26-12-2012, 05:29 PM
FUELS
FUELS.pptx (Size: 1.35 MB / Downloads: 38)
INTRODUCTION
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner.
Types and Properties of Fuels
As in India, diesel and petrol are main fuel types where the main difference is defined by the cost of operating. Today we will discuss about some other fuels along with the conventional type .Which is better for what? And which should I choose?
Though there are alternative fuels like bio-gas and ethanol, we are not dealing in detail as they are not used in practice due to non-availability in sufficient quantity.
Gasoline
A typical gasoline is predominantly a mixture of paraffin's ,naphthenes and olefins
Energy content per kilogram is higher than for gasoline (higher hydrogen to carbon ratio)
The weight-density of gasoline is about 740 kg/m³ (6.175 lb/US gal)
Gasoline contains about 43.2 MJ/L energy content
The CO2 emissions from diesel are 73.38 g/MJ
Octane rating of gasoline is it’s ability to resist Auto-ignition is measured relative to a mixture of 2,2,4-trimethylpentane (an isomer of octane) and n-heptane
Diesel
Density of diesel is about 0.832 kg/l (6.943 lb/US gal), about 12% more than ethanol free petrol (gasoline), which has a density of about 0.745 kg/l (6.217 lb/US gal)
Offers a net heating value of 43.1 MJ/kg as opposed to 43.2 MJ/kg for gasoline
Higher volumetric energy density at 35.86 MJ/l (128 700 BTU/US gal) vs. 32.18 MJ/l (115 500 BTU/US gal) for gasoline
The CO2 emissions from diesel are 73.25 g/MJ, just slightly lower than for gasoline at 73.38 g/MJ
Cetane number for diesel is a measure of the fuel’s delay of ignition time
CNG
Produced by compressing natural gas methane [CH4]), to less than 1% of the volume it occupies at standard atmospheric pressure.
It is stored and distributed in hard containers at a pressure of 200–248 usually in cylindrical or spherical shapes.
Volumetric energy density is estimated to be 42% of LNG's (because it is not liquefied), and 25% of conventional vehicles.
CNG is less likely to auto-ignite on hot surfaces, since it has a high auto-ignition temperature (540 °C) and a narrow range (5%-15%) of flammability.
CNG can be used in Otto-cycle (gasoline) and modified Diesel cycle engines except the design should be altered.
COMPRESSED AIR
Less working temperatures up to only 100 degree Celsius
Carbon or glass fiber tanks can crack easily are used to avoid explosion during accidents where Air is stored at a pressure of 4,351 psi
Priced at $12,700-$15000 can hit 68 mph at a range of 125 miles
Takes just minutes to get refueled
Cost only around $2 to fill the car up with 340 liters of air
0.176 pounds of carbon dioxide emissions per mile compared to 0.40 of I.C engines
ELECTRIC VEHICLE
12g per km CO2 emissions compared to 250g for a conventional vehicle
$5000 - $ 8000 more expensive than an conventional vehicle
Battery consumption cost of US$ 0.1174 per 1 mile (1.6 km)
Top speed of 250 mph and can accelerate from 0 to 60 mph (97 km/h) in 3.7 seconds
On-board efficiency of around 80% compared to 15% of gasoline and 20% of Diesel engines
Vehicle efficiency is typically 24.4 kW·h/100 km
High torque over a larger range of speeds during acceleration because they are function of current, not rotational speed
HYBRID VEHICLE
The types of Hybrids are:
Parallel hybrid
Mild parallel hybrid
Power-split or series-parallel hybrid
Series hybrid
Plug-in hybrid electrical vehicle (PHEV)
HEV has an average mileage rating of 60 mpg/city and 66 mpg/highway
Top speed of 50 to 100 miles from 90 horsepower at 5,700 rpm
The rare earth element dysprosium used in motor parts and Neodymium in high-strength are rare and costly elements
Conclusion
Usually in certain areas either of CNG or LPG is available. Hence, for users, the choice is generally between diesel, petrol or CNG (for North India) or diesel, petrol or LPG (for South India).