Alchol As an alternative fuel for S.I ENGINE

Alcohol as an alternative fuel in S.I Engine

OUTLINE

INTRODUCTION E85 FUEL BLENDED ETHANOL BLENDING POWER MAKING FUEL CHARACTERISTICS FLEXIBLE FUEL VEHICLE ALCOHOL FUMIGATION ADVANTAGES DISADVANTAGES

INTRODUCTION

In this century, it is believed that crude oil and petroleum products will become very scarce and costly.

Day-after-day, fuel economy of engines is getting improved and will continue to improve . Enormous increase in number of vehicles has started dictating the demand for fuel.

With increased use and depletion of fossil fuels, alternative fuel technology will become more common in the coming decades.

Because of the high cost of petroleum products, energy security , emission problems some developing countries are trying to use alternate fuels for their vehicles

LIQUID FUELS:

Liquid fuels are preferred for IC engines because they are easy to store and have reasonably good calorific value. The main alternative is the alcohol .

ALCOHOL:

Alcohols are attractive alternate fuels because they can be obtained from both natural and manufactured sources. Methanol and ethanol are two kinds of alcohols that seem most promising.

E85

E85 is an alcohol fuel mixture of 85% ethanol and 15% gasoline, by volume. Ethanol derived from crops (bioethanol) is a biofuel.It as a fuel is widely used in Sweden and is becoming increasingly common in the United States, mainly in the Midwest where corn is a major crop and is the primary source material for ethanol fuel production.

E85 is usually used in engines modified to accept higher concentrations of ethanol. Such flexible-fuel engines are designed to run on any mixture of gasoline or ethanol with up to 85% ethanol by volume.

HOW IS IT MADE NOW?

HISTORICALLY MADE FROM CORN AND OTHER STARCH SOURCES OR FROM NATURAL SUGARS BY FERMENTATION

COMMON SOURCES INCLUDE RICE, POTATO, CASSAVA – PLUS CORN AND OTHER GRAINS

MANUFACTURING PROCESS WAS VERY ENERGY-INTENSIVE, BUT IS NOW LESS SO IN MOST MODERN PLANTS, DUE TO ADVANCES IN DISTILLATION TECHNOLOGY

Ethanol

Closed carbon dioxide greenhouse gas cycle for biofuels.Ethanol & biodiesel are sustainable forms of solar energy.

What about Using Ethanol for Fuel?

BLENDING

Automobile fuels are “oxygenated” in order to reduce air pollution. In addition, removal of lead from gasoline renewed interest in ethanol as octane

booster. While E10/E15 is intended for all automobiles, a blend called “E85” is intended

for flex fuel vehicles. E85 can be as high as 30% gasoline in cold climates in winter . The principle reason for blending some gasoline into ethanol for flex fuel vehicles is to improve cold cranking in cold weather.

Ethanol is separated from the water in which it is produced via a process called distillation. The distillation process does not remove all of the water. Having some water mixed in with the fuel is actually improves performance of an internal combustion engine, as the water provides extra mass to absorb the heat of combustion and turn it into high pressure steam for mechanical energy.

However, water and gasoline don’t mix well , so the water must be removed when producing ethanol-gasoline blends.

Power Making Fuel Characteristics

1.Octane Rating [MON]2.Burning Rate3.Latent Heat of Vaporization [kJ/kg]4.Energy Value [MJ/kg]

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1. Octane rating Octane rating is a standard measure of the

performance of an engine . Three common octane ratings for motor fuels: Research Octane Number (RON) Motor Octane Number (MON) (R+M/2) method



MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, higher engine speed, and variable ignition timing to further stress the fuel's knock resistance.

(R+M/2) is the average of the RON and the MON, called the Anti-Knock Index

RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane and n-heptane.

2. Burning Rate The speed at which fuel burns and releases

its heat energy There is less time for fuel to burn at high

RPM’s, so rapid burning fuel is a must in racing

Peak horsepower (kW) and engine efficiency are realized if fuel is almost completely burned by 20 degrees after Top Dead Center (TDC)


3. Latent Heat of Vaporization

a)Measures a fuel’s ability to cool the intake charge and combustion chamber

b)Measured in kJ/ lt. c)Higher rated fuels remove heat better


E85 promotes better cooling: Making the intake charge more dense,

thereby packing more energy (per volume) into the engine

Helping to control detonation Reducing temperatures in the engine

and oiling system components


4. Energy ValueThe total heat energy contained in a given

amount of fuel – kJ/kg Horsepower generation depends on “Net

Energy Value” - Equal to the energy value multiplied by the amount of fuel that can be burned

A fuel’s “stoichiometric” defines its ideal air/fuel ratio

Lower stoichiometric fuels allow more fuel to be burned which, in turn, increases the Net Energy Value of the fuel


Ethanol and Flexible Fuel Vehicles (FFVs)

What is a FFV?

• FFVs are specially designed to run on all ethanol blends up to 85%

• FFVs can use any mixture of gasoline or E85

• FFVs have fuel sensors which monitor ethanol/gasoline ratios

Flexible Fuel Vehicle Flexible Fuel Vehicles, also known as FFVs, are designed to run

on gasoline, E85, or any combination of the two. The “Flexible” nature of the vehicle gives the driver the flexibility to switch back and forth between gasoline and E85.

Ethanol contains more oxygen than gasoline. The vehicles come equipped with an oxygen sensor which determines the amount of ethanol in the fuel at any time. It provides this information to the onboard computer, which then adjusts the engine to maximize efficiency and performance. The fuel may contain anywhere from zero to 85% ethanol. FFVs are widely available and include sedans, minivans, SUVs, and pickup trucks.

Utilization of Alcohol Fuels in Compression Ignition engines

difficulties encountered:- 1.More alcohol fuel than diesel fuel is required by mass

and volume. 2.Large percentages of alcohol do not mix with diesel

fuel, hence use of diesel-alcohol blends is not feasible . 3.Alcohols have extremely low cetane numbers,

whereas the diesel engine is known to prefer 4.Diesel fuels serve as lubricants for diesel engine.

Alcohol fuels do not have the same lubricating qualities.

5. The poor auto-ignition capability of alcohols is responsible for severe knock due to rapid burning of vaporized alcohol.

Alcohol Fumigation Fumigation is a method by which alcohol is

introduced into the engine by carbureting, vaporizing or injecting the alcohol into the

intake air stream. This requires the addition of a carburetor, vaporizer or injector, along with a separate fuel tank, lines and controls.

Fumigation has some following advantages: It requires a minimum of modification to the engine. The engine can switch from dual fuel to diesel fuel operation and vice-

versa by disconnection and connection of the alcohol source to the injector.

If an engine is limited in power output due to smoke emissions, fumigated ethanol could increase the power output because alcohol tends to reduce smoke. This is because of good mixing of the injected charge with alcohol.

Fumigation can substitute alcohol for diesel fuel. Up to 50% of the fuel energy can be derived from alcohol by fumigation

It is a high octane fuel with anti-knock index numbers of over 100.Engines using high octane fuel can run more efficiently by using higher compression ratios. Alcohols have higher flame speed.

It produces less overall emissions compared to gasoline.

When alcohols are burned, it forms more moles of exhaust gases, which gives higher pressure and more power in the expansion stroke.

It has high latent heat of vaporization which results in a cooler intake process. This raises the volumetric efficiency of the engine and reduces the required work input in the compression stroke.

Alcohols have low sulphur content in the fuel.

Reduced petroleum imports and transportation.

ADVANTAGES:

Alcohols have low energy content or in other words the calorific value of the fuel is less.

With equal thermal efficiency and similar engine output usage, twice as much fuel would have to be purchased.

Even with the low energy content of the fuel, engine power for a given displacement would be about the same. This is because of the lower air-fuel ratio needed by alcohol.

Alcohol contains oxygen and thus requires less air for stoichiometric combustion. More fuel can be burned with the same amount of air.

Alcohol is much more corrosive than gasoline on copper, brass, aluminum, rubber, and many plastics. This puts some restrictions on the design and manufacturing of engines to be used with this fuel. Methanol is very corrosive on metals.

It has poor cold weather starting characteristics due to low vapor pressure and evaporation.(E85 rectifies it)

DISADVANTAGES:

Extensive research and development is difficult to justify until the fuels are accepted as viable for large numbers of engines.

Most alternate fuels are very costly at present since the quantity used is very less.

There is lack of distribution points (service stations) where fuel is available to the public.

DIFFICULTIES

CONCLUSIONI Would sum up the whole presentation into few lines saying that reducing fossil fuels in the near future would be a great loss to mankind if we are not able to find out any alternative for it and I found alcohol to be effective as it can be produced easily and the flexible fuel vehicle will be proved to be of great advantage.

THANK YOU

Engineering

Alchol As an alternative fuel for S.I ENGINE