Automobiles are a source of considerable pollution at the global level, including a significant fraction of the total greenhouse gas emissions.
The new millennium is bringing a millennial change to the family car. A few years back, the key concerns were: Pollution, Nagging worries about global warming, and Oil shortages. These concerns led to the development of Hybrid Electric Vehicle (HEV’s) powered by batteries.
What is ybrid electric vehicle ? Hybrid electric vehicle(HEV) is a vehicle which uses an internal combustion engine(IC engine) as well as an batteries for its running . Basically , it takes power from the internal combustion engine as well as from the batteries. IC engine used in HEV’s is basically a gasoline engine. Hev’s can go upto 300 miles per hour.
Parts of Hybrid electric vehicle HEV consists of : 1). Internal combustion engine. 2).An electric motor. 3).batteries. 4). Power split device. 5).Generator.
Functions Internal combustion engine: In Hev’s gasoline engine is used. The gasoline engine in hev is much like those in conventional engine except that it is much smaller and more efficient.
Electric motor: The electric motor powers the vehicle at low speed and assists the gasoline engine when more power is needed.Italso converts otherwise wasted energy from braing into electricity and stores it in the batteries.
Generator: The generator converts mechanical energy from the engine into electricity which can be used by the electric motor or can be stored in the batteries.It is also used to start the gasoline engine instantly when needed.
Batteries: Batteries store energy generated from the gasoline engine or, during regenerative braking, from the electric motor.since the batteries powers the vehicle at low speeds.Itis larger and holds much more energy than batteries used to start conventional vehicles.
Power split device: It is a gear box connecting the gasoline engine,generatorand the electric motor.It allows the engine and the motor to poer the car independently nd allows the gasoline engine to charge the batteries or provide power to the wheels as needed.
Working of Hev Hybrid-electric vehicles (Hev’s) combine the benefits of gasoline engines and electric motors and can be configured to obtain different objectives, such as improved fuel economy, increased power, or additional auxiliary power for electronic devices and power tools.
HEV layout Wheel Wheel IC Engine IC Engine Transmission Generator Battery Transmission Generator Battery Motor Motor Wheel Wheel Scenario 2: Braking – Kinetic energy is converted to electric energy during regenerative braking by electric motor and supplied to battery. Scenario 3: High speed – Power is provided by IC engine and electric motor via generator. Generator also charge battery during high speed. Scenario 1: Low speed - Power is provided by electric motor using energy supplied by the DC battery Wheel IC Engine Transmission Generator Battery Motor Wheel
Hev advantages a) Even if an alternate fuel source for vehicles is uncovered immediately, it will take a lot of time to modify the current design of engines to function with the new fuel properly. Hence, HEV might be the best choice for us at this moment. b) Even though the initial cost of HEVs is high, their operating costs are lower in the long run. Since part of the energy is derived from batteries, the requirement for fuel decreases and so does the cost of maintenance. c) Wear and tear on the engine components decreases and hence they function accurately for a longer period of time.
d) Use of electric motor for locomotion decreases noise pollution. Most of the old conventional vehicles give out a lot of noise, which causes health problems. e) With decrease in the consumption of fuel, air pollution also decreases. f) Engine of smaller size and power can be used, making it possible to minimize losses and improve efficiency of the HEV. g) In some cases, the energy saved by the RESS is also used to provide additional accelerating power to the vehicle. h) These vehicles consume less fuel than the conventional internal combustion engines. They provide 40% better fuel efficiency than conventional vehicles, making them extremely cost-effective.
Hev disadvantages Hybrid electric vehicles are not all-electric vehicles. They dorequire gasoline to drive. Hybrid electric vehicles use regenerative braking to get theirelectricity. The gas energy is captured off of the brakes and stored aselectricity. All electric vehicles are a much better alternative in terms ofcutting down smog. There are several available today. Hybrid electric vehicles are also inferior to hydrogen fuel cellvehicles. Many automotive companies are working on hydrogen fuel cellvehicles in production now. Very soon Chevy will come out with a hydrogen fuelcell vehicle.
While hybrid electric vehicles are low smog emission vehicles, they doproduce emissions. Hydrogen fuel cell vehicles produce water as theiremission, making them far superior to hybrid electric vehicles. Orbetter yet take public transportation in a city that uses hydrogen fuel cellbuses. Although hybrid electric vehicles are readily available, they are alarge investment. There are sometimes $10,000 difference in between ahybrid car and a subcompact although the mile per gallon difference couldbeonly a few miles freeway miles. This is an investment that might not be immediately recaptured in gas savings.
Why do we use hev’s? 1). Need to reduce pollution and hence to stop global warming. 2). Need to conserve coal and petroleum for future generation.