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DIFFERENCE BETWEEN S.I AND C.I ENGINES

Criteria S.I. Engine (Petrol or Spark Ignition Engine) C.I. Engine (Diesel or Compression Ignition Engine) Working Cycle Works on Otto Cycle or Constant Volume Cycle. Works on Diesel Cycle. Mixture During Suction Stroke Takes a mixture of air and petrol during the suction stroke. Takes only air during the suction stroke. Fuel Used Uses petrol as fuel. Uses diesel as fuel. Compression Ratio Has a compression ratio that varies from 6 to 10. Has a compression ratio that varies from 16 to 20. Engine Weight and Cost S.I. engines are lighter and cheaper. C.I. engines are heavier and costlier. Initial Cost Initial cost is lower compared to C.I. engines. Initial cost is high due to high compression ratio. Starting Starting is easy. Starting is difficult, especially in cold conditions. ...

POWER TRANSMISSION


Power Transmission

Belt and Rope Drives

When a wrapping connector takes the form of a band with a thickness small in comparison to its width, it is called a belt. When the cross-section of the wrapping connector is circular, it is called a rope.

Types of Belts

Type Description Use
Flat Belt A belt having a rectangular cross-section. It is used for power transmission when the distance between two pulleys is not more than 8 meters. It is mostly used in factories.
V-Belt A belt having a trapezoidal cross-section. It is used for power transmission when two pulleys are close to each other. It is suitable for transmitting large power.
Circular or Rope Belt A belt having a circular cross-section. It is used when the distance between two pulleys is more than 8 meters.

Advantages and Disadvantages of V-Belt Over Flat Belt

Advantages Disadvantages
V-belt transmits more power than a flat belt. It is not suitable for long-distance power transmission.
V-belt requires small adjustments. Construction is complicated.
It has a longer life. V-belts are not durable.
It can be easily installed and removed. It is affected by temperature.
It offers high velocity ratio. Improper belt tension affects the life of the V-belt.
V-belt transmits a large amount of power.




Q-4 Types of belt - derives
1.) Open belt derives :- In this derive, both the shaft are connected parallel and rotate in the same direction. 
The distance between the two parallel shaft not more than 8 meters.

2.) Crossed belt derives :- in this derive, the shaft connected parallel and rotate in opposite direction.



3.) Angular derives :- In this derives , the axes of rotation of the pulleys connected at any angle which may be intersecting or non- intersecting.
When the two Connecting pulleys are at right angle ,it is known as quarter turn derives .


4.) Belt derives with Idler Pulley:- in this derive, one idler pulley added to provide larege velocity ratio in short distance.



5.) Stepped pulley derive :- It is used for changing angular speed of driven shaft, while the angular speed of driving shaft remains constant.

6.) Fast and Losse Pulley derives :- In this derive , two pulleys are mounted on the deriven shaft.
One pulley is keyed on to the shaft it is called fast pulley.
Second pulley runs freely on the shaft it is called loose pulley.
7.) Compund derive:- it is used for large velocity ratio.










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DIFFERENCE BETWEEN S.I AND C.I ENGINES

Criteria S.I. Engine (Petrol or Spark Ignition Engine) C.I. Engine (Diesel or Compression Ignition Engine) Working Cycle Works on Otto Cycle or Constant Volume Cycle. Works on Diesel Cycle. Mixture During Suction Stroke Takes a mixture of air and petrol during the suction stroke. Takes only air during the suction stroke. Fuel Used Uses petrol as fuel. Uses diesel as fuel. Compression Ratio Has a compression ratio that varies from 6 to 10. Has a compression ratio that varies from 16 to 20. Engine Weight and Cost S.I. engines are lighter and cheaper. C.I. engines are heavier and costlier. Initial Cost Initial cost is lower compared to C.I. engines. Initial cost is high due to high compression ratio. Starting Starting is easy. Starting is difficult, especially in cold conditions. ...

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