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Diff between si and ci

rename
anandengg's version from 2018-12-26 01:28

Section

S.no
Parameter
SI Engine
CI Engine
1.
Definition
It is an engine in which the spark is used to burn the fuel.
It is and engine in which heat of compressed air is used to burn the fuel.
2.
Fuel used
Petrol is used as fuel.
Diesel is used as fuel.
3.
Operating cycle
It operates on Otto cycle.
It operates on Diesel cycle.
4.
Compression ratio
Low compression ratio.
High compression ratio.
5.
Thermal efficiency
High thermal efficiency.
Less thermal efficiency.
6.
Method of ignition
Spark plug is used to produce spark for the ignition.
Heat of compressed air is used for the ignition.
7.
Engine Speed
High speed engines.
Low speed engines.
8.
Pressure generated
Low pressure is generated after combustion.
High pressure is generated
after combustion.
9.
Constant parameter during cycle
Constant volume cycle.
Constant pressure cycle.
10.
Intake
Air + fuel.
Only air.
Weight of engine
Si engine has less weight.
CI engine are heavier.
12.
Noise production
It produces less noise.
It produces more noise.
13.
Production of hydrocarbon
Less Hydrocarbon is produced.
More hydrocarbon is produced.
14.
Starting
Starting of SI engine is easy.
Starting of CI engine is difficult.
15.
Maintenance cost
Low
High
16.
Vibration problem
Less
Very High
17.
Cost of engine
Less cost
High cost
18.
Volume to power ratio
Less
High
19.
Fuel supply
Carburetor
Injector
20.
application
It is used in light commercial vehicles like motorcycle, cars etc.
It is used in heavy duty vehicles likes bus, trucks, ships etc.

 

S.no
Closed Cycle Gas Turbine
Open Cycle Gas Turbine
1.
In this first the air is compressed in the compressor and then heated
in a heating chamber. As the air is heated by an external source, so the amount of the gas remains same.
Here the compressed air is heated in the combustion chamber. So the
products of combustion gets mixed with the heated air and hence the amount of
gas does not remain same.
2.
In closed cycle gas turbine, the gas that comes out from the gas
turbine passes into the cooling chamber.
In open cycle, the gases coming out from the gas turbine is exhausted
in the atmosphere.
3.
The working fluid is circulated continuously.
The working fluid is replaced continuously.
4.
Any other fluid that possesses better thermodynamic properties like helium
can be used.
Here only air can be used as the working fluid.
5.
No earlier wear of the turbine blades, because the enclosed gas does
not gets contaminated while flowing through the heating chamber,
Earlier wear of turbine blades, as the air form the atmosphere enters the
combustion chamber it gets contaminated.
6.
It is best suited for the stationary installation and marine uses
because the air from the turbine is cooled by the circulating water.
It is best suited for the moving vehicle because the air from the
turbine is discharged into the atmosphere.
7.
The maintenance cost of this type of turbine is high.
Its maintenance cost is low.
8.
More mass of installation per kW.
  Less mass of installation per
kW.

 

S.no
Turbocharger
Supercharger
1.
Turbocharger is a forced induction system that compresses the atmospheric gases and sends it to the engine cylinder.
Super charger is also a forced induction system. It compresses the atmospheric
air and sends it to the engine cylinder.
2.
It uses exhaust gases for its energy.
It is connected to the crankshaft of the engine for its energy.
3.
It is not directly connected to the engine.
It is directly connected to the engine through belt.
4.
It has smog altering equipment which helps in lowering the carbon emission.
It doesn’t have wastegate, so the smog emits from the supercharger.
5.
It spins with a speed upto 150000 rpm.
It spins with a speed upto 50000 rpm.
6.
It is much quieter than supercharger.
It is not so quieter.
7.
It is less reliable.
It is more reliable.
8.
Maintenance is not easy.
Maintenance is easy.
9.
Turbocharger delivers their boost better at high rpm.
Supercharger can deliver their boost at lower rpm.
10.
It is more efficient.
It is less efficient.
11.
The compressed air in turbocharger has high temperature.
The compressed air in supercharger has less temperature.
12.
It requires inter-cooler for the compressed air to lower its temperature.
It may or may not require inter-cooler. But in some types, it requires inter-cooler.
13.
It is more complex.
It is less complex.
14.
It has lag problem due to discontinuous supply of energy.
It has negligible lag problem because of continuous supply of energy by crankshaft.
15.
The compressor is rotated by the turbine.
The compressor is rotated by the engine crankshaft through a belt.

 

S.no
Impulse Turbine
Reaction Turbine
1.
In impulse turbine the steam flows through the nozzle and strike on the moving blades.
In the reaction turbine, first the steam flows through the guide mechanism and then flows through the moving blades.
2.
Steam strikes on the buckets with kinetic energy.
The steam glides over the moving blades with both pressure and kinetic energy.
3.
During the flow of steam through moving blades, its pressure remains constant.
During the flow of steam through moving blades its pressure reduces.
4.
The steam may or may not be admitted to the whole circumference.
The steam must be admitted over the whole circumference.
5.
The blades of impulse turbine are symmetrical.
The blades of reaction turbine are not symmetrical.
6.
While gliding over the blades the relative velocity of steam remains constant.
In reaction turbine, while gliding over the blades the relative velocity of steam increases.
7.
For the same power developed, the number of stages required is less.
For the same power developed, the number of stages required is more.
8.
The direction of steam flow is radial to the direction of turbine wheel.
The direction of steam flow is radial and axial to the turbine wheel.
9.
It requires less maintenance work.
It requires more maintenance work.
10.
It is suitable for low discharge.
It is suitable for medium and high discharge.
11.
Pelton Wheel is the example of impulse turbine.
Francis turbine, Kaplan turbine etc. are the examples of reaction
turbine.

 

S.no
NC Machine
CNC Machine
1.
Here NC stands for Numerical Control
CNC stands for Computer Numerical Control.
2.
It is defined as the machine which is controlled by the set of instructions in the form of numbers, letters and symbols. The set of instructions is called as program.
It is defined as the machine which is used to control the motions of the workpiece and tool with the help of prepared program in computer. The program is written in alphanumeric data.
3.
In NC machine the programs are fed into the punch cards.
In CNC machine the programs are fed directly into the computer by a small key board similar to our traditional keyboard.
4.
Modification in the program is difficult.
Modification in the program is very easy.
5.
High skilled operator is required.
Less skilled operator is required.
6.
Cost of the machine is less.
Cost of the CNC machine is high.
7.
Maintenance cost is less
Maintenance cost is high.
8.
The programs in the NC machine cannot be stored.
In CNC machines, the programs can be stored in the computer and can be used again and again.
9.
It offers less flexibility and computational capability.
It offers additional flexibility and computational capability.
10.
  The accuracy is less as compared with the CNC.
It has high accuracy.
11.
It requires more time for the execution of the job.
It takes very less time in the execution of the job.
12.
It is not possible to run it continuously.
It can be run continuously for 24 hours of a day