Working of I.C.Engine

I.C.Engine working with 4 stroke

In I.C engines there are valves or ports depends on the no. of  working stroke. Here 4-stroke I.C engine.

1. Inlet of Air/Fuel Mixture:
The mixture enters through Intake valve, due to the pressure difference as the pressure  outside the chamber is higher and fluid always flows from high pressure to low pressure. This is called as  Inlet/Suction Stroke. In this stroke, the piston travels from  top to bottom or generally written as from TDC(Top Dead Center) to BDC(Bottom Dead Center).


Also read I.C.Engine most important interview questions


2. Compression:
Now, when the chamber is filled with  mixture, the intake valve gets closed and the piston starts  traveling from BDC-TDC. This Stroke is called as  Compression Stroke. Here in this stroke the mixture is  compressed inside the chamber and hence pressurized  leading to increase in temperature. Both the valves are  kept closed .


3. Ignition/Burning of Fuel: Then it comes to take power out  of the mixture, now the mixture just before the end of  compression stroke is ignited with the help of a spark  plug(only in case of Petrol Engines) provided at the top of chamber which gives spark to the mixture and hence  power is taken from the source. This stroke is known as  Power Stroke.



4. Exhaust: The burned mixture produces flue gasses inside  the chamber and are needed to be removed to repeat the same cycle which is again performed by the principle of  pressure difference. This is called Exhaust stroke and at  this time the exhaust valve is opened to allow the high  pressure flue gasses to move out of chamber.In this way the linear motion of piston  inside the cylinder is converted into rotational motion of  crankshaft connected to it with the help of a connecting  rod.bbsns

 Let's introduction about fundamental definition

5.What is mean by detonation in engine?
It is a tremendously rapid and local increase in pressure which ta upp 10 waves that hit the cylinder walls with such violence that the walls emit a sound like a pig the ping that manifests detonation. Thus a very sudden rise of pressure during combustion a companied by metallie hammer like sound in called detonation.

what is the EFFECT OF ENGINE VARIABLES ON IGNITION LAG  
And:Ignition Iag (the time lag between first ignition of fuel and the commencement of the main phase of combustion) is not a period of inactivity but is a chemical process. 
The ignition lag in terma of erank angles in 10° to 20° and in terms of time, 0.0015 second or so. The duration of ignition lag depends on the following factors :

There are main factor of engine variable of ignition lag

1. Fuel
2. MixtureRatio
3. Intial temperature
4. Pressure
5. Turbulence

 1. Fuel. Ignition lng depends on chemical nature of fuel. The higher the Self Ignition Temperature of fuel, longer the ignition lag. 

2. Mixture ratio. Ignition lag in the smallest for the mixture ratio which gives the maximum temperature. This mixture ratio is somewhat richer than stoichiometric  ratio. 

 3. Initial temperature and pressure. Ignition lag is reduced if the initial temperature- ture and pressure are increased and these can be increased by increasing the compression- nion ratio.

  4. Turbulence. Ignition lag in not much affected by the turbulence.