Modifications are needed in gasoline engines to use ethanol fuel blends. For blends up to E10, no changes are typically needed. For higher blends, modifications like increasing the diameter of inlet orifices and the accelerator pump are required to properly adjust the air-fuel ratio. Additional changes like increasing the compression ratio or installing pre-heating systems may be needed for cold starting when using high-ethanol blends. Proper adjustments can help utilize the higher octane and cleaner burning properties of ethanol fuel in engines.

1. SHRI RAMDEOBABA COLLEGE OF
ENGINEERING AND MANAGEMENT
Technical seminar on
MODIFICATIONS IN GASOLINE ENGINES
FOR USE OF ETHANOL
Guided by: Presented by:
Prof. M. P. Joshi Sughosh Deshmukh
Mechanical Engg. Dept V sem Mechanical Engg.

2. PROPERTIES OF ETHANOL
Molecular formula C 2H 6O
Appearance Colorless liquid
3
Density 0.785 g/cm
Melting point −114 °C, 159 K, -173 °F
Boiling point 78.37 °C, 352 K, 173 °F
Vapor pressure 5.95 kPa (at 20 °C)
Viscosity 0.0012 Pa s (at 20 °C)

3. ENERGY CONTENT OF SOME FUELS
Fuel MJ/L Research
octane
number
Methanol 17.9 108.7
Ethanol 21.2 108.6
E85 (85% ethanol+ 15% 25.2 105
gasoline)
Gasohol (90% gasoline + 33.7 93/94
10% ethanol)
Regular gasoline/petrol 34.8 min. 91
Premium gasoline/petrol max. 104
Diesel 38.6 25

4. Properties of ethanol
 High auto ignition temp.: 326o C (petrol 240-280o C,
diesel 210o C)
 Corrosive in nature.
 High octane rating.
 Lesser energy content than gasoline /diesel.
 Contains more oxygen

6. MAINJET CHANGES
Allows entry of air fuel in cylinder.
 Greater octane number than petrol.
 Requires greater compression ratio.
 Increase in orifice diameter of the main jet.
 Needs increase of 20 to 40%.

7. IDLE ORIFICE CHANGES
For entry of fuel in idle mode
 Idle orifice needed for supply of air-fuel mixture in
slow speeds or idle states.
 Diameter to be increased for proper supply of
mixture.

8. POWER VALVE CHANGES
vacuum-controlled valve, spring loaded, shuts off, to conserve fuel.
 Power valve allows extra fuel to blend with the
air/fuel mixture when the accelerator is depressed.
 Difficult to alter.
 Valve with approx. 25% greater flow capacity
sufficient for increased power.

9. ACCELERATOR PUMP CHANGES
Supplies extra fuel on sudden accelerator pressing
 Used to inject fuel when accelerator is suddenly
depressed.
 Increase the size approx by 25%.
 Larger size may create difficulty in reverting back to
gasoline.

10. A SMALL GIST
 More compression is needed in the cylinder during
stroke, to utilize the full potential of the fuel.
 Hence, the inlet diameters of the orifices which let
the fuel in are to be increase.

11. COMPRESSION RATIO CHANGES
 Ethanol has a good octane rating.
 Compression ratios up to 15 : 1 may be suitable.
 Difficulty in reversing back to gasoline.
 Remedy: installation of Water injection system for
cooling to revert back to gasoline.

12. COMPRESSION RATIO CHANGES
……continued
 Use of high  Installing a
compression pistons. turbocharger.
 Connecting rods and  No excessive
bearings may not compression during
tolerate high ratios. engine startup.
 May be replaced.

13. COLD WEATHER STARTING
 Alcohol does not vaporize as easily as gasoline.
 Therefore, starting the engine in cold conditions is a
problem.
 Various remedies for this are:
 Use of extra fuel tank for petrol.
 Use of fuel preheater.
 Use of air preheater.

14. FUEL PREHEATING
 Necessary to pre heat fuel in cold climates.
 Can be done by making the fuel flow over the hot
engine parts through tubes.
 Time consuming.
 Not very effective.

15. AIR PREHEATING
 Air from around the exhaust manifold is let in the air
fuel mix through ducts.
 A flap within the air cleaner "snorkel" shuts off this
supply when engine warms up and allows ambient
air enter.
 This flap is usually either thermostatically or vacuum
controlled .
 External type resistance air heater may also be
used.

16. AIR PRE-HEATER SCHEMATIC
Resistance
Normal air in
To electric supply.
Warm air out

17. THERMOSTAT CHANGE
 Used to hold the coolant in the cylinder head until it
reaches a certain temperature.
 Thermostat decides the temperature at which the
coolant will enter the cylinder head.
 Ethanol engine works at less temperature than petrol
engine of same horsepower.

18. INITIAL USE OF ALCOHOL FUEL
 Alcohol will act as a cleansing agent and will clean
out fuel tank, fuel lines, and filters, remove engine's
internal parts of built-up carbon, gum, and varnish
deposits.
 Suddenly a lot of filth will be floating around in fuel.
 It may clog fuel filter to the point of not allowing any
fuel to pass.
 Loosened internal engine deposits can foul the spark
plugs badly.

19. FUEL INJECTION SYSTEMS
 Many vehicles equipped with fuel injection systems
instead of carburetors.
 Effect same as increasing the main jet diameter and
idle orifice diameter.

20. BENEFITS OF USING ETHANOL FUEL
 Has complete combustion.
 Little CO2 formed.
 Does not contain sulphur.
 Emissions and pollution is reduced.
 Cheaper than gasoline and diesel.
 Keeps engine clean.
 Can be produced from grains and sugarcane.

21. DISADVANTAGES OF ETHANOL FUEL
 Has low energy content.
 More fuel needed to obtain same
energy as obtained by petrol.
 Has poor ignition characteristics.
 Has almost invisible flames.
 Odour is very offensive.

22. Require no Require
change in changes in
engine engine

23. [edit]
CONCLUSION
Required adjustments in gasoline engines to cope up with different blends of
ethanol fuel
Carburet
syste
Motor oil
manifold
injection
Exhaust
pum
filter
tank
Ethanol
Fuel pr.
Ignition
system
Device
Intake
blend
m
p
Cold
syst.
start
Fuel
Fuel
Fuel
Fuel
or
0
≤5%
E5-
E10
E10-E25
E25-E85
E85-E100
Modifications needed No modifications needed

24. REFERENCES
 Internal Combustion engines- V Ganesan, 4th edition TMH
publications.
 "Sustainable bio-fuels: prospects and challenges”
Joseph (2007) in The Royal Society (2008) journal.
 Hydrous ethanol vs. gasoline-ethanol blend: Engine
performance and emissions- Rodrigo C. Costa, José R.
Sodré Pontifical Catholic University of Minas Gerais, Department of
Mechanical Engineering, MG, Brazil.
 en.wikipedia.org/wiki/Ethanol
 running_on_alcohol.tripod.com
 Image source: Google.