Skip to main content

Ivan Filipovic

Followers

4

Following

4

Co-authors

3

Public Views

University of Sarajevo

University of Sarajevo

Aleš Hribernik

David Gerhardinger

Faculty of Transport and Traffic Sciences, University of Zagreb

Manuela Žakula

Matija Martinjak

Miroslav Bistrović

Interests

Uploads

Papers by Ivan Filipovic

Utjecaj Fizikalnih Osobina Mješavina Biodizela I Dizela D2 Na Karakteristike Raspršivanja Goriva

Izvorni znanstveni rad / Original scientific paper UTJECAJ FIZIKALNIH OSOBINA MJEŠAVINA BIODIZELA... more Izvorni znanstveni rad / Original scientific paper UTJECAJ FIZIKALNIH OSOBINA MJEŠAVINA BIODIZELA I DIZELA D2 NA KARAKTERISTIKE RASPRŠIVANJA GORIVA Sažetak Uporaba alternativnih goriva u motorima s unutarnjim izgaranjem postaje sve atraktivnija, sa stajališta štednje energije, smanjenja emisije reguliranih zagađivača u ispušnim plinovima te smanjenja emisije CO 2 u okoliš. Kod dizelovih motora, od alternativnih goriva, najviše se radi na uporabi biodizelskog goriva i njegovih mješavina s dizelskim gorivom. Također, nije zanemariva ni uporaba mješavina tekućih i plinovitih goriva (D2 i CNG). Uporaba biodizelskog goriva i njegovih mješavina s dizelskim gorivom u motorima, zbog različitih fizikalnih i kemijskih osobina, ima značajan utjecaj na procese u motoru, od pripreme smjese zrak-gorivo do procesa izgaranja (različito vrijeme pritajenog izgaranja, različita brzina oslobađanja topline, itd.). Za optimalan rad motora, u prvom redu procesa izgaranja, potrebno je poznavati sve utjecajne parametre, koji su posljedica uporabe novog goriva. U ovom radu je napravljena detaljna analiza utjecaja fizikalnih osobina biodizela i njegovih mješavina s dizelskim gorivom, na karakteristike mlaza raspršenog goriva koji ima dominantan utjecaj na proces miješanja goriva i zraka. Rezutati prikazani u ovom radu su kombinacija eksperimentalnih i računskih rezultata, dobivenih pomoću vlastito razvijenog računarskog programa.

Influence of Fuel Properties on Energy Transformation in Fuel Injection System at Diesel Engines

Goriva i maziva : časopis za tribologiju, tehniku podmazivanja i primjenu tekućih i plinovitih goriva i inžinjerstvo izgaranja, Jul 7, 2014

Use of the alternative fuels for propulsion of motor vehicles becomes widespread in all types of ... more Use of the alternative fuels for propulsion of motor vehicles becomes widespread in all types of transport, from public transportation, taxi vehicles up to light duty vehicles intended for use in urban areas. The greatest application of alternative fuels is achieved in case of the minor reconstruction of engine construction (especially in case of diesel engine). However, a special attention should be dedicated to the characteristics of the fuel injection system in case of use of different fuels. The injection characteristics (fuel pressure and velocity at the exit from injector orifice) at diesel engines depend on characteristics of the fuel injection systems and fuel properties. The most important characteristics of the fuel injection system are the following: volumes in the fuel injection system, lengths between locations from fuel pushing to injection, mass of moving parts in the fuel injection system, cross section of fuel flows in the fuel injection system and characteristics of reflection of pressure and velocity waves. In order to improve the injection characteristics, the greatest attention is paid to minimize the volumes of the fuel injection system, especially in the injector. On this way, rapid increasing in pressure gradient (dp/dt), smaller generating reflected pressure waves of fuel and better characteristics were obtained, especially at low load regimes (at small amounts of injected fuel). On the other hand, reducing the volumes in the injection system has the effect of reducing the dimensions (especially the flow channels). This directly affects on the transformation of potential energy (fuel pressure) into kinetic energy (velocity of fuel flow). Any change from potential to kinetic energy in the fuel injection system results an increasing of hydraulic losses and deterioration of the fuel injection characteristics. In the context of the above mentioned facts, the paper presents a detailed analysis of the transformation from potential to kinetic energy of the fuel in the case of the usage of different types of fuel (diesel fuel, biodiesel fuel). A special attention will be dedicated to the injector, where the biggest energy transformation and energy losses in the fuel injection system are occurred.

Novel Approach to Determine Effective Flow Areas at Shock Absorber Restrictions

SAE Technical Paper Series, May 21, 2021

Impact of physical properties of mixture of diesel and biodiesel fuels on hydrodynamic characteristics of fuel injection system

Thermal Science, 2014

One of the alternative fuels, originating from renewable sources, is biodiesel fuel, which is int... more One of the alternative fuels, originating from renewable sources, is biodiesel fuel, which is introduced in diesel engines without major construction modifications on the engine. Biodiesel fuel, by its physical and chemical properties, is different from diesel fuel. Therefore, it is expected that by the application of a biodiesel fuel, the characteristic parameters of the injection system will change. These parameters have a direct impact on the process of fuel dispersion into the engine cylinder, and mixing with the air, which results in an impact on the quality of the combustion process. Method of preparation of the air-fuel mixture and the quality of the combustion process directly affect the efficiency of the engine and the level of pollutant emissions in the exhaust gas, which today is the most important criterion for assessing the quality of the engine. The paper presents a detailed analysis of the influence of physical properties of a mixture of diesel and biodiesel fuels on the output characteristics of the fuel injection system. The following parameters are shown: injection pressure, injection rate, the beginning and duration of injection, transformation of potential into kinetic energy of fuel, and increase of energy losses in fuel injection system of various mixtures of diesel and biodiesel fuels. For the analysis of the results a self-developed computer program was used to simulate the injection process in the system. Computational results are verified using the experiment, for a few mixtures of diesel and biodiesel fuels. This paper presents the verification results for diesel fuel and biodiesel fuel in particular.

Utjecaj Biogoriva Na Performance Dizelovog Motora

Goriva i maziva : časopis za tribologiju, tehniku podmazivanja i primjenu tekućih i plinovitih goriva i inžinjerstvo izgaranja, Dec 21, 2011

Optimization of Injection Law at Modern Diesel Fuel Supply Systems

DS 30: Proceedings of DESIGN 2002, the 7th International Design Conference, Dubrovnik, 2002

Influence of Fuel Properties on Energy Transformation in Fuel Injection System at Diesel Engines

Use of the alternative fuels for propulsion of motor vehicles becomes widespread in all types of ... more Use of the alternative fuels for propulsion of motor vehicles becomes widespread in all types of transport, from public transportation, taxi vehicles up to light duty vehicles intended for use in urban areas. The greatest application of alternative fuels is achieved in case of the minor reconstruction of engine construction (especially in case of diesel engine). However, a special attention should be dedicated to the characteristics of the fuel injection system in case of use of different fuels. The injection characteristics (fuel pressure and velocity at the exit from injector orifice) at diesel engines depend on characteristics of the fuel injection systems and fuel properties. The most important characteristics of the fuel injection system are the following: volumes in the fuel injection system, lengths between locations from fuel pushing to injection, mass of moving parts in the fuel injection system, cross section of fuel flows in the fuel injection system and characteristics o...

Possibilities of Using Dynamic Torsional Vibration Dampers with Springs in Ic Engines for Road Vehicles

Internal combustion engines have a changing value of the current torque at the crankshaft within ... more Internal combustion engines have a changing value of the current torque at the crankshaft within one working cycle (two revolutions of the crankshaft in four-stroke engines for one working cycle) due to their cyclical tape of work and the stochastic nature of the combustion process. Also within the IC engine due specific regulation processes a so called quasi stationary process occurs at constant speed operation [2], which further affects the change of torque at the crankshaft. In addition to the above described character changes of the crankshaft excitation torque, the crank-gear shave variable moments of inertia of rotating masses and the crankshaft has a variable torsional stiffness by cross-sections [2, 3, 5]. All this results in the presence of significant torsional twisting at some cross-sections of the crankshaft with associated elements around the equilibrium of angular rotation. Occurrence of crankshaft twisting at some engine operating modes, primarily due to torsional vib...

Optimization of Injection Law at Modern Diesel Fuel Supply Systems

The most important element that contributes better atomization of air-fuel mixture, as well as be... more The most important element that contributes better atomization of air-fuel mixture, as well as better performing of combustion processes, is an introduction of direct injection of fuel under high pressure into the working chamber of the diesel engine. Beside reduction of pollutants emissions, injection under high pressure makes possible a lower fuel consumption and lower external noise of the diesel engine. A significant attention has been dedicating to design of injection law. A method of calculation of the optimal injection law, as well as an influence of elements of fuel supply systems on the injection law, is presented in the paper.

Effective Reduction of NOx Emissions of Modern Medium Speed Diesel Engines

Good economy and high thermal efficiency of medium-speed diesel engines with direct fuel injectio... more Good economy and high thermal efficiency of medium-speed diesel engines with direct fuel injection are very favourable characteristics in terms of energy conservation and combating global warming. Despite favourable fuel consumption and high efficiency, high emissions of nitrogen oxides (NOX) and particulate matter (PM) are a major problem researchers working on diesel engine development must address. Certainly the biggest challenge today is to make a compromise between optimal nitrogen oxide (NOX) and particulate matter (PM) emissions. Today, nitrogen oxide (NOX) reduction techniques are widely accepted and based on a combination of diluting in-cylinder air charge with a certain amount of exhaust gas, known as exhaust gas recirculation (EGR), and exhaust gas after-treatment using various sophisticated techniques. Results of the influence of the exhaust gas recirculation (EGR) on the emission of nitrogen oxides (NOX), obtained by experimental research on a medium-speed diesel engine are presented in this paper.

Impact of Physical Properties of Diesel and Biodiesel Mixture on Characteristics of Fuel Spraying

The use of alternative fuels in internal combustion engines is becoming increasingly attractive, ... more The use of alternative fuels in internal combustion engines is becoming increasingly attractive, both from the standpoint of energy saving as well as the reduction of emissions of regulated pollutants in the exhaust gases and the reduction of CO2 emissions into the environment. Regarding alternative fuels in diesel engines, most of the work is based on the use of biodiesel and their blends with diesel fuel. Also, the use of a mixture of liquid and gaseous fuels (D2 and CNG) is not negligible. The use of biodiesel and their blends with diesel fuel in the engines, due to variety of physical and chemical properties, has a significant influence on the processes in the engine, from the preparation of the air-fuel mixture to the combustion process (different combustion time, different heat release rate, etc.). For optimum engine performance, but primarily the combustion process, it is necessary to know all influential parameters, which are the result of the use of the new fuel. This paper...

Karakteristika oslobađanja topline kod motora s unutarnjim izgaranjem M-postupkom ubrizgavanja goriva

Electric Karting – from an Idea to the Realisation

Mobility and Vehicle Mechanics, Oct 10, 2018

It is certain that the first steps of the vehicle drives each individual person were made in kart... more It is certain that the first steps of the vehicle drives each individual person were made in karting vehicle. Additional adrenaline and increase driving pleasure gives extremely high noise and the smell of combustion products that may still endure when the ride takes place on an open track during sunny days. However, for many years karting rides take place indoors where it is necessary to provide a special ventilation system for undesirable combustion products. In order to avoid problems of air pollution indoors, reduce noise, and raise awareness of young generations in terms of preservation of the environment, today is increasingly use of electric karting. Having in mind the multiple benefits of electric drive, a reconstruction of karting vehicle with petrol engine into electric karting is presented in the paper. A special attention was paid to the selection of the electric powertrain and battery storage units for electricity, as well as dynamic characteristics of the reconstructed electric vehicle.

A Detailed Model for Simulation of Hydrodynamic Processes in Hydraulic Braking System with ABS on Motor Vehicles

Journal of Scientific Research and Reports, 2016

Aims: Vehicle braking system represents the most important active security system of modern vehic... more Aims: Vehicle braking system represents the most important active security system of modern vehicles. For proper functioning of additional equipment on systems such as ABS, TCS, ESP etc, it is necessary to know the changes in pressure in the entire braking installation. Study Design: The work presents a model for calculating parameters in a braking installation with hydraulic signal transfer. Simulation of hydrodynamic parameters in the brake installation with ABS covered a realistic compressible fluid (braking fluid) and the transfer of signal through the fluid in a form of wave motion. Place and Duration of Study: Faculty of Mechanical Engineering University of Sarajevo, Department for IC Engines and Vehicles leads the researching, while beta runway of International Airport Mostar was used for the measurements. Duration of study: 6 months during 2014 and 2015. Methodology: The method of characteristics is used for calculating hydrodynamic parameters in the pipes of braking installation, and for solving the mass conservation equations, where the compressibility of a fluid is present, the Runge-Kutta forth order method with a variable time step is used. This way it is enabled to define a response of a system for every wheel separately, having in account that the pipes of the braking installation are of different lengths. Results: Numerical results are experimentally proofed, which affirms the use of this method of determining hydraulic parameters in the braking installation and it allows an analysis of realistic conditions of braking of a vehicle under all environmental conditions. Conclusion: A good model for simulation of complete vehicle hydraulic brake system.

Investigation of Dynamics Characteristics of Hybrid Vehicles

The hybrid vehicles become more and more popular on the automotive market. Almost all automobile ... more The hybrid vehicles become more and more popular on the automotive market. Almost all automobile fairs, in recent history, were marked by car manufacturers with presentation of the new hybrid vehicle, even plug-in electrical vehicles. In case of the hybrid vehicles, the combinations of IC Engine and Electromotor can be found in different form of parallel and serial connections. Using one of the mentioned forms, the best use of total energy (power and torque) for vehicle propulsion with lower fuel consumption can be achieved. In order to achieve lower fuel consumption by use of hybrid vehicles in urban areas with limited speeds, only the electromotor is used. However, what can we expect regarding the vehicle dynamics characteristics from these vehicles? The answer to this question is given in this paper with the basic objective to present dynamics characteristics of hybrid vehicles during different driving cycles. In order to investigate the dynamics characteristics of hybrid vehicle...

Influence of Biofuels on Diesel Engine Performance

In principle, emission reduction of toxic substances in exhaust gas of IC diesel engines can be a... more In principle, emission reduction of toxic substances in exhaust gas of IC diesel engines can be achieved at three places: before, in and after the IC engine. The common approach is the introduction of catalytic exhaust systems, valve timing, fuel mixture preparation and combustion modeling, as well as using fuels the chemical composition of which provides the potential for reduction. The latter option seems to be the simplest, but it is not necessarily the first option that would be taken into consideration. Due to the different properties of fuels, it is necessary to optimize individual systems of the internal combustion engine; otherwise, it may happen that the reduction of emissions of toxic substances is absent as a desired effect, or, in the opposite extreme, unacceptable performance of the engine may result. This paper provides an elaboration on the use of bio fuels in the form of rapeseed methyl esters -bio diesel, in terms of performance and the need for optimization of indi...

Impact of physical properties of mixture of diesel and biodiesel fuels on hydrodynamic characteristics of fuel injection system

Thermal Science, 2014

One of the alternative fuels, originating from renewable sources, is biodiesel fuel, which is int... more One of the alternative fuels, originating from renewable sources, is biodiesel fuel, which is introduced in diesel engines without major construction modifications on the engine. Biodiesel fuel, by its physical and chemical properties, is different from diesel fuel. Therefore, it is expected that by the application of a biodiesel fuel, the characteristic parameters of the injection system will change. These parameters have a direct impact on the process of fuel dispersion into the engine cylinder, and mixing with the air, which results in an impact on the quality of the combustion process. Method of preparation of the air-fuel mixture and the quality of the combustion process directly affect the efficiency of the engine and the level of pollutant emissions in the exhaust gas, which today is the most important criterion for assessing the quality of the engine. The paper presents a detailed analysis of the influence of physical properties of a mixture of diesel and biodiesel fuels on ...

Influence of geometric and hydro-dynamic parameters of injector on calculation of spray characteristics of diesel engines

Thermal Science, 2011

The main role in air/fuel mixture formation at the IC diesel engines has the energy introduced by... more The main role in air/fuel mixture formation at the IC diesel engines has the energy introduced by fuel into the IC engine that is the characteristics of spraying fuel into the combustion chamber. The characteristic can be defined by the spray length, the spray cone angle, the physical and the chemical structure of fuel spray by different sections. Having in mind very complex experimental setups for researching in this field, the mentioned characteristics are mostly analyzed by calculations. There are two methods in the literature, the first based on use of the semi-empirical expressions (correlations) and the second, the calculations of spray characteristics by use of very complex mathematical methods. The second method is dominant in the modern literature. The main disadvantage of the calculation methods is a correct definition of real state at the end of the nozzle orifice (real boundary conditions). The majority of the researchers in this field use most frequently the coefficient of total losses inside the injector. This coefficient depends on injector design, as well as depends on the level of fuel energy and fuel energy transformation along the injector. Having in mind the importance of the real boundary conditions, the complex methods for calculation of the fuel spray characteristics should have the calculation of fuel flows inside the injector and the calculation of spray characteristics together. This approach is a very complex numerical problem and there are no existing computer programs with satisfactory calculation results. Analysis of spray characteristics by use of the semi-empirical expressions (correlations) is presented in this paper. The special attention is dedicated to the analysis of the constant in the semi-empirical expressions and influence parameters on this constant. Also, the method for definition of realistic boundary condition at the end of the nozzle orifice is presented in the paper. By use of this method completely avoid a use of the coefficient of total losses inside the injector. At the same time, semi-empirical expressions have the universal constant that does not depend on the injector design.

Heat release characteristic in internal combustion engines with M-type fuel injection procedure

The description of the combustion process in internal combustion engines is typically performed t... more The description of the combustion process in internal combustion engines is typically performed through so-called combustion parameters, such as: the maximum combustion pressure, maximum temperature of the cycle, crankshaft angle of the start of combustion, the angular interval of duration of combustion, the heat release characteristics, thee increment of the total amount of heat developed, the angular interval of combustion delay, the heat transfer etc. Due to the complexity of the combustion process in internal combustion engines to this day there are still no models that could efficiently and above all in a reliable way predict the heat release characteristics for a wide range of different types of IC engines. Phenomenological, empirical and CFD models for specific constructive characters of the engine and fuel applied are targeted explored. The paper presents a procedure for determining the heat release characteristics through approximate functions of combustion, using the examp...

Poboljšanje Ekoloških Performansi Dizelovih Motora Korištenjem Mješavina Konvencionalnih Fosilnih Goriva I Biodizela

Goriva I Maziva, Jun 28, 2013

GOMABN 52, 2, 88-98 Izvorni znanstveni rad / Original scientific paper Autori prof. dr. sc. Dževa... more

Utjecaj Fizikalnih Osobina Mješavina Biodizela I Dizela D2 Na Karakteristike Raspršivanja Goriva

Izvorni znanstveni rad / Original scientific paper UTJECAJ FIZIKALNIH OSOBINA MJEŠAVINA BIODIZELA... more Izvorni znanstveni rad / Original scientific paper UTJECAJ FIZIKALNIH OSOBINA MJEŠAVINA BIODIZELA I DIZELA D2 NA KARAKTERISTIKE RASPRŠIVANJA GORIVA Sažetak Uporaba alternativnih goriva u motorima s unutarnjim izgaranjem postaje sve atraktivnija, sa stajališta štednje energije, smanjenja emisije reguliranih zagađivača u ispušnim plinovima te smanjenja emisije CO 2 u okoliš. Kod dizelovih motora, od alternativnih goriva, najviše se radi na uporabi biodizelskog goriva i njegovih mješavina s dizelskim gorivom. Također, nije zanemariva ni uporaba mješavina tekućih i plinovitih goriva (D2 i CNG). Uporaba biodizelskog goriva i njegovih mješavina s dizelskim gorivom u motorima, zbog različitih fizikalnih i kemijskih osobina, ima značajan utjecaj na procese u motoru, od pripreme smjese zrak-gorivo do procesa izgaranja (različito vrijeme pritajenog izgaranja, različita brzina oslobađanja topline, itd.). Za optimalan rad motora, u prvom redu procesa izgaranja, potrebno je poznavati sve utjecajne parametre, koji su posljedica uporabe novog goriva. U ovom radu je napravljena detaljna analiza utjecaja fizikalnih osobina biodizela i njegovih mješavina s dizelskim gorivom, na karakteristike mlaza raspršenog goriva koji ima dominantan utjecaj na proces miješanja goriva i zraka. Rezutati prikazani u ovom radu su kombinacija eksperimentalnih i računskih rezultata, dobivenih pomoću vlastito razvijenog računarskog programa.

Influence of Fuel Properties on Energy Transformation in Fuel Injection System at Diesel Engines

Goriva i maziva : časopis za tribologiju, tehniku podmazivanja i primjenu tekućih i plinovitih goriva i inžinjerstvo izgaranja, Jul 7, 2014

Use of the alternative fuels for propulsion of motor vehicles becomes widespread in all types of ... more Use of the alternative fuels for propulsion of motor vehicles becomes widespread in all types of transport, from public transportation, taxi vehicles up to light duty vehicles intended for use in urban areas. The greatest application of alternative fuels is achieved in case of the minor reconstruction of engine construction (especially in case of diesel engine). However, a special attention should be dedicated to the characteristics of the fuel injection system in case of use of different fuels. The injection characteristics (fuel pressure and velocity at the exit from injector orifice) at diesel engines depend on characteristics of the fuel injection systems and fuel properties. The most important characteristics of the fuel injection system are the following: volumes in the fuel injection system, lengths between locations from fuel pushing to injection, mass of moving parts in the fuel injection system, cross section of fuel flows in the fuel injection system and characteristics of reflection of pressure and velocity waves. In order to improve the injection characteristics, the greatest attention is paid to minimize the volumes of the fuel injection system, especially in the injector. On this way, rapid increasing in pressure gradient (dp/dt), smaller generating reflected pressure waves of fuel and better characteristics were obtained, especially at low load regimes (at small amounts of injected fuel). On the other hand, reducing the volumes in the injection system has the effect of reducing the dimensions (especially the flow channels). This directly affects on the transformation of potential energy (fuel pressure) into kinetic energy (velocity of fuel flow). Any change from potential to kinetic energy in the fuel injection system results an increasing of hydraulic losses and deterioration of the fuel injection characteristics. In the context of the above mentioned facts, the paper presents a detailed analysis of the transformation from potential to kinetic energy of the fuel in the case of the usage of different types of fuel (diesel fuel, biodiesel fuel). A special attention will be dedicated to the injector, where the biggest energy transformation and energy losses in the fuel injection system are occurred.

Novel Approach to Determine Effective Flow Areas at Shock Absorber Restrictions

SAE Technical Paper Series, May 21, 2021

Impact of physical properties of mixture of diesel and biodiesel fuels on hydrodynamic characteristics of fuel injection system

Thermal Science, 2014

One of the alternative fuels, originating from renewable sources, is biodiesel fuel, which is int... more One of the alternative fuels, originating from renewable sources, is biodiesel fuel, which is introduced in diesel engines without major construction modifications on the engine. Biodiesel fuel, by its physical and chemical properties, is different from diesel fuel. Therefore, it is expected that by the application of a biodiesel fuel, the characteristic parameters of the injection system will change. These parameters have a direct impact on the process of fuel dispersion into the engine cylinder, and mixing with the air, which results in an impact on the quality of the combustion process. Method of preparation of the air-fuel mixture and the quality of the combustion process directly affect the efficiency of the engine and the level of pollutant emissions in the exhaust gas, which today is the most important criterion for assessing the quality of the engine. The paper presents a detailed analysis of the influence of physical properties of a mixture of diesel and biodiesel fuels on the output characteristics of the fuel injection system. The following parameters are shown: injection pressure, injection rate, the beginning and duration of injection, transformation of potential into kinetic energy of fuel, and increase of energy losses in fuel injection system of various mixtures of diesel and biodiesel fuels. For the analysis of the results a self-developed computer program was used to simulate the injection process in the system. Computational results are verified using the experiment, for a few mixtures of diesel and biodiesel fuels. This paper presents the verification results for diesel fuel and biodiesel fuel in particular.

Utjecaj Biogoriva Na Performance Dizelovog Motora

Goriva i maziva : časopis za tribologiju, tehniku podmazivanja i primjenu tekućih i plinovitih goriva i inžinjerstvo izgaranja, Dec 21, 2011

Optimization of Injection Law at Modern Diesel Fuel Supply Systems

DS 30: Proceedings of DESIGN 2002, the 7th International Design Conference, Dubrovnik, 2002

Influence of Fuel Properties on Energy Transformation in Fuel Injection System at Diesel Engines

Use of the alternative fuels for propulsion of motor vehicles becomes widespread in all types of ... more Use of the alternative fuels for propulsion of motor vehicles becomes widespread in all types of transport, from public transportation, taxi vehicles up to light duty vehicles intended for use in urban areas. The greatest application of alternative fuels is achieved in case of the minor reconstruction of engine construction (especially in case of diesel engine). However, a special attention should be dedicated to the characteristics of the fuel injection system in case of use of different fuels. The injection characteristics (fuel pressure and velocity at the exit from injector orifice) at diesel engines depend on characteristics of the fuel injection systems and fuel properties. The most important characteristics of the fuel injection system are the following: volumes in the fuel injection system, lengths between locations from fuel pushing to injection, mass of moving parts in the fuel injection system, cross section of fuel flows in the fuel injection system and characteristics o...

Possibilities of Using Dynamic Torsional Vibration Dampers with Springs in Ic Engines for Road Vehicles

Internal combustion engines have a changing value of the current torque at the crankshaft within ... more Internal combustion engines have a changing value of the current torque at the crankshaft within one working cycle (two revolutions of the crankshaft in four-stroke engines for one working cycle) due to their cyclical tape of work and the stochastic nature of the combustion process. Also within the IC engine due specific regulation processes a so called quasi stationary process occurs at constant speed operation [2], which further affects the change of torque at the crankshaft. In addition to the above described character changes of the crankshaft excitation torque, the crank-gear shave variable moments of inertia of rotating masses and the crankshaft has a variable torsional stiffness by cross-sections [2, 3, 5]. All this results in the presence of significant torsional twisting at some cross-sections of the crankshaft with associated elements around the equilibrium of angular rotation. Occurrence of crankshaft twisting at some engine operating modes, primarily due to torsional vib...

Optimization of Injection Law at Modern Diesel Fuel Supply Systems

The most important element that contributes better atomization of air-fuel mixture, as well as be... more The most important element that contributes better atomization of air-fuel mixture, as well as better performing of combustion processes, is an introduction of direct injection of fuel under high pressure into the working chamber of the diesel engine. Beside reduction of pollutants emissions, injection under high pressure makes possible a lower fuel consumption and lower external noise of the diesel engine. A significant attention has been dedicating to design of injection law. A method of calculation of the optimal injection law, as well as an influence of elements of fuel supply systems on the injection law, is presented in the paper.

Effective Reduction of NOx Emissions of Modern Medium Speed Diesel Engines

Good economy and high thermal efficiency of medium-speed diesel engines with direct fuel injectio... more Good economy and high thermal efficiency of medium-speed diesel engines with direct fuel injection are very favourable characteristics in terms of energy conservation and combating global warming. Despite favourable fuel consumption and high efficiency, high emissions of nitrogen oxides (NOX) and particulate matter (PM) are a major problem researchers working on diesel engine development must address. Certainly the biggest challenge today is to make a compromise between optimal nitrogen oxide (NOX) and particulate matter (PM) emissions. Today, nitrogen oxide (NOX) reduction techniques are widely accepted and based on a combination of diluting in-cylinder air charge with a certain amount of exhaust gas, known as exhaust gas recirculation (EGR), and exhaust gas after-treatment using various sophisticated techniques. Results of the influence of the exhaust gas recirculation (EGR) on the emission of nitrogen oxides (NOX), obtained by experimental research on a medium-speed diesel engine are presented in this paper.

Impact of Physical Properties of Diesel and Biodiesel Mixture on Characteristics of Fuel Spraying

The use of alternative fuels in internal combustion engines is becoming increasingly attractive, ... more The use of alternative fuels in internal combustion engines is becoming increasingly attractive, both from the standpoint of energy saving as well as the reduction of emissions of regulated pollutants in the exhaust gases and the reduction of CO2 emissions into the environment. Regarding alternative fuels in diesel engines, most of the work is based on the use of biodiesel and their blends with diesel fuel. Also, the use of a mixture of liquid and gaseous fuels (D2 and CNG) is not negligible. The use of biodiesel and their blends with diesel fuel in the engines, due to variety of physical and chemical properties, has a significant influence on the processes in the engine, from the preparation of the air-fuel mixture to the combustion process (different combustion time, different heat release rate, etc.). For optimum engine performance, but primarily the combustion process, it is necessary to know all influential parameters, which are the result of the use of the new fuel. This paper...

Karakteristika oslobađanja topline kod motora s unutarnjim izgaranjem M-postupkom ubrizgavanja goriva

Electric Karting – from an Idea to the Realisation

Mobility and Vehicle Mechanics, Oct 10, 2018

It is certain that the first steps of the vehicle drives each individual person were made in kart... more It is certain that the first steps of the vehicle drives each individual person were made in karting vehicle. Additional adrenaline and increase driving pleasure gives extremely high noise and the smell of combustion products that may still endure when the ride takes place on an open track during sunny days. However, for many years karting rides take place indoors where it is necessary to provide a special ventilation system for undesirable combustion products. In order to avoid problems of air pollution indoors, reduce noise, and raise awareness of young generations in terms of preservation of the environment, today is increasingly use of electric karting. Having in mind the multiple benefits of electric drive, a reconstruction of karting vehicle with petrol engine into electric karting is presented in the paper. A special attention was paid to the selection of the electric powertrain and battery storage units for electricity, as well as dynamic characteristics of the reconstructed electric vehicle.

A Detailed Model for Simulation of Hydrodynamic Processes in Hydraulic Braking System with ABS on Motor Vehicles

Journal of Scientific Research and Reports, 2016

Aims: Vehicle braking system represents the most important active security system of modern vehic... more Aims: Vehicle braking system represents the most important active security system of modern vehicles. For proper functioning of additional equipment on systems such as ABS, TCS, ESP etc, it is necessary to know the changes in pressure in the entire braking installation. Study Design: The work presents a model for calculating parameters in a braking installation with hydraulic signal transfer. Simulation of hydrodynamic parameters in the brake installation with ABS covered a realistic compressible fluid (braking fluid) and the transfer of signal through the fluid in a form of wave motion. Place and Duration of Study: Faculty of Mechanical Engineering University of Sarajevo, Department for IC Engines and Vehicles leads the researching, while beta runway of International Airport Mostar was used for the measurements. Duration of study: 6 months during 2014 and 2015. Methodology: The method of characteristics is used for calculating hydrodynamic parameters in the pipes of braking installation, and for solving the mass conservation equations, where the compressibility of a fluid is present, the Runge-Kutta forth order method with a variable time step is used. This way it is enabled to define a response of a system for every wheel separately, having in account that the pipes of the braking installation are of different lengths. Results: Numerical results are experimentally proofed, which affirms the use of this method of determining hydraulic parameters in the braking installation and it allows an analysis of realistic conditions of braking of a vehicle under all environmental conditions. Conclusion: A good model for simulation of complete vehicle hydraulic brake system.

Investigation of Dynamics Characteristics of Hybrid Vehicles

The hybrid vehicles become more and more popular on the automotive market. Almost all automobile ... more The hybrid vehicles become more and more popular on the automotive market. Almost all automobile fairs, in recent history, were marked by car manufacturers with presentation of the new hybrid vehicle, even plug-in electrical vehicles. In case of the hybrid vehicles, the combinations of IC Engine and Electromotor can be found in different form of parallel and serial connections. Using one of the mentioned forms, the best use of total energy (power and torque) for vehicle propulsion with lower fuel consumption can be achieved. In order to achieve lower fuel consumption by use of hybrid vehicles in urban areas with limited speeds, only the electromotor is used. However, what can we expect regarding the vehicle dynamics characteristics from these vehicles? The answer to this question is given in this paper with the basic objective to present dynamics characteristics of hybrid vehicles during different driving cycles. In order to investigate the dynamics characteristics of hybrid vehicle...

Influence of Biofuels on Diesel Engine Performance

In principle, emission reduction of toxic substances in exhaust gas of IC diesel engines can be a... more In principle, emission reduction of toxic substances in exhaust gas of IC diesel engines can be achieved at three places: before, in and after the IC engine. The common approach is the introduction of catalytic exhaust systems, valve timing, fuel mixture preparation and combustion modeling, as well as using fuels the chemical composition of which provides the potential for reduction. The latter option seems to be the simplest, but it is not necessarily the first option that would be taken into consideration. Due to the different properties of fuels, it is necessary to optimize individual systems of the internal combustion engine; otherwise, it may happen that the reduction of emissions of toxic substances is absent as a desired effect, or, in the opposite extreme, unacceptable performance of the engine may result. This paper provides an elaboration on the use of bio fuels in the form of rapeseed methyl esters -bio diesel, in terms of performance and the need for optimization of indi...

Impact of physical properties of mixture of diesel and biodiesel fuels on hydrodynamic characteristics of fuel injection system

Thermal Science, 2014

One of the alternative fuels, originating from renewable sources, is biodiesel fuel, which is int... more One of the alternative fuels, originating from renewable sources, is biodiesel fuel, which is introduced in diesel engines without major construction modifications on the engine. Biodiesel fuel, by its physical and chemical properties, is different from diesel fuel. Therefore, it is expected that by the application of a biodiesel fuel, the characteristic parameters of the injection system will change. These parameters have a direct impact on the process of fuel dispersion into the engine cylinder, and mixing with the air, which results in an impact on the quality of the combustion process. Method of preparation of the air-fuel mixture and the quality of the combustion process directly affect the efficiency of the engine and the level of pollutant emissions in the exhaust gas, which today is the most important criterion for assessing the quality of the engine. The paper presents a detailed analysis of the influence of physical properties of a mixture of diesel and biodiesel fuels on ...

Influence of geometric and hydro-dynamic parameters of injector on calculation of spray characteristics of diesel engines

Thermal Science, 2011

The main role in air/fuel mixture formation at the IC diesel engines has the energy introduced by... more The main role in air/fuel mixture formation at the IC diesel engines has the energy introduced by fuel into the IC engine that is the characteristics of spraying fuel into the combustion chamber. The characteristic can be defined by the spray length, the spray cone angle, the physical and the chemical structure of fuel spray by different sections. Having in mind very complex experimental setups for researching in this field, the mentioned characteristics are mostly analyzed by calculations. There are two methods in the literature, the first based on use of the semi-empirical expressions (correlations) and the second, the calculations of spray characteristics by use of very complex mathematical methods. The second method is dominant in the modern literature. The main disadvantage of the calculation methods is a correct definition of real state at the end of the nozzle orifice (real boundary conditions). The majority of the researchers in this field use most frequently the coefficient of total losses inside the injector. This coefficient depends on injector design, as well as depends on the level of fuel energy and fuel energy transformation along the injector. Having in mind the importance of the real boundary conditions, the complex methods for calculation of the fuel spray characteristics should have the calculation of fuel flows inside the injector and the calculation of spray characteristics together. This approach is a very complex numerical problem and there are no existing computer programs with satisfactory calculation results. Analysis of spray characteristics by use of the semi-empirical expressions (correlations) is presented in this paper. The special attention is dedicated to the analysis of the constant in the semi-empirical expressions and influence parameters on this constant. Also, the method for definition of realistic boundary condition at the end of the nozzle orifice is presented in the paper. By use of this method completely avoid a use of the coefficient of total losses inside the injector. At the same time, semi-empirical expressions have the universal constant that does not depend on the injector design.

Heat release characteristic in internal combustion engines with M-type fuel injection procedure

The description of the combustion process in internal combustion engines is typically performed t... more The description of the combustion process in internal combustion engines is typically performed through so-called combustion parameters, such as: the maximum combustion pressure, maximum temperature of the cycle, crankshaft angle of the start of combustion, the angular interval of duration of combustion, the heat release characteristics, thee increment of the total amount of heat developed, the angular interval of combustion delay, the heat transfer etc. Due to the complexity of the combustion process in internal combustion engines to this day there are still no models that could efficiently and above all in a reliable way predict the heat release characteristics for a wide range of different types of IC engines. Phenomenological, empirical and CFD models for specific constructive characters of the engine and fuel applied are targeted explored. The paper presents a procedure for determining the heat release characteristics through approximate functions of combustion, using the examp...

Poboljšanje Ekoloških Performansi Dizelovih Motora Korištenjem Mješavina Konvencionalnih Fosilnih Goriva I Biodizela

Goriva I Maziva, Jun 28, 2013

GOMABN 52, 2, 88-98 Izvorni znanstveni rad / Original scientific paper Autori prof. dr. sc. Dževa... more