Hybrid Electric Vehicles 1

8/4/2019 Hybrid Electric Vehicles 1

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Hybrid Electric Vehicles (HEV) (Clean & Fuel Saving Technology)

ABSTRACT

Today automobiles are identified as one of the major causes of air pollution and energy

depletion. Vehicles are also identified for their low efficiency in other words high-energy

loss. Hybrid Electric Vehicles have the capacity to overcome these situations and bring anew revolution.

Any vehicle that combines two or more sources of power that can directly or indirectly

provides propulsion power is a hybrid. The gasoline electric hybrid vehicle is just therequired type of crossbreed between a gasoline powered vehicle and electric vehicle. Hybridvehicles run both with a rechargeable battery as well as gasoline. In a hybrid engine, power

from gasoline and power from a set of batteries transmits power to an electric motor. Thereare less adverse effects due to the Hybrid electric vehicles. Also the batteries used in hybrid

vehicles (rechargeable Nickel metal hydride, Lead acid batteries, Lithium Polymer batteries)are disposable which will not pose any toxic hazards to the environment. The notable fact in

hybrid vehicles is that the DC machine is that it can run both as a Motor as well as agenerator.

In addition, hybrid vehicles make use of a system that recovers power from the momentum

of the vehicle when braking. The Hybrid vehicles are complicated machines when comparedto their counterparts of the gasoline-powered vehicles. But higher efficiencies, lower

emissions of hybrid vehicles grabs the attention of the new ERA. The other facilities of these

hybrid vehicles i.e. performance, manufacturing cost and environmental impacts are

discussed in this paper.

Key Words: Hybrid, DC Generator, DC Motor,

1. INTRODUCTION:

The main problem the world is facing is environmental pollution. The major reasons for thepollution are industrialization, burning of fossil fuels, internal combustion engines etc. Many

problems are being faced due to the usage of fossil fuels.

Some of these problems are:1. Global Warming2. Toxic Emissions

3. Drilling and Transport of fossil fuels

4. Dependence on Foreign OilIn order to overcome the problem of pollution, many alternative methods are in developing

stage. Among these some of them are:

1. Solar energy

2. Fuel cells3. Electric vehicles

4. Hybrid vehicles

Let us see the advantages and disadvantages of all these sources:1.1. SOLAR ENERGY:

? Abundant energy.? There is no pollution.

? Eliminates environmental concerns.? Many times climatic conditions dont support use of solar energy.

With The existing technology we cannot produce the silicon plates with less cost and ease.

1.2.HYDROGEN FUEL CELLS:? Hydrogen is abundant but not in its pure state.

? Eliminates environmental concerns.


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? Extraction of hydrogen is extremely difficult with the existing technology.

1.3.ELECTRIC VEHICLES:

? Causes no pollution.? ECO-friendly.

? Applicable only to lighter vehicles

? Involves high manufacturing cost.

? Not enough power output.?Experts hope that vehicles based on solar energy are expected to reach its full

development by 2020.?Fuel-cell vehicles have still a long development-path to go and to eliminate constraints like

weight & costs reduction, manufacturing technologies etc. It is estimated that productionwill start not before 2015.

?Electrical vehicles involve high cost, which cant be afforded by a normal person. And it

does not reach the customers requirements.

All the above three systems are ECO-friendly but not par with a customers requirements.Thus high cost involved in first 3 choices made the customers to attract towards the ICengines, which are available in affordable price and easy management. Among above

choices, electric vehicles are developed to maximum extent but it requires lot of money.

Thus a combination of an IC engine and the Non-conventional sources are used to be both

ECO-friendly and User friendly. This is called a hybrid.2. DEFINITION:

Hybrid vehicle consists of engine with atleast 2 different energy converters and 2 different

energy sources for the vehicle propulsion.Thus hybrid engines meet the requirements of the standard vehicle which:

? Increases fuel economy.

? Reduces pollution.? Decreases dependence on fossil fuels.

? Keep up with the other traffic on the road.

3. TYPES:

A gasoline-electric car combines two set ups both IC engines and electric vehicles into onesystem that runs on both fuel power and electric power. There are two different kinds of

hybrid structures of arrangements in this setup.They are. i. A series hybrid vehicle

ii. A parallel hybrid vehicle3.1. SERIES HYBRID ELECTRIC VEHICLES:

It has tank that pumps gasoline to the engine

Engine rotates the DC Generator

Generator can either charge the batteries or power an electric motor Only the electric motor drives the transmission

3.2. PARALLEL HYBRID ELECTRIC VEHICLES:It has fuel tanks that supply gasoline or diesel to engine.

Both engine and electric motor can rotate the transmission at the same time when morepower is required.

Capable of working simultaneously and independently.

4.How it works:

The goal of a Hybrid engine is to reduce the amount of pollutants, a normal IC engineproduces and more energy-efficient. Thus several methods used to try to achieve this goal

include:

1. More efficient use of the internal combustion engine (ICE), reducing gasoline


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consumption. A more efficient Atkinson cycle can be used instead of the more common Otto

cycle engine.

2. Two electric motor/generators, providing minimum of 50 kW @ 1,200 to 1,540 rpm and400 Nm torque from 0 to 1,200 rpm, which significantly contribute to performance &

economy.

3. Regenerative braking, a process for recovering kinetic energy when braking or traveling

down a slope and storing it as electrical energy in the traction battery for later use whilereducing wear and tear on the brake pads.

4. By using sealed Nickel metal hydride (NiMH) or Lithium polymer batteries the electricalenergy can be stored effectively.

The Mercedes-Benz M-Class Hyper -- a hybrid concept vehicleThe hybrid engine discussed in this paper over previous energy-efficient designs is that it

never needs to be plugged in, as all energy ultimately comes from the gasoline engine. This

means it drives like a traditional ICE automobile. This hybrid engine recovers energy that

would be wasted when braking. The car's kinetic energy is partly recovered to recharge thebattery instead of being wasted as heat. This also reduces brake wear. This hybrid enginecan then be driven on electric power only. This is sometimes referred to as "stealth mode"

due to the lack of engine noise. This further reduces gasoline consumption and wear and

tear on the engine.

For any car, aerodynamic losses due to drag are much greater on the highway than in lowspeed city driving. A non-hybrid car nonetheless gets worse mileage in city driving becauseits engine is far less efficient at low power(for example when stopped in traffic) as it must

frequently dump its kinetic energy into the brakes during stop-and-go driving. Hybridengine gets better fuel efficiency in city dynamometer cycles because the engine can shut

down instead of running at low power, and run solely off the battery at low speeds and

when stopped (simultaneously running the cabin air heating/cooling system and the powersteering).

5.Stealth ModeWhen the vehicle is turned-on with the "start" button, it is ready to drive immediately withthe electric motor. The delay between starting the car and starting the internal combustion

engine is few seconds. The Hybrid engine should be designed to protect the battery fromextreme discharge as well as over-charge and will utilize the engine as-necessary to

maintain the optimum conditions for a long battery life. This is sometimes referred to as"stealth mode" due to the lack of engine noise. This further reduces gasoline consumption

and wear and tear on the engine.

6.HYBRID STRUCTURE:

6.1.Electric Storage Devices: -One of energy suppliers in a hybrid car is the electric storage devices. This is the main

component, which differentiates HEV from the conventional vehicles (ICE). It is the main

reason for HEVs characteristics like: no pollution vehicles and energy saving vehicles.To satisfy the customer wants electric storage devices should have the following

characteristics:? Discharge quickly: so that it can supply enough power during acceleration of the vehicle.

? High specific energy? Low manufacturing cost

? Safety

? Long cycle life? Charge quickly from variety of sources

6.2. Types of electric storage devices: There are three types of energy storage devices are

developed so far. They are as follows:


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? Internal Resistance increased at low temperatures

7.Hybrid Efficiency and Performance:The key to a hybrid vehicle is that the gasoline engine can be much smaller than the one ina conventional car and therefore more efficient. Most cars require a relatively big engine to

produce enough power to accelerate the car quickly. In a small engine, however, the

efficiency can be improved by using smaller, lighter parts, by reducing the number ofcylinders and by operating the engine closer to its maximum load.

To squeeze every last mile out of a gallon of gasoline, we can: Recover energy and store it in the battery

Sometimes shut off the engine Use advanced aerodynamics to reduce drag

Use lightweight materials

Conclusions:

By using a Hybrid Electric engine we can not only reduce Environmental pollution but alsoreduce the wastage of the depleting Fossil fuels. Though we are using an IC engine of about30-45% efficiency, the motors and generators we use are about 70-85% efficient. This may

bring the overall efficiency up to 50-70%. Also we can use the energy wasted by using

brakes which is about 12-15% of total efficiency. By taking the above measures we can

increase the mileage from a mere 12-20km/lt to about 25-30km/lt although the AirConditioner is running. This makes the Hybrid Electric Vehicles a sensation.

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Hybrid Electric Vehicles 1