27-08-2012, 04:02 PM
HYBRID ELECTRIC VEHICLES
Introduction to Electric Vehicles(AF exp 8).docx (Size: 16.78 KB / Downloads: 37)
Introduction to Electric Vehicles
Environmental as well as economical issues provide a compelling impetus to
develop clean, efficient, and sustainable vehicles for urban transportation.
Automobiles constitute an integral part of our everyday life, yet the exhaust
emissions of conventional internal combustion (IC) engine vehicles are to blame
for the major source of urban pollution that causes the greenhouse effect leading
to global warming. The dependence on oil as the sole source of energy for
passenger vehicles has economical and political implications, and the crisis will
inevitably become acute as the oil reserve of the world diminishes.
Electric vehicles paved their way into public use as early as the middle of the
19th century, even before the introduction of gasoline-powered vehicles. In the
year 1900, 4200 automobiles were sold, out of which 40% were steam powered,
38% were electric powered, and 22% were gasoline powered. However, the
invention of the starter motor, improvements in mass production technology of
gas-powered vehicles, and inconvenience in battery charging led to the
disappearance of the EV in the early 1900s. However, environmental issues and
the unpleasant dependence on oil led to the resurgence of interest in EVs in the
1960s. Growth in the enabling technologies added to environmental and
economic concerns over the next several decades, increasing the demand for
investing in research and development for EVs. Interest and research in EVs
soared in the 1990s, with the major automobile manufacturers embarking on
plans for introducing their own electric or hybrid electric vehicles. The trend
increases today, with EVs serving as zero-emission vehicles, and hybrid electric
vehicles already filling in for ultralow-emission vehicles
COMPONENTS OF AN EV
The primary components of an EV system are the motor, controller, power
source, and transmission.
Electrochemical batteries have been the traditional source of energy in EVs.
Lead-acid batteries have been the primary choice, because of their welldeveloped
technology and lower cost, although promising new battery
technologies are being tested in many prototype vehicles. The batteries need a
charger to restore the stored energy level once its available energy is near
depletion due to usage. Alternative energy sources are also being developed for zero-emission vehicles. The limited range problem of battery-driven EVs
prompted the search for alternative energy sources, such as fuel cells and
flywheels. Prototypes have been developed with fuel cells, while production
vehicles will emerge in the near future.
The majority of electric vehicles developed so far are based on DC machines,
induction machines, or permanent magnet machines. The disadvantages of DC
machines pushed EV developers to look into various types of AC machines. The
maintenance-free, low-cost induction machines became an attractive alternative
to many developers. However, high-speed operation of induction machines is
only possible with a penalty in size and weight. Excellent performance together
with high-power density features of permanent magnet machines make them an
attractive solution for EV applications, although the cost of permanent magnets
can become prohibitive. High-power density and a potentially low production
cost of switched reluctance machines make them ideally suited for EV
applications. However, the acoustic noise problem has so far been a deterrent for
the use of switched reluctance machines in EVs. The electric motor design
includes not only electromagnetic aspects of the machine but also thermal and
mechanical considerations. The motor design tasks of today are supported by
finite element studies and various computer-aided design tools, making the
design process highly efficient.
RECENT EVs AND HEVs
The manufacturers of EVs in the 1990s realized that their significant research
and development efforts on ZEV technologies were hindered by unsuitable
battery technologies. A number of auto industries started developing hybrid
electric vehicles (HEVs) to overcome the battery and range problem of pure
electric vehicles. The Japanese auto industries lead this trend with Toyota,
Honda, and Nissan already marketing their Prius, Insight, and Tino model hybrids.
The hybrid vehicles use an electric motor and an internal combustion engine and,
thus, do not solve the pollution problem, although it does mitigate it. It is perceived
by many that the hybrids, with their multiple propulsion units and control
complexities, are not economically viable in the long run, although currently a
number of commercial, prototype, and experimental hybrid vehicle models are
available from almost all of the major automotive industries around the world.
Toyota, Honda, and Nissan are marketing the hybrid vehicles well below the
production cost, with significant subsidy and incentive from the government.
However, the cost of HEVs and EVs are expected to be high until production
volume increases significantly.
EV MARKET
We normally discuss the use of EVs for passenger and public transportation but
tend to forget about their use as off-road vehicles in specialty applications, where
range is not an issue. EVs have penetrated the market of off-road vehicles
successfully over the years for clean air as well as for cost advantages. Examples
of such applications are airport vehicles for passenger and ground support;
recreational vehicles as in golf carts and for theme parks, plant operation
vehicles like forklifts and loader trucks; vehicles for disabled persons; utility
vehicles for ground transportation in closed but large compounds; etc. There are
also EVs that run on tracks for material haulage in mines. There is potential for
EV use for construction vehicles. The locomotives that run on tracks with
electricity supplied from transmission lines are theoretically no different from
other EVs, the major difference being in the way energy is fed for the propulsion
motors
Introduction to Electric Vehicles(AF exp 8).docx (Size: 16.78 KB / Downloads: 37)
Introduction to Electric Vehicles
Environmental as well as economical issues provide a compelling impetus to
develop clean, efficient, and sustainable vehicles for urban transportation.
Automobiles constitute an integral part of our everyday life, yet the exhaust
emissions of conventional internal combustion (IC) engine vehicles are to blame
for the major source of urban pollution that causes the greenhouse effect leading
to global warming. The dependence on oil as the sole source of energy for
passenger vehicles has economical and political implications, and the crisis will
inevitably become acute as the oil reserve of the world diminishes.
Electric vehicles paved their way into public use as early as the middle of the
19th century, even before the introduction of gasoline-powered vehicles. In the
year 1900, 4200 automobiles were sold, out of which 40% were steam powered,
38% were electric powered, and 22% were gasoline powered. However, the
invention of the starter motor, improvements in mass production technology of
gas-powered vehicles, and inconvenience in battery charging led to the
disappearance of the EV in the early 1900s. However, environmental issues and
the unpleasant dependence on oil led to the resurgence of interest in EVs in the
1960s. Growth in the enabling technologies added to environmental and
economic concerns over the next several decades, increasing the demand for
investing in research and development for EVs. Interest and research in EVs
soared in the 1990s, with the major automobile manufacturers embarking on
plans for introducing their own electric or hybrid electric vehicles. The trend
increases today, with EVs serving as zero-emission vehicles, and hybrid electric
vehicles already filling in for ultralow-emission vehicles
COMPONENTS OF AN EV
The primary components of an EV system are the motor, controller, power
source, and transmission.
Electrochemical batteries have been the traditional source of energy in EVs.
Lead-acid batteries have been the primary choice, because of their welldeveloped
technology and lower cost, although promising new battery
technologies are being tested in many prototype vehicles. The batteries need a
charger to restore the stored energy level once its available energy is near
depletion due to usage. Alternative energy sources are also being developed for zero-emission vehicles. The limited range problem of battery-driven EVs
prompted the search for alternative energy sources, such as fuel cells and
flywheels. Prototypes have been developed with fuel cells, while production
vehicles will emerge in the near future.
The majority of electric vehicles developed so far are based on DC machines,
induction machines, or permanent magnet machines. The disadvantages of DC
machines pushed EV developers to look into various types of AC machines. The
maintenance-free, low-cost induction machines became an attractive alternative
to many developers. However, high-speed operation of induction machines is
only possible with a penalty in size and weight. Excellent performance together
with high-power density features of permanent magnet machines make them an
attractive solution for EV applications, although the cost of permanent magnets
can become prohibitive. High-power density and a potentially low production
cost of switched reluctance machines make them ideally suited for EV
applications. However, the acoustic noise problem has so far been a deterrent for
the use of switched reluctance machines in EVs. The electric motor design
includes not only electromagnetic aspects of the machine but also thermal and
mechanical considerations. The motor design tasks of today are supported by
finite element studies and various computer-aided design tools, making the
design process highly efficient.
RECENT EVs AND HEVs
The manufacturers of EVs in the 1990s realized that their significant research
and development efforts on ZEV technologies were hindered by unsuitable
battery technologies. A number of auto industries started developing hybrid
electric vehicles (HEVs) to overcome the battery and range problem of pure
electric vehicles. The Japanese auto industries lead this trend with Toyota,
Honda, and Nissan already marketing their Prius, Insight, and Tino model hybrids.
The hybrid vehicles use an electric motor and an internal combustion engine and,
thus, do not solve the pollution problem, although it does mitigate it. It is perceived
by many that the hybrids, with their multiple propulsion units and control
complexities, are not economically viable in the long run, although currently a
number of commercial, prototype, and experimental hybrid vehicle models are
available from almost all of the major automotive industries around the world.
Toyota, Honda, and Nissan are marketing the hybrid vehicles well below the
production cost, with significant subsidy and incentive from the government.
However, the cost of HEVs and EVs are expected to be high until production
volume increases significantly.
EV MARKET
We normally discuss the use of EVs for passenger and public transportation but
tend to forget about their use as off-road vehicles in specialty applications, where
range is not an issue. EVs have penetrated the market of off-road vehicles
successfully over the years for clean air as well as for cost advantages. Examples
of such applications are airport vehicles for passenger and ground support;
recreational vehicles as in golf carts and for theme parks, plant operation
vehicles like forklifts and loader trucks; vehicles for disabled persons; utility
vehicles for ground transportation in closed but large compounds; etc. There are
also EVs that run on tracks for material haulage in mines. There is potential for
EV use for construction vehicles. The locomotives that run on tracks with
electricity supplied from transmission lines are theoretically no different from
other EVs, the major difference being in the way energy is fed for the propulsion
motors