KONVOY İKİ HAFİF TİCARİ TAŞITIN ARASINDAKİ MESAFENİN YAKIT TÜKETİMİNE ETKİSİNİN SAYISAL İNCELENMESİ

Dünyada enerji eldesi ve tüketimi günümüzün en önemli sorunlarından biridir. Taşıtlarda enerji tüketimi de otomotiv endüstrisinin başlıca odaklandığı konulardandır. Taşıt sayısının artışının ister istemez sebep olduğu konvoy sürüşle enerji tüketimi azaltılabilir. Bu çalışmada, tek hafif ticari taşıt ve farklı taşıtlar arası mesafelerde konvoy iki taşıt için sürükleme ve kaldırma katsayıları sayısal olarak belirlenmiştir. Bu sayısal çalışma bire bir taşıt boyutlarında ve %2,6 blokaj oranında tasarlanan rüzgar tünelinde 90 km/sa hava giriş hızında Realizable k-ε türbülans modeli kullanılarak hesaplamalı akışkanlar dinamiği metodolojisi ile gerçekleştirilmiştir. Sonuç olarak taşıtlar arası mesafe arttıkça iki taşıtın ortalama sürükleme ve kaldırma katsayıları arttı. Konvoy sürüşte taşıtlar arasında mesafe olmaması durumunda tek taşıta göre öndeki taşıtın yakıt tüketimi %26 düşerken arkadaki taşıtın %4 artmıştır

Dynamic simulation of the fuel flow in the carburetor and control with electromechanical systems

Bu çalışmada yakıt sarfiyatını azaltmak amacıyla eski model karbüratörlerin rölanti devrelerinde bazı yapısal değişikliklerin yapılması amaçlanmıştır. Bununla ilgili temel işlem olan, rölanti devresindeki akış orjinal ve imal edilen solenoid valflerle kontrol edilsi. Eski model bir karbüratörün rölanti devresinin gerçek boyutlardaki bir pleksiglas(şeffaf) modeli imal edilmiş ve bunun üzerinde deneyler yapıldı. Ayrıca rölanti kanalındaki akış gözlendi. Gerçek motor üzerinde yapılacak deneyler için bilgisayar ile motor arasındaki elektronik devreler hazırlandı ve veri toplama kartını çalıştıracak program C++ dilinde yazıldı. Son olarak yeni tasarımla deneyler yapıldı, elde edilen sonuçlar diğer model sonuçları ile mukayese edildi.In this study it is aimed to apply some constructional modifications to idle systems of old model classical carburetors to improve the fuel consumption. Flow in idle running system is controlled with original (used in modern carburetors) and newly manufactured solenoid valves. A plexiglass model carburetor having original dimension of idle running system of an old real carburetor is manufactured and then some experiments are carried on this new model. Furthermore, flow in the channel of idle running system is physically examined. Electronic circuits between computer and internal combustion engine are completed a computer program which runs the data acquisition cards is C++. Finally, experiments are carried out with new design and data obtained is compared with the results of other models

FATIGUE ANALYSIS OF AN AUTOMOBILE REAR AXLE BY USING FINITE ELEMENT METHOD

In this study, stress analysis of a native automobile axle exposed to wheel loads is performed and the location of maximum stresses occurring on the axle is determined. Then, it is controlled whether these stresses exceed the limit values or not. In addition, fatigue life of the axle is calculated under selected loads by using finite element method based fatigue analysis. It is shown that the most critical locations on the axle are the regions near to chassis connection points

Development and comparative analysis of a pure fuel cell configuration for a light commercial vehicle

Fuel cell electric vehicles help hybrid and battery electric vehicles to reduce vehicle emissions. Fuel cells are more appealing since, like internal combustion engines, they provide energy as long as fuel is supplied while doing so with less energy conversion and little or no emissions. In this study, the energy and fuel consumption values of a vehicle's internal combustion engine and fuel cell configurations were compared on a tank-to-wheel basis. First of all, a fuel consumption model was created for the conventional vehicle with 1.3 diesel engine. Subsequently, the fuel cell configuration of the same vehicle was designed by selecting a suitable fuel cell, electric motor, battery, and transmission. Then, the fuel cell vehicle configuration's hydrogen and energy consumptions were calculated. The equivalent diesel consumption of the fuel cell vehicle was determined to be 3.38 L/100 km at the end of the study, which is 32% better than an Internal Combustion Engine vehicle. Also, with theoretical regenerative braking in the fuel cell electric vehicle, consumed traction energy can be reduced by 27%, while with practical regenerative braking, 55% of the braking energy can be recovered, and the traction energy can be reduced by 15%. On the other hand, since there is no regenerative braking system in the conventional vehicle, all of the braking energy is lost as heat

Experimental investigation of performance and emission improvement by altering ignition timing with use of E10 ethanol blend in SI engine

In this study, the best ignition timing for an SI engine with the use of E10 ethanol blend was experimentally investigated. Ignition timing was retarded successively by 2 degrees up to 6 degrees at most (denoted as -2, -4 and -6 respectively) and then advanced by 2 degrees successively up to 6 degrees (denoted as +2, +4 and +6 respectively) with respect to the advance values realised with gasoline (termed as 'original advance values') at full load operation. It was generally observed that overall efficiency increases with advanced ignitions. The best performance and emissions were obtained with +4. This increase amounts to 6% for 4 degrees advanced ignition at 3000 rev min(-1). Advanced ignition timing resulted with increase in NOx emissions, while CO and CO2 remained relatively unaffected. Increasing retard in ignition timing caused poorer combustion and hence more fuel consumption but less hydrocarbon emissions

Development of dual polarization battery model with high accuracy for a lithium-ion battery cell under dynamic driving cycle conditions

Lithium-ion batteries are a key technology for electric vehicles. They are suitable for use in electric vehicles as they provide long range and long life. However, Lithium-ion batteries need to be controlled by a Battery Management System (BMS) to operate safely and efficiently. The BMS continuously controls parameters, such as current, voltage, temperature, state of charge (SoC), and state of health (SoH), and protects the battery against overcharging and discharging, imbalances between cells, and thermal runaways. The battery models and several prediction algorithms that the BMS uses to carry out these checks are essential to the system's performance. This research assesses the Dual Polarization (DP) model's ability to mimic actual battery performance in different dynamic driving conditions. In the study, a battery model for a Lithium–Nickel–Manganese–Cobalt-Oxide (Li-NMC) cell with a nominal capacity of 2 Ah is developed. A DP model was used in the study. Modeling and parameter estimation were performed in MATLAB Simulink/Simscape. Firstly, the model parameters are estimated depending on the SoC using the current and voltage data obtained from the Hybrid Pulse Power Characterization (HPPC) test. A further validation study of the model for low dynamic and high dynamic driving cycles is then presented. Dynamic Stress Test (DST), the US06 Supplemental Federal Test Procedure (SFTP) and Worldwide harmonized Light vehicles Test Procedure (WLTP) cycles were used for model validation. As a result of the study, the model's Root Mean Square (RMS) error values were obtained as 0.0053 V for DST, 0.0059 V for US06, and 0.008 V for WLTP. The obtained model is particularly successful for simulating a battery under dynamic current conditions and for use in control and prediction algorithms

Numerical investigation of the spray characteristics in an outwardly-opening piezoelectric gasoline injector for different ambient conditions

In this study, the spray characteristics of an outwardly-opening injector have been investigated numerically. Numerical analyses are carried out by taking temperature and pressure statuses of the internal combustion engine in cold temperature operations into consideration. The effects of these parameters on the evaporation rate, penetration, spray morphology, angle of the fuel spray and the Sauter Mean Diameter were key issues to be addressed. N-heptane fuel was used and the Kelvin-Helmholtz / Rayleigh-Taylor breakup model was adopted. The analyses were performed in the comprehensive environment of Fluent software. It was observed that the results complied with experimental data taking part in literature. Consequences demonstrated that increasing the ambient pressure intensified vortex formation, decreased penetration and increased fuel cone angle by forming a more compact fuel bundle. In addition, it was ascertained that theeffect of the temperature parameter on the evaporation was less effective than the pressure parameter