SI Engine Research Articles

Numerical investigation the effects of the twin-spark plugs coupled with EGR on the combustion process and emissions characteristics in a lean burn natural gas SI engine

Abstract In this study, the single-spark natural gas (NG) SI engine was simulated by using the CFD coupled with detailed combustion mechanism, and validated against with the experiment data. Additionally, the axisymmetrically twin-spark plugs were placed diametrically opposite to each other in the combustion head of the NG SI engine, and fired simultaneously during the simulation cases to trigger two independent spark kernels. The results indicated that twin-spark plugs yielded approximate combustion phasing and better fuel conversion efficiency. Interestingly, in the early stages of flame propagation triggered by the twin-spark plugs configuration, two independent spark kernels looked remarkably similar to the iconic of “Taiji” diagram of the Chinese Taoism, and two independent flame kernels were obviously moved along with the flow. The strong flow pushed the flame front close to the side of the intake port of the NG SI engine equipped with the single-spark plug. While two independent flame fronts of the NG SI engine equipped with the twin-spark plugs were located separately at the intake and exhaust ports in the combustion chamber. Furthermore, two independent flame fronts mutually collided with each other, and generated more independent combustion block areas in the center of the combustion chamber.

Comparative assessment of lube oil, emission and performance of SI engine fueled with two different grades octane numbers

ABSTRACT Energy extraction from fossil fuels is a crucial requirement for the development of any country. Variation in physio-chemical properties of fuels is one of the continuous research areas related to internal combustion engines. Many studies have been performed to ascertain the effect of different gasoline octane numbers on engine performance and emissions without considering lube oil degradation. This study places emphases on the effect of 97-octane (G 97) and 92-octane (G 92) gasoline on lube oil degradation along with emissions and performance in a spark ignition engine. The test engine was run at 80% of wide-open throttle condition to note performance measures like brake power (BP), brake specific fuel consumption (BSFC), and emissions. Subsequently, lube oil samples were collected after engine ran for 120 hours. G 92 revealed improved engine performance in terms of BP (3.1%) and BSFC (6.3%) as compared to G 97. On average, gasoline with higher octane number produced 18.4% higher HC contents than G 92. In addition, lube oil properties and additives diminution (Calcium) depicted a substantial deterioration for G 97. The analyses of lube oil demonstrated 5.8%, 1.1% and 3.6% reduction in average flash point, viscosity and TBN for G 97, respectively. However, wear analysis revealed slightly higher degradation for G 92.

Reducing emissions of an SI engine by alternative spark plugs with hydrogen addition and variable compression ratio

As a consequence of the emissions-cheating scandals and more strict emission regulations enforce researchers to reduce emissions out and find alternative fuels for SI engines. For this purpose, various spark plugs are available in the market with different electrode materials. However, they have not been tested together with different engine parameters. Hence, emissions out from a variable compression spark-ignited engine with different spark plugs and hydrogen enrichment were the scope of this study. The tests were conducted with a four-stroke, single-cylinder, naturally aspirated, variable compression ratio (VCR) engine. Two different compression ratios (CR) of 8.5:1 and 10:1 at maximum brake torque (MBT) spark timing applied to assess the effects of different spark plugs and hydrogen usage at different engine loads. Copper, iridium and platinum spark plugs were tested for each experiment condition. Also, hydrogen was added through the intake manifold with flow rates of 0, 2 and 4 l/min to enhance the combustion of the VCR engine. Carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOx) and unburned hydrocarbons (UHC) emission values were measured in this study. According to test results, with iridium and platinum spark plug usage, hydrogen addition and higher CR, the engine emitted lower CO and UHC at all engine loads. However, a higher amount of CO2 was emitted because of increased completeness of the combustion and the amount of NOx emissions rose due to increment in-cylinder temperatures. These variances were more apparent with platinum spark plug usage compared to the iridium spark plug. As a result, the usage of iridium and platinum spark plugs were shown lower incomplete emissions products out, except NOx emissions.

Assessment of waste bread bioethanol-gasoline blends in respect to combustion analysis, engine performance and exhaust emissions of a SI engine

In this study, bioethanol produced from waste bread by fermentation was evaluated as engine fuel comparing with sugar beet bioethanol purchased. Comparison criteria are parameters of combustion analyses, engine performance and exhaust emissions. Therefore, the experiments were carried out in a single cylinder, four stroke, air cooled SI engine fueled with both bioethanol blended with gasoline in different proportions for different test conditions created with different engine load and a constant engine speed. Whether formed with sugar beet or waste bread bioethanol, fuel blends with similar volumetric contents have similar trends in every sense and their position they take relative to pure gasoline is similar. But when the ones with similar content are compared with each other, the differences emerge. These can be summarized as follows: It has been determined that combustion occurs in a shorter time with lower maximum cylinder pressures and maximum heat release rate if the engine runs with fuels containing waste bread bioethanol. In the case of adding waste bread bioethanol, there was a gradual increase in brake specific fuel consumption and a gradual decrease in thermal efficiency compared to sugar beet added fuels. The use of waste bread bioethanol blended with gasoline has seriously positive results in many emissions aspects such that it has less CO up to 70.9%, less HC up to 34.9% and less NOx up to 5.1%, except for the fact that it has more CO2 up to 3.5%.

SI engine performance, lubricant oil deterioration, and emission: A comparison of liquid and gaseous fuel

Considering the importance of alternative fuels in IC engines for environment safety, compressed natural gas has been extensively employed in SI engines. However, scarce efforts have been made to investigate the effect of compressed natural gas on engine lubricant oil for a long duration. In this regard, a comprehensive analysis has been made on the engine performance, emissions, and lubricant oil conditions using gasoline ( G)92 and compressed natural gas at different operating conditions using reliable sampling methods. The key parameters of the engine performance like brake power and brake-specific energy consumption were investigated at 80% throttle opening within 1500–4500 range of r/min. For the sake of emission tests, speed was varied uniformly by varying the load at a constant throttle. Furthermore, the engine was run at high and low loads for lubricant oil comparison. Although compressed natural gas showed a decrease in brake-specific energy consumption (7.94%) and emissions content, ( G)92 performed relatively better in the case of brake power (39.93% increase). Moreover, a significant improvement was observed for wear debris, lubricant oil physiochemical characteristics, and additives depletion in the case of compressed natural gas than those of ( G)92. The contents of metallic particles were decreased by 23.58%, 36.25%, 42.42%, and 66.67% for iron, aluminum, copper, and lead, respectively, for compressed natural gas.

Optimization of the Efficiency in a Syngas Powered Si Engine Through Numerical Studies Related to the Geometry of the Combustion Chamber

The combustion process occurring in an alternative Spark Ignition (SI) engine powered with bio-syngas from biomass gasification was previously studied by authors through the development of two different numerical models: a 0-1D model developed in the GT-Suite® environment, aimed at gaining a first look upon the main features of the heat release by the syngas and engine performances; a 3D Computational Fluid Dynamics (CFD) model developed within the AVL FireTM software reproducing the engine combustion cycle within a Reynolds Averaged Navier Stokes (RANS) schematization and employing a detailed chemical reaction mechanism to highlight the interaction between the fluid dynamics and the kinetics of the specific biofuel oxidation chain. The numerical results were validated with respect to experimental measurements in a baseline condition, where the presence of a relatively high amount of CO in the exhaust gases was noticed as related to an engine low combustion efficiency, mainly due to the peripheral spark plug position that determines the persistence of residual gases on the opposite side of the combustion chamber wall.The proposed work presents a numerical analysis made through the developed models on the effects of proper changes in the spark plug position. A multi-objective optimization problem is conducted also by varying the Start of Spark (SOS) and the mixture air-to-fuel ratio with the aim of reducing the engine environmental impact without affecting its performances. A centrally mounted spark, along with a correct calibration of the SOS and mixture ratio, allows a reduction of more than 90% of CO emission with respect to the baseline condition without penalizing the engine brake power and efficiency.

Effect of exhaust gas recirculation and hydrogen direct injection on combustion and emission characteristics of a n-butanol SI engine

The n-butanol as a clear and renewable biofuel is considered an ideal alternative fuel for SI engines. Hydrogen as a partial alternative fuel can improve the combustion and emissions of SI engine because of its advantages of low ignition energy, fast flame propagation and so no. In order to decrease the additional NOx caused by hydrogen addition, the cooperative effect of EGR and hydrogen direct injection on combustion and emission in an SI n-butanol engine was investigated in this paper. Experiments are conducted at five hydrogen addition ratios (0%, 5%, 10%, 15%, 20%), five EGR ratios (0%, 5%, 10%, 15%, 20%) and three excess air ratios (1, 1.1, 1.2) with 1500 rpm of engine speed. The results indicate that Ttq, Pmax, dQmax and Tmax decrease with the increasing ηEGR and increase with the increasing φH2, while the APmax, AdQmax, θ0–10 and θ10–90 show the contrary tendency. The 15% EGR rate cooperate with 10%~15% hydrogen addition ratio can keep emissions (HC, CO, NOx) better than the original engine. Compared to the original pure butanol engine, the n-butanol engine with hydrogen direct injection and EGR could obtain better comprehensive performance through the coordinated control of φH2 and ηEGR. More specifically, 15% EGR rate cooperated with 10% hydrogen addition ratio can obtain better comprehensive performance of combustion and emission, but there is a little expense on combustion parameters compared to the original engine under λ = 1. So the 15% EGR ratio is considered a superior EGR ratio cooperated with hydrogen addition.

Joint use of artificial neural networks and particle swarm optimization to determine optimal performance of an ethanol SI engine operating with negative valve overlap strategy

A SI engine fueled with anhydrous ethanol and using NVO was modeled by ANN and hybridization of ANNs with PSO with two standard training methods: Levenberg-Marquardt and Bayesian Regularization. Engine testing results were obtained from a single cylinder Ricardo Hydra camless research engine equipped with a side mounted direct injector. NVO was achieved through early closing of exhaust valves and late opening of intake valves, while engine load was controlled through early intake valve closure. Results showed that both the standard ANN and the ANNs with PSO could accurately predict the outputs, with R2 above 0.93 and mean relative error below 12% for almost all networks. PSO-based ANNs showed an advantage in the prediction of COVIMEP and NOX emissions in case of few neurons in the hidden layer. Input and output mapping of the best ANN showed that SI engine higher indicated efficiencies could be achieved with more advanced spark timings and longer NVO periods in each load block tested. Additionally, it was possible to find an engine part load operating condition around 8.5 bar IMEP where NOX emissions would decrease whereas CO and unburned hydrocarbons emissions would not significantly change, with indicated engine efficiency higher than those found experimentally.

Numerical investigation of water injection quantity and water injection timing on the thermodynamics, combustion and emissions in a hydrogen enriched lean-burn natural gas SI engine

Water direct injection into the cylinder is one of effective ways to suppress the combustion rate and knocking combustion in turbocharged SI engine. In this study, a detailed one-dimensional model coupled with the water direct injection was built by using the GT-Power according to the real tested hydrogen-enriched lean-burn natural gas (NG) SI engine, and validated against the experimental data. Then, a series of cases with various water injection quantity and injection timing were comprehensively investigated on the thermodynamics, combustion and emissions characteristics of the NGSI engine. The impact of the thermo-physical of the water were discussed in detailed by sweeping various water injection quantity and water injection timing. The results indicated that peak combustion pressure and peak heat release rate decreased with the increasing the water injection quantity. In addition, the 50% combustion location and peak combustion pressure location were retarded with the increasing the water injection quantity. As for the water injection timing, the peak combustion pressure and peak combustion temperature were slightly decreased with retarding the water injection timing. Apart from that, the indicated thermal efficiency decreased 4.03% and the equivalent fuel consumption increased 3.56% with injecting 60 mg water into the cylinder compared the case without water injection. Furthermore, the indicated thermal efficiency decreased 4.68% and the equivalent fuel consumption increased 4.66% by sweeping the water injection timing from the 150 CA to 50 CA before top dead center. However, the volumetric efficiency slightly ascended with increasing the water injection quantity and retarding the water injection timing. Finally, the NOx emissions declined with increasing the water injection quantity and retarding the water injection timing. However, CO emission and unburned HC emissions increased with increasing the water injection quantity and retarding the water injection timing. The main aim of this paper is expected to provide a comprehensively assessment of the thermo-physical of water on the thermodynamics, combustion, and emissions of the hydrogen enriched NGSI engine.

An Experimental Investigation on Regulated and Unregulated Emissions of a Gasohol Fueled SI Engine with a Novel Three Way Catalytic Converter

An Experimental Investigation on Regulated and Unregulated Emissions of a Gasohol Fueled SI Engine with a Novel Three Way Catalytic Converter

Near-Wall Flame and Flow Measurements in an Optically Accessible SI Engine

Near-wall processes in internal combustion engines strongly affect heat transfer and pollutant emissions. With continuously improving capabilities to model near-wall processes, the demand for corresponding measurements increases. To obtain an in-depth understanding of the near-wall processes within spark-ignition engines, flame distributions and flow fields were measured simultaneously near the piston surface of an optically accessible engine operating with homogeneous, stoichiometric isooctane–air mixtures. The engine was operated at two engine speeds (800 rpm and 1500 rpm) and two different intake pressures (0.95 bar and 0.4 bar). Flame distributions were obtained at high spatial resolution using high-speed planar laser induced fluorescence of sulfur dioxide (hbox {SO}_{{2}}). Particle tracking velocimetry was utilized to measure the flow field above the piston at high spatial resolution, which enabled the determination of hydrodynamic boundary layer profiles. Flame contours were extracted and statistical distributions of the burnt gas area determined. The burnt gas distributions were compared with the simultaneously recorded high-speed flow field measurements in the unburnt gas. A direct comparison with motored engine operation showed comparable boundary layer profiles until the flame approaches the wall. Flow acceleration due to flame expansion rapidly increases velocity gradients and the boundary layer development becomes highly transient. The interaction of flame and flow depends on the operating conditions, which results in a different evolution of burnt gas positions within the field-of-view. This has additional implications on the development of the velocity boundary layer. Depending on the operating conditions, the flame strongly affects the velocity boundary layer profiles resulting in boundary layer thicknesses (defined by 50% maximum velocity) in the order of 80{-}180, upmu hbox {m}.

Investigating the effect of the air inlet temperature on the combustion characteristics of a spark ignition engine fueled by biogas

AbstractThis work has conducted a numerical study using AVL‐Boost engine simulation utilizing biogas (CH4 and CO2)–air mixtures in a SI engine model. The effect of varying the air manifold temperature from 25 to 50°C on the combustion characteristics as well as engine performance under full load condition in a SI engine fueled by gasoline and biogas mixtures has been investigated. The performed tests involved using variable concentrations of CO2 from 10% to 40% by volume. The current model has been validated with experimental results and it was found that the error in predicting the P‐θ behavior of the engine is about 4.89%. The results showed that, as the air inlet temperature increases, the volumetric efficiency decreases and the brake specific fuel consumption (BSFC) increases for gasoline and all biogas compositions. However, the peak pressure, brake output power, maximum pressure rise rate, and maximum heat release rate were decreased slightly with the increase in air inlet temperature. The effect was only observed for gasoline and the 10%‐CO2 biogas, whereas the effect on the maximum heat release rate was detected on gasoline and biogas compositions up to 20%‐CO2 only. On the other hand, the existence and growth of CO2 content in the biogas reduced significantly the peak pressure, brake output power, maximum pressure rise rate, volumetric efficiency, and both net and maximum heat release rates, though its effect in reducing the volumetric efficiency stopped at 20%‐CO2 biogas. Furthermore, BSFC rises noticeably with the increase in CO2 ratio in biogas. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.

A study on the performance analysis of bioethanol produced from sugarcane molasses in SI engine

Recently with ethanol being a renewable, bio-based and ecofriendly, it is projected to be the best replacement for petrol as a fuel in SI engines. Ethanol is derived mainly from sugarcane, cassava, corn and other waste biomass materials. These materials are rich in calories and could be utilized either as complements or as alternatives for conventional fuel sources. This paper aims to experimentally determine the properties of ethanol/gasoline blends and tests its performances in an SI engine. The E10, E20 and E30 ethanol-gasoline blends were studied and compared to gasoline fuel. It was found that the performance of the engine using bioethanol blends was almost comparable to that of pure gasoline, especially at lower ethanol content blends. Yet, increasing the ethanol content only gives adverse effects to the overall engine performance, resulting in 8.86% power loss at 2000 rpm for E20 and 8.18% for E30 compared to E0. Suggestively, with more research and experiments, bioethanol-fuel blends can replace pure gasoline fuels easily and with many added benefits on the same or slightly modified engines.

Effect of Charge Temperature on Performance of 4s Single Cylinder Twin Spark SI Engine

This study involves the analysis of the performance improvement of the air-cooled SI engine by controlling the charge temperature. The insulated intake manifold has been used to maintaining the charge temperature at the atmospheric temperature level. The effect of variation in intake air temperature coming from atmospheric temperature on the engine performance in terms of brake mean effective pressure, engine power, engine torque are investigated. The result indicated that the mass flow rate of air is increased after using cold and insulated air intake system with average air density of 1.174 kg/m3. This improved air intake mass flow rate increased the brake torque and a reduction in exhaust gas emission. The result shows when the air-fuel mixture allowed for combustion at atmospheric intake air temperature (30ºC), the engine produces 1.2003 kW power and 5.7314 N-m torque at 2000 rpm. The engine performance calculated at an engine speed of 1000, 1500 and 2000 rpm.

Development of the predictive based control of an autonomous engine cooling system for variable engine operating conditions in SI engines: design, modeling and real-time application

This study includes the design of an autonomous cooling system and implementation of the system on gasoline-fueled internal combustion engine by using model predictive control (MPC) technique. The system designed with MPC provides superior performance in terms of engine thermal management compared to the conventional cooling system. This controller structure is selected because it can be easily adaptable to the multivariable control system and is relatively easy to adjust. In the first part of the study, a multi input multi output (MIMO) model for a gasoline engine cooling system is developed under different operating conditions by using system identification techniques. Then, the performance of the proposed predictive based engine cooling system is tested for both steady and transient engine operating conditions. The experimental results showed that the designed autonomous thermal management system outperforms compared to the conventional cooling system in terms of reducing fuel consumption, shortening of the engine warm-up time and improvement of the exhaust emission characteristics.

Optimization of Hole Diameter on Fins of Si Engine through Numeraical Analysis

Fuel and material cost is increasing day by day in all the industries. In IC engine, engine fails mainly due insufficient of heat transfer from the cylinder wall to the atmospheric air. In SI engine, heat is extracted from the cylinder wall by convection heat transfer through the fins. In this paper optimal hole size on the fins is obtained in order to extract the heat from the engine by numerical method. ANSYS is used to find the temperature distribution on the fins , when there no holes, when there is hole diameter as 2mm, 2.5mm,3 mm, 3.5mm,3.8mm, 4mm and two row holes of 3.5 mm diameter. For this analysis fluid flow (fluent) is chosen, air is circulated on engine with 16.666 m/s velocity and with atmospheric pressure. Temperature value of 800K is applied to the cylinder wall. Temperature is compared with the all hole diameter cases, and it is found that the 3.5 mm diameter hole gives the best results compare to all other hole diameter. The temperature difference 0.04K is obtained between without holes and with 3.5 mm diameter. The 3.5 mm diameter hole fins are used where material cost goes at high rate.

Effect of Charge Temperature on Performance of 4s Single Cylinder Twin Spark SI Engine

Effect of Charge Temperature on Performance of 4s Single Cylinder Twin Spark SI Engine

Effect of Octane Number on Performance and Exhaust Emissions of an SI Engine

Spark ignition engines are very popular engines that they are running millions of vehicles all over the world. This engine emits many harmful pollutants, such as CO, UHC, and NOX. In this paper, the impact of gasoline octane number on the engine performance and exhaust emissions was studied. In the tests, four-cylinder, four-stroke engine, and two variable octane numbers (RON83 and 94.5) were used. The engine was run at different engine speeds and loads. The results from the experimental study indicated that the brake specific fuel consumption (bsfc) of RON94.5 was higher than RON83 by 13.93%, while the brake thermal efficiency (ƞbth) was higher for RON83 compared to RON94.5 by 12.31%. The emitted emissions for the tested fuels were high when RON83 was used compared to RON94.5 by 65.52%, 49.11%, and 57.33% for CO, UHC, and NOX, respectively.

Thermal Mapping and Cooling optimization of three-cylinder SI Engine using Computer Aided Engineering

Thermal Mapping and Cooling optimization of three-cylinder SI Engine using Computer Aided Engineering

Evaluation of SI engine performance and emissions using local gasoline fuel and ethanol additive

Evaluation of SI engine performance and emissions using local gasoline fuel and ethanol additive