Which engine is more efficient CI or SI?
Well, if you are referring to efficiency by saying specific output then CI engines have a better energy conversion than SI engines. … Diesel engines compared to petrol engines have a longer stroke length which gives the air-fuel mixture just enough time to burn evenly as well.
What is a CI engine?
A CI engine is an engine in which the fuel charge is ignited by the heat of compression. The process of combustion in the CI engine is fundamentally different from that in a spark-ignition engine.
Why are petrol engines called spark ignition engines?
Spark plugs are used to ignite the air fuel mixture. That's why petrol engines are called spark ignition or si engines. … Mixture of air and petrol enters into the combustion chamber. The piston compresses this mixture ( after, when both the valves are closed).
Why are CI engines more efficient?
When the fuel is injected into the compressed air, it ignites without a spark plug. Because the air is so compressed, the engine gets greater efficiency from the fuel. This means a diesel engine is generally 20 per cent more efficient than an equivalent petrol engine.