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Combustion stability, engine efficiency and emissions in a multi-cylinder spark-ignition internal combustion engines can be improved through the advanced control and optimization of individual cylinder operation. In this work, experimental and numerical analyses were carried out on a twin-cylinder turbocharged port fuel injection (PFI) spark-ignition engine to evaluate the influence of cylinder-by-cylinder variation on performance and pollutant emissions. In a first stage, experimental tests are performed on the engine at different speed/load points and exhaust gas recirculation (EGR) rates, covering operating conditions typical of Worldwide harmonized Light-duty vehicles Test Cycle (WLTC). Measurements highlighted relevant differences in combustion evolution between cylinders, mainly due to non-uniform effective in-cylinder air/fuel ratio. Experimental data are utilized to validate a one-dimensional (1D) engine model, enhanced with user-defined sub-models of turbulence, combustion, heat transfer and noxious emissions. The model shows a satisfactory accuracy in reproducing the combustion evolution in each cylinder and the temperature of exhaust gases at turbine inlet. The pollutant species (HC, CO and NOx) predicted by the model show a good agreement with the ones measured at engine exhaust. Furthermore, the impact of cylinder-by-cylinder variation on gaseous emissions is also satisfactorily reproduced. The novel contribution of present work mainly consists in the extended numerical/experimental analysis on the effects of cylinder-by-cylinder variation on performance and emissions of spark-ignition engines. The proposed numerical methodology represents a valuable tool to support the engine design and calibration, with the aim to improve both performance and emissions.
Luigi Teodosio; Luca Marchitto; Cinzia Tornatore; Fabio Bozza; Gerardo Valentino. Effect of Cylinder-by-Cylinder Variation on Performance and Gaseous Emissions of a PFI Spark Ignition Engine: Experimental and 1D Numerical Study. Applied Sciences 2021, 11, 6035 .
AMA StyleLuigi Teodosio, Luca Marchitto, Cinzia Tornatore, Fabio Bozza, Gerardo Valentino. Effect of Cylinder-by-Cylinder Variation on Performance and Gaseous Emissions of a PFI Spark Ignition Engine: Experimental and 1D Numerical Study. Applied Sciences. 2021; 11 (13):6035.
Chicago/Turabian StyleLuigi Teodosio; Luca Marchitto; Cinzia Tornatore; Fabio Bozza; Gerardo Valentino. 2021. "Effect of Cylinder-by-Cylinder Variation on Performance and Gaseous Emissions of a PFI Spark Ignition Engine: Experimental and 1D Numerical Study." Applied Sciences 11, no. 13: 6035.
The complexity of modern hybrid powertrains poses new challenges for the optimal control concerning, on one hand, the thermal engine to maximize its efficiency, and, on the other hand, the vehicle to minimize the noxious emissions and CO2. In this context, the engine calibration has to be conducted by considering simultaneously the powertrain management, the vehicle characteristics, and the driving mission. In this work, a calibration methodology for a two-stage boosted ultra-lean pre-chamber spark ignition (SI) engine is proposed, aiming at minimizing its CO2 and pollutant emissions. The engine features a flexible variable valve timing (VVT) control of the valves and an E-compressor, coupled in series to a turbocharger, to guarantee an adequate boost level needed for ultra-lean operation. The engine is simulated in a refined 1D model. A simplified methodology, based on a network of proportional integral derivative (PID) controllers, is presented for the calibration over the whole operating domain. Two calibration variants are proposed and compared, characterized by different fuel and electric consumptions: the first one aims to exclusively maximize the brake thermal efficiency, and the second one additionally considers the electric energy absorbed by the E-compressor and drained from the battery. After a verification against the outcomes of an automatic optimizer, the calibration strategies are assessed based on pollutant and CO2 emissions along representative driving cycles by vehicle simulations. The results highlight slightly lower CO2 emissions with the calibration approach that minimizes the E-compressor consumption, thus revealing the importance of considering the engine calibration phase, the powertrain management, the vehicle characteristics, and its mission.
Fabio Bozza; Vincenzo De Bellis; Enrica Malfi; Luigi Teodosio; Daniela Tufano. Optimal Calibration Strategy of a Hybrid Electric Vehicle Equipped with an Ultra-Lean Pre-Chamber SI Engine for the Minimization of CO2 and Pollutant Emissions. Energies 2020, 13, 4008 .
AMA StyleFabio Bozza, Vincenzo De Bellis, Enrica Malfi, Luigi Teodosio, Daniela Tufano. Optimal Calibration Strategy of a Hybrid Electric Vehicle Equipped with an Ultra-Lean Pre-Chamber SI Engine for the Minimization of CO2 and Pollutant Emissions. Energies. 2020; 13 (15):4008.
Chicago/Turabian StyleFabio Bozza; Vincenzo De Bellis; Enrica Malfi; Luigi Teodosio; Daniela Tufano. 2020. "Optimal Calibration Strategy of a Hybrid Electric Vehicle Equipped with an Ultra-Lean Pre-Chamber SI Engine for the Minimization of CO2 and Pollutant Emissions." Energies 13, no. 15: 4008.
Cooled exhaust gas recirculation (EGR) is a viable technique to mitigate the knock occurrence, to improve the fuel consumption and to reduce the nitrogen oxides (NOx) emissions of spark-ignition engines. This work aims at investigating the effects of a low-pressure cooled EGR system on the performance and exhaust emissions of a small-size turbocharged SI engine through numerical and experimental analyses. First, the experiments are carried out at a speed of 3000 rpm and different engine loads. The standard engine calibration is applied at the reference test conditions. Then, the EGR system is activated and the load is controlled by adjusting the plenum pressure and the spark timing. The experimental results are used to validate a 1D engine model, developed in GT-Power™ software. The latter is integrated with “user-defined” sub-models for an accurate description of the in-cylinder processes, namely turbulence, combustion and heat transfer. Maximum EGR benefits over fuel consumption are achieved at low load, thanks to the reduction of the pumping losses. At high load, minor fuel consumption improvements are obtained, mainly arising from a slight increased knock resistance. Furthermore, increasing EGR rate results in a sensible NOx reduction at each engine load, with a slight penalty on the unburned hydrocarbon emission.
Cinzia Tornatore; Fabio Bozza; Vincenzo De Bellis; Luigi Teodosio; Gerardo Valentino; Luca Marchitto. Experimental and numerical study on the influence of cooled EGR on knock tendency, performance and emissions of a downsized spark-ignition engine. Energy 2019, 172, 968 -976.
AMA StyleCinzia Tornatore, Fabio Bozza, Vincenzo De Bellis, Luigi Teodosio, Gerardo Valentino, Luca Marchitto. Experimental and numerical study on the influence of cooled EGR on knock tendency, performance and emissions of a downsized spark-ignition engine. Energy. 2019; 172 ():968-976.
Chicago/Turabian StyleCinzia Tornatore; Fabio Bozza; Vincenzo De Bellis; Luigi Teodosio; Gerardo Valentino; Luca Marchitto. 2019. "Experimental and numerical study on the influence of cooled EGR on knock tendency, performance and emissions of a downsized spark-ignition engine." Energy 172, no. : 968-976.
Fabio Bozza; Luigi Teodosio; Vincenzo De Bellis; Stefano Fontanesi; Agostino Iorio. A Refined 0D Turbulence Model to Predict Tumble and Turbulence in SI Engines. SAE International Journal of Engines 2018, 12, 15 -30.
AMA StyleFabio Bozza, Luigi Teodosio, Vincenzo De Bellis, Stefano Fontanesi, Agostino Iorio. A Refined 0D Turbulence Model to Predict Tumble and Turbulence in SI Engines. SAE International Journal of Engines. 2018; 12 (1):15-30.
Chicago/Turabian StyleFabio Bozza; Luigi Teodosio; Vincenzo De Bellis; Stefano Fontanesi; Agostino Iorio. 2018. "A Refined 0D Turbulence Model to Predict Tumble and Turbulence in SI Engines." SAE International Journal of Engines 12, no. 1: 15-30.
The modern internal combustion engines show complex architectures in order to improve their performance in terms of brake torque and fuel consumption. Among the different solutions, a compression ratio (CR) increase represents a well assessed path to achieve the above result. However, CR has to be limited in order to comply with the mechanical and thermal engine safety and to avoid knocking combustion. In the present work, a 10-cylinder naturally aspirated spark ignition engine is investigated to evaluate the effects of an increased CR on the performance. In a preliminary stage, the engine is experimentally tested under full load operation for a base CR of 12.6. The main performance parameters and the in-cylinder pressure cycles are measured. The engine is schematized in a one-dimensional model (GT-Power™), where “user routines” are implemented to simulate the turbulence, combustion, knock and heat transfer phenomena. The 1D model is validated against experimental data at full load, denoting a good accuracy. The model is then used to estimate the engine performance variations passing from the base CR up to an increased CR value of 13.3. The results underline a reduced improvement of the engine performance for the higher CR configuration, mainly deriving from a higher thermodynamic efficiency. The proposed methodology shows the capability to predict the effects of a partial engine re-design on a completely theoretical basis and presents the potential to be very helpful in reducing the related experimental costs and time-to-market. Copyright © 2018 Praise Worthy Prize - All rights reserved.
Fabio Bozza; Luigi Teodosio; Vincenzo De Bellis; Diego Cacciatore; Fabrizio Minarelli; Antonio Aliperti. A Modelling Study to Analyse the Compression Ratio Effects on Combustion and Knock Phenomena in a High-Performance Spark-Ignition GDI Engine. International Review on Modelling and Simulations (IREMOS) 2018, 11, 187 .
AMA StyleFabio Bozza, Luigi Teodosio, Vincenzo De Bellis, Diego Cacciatore, Fabrizio Minarelli, Antonio Aliperti. A Modelling Study to Analyse the Compression Ratio Effects on Combustion and Knock Phenomena in a High-Performance Spark-Ignition GDI Engine. International Review on Modelling and Simulations (IREMOS). 2018; 11 (3):187.
Chicago/Turabian StyleFabio Bozza; Luigi Teodosio; Vincenzo De Bellis; Diego Cacciatore; Fabrizio Minarelli; Antonio Aliperti. 2018. "A Modelling Study to Analyse the Compression Ratio Effects on Combustion and Knock Phenomena in a High-Performance Spark-Ignition GDI Engine." International Review on Modelling and Simulations (IREMOS) 11, no. 3: 187.
In this work, various techniques are numerically applied to a base engine - vehicle system to estimate their potential CO2 emission reduction. The reference thermal unit is a downsized turbocharged spark-ignition Variable Valve Actuation (VVA) engine, with a Compression Ratio (CR) of 10. In order to improve its fuel consumption, preserving the original full-load torque, various technologies are considered, including an increased CR, an external low-pressure cooled EGR, and a ported Water Injection (WI).The analyses are carried out by a 1D commercial software (GT-Power™), enhanced by refined user-models for the description of in-cylinder processes, namely turbulence, combustion, heat transfer and knock. The latter were validated with reference to the base engine architecture in previous activities.To minimize the Brake Specific Fuel Consumption (BSFC) all over the engine operating plane, the control parameters of the base and modified engines are calibrated based on PID controllers. The calibration procedure is also verified with a direct fuel consumption minimization carried out by an external optimizer. The calibration provides the optimal Spark Advance (SA), Air-to-Fuel (A/F) ratio, Waste-Gate (WG) opening, and VVA setting, complying with limitations on knock intensity, turbine inlet temperature, boost level, turbocharger speed and in-cylinder pressure peak.The performance and calibration maps are computed for various combinations of the above technologies, including a two-stage CR system, and are compared to the ones related to the base architecture. The results show that EGR offers some BSFC benefits at low load, mainly thanks to the pumping work reduction, while it is practically ineffective for knock mitigation at high load. On the contrary, WI has the potential to substantially increase the knock resistance, improving the fuel consumption at high load. No substantial advantages are, indeed, detected with WI under knock-free operation.Computed BSFC maps are then embedded in a vehicle model with the aim of estimating the CO2 emission of a segment A vehicle over a WLTC. The proposed results give a clear outlook of the above technique potentials and offer a guideline to assess the trade-off between engine complexity and improved CO2 emission.
Fabio Bozza; Vincenzo De Bellis; Luigi Teodosio; Daniela Tufano; Enrica Malfi. Techniques for CO2 Emission Reduction over a WLTC. A Numerical Comparison of Increased Compression Ratio, Cooled EGR and Water Injection. SAE Technical Paper Series 2018, 1 .
AMA StyleFabio Bozza, Vincenzo De Bellis, Luigi Teodosio, Daniela Tufano, Enrica Malfi. Techniques for CO2 Emission Reduction over a WLTC. A Numerical Comparison of Increased Compression Ratio, Cooled EGR and Water Injection. SAE Technical Paper Series. 2018; ():1.
Chicago/Turabian StyleFabio Bozza; Vincenzo De Bellis; Luigi Teodosio; Daniela Tufano; Enrica Malfi. 2018. "Techniques for CO2 Emission Reduction over a WLTC. A Numerical Comparison of Increased Compression Ratio, Cooled EGR and Water Injection." SAE Technical Paper Series , no. : 1.
Recently, a growing interest in the development of more accurate phenomenological turbulence models is observed, since this is a key pre-requisite to properly describe the burn rate in quasi-dimensional combustion models. The latter are increasingly utilized to predict engine performance in very different operating conditions, also including unconventional valve control strategies, such as EIVC or LIVC. Therefore, a reliable phenomenological turbulence model should be able to physically relate the actuated valve strategy to turbulence level during the engine cycle, with particular care in the angular phase when the combustion takes place. Similarly, the capability to sense the effects of engine architecture and intake geometry would improve the turbulence model reliability. 3D-CFD codes are recognized to be able to accurately forecast the evolution of the in-cylinder turbulence field, taking into account both geometrical features (compression ratio, bore-to-stroke ratio, intake runner orientation, valve, piston and head shapes, etc.) and operating conditions (engine speed, boost level, valve strategy). Instead, more common 0D turbulence models usually synthesize geometrical effects in a number of tuning constants and “try” to be sensitive to the operating conditions as much as possible. In this two-part paper, the final goal is the refinement of a previously developed 0D turbulence model, here extended to directly predict the tumble vortex intensity and its close-to-TDC collapse into turbulence. In addition, the model is enhanced to become sensitive to engine geometrical characteristics, such as intake runner orientation, compression ratio, bore-to-stroke ratio and valve number, without requiring any preliminary estimation of the tumble coefficient on a flow bench. Part I describes a background study, where 3D analyses are performed to highlight the effects of operating conditions and main engine geometrical parameters on tumble and turbulence evolution during the engine cycle. In a preliminary stage, the averaging process influence to define representative quantities of mean flow and turbulence is discussed, in order to take into account not-uniformities inside the combustion chamber. 3D simulations are carried out under motored conditions on a VVA engine, at various engine speeds. The VVA device is controlled to simulate both standard, early and late valve closures. The results highlight substantial differences in the mean flow velocity, turbulence intensity and tumble speed among the above cases. To focus the engine geometry impact on the turbulence evolution, further analyses are performed on a different engine, by changing the angle between the intake runners and the cylinder axis. The geometrical compression ratio and the bore-to-stroke ratio are modified, as well. Finally, a two-valve version of this engine is also considered. Results of 3D analyses are discussed to widely assess the effects of valve strategy and main engine geometrical parameters on mean flow, tumble and turbulence evolution inside the combustion chamber. The presented information constitute an extended database for the development and validation of a refined quasi-dimensional model, discussed in the companion part II of the paper.
Fabio Bozza; Vincenzo De Bellis; Fabio Berni; Alessandro D'adamo; Luigi Maresca. Refinement of a 0D Turbulence Model to Predict Tumble and Turbulent Intensity in SI Engines. Part I: 3D Analyses. SAE Technical Paper Series 2018, 1 .
AMA StyleFabio Bozza, Vincenzo De Bellis, Fabio Berni, Alessandro D'adamo, Luigi Maresca. Refinement of a 0D Turbulence Model to Predict Tumble and Turbulent Intensity in SI Engines. Part I: 3D Analyses. SAE Technical Paper Series. 2018; ():1.
Chicago/Turabian StyleFabio Bozza; Vincenzo De Bellis; Fabio Berni; Alessandro D'adamo; Luigi Maresca. 2018. "Refinement of a 0D Turbulence Model to Predict Tumble and Turbulent Intensity in SI Engines. Part I: 3D Analyses." SAE Technical Paper Series , no. : 1.
As known, reliable information about underlying turbulence intensity is a mandatory pre-requisite to predict the burning rate in quasi-dimensional combustion models. Based on 3D results reported in the companion part I paper, a quasi-dimensional turbulence model, embedded under the form of “user routine” in the GT-Power™ software, is here presented in detail. A deep discussion on the model concept is reported, compared to the alternative approaches available in the current literature. The model has the potential to estimate the impact of some geometrical parameters, such as the intake runner orientation, the compression ratio, or the bore-to-stroke ratio, thus opening the possibility to relate the burning rate to the engine architecture.Preliminarily, a well-assessed approach, embedded in GT-Power commercial software v.2016, is utilized to reproduce turbulence characteristics of a VVA engine. This test showed that the model fails to predict tumble intensity for particular valve strategies, such LIVC, thus justifying the need for additional refinements.The model proposed in this work is conceived to solve 3 balance equations, for mean flow kinetic energy, tumble vortex momentum, and turbulent kinetic energy (3-eq. concept). An extended formulation is also proposed, which includes a fourth equation for the dissipation rate, allowing to forecast the integral length scale (4-eq. concept).The impact of the model constants is parametrically analyzed in a first step, and a tuning procedure is advised. Then, a comparison between the 3- and the 4-eq. concepts is performed, highlighting the advantages of the 3-eq. version, in terms of prediction accuracy of turbulence speed-up at the end of the compression stroke. An extensive 3-eq. model validation is then realized according to different valve strategies and engine speeds.The user-model is then utilized to foresee the effects of main geometrical parameters analyzed in part I, namely the intake runner orientation, the compression ratio, and the bore-to-stroke ratio. A two-valve per cylinder engine is also considered. Temporal evolutions of 0D- and 3D-derived mean flow velocity, turbulent intensity, and tumble velocity present very good agreements for each investigated engine geometry and operating condition. The model, particularly, exhibits the capability to accurately predict the tumble trends by varying some geometrical parameter of the engine, which is helpful to estimate the related impact on the burning rate.Summarizing, the developed 0D model well estimates the in-cylinder turbulence characteristics, without requiring any tuning constants adjustment with engine speed and valve strategy. In addition, it demonstrates the capability to properly take into account the intake duct orientation and the compression ratio without tuning adjustments. Some minor tuning variation allows predicting the effects of bore-to-stroke ratio, as well. Finally, the model is verified to furnish good agreements...
Fabio Bozza; Luigi Teodosio; Vincenzo De Bellis; Stefano Fontanesi; Agostino Iorio. Refinement of a 0D Turbulence Model to Predict Tumble and Turbulent Intensity in SI Engines. Part II: Model Concept, Validation and Discussion. SAE Technical Paper Series 2018, 1 .
AMA StyleFabio Bozza, Luigi Teodosio, Vincenzo De Bellis, Stefano Fontanesi, Agostino Iorio. Refinement of a 0D Turbulence Model to Predict Tumble and Turbulent Intensity in SI Engines. Part II: Model Concept, Validation and Discussion. SAE Technical Paper Series. 2018; ():1.
Chicago/Turabian StyleFabio Bozza; Luigi Teodosio; Vincenzo De Bellis; Stefano Fontanesi; Agostino Iorio. 2018. "Refinement of a 0D Turbulence Model to Predict Tumble and Turbulent Intensity in SI Engines. Part II: Model Concept, Validation and Discussion." SAE Technical Paper Series , no. : 1.
In this work, various techniques are numerically investigated in order to assess and quantify their relative effectiveness in reducing the Brake Specific Fuel Consumption (BSFC) of a downsized turbocharged spark-ignition VVA engine. Analyzed solutions include the variable compression ratio, the port Water Injection (WI), and the external cooled EGR.The numerical analysis is developed in a 1D modeling framework. The examined engine is schematized in GT-Power™ environment, employing refined sub-models for an accurate description of in-cylinder processes, such as turbulence, combustion, knock, and heat transfer. In particular, the utilized combustion and knock models have been extensively validated in previous papers, at different speed/load points and intake valve strategies, including operating conditions with a relevant internal EGR rate, and in presence of water injection.The 1D model is coupled to an automatic optimizer, to explore the potential BSFC benefits arising from the adoption of previously listed solutions. The base engine architecture, only including the VVA device, is preliminary optimized to define reference BSFC levels. Then, various solutions are analyzed one by one or combined together, to outline the maximum achievable fuel consumption gains. Operating conditions typical of a WLTP driving cycle are considered.More than proposing an advanced, very complex engine architecture, the aim of the activity is to clearly outline isolated and mutual effects of each technique by varying the operating point. In this way, some guidelines can be offered to engine developers to select the preferred solution, and to have information on the expected improvements.Optimization outcomes show that the WI proves a higher effectiveness at medium-high load, mainly thanks to its knock suppression capability, while cooled EGR is preferable at low load, to reduce the pumping work. If coupled to the WI, adopting a high CR is always beneficial. Combining the above techniques provides BSFC reductions of 6.9%, 5.2% and 9.0% at low, medium and high load, respectively.
Luigi Teodosio; Vincenzo De Bellis; Fabio Bozza. Combined Effects of Valve Strategies, Compression Ratio, Water Injection, and Cooled EGR on the Fuel Consumption of a Small Turbocharged VVA Spark-Ignition Engine. SAE International Journal of Engines 2018, 11, 643 -656.
AMA StyleLuigi Teodosio, Vincenzo De Bellis, Fabio Bozza. Combined Effects of Valve Strategies, Compression Ratio, Water Injection, and Cooled EGR on the Fuel Consumption of a Small Turbocharged VVA Spark-Ignition Engine. SAE International Journal of Engines. 2018; 11 (6):643-656.
Chicago/Turabian StyleLuigi Teodosio; Vincenzo De Bellis; Fabio Bozza. 2018. "Combined Effects of Valve Strategies, Compression Ratio, Water Injection, and Cooled EGR on the Fuel Consumption of a Small Turbocharged VVA Spark-Ignition Engine." SAE International Journal of Engines 11, no. 6: 643-656.
Vincenzo De Bellis; Fabio Bozza; Daniela Tufano. A Comparison Between Two Phenomenological Combustion Models Applied to Different SI Engines. SAE Technical Paper Series 2017, 1 .
AMA StyleVincenzo De Bellis, Fabio Bozza, Daniela Tufano. A Comparison Between Two Phenomenological Combustion Models Applied to Different SI Engines. SAE Technical Paper Series. 2017; ():1.
Chicago/Turabian StyleVincenzo De Bellis; Fabio Bozza; Daniela Tufano. 2017. "A Comparison Between Two Phenomenological Combustion Models Applied to Different SI Engines." SAE Technical Paper Series , no. : 1.
Cinzia Tornatore; Daniela Siano; Luca Marchitto; Arturo Iacobacci; Gerardo Valentino; Fabio Bozza. Water Injection: a Technology to Improve Performance and Emissions of Downsized Turbocharged Spark Ignited Engines. SAE International Journal of Engines 2017, 10, 2319 -2329.
AMA StyleCinzia Tornatore, Daniela Siano, Luca Marchitto, Arturo Iacobacci, Gerardo Valentino, Fabio Bozza. Water Injection: a Technology to Improve Performance and Emissions of Downsized Turbocharged Spark Ignited Engines. SAE International Journal of Engines. 2017; 10 (5):2319-2329.
Chicago/Turabian StyleCinzia Tornatore; Daniela Siano; Luca Marchitto; Arturo Iacobacci; Gerardo Valentino; Fabio Bozza. 2017. "Water Injection: a Technology to Improve Performance and Emissions of Downsized Turbocharged Spark Ignited Engines." SAE International Journal of Engines 10, no. 5: 2319-2329.
Fabio Bozza; Vincenzo De Bellis; Pietro Giannattasio; Luigi Teodosio; Luca Marchitto. Extension and Validation of a 1D Model Applied to the Analysis of a Water Injected Turbocharged Spark Ignited Engine at High Loads and over a WLTP Driving Cycle. SAE International Journal of Engines 2017, 10, 2141 -2153.
AMA StyleFabio Bozza, Vincenzo De Bellis, Pietro Giannattasio, Luigi Teodosio, Luca Marchitto. Extension and Validation of a 1D Model Applied to the Analysis of a Water Injected Turbocharged Spark Ignited Engine at High Loads and over a WLTP Driving Cycle. SAE International Journal of Engines. 2017; 10 (4):2141-2153.
Chicago/Turabian StyleFabio Bozza; Vincenzo De Bellis; Pietro Giannattasio; Luigi Teodosio; Luca Marchitto. 2017. "Extension and Validation of a 1D Model Applied to the Analysis of a Water Injected Turbocharged Spark Ignited Engine at High Loads and over a WLTP Driving Cycle." SAE International Journal of Engines 10, no. 4: 2141-2153.
Luigi Teodosio; Vincenzo De Bellis; Fabio Bozza; Daniela Tufano. Numerical Study of the Potential of a Variable Compression Ratio Concept Applied to a Downsized Turbocharged VVA Spark Ignition Engine. SAE Technical Paper Series 2017, 1 .
AMA StyleLuigi Teodosio, Vincenzo De Bellis, Fabio Bozza, Daniela Tufano. Numerical Study of the Potential of a Variable Compression Ratio Concept Applied to a Downsized Turbocharged VVA Spark Ignition Engine. SAE Technical Paper Series. 2017; ():1.
Chicago/Turabian StyleLuigi Teodosio; Vincenzo De Bellis; Fabio Bozza; Daniela Tufano. 2017. "Numerical Study of the Potential of a Variable Compression Ratio Concept Applied to a Downsized Turbocharged VVA Spark Ignition Engine." SAE Technical Paper Series , no. : 1.
Vincenzo De Bellis; Fabio Bozza; Luigi Teodosio; Gerardo Valentino. Experimental and Numerical Study of the Water Injection to Improve the Fuel Economy of a Small Size Turbocharged SI Engine. SAE International Journal of Engines 2017, 10, 550 -561.
AMA StyleVincenzo De Bellis, Fabio Bozza, Luigi Teodosio, Gerardo Valentino. Experimental and Numerical Study of the Water Injection to Improve the Fuel Economy of a Small Size Turbocharged SI Engine. SAE International Journal of Engines. 2017; 10 (2):550-561.
Chicago/Turabian StyleVincenzo De Bellis; Fabio Bozza; Luigi Teodosio; Gerardo Valentino. 2017. "Experimental and Numerical Study of the Water Injection to Improve the Fuel Economy of a Small Size Turbocharged SI Engine." SAE International Journal of Engines 10, no. 2: 550-561.
Referring to spark-ignition engines, the downsizing, coupled to turbocharging and variable valve actuation systems are very common solutions to reduce the brake-specific fuel consumption at low-medium brake mean effective pressure. However, the adoption of such solutions increases the complexity of engine control and management because of the additional degrees of freedom, and hence results in a longer calibration time and higher experimental efforts. In this work, a twin-cylinder turbocharged variable valve actuation spark-ignition engine is numerically investigated by a one-dimensional model (GT-Power™). The considered engine is equipped with a fully flexible variable valve actuation system, realizing both a common full-lift strategy and a more advanced early intake valve closure strategy. Refined sub-models are used to describe turbulence and combustion processes. In the first stage, one-dimensional engine model is validated against the experimental data at full and part load. The validated model is then integrated in a multipurpose commercial optimizer (modeFRONTIER™) with the aim to identify the engine calibration that minimizes brake-specific fuel consumption at part load. In particular, the decision parameters of the optimization process are the early intake valve closure angle, the throttle valve opening, the turbocharger setting and the spark timing. Proper constraints are posed for intake pressure in order to limit the gas-dynamic noise radiated at the intake mouth. The adopted optimization approach shows the capability to reproduce with good accuracy the experimentally identified calibration. The latter corresponds to the numerically derived Pareto frontier in brake mean effective pressure–brake specific fuel consumption plane. The optimization also underlines the advantages of an engine calibration based on a combination of early intake valve closure strategy and intake throttling rather than a purely throttle-based calibration. The developed automatic procedure allows for a ‘virtual’ calibration of the considered engine on completely theoretical basis and proves to be very helpful in reducing the experimental costs and the engine time-to-market.
Fabio Bozza; Vincenzo De Bellis; Luigi Teodosio. A numerical procedure for the calibration of a turbocharged spark-ignition variable valve actuation engine at part load. International Journal of Engine Research 2016, 18, 810 -823.
AMA StyleFabio Bozza, Vincenzo De Bellis, Luigi Teodosio. A numerical procedure for the calibration of a turbocharged spark-ignition variable valve actuation engine at part load. International Journal of Engine Research. 2016; 18 (8):810-823.
Chicago/Turabian StyleFabio Bozza; Vincenzo De Bellis; Luigi Teodosio. 2016. "A numerical procedure for the calibration of a turbocharged spark-ignition variable valve actuation engine at part load." International Journal of Engine Research 18, no. 8: 810-823.
Daniela Siano; Gerardo Valentino; Fabio Bozza; Arturo Iacobacci; Luca Marchitto. A Non-Linear Regression Technique to Estimate from Vibrational Engine Data the Instantaneous In-Cylinder Pressure Peak and Related Angular Position. SAE Technical Paper Series 2016, 1 .
AMA StyleDaniela Siano, Gerardo Valentino, Fabio Bozza, Arturo Iacobacci, Luca Marchitto. A Non-Linear Regression Technique to Estimate from Vibrational Engine Data the Instantaneous In-Cylinder Pressure Peak and Related Angular Position. SAE Technical Paper Series. 2016; ():1.
Chicago/Turabian StyleDaniela Siano; Gerardo Valentino; Fabio Bozza; Arturo Iacobacci; Luca Marchitto. 2016. "A Non-Linear Regression Technique to Estimate from Vibrational Engine Data the Instantaneous In-Cylinder Pressure Peak and Related Angular Position." SAE Technical Paper Series , no. : 1.
Vincenzo De Bellis; Fabio Bozza; Daniela Siano; Gerardo Valentino. A Modeling Study of Cyclic Dispersion Impact on Fuel Economy for a Small Size Turbocharged SI Engine. SAE International Journal of Engines 2016, 9, 2066 -2078.
AMA StyleVincenzo De Bellis, Fabio Bozza, Daniela Siano, Gerardo Valentino. A Modeling Study of Cyclic Dispersion Impact on Fuel Economy for a Small Size Turbocharged SI Engine. SAE International Journal of Engines. 2016; 9 (4):2066-2078.
Chicago/Turabian StyleVincenzo De Bellis; Fabio Bozza; Daniela Siano; Gerardo Valentino. 2016. "A Modeling Study of Cyclic Dispersion Impact on Fuel Economy for a Small Size Turbocharged SI Engine." SAE International Journal of Engines 9, no. 4: 2066-2078.
Daniela Siano; Fabio Bozza. Improving Acoustic Performance of an Air Filter Box. TL Analysis and Device Optimization. SAE Technical Paper Series 2016, 1 .
AMA StyleDaniela Siano, Fabio Bozza. Improving Acoustic Performance of an Air Filter Box. TL Analysis and Device Optimization. SAE Technical Paper Series. 2016; ():1.
Chicago/Turabian StyleDaniela Siano; Fabio Bozza. 2016. "Improving Acoustic Performance of an Air Filter Box. TL Analysis and Device Optimization." SAE Technical Paper Series , no. : 1.
Fabio Bozza; Vincenzo De Bellis; Luigi Teodosio. Potentials of cooled EGR and water injection for knock resistance and fuel consumption improvements of gasoline engines. Applied Energy 2016, 169, 112 -125.
AMA StyleFabio Bozza, Vincenzo De Bellis, Luigi Teodosio. Potentials of cooled EGR and water injection for knock resistance and fuel consumption improvements of gasoline engines. Applied Energy. 2016; 169 ():112-125.
Chicago/Turabian StyleFabio Bozza; Vincenzo De Bellis; Luigi Teodosio. 2016. "Potentials of cooled EGR and water injection for knock resistance and fuel consumption improvements of gasoline engines." Applied Energy 169, no. : 112-125.
It is widely recognized that spatial and temporal evolution of both macro-and micro-turbulent scales inside internal combustion engines affect air-fuel mixing, combustion and pollutants formation. Particularly, in spark ignition engines, tumbling macro-structure induces the generation of a proper turbulence level to sustain the development and propagation of the flame front. As known, 3D-CFD codes are able to describe the evolution of the in-cylinder flow and turbulence fields with good accuracy, although a high computational effort is required. For this reason, only a limited set of operating conditions is usually investigated. On the other hand, thanks to a lower computational burden, 1D codes can be employed to study engine performance in the whole operating domain, despite of a less detailed description of in-cylinder processes. The integration of 1D and 3D approaches appears hence a promising path to combine the advantages of both. In the present paper, a 0D phenomenological mean flow and turbulence model belonging to the K-k model family is presented in detail. The latter is implemented in the GT-Power™ software under the form of “user routine”. The model is tuned against in-cylinder results provided by 3D-CFD analyses carried out by the Star-CD™ code at two engine speeds under motored operation. In particular, a currently produced twin-cylinder turbocharged VVA engine is analyzed. The 0D model is then validated against further 3D results at various engine speeds and intake valve lifts, including early closure strategies, both under motored and fired operation. The proposed 0D mean flow and turbulence model shows the capability to accurately estimate the temporal evolution of the incylinder turbulence for all the considered operating conditions, without requiring any case-dependent tuning, proving its generality and reliability
Vincenzo De Bellis; Fabio Bozza; Stefano Fontanesi; Elena Severi; Fabio Berni. Development of a Phenomenological Turbulence Model through a Hierarchical 1D/3D Approach Applied to a VVA Turbocharged Engine. SAE International Journal of Engines 2016, 9, 506 -519.
AMA StyleVincenzo De Bellis, Fabio Bozza, Stefano Fontanesi, Elena Severi, Fabio Berni. Development of a Phenomenological Turbulence Model through a Hierarchical 1D/3D Approach Applied to a VVA Turbocharged Engine. SAE International Journal of Engines. 2016; 9 (1):506-519.
Chicago/Turabian StyleVincenzo De Bellis; Fabio Bozza; Stefano Fontanesi; Elena Severi; Fabio Berni. 2016. "Development of a Phenomenological Turbulence Model through a Hierarchical 1D/3D Approach Applied to a VVA Turbocharged Engine." SAE International Journal of Engines 9, no. 1: 506-519.