Problem StatementFor the past seventeen years, the U.S. Department of Energy (DOE) has sponsored over twenty competitions to develop more efficient vehicles. The contests challenge engineering students to develop vehicles, which are more fuel-efficient and produce lower emissions while maintaining safety, performance, and consumer appeal of a variety of different vehicles [1]. General Motors Corporation (GM), DOE, and other government and industry leaders have recently developed a competition called Challenge X. This three-year competition will give twelve engineering schools an opportunity to participate in hands-on research and development with automotive propulsion, fuels, materials, and emissions-control technologies [1]. The specific goal of the competition is to re-design a GM Equinox to minimize energy consumption, emissions, and greenhouse gases while maintaining or exceeding the vehicle's utility and performance. The main purpose for the first year is to focus on modeling, simulation, and testing of the vehicle’s powertrain and vehicle subsystems [1]. This competition allows each team to engineer their own design in order to meet or exceed the original operating parameters of the GM Equinox. The electric motor team is specifically designing the motor configuration that will be used for the competition in driving the powertrain and regenerating the batteries. The chosen configuration must provide the most reliable, efficient conversion between electricaland mechanical energy possible. For this project Mississippi State University’s CAVS (Center for Advanced Vehicular Systems) has decided to use a diesel-electric hybrid vehicle. The competition focuses on the design and development of this diesel-electric hybrid vehicle to minimize consumption of fossil fuels and restrict the pollutants associated with the bi-products of fossil fuels.Studies show a significant increase in the purchasing of Sports Utility Vehicles (SUVs) over the past few years. SUVs of today are normally powerful, heavy vehicles with very poor gas mileage. GM and the DOE have devised this competition to design an SUV with the same power of other SUVs, but with a better gas mileage record. A solution to the problem is to design a hybrid vehicle. The problem with most hybrid vehicles is not that they lack fuel efficiency; it is that they are not very powerful and stylish. When most people think of a hybrid vehicle they think of a car the size of a sardine can. Consequently, not many people purchase these hybrid cars. GM and the DOE created the Challenge X program to lean more toward a consumers need for a big powerful vehicle. The main problem is to design a hybrid SUV to be powerful, but not rely heavily upon fossil fuels. The price of gasoline is still on the rise and does not appear to be coming down anytime soon. Even if the price of gasoline does come down it is more than likely to go right back up. For example, as recently as four years ago, OPEC set oil prices per barrel at twenty two to twenty eight dollars, only to nearly double this price two years later. Every dollar increase results in almost two and a half cents per gallon at the pump. To cut down on the dependence of fossil fuels car manufactures have developed hybrid vehicles, which are a combination of internal combustion engines (ICE) and electric motors. The first problem with this is to determine the type of configuration to drive the vehicle. There are two main types of configurations a parallel and a series. The parallel configuration uses both the electric motor and the ICE to drive the vehicle. In other words it splits the responsibility of propelling the vehicle between the ICE and electric motor. The series configuration relies solely on the electric motor to turn the wheels of the vehicle, and the ICE is used to recharge the battery pack that powers the electric motor.After the configuration is chosen, the proper electric motor needs to be chosen. The department staff of CAVS (Center for Advanced Vehicular Systems) chose to use a parallel configuration. The Equinox will use a diesel engine for the ICE. There are two different options when choosing an electric motor. There is an AC induction motor and a DC permanent magnet motor. The AC induction motor is very rugged and dependable, but does not have very good regenerative properties. The DC permanent magnet motorhas excellent regenerative properties, but is not as rugged as the AC induction motor. The possibility of using the AC induction motor to power the vehicle and a smaller DC permanent magnet motor to rechargethe batteries is also possible. After testing and simulation, a motor with the requirements must be chosen. For the Challenge X competition a ninety to one hundred horsepower motor is required in order for the overall diesel-hybrid combination to meet standards of the competition. The motor will also have to be at least seventy five percent efficient, with a load, in order for the fuel mileage and emissions requirements to be met. Once several motors with these specific requirements are found, it will be required to fit underneath the hood orpossibly under the vehicle. Space will be limited due to the ICE and the battery pack being under the hood as well as the electric motor. The addition of the electric motor must take the overall weight into consideration. If the vehicle’s weigh is changed significantly, there might be a reduction in performance and in the vehicle’s fuel mileage capability. Once a motor is chosen then the problem of controlling the motor comes in to play. A controller device will need to be placed along with the motor to keep it in line with the ICE. The controller will be used to measure how far the driver of the vehicle has pressed the pedal. It will serve the same purpose as electronic controlled fuel injectors. The controller will pass less or more current to the motor to control the electric motor’s output. After selecting a controller the powering of the motor will need to be assessed. The battery packs can only provide two hundred and seventy seven volts, and electric motors used for this application require five hundred seventy volts to operate. A transformer or some other method will need to be used in order to get the proper voltage to the electric motor. The power supply from the battery pack will also need to be made into three-phase power. There are four battery packs, which means that
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