Mechanical Engineering - IC Engines and Nuclear Power Plants - Discussion
Discussion Forum : IC Engines and Nuclear Power Plants - Section 1 (Q.No. 7)
7.
The exhaust valve in a four stroke cycle petrol engine
Discussion:
17 comments Page 1 of 2.
RAJA MUTHU KUMAR said:
4 years ago
The effect of opening the exhaust valve before the piston reaches the BDC results in an overall gain in output. The effect of closing the exhaust valve after TDC is the inertia of the exhaust gases tends to scavenge the cylinder by carrying the maximum amount of gas left in the clearance volume. This will result in increased volumetric efficiency.
(1)
Mohammad Safiq said:
6 years ago
In the Valve timing diagram of the four-stroke engine the last stroke is the exhaust so for the modified valve timing diagram the Valve opens before BDC.
Sid said:
6 years ago
Can anyone explain about this valve timing diagram?
Amit mj said:
7 years ago
But it will cause valve overlap, right?
Swapnil said:
8 years ago
This is to increase volumetric efficiency.
Md.RafiqueAzad said:
8 years ago
Cam profile is 60 degree so if it begins to open 50deg before BDC; it should travel not more than 120deg. i.e exhaust valve should close at 110 deg before TDC.
Vicky said:
9 years ago
How the opening and closing of an imelt valve and exhaust valve depend on the angle? Give reason with proof.
Narayan said:
9 years ago
The exhaust valve is kept open for such prolonged duration in order to let the products of combustion escape from combustion cylinder. This setting is different for light and heavy engines and may also differs with different automakers.
Mahendra bitake said:
9 years ago
It opens before BDC at 20degree & closes after TDC at 10 degree.
Ashish said:
1 decade ago
Exhaust valve opens before 50 degree of BDC and remains open even after completion of exhaust stroke after 20 degree TDC so that it ensures complete removal of flue gaseous from cylinder.
Hence it avoids deterioration of fresh incoming charge during suction stroke which may mix with these burnt gaseous. This time lag of opening and closing of valve is essential during high speed as less time is available for flue gaseous to be thrown away.
Hence it avoids deterioration of fresh incoming charge during suction stroke which may mix with these burnt gaseous. This time lag of opening and closing of valve is essential during high speed as less time is available for flue gaseous to be thrown away.
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