Dr. Ali Mirmohammadi, Eng. Mehdi Rezaei-Ravari,
Volume 11, Issue 1 (3-2021)
Abstract
In this article, the procedure of series hybridizing is fulfilled on the O457 city bus that is produced in Irankhodro Diesel Company. For simulation validation the bus with base diesel engine is simulated in European and Tehran compound urban–highway driving cycle and fuel consumption results compared. First the ECE_EUDC_LOW driving cycle simulation results compared with the results of the advisor software that was some difference between two software results. For deep validation bus with base engine was simulated in Tehran driving cycle and fuel consumption calculated 53.26 Lit/100Km that was near actual value that is 59.48 Lit/100Km. After verification, a bus with series hybrid electric-diesel powertrain was designed and simulated in the European and Tehran driving cycle. Simulation results and experimental data’s shown that the series hybrid electric-diesel bus fuel consumption reduction in the ECE_EUDC_LOW driving cycle, is 30% and in Tehran driving cycle is 39% less in comparison to base power train that is base diesel engine.
Hossein Gharaei, Pouria Ahmadi, Pedram Hanafizade,
Volume 11, Issue 1 (3-2021)
Abstract
This paper introduces a novel powertrain system composed of a liquid ammonia internal combustion engine, a dissociation and separation unit, and a PEM fuel cell system developed for vehicular applications. Using a carbon-free fuel for the ICE and producing hydrogen on board for PEMFC use significantly enhance this novel systemchr('39')s environmental effects. The thermodynamic analyses are conducted using EES and MATLAB software. The results show that while this hybrid powertrain system produces 120 kW output power, energy and exergy efficiencies are 45.2% and 43.1%, respectively. The overall exergy destruction rate of the system becomes 237.4 kW.The fuel consumption, engine speed, and battery state of charge (SoC) analyses are calculated using three driving cycles. These vehicles consume 7.9, 5.7, and 7.7 liters of liquid ammonia per 100 km in FTP-75, NEDC, and HWFET driving cycles, respectively. The battery state of charge differentiation in these three cycles shows the practicality of this novel powertrain system specially in inner-city driving cycles as the battery does not confront any intense decline of SOC to the minimum level. HWFET results show the great dependence of the vehicle on ICE and low PEM fuel cell function, which results in releasing decomposed hydrogen to the environment.
Sohrab Pakdelbonab, Afshin Kazerooni, Gholamhassan Payganeh, Mohsen Esfahanian,
Volume 11, Issue 1 (3-2021)
Abstract
Global restrictions on the use of fossil fuels in the transportation sector and the commitment to rapid response to the climate change have created a strong incentive to develop fuel-efficient and low-emission vehicle systems. Hydraulic hybrid power train technology is one of the temporary solutions introduced to optimize internal combustion engine (ICE) operation and regenerate braking energy. The hydraulic hybrid power train system (HHPS) has a higher power density than the electric one. So, it is used in heavy vehicles, agricultural and construction machinery that need a high-power density to accelerate or recover the braking energy. In some trucks, such as refuses collection trucks, fire trucks and delivery trucks, a high percentage of the ICE energy is consumed by the auxiliary systems. In this type of trucks, the hydraulic hybrid power train systems are not very efficient. This paper introduces a hydraulic hybrid auxiliary system (HHAS) concept to manage the energy consumed by the auxiliary system in refuse collection trucks. In the first part of the paper, the configurations and operating modes of series, parallel and hydro-mechanical HHPS are discussed and compared with the HHAS concept. In the following, the conventional refuse collection truck model and refuse truck equipped with HHAS model was developed in MATLAB/SINMULINK and simulated in Tehran refuse collection truck driving cycle. The simulation results show that by using the HHAS concept, the fuel consumption is reduced by 15 percent.
Mr, Mohmadreza Sabzehali, Mr, Mahdi Alibeigi, Dr. Somayeh Davoodabadi Farahani,
Volume 11, Issue 2 (6-2021)
Abstract
In this study, a new micro gas turbine engine is presented. The effect of inlet air cooling on the performance of the micro gas turbine engine by changing the parameters such as the temperature difference between the inlet air temperature (IAT) based on ISA (International Society of Automation) standard and turbine inlet temperature (TIT) has been investigated. then, an Optimization is done base on the Genetic Algorithm with two separate objectives, SNOx minimization, and Thermal efficiency maximization, separately. The thermal efficiency and specific consumption of the optimized cycle based on the thermal efficiency are compared with the XU7/L3 internal combustion engine to produce the output power of 64.57 KW. Results show by adding a cooling system to the micro gas turbines to cool the inlet air with the coefficient performance of 2 and 4 increased the thermal efficiency by about 11.37% rather than base mrio gas turbine engine Eventually, the proposed micro gas turbine engine is more efficient than the XU7/L3 internal combustion engine. so It can be understood that micro GT is one of the best substitutes for the internal combustion engine in the new vehicle age just by adding the cooling system.
Hojjat Ashouri,
Volume 12, Issue 3 (9-2022)
Abstract
Loading conditions and complex geometry have led the cylinder heads to become the most challenging parts of diesel engines. The aim of this study is to compare the distribution of temperature and stress in the aluminum and magnesium cylinder heads under thermo-mechanical loads. The three-dimensional model of the cylinder heads was simulated in abaqus software and a two-layer viscoplasticity model was utilized to investigate the elastic, plastic and viscous behavior of the cylinder heads. The temperature and stress results of magnesium alloy was compared to aluminum alloy results. The results of finite element analysis (FEA) showed that surface temperature of the magnesium cylinder heads is about 23°C lower than the aluminum cylinder heads. As a result, the fatigue lifetime of the magnesium cylinder heads can be improved in comparison to the aluminum cylinder heads. The thermo-mechanical analysis showed that the magnesium cylinder heads tolerate less tensile and compressive cyclic stress compared to the aluminum cylinder heads. The stress reduction value in the magnesium cylinder heads was about 10 MPa which can lead to higher fatigue lifetimes in comparison to the aluminum cylinder heads.
Dr Morteza Mollajafari, Mr Alireza Rajabi Ranjbar, Mr Shayegan Shahed Haghighi,
Volume 12, Issue 3 (9-2022)
Abstract
The development and adoption of electric vehicles (EVs) appears to be an excellent way to mitigate environmental problems such as climate change and global warming exacerbated by the transportation sector. However, it faces numerous challenges, such as optimal locations for EV charging stations and underdeveloped EVCS infrastructure, among the major obstacles. The present study is based on the location planning of charging stations in real cases of central and densely populated districts of Tehran, the capital of Iran. In order to achieve this goal, this paper attempts to validate the results of a previous study in another country. Secondly, by employing preceding principals in accordance with relevant information collected from the car park and petrol stations in the regions of study, a five-integer linear program is proposed based on a weighted set coverage model considering EV users' convenience, daily life conditions, and investment costs, and finally optimally solved by genetic algorithm under various distribution conditions; normal, uniform, Poisson and exponential, to specify the location and number of EV charging stations in such a way that EV drivers can have access to chargers, within an acceptable driving range.
Dr. Hossein Bagherian Farahabadi, Mr. Amirhossein Pahnabi, Mr. Reza Youneszadeh, Dr. Mohammad Ali Alirezapouri, Mr. Mohammad Rezaei Firuzjaei,
Volume 13, Issue 1 (3-2023)
Abstract
One of the most important components of fuel cell power systems is the power conditioning subsystem. DC/DC converters play the leading role in the power conditioning subsystem and fuel cell hybridization with other electric power sources and storage. DC/DC converters control the load voltage and, in some cases, the fuel cell current, while current-controlled DC/DC converters control the loading level. Some advantages of designing converters in a multi-layer topology include reduced input current ripple and increased power density. Lower current-rating semiconductor devices can be used due to the current division among the layers and lower values of inductors and capacitors can be used due the lower input current and output voltage ripples, respectively. Furthermore, failure of one layer does not result in a complete system outage; the other layers can deliver a fraction of the nominal power. A fuel cell power system based on a 16 kW proton exchange membrane fuel cell stack and a multi-layer DC/DC boost converter is designed and implemented in this paper. The power system is intended for marine air-independent propulsion systems. The power system is modeled and analyzed using the MATLAB/Simulink software environment. The power system is implemented to verify the analysis and simulation results.
Mahdi Khoorishandiz, Abdollah Amirkhani,
Volume 13, Issue 1 (3-2023)
Abstract
As electric vehicles become more popular, we need to keep improving the lithium-ion batteries that power them. Electrochemical impedance spectroscopy (EIS) is used based on a discrete random binary sequence (DRBS) to reduce excitation time in the low-frequency region and excite the input of the battery. In this paper, voltage and current signals are processed with wavelet transform for impedance evaluation. In using wavelet transform, choosing the most optimal mother wavelet is crucial for impedance evaluation since different mother wavelets can produce different results. We aim to compare three types of continuous Morse mother wavelet, continuous Morlet, and continuous lognormal wavelet, which are among the most important mother wavelets, to determine the best method for impedance evaluation. We used the dynamic time-warping algorithm to quantify the difference between the initial values obtained from standard laboratory equipment and the impedance evaluation through three different continuous wavelets. Our proposed method (lognormal wavelet) has the lowest difference (3.4086) from the initial values compared to the Morlet (3.5504), and Morse (3.5457) methods. As a result, our simulation shows that the lognormal wavelet transform is the best method for impedance evaluation compared to Morlet and Morse wavelets.
Dr Mohammad Mahdi Taskhiri,
Volume 13, Issue 3 (9-2023)
Abstract
This paper presents an inhomogeneous lens to radiate a control-table Fan Shaped pattern for long-range automotive applications. Fan Shaped pattern of the designed lens covers more angles in azimuth. The proposed circular aperture inhomogeneous lens is designed based on the critical angle theorem. The profile of the dielectric constant of the proposed lens changes in 3 directions of ρ, φ, and z. The lens is matched to the source and surroundings. A closed-form formula is offered for an arbitrary fan-shaped pattern lens antenna. A compact circular lens with a diameter of 20 mm and thickness of 2.25 mm is simulated in CST full-wave software to validate the design structure.
Mr. Hosein Hamidi Rad, Prof. Mohsen Esfahanian, Prof. Saeed Behbahani,
Volume 13, Issue 3 (9-2023)
Abstract
This study examines the impact of a fuzzy logic-based control strategy on managing peak power consumption in the auxiliary power unit (APU) of a hybrid electric bus. The APU comprises three components: an air compressor, a power steering system, and an air conditioning system (AC) connected to an electric motor. Initially, these components were simulated in MATLAB-SIMULINK software. While the first two were deemed dependent and independent of vehicle speed, respectively, the stochastic behavior of the steering was emulated using the Monte Carlo method. Subsequently, a fuzzy controller was designed and incorporated into the APU to prevent simultaneous operation of the three accessories as much as possible. The results of repeated simulations demonstrated that the designed fuzzy controller effectively distributed the operation of the accessories throughout the driving cycle, thereby reducing overlaps in auxiliary loads. Consequently, the APU's average and maximum power consumption exhibited significant reductions. Furthermore, through multiple simulations with an upgraded power system model integrating the new APU-controller package, it was established that the proposed strategy for managing auxiliary loads in the bus led to lower fuel consumption and emissions.
