in S.I engines,ignition process is carried out with the help of a spark plug which ignites a mixture of air and fuel that is compressed in the combustion chamber. Whereas,a diesel engine also known as Compression Ignition (C.I) engine works on the basis of Diesel cycle or Constant pressure heat addition cycle.
What is difference between CI and SI engine?
The Spark Ignition (SI) engine, as its name indicates uses spark to ignite the fuel. … And in Compression Ignition (CI) engine, the air is compressed within the cylinder and the heat of this compression air is used to ignite the fuel.
Which engine is more efficient CI or SI?
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 meant by SI engine?
Definition English: The term spark-ignition engine refers to internal combustion engines, generally petrol engines, where the combustion process of the air-fuel mixture is ignited by a spark from a spark plug.
How ignition takes place in SI and CI?
The combustion in SI engine starts at one point and generated flame at the point of e combustion in SI engine starts at one point and generated flame at the point of ignition propagates through the mixture for burning of the mixture, where as in CI engine, the combustion takes place at number of points simultaneously …
Which fuel is used in SI engine?
In SI engines, acetylene and gasoline are either injected into the intake manifold or directly into the cylinder and the mixture is ignited by spark plug at the end of the compression stroke. In diesel engines, acetylene is either inducted along with intake air or injected directly into the cylinder and compressed.
Which engine is more powerful?
However, Petrol engines are more powerful in the sense that they have a higher acceleration rate due to the higher RPM that the engine can achieve. Given that the torque curve is almost linear, petrol engines achieve peak power at higher RPMs.
What is the most efficient engine?
The new Wärtsilä 31 is the most fuel-efficient four-stroke engine currently available on the market.
Why diesel engines are called CI engines?
Diesel engines are called CI engines because in the diesel engines the combustion of the fuel takes place due to the heat generated by the compression of the air. CI means compression ignition.
How does a CI engine work?
Diesel engines work by compressing only the air. This increases the air temperature inside the cylinder to such a high degree that atomised diesel fuel injected into the combustion chamber ignites spontaneously. … Diesel engines may be designed as either two-stroke or four-stroke cycles.
What are the 3 main engine systems?
- Mechanical fuel injection systems.
- Operating systems.
- Piston rings.
- Primary system.
- Spark ignition systems.
- Spring retainers.
What is the function of spark plug in SI engine?
The spark plug has two primary functions:
To ignite the air/fuel mixture. Electrical energy is transmitted through the spark plug, jumping the gap in the plugs firing end if the voltage supplied to the plug is high enough. This electrical spark ignites the gasoline/air mixture in the combustion chamber.
Which is not related to SI engine?
Which of the following does not relate to spark ignition engine? Explanation: Fuel injector is not related to spark ignition engine as there is no fuel injection in spark ignition engine.
What is delay period in CI engine?
Explanation: Delay period is defined as the time immediately following injection of the fuel during which the ignition process is being initiated and the pressure does not rise beyond the value it would have due to compression of air.
Does flame front exist in CI engine?
In C.I engines, during the suction stroke the air alone is taken in and the fuel is injected over a period of time at the end of the compression stroke. … When the fuel combustion takes place, it happens so, not at a particular point but at several locations resulting in multiple flame fronts.
Why do we not use the same technology to start both Si CI engines?
Answer. Because due to the type of fuel used in each engine!!! In SI engine, petrol has high self ignition point (247–280 C) i.e petrol requires that high temp. to start combustion. It is not possible that the SI engine can’t provide such high temps.