Which fuel is used in SI engine?

SI engines are commonly fueled on gasoline, with the fuel characterized based on octane number. The octane number defines the fuel’s ability to reduce autoignition or knock, with the higher the octane number, the higher the resistance to autoignition.

Why is petrol gasoline used in SI engine?

In recent times, ethanol has been commonly used as a fuel additive or an alternative fuel in spark ignition (SI) engines and compression-ignition (diesel) engines. The use of ethanol, particularly in SI engines, has become attractive due to its relatively high octane number and the fact that it burns clean [4,5].

Which of the following is the best fuel for SI engine?

Explanation: For C.I. engines fuel most preferred are paraffins and for S.I. engines fuel most preferred are aromatics.

What is the function of spark plug in SI engine?

Your spark plugs are what supply the spark that ignites the air/fuel mixture, creating the explosion which makes your engine produce power. These small but simple plugs create an arc of electricity across two leads which are not touching, but close enough together that electricity can jump the gap between them.

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What are the main characteristics of SI engine fuel?


  • It should readily mix with air to make a uniform mixture at inlet, ie. …
  • It must be knock resistant.
  • It should not pre-ignite easily.
  • It should not tend to decrease the volumetric efficiency of the engine.
  • It should not form gum and varnish.

Which fuel is not suitable for SI engine?

Acetylene increases the poor combustion limit in partial loads in SI engines. The engine can be operated in leaner conditions with gasoline-acetylene mixtures. As seen in Figures 4 and 5 the brake thermal efficiency of the engine increases and the specific fuel consumption decreases.

What is the full form of SI engine?

A spark-ignition engine (SI engine) is an internal combustion engine, generally a petrol engine, where the combustion process of the air-fuel mixture is ignited by a spark from a spark plug.

Which is more efficient SI or CI engine?

CI engines have higher Thermodynamic Efficiency

With a higher compression ratio in CI engines as compared to SI engines, CI engines have a higher thermodynamic efficiency since more work is done with each expansion stroke.

What is the meaning of SI and CI?

CI > SI. Simple Interest (SI) = (P×R×T)/100. CI = Principal (1+Rate/100)n – principal.

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