Session B5
Paper #2189
REGENERATIVE BRAKING: STOPPING DOESN’T HAVE TO SLOW YOU
DOWN
Spencer Evans (sye1@pitt.edu), Matt Hilger (mjh114@pitt.edu)
Abstract— This paper will explore and assess the
technology and benefits of regenerative braking in electric
and hybrid cars. Regenerative braking is a technology that
recovers and harnesses some of the energy lost to friction
during braking and converts it to electrical energy to be
used to charge the car’s batteries. Shifting our focus from
traditional vehicles to hybrid and electric vehicles would
alleviate much of our dependence on fossil fuels, and aid in
the restoration of the environment. Regenerative braking is a
key feature of hybrid and electric cars: one that will make
the transition to zero-emission vehicles more appealing,
cost-effective and environmentally beneficial. Our paper will
explore the process and mechanics by which regenerative
braking works. We will then discuss examples of how
regenerative braking is currently being used to demonstrate
its improvement over traditional braking. We will also
discuss some of the limitations of regenerative braking.
Throughout, our paper will focus on the economic and
environmental benefits of regenerative braking, and
demonstrate its potential as a long-term energy saving
solution.
newly introduced fully electric vehicles that produce zero
emissions of carbon dioxide, and are an environmentally
cleaner option than even hybrid vehicles. Although fully
electric vehicles have the possibility of being a future longterm solution to eliminate carbon emissions from our
vehicles, they still possess some limitations, such as their
limited range and expensiveness. A necessary goal for
mechanical engineers should be to improve these electric
vehicles to the point where they perform equally to
traditional automobiles and also produce zero harmful
emissions. An important feature of hybrid and electric
vehicles that is helping to achieve this goal and makes these
vehicles such an improvement over traditional automobiles
is regenerative braking. Regenerative braking harnesses
energy that is normally lost to heat during braking, and
converts it to electrical energy to recharge the car’s battery
and improve overall efficiency.
THE MECHANICS EXPLAINED
Regenerative braking is by no means a simple process. For a
hybrid vehicle, the basic theory is as such: the internal
combustion engine produces chemical energy from the fuel,
a generator then acts to use this chemical energy to produce
electrical energy that the electric traction motor drive will
use to provide a torque to the wheels, propelling the vehicle
forward. When the vehicle brakes, the opposite occurs and
the wheels provide a negative torque to the electric traction
motor, which causes the motor to run in reverse enabling it
to act as a generator and produce energy that is then utilized
to charge the car’s battery [3]. There are certain problems
that arise when considering this basic theory that must be
taken into consideration. For example, what can be done to
prevent wasting of this recovered energy when the car’s
batteries are fully charged? This recovered energy cannot be
continuously pumped into a fully charged battery due to a
high possibility of overheating. Therefore, the regenerative
braking system must either be disconnected when the battery
is fully charged, or preferably, the recovered energy has to
be stored in a manner that would allow it to be later accessed
to charge the battery once the charge on the battery began to
deplete. U.S. patent no. 5,291,960 by Larry Brandenburg
and Edward King introduces the first regenerative braking
system that utilizes the energy generated during braking to
recharge the main storage battery and also store the excess
energy [4]. They also described other innovative ways to use
this captured energy, for example, to preheat the internal
combustion engine to reduce the extra carbon emissions
produced from driving with a cold engine [4]. Still, the most
important aspect of a regenerative braking system is the
Key Words – Energy, Fuel Economy, Nissan, Regenerative
braking, Tesla
INTRODUCTION TO REGENERATIVE BRAKING
“There can be no doubt about the scale of the global
challenge we face, to address the issue of man-made climate
change, and in particular, the role which transport plays
within that” [1]. The increasing amount of carbon dioxide
emissions filling our atmosphere has exponentially increased
since the introduction of vehicles onto our highways. As the
carbon dioxide levels accumulate, our planet’s protective
ozone layer slowly diminishes, leaving Earth exposed to
harmful ultraviolet rays and increasing the prospect of global
warming that many experts have come to fear. With the
carbon dioxide emissions from vehicles being a prominent
cause of global warming, it is imperative that we find ways
to improve the fuel efficiency and reduce the harmful
environmental consequences of our vehicles. One measure
that we can and should take is to shift from traditional
vehicles to hybrid and electric vehicles.
With much improved fuel efficiency, hybrid vehicles
have proven to be a viable solution to greatly reducing the
amount of carbon dioxide that a vehicle emits. Their mile
per gallon range greatly exceeds standard automobiles,
preventing each car from releasing approximately 9
kilograms of carbon dioxide into the atmosphere with every
gallon of gasoline burned [2]. An even better solution is
University of Pittsburgh
Swanson School of Engineering
April 14, 2012
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Matt Hilger
component that generates the electrical energy that will be
utilized to perform these functions. This component is the
electric traction motor drive.
Electric Traction Motor Drive
The electric traction motor drive is the integral component in
determining the efficiency of a regenerative braking system,
as it is the part of the system that actually recovers the
energy from braking. But, as the electric motor of the
vehicle, it also provides the power in the form of electrical
energy to the vehicle’s wheels, generating torque, and
allowing the vehicle to propel forward [5]. When looking at
the history of electric traction motor drives, they are
certainly not a new technology. They have been commonly
used in electric trains and subways for many years. The
motor drives in these situations though, require a large
amount of power and generally have a constant supply of
power through the use of overhead railway lines [6]. But for
a typical vehicle, the battery, a source that can only provide
a limited amount of power, supplies the power, which
creates some difficulties in the design of this traction motor
to optimize performance.
When considering the electric traction motor drive in a
hybrid or electric vehicle, many considerations must be
taken into account to maximize the motor’s efficiency. In
the propulsion of hybrid and electric vehicles, it is expected
that the traction motor be utilized throughout the entire range
of velocities and torques that the vehicle can achieve. Thus,
the motor must be able to handle relatively frequent starting
and stopping and rapid acceleration rates, which requires the
motor to be able to produce a large amount of torque at all
speeds [5]. High torque density, or the ratio of the torque
produced by the motor to the mass of the motor system, is
greatly desired [5]. A lightweight electric traction motor
with a high torque output will certainly help maximize a
motor’s efficiency. Other attributes such as controllability
and stability are required for a successful electric traction
motor, and thus, the motor must be tested at all possible
combinations of torques and velocities that the motor is
capable of [5].
A widely accepted and convenient method of describing
the efficiency of electric traction motor drives is by an
efficiency map. An efficiency map plots the motor speed
versus the torque supplied by the motor and provides an
efficiency rating at these points [5]. Efficiency maps prove
to be extremely useful in that they allow engineers to
analyze the efficiency of these traction motors at all ranges
of speed and torque that can be supplied by the motor. A
typical efficiency map for an electric traction motor is
displayed in figure 1.
FIGURE 1
TYPICAL EFFICIENCY MAP OF A TRACTION MOTOR FOR A HYBRID VEHICLE
[5]
In a comprehensive study of the efficiency of electric
traction motor drives in hybrid vehicles performed by the
Institute of Electrical and Electronics Engineers, the
efficiency of a 45 kW traction motor in a hybrid vehicle was
determined to be approximately 90% for both city and
highway driving, an impressive efficiency rating [5]. The
efficiency that the electric traction motor provides is
immensely important in the process of regenerative braking.
When the brakes are pressed, the traction motor reverses its
direction and acts as a generator, producing usable energy,
instead of using the supplied energy to propel the vehicle
when the motor is running in the forward direction. The high
efficiency discovered in this study would allow for the
prospect of a large amount of energy typically lost to
braking to be recovered by the traction motor drive and
utilized for other purposes [5]. The ensuing section will
completely describe the process that makes use of this
recovered energy.
Utilizing Recovered Energy
Larry R. Brandenburg and Edward T. King provided the
schematic below in the patent of their efficient regenerative
braking system. It depicts a hybrid vehicle that features an
electrical traction motor that provides the torque to drive the
vehicle’s wheels, and an independent internal combustion
engine. The traction motor would be electrically supplied
either by a fairly typical storage battery, a generator powered
by the internal combustion engine, or a combination of
battery and generator [4]. Since the internal combustion
engine runs independently of the traction motor, the engine
could be shut down for much of the time, to minimize
emissions. It also becomes preferred to preheat the engine
before start up, since it has been determined that
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approximately 80% of the emissions from a typical vehicle
are created during the ignition and initial driving of a cold
engine [4]. A goal in regenerative braking systems is to use
some of the recovered energy to warm the engine before
ignition, greatly reducing carbon emissions.
store any excess energy waste produced during the
regenerative braking cycle.
To be able to store and use the electrical energy produced
through regenerative braking, a resistive heater must be
included in the schematics. Located on the conduit
connecting the heat battery back to the engine, the resistive
heater will first use its generated heat to warm the internal
combustion engine before start up [4]. At the same time, the
resistive heater could supply the passenger compartment of
the vehicle with heat whenever a passenger demands it. If it
is determined that the engine has already been warmed to an
acceptable initial temperature, the storage battery is fully
charged, and the passenger is not demanding heat, the
resistive heater will simply deposit its excess energy safely
into the heat battery [4].
On initial start up of the vehicle, the following process
occurs. The system controller detects the charge of the
storage battery. If the charge is sensed to be full, the system
controller will send a signal to the switch mechanism to
block the current being provided by the generator from
reaching the battery, and instead use this power to supply the
traction motor [4]. If the system controller detects the
storage battery to be in a low state of charge, it will signal
the switch mechanism to allow the necessary current through
to the battery, until the desired charge has been acquired [4].
While the car is driving, the traction motor is being
supplied with electrical energy from the storage battery. But,
when the driver takes his foot off of the accelerator and
begins coasting, the process of regenerative braking begins.
The traction motor converts into a generator and also slows
the vehicle wheels. A signal from the traction motor to the
system controller causes the controller to activate the switch
mechanism [4]. If the storage battery is not fully charged,
the regenerative energy will flow through the switch
mechanism to the battery. If the system controller detects the
battery to be fully charged, the switch mechanism is signaled
to deliver this energy to the resistive heater to be stored for
other uses [4].
When the internal combustion engine is not running and
its temperature is sensed by a temperature sensor attached to
the engine to be lower than the desired value for initial
startup, heat stored in the resistive heater will circulate
through a conduit connecting the heater and the internal
combustion engine [4]. This energy will preheat the internal
combustion engine, preventing cold engine driving from
producing large amounts of emissions.
The process of regenerative braking is a complicated
process dependent on the correct placement, operation, and
integration of several key electrical and mechanical
components. The traction motor, battery, engine generator,
and resistive heater must all be designed correctly to allow
for regenerative energy production and storage. These
components must also be fully in sync with the system
controller that signals the switch mechanism to redirect the
recovered energy to the areas of the vehicle that are in need
of the recovered energy. This process of regenerative
FIGURE 2
REGENERATIVE BRAKING SCHEMATIC [4]
The internal combustion engine is central in a closed loop
circuit that allows for standard cooling procedures to prevent
overheating [4]. Another circuit runs from the internal
combustion engine to the passenger compartment heater,
providing heat to the passengers of the car. The conduits
continue to run from the passenger compartment heater to
the heat battery, an important aspect of regenerative braking.
The heat battery exists to store excess heat that is not
immediately used to charge any part of the vehicle. A heat
battery may use salt mixtures, which become melted when
excess heat is transferred to the battery [4]. The changing of
phases of the salt mixtures releases a large amount of
energy, which allows the heat battery to have such a high
capacity of storage. The heat battery allows for a safe way to
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braking is also more than just a theory with accompanying
schematic drawings; it has been successfully tested and
developed, as the proceeding section will discuss.
SUCCESSFUL TESTING AND DEVELOPMENT
Regenerative braking is a technology that has been
extensively tested and developed. In all of the testing that
regenerative braking has undergone, it has proven to be a
very successful technology for improving fuel efficiency and
reducing carbon emissions. There are two important
examples of testing and development of regenerative braking
that we will discuss in detail. The first set of testing was
performed at the Transport Research Institute at the
Edinburgh Napier University in which regenerative braking
was implemented into two very different vehicles and then
extensively tested. In a second set of research, regenerative
braking was integrated with antilock brakes into a single
system allowing regenerative braking to be a more readily
usable technology.
FIGURE 3
INCREASE IN FUEL EFFICIENCY VS. ULTRACAPACITOR CAPACITY FOR
ŠKODA FABIA [7]
These results show significant and important findings for
regenerative braking. The testing of the Škoda Fabia
provides very distinct evidence that regenerative braking can
greatly improve the fuel efficiency of an automobile.
Furthermore, the results show that regenerative braking can
be implemented into typical, commercialized vehicles such
as the Škoda Fabia with impressive results, proving that
regenerative braking is a technology that can have an
immediate beneficial impact if implemented into a greater
number of cars in the near future.
Also, the effects of energy storage capability on
efficiency were also tested. It was found that the optimum
regenerative energy storage capacity for this vehicle is 15Watt hours (Wh). Energy capacity beyond 15 Wh
significantly increases the cost and mass of the regenerative
braking system for an insignificant increase in efficiency [7].
A Regenerative braking system integrated with an
ultracapacitor will maximize the fuel efficiency output of the
braking system.
Possibly the most important finding of the testing of the
Škoda Fabia is the reduction of carbon dioxide emissions.
After the regenerative braking system had been implemented
into the vehicle, the carbon dioxide emissions during an
urban driving test were just 67 g/km, a 52% decrease from
the vehicles initial emissions without regenerative braking
[7]. This reduction in carbon emissions helps to explain how
regenerative braking is an important technology in reducing
our population’s recent negative impacts on the
environment.
The Transport Research Institute
In the research done at the Transport Research Institute at
the Edinburgh Napier University, regenerative braking was
implemented into two very different vehicles, and energy
efficiency and emissions were tested extensively [7].
Furthermore, the potential of using ultracapacitors as energy
storage devices as opposed to typical automobile batteries
was also explored. Ultracapacitors have higher power
densities, as well as charge and discharge capabilities, than
traditional batteries, better allowing regenerative braking to
yield its maximum efficiency increase [7]. The vehicles
tested were the Škoda Fabia compact car and the EVT
4000E electric scooter.
Škoda Fabia
The Škoda Fabia is a rather typical small automobile that
does not have regenerative braking capabilities. This car was
then outfitted with a regenerative braking system coupled
with an ultracapacitor and was tested in both city and rural
environments to determine the effect of regenerative braking
on the vehicle’s fuel efficiency and carbon emissions. The
Škoda Fabia initially consumed 5.24 Liters per kilometer
(L/km) and emitted 140 grams of fuel for every kilometer
traveled (g/km). In the city model, a 54% increase in fuel
efficiency was achieved by the implementation of
regenerative braking; in the rural model, a 29% increase in
fuel efficiency was found, as described in Figure 3 shown
below [7].
EVT 4000E Electric Scooter
Although the EVT 4000E electric scooter does not produce
any carbon emissions, incorporating a regenerative braking
system into its existing electrical drive could still prove
beneficial. Increased range would allow the electric scooter
to become a more appealing option for city residents who
have a short commute to work everyday, thus completely
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eliminating carbon emissions from people who decide to use
an electric scooter as transport.
When the EVT 4000E electric scooter was outfitted with
a regenerative braking system and an ultracapacitor, the
scooter’s range per charge efficiency significantly increased.
An 18% increase in the electric scooter’s range per charge
can be seen in Figure 4 shown below, with an optimum
energy capacity of just 1 Wh [7]. This small optimal energy
capacity of the ultracapacitor in the electric scooter also
minimizes the weight of the regenerative braking system to
just 1 kg, and therefore also helps reduce the cost of the
whole system [7].
INTEGRATION WITH ANTILOCK BRAKES
One paper from the International Journal of Automotive
Technology describes a system that integrates regenerative
braking and antilock brakes into a single braking system. In
such a system, hydraulic brakes take over in situations where
regenerative braking either cannot provide sufficient torque
on its own, or cannot function due to conditions such as a
high state of charge (SOC) or a high temperature in the
battery. The system utilizes both a logic threshold control
strategy and a fuzzy logic control strategy. The logic
threshold control strategy adjusts the hydraulic braking
torque as needed. The fuzzy logic control strategy is based
on the slip ratio, which is the ratio of the speed of the wheels
of a vehicle to the speed of the vehicle itself. This control
strategy allows for dynamic adjustment to the regenerative
braking torque [8]. A simulation was used to verify the
stability and effectiveness of the integrated braking system.
The simulation tested the efficiency of the braking system
under two sets of conditions: standard conditions, as per the
New European Driving Cycle (NEDC), and slick conditions
that demand performance from the antilock brake part of the
integrated system.
For the tests run under the NEDC, only moderate braking
was required, so the regenerative brakes were the main
source of braking in the system. This allowed for the
production of considerable amounts of regenerative energy.
The statistics of the NEDC test are detailed in Figure 5
below [8].
FIGURE 4
INCREASE IN FUEL EFFICIENCY VS. ULTRACAPACITOR CAPACITY FOR EVT
4000E SCOOTER [7]
When comparing results of the EVT 4000E electric
scooter to the Škoda Fabia many correlations can be drawn.
The first and most important one being that regenerative
braking is a successful technology that will do much to help
us reduce the harmful carbon emissions we continue to
release into our air. The increase in efficiency that
regenerative braking provides to these vehicles is quite
remarkable and allows them to be improved options over
traditional automobiles.
One aspect that does arise though when discussing
regenerative braking is the cost, which will be discussed in
more detail later. A regenerative braking and ultracapacitor
system is a fairly expensive system to incorporate into a
vehicle. This limitation could allow electric scooters or other
similar means of transport to become a popular and
affordable option, due to the smaller size of the
ultracapacitor and braking system in general. Current uses of
regenerative braking in hybrid and electric vehicles have
been very successful, but are still an expensive option. This
should spark consideration for the possibility of mass
marketing of electric scooters or bikes employing
regenerative braking as an affordable, environmentally
friendly option that greatly utilizes the efficiency of
regenerative braking.
FIGURE 5
REGENERATIVE ENERGY OVER TIME FOR NEDC DRIVING STANDARD [7]
The brakes also performed well under the emergency
braking demand conditions. In a deceleration from 90-0
km/h on a low adhesion coefficient road, the wheels never
lock. Furthermore, the regenerative brakes and hydraulic
brakes cooperated well, and the regenerative brakes still
managed to yield 9.029% regenerative energy [8]. The
statistics of the emergency demand-braking test are detailed
in Figure 6 below.
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spoken about the constraints and limitations that must be
considered when designing and deploying a regenerative
braking system. Some limitations are inevitable results of the
nature of regenerative braking. For example, even though
the conversion of electrical potential energy to kinetic
energy in the wheels measures around 80%, kinetic energy
must be converted back to electrical potential energy at the
same efficiency, so the energy retention given a 80%
conversion rate is 80% * 80% = 64%. At best, we can hope
to minimize energy dissipation to increase conversion
efficiency [10].
Other limitations restrict when regenerative braking can
be used. Safety becomes a concern under more extreme
braking conditions, where the negative torque imparted by
the regenerative brakes can cause the car to be unstable. To
ensure stability, regen is limited if the wheels start to slip.
Additionally, energy regeneration must be limited when the
battery is fully charged to prevent potential from rising to
dangerous levels [10].
Despite these limitations, however, the Tesla Roadster
has managed to make excellent use of regenerative braking.
This is not only apparent in the energy efficiency of the car,
but also the car’s low CO2 emissions. It is an incomplete
assessment to say that because the car is purely electric, it
gives no emissions. While this is technically true, it doesn’t
consider the indirect emissions from the energy generation
process. With these indirect emissions in mind, it is apparent
that how much electric vehicles cut emissions depends on
how clean the energy generation process is. For countries
like the U.S. and U.K., the well-to-wheels CO2 emissions
decrease is actually relatively small, especially when
compared to the decrease in a country like France, where
electricity is primarily generated by nuclear power [11]. The
comparisons of well-to-wheels CO2 emissions in these three
countries for the Tesla Roadster and two other electric
vehicles, the REVAi and the TH!NK City, are shown in
figure 7 below.
FIGURE 6
ENERGY REGENERATION UNDER EMERGENCY BRAKING CONDITIONS [8]
After simulation, the combined braking system was
installed in an EQ7200HEV chassis and given field runs.
The results of the field tests were consistent with the
simulations. The combination of regenerative braking and
electric braking makes for a braking system that both
regenerates energy efficiently and performs well under
emergency conditions. This research proves that
regenerative braking is a technology that, when
implemented, yields benefits to fuel efficiency without
sacrificing any performance [8].
REGENERATIVE BRAKING IN THE REAL WORLD
While regenerative braking systems have tested superbly
under different conditions, with all tests providing excellent
increases in energy efficiency and reduction of carbon
emissions, regenerative braking systems have also proven to
be just as effective in commercialized vehicles. All popular
hybrid vehicles utilize regenerative braking to acquire
maximum efficiency from their engines. At this point in our
paper, we will show how regenerative braking has proven to
be a successful real world application that is currently being
applied to hybrid and electric vehicles. In particular, we will
take a look at the Tesla Roadster to demonstrate how fuel
efficient and environmentally low-impact cars that use
regenerative braking can be.
The Tesla Roadster
Tesla has put out a truly impressive product in their Roadster
sport car. The Roadster is still a powerful car, despite being
fully electric. It is capable of reaching a top speed of 125
mph, and has a 0 to 60 mph acceleration time of 3.7 seconds.
More importantly, the Roadster has a range of 245 miles per
charge. This is in part thanks to the high energy density of
Tesla’s Lithium-ion batteries, but the mileage is also
increased by the energy conserved by regenerative braking
[9].
Tesla is still working to improve their implementation of
regenerative braking. Firmware engineer Greg Solberg has
FIGURE 7
WELL-TO-WHEELS CO2 EMISSIONS FOR THE TESLA ROADSTER, TH!NK
CITY, AND REVAI [11]
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Even so, the decrease in CO2 emissions when using an
electric vehicle when compared to a traditional combustion
engine vehicle is very tangible, even in the US and UK. In a
hypothetical situation where the fleet of all passenger cars in
each country is replaced with a fleet of electric vehicles such
as the Tesla Roadster, the decrease in CO2 emissions is
extremely significant. The comparisons of current and
hypothetical EV fleets are shown below.
outfitted with regenerative braking capabilities will save six
metric tonnes of carbon dioxide from damaging our
atmosphere in the vehicle’s lifespan [7]. It becomes obvious
that if regenerative braking were added to a greater number
of vehicles, the environmental benefits would be much more
noticeably impressive.
TABLE 1
Regenerative braking is a technology that provides many
benefits but also has some slight limitations that should be
discussed. The first limitation is the cost. It costs
approximately $3000 to put a regenerative braking system
on a vehicle, which is a fairly hefty price tag [7]. But, the
savings that regenerative braking provides in fuel efficiency
will likely cover the cost of the system within a few years.
Also, as shown in Table 2 below, regenerative braking
decently reduces the amount of power required by the
engine. With the engine consistently experiencing less stress,
the possibility of the engine breaking down reduces, saving a
large sum of money.
TABLE 2
Possible Limitations
COMPARISON OF CURRENT FLEET TO PURELY ELECTRIC FLEET [11]
Even though the benefits of using cars such as the Tesla
Roadster are hindered by the indirect emissions due to the
electricity generation process, they are still significant. Tesla
is an excellent indicator of how fuel efficient and lowemission our fleet can be if electric vehicles become more
commonplace.
POWER OUTPUT OF ENGINE WITH AND WITHOUT REGENERATIVE BRAKING
[7]
OVERALL BENEFITS OF REGENERATIVE
BRAKING
As previously discussed in the testing and development
section, regenerative braking has wide ranging benefits that
go even beyond improved fuel efficiency and reduced
carbon emissions. But these two benefits are the most
important and have the potential to have the most positive
influential impacts and deserve more detailed discussion.
A regenerative braking system employed into a Škoda
Fabia compact car improved fuel efficiency in both city and
rural driving by 54% and 29% respectively. When a
regenerative braking system was employed into an EVT
4000E electric scooter, an 18% increase in range per charge
was experienced [7]. These large increases in efficiency
should provide drivers a sense of relief. With fuel prices
being higher than they have ever been, any increase in fuel
efficiency, especially the large increases provided by
regenerative braking, becomes monumentally important. The
addition of a regenerative braking system also significantly
reduced carbon emissions of the Škoda Fabia as previously
discussed. The environmental issues currently facing our
planet have only worsened in recent years and discovering a
solution is imperative. Although regenerative braking will
not completely mend the damaged environment and
atmosphere, it can certainly provide a lot of help. Based on
the fuel efficiency increases and carbon emission reductions
discovered in this study, it is estimated that a vehicle
Regenerative braking is also typically limited by the
efficiency of the electric traction motor drive and the
capacity to store this energy. But as discussed earlier,
traction motors have proven to be very efficient and with a
correctly designed resistive heater and heat battery, storage
of energy will not be a problem. A final limitation of
regenerative braking is that it still relies on mechanical
braking for rapid deceleration and when the regenerative
braking system fails. But also discussed earlier was the
integration of antilock brakes with regenerative braking.
Even under emergency stopping conditions, the regenerative
brakes still recovered some usable energy while proving to
be completely safe.
FINAL ANALYSIS OF REGENERATIVE BRAKING
Regenerative braking has proven to be a successful
technology through testing and deployment into modern
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Energies. http://www.mdpi.com/1996-1073/4/9/1461/#cite. Accessed: 26
January 2012.
hybrid and electric vehicles. It effectively reduces carbon
emissions and increases fuel efficiency. Given the present
environmental issues facing our world, it is vital that we
implement measures such as implementing regenerative
braking that so effectively reduce our dependence on
nonrenewable resources and the negative environmental
impacts of our automotive fleet. As previously discussed in
our analysis of the Tesla Roadster, additional measures such
as the switch to nuclear energy would allow regenerative
braking to have a tremendous positive impact on our
environment. As we proceed towards a greener future,
regenerative braking has already proven to be an effective
and efficient technology that will only improve as other
measures continue to be implemented.
ACKNOWLEDGEMENTS
We would like to thank our co-chair Pramod Jacob for
providing helpful advice to improve our paper. We would
also like to thank our session Chair Scott Meyers for guiding
us in the writing of our paper. We would also like to thank
our writing instructor Diane Kerr for her feedback on
revising our abstract. Finally, we would like to thank Kyle
Wolfe for providing inspiration as we chose our topic.
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