Mechanical Engineering - IC Engines and Nuclear Power Plants - Discussion
Discussion Forum : IC Engines and Nuclear Power Plants - Section 3 (Q.No. 42)
42.
In a petrol engine, the mixture has the lowest pressure at the
Discussion:
10 comments Page 1 of 1.
Virat said:
5 years ago
@Chahat.
The mixture pressure is lowest at end of suction stroke. But the chamber pressure is lowest at beginning of suction.
The mixture pressure is lowest at end of suction stroke. But the chamber pressure is lowest at beginning of suction.
(2)
Ashok Aj said:
8 years ago
Lowest temperature is achieved at beginning of suction stroke.
Lowest pressure is achieved at the end of suction stroke.
Lowest pressure is achieved at the end of suction stroke.
(1)
Vaishnavi said:
6 years ago
I think pressure at beginning of suction stroke = pressure at the end of the suction stroke as per the pv diagram of a petrol engine.
(1)
Chahat sha said:
8 years ago
Can anybody know how?
It should be the begining of suction stroke.
It should be the begining of suction stroke.
Dayma said:
8 years ago
In a petrol engine, only at the end of the suction stroke, the mixture has the lowest pressure.
Mech said:
8 years ago
When the suction stroke starts, the pressure of the mixture is atmospheric pressure. Actually it takes a little fraction of piston movement to create a negative pressure in the cylinder and thereafter this negative pressure is maintained throughout the suction stroke. So when the suction stroke ends the pressure is below atmospheric pressure, as the mixture is inside the cylinder, it will also be at the same pressure as in the cylinder.
Deepak said:
8 years ago
Yes, correct. Agree @Mech.
Pankaj said:
8 years ago
Use the formula PV=mRT as the volume will increase the pressure inside the cylinder will reduce and hence if the volume is less pressure will be more.
Raja said:
6 years ago
If you see the timing of suction, compression, expansion and exhaust strokes in term of degree,
Then, you will see that the suction valve opens 15 degrees before top dead centre which is a high-pressure zone but the suction valve closes at 30 degrees after bottom dead centre which is pretty low-pressure zone.
Hence, the pressure is least at the end of suction stroke.
Then, you will see that the suction valve opens 15 degrees before top dead centre which is a high-pressure zone but the suction valve closes at 30 degrees after bottom dead centre which is pretty low-pressure zone.
Hence, the pressure is least at the end of suction stroke.
Vinay said:
5 years ago
When the suction stroke starts, the pressure of the mixture is atmospheric pressure. Actually it takes a little fraction of piston movement to create a negative pressure in the cylinder and thereafter this negative pressure is maintained throughout the suction stroke. So when the suction stroke ends the pressure is below atmospheric pressure, as the mixture is inside the cylinder, it will also be at the same pressure as in the cylinder.
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