This document provides an overview of alternative fuels that can be used in automobiles to replace or supplement gasoline. It discusses fuels like ethanol, methanol, biodiesel, natural gas, propane, hydrogen, and electricity. For each fuel, it covers their production methods, properties, advantages, and disadvantages for use in vehicles. It also describes different engine and vehicle technologies that can use these alternative fuels, such as flexible fuel vehicles, hybrid vehicles, and fuel cell vehicles.

1. UNIT-V
ALTERNATIVE FUELS

2. Introduction to alternative fuels
 Improve both environment and reduce
india dependence on imported petroleum
Fuels identified include two alcohols
1. Ethanol 2. methanol
Fuel gases at normal temp and pressures,
liquefied petroleum gas, natural gas and
hydrogen

3. Reason for alternative fuels
• Crude oil and petroleum products will become
scarce and costly to find and produce.
• Motivating the development of alternate fuels
for IC engine Is the concern over emission
problems of gasoline engines

4. 1. LPG – consists mainly of propane, propylene,
butance and butylene in various mixtures
2. Biodiesel is a clean burning alternative fuel
produced from domestic, renewable
resources such as soybeam oil or recycled
grease.
3. Ethanol-

5. Properties of alternative fuels
• Energy density: Petrol and diesel which liquids have
higher energy density
• Ethanol and methanol are liquids at atmospheric
pressure and ambient temp
• LPG gas at normal temp and pressure is stored in a
liquid form under the pressure
• Both propane and butane have lower energy content
• Natural gas is stored in the vehicle fuel tanks under
pressure as a compressed gas. Both high pressure and
energy density is less
• Hydrogen is less dense than natural gas

6. • Volatility : Controlled for both engine performance and
emissions.
• Octane number : is a measure a fuel’s tendency to knock in
a SI engine. Knocking occur when the gasoline air vapour
mixture prematurely self ignites as the mixture is
compressed during the upward movement of the piston.
• Cetane number: Ignition characteristics of CI engine fuels.
High octane number means a low cetane number.
• Heat of vapourization: Affects both engine power and
efficiency. High heat of vaporization leads to improved
cooling ability.
• Flame speed:
• Flame temp and luminosity
• Flash point
• Flammability

7. Natural Gas in Automobiles:
• Natural gas is a fossil fuel such as petroleum and
coal. The main ingredient is methane.
• Cars, vans, buses and small trucks are use natural
gas which has been compressed called compressed
natural gas stored at high pressure cylinders.
• Properties:
• Colourless, odourless, tasteless, shapeless and
lighter than air.
• It is not possible to see and smell natural gas.
• Natural gas is mixture of light hydrocarbons
including methane, ethane, propane, butanes and
pentanes.
• It is neither corrosive not toxic

8. Methane(CH4):
• As a hydrocarbon is considered non-reactive
• Do not react with sunlight to create smong
• It is used engine fuel & SAE
Advantages
• It has very low emissions, toxies and carbon
monoxide
• It can be made from a variety of feed stocks including
renewable
• It is excellent fuel
Disadvantages
• Vehicle cost is higher
• Vehicle range is lower
• It has less convenient refueling

9. Ethanol: Ethanol called grain alcohol. It is used many
year in US
• Pure ethanol fuel offers the excellent performance
and low hydrocarbon and toxic emissions
• It can produced domestically from corn and cellulose
materials such as wood or paper wastes .
Advantages:
• It is excellent automotive fuel
• Very low emission of ozone forming hydrocarbon and
toxics
• It made from renewable soures
• It can be domestically produced.
Disadvantages:
• Fuel cost is high
• Vehicle range is somewhat lower

10. Methanol:
• High performance liquid fuel which emits low level
toxic and ozone forming compounds.
• It is excellent automotive fuel
• It is very low emissions
• It can be made from a variety of feedstock including
renewable
Disadvantages
• Vehicle cost is high
Propane:
• It is cheaper than gasoline today
• It is widely available clean fuel today
• Emissions are less
• Excellent fuel especially for fleet vehicle.

11. LPG
• LPG is mixture of propane and hydrocarbon gases
• LPG is stored in special tanks which keep it under
pressure. It stays as liquid
• Very low sulphur level
• Low cold start emissions due to its gaseous state
at ambient pressure and temp
• Relatively high octane number with propane
having the best antiknock properties relative to
other component.
• Lower peak pressure during combustion and
reduce noise and improves durabilty

12. • USE OF BIO-DIESEL IN AUTOMOBILES
• Biodiesel is fuel derived from vegetable oil or animal fats.
• Biodiesel made from soybean or canola oils and waste
stream sources such as used cooking oils or animal fats.
• Biodiesel is mixed with conventional diesel because of high
cost of biodiesel.
• B100: 100% biodiesel offers the most environmental
benefits.
• B20: 20% biodiesel offers about one fifth of the
environmental benefits of B100 but it can be more broadly
applied to existing engines with little or no modification.
• B2: 2% biodiesel offers little environmental or petroleum
dependence benefit and it could be potentially used an
environmental marketing tool.

13. Biodiesel production:
• Biodiesel fuel made from new or used vegetable oils and
animal fats which are nontoxic, biodegradable and
renewable resources.
• Fats and oils are chemically reacted with an alcohol to
produce chemical compounds known as fatty acid methyl
esters.
• Glycerol is produced as a co-product.
• There are three basic routes to ester production form oils
and fats.
• Base catalyzed transesterification of the oil with alcohol.
• Direct acid catalyzed esterification of the oil with
methanol.
• Conversion of the oil to fatty acids and then to Alkyl esters
with acid catalysis.

14. • Biodiesel is produced from vegetable oils by
converting the triglyceride oils to methyl esters with
a process known as transesterification.
• In transesterification process, alcohol reactswith the
oil to release three “ester chain” from the glycerin
backbone of each triglyceride.
• The reaction requires heat and a strong base catalyst
to achieve complete conversion of the vegetable oil
into the separated esters and glycerin.
• Methanol is charged in excess to assist in quick
conversion and recovered for reuse.
• Glycerin can be further purified for sale to the
pharmaceutical and cosmetic industries.
• Biodiesel is nearly 10% oxygen by weight.

15. • Advantages:
• Special pumps or high pressure equipment for fueling is not
needed because little fossil energy is required to move
biodiesel.
• Biodiesel is made entirely from vegetable oil, it does not
contain any suplhur, aromatic hydrocarbons, metals or
crude oil residues.
• Lack of toxic and carcinogenic aromatics in biodiesel
reduces impact on human health and the environment.
• High cetane rating of biodiesel, so improve the combustion
efficiency.
• Biodiesel offers safety benefits over petroleum diesel.
• It is safe to handle, store and transport.
• It can be used in conventional diesel engines, the
renewable fuel can directly replace petroleum products by
reducing the country’s dependence on imported oil.
• Clean biodiesel reduces carbon dioxide emissions

16. • Bio-Ethanol in automobiles:
• Ethanol fuel is ethyl alcohol which is found as the
similar types of alcohol in alcoholic beverages.
• It is used as a motor fuel mainly as a bio-fuel additive
for gasoline.
• It can made from common crops such as sugar cane,
potato, manioc and corn.
• Bio-fuel offer benefits such as reduced emission of
pollutants and greenhouse gases and increased
employment is the agricultural sector.
• Ethanol can be produced from petroleum product.
• It is made by the catalytic hydration of ethylene with
sulfuric acid as the catalyst.

18. • GASOHOL IN AUTOMOBILES
• Gasohol is a mixture of 10% ethanol(ethyl alcohol) and 90%
unleaded gasoline.
• Most economic use of ethanol is as an octane booster in
gasoline.
• Gasohol is a much cleaner fuel than gasoline itself.
• Gasohol can be used without modifying the carburetor or fuel
injector, ignition timing or fuel lines of an automobiles.
• This fuel has higher octane value and anti-knock properties
than gasoline and burns slowly and completely results the
reduced emission of some pollutants.
• There are three primary ways that ethanol can be used as a
transportation fuel.
• 1.As a blend of 10% ethanol with 90% unleaded gasoline called
“E-10 Unleaded”
• 2.As a component of reformulated gasoline both directly and as
ethyl tertiary butyl ether
• 3. as a primary fuel with 85 parts of ethanol blended with 15
parts of unleaded gasoline calle”E-85”.

19. • Gasohol, a gasoline extender is made from a mixture
of gasoline (90%) and ethanol (10%) often obtained
by fermenting agricultural crops or crop wastes or
gasoline (97%) and methanol or wood alcohol (3%).
• Ethanol-based gasohol is expensive and energy
intensive to produce.
• Methanol based gasohol is also expensive to produce
and it is toxic and corrosive and its emissions produce
cancer-causing formaldehyde.
• Emission measurements showed a considerable
reduction in conventional pollutants such as CO,HC &
Nox during ethanol operation.
• The use of gasohol(mixture of gasoline and ethanol)
such a sE85 in different proportions in automobiles.
• Flexible fuel vehicles which can be operated on
different ratio of Ethanol and gasoline.

20. • Variable fuel vehicles are introduced and
operated.
• These vehicles are capable of operating on
unleaded fuel with ethanol mixture up to 85%
with out having to make any engine adjustments.
• The vehicle automatically adjusts for best
performance and emissions.
• It increase the volumetric efficiency of the engine
and reduces and required work input in the
compression stroke.
• It can improve the agricultural economies.

21. • HYDROGEN IN AUTOMOBILES
• Hydrogen is the lightest element which may someday
replace heavier compounds as source of energy for
transportation.
• Hydrogen odorless, colorless, diffuse gas to be collected.
• Hydrogen is the most abundant material in the universe,
very little of it exist in free form in the atmosphere.
• As a fuel, the hydrogen is used in the form of gas.
• This is considered as a secondary source of energy
because another from of energy is needed to produce he
hydrogen fuel.
• Natural gas and methanol provide much of the raw
material for hydrogen today.
• The hydrogen and oxygen in water can be dissociated with
an electric current in a process called electrolysis.

22. • Hydrogen has the highest energy content per
unit weight of any known fuel 120.7kj/g.
• It burns cleanly. Hydrogen is burnt with oxygen,
only by products are heat and water.
• Hydrogen has high combustion energy per kg
relative to other fuels.
• Volumetric energy density can be increased by
storing the hydrogen under increased pressure or
storing it at extremely low temperature as liquid.
• Hydrogen is highly flammable.
• Hydrogen can be produced from renewable
resources such as by reforming ethanol and by
the electrolysis of water.

23. • Methods of producing Hydrogen:
• 1.Biomass gasification and pyrolysis:
• This techniques for plat material(biomass) and fossil fuels
are similar to a number of downstream unit operations
being essentially same for both feed stocks.
• Biomass pyrolysis produces a liquid product such as
petroleum.
• 2. Electrolytic process:
• Electrolytic hydrogen production processes the use of
electrical energy to split water into hydrogen and oxygen.
• Electrolysis: In electrolysis, electricity is used to separate
water into hydrogen and oxygen. The electricity can come
from fuels such as coal or from renewable sources such as
nuclear, solar or hydroelectric power.

24. • 3.Water electrolysis:
• Electrolysis provides only a small % of the world’s
hydrogen most of which is supplied to application
requiring small volumes of high purity hydrogen.
• Research continues in the integration of
intermittent renewable resources with
electrolyzers for producing hydrogen to be used as
a fuel or energy storage.
• 4.Reversible fuel cells / electrolyzers:
• Operating the proton exchange membrane fuel cell
“in reverse” as an electrolyzer is possible but
optimum operating conditions are for the power
production mode and for the hydrogen production
mode, they are significantly different.

25. • 5. Photolytic processes:
• This processes use the energy from sunlight to split
water into hydrogen and oxygen.
• Emerging direct water-splitting technologies include
photo biological and photo-electrochemical systems.
• Methods of using Hydrogen in CI Engines:
• Method:1 Hydrogen is introduced with air and using
spray of diesel to ignite the mixture i.e by the dual
ruel mode. The limiting condition are when the diesel
quantity is too small to produce effective ignition i.e
failure of ignition and when the hydrogen-air mixture
is so rich that the combustion becomes unacceptably
violent. In between these limits, a wide range of
diesel to hydrogen proportions can be tolerated.

26. • Method 2
• In this method, hydrogen is directly injected into
the cylinder at the end of compression and the
gas spray is made to impinge ona a hot glow plug
in the combustion chamber i.e by surface ignition
since the self-ignition temperature of hydrogen is
very high. It is also possible to feed a very lean
hydrogen-air mixture during intake into an engine
and then it injects the bulk of hydrogen towards
the end of compression stroke.

27. • Electric vehicles:
• Battery powered vehicles give off virtually no
pollution and offer one of the best options for
reducing motor vehicle emissions in polluted cities.
• Electric vehicle car is limited by the amount of
power and the battery can provide.
• Cost is high
• They use electricity stored on the car in batteries.
EV’s have an electric motor which turns wheels and
a battery to run.
• Electricity, the same energy that lights lamps and
runs TV is stored in batteries on an EV.
• The batteries can be lead acid batteries or Ni
cadmium. EV batteries must be replenished by
plugging in the vehicle to a power source.

28. • EV’s are zero emission vehicles
• More than 95% of the electricity used in domestic
resources.
Benefits:
• There is no pollution due to emission. i.e zero emission
• It ensures smooth operation. i.e vibration and noise is less.
• Cost of operation is less
• Less maintenance is required.
• It is easy to start the vehicle.
• It takes up less space on the road. So, they help to reduce
traffic congestion.
Limitations:
• It has less initial torque
• It is more expensive
• Frequent recharging of battery is needed and also battery
charging needs more time.

29. Electric vehicles

31. • HYBRID VEHICLES
• The word hybrid means, something is mixed
together from two things.
• Hybrid electric vehicles typically combine the
internal combustion engine of a conventional
vehicle with the battery and electric motor of an
electric vehicle.
• Hybrid electric vehicles are powered by two
energy sources such as an energy conversion unit
and an energy storage device.
• The energy conversion unit may be powered by
gasoline, methanol, compressed natural gas,
hydrogen or other alternative fuels.

32. • Parallel HEV design

33. • Series HEV design

35. • FUEL CELLS IN AUTOMOBILES:
• A fuel cell produces electricity directly form the
reaction between hydrogen and oxygen form air.
• The IC engine, the fuel burns in tiny explosions that
push the pistons up and down.
• Fuel cell, the fuel is also oxidized but the resulting
energy takes in the form of electricity.
• A fuel cell is an electrochemical device in which
chemical energy of a conventional fuel is directly
converted into low voltage DC electrical energy.
• Carnot limitation on efficiency does not apply
because the conversion can be carried out
isothermally.
• A fuel cell is frequently described as a primary battery
in which the fuel and oxidizer are stored in the
battery and fed to it as needed.

36. • The fuel gas diffuses through the anode and it is
oxidized.
• It releases electrons to the external circuit. The
oxidized fuel diffuses through the cathode and it is
reduced by electrons coming form anode by the way
of external circuit.
• Fuel cell is device which keeps the fuel molecules
from mixing with the oxidizer molecules in
permitting the transfer of electron by a metallic path
that may contain a load of available fuels
• The three key layers in fuel cell
• 1. Membrane electrode assembly
• 2.Catalyst
• 3. Hardware.

37. • Types of fuel cells
• Fuel cells are classified on the basis of electrolyte
used.
• It determines the type of chemical reactions that
take place in the cell. Kind of catalysts required,
temp range in which the cell operates, fuel required
and other factors.
• 1. Hydrogen –oxygen fuel cell
• 2.Polymer electrolyte membrane
• 3.Direct methanol fuel cell
• 4. Alkaline fuel cell
• 5.Phosphoric acid fuel cell
• 6. Molten carbonate fuel cell
• 7. Solid oxide fuel cell
• 8. regenerative fuel cell

38. • Polymer electrolyte Membrane:
• PEM fuel cells also called proton exchange
membrane fuel cells deliver high power density and
offer the advantages of low weight and volume
when compared to other fuel cells.
• PEM fuel cells use a solid polymer as an electrolyte
and porous carbon electrodes containing a platinum
catalyst.
• They need only hydrogen, oxygen from air and water
to operate. It does not require corrosive fluids
similar to some other fuel cells.
• They are typically fueled with pure hydrogen
supplied from storage tanks or onboard reformers.

39. • PEM fuel cells operate at relatively low tem around
80 C. Low temp operation allows them to start
quickly and it results less wear on system
components there by resulting better durability.
• Applications
• 1. They can be also be used for stationary
applications
• 2. They are used in central power stations.
• 3.Fuel cells have the potential to replace the internal
combustion engine in vehicles
• 4.Powering automobiles, buses cycles and other
vehicles.
• 5.Many portable device can be powered by fuel cells
such as laptop computers and cell phones.
• 6.They are used in spacecraft power stations.