3. Textbooks and References
Tom denton. “ Electric and Hybrid Vehicles” Routledge Publications, 2016
Austin Hughes and Bill Drury. “ Electric Motors and Drives – Fundamentals, Types and
Applications, Newnes-Elsevier, 2013.
Vinodh kumar, Ranjan Kumar Behera, Dheeraj Joshi “ Power Electronics, Drives and Advanced
Applications”, CR press, 2020.
Gianfranco Pistoia. “Electric And Hybrid Vehicles Power Sources, Models, Sustainability,
Infrastructure and The Market”. Elsevier, 2010.
Jack Erjavec. “Hybrid, Electric & Fuel-Cell Vehicles”. Cenage Learning, 2013.
Chau. K. T. “Electric Vehicle Machines and Drives – Design, Analysis and Application”, John Wiley
& Sons Singapore Pte. Ltd., 2015
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Introduction – Why Electric and Hybrid Vehicles?
In 2022, 85.4 million motor vehicles
were produced around the world, an
increase of 5.7% compared to 2021.
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India's roadmap for electric vehicle:
Opportunities and obstacles
Challenges:
1.) Range anxiety - Range anxiety is one of the
crucial challenges ahead of the growth path for
electric vehicles in India. The EV customers are
often worried about the vehicles capability to
reach point B from point A before the battery runs
out. This issue is closely connected to the scarce
charging infrastructure in India. The Ev charging
infrastructure in India too low compared to the
petrol pumps. Also, the available Ev charging
stations are concentrated in urban areas only.
2.) Consumer perception - The consumer perception
about electric vehicles in India is still weak compared to
ICE vehicles. The range anxiety, lack of charging
infrastructure, a wide gap between EV and ICE vehicle
prices, lack of assurance about satisfactory resale value
play key roles in that. Despite the Indian consumers are
becoming more open about adopting e-mobility than
before the negative perception about EVs is still there.
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3.) High price - There is no price parity between electric
vehicles and ICE vehicles in India. Electric vehicles are
way more expensive than their conventional fuel-powered
counterparts. For example, the Tata Nexon price starts
from ₹7.19 lakh, while the Tata Nexon EV price starts
from ₹13.99 lakh. This huge price difference discourages
many interested EV buyers to shy away from making the
final decision to buy a BEV. 4.) Scarce battery technology - The lithium-ion battery is
the most popular and widely used energy source for EVs.
India doesn't produce lithium. The country doesn't
produce li-ion batteries either. India relies on import for EV
batteries resulting in the sky-high price for these important
components and eventually the EVs as well.
5.) Majority of EVs are not covered under FAME
scheme - The Indian government took an attempt to
promote electric mobility in the country via
incentivising and discounts for EVs. The terms and
conditions of the FAME scheme doesn't support a
majority of the electric vehicles. The low-speed electric
two-wheelers, lead-acid battery powered EVs are not
covered under FAME. The highly expensive high-
speed EVs on the other hand require registration
charge, driving licence. This results in many
customers shying away from buying EVs.
6.) Lack of products - There are hundreds of options of
one wants to buy a conventional fuel powered car or two-
wheeler. The case is completely different in EV segment.
Only a few options are there and majority among them are
not from established trustworthy brands. This drives the
customers away from buying EVs.
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Advantages:
1.) Low cost of ownership - It is a proven fact by many
researches that EVs offer way lower cost of ownership in
their lifecycle compared to fossil fuel powered vehicles. At
times, the cost of ownership for an EV is as lower as 27%
than a fossil fuel vehicle. The incessant rise of petrol and
diesel costs are increasing the cost of ownership further
for the conventional vehicles. 2.) Easier to maintenance - An internal combustion
engine usually contains more than 2,000 moving parts. An
electric motor onboard an EV on the other hand contain
around 20 moving parts. The only major components in an
EV are the battery and the electric motor. This makes the
EVs much easier for maintenance, reducing the cost of
ownership significantly.
3.) State EV policies - Several state governments
across India have already announced their respective
EV policies. Some of them promote the supply side,
while some promote the demand side. There are EV
policies that promote both the supply and demand side
through incentives, discounts and other benefits. Delhi
Ev policy for example is one such state EV policy.
These policies are driving the growth of the electric
vehicles in India, in a slow but steady manner.
4.) Cleaner environment - The direct and obvious
advantage of adopting electric mobility is the cleaner
environment. Electric vehicles don't emit pollutants into the
air like their ICE counterparts. The EVs are silent as well
unlike their ICE counterparts. This means EVs ensure a
cleaner and quieter environment.
51. Hybrid Electric Vehicles (HEV)
What is HEV?
As proposed by Technical
Committee 69 (Electric Road
Vehicles) of the International
Electrotechnical Commission, a
HEV is a vehicle in which
propulsion energy is available
from two or more kinds or types
of energy stores, sources or
converters, and at least one of
them can deliver electrical
energy.
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52. Classification of Hybrid Electric Vehicle
Series hybrid
Parallel hybrid
Series-parallel hybrid and
Complex hybrid.
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Power Flow Control in Series Hybrid
Mode 1, normal driving or
acceleration
Mode 2, light load
Mode 3, braking or deceleration
Mode 4, vehicle at stop
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Mode 1, start up Mode 2, acceleration Mode 3, normal drive
Mode 4, braking or deceleration Mode 5, battery charging during driving Mode 6, battery charging during standstill
The various operating modes of ICE dominated system
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The operating modes of EM dominated system
Mode 1, start up Mode 2, acceleration Mode 3, normal drive
Mode 4, braking or deceleration
Mode 5, battery charging during
driving
Mode 6, battery charging during standstill
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Condition 1- Vehicle is Stationary and engine is on idle.
1.The car always starts with the electric motor powering the
wheels.
2.But the engine is allowed to idle and run the generator
which charges the batteries and warms the engine before
both of them are put in to action.
3.For the vehicle to move the Ring Gear must move.
Condition 2- Vehicle is Moving forward:
1.The Electric Motor Drive provides power to the driving wheels.
2.Notice that the outer Ring Gear is rotating which proves that
power is being transmitted to the wheels.
3.The planetary gear carrier which is connected to the ICE is not
moving.
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Condition 3: Acceleration Above 60kmph
1.The car accelerates and needs more power.
2.The ECU acknowledges this need for extra
power. It starts the generator which in turn starts
the engine.
3.The Engine provides driving power to the
wheels.
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Tokyo―TOYOTA MOTOR CORPORATION
(TMC), riding on the success of its hot-
selling hybrid Prius sedan, leaped two
more steps ahead of the competition
today when it unveiled its new minivan-
minded Toyota Hybrid System-CVT (THS-
C) and the world's first hybrid 4-wheel-
drive powertrain, the "E-Four."
https://global.toyota/en/detail/8097499
Toyota Introduces New Hybrid System
New Technology Leads to World's First 4WD
Hybrid Powertrain
71. Mild Hybrids
A hybrid electric vehicle can perform at least one or more of the following functions:
• engine idle stop/start
• electric torque assistance (fill and boost)
• energy recuperation (regenerative braking)
• electric driving
• battery charging (during driving)
• battery charging (from the grid)
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72. Idle stop/start function
When the vehicle is stationary, the stop/start (S&S) function switches off the internal combustion engine, without
the intervention of the driver (through the ignition key).
This function reduces the overall fuel consumption of the vehicle. When the driver shows the intention to drive
(clutch pedal pressed or brake pedal released) the engine is restarted automatically.
Most of the vehicles with idle stop/start function have also some sort of energy management function, which
optimizes the consumption of the low voltage (12 V) battery energy.
In a conventional ICE vehicle, without any energy management, the primary function of the low voltage battery is
to generate the electrical energy required for the engine to start.
After the engine is running, the electrical energy for all the electrical consumers is supplied by the alternator
(generator), which is putting a load torque on the engine.
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If the vehicle has an energy management function, even if the engine is running, the battery
supplies electrical energy to the consumers.
In this way, the alternator doesn’t have to produce electrical energy, the load torque of the alternator
is nearly zero, and the fuel consumption is reduces.
Further, the battery is recharged when the engine is working in the most fuel efficient points or
when the vehicle is braking (through energy recuperation).
Renault 1.6 dCi engine (Micro Hybrid)
It comes with an Energy Smart Management
(ESM) function which allows energy created
under braking and deceleration to be stored in
the low voltage battery, helping to further
reduce fuel consumption.
75. Mahindra Micro Hybrid
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Vehicles that have idle stop/start and energy management functions
are called Micro Hybrids.
Scorpio Micro Hybrid version which comes equipped with
a start-stop system. This system can detect when the
engine is idling in neutral gear and would automatically
turn off the engine after 2-3 seconds. To start the engine
again, all that the driver has to do is engage the clutch
pedal.
76. Mild Hybrid - Electric torque assistance
The electric motor can provide additional torque to the wheel, improving the overall torque response of the
powertrain. There are two types of torque assistance:
• torque fill
• torque boost
When the drive is pressing the accelerator pedal, it requests more torque from the powertrain. An internal
combustion engine (especially diesel) has a certain delay in delivering the requested torque. The torque response
delay of the internal combustion engine has several causes:
• the inertia of the air in the intake manifold
• the mechanical inertia of the moving parts
• the torque limitation (to prevent smoke in the exhaust)
In these situations, called torque transients (engine is changing the operating point), the electric motor can
assist, providing additional torque, which compensates for the engine torque response delay. This function is
called torque filling.
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An internal combustion engine has a maximum torque capability, which depends on the engine
speed. By adding the electric motor torque, additional to the engine torque, the maximum overall
torque of the powertrain is increased (positive offset). This function is called torque boost and
can be supplied only for a short duration of time (order of seconds) due to battery depletion.
The function of electric torque assistance is usually provided by mild hybrid electric vehicles
(MHEV), full hybrid electric vehicles (FHEV) and plug-in hybrid electric vehicles (PHEV).
Honda IMA powertrain (MHEV)
80. Mahindra Intelli-Hybrid
Mahindra Scorpio 2.2-litre mHawk with Intelli-Hybrid
technology.
Intelli-Hybrid technology reduces fuel consumption
by around seven per cent.
It achieves this by assisting the diesel engine with
electric power during acceleration.
The mild hybrid technology also automatically
switches off the engine within 3 seconds of the vehicle
being stationary.
Mahindra's Intelli-Hybrid technology utilises brake
energy to charge the battery.
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Just like the Micro Hybrid, the Intelli-
Hybrid technology also gets start-stop
technology.
Additionally, it offers power assist and
regenerative braking function.
To accommodate the Intelli-Hybrid
technology, Mahindra utilises a more
powerful 14V battery.
The conventional alternator has been
replaced by an electric motor which is also
mounted on the engine.
Mahindra calls it the 'Belt Driven Starter
Generator' or BSG and says that it performs
a power assist as well as energy re-
generation function.
This is what Mahindra
calls the 'Belt Driven
Starter Generator' or
BSG
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• The BSG acts like a generator by recovering
the kinetic energy which usually gets lost
during braking and converts it to electricity.
• This is in turn utilised to charge the battery.
• The sensors and controllers can detect when
the vehicle is braking and switches into
generator mode. It then harnesses the
braking energy by working as a generator.
• This technology is effective while the
vehicle is being driven in typical rush hour
stop-and-go traffic.
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This diagram represents the power flow when
the BSG is performing a power assist function
• The sensors and controllers in the Intelli-
Hybrid system can also detect if the driver has
started to accelerate hard depending on the
accelerator pedal input.
• It then goes into power assist mode, and the
BSG begins to function like a typical electric
motor.
• It takes power from the re-generated energy
stored in the battery and augments the engine
torque.
• It assists the diesel engine during overtaking
manoeuvre by providing additional power.
• Mahindra says that by playing this dual role
and enabling better power optimisation, the
Intelli-Hybrid system improves the engines
efficiency.
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• The entire battery management system has been
developed completely in-house.
• The electric motor has been sourced from Valeo while
Bosch has developed the software which controls its
interaction with the diesel engine.
This is a schematic diagram of the Mahindra
Intelli-Hybrid technology
• Compared to the Micro Hybrid system, the Intelli-Hybrid
offers a bit more technology on paper.
• The powertrain has been modified to accommodate the BSG,
and the front-end auxiliary drive is revamped.
• The Scorpio Intelli-Hybrid is more fuel-efficient than the
Scorpio Micro Hybrid.
• Also, as per standard MIDC test cycles, the Scorpio Intelli-
Hybrid is around 7 per cent more efficient than the regular
version.
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The ratio of power developed by an electric motor in a
hybrid vehicle to the total power consumed by the
vehicle is known as degree of hybridization.
87. Power flow control
Due to the variations in HEV configurations, different power control strategies
are necessary to regulate the power flow to or from different components. All the
control strategies aim satisfy the following goals:
maximum fuel efficiency
minimum emissions
minimum system costs
good driving performance
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88. Power flow control
The design of power control strategies for HEVs involves
different considerations such as:
Optimal ICE operating point
Optimal ICE operating line
Safe battery voltage
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Function of the Control System in HEVs and EVs
The major functions of the control system are:
i. to maximize the fuel efficiency
ii. to minimize the exhaust emissions.
The minor functions of the control system are component monitoring and
protection such as:
i. Battery state of charge (SOC) monitoring
ii. Battery temperature monitoring
iii.EM overheating
iv.ICE overheating
94. Plug-in Hybrid Electric Vehicle
Plug-in hybrid electric
vehicles (PHEVs) use
batteries to power an electric
motor and another fuel, such
as gasoline, to power an
internal combustion engine
(ICE). PHEV batteries can
be charged using a wall
outlet or charging
equipment, by the ICE, or
through regenerative
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Possible energy management modes that are relevant to PHEVs include:
• Charge-sustaining mode—A mode where the battery state-of-charge is controlled
to remain within a narrow operating band. This is the mode that conventional HEVs
operate in for most of the time . Because the battery state-of-charge does not change
with time, liquid fuel is the net source of energy for the vehicle.
• Charge-depleting mode—A mode where the battery state-of-charge is controlled so
as to decrease during vehicle operation. In this mode, the engine may be on or off,
but some of the energy for propelling the vehicle is provided by the electrochemical
energy storage system, causing the state-of-charge to decrease with time.
• Electric vehicle (EV) mode—A mode where operation of the fuel converting
engine is prohibited. In this mode, the PHEV drives as an electric vehicle. Because
the electrochemical energy storage system is the only sources of tractive energy, the
state of charge decreases with time.
• Engine only mode—A mode where operation of the electric traction system is very
limited. In this mode, the electric traction system does not provide tractive power to
the vehicle.