Use of Natural Gas, Liquefied Petroleum Gas, Bio-diesel, Bio-ethanol, Gasohol and Hydrogen in Automobiles- Engine modifications required –Performance, Combustion and Emission Characteristics of SI and CI engines with these alternate fuels - Electric and Hybrid Vehicles, Fuel Cell Note: Practical Training in dismantling and assembling of Engine parts and Transmission Systems should be given to the students.

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 si 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 ot
other component.
• Lower peak pressure during combustion and
reduce noise and improves durabilty

14. FUEL CELL

15. TYPES OF FUEL CELLS
1. Hydrogen – Oxygen fuel cell
2. Polymer Electrolyte Membrane(PEM) fuel cell
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

16. Low temp Cell is operated at 90 degree celsius 4 atm. Pr
High temp Cell is operated at 300 degree celsius 45 atm. Pr

17. Solid polymer-electrolyte
Porus carbon- electrode

18. Potassium hydroxide-electrolyte

19. Teflon-bonded silicon matrix and porous carbon-electrolyte

20. Molten carbonate salt mixture suspended in a porous chemically inert ceramic lithium
aluminium oxide (LiAlO2)-electrolyte