Transcript 2.9 Electric Cars and Hybrid vehicles

Programme : Automobile Engineering. (AE)
Course: Advanced automobile
Engines (17523)
Semester : Fifth
PPT of topic
§ Electric Cars and Hybrid vehicles
- Electric Cars
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Electric Cars and Hybrid vehicles
Electric Cars
● The electrical vehicles (EV) are quiet,
produce no exhaust emission and are very
efficient.
● Depending upon the application, battery
powered electric vehicles can be classified asroad vehicles or industrial trucks.
● Industrial trucks are used for transporting
goods on company premises. Their top speed
is below 50 Km/hr.
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● Due to low power density of batteries, the
range of battery powered on-road vehicles is
very less than that of vehicles powered by I.C.
Engines (ICEs). The maximum speed of such
vehicles is also limited to around 130 Km/hr.
● The price of EVs are significantly higher than
comparable vehicles using ICE.
● Increasing air pollution prompted the
development of experimental EVs. Petrol
shortage in 1970s, renewed the interest in
EVs.
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Electric Cars and Hybrid vehicles
● Major Problems- The major problem with EVs
was their relatively small operating radius
(traditional fuel has about a 20 times greater
energy density than batteries).
● Present day EV performance is less than that
of ICE vehicles as demonstrated below.
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Parameter
Internal
Combustion
Engine- Vehicle
Electric Vehicle
1) Operating
Range
750 to 1100 Km
Less than 180 Km
with tank full of fuel
2) Refueling
5 to 10 Minutes
In hours (battery
charging)
3) Energy Density 12000
of Fuel
Wh/kg
30 to 35
Wh/kg
4) Speed
200 Km/hr
120 Km/hr
5) Acceleration
Higher acceleration Lesser high speed
at high speeds
acceleration.
(from 110 km/hr)
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Parameter
Internal Combustion
Engine- Vehicle
Electric Vehicle
6) Hill Climbing
ability
More
Significantly less
7) Initial cost
Less
Significantly high
8) Operational
Cost
More
Should be less
9) Maintenance
More
Significantly less
10) Vehicle
lifetime
Lesser (Maximum 15 Significantly
years)
longer.
11) Battery
Maintenance
Less
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High maintenance
and short life span
of battery (few yrs)
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●Motivations to use Electric Vehicles
1) Zero Exhaust Emission
2) Reduced dependency on Imported Oil
3) Electric vehicles can be charged at night
during off-peak hours (Increased utilization
of existing power plants and reduced
energy costs)
● Drawbacks of Electric Vehicles
1)Resultant increase of lead emissions into
the air. Most EVs use lead acid batteries.
The production, handling and recycling of
these batteries increase the emission of lead
to the environment.
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● Drawbacks of Electric Vehicles
2) Switching to electric powered vehicles will
reduce pollution levels but will increase the
consumption of electricity, thereby increasing the
air pollution produced by electric power
generation at the power stations.
3) Battery requires high maintenance and has a
short life span. Therefore cost of batteries should
be considered as a part of operating expenses
for an electric vehicle.
4)Lead acid battery has short range, long
charging time and low energy density. Nickel
cadmium batteries have high energy density but
have significantly higher prices.
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● Drawbacks of Electric Vehicles
5)Most EVs use expensive electronic
components and microprocessors. Consequently
the initial cost of EV is significantly higher than
that of a Petrol powered vehicle.
6) A road side service may involve changing the
battery pack- instead of quick charging
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Drive Trains
The drive train in an EV generally consists of the
power controller, the motor and transmission.
The power controller translates the position of
the accelerator pedal into appropriate motor
current and voltage. In most cases, the drive
torque is a function of accelerator pedal position,
as in case of IC engines.
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Major components of Battery EV
1) Charger- It rectifies the AC network voltage for
charging the batteries.
2)Protection system- It has circuit breakers, relays
and fuses that are connected between the
batteries and the rest of electrical system and
interrupt the AC supply and/or isolate the
batteries in case of fault.
3) Motor- This is used to drive the EV. EVs use
both AC and DC motors.
4) Motor Controller- This system controls the drive
motor speed and torque. Both AC and DC drives
are used.
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Major components of Battery EV
5) Mechanical Drive System- It consists of the
transmission, differential, power steering and
other non electrical controls required for the
motor drive.
6) Vehicle Controller- Most advanced EVs use a
microprocessor based controller that monitors
the status of each of the major components and
initiates controls and protection action as
needed.
7)Batteries- the battery pack provides energy for
the vehicle propulsion.
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Major components of Battery EV
8) Climate control system- This system includes
efficient air conditioning and heating system.
9) Auxiliary power- it supplies power to the head
lights, instrumentation, door opener, auxiliary
motor (ex. sunroof) and power steering etc.
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Location of Major components
It depends upon the vehicle type and construction.
Generally batteries are placed at the middle of
the vehicle under the seat. Electric motor is
directly connected to the transaxle, which drives
either the front or rear wheels. The inverter and
electronics are placed near the motor.
With front wheel drive, the motor and drive
are under the hood at the front. The same
equipment is placed under the cargo bay in a
rear wheel drive pick-up. The charger is located
at the front in most of the vehicles.
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Block Diagram of Electric Drive Unit in Battery Powered Electric on road vehicle
Power
Mains
On-board
Battery Charger
Traction
Battery
Traction
Control
Drive
Motor
Mechanical
Braking System
DC Converter
Electrical
System Battery
Single Stage
Transmission
Wheel
Brake pedal
Accelerator pedal
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