Hybrid vehicle design, supporting renewable alternative energy sources and simulation

In this thesis, internal combustion engines and propelling systems of new vehicles, affects of air pollution and neccessity of hybrid technology vehicles worked and analysed. Growing world population and their energy needs especially in production, electricity production and logistics needs causes dangerous gas emmisions affect environment. Furthermore, fossil fuels will be consumed totally in the next 50 years. In this thesis, hbyrid electric vehicles' general definitons, applications and their technologies investigated and studied. Internal combustion engines, hbyrid electric series, paralel and series/parallel vehicles worked and explained in detailed. Alternative energy systems like wind energy solar energy and exhaust turbine energy worked and added to usual hybrid vehicles. At the beginning of this thesis, enviromental approach of vehicles, exhaust gas emmisions, petrol consumption and internal combustion engines are given in detailed study. Enviromental effects and air pollution will be very harmful and problemeatic issues in the future. %30 percent of air pollution and gas emmisions are maden by motor vehicles and transport industry. Exhaust gas and poisonous chemical compounds like CO, Nox etc are very dangerous for natural life, environment and Human health. Thus, enviromental effects are very important for vehicle design, engine design and alternative energy support systems. European standards for motor vehicles and exhaust gas emmisions are getting narrow step by step for near future. In passenger cars, CO emmision standard will be 95 gr/km as of 2020 according to Euro 6 standard regulations. Decreasing exhaust gas emmisions and depending on this case, decreasing fossil fuel consumption of motor vehicles are getting more important for near future. As explained in this thesis, hybrid electric vehicles are the first step to electric vehicles. The vehicles with electric propulsion are limited usage due to long time charging process and very low range compared to conventional vehicles with internal combustion engines. Hybrid electric vehicles are vehicles use minimum two different methods and energy systems for propulsion. They are mostly a combination of internl combustion engine and electric motors. Hybrid vehicles are also threshold for fuel cell technology that uses chemical energy. A hybrid vehicle uses two different sources of tractive energy e.g. a fossil fuel and electricity that together, or one at a time can be used for vehicle propulsion. A hybrid vehicle or gas-electric hybrid powered vehicle uses a mixture of technologies such as internal combustion engines, electric motors, gasoline, and batteries. Today's hybrid cars are driven by electric motors powered by both batteries and an ICE. In an ICE based HEV, the engine is coupled with electric machine. This modification creates integrated mechanical and electrical drive trains that merge power from both the ICE and the electric motors to drive the vehicle. By using the energy storage system as a power buffer, the ICE can be operated at its most efficient condition and reduced in size while maintaining the overall performance of the vehicle. In this type of vehicles, fossil fuel, however, is still the sole energy source to the vehicle system, (except for plug-in HEV where electricity obtained from electrical grid provides another power source). The charge of the battery is maintained by the ICE and the electric machines. As a consequence of the reduced engine size, more efficient engine operation, and recovered braking power, fuel usage and emissions of the vehicle are considerably lower than comparable conventional vehicles. In this thesis, Chapter 1 has defined the research problem and presented the importance of the HEV technology. Classifications of various HEV configurations were introduced based on different criteria. Chapter 2 explains the power and energy demands from vehicle on board energy storage system. Based on these demands, a review on recent advances of HEV related energy storage system technologies were presented. Chapter 3 discusses the state-of-the-art of HEV design and simulation tools. Two widely used modeling platforms are discussed in details. Chapter 4 explains the modeling of hybrid power system for a hybrid electric vehicle. Chapter 5 explains design of hybrid electric vehicle with support of wind energy, exhaust turbine energy and solar energy. ECE R15 and EUDC road simulation datas will be used for road conditions, acceleration and stopping functions. In 1970s, many auto makers such as GM, Ford and Toyota started to develop electric vehicles powered by batteries due to the oil shortage. However, these electric vehicles powered solely by battery power did not go far enough. The interest in hydrogen fuel cell cars has arisen as a result to address the range problem associated with battery power cars. However, with more than 15 years of intensive development, there are still not any fuel cell hybrid cars on market mainly due to the high manufacturing cost. In the meantime, other automotive manufacturers have moved in another direction of internal combustiın engine based hybrid electric vehicle. In 1997, Toyota introduced the the first internal combustion based hybrid electric vehicle to the Japanese market. Ever since, an increasing number of HEV have become available. One of the most common ways to classify HEV is based on configuration of the vehicle drivetrain. In this section, three major hybrid vehicle architectures introduced are series, parallel and series-parallel. Until recently, many HEV in production are either series or parallel. In terms of mechanical structure, these two are primitive and relatively simple. A series-parallel powertrain brings in more degrees of freedom to vehicle engine operation with added system complexity. Simulation based analysis on vehicle performance is crucial to the development of hybrid powertrain since design validation using costly prototype is impractical. Due to the inconvenience of the many separated modeling methods, integrated modeling tools are required to speed up the modeling process and to improve the accuracy. Vehicle simulation is a method for fast and systematic investigations of different design options (fuel choice, battery, transmission, fuel cell, fuel reformer, etc.) in vehicle design and development. At present, several simulation tools based on different modeling platforms are available, although none of them is sufficient to model all design options. These tools always focus on a specific application with focused concerns. At the beginning of simulation, conventional hybrid series-parallel configuration vehicle's simulation is maden. Charts and simulation results are evaluated. In results, avarage fuel consumption, internal combustion engine and electric motors on/off modes, torque, total power needed for road simulation and state of charge cases of battery are evaluated. State of charge value of %60 in battery charging, the system starts producing electricity and charging battery. Our aim is keeping the battery %60 percent level of full charge all the time. Furthermore, additional features like wind energy turbines, exhaust energy turbines and photovoltaic solar panels applied to the vehicle energy system. Wind turbines are placed at the front fog lamps' position. These turbines produce electric energy while having wind from front section according the speed profile of the vehicle. Relative speed is same with vehicle's speed while in negative acceleration. In positive acceleration wind turbines are off mode. ECE R15 road conditions have 4 times stopping and also negative acceleration. Wind turbines charge battery while in negative acceleration and they provide % 0,8 fuel consumption gain compared to conventional vehicle. This Hybrid vehicle has also 54 pcs solar panel ( photovoltaic cells) at the roof. Avarage radiation value is defined for solar energy and applied in Matlab Simulink simulation in order to have electric charging. Solar energy provides %2 fuel consumption gain compared to conventional vehicle. Exhaust energy is produced by exhaust gas pressure created by engine piston movement and also chemical reaction's pressure difference. Turbocharger unit is applied in exhaust system and 60000 rpm speed turbine is selected. Speed is decreased to 3000 rpm by the help of reducer. The reducer also provide torque increase and turns on electric generator. Electric generator generates power to the battery. Exhaust turbine energy provides % 0,45 fuel consumption gain. All of these alternative energy systems are used for charging battery alternatively. According to simulation results, tha gap between conventional hybrid vehicle and alternative energy supplied hybrid vehicle can be seen. Fuel reduction is about % 3,86 according to simulation results. The most efficient method is solar energy when compared with wind energy and exhaust turbine energy. Solar energy is an external power source that do not cause any case of inefficiency. Wind turbine can run just in negative acceleration. If they run in all road conditions, wind turbines cause extra wind resistance. So, wind energy would decrease total efficiency of the vehicle. In order to solve total efficiency problem, wind turbines will run just in negative acceleration modes. All of these energy systems will be stored in battery. Wind turbines and exhaust energy turbines produce AC voltage and solar energy produce DC voltage. All of these energy sources will be converted DC to DC and enters battery after DC Bus converter. Power management system comtrols all electrical algorithm and additional energy sources like wind, solar and exhaust energy. Fuel efficiency and fuel consumption calculations have been maden with engine characteristic curves affected by engine rpm and specific fuel consumption values for engine revolution per minute. Avarage fuel consumption in conventional hybrid electric vehicle is about 4,595 L per km and in alternative energy sources supported hybrid vehicle's consumption is 4,418 L per km. That means fuel efficiency provided as about % 3,86 totally. Relative speed assumed that it's same with vehicle speed and there is no wind speed. In solar energy, avarage solar radiation value is taken. In exhaust enegy system, pressure difference is directly used in turbine. As a result, alternative energy supported hybrid electric vehicles are efficient systems that include wind, solar and exhaust systems. Wind energy and solar energy are renewable sources that World needs for the future. These systems are applied to hybrid electric vehicles and the total efficiency increased. In the future, more efficient turbines and more efficient solar panels and exhaust turbine generators can be used and total efficiency can be increased.