Muammer Özkan - Academia.edu (original) (raw)

Papers by Muammer Özkan

Research paper thumbnail of The Impact of Bus Heating Ventilation and Air Conditioning Systems on Real-World Energy Consumption and Co2 Emissions

Research paper thumbnail of The Use of VECTO for the Evaluation and Optimization of Public Transport CO2 Emissions

Research paper thumbnail of Optimization Of Fuel Consumption Of A Bus Used In City Line With Regulation Of Driving Characteristics

The fuel cost of the motor vehicle operating on its common route is an important part of the oper... more The fuel cost of the motor vehicle operating on its common route is an important part of the operating cost. Therefore, the importance of the fuel saving is increasing day by day. One of the parameters which improve fuel saving is the regulation of driving characteristics. The number and duration of stop is increased by the heavy traffic load. It is possible to improve the fuel saving with regulation of traffic flow and driving characteristics. The researches show that the regulation of the traffic flow decreases fuel consumption, but it is not enough to improve fuel saving without the regulation of driving characteristics. This study analyses the fuel consumption of two trips of city bus operating on its common route and determines the effect of traffic density and driving characteristics on fuel consumption. Finally it offers some suggestions about regulation of driving characteristics to improve the fuel saving. Fuel saving is determined according to the results obtained from sim...

Research paper thumbnail of Artificial Neural Network Approach to Predicting en Gine-Out Emissions and Performance Parameters of a Turbo Cha Rged Diesel

This study details the artificial neural network (A NN) modelling of a diesel engine to predict t... more This study details the artificial neural network (A NN) modelling of a diesel engine to predict the torque, power, brake-specific fuel consumption and pollutant emissions, including carbon dioxide, carb on monoxide, nitrogen oxides, total hydrocarbons and filter smoke number. To collect data for training and testing the neural network, experiment s were performed on a four cylinder, four stroke compression ignition eng ine. A total of 108 test points were run on a dynamometer. For the first par t of this work, a parameter packet was used as the inputs for the neu ral network, and satisfactory regression was found with the outputs (over ~95%), excluding total hydrocarbons. The second stage of this work a ddressed developing new networks with additional inputs for predicting the total hydrocarbons, and the regression was raised from 75 % to 90 %. This s tudy shows that the ANN approach can be used for accurately predicting char acteristic values of an internal combustion engine and th...

Research paper thumbnail of CO2 Analyses with Model-Based Regulatory Tools: Vecto Application for Istanbul Public Transportation Case

International Journal of Energy for a Clean Environment, 2022

Research paper thumbnail of Evaluation of pollutant emissions generated at bus stops

Research paper thumbnail of Numerical Investigation and Multi-Objective Optimization of Internal EGR and Post-Injection Strategies on the Combustion, Emission and Performance of a Single Cylinder, Heavy-Duty Diesel Engine

Energies, 2020

This work presents a numerical study that investigates the optimum post-injection strategy and in... more This work presents a numerical study that investigates the optimum post-injection strategy and internal exhaust gas recirculation (iEGR) application with intake valve re-opening (2IVO) aiming to optimize the brake specific nitric oxide (bsNO) and brake specific soot (bsSoot) trade-off with reasonable brake specific fuel consumption (BSFC) via 1D engine cycle simulation. For model validation, single and post-injection test results obtained from a heavy-duty single cylinder diesel research engine were used. Then, the model was modified for 2IVO application. Following the simulations performed based on Latin hypercube DoE; BSFC, bsNO and bsSoot response surfaces trained by feedforward neural network were generated as a function of the injection (start of main injection, post-injection quantity, post-injection dwell time) and iEGR (2IVO dwell) parameters. After examining the effect of each parameter on pollutant emission and engine performance, multi-objective pareto optimization was pe...

Research paper thumbnail of Fuel consumption and emission evaluation of a rapid bus transport system at different operating conditions

Fuel, 2020

The real driving emissions of vehicles have attracted great interest in recent years due to the i... more The real driving emissions of vehicles have attracted great interest in recent years due to the increased environmental awareness. Public transport systems using internal combustion engines contributes greenhouse gases and harmful pollutants significantly. The routes of public transport mainly include urban areas with high population density. From this perspective, analyzing of the public transport systems real driving emissions is important for creating environmentally friendly cities. The economy of fossil fueled public transportation is another major concern that should be optimized. There are few studies focusing on the emission characteristics of public transport buses currently working on dedicated routes. In this context one of the biggest transport axle of the world, Metrobus Rapid Bus Transport system is analyzed. The Metrobus equipped with portable emission measurement systems and portable fuel consumption meter is used for measurement activities. Then the results are analyzed in terms of emissions and fuel consumption regarding to the operating parameters. The results showed that the driving behavior has great effect on both emissions and fuel consumption. It was shown that the accumulated emissions near bus stop can strongly affect the public health. The emissions and fuel consumption are both analyzed regarding to the acceleration and speed. The emissions and fuel factors are developed and compared with the values indicated in the literature. It was also analyzed that it is possible to lower emissions with operating the vehicle some certain regions.

Research paper thumbnail of Simulating City-Bus On-Road Operation With VECTO

Frontiers in Mechanical Engineering, 2019

Heavy-duty vehicles constitute a significant contributor to road CO 2 emissions, despite accounti... more Heavy-duty vehicles constitute a significant contributor to road CO 2 emissions, despite accounting for only a low share of the vehicle fleet. CO 2 Emissions certification and monitoring are performed using vehicle simulation software designed for the purpose (VECTO). The European Union currently regulates rigid truck and tractor-trailer CO 2 emissions and subsequently will proceed to buses and other heavy-duty vehicle categories. The current study investigated the use of VECTO on a city bus by modeling the on-road operating conditions of a vehicle in an urban route in Istanbul. The simulation results for constant auxiliary load showed a difference with the on-road measurements in the range of −1.6 to 3.2%, depending on the direction of the route. The difference was attributed to the influence of the total elevation change, and the use of auxiliaries. The latter comprise a significant part of energy consumption in buses, and for this reason, VECTO includes a dedicated bus auxiliary module. The use of the module was also explored, and it was found to improve the results in some cases. The findings highlight the need to assess the operation of auxiliary components in city buses accurately, and to consider the provision of more precise, auxiliary-component specific, information when running actual real-world CO 2 simulations of these vehicles.

Research paper thumbnail of A fuel consumption model for public transportation with 3-D road geometry approach

Thermal Science, 2018

Public transportation fuel consumption modeling shows a great importance because of economic and ... more Public transportation fuel consumption modeling shows a great importance because of economic and environmental aspects. Considering to the metropolises with millions of inhabitants with circulating thousands of buses that uses intercity lines, its importance is becoming vital in planning both operation of transportation company and city mobility planning. In this context a detailed fuel consumption modelling approach for public transportation buses was used for vehicle fuel consumption assessment during operation. The methodology was developed with IPG TruckMaker + AVL Cruise co-simulation environment following instantaneous speed, load and 3-D road data primarily besides model parameters. The model was validated at one of the most important public transportation axle of the world, Istanbul Metrobus System, at two direction which carries over ~1 million passenger daily in 24 hours operation with petrol engine buses. The comparison simulation/measurements showed that the proposed fuel consumption model is accurate and can predict fuel consumption behavior for public transit buses in a reliable band. In addition, this methodology can be used to investigate various powertrain and operating scenarios near future for more efficient public transportation with high reliability.

Research paper thumbnail of Assesment of real driving emissions of a bus operating on a dedicated route

Thermal Science, 2018

The reducing of real driving emissions from public transportation which is using intracity lines ... more The reducing of real driving emissions from public transportation which is using intracity lines has become more important in recent years. This is because the petroleum derived fuel combustion products contributes the global warming as well as adversely the air quality. The fuel consumption perspective is another major economical concern for operating companies that should be optimized. In this context a part of Istanbul Metrobus public transportation system of which is using fully a dedicated line is assessed via on board emission and fuel metering devices for two loading conditions. The relevant vehicle and engine operating data is logged during the tests. The logged data is post processed for developing the average emission factors. The results are also analyzed from acceleration and altitude change perspective and alternative scenarios are discussed for cleaner and economic operation. Lastly the in-service conformity parameters are identified and the results are compared with h...

Research paper thumbnail of Istanbul Metrobus Line Fuel Consumption Optimization via 3D Road Model by Using Avl Cruise Ipg Truck Maker Co-Simulation

INTERNATIONAL JOURNAL OF ADVANCES ON AUTOMOTIVE AND TECHNOLOGY, 2017

Research paper thumbnail of Modelling analysis of multiple diesel injection strategies with one-dimensional simulation coupled with artificial neural networks

Thermal Science, 2017

In the modern Diesel injection systems the phasing of injection in the same cycle gives a high fl... more In the modern Diesel injection systems the phasing of injection in the same cycle gives a high flexibility to engineers from the perspective of engines performance and emission optimization. Basically, the injection is separated in to three phases: the pilot, main, and post injection phases. The focus of this study is based on pilot injection strategy implementation, which can be used for emission control effectively. In this work, reference main and pilot + main injection strategy experiments were realized in a modern Diesel engine. The logged data groups were used to model the engine at 1-D thermodynamic simulation AVL BOOST. In the second stage of this work, the engine operating points which are not realized at test bench are made run at BOOST programme. The new model parameters of simulation are identified with artificial neural network technique. The results showed that the implementation of appropriate mass of pilot injection at the appropriate injection advance will reduce th...

Research paper thumbnail of Effects of soybean biodiesel on a DI diesel engine performance, emission and combustion characteristics

Fuel, 2014

h i g h l i g h t s " Soybean biodiesel and B10, B20, B50 blends were tested with a single cylind... more h i g h l i g h t s " Soybean biodiesel and B10, B20, B50 blends were tested with a single cylinder diesel engine. " Biodiesel showed significant decreases at CO and THC emissions while NO x increased. " Biodiesel usage shortened the ignition delay. " Biodiesel could be used without any modification on diesel engine.

Research paper thumbnail of Experimental study on energy and exergy analyses of a diesel engine performed with multiple injection strategies: Effect of pre-injection timing

Applied Thermal Engineering, 2013

Several studies in the literature treat the effects of ambient conditions and alternative fuel us... more Several studies in the literature treat the effects of ambient conditions and alternative fuel usage on the thermal and exergetic efficiencies of diesel engines. Different from other studies this study investigates the influence of the dwell time of multiple injection events on the thermal and exergetic efficiencies. A test engine was run using three different injection strategies. The main injection timing, the total fuel injected into the combustion chamber per cycle, the engine speed, the rail pressure and the intake manifold pressure were held constant, and the pre-injection timing was varied during the engine tests. Using the results of the engine experiments, the heat release rate, combustion temperature, heat balance, thermal efficiency, and exergetic efficiency were calculated. While it wasn't obtained any significant change in the thermal efficiency, exergetic efficiency and the exergy, the NOx emissions decreased by 7.4% via implementing appropriate pre-injection mass and injection advance. The combustion temperature and cooling heat loss decreased, while the exhaust heat loss increased when using the pre-injection strategies. The results demonstrate that pre-injection strategies, whose main goal is reducing NOx emissions, cause negligible losses in the thermal and exergetic efficiencies.

Research paper thumbnail of The Impact of Bus Heating Ventilation and Air Conditioning Systems on Real-World Energy Consumption and Co2 Emissions

Research paper thumbnail of The Use of VECTO for the Evaluation and Optimization of Public Transport CO2 Emissions

Research paper thumbnail of Optimization Of Fuel Consumption Of A Bus Used In City Line With Regulation Of Driving Characteristics

The fuel cost of the motor vehicle operating on its common route is an important part of the oper... more The fuel cost of the motor vehicle operating on its common route is an important part of the operating cost. Therefore, the importance of the fuel saving is increasing day by day. One of the parameters which improve fuel saving is the regulation of driving characteristics. The number and duration of stop is increased by the heavy traffic load. It is possible to improve the fuel saving with regulation of traffic flow and driving characteristics. The researches show that the regulation of the traffic flow decreases fuel consumption, but it is not enough to improve fuel saving without the regulation of driving characteristics. This study analyses the fuel consumption of two trips of city bus operating on its common route and determines the effect of traffic density and driving characteristics on fuel consumption. Finally it offers some suggestions about regulation of driving characteristics to improve the fuel saving. Fuel saving is determined according to the results obtained from sim...

Research paper thumbnail of Artificial Neural Network Approach to Predicting en Gine-Out Emissions and Performance Parameters of a Turbo Cha Rged Diesel

This study details the artificial neural network (A NN) modelling of a diesel engine to predict t... more This study details the artificial neural network (A NN) modelling of a diesel engine to predict the torque, power, brake-specific fuel consumption and pollutant emissions, including carbon dioxide, carb on monoxide, nitrogen oxides, total hydrocarbons and filter smoke number. To collect data for training and testing the neural network, experiment s were performed on a four cylinder, four stroke compression ignition eng ine. A total of 108 test points were run on a dynamometer. For the first par t of this work, a parameter packet was used as the inputs for the neu ral network, and satisfactory regression was found with the outputs (over ~95%), excluding total hydrocarbons. The second stage of this work a ddressed developing new networks with additional inputs for predicting the total hydrocarbons, and the regression was raised from 75 % to 90 %. This s tudy shows that the ANN approach can be used for accurately predicting char acteristic values of an internal combustion engine and th...

Research paper thumbnail of CO2 Analyses with Model-Based Regulatory Tools: Vecto Application for Istanbul Public Transportation Case

International Journal of Energy for a Clean Environment, 2022

Research paper thumbnail of Evaluation of pollutant emissions generated at bus stops

Research paper thumbnail of Numerical Investigation and Multi-Objective Optimization of Internal EGR and Post-Injection Strategies on the Combustion, Emission and Performance of a Single Cylinder, Heavy-Duty Diesel Engine

Energies, 2020

This work presents a numerical study that investigates the optimum post-injection strategy and in... more This work presents a numerical study that investigates the optimum post-injection strategy and internal exhaust gas recirculation (iEGR) application with intake valve re-opening (2IVO) aiming to optimize the brake specific nitric oxide (bsNO) and brake specific soot (bsSoot) trade-off with reasonable brake specific fuel consumption (BSFC) via 1D engine cycle simulation. For model validation, single and post-injection test results obtained from a heavy-duty single cylinder diesel research engine were used. Then, the model was modified for 2IVO application. Following the simulations performed based on Latin hypercube DoE; BSFC, bsNO and bsSoot response surfaces trained by feedforward neural network were generated as a function of the injection (start of main injection, post-injection quantity, post-injection dwell time) and iEGR (2IVO dwell) parameters. After examining the effect of each parameter on pollutant emission and engine performance, multi-objective pareto optimization was pe...

Research paper thumbnail of Fuel consumption and emission evaluation of a rapid bus transport system at different operating conditions

Fuel, 2020

The real driving emissions of vehicles have attracted great interest in recent years due to the i... more The real driving emissions of vehicles have attracted great interest in recent years due to the increased environmental awareness. Public transport systems using internal combustion engines contributes greenhouse gases and harmful pollutants significantly. The routes of public transport mainly include urban areas with high population density. From this perspective, analyzing of the public transport systems real driving emissions is important for creating environmentally friendly cities. The economy of fossil fueled public transportation is another major concern that should be optimized. There are few studies focusing on the emission characteristics of public transport buses currently working on dedicated routes. In this context one of the biggest transport axle of the world, Metrobus Rapid Bus Transport system is analyzed. The Metrobus equipped with portable emission measurement systems and portable fuel consumption meter is used for measurement activities. Then the results are analyzed in terms of emissions and fuel consumption regarding to the operating parameters. The results showed that the driving behavior has great effect on both emissions and fuel consumption. It was shown that the accumulated emissions near bus stop can strongly affect the public health. The emissions and fuel consumption are both analyzed regarding to the acceleration and speed. The emissions and fuel factors are developed and compared with the values indicated in the literature. It was also analyzed that it is possible to lower emissions with operating the vehicle some certain regions.

Research paper thumbnail of Simulating City-Bus On-Road Operation With VECTO

Frontiers in Mechanical Engineering, 2019

Heavy-duty vehicles constitute a significant contributor to road CO 2 emissions, despite accounti... more Heavy-duty vehicles constitute a significant contributor to road CO 2 emissions, despite accounting for only a low share of the vehicle fleet. CO 2 Emissions certification and monitoring are performed using vehicle simulation software designed for the purpose (VECTO). The European Union currently regulates rigid truck and tractor-trailer CO 2 emissions and subsequently will proceed to buses and other heavy-duty vehicle categories. The current study investigated the use of VECTO on a city bus by modeling the on-road operating conditions of a vehicle in an urban route in Istanbul. The simulation results for constant auxiliary load showed a difference with the on-road measurements in the range of −1.6 to 3.2%, depending on the direction of the route. The difference was attributed to the influence of the total elevation change, and the use of auxiliaries. The latter comprise a significant part of energy consumption in buses, and for this reason, VECTO includes a dedicated bus auxiliary module. The use of the module was also explored, and it was found to improve the results in some cases. The findings highlight the need to assess the operation of auxiliary components in city buses accurately, and to consider the provision of more precise, auxiliary-component specific, information when running actual real-world CO 2 simulations of these vehicles.

Research paper thumbnail of A fuel consumption model for public transportation with 3-D road geometry approach

Thermal Science, 2018

Public transportation fuel consumption modeling shows a great importance because of economic and ... more Public transportation fuel consumption modeling shows a great importance because of economic and environmental aspects. Considering to the metropolises with millions of inhabitants with circulating thousands of buses that uses intercity lines, its importance is becoming vital in planning both operation of transportation company and city mobility planning. In this context a detailed fuel consumption modelling approach for public transportation buses was used for vehicle fuel consumption assessment during operation. The methodology was developed with IPG TruckMaker + AVL Cruise co-simulation environment following instantaneous speed, load and 3-D road data primarily besides model parameters. The model was validated at one of the most important public transportation axle of the world, Istanbul Metrobus System, at two direction which carries over ~1 million passenger daily in 24 hours operation with petrol engine buses. The comparison simulation/measurements showed that the proposed fuel consumption model is accurate and can predict fuel consumption behavior for public transit buses in a reliable band. In addition, this methodology can be used to investigate various powertrain and operating scenarios near future for more efficient public transportation with high reliability.

Research paper thumbnail of Assesment of real driving emissions of a bus operating on a dedicated route

Thermal Science, 2018

The reducing of real driving emissions from public transportation which is using intracity lines ... more The reducing of real driving emissions from public transportation which is using intracity lines has become more important in recent years. This is because the petroleum derived fuel combustion products contributes the global warming as well as adversely the air quality. The fuel consumption perspective is another major economical concern for operating companies that should be optimized. In this context a part of Istanbul Metrobus public transportation system of which is using fully a dedicated line is assessed via on board emission and fuel metering devices for two loading conditions. The relevant vehicle and engine operating data is logged during the tests. The logged data is post processed for developing the average emission factors. The results are also analyzed from acceleration and altitude change perspective and alternative scenarios are discussed for cleaner and economic operation. Lastly the in-service conformity parameters are identified and the results are compared with h...

Research paper thumbnail of Istanbul Metrobus Line Fuel Consumption Optimization via 3D Road Model by Using Avl Cruise Ipg Truck Maker Co-Simulation

INTERNATIONAL JOURNAL OF ADVANCES ON AUTOMOTIVE AND TECHNOLOGY, 2017

Research paper thumbnail of Modelling analysis of multiple diesel injection strategies with one-dimensional simulation coupled with artificial neural networks

Thermal Science, 2017

In the modern Diesel injection systems the phasing of injection in the same cycle gives a high fl... more In the modern Diesel injection systems the phasing of injection in the same cycle gives a high flexibility to engineers from the perspective of engines performance and emission optimization. Basically, the injection is separated in to three phases: the pilot, main, and post injection phases. The focus of this study is based on pilot injection strategy implementation, which can be used for emission control effectively. In this work, reference main and pilot + main injection strategy experiments were realized in a modern Diesel engine. The logged data groups were used to model the engine at 1-D thermodynamic simulation AVL BOOST. In the second stage of this work, the engine operating points which are not realized at test bench are made run at BOOST programme. The new model parameters of simulation are identified with artificial neural network technique. The results showed that the implementation of appropriate mass of pilot injection at the appropriate injection advance will reduce th...

Research paper thumbnail of Effects of soybean biodiesel on a DI diesel engine performance, emission and combustion characteristics

Fuel, 2014

h i g h l i g h t s " Soybean biodiesel and B10, B20, B50 blends were tested with a single cylind... more h i g h l i g h t s " Soybean biodiesel and B10, B20, B50 blends were tested with a single cylinder diesel engine. " Biodiesel showed significant decreases at CO and THC emissions while NO x increased. " Biodiesel usage shortened the ignition delay. " Biodiesel could be used without any modification on diesel engine.

Research paper thumbnail of Experimental study on energy and exergy analyses of a diesel engine performed with multiple injection strategies: Effect of pre-injection timing

Applied Thermal Engineering, 2013

Several studies in the literature treat the effects of ambient conditions and alternative fuel us... more Several studies in the literature treat the effects of ambient conditions and alternative fuel usage on the thermal and exergetic efficiencies of diesel engines. Different from other studies this study investigates the influence of the dwell time of multiple injection events on the thermal and exergetic efficiencies. A test engine was run using three different injection strategies. The main injection timing, the total fuel injected into the combustion chamber per cycle, the engine speed, the rail pressure and the intake manifold pressure were held constant, and the pre-injection timing was varied during the engine tests. Using the results of the engine experiments, the heat release rate, combustion temperature, heat balance, thermal efficiency, and exergetic efficiency were calculated. While it wasn't obtained any significant change in the thermal efficiency, exergetic efficiency and the exergy, the NOx emissions decreased by 7.4% via implementing appropriate pre-injection mass and injection advance. The combustion temperature and cooling heat loss decreased, while the exhaust heat loss increased when using the pre-injection strategies. The results demonstrate that pre-injection strategies, whose main goal is reducing NOx emissions, cause negligible losses in the thermal and exergetic efficiencies.