Term Project

Electrical Vehicle: The car of a future

Olga Ozhereleva
Professor Di Credico
RHYS 1132
December 3, 2013

Electrical Vehicle:
The car of a future
In all times and among all nations transport have been playing extremely important role. Today, the existence of any country is impossible without transport network. In the twentieth century, especially in the second half, huge changes have occurred in all countries of the. Population growth, increased consumption of material resources, urbanization, technological revolution, and natural- geographic, economic, political, social, and other fundamental factors have led to the fact that the transport network of the world has received unprecedented growth. Along with the growth of the numbers of vehicles produced, conventional forms of transport undergo radical reconstruction: speed was increased, design was changed, efficiency enhanced, more cars became available for people with different financial positions. At the same time some transport problems have emerged. These problems caused mostly by excessive development the automotive industry. Hypertrophied fleet of large cities in Europe, Asia and America is causing constant traffic jams on the streets. Moreover, these problems deprives citizens of the advantages of fast and maneuverable way of moving. The most important aspect of rapidly grooving production of vehicles seriously degrades the environment. Transport as a particularly dynamic system has always been one of the first “customers” for the discoveries and achievements of various sciences, including fundamental. It is difficult to come up with a field of research that have no relation to transport. Fundamental research in sciences such as mathematics, physics, mechanics, thermodynamic, fluid dynamics, optics, chemistry, geology, astronomy, hydrology, biology have particular importance for its progress. The results of applied research conducted in the field of metallurgy, engineering, electromechanical , structural mechanics, telemetry, automation, and more recently, electronics and aerospace were needed to design and construct vehicles.
Further progress requires the use of the latest, continuously updated results of science, advanced engineering and technology. Striving to increase the speed and frequency of transport units, need to improve comfort and reduce the cost of transportation - all this requires not only improvement of existing vehicles, but also finding new ways that could better meet the requirements than traditional modes of transport. To date, several new types of vehicles developed and implemented in the form of permanent or pilot plants operating and much more exists in the form of projects, patents or just ideas. It should be borne in mind that most of the new modes were proposed many years ago, but they had not received the application and now re- offered or revived by modern technical basis. Electric Vehicle is a vehicle driven by one or more electric motors powered by an autonomous power source (battery, fuel cell, etc.) instead of a combustion engine. EV should be distinguished from electric vehicles with an internal combustion engine and electric transmission, as well as trams and trolleybuses. EVs include plug-in electric cars, hybrid electric cars, hydrogen vehicles, electric trains, electric lorries, electric airplanes, electric boats, electric motorcycles and scooters and electric spacecraft. In this project I am going to talk about fully electric cars, so talking about electrical vehicles I will imply only cars. Electrical vehicle first appeared in England and France in the early 80's of the nineteenth century that is earlier then cars with internal combustion engines. A cab constructed in 1899 by I.V.Romanov, was also an electric vehicle. Traction motor in such machines got power from lead-acid batteries with an energy of only 20 watt- hours per kilogram. In general, a lead battery with a mass of 1 ton was required to feed the engine with a capacity of 20 kilowatts per hour for one hour. Therefore, with the invention of internal combustion engine ICE vehicles production was rapidly gaining momentum, and people forget about electric cars before the serious environmental problems emerged. These problems were caused by toxic substances that internal combustion engine emitted in large quantities to the atmosphere. To solve these particular problems we need to reduce emissions, especially carbon monoxide and dioxide, simultaneously having a huge volume of production of cars. Scientists who conducted a number of studies have identified several solutions, one of which is the production of electric vehicles. In fact, this is the first technology, officially received the status of zero emissions, and already presented in the market. Why are electric cars becoming so attractive and popular? Primarily, it provides almost no emission of harmful substances. The amount of poisonous gases released into the atmosphere during charging and discharging of the battery, much less than by the internal combustion engines. However, to heat electric car in the winter, customers use autonomous heaters that consume gasoline or diesel fuel. Nevertheless, they does not pollute the atmosphere as much as the internal combustion engines. The second advantage is the simplicity of the device. The electric motor has a very attractive feature; at low rotational speed, it has a high torque, which is very important when you need to pull away or overcome a difficult stretch of road. ICE develops its maximum torque at medium engine speeds, so you need a big effort; therefore, it is necessary to increase it with the gearbox. Consequently, it is easier to manage electric car than a car with a manual transmission. The third advantage comes from the second. Electric vehicle does not require such meticulous care as a conventional car; less adjustments, does not consume a lot of oil, simpler cooling system and absence of fuel system (except heating).
Yet the electric car is designed not as easy as it may seem; it requires complex voltage converters and many heavy and bulky batteries that are difficult to place. However, the main drawback, which hinders the introduction of electric vehicles, is low power consumption of batteries. For example, tank with gasoline weighs about 50 kg, providing a power reserve of more than five hundred kilometers. Batteries typically weigh more than 100 kg (or even several hundreds), and run typically (not for all, but for most) does not exceed 100 km, and when driving at low speed.
Contrary to popular belief about the high economy of battery of electric vehicles, the analysis shows that the chemical energy of the fuel burned in power plants, used to move the vehicle by only 15 % or less. This is due to energy losses in transmission lines, transformers, converter and chargers devices for accumulators, electric machine, both in traction and in generator mode, as well as in the brakes if you cannot recover energy. For comparison, a diesel engine optimally converts the mechanical energy of approximately 40% of chemical energy of fuel. With a large spread of battery electric vehicle, they simply will not have enough electricity generated by all power plants in the world. We should not forget that the total installed capacity of all the electric cars exceeds the capacity of all power plants in the world.
Problems can be solved when electric cars are powered by primary energy sources that produce energy directly from the fuel primarily such sources are fuel cells that consume oxygen and hydrogen. Oxygen may be withdraw from the air and the hydrogen can be stored in compressed or liquefied form, but also in hydrides. However, it is more real to derive it from a conventional automotive fuel directly on the electric vehicle using the converter. Efficiency of fuel cells is reduced. Efficiency of fuel cells is still very high, about 50 %.
However, electric -powered fuel cells are not deprived of the total lack of high weight of traction motor that is used for the maximum power and torque as well as the maximum speed. Then the specific shortcomings of the fuel cell appear. Firstly, this is the impossibility of recovering of energy during braking because the fuel cells are not rechargeable, i.e. they cannot be charged with electricity, and secondly, the low power density of fuel cells.
With huge energy density fuel cells (about 400 - 600 Wh / kg), the specific power at economical discharge does not exceed 60 W / kg. This makes a mass of fuel cells for the real capacity (needed for vehicles) very large. For example, for an electric vehicle with a maximum power demand of 100 kW and an electric bus with maximum power demand of 200 kW correspond to the mass of fuel cells of 1670 and 3330 kg, respectively. If we add the mass of traction motors, approximately equal 150 and 400 kg, respectively, we will have the masses of powertrains, unacceptable for electric cars, and requiring a five-ton trailer for electric bus. Scientists attempt to reduce the weight of the fuel cell using compensator energy storage as the intermediate energy storage that have a high power density. However, this way is not efficient enough, as the best modern condensing drives that are available for automotive vehicles have specific energy indicators about 0.55 Wh / kg and 0.8 Wh / liter. In this case, for the accumulation of 2 kWh of energy (this is recommended by experts for electric vehicles, as well as for electric buses), would require about 3000 kg capacitors, which is unrealistic. Smaller values of the stored energy significantly reduce the dynamic quality of the vehicle. Usage of Flywheel Energy Storage that is connected with reversible electric car is much more effective. Flywheel Energy Storage is a flywheel made of wound fibers or ribbons that is put on the elastic center. Specific energy of Flywheel Energy Storage is bigger than the values of this parameter for the best solid flywheels, besides it has the property safe gap, not giving fragments.
Such schemes are implemented in the latest prototypes of hybrid electric cars companies such as Mechanical Technology Inc. (USA), EDO Energy (USA). Specific energy of Flywheel energy storage that are made of graphite, reaching hundreds of Wh / kg, reduces its weight to several kilograms. However, the electrical vehicle drive (that is necessary here besides the traction motor), designed for maximum power; therefore, it is very heavy, reduces the effectiveness of this scheme. And , the electrical vehicle drive like traction motor should be reversible (both motor and generator) , which further complicates the drive .
Original scheme of hybrid powertrain with flywheel drive and electromechanical drive was offered, manufactured and tested by "BMW" (Germany). The undoubted advantage of the solution is to have only one electric machine, which reduces weight and brings it to the car scheme (see scheme). Type of flywheel designed by "BMW" does not specify in the report why the drive used is conventionally called a "flywheel".

Scheme hybrid powertrain with flywheel drive and electromechanical drive firms "BMW" (Germany)
1 - a current source, 2 - control system 3 - reversible electric machine 4 - differential mechanism 5 - multiplier 6 - flywheel storage, 7 - main gear
The current source 1 through converters and a control system 2 connected to a reversible electric machine 3 designed for the maximum electric power. Eclectic mashie 3 through a complex differential mechanism 4 with multiplier 5 connected with the flywheel 6 and main gear 7. As a result, the mass of the current source 1, for example, a fuel cell can be selected on the basis of specific energy not specific capacity that reduces it for an electric vehicle and a electric bus that has mileage, respectively , 400 and 600 km to 100 - 150 and 700 - 1000 kg. This is perfectly acceptable for these vehicles.
However, an essential drawback of all electric circuits is the presence of heavy and complex reversible electric motor. This affects the efficiency of the drive and its mass, including the current transducer. Powerful electrical machine is uneconomical when working at low power that is typicsl for the acceleration of flywheel drive.
A new concept of electric car that is proposed by professor N.V. Gulia , consists of maximal approximation and harmonization of electrical car. This allows extremely simplify and downsize the mass of powertrain of the vehicle and to increase its efficiency and effectiveness of energy recovery, as well as make it possible to use the existing chassis of cars and buses for the installation of electric powertrains and electric buses. The last condition should significantly reduce the cost of the car and unify their production to the maximum extent with the ability to quickly change the ratio of different types of cars and their software release. In addition, if the customer wants, the vehicle may be equipped with both a source of mechanical energy (conventional or hybrid heat engine) and electric (fuel cells, Flywheel energy storage), with the installation of replacement units in the same engine compartment while preserving the entire powertrain. Such transmissions are already widely used on cars companies such as Nissan, Honda, Fiat, Subaru, etc.
In conclusion, acceleration of scientific and technological progress in transport industry in modern conditions a problem that is complex and capital-intensive. Modern life is characterized by the rapid development of science and technology in all spheres of human activity. This process determines the nature of a quick change of technique and technology in all sectors of the economy, including the transport. Nowadays, technological progress is developing extremely fast. The result is rapid obsolescence of equipment; there is a need for new discoveries. New types of transport are designed to facilitate a person's life, making it more comfortable, but they are required to comply with all environmental regulations, which every year are becoming tougher. New types of transport are only a small part of all the improvements that are made by man over the past few years. Some of them are the current system, others are awaiting commissioning after reaching currently testing, and others are too futuristic and expensive to exist (but they can become a reality in the near future). But all of them today help society to solve the pressing problems that have arisen as a result of human activity, and this process cannot be stopped.

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