Four-stroke Spark Ignition Engine Research Articles

Experimental Study of the Effect of a Non-Oxygenated Additive on Spark-Ignition Engine Performance and Pollutant Emissions

In this study, effects of adding butene, homopolymer to gasoline on the performance of a four-stroke spark ignition (SI) engine and pollutant emissions have been investigated. This additive increases the octane number of gasoline. In this research, the additive was combined with a non-leaded gasoline. Also, in addition to fuel changes and the use of additives, engine spark plugs were replaced and three types of spark plugs were used for this study. These include single electrode spark plug, dual electrode spark plug and Platinum+4 spark plug. The results of experimental tests showed that with the addition of additive to gasoline, the brake torque and braking power were increased with the use of each of the three spark plug type. The results revealed that by combining gasoline and additive, carbon dioxide and nitrogen oxides emissions were increased. On the other hand, unburned hydrocarbons and carbon monoxide emissions from the engine were reduced. In addition, it was concluded that changing the spark plugs had slight effect on engine performance and pollutant emissions, and that the results of experimental tests using all three types of spark plugs were almost identical.

Experimental investigation on four-stroke catalytic coated spark ignition engine to promote cleaner environment

In the present scenario, automobile manufacturing industries face challenges in marketing vehicles with internal combustion (IC) engine to customers due to strict government regulation on emission norms and customers expectation on better engine performance. Hence, it is very important to identify some technique to reduce the emission level and also to improve the engine performance. The catalytic coating is one of the most suitable techniques for reduction of pollution level and increasing the engine performance. In this paper, the outcomes of investigations carried out on the emission control and engine performance of catalytic coated single cylinder four-stroke spark ignition (SI) engine is discussed in detail. The engine combustion chamber and piston crown were coated with copper (catalyst). The performance parameters of catalytic coated engine such as torque, brake power at different engine speed and load conditions were measured using two-wheeler chassis dynamometer. In this investigation, a comparative study was also done in parallel with conventional (un-coated) SI engine. The results showed that copper coated engine has significantly reduced levels of carbon monoxide (CO), hydrocarbon (HC) and carbon dioxide (CO2) emission compared to conventional engine (un-coated).

Acoustic performance and modal analysis for the muffler of a four-stroke three-cylinder inline spark ignition engine

Acoustic performance and modal analysis for the muffler of a four-stroke three-cylinder inline spark ignition engine

Optimization of four stroke spark ignition engine for firesport

The effort of engineers is to achieve the highest possible power from the engine of a given size, in other words, to improve the weight - power ratio. This must be achieved while maintaining other parameters such as service life, emissions, fuel consumption, and others. Engine power is (simply put) given by the amount of air supplied to the combustion process. From this point of view, there are two ways to increase engine power: engine overcharging or improving the hydraulic conditions of the intake and exhaust system. This paper describes the second way - modifications of the four-stroke spark-ignition engine, which lead to engine power increase. Outputs using laboratory measurements have been verified. In addition, an engine model in Lotus Engine Simulation software has been created. The paper deals with the effect of some engine adjustments on the power: modification of valve shapes, modification of intake and exhaust ports, and camshaft modification. The described engine is mainly used in firesport, which is one of the most popular sport disciplines in the Czech Republic and in Slovakia. All adjustments are designed so that the modified engine meets the rules for firesport. Due to the fact that the assessed engine for sports industry has been used, neither fuel consumption nor emissions have been monitored.

Effects of Propanol and Camphor Blended with Gasoline Fuel on the Performance and Emissions of a Spark Ignition Engine.

In this research, the performance and emissions of a four-stroke spark ignition engine fuelled with varying proportion of propanol-camphor and gasoline blends were investigated. The physicochemical properties such as specific gravity, viscosity, fire point, flash point, and iodine value (I.V.) of the blends were determined, and the values obtained conform to the ASTM standard. Sample P0B (100% of pure gasoline and 5 g of camphor) had the best physicochemical property values higher than those of the least sample of P15B by the following percentages: specific gravity (0.5%), viscosity (30.8%), fire point (5.08%), flash point (21.8%), and I.V. sample (0.5%). Also, the engine performance parameters such as brake power, brake thermal efficiency, brake mean effective pressure (BMEP), and specific fuel consumption were generated from the engine-measured parameters. Sample P0B has the best specific fuel consumption for the torque of 3 N m with a value of 22.77 kg/kW h, and sample P0A (100% of pure gasoline) has the best fuel consumption for a torque of 6 N m with a value of 12.52 kg/kW h. For brake thermal efficiency, sample P0B gives the best brake thermal efficiency at the two constant torques with a value of 0.36 for torque 3 N m and 0.67 for torque 6 N m. Sample P15C (85% of gasoline, 15% of propanol, and 5 g of camphor) gives the best BMEP at torque 3 N m with a value of 1.92 bar, and sample P5C (95% of gasoline, 5% of propanol, and 10 g of camphor) gives the best BMEP at 6 N m with a value of 3.85 bar. Exhaust emissions were analyzed for unburned hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO2), and nitrogen oxide (NOx). The results showed that increasing the blending percentage reduces the emitted concentration of CO, HC, and NOx. Carbon monoxide emission was found to be lowest at sample P10A (90% of gasoline and 10% of propanol) for torque 3 N m with a value of 0.16, and at torque 6 N m, the sample with the lowest percentage was P15C with a percentage of 0.21.

Investigation of cycle-to-cycle variations in a spark-ignition engine based on a machine learning analysis of the early flame kernel

High-speed Mie scatter imaging and in-cylinder pressure measurements are performed in an optically accessible four-stroke spark-ignition engine to investigate cycle-to-cycle variations (CCVs). Droplet Mie scattering is used to measure the cross-sectional flame contour. Machine learning (ML) methods are applied to predict combustion cycles of high maximum in-cylinder pressure based on flame cross-sections at -15 °CA (crank angle degrees before top dead center). All tested ML methods (decision tree-based, multi-layer perceptron, and logistic regression) are able to predict high energy engine cycles given only partial flame topology information at a temporal snapshot of the flame propagation. Feature importance analyses, employed using decision tree methods, reveal that a combination of flame position and shape features of the flames' cross-section is necessary in achieving a high prediction accuracy. These sensitivity analyses can be used to gain insight into the combustion processes and to strategically reduce the number of features. This enables the addition of new physical quantities in future investigations.

Potentiality of Saccharomyces Boulardii in Fermentation of Bio-Ethanol Derived from Fruit Wastes

An astronomical increase in vehicular usage has led to the depletion of existing fossil fuels and forced researchers to find alternative sources of fuels. Extensive studies are utilizing Saccharomyces cerevisiae for bioethanol production. Therefore, in the present study, the potential application of Saccharomyces boulardii derived bioethanol from fruit wastes was explored. The orange, sweet lime, and banana peels were subjected to various pre-treatment procedures and used as substrates for yeast mediated fermentation. The cellulosic de-linearization of fruit peels induced by alkaline and steam pre-treatments was analysed using Fourier Transform Infrared Spectroscopic analysis. The chemical nature of fruit waste-derived bioethanol was compared with commercial ethanol using gas chromatographic analysis. Bioethanol used in ratios 0%, 4%, 8%, 12% by volume as part of fuel blends were subjected to performance testing. This testing process was carried out on a single-cylinder, four-stroke spark-ignition engine and the effect of bioethanol content (by volume) on the operational parameters like total fuel consumption, brake specific fuel consumption, brake thermal efficiency, volumetric efficiency, and equivalence ratios were assessed. FTIR spectra showed significant changes in the chemical structure of fruit peels due to pretreatments. The bioethanol yields increased up to 24 h of fermentation after which there was a steady decline. These results were confirmed by an increase in pH of the biomass after 24 h up to 72 h. Enzymatic hydrolysis of fruit peels resulted in higher bioethanol yield as compared to acid treatment. The fruit derived bioethanol showed ideal physicochemical characteristics for use as automobile fuel. The same showed decent performance when tested on a four-stroke, spark ignition engine

Influence of Compression Ratio on Flywheel Dimension for a Naturally Aspirated Spark Ignition Engine: A Numerical Study

The proper design of the flywheel undeniably determines in tuning the engine to confirm the better output engine performance. The aim of this study is to mathematically investigate the effect of various values of the compression ratio on some essential parameters to determine the appropriate value for the flywheel dimension. A numerical calculation approach was proposed to eventually determine the dimension of the engine flywheel on a five-cylinder four-stroke Spark Ignition (SI) engine. The various compression ratios of 8.5, 9, 9.5, 10, 10.5, and 11 were selected to perform the calculations. The effects of compression ratio on effective pressure, indicated mean effective pressure (IMEP), dynamic irregularity value of the crankshaft, and the diameter of the flywheel was clearly investigated. The study found that 2.5 increment value of the compression ratio significantly increases the effective pressure of about 41.53% on the starting of the expansion stroke. While at the end of the compression stroke, the rise of effective pressure is about 76.67%, and the changes in dynamic irregularity merely increase by about 1.79%. The same trend applies to the flywheel diameter and width, which increases 2.08% for both.

Development of a Marine Two-Stroke Diesel Engine MVEM with In-Cylinder Pressure Trace Predictive Capability and a Novel Compressor Model

In this article, to meet the requirements of marine engine room simulator on both the simulation speed and simulation accuracy, a mean value engine model (MVEM) for the 7S80ME-C9.2 marine two-stroke diesel engine was developed and validated in the MATLAB/Simulink environment. In consideration of the significant influence of turbocharger compressor on both the engine steady state performance and transient response, a novel compressor model (mass flow rate and isentropic efficiency model) based on a previous study carried out by the first author was proposed with the aim of achieving satisfactory simulation accuracy within the whole engine operating envelope. The predictive and extrapolative capability of the proposed compressor model was validated by carrying out simulation experiments and analyzing the simulation results under steady state condition and during transient process. To make the traditional MVEM capable of predicting in-cylinder pressure trace, the cylinder pressure analytic model proposed by Eriksson and Andersson for the four-stroke SI (spark ignition) engine was adapted to the 7S80ME-C9.2 marine two-stroke diesel engine based on the characteristic of in-cylinder pressure trace of this type of engine and then coupled to the MVEM developed in this paper. Since there is no need to solve any differential equation as it is done in the 0-D model, the advantage of MVEM in running speed is not impaired. For achieving satisfactory simulation accuracy by using the analytic model, the model parameters were calibrated elaborately by using engine measured data and a 0-D model and the relevant tuning procedure was discussed in detail.

Comparative Study of the Effective Release Energy, Residual Gas Fraction, and Emission Characteristics with Various Valve Port Diameter-Bore Ratios (VPD/B) of a Four-Stroke Spark Ignition Engine

In this research, the residual gas, peak firing pressure increase, and effective release energy were completely investigated. To obtain this target, the experimental system is installed with a dynamo system and a simulation model was setup. Through combined experimental and simulation methods, the drawbacks of the hardware optimization method were eliminated. The results of the research show that the valve port diameter-bore ratio (VPD/B) has a significant effect on the residual gas, peak firing pressure increase, and effective release energy of a four-stroke spark ignition engine. In this research, the engine was performed at 3000 rpm and full load condition. Following increased IPD/B ratio of 0.3–0.5. The intake port and exhaust port diameter has a contrary effect on engine volumetric efficiency, the residual gas ratio increase 27.3% with larger intake port and decrease 18.6% with larger exhaust port. The engine will perform optimal thermal efficiency when the trapped residual gas fraction ratio is from 13% to 14%. The maximum effective release energy was 0.45 kJ at 0.4 intake port-bore ratio, and 0.451 kJ at 0.35 exhaust port-bore ratio. The NOx emission increases until achieved a maximum value after that decrease even VPD/B was still increasing. With a VPD/B ratio of 0.35 to 0.4, the engine works without the misfiring.

Experimental research on ethyl acetate as novel oxygenated fuel in the spark-ignition (SI) engine

ABSTRACT It is known that blending oxygenated fuels to gasoline can increase knock resistance of the fuel and reduce exhaust emissions. In this experimental research, ethyl acetate as a new and renewable oxygenated fuel which is produced through the reaction of ethanol with acetic acid was added to base gasoline at 5% (E5) and 10% (E10) volume ratios to investigate its effect on engine performance and exhaust emissions. For this, a single-cylinder and four-stroke SI engine was utilized, and engine experiments were carried out under low, medium, high and full load at a constant engine speed of 1500 rpm. The potential for the ethyl acetate as oxygenated fuel was also further investigated by distillation tests. In addition, a fuel cost analysis based on brake specific fuel consumption and fuel price was performed. Results revealed that E5 and E10 displayed superiors in terms of CO and HC emissions to base gasoline. It was determined that oxygen content in ethyl acetate led to decrease in CO and HC emissions by 54.5% and 50.1%, respectively. However, NOX emissions dramatically increased by 81.1% with fuel blends operation and engine performance parameters such as brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) deteriorated. Furthermore, the fuel economy analysis showed that 5 vol.% and 10 vol.% ethyl acetate blends with base gasoline presented averagely 38.9% and 84.5% higher fuel cost relative to gasoline.

Effect of wash coat layers on the conversion efficiency of a catalytic converter in the SI engine

The present work deals with the effect of different wash coat layers such as micro alumina, nano alumina and yttria on the reduction of HC, CO emissions when compared to base line emissions. The morphology of various wash coat materials was characterised by means of a scanning electron microscope. The experimental investigations were carried out in a four-stroke spark ignition engine before and after ageing of catalytic converters. The decrease in HC and CO emissions was found to be in the order of nano alumina, yttria dual and micro alumina when compared to base line readings before ageing. The decreases in HC and CO emissions were found to be in the order of yttria dual, nano alumina and micro alumina when compared to base line readings after ageing. The maximum conversion of yttria dual can be attributed to the adhesion properties of the wash coat with the substrate.

Energy and exergy analyses of a hydrogen fueled SI engine: Effect of ignition timing and compression ratio

In the current study energy and exergy analyses of a hydrogen fueled four-stroke spark ignition engine are presented. The energy and exergy analyses are performed based on experimental results conducted on single cylinder, air cooled SI engine which is operated four different compression ratios (ε = 6.6, 7.1 7.6 and 8.1) seven different spark ignition timing, 1600 rpm constant engine speed, lean mixture (ϕ = 0.6) and wide-open throttle conditions. The experimental results, energy and exergy analyses showed that the increase in compression ratio yields an increase in indicated and effective performance parameters of the engine while decrease in exergy destruction is observed. However, the move away of the ignition timing from the optimum value (over or retarded ignition timing) leads to a reduction in engine performance parameters and rise in exergy destruction. Another noteworthy result of this study is that the values of both indicated and effective thermal efficiencies obtained based on experimental studies and the values of both indicated and effective exergy efficiencies obtained by thermodynamic analyses are very close to each other.

Experimental study on knock suppression of spark-ignition engine fuelled with kerosene via water injection

The four-stroke spark-ignition (SI) internal combustion engine has good fuel economy and high power/weight ratio, making it very suitable for small aircraft. Normally, four-stroke aviation SI engines are fuelled with gasoline. Using kerosene can improve the system safety; However, a four-stroke SI engine fuelled with kerosene suffers from a small indicated mean effective pressure (IMEP) because of the knock limit of kerosene. In this study, water injection is investigated as a method of extending the knock limitation and improving IMEP of a four-stroke SI engine fuelled with kerosene. First, a Rotax 914 engine is retrofitted. Two port-fuel-injection systems supplied with kerosene and water are developed. Then, the combustion characteristics with water injection are studied. The effects of water injection on the in-cylinder pressure and heat-release rate are analysed. Additionally, the extent of knock suppression due to water injection under various engine speeds is evaluated. The results indicate that the knock limit of the four-stroke SI engine with kerosene is extended significantly via water injection. The measured IMEP is improved by 25–28% under different engine speeds. Thus, the requirement for ordinary cruise operation is satisfied. Furthermore, the security is enhanced with water injection.

Computational Investigation of Porous Media Combustion Technology in Spark Ignition Engine

In the present work, computational fluid dynamics approach is adopted to study the possibility of using porous media in combustion and emission in a single-cylinder four-stroke spark ignition engine. The combustion behavior inside the engine without and with application of porous media is studied. The analysis with application of PM signifies enhanced combustion behavior. The compression ratio is kept at 7. Two different types of fluid computational domains are considered, namely, without and with PM. The three-dimensional modeling, meshing and simulations of the combustion chambers are performed with the ANSYS 17.1-FLUENT software. The k–e turbulence model, the premixed combustion model and the spark ignition model are used in the study. The parameters to be analyzed are the variation of cylinder pressure, temperature and turbulence at different crank angles. The results of the computational work without PM are validated with the experimental work, which is executed on the research engine setup operated in SI mode. The work is performed at different engine loads by varying the engine torque, viz. 6 Nm (25%), 12 Nm (50%), 18 Nm (75%) and 24 Nm (100%) along with the no-load condition. The analyses of the results indicate that the peak value of total pressure (1,986,868.99 Pa) and average value of total temperature (632.63 K) with PM at 100% load are lower than without PM (1,992,314.50 Pa and 604.81 K). The concentrations of NOX emissions are significantly reduced by the use of PM for all the loads. The percentage reductions in NOX emissions at no load, 25%, 50%, 75% and 100%, are found to be 2.5%, 11.1%, 9.4%, 9% and 2.12%, respectively.

Analysis and simulation of combustion and emission on small engine

Liquefied Petroleum Gas (LPG) has become an interesting topic in the automotive industry to develop the engines with clean emission characteristics. The usage of gasoline as a fuel to power up the vehicle will contribute to the heavy environmental problem. A single cylinder four-stroke spark ignition (SI) engine that fueled by LPG and gasoline are used to predict and analyze the combustion process in the cylinder. A zero dimensional models are most suitable analytical models for engine cycle simulation. The simulation program has been developed using MATLAB software by implementing a single-zone thermodynamic model. The first law of thermodynamics is applying into this model and Annand’s model was used to compute the convection and radiation of heat transfer within the cylinder. The engine performance parameters computed including the in-cylinder pressure, gas temperature, net heat release, mass fraction burn, brake power, torque, indicated specific fuel consumption. Then, exhaust emission in the cylinder was predicted by the formation of emission model. The results of engine performance are compared between gasoline and LPG as a fuel. Results show LPG engine has contributed to the lower HC and NOx emissions compared to gasoline. It proved that the development of simulation program is useful to calculate the engine performance at different operating points.

The tuning of a small four-stroke spark ignition engine for flexible valve timings through numerical approach

Variable valve timing has been implemented by various manufacturers to improve internal combustion engine performance while operating at wide speed and load ranges. A novel flexible valve timing system for a small four-stroke engine is currently under development by Automotive Engineering Research Group (AERG) in Universiti Malaysia Pahang (UMP). In this paper, a comprehensive intake and exhaust tuning for the flexible variable valve timing is presented. A numerical assessment has been conducted through one dimensional engine modelling and simulation using validated model. There are eight valve timing configurations investigated for the tuning for three main speed regions. The simulation shows a positive and significant impact to the engine performance in three approaches; namely late intake valve closing, early intake valve closing and late exhaust valve closing. These approaches sufficiently covered the whole range of engine speeds for optimum engine operational performance.

Performance and emission analysis of single cylinder SI engine using bioethanol-gasoline blend produced from Salvinia Molesta

Rapid depletion of world’s crude oil reserve, rising global energy demand and concerns about greenhouse gases emission have led to the high-level interest in biofuels. The biofuel, bioethanol is found as an alternative fuel for SI engines as it has similar properties those of gasoline. Higher areal productivity with fast growth rate of microalgae and aquatic weeds makes them promising alternative feedstocks for bioethanol production. In this study, bioethanol produced from S.molesta (aquatic weed) using combined pre-treatment and hydrolysis followed by fermentation with yeast was used to make bioethanol-gasoline blend. The quantity of bioethanol produced from S.molesta was 99.12% pure. The physical properties such as density and heating value of bioethanol were 792.2 kg/m3 and 26.12 MJ/kg, respectively. In this work, the effects of bioethanol-gasoline (E5) fuel blends on the performance and combustion characteristics of a spark ignition (SI) engine were investigated. In the experiments, a single-cylinder, four-stroke SI engine was used. The tests were performed using electric dynamometer while running the engine at the speed (3200 rpm), and seven different load (0, 0.5, 1, 1.5, 2, 2.5 and 3 kW). The results obtained from the use of bioethanol-gasoline fuel blends were compared to those of gasoline fuel. The test results showed an increase of 0.3% in brake thermal efficiency for E5. From the emission analysis, reduced emissions of 39 ppm unburned hydrocarbon, 1.55% carbon monoxide and 2% smoke opacity, respectively was observed with E5 at full load. An increase in CO2 by 0.17% and NOx by 86.7 ppm was observed for E5 at full load.

Prediction of engine performance and emissions with Manihot glaziovii bioethanol − Gasoline blended using extreme learning machine

Bioethanol can potentially replace gasoline because of its lower exhaust emissions. The purpose of this study was to investigate the engine performance and exhaust emissions of Manihot glaziovii bioethanol–gasoline blends at different blend ratios (5%, 10%, 15%, and 20%). Tests were performed on a single-cylinder, four-stroke spark-ignition engine with engine speed was varied from 1600 to 3400rpm, and the properties of the Manihot glaziovii bioethanol–gasoline blends were measured and analysed. The vapour pressure increased for fuel blends with low concentrations of bioethanol due to the oxygen within the bioethanol molecules and the contribution of the flame speed which can enhance the combustion and improved the engine efficiency. In addition, the engine torque, brake power, and brake-specific fuel consumption (BSFC) were measured, as well as the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide emissions. For a fuel blend containing 20% bioethanol at an engine speed of 3200rpm, the BSFC decreased, with maximum values of 270.7g/kWh. The CO and HC emissions were lower for the Manihot glaziovii bioethanol–gasoline blends. In addition, an extreme learning machine (ELM) model was developed for application in the automotive and industrial sectors. This tool reduces the cost, time, and effort associated with experimental data. The blend ratio of the bioethanol–gasoline blends and the engine speed were used as the input data of the model, and the engine performance and exhaust emissions parameters were used as the output data. The coefficient of determination (R2) was within a range of 0.980–1.000, and the mean absolute percentage error was within a range of 0.411%−2.782% for all the parameters. The results indicate that the ELM model is capable of predicting the engine performance and exhaust emissions of bioethanol–gasoline fuel blends.

Quantitative, time-resolved detection of CH<sub>4</sub> concentrations in flows for injection analysis in CNG engines using IR absorption

Abstract. The reduction of CO2 and other greenhouse gas emissions is an important driving force for the development of modern engines. Especially in the transport sector, the use of alternative fuels like methane, the main component of compressed natural gas (CNG), is an applied measure to achieve this goal. This work describes the development of an optical measurement system for accurate quantification of CH4 densities in gas flows based on broadband absorption of infrared light, i.e. non-dispersive IR absorption spectroscopy (NDIR). We demonstrate the capability of the system to achieve high time resolution as well as high measurement accuracy and precision. The optical set-up of the system is designed for usage at the inlet manifold of CNG-fuelled spark ignition engines. It allows for detailed analysis of the mixture formation during single engine cycles. CH4 densities can be determined by monitoring the infrared light attenuation around 3.3 µm caused by the ν3 anti-symmetric C–H-stretch vibration. We calculate the nonlinear relation between transmittance and CH4 density from absorption cross sections calculated from the HITRAN database. The theoretical transmittance signals are corrected for spectral influences of the bandpass filter, the detector sensitivity, the fibre transmittance and the emission spectrum of the light source in order to calculate CH4 densities directly from the measured transmittance. A calibration function corrects remaining differences between experimental and simulated values and improves the accuracy. We show that the sensor system is capable for determination of air–fuel ratios (λ-values) and demonstrate the dynamic quantification of a CH4 injection into a flow channel under various flow conditions. Furthermore, we present the first measurements with a prototype probe capable of measurements inside the inlet manifold of a four-stroke spark ignition engine. We validate the detection strategy in experiments with premixed gases using a modified inlet geometry and demonstrate its application under standard engine operation with port fuel injection while varying the injection parameters.