaining minimum value it further increases. The NOx, CO, THC, and CH4 emissions all declined with the hike of ignition advance angle, and inclined with increase of the load. ANN’s popular backpropagation algorithm is adopted in multilayered feedforward networks. In order to predict the performance and emission characteristics of HCNG engine, the four-input and one-output network structure are used. HCNG0, HCNG20 and HCNG40 blends has been studied in the presented ANN model in which the excess air ratio (λ), engine load, ignition timing, and HCNG blends has been taken as four-input parameters. The bestowed model has been trained using hyperbolic tangent transfer activation function (tansig) and Levenberg-Marquardt learning algorithm (LM) along with numerous neurons.The lowest and highest value of correlation coefficient (R) and mean square errors (MSE) for validation were dig-out for various parameters, which were BSFC, torque, NOx, CO, THC, CH4. The values of R (min–max) and MSE (min–max) were BSFC; 09519–0.9963 and 5.72–64.29, torque; 0.9948–0.9997 and 8.3935–95.8350, NOx; 0.9938–0.9992 and 0.5271–3.4340, CO; 0.8595–0.9960 and 0.0188–1.0154, and THC; 0.9644–0.9972 and 0.0714–1.1695, CH4; 0.7965–0.9973, 0.0351–1.1789 respectively for various number of neurons. This research work provides the gist of ANN as an attractive choice to researchers for classical modelling techniques. In this regard, the ANN modeling can be utilized to minutely predict the performance and emission characteristics of hydrogen added CNG engines.

ELECTRICITY GENERATED BY ALTERNATIVE BIOFUEL PRODUCTED FROM AGRICULTURAL WASTE

Egypt still depends largely on petrol and diesel to run internal combustion engines with its attendant problems of scarcity, pollution of the environment, and contribution to global warming, and cost. The aim of the current research is the ability to apply the biofuel produced from agriculture waste bioethanol and biogas to generate the electricity by operating the two stroke Gasoline Generator. The bio-ethanol produced from the potato’s wests in 2014, Faculty of agriculture, Kafrelsheikh University was mixed with Gasoline fuel to obtain the three different percentage 0%, 20 % and 50%. As well as the study included that the ability to produce the biogas. The biogas production unit consists of main reactor tank from plastic with capacity 1000 L fixed at ground and the collecting gas tank put into the top of main reactor tank. The gasoline with octane 80 was used as a control fuel at two different throttle fuel positions. The main treatment were the two bioethanol fuel E20 (20 %) and E50 (50%) to test at half and full open throttle valve compared to application of biogas to generate the electricity at full open fuel throttle valve. Bachrach Fylite Insight Plus ® model 374 analyzer is used to measure the exhaust gases. This current research will discuss the potentials, obstacles and necessary framework conditions for the utilization of biogas for small scale electricity generation in Egypt. The results showed that the bioethanol and biogas may able to operate two stroke SI engine. It is clearly that, the electrical energy decreases when the ethanol was added to the Gasoline fuel Oct. Nr. 80 at full and half throttle position. The electrical power for gasoline Oct.Nr.80 fuel was 720 W compared to 680 W, 540 W and 320 W for E20 and E50 bioethanol fuel and biogas respectively at full throttle position. Also the maximum electrical power generated from biogas was 332.6 W for around 57 min operating time/day. The percentage of the CO2 in exhaust gases were 9.1 %, 7.3 %, 5.9 % and 4.2 % for gasoline Oct.Nr.80 fuel, bioethanol E20, E50 and biogas respectively at full throttle position. The biogas may be reducing the exhaust gases emissions of the CO and CO2 compared with the Gasoline fuel and bioethanol E20, E50 blend fuel.

The influence of exhaust system leak on the operating parameters of a turbocharged spark ignition engine

Turbocharging of an internal combustion engine is the most common technique to improve an engines’ performance. In present it is not hard to meet vehicles on the road with turbocharged SI engines, which have a high mileage, and because of this fact there is a high risk of exhaust systems leak. This might have its influence not only on the emissions, but also on the vehicles performance. Thereby this dissertation shows the comparative analysis of the influence of exhaust system leak in the catalyzer input on the exhaust gasses composition in the catalyzer output and the operation parameters of an turbocharged SI engine. During the research some parameters were recorded and compared, e. g.: the engines power and torque, the injec-tors opening time, the oxygen sensors voltage signals in the input and in the output of the catalyzer, the concentration of harmful gasses in the exhaust tailpipe. The research was conducted with the use of a single roller MAHA MSR 500 chassis dynamometer. A series of torque measurements was performed. Under these measurements a simulation of the exhaust system leakage of a turbocharged SI passenger car engine was made. As a result three variations of the wideband oxygen sensor acting were reached. The wideband sensor is mounted between the turbocharger unit and the input of the catalyzer. In the test the influence of the leakage on the injector’s opening time and the composition of harmful exhaust substances were pointed.