Mechanical Engineering - IC Engines and Nuclear Power Plants - Discussion

3. 

In a four stroke cycle, the minimum temperature inside the engine cylinder occurs at the

[A]. beginning of suction stroke
[B]. end of suction stroke
[C]. beginning of exhaust stroke
[D]. end of exhaust stroke

Answer: Option A

Explanation:

No answer description available for this question.

Srini said: (Jan 18, 2013)  
I believe option B is more appropriate, because at the beginning of the suction stroke high temperature exhaust gas had just omitted hence the chamber will be still hot. By the end of suction stroke chamber is filled with fresh air which is atm temp.

Pandian said: (Mar 2, 2013)  
Yes at the end of suction stroke cylinder temp less.

Vsmdi Krishna said: (Jun 28, 2013)  
No the answer which were given is absolutely why because the engine sucked air from the atmosphere so the temperature inside cylinder not varied with atm pressure at suction only the minimum temperature available.

Aditya S Nimje said: (Aug 6, 2013)  
I think B is the correct answer because, end of the suction stroke fresh air will be come in to the cylinder and which decrease the temp.of cylinder.

Manish Yadav said: (Aug 12, 2013)  
I think A is correct because at the beginning of suction stroke volume is less than at end of suction stroke but pressure is same so as per PV=nRT temp. is min. at beginning of suction stroke.

Satish.Eppili said: (Feb 9, 2014)  
I think A is the right. Exhaust gases are exhausted from cylinder so that consist some temp then input enter in to the cylinder at that state cylinder temp will be down and minimum temp is able. Thank you.

Ram said: (May 19, 2014)  
In this question its not completely clarified.

In the starting of engine the option A is right.
Otherwise option B is right.

Nitish said: (Jun 28, 2014)  
We'll the correct answer may seem B, but a closer look gives A.

This is because due to Ram Effect the end of suction stroke is at higher than atmospheric pressure, while beginning of suction stroke is at atmospheric pressure (Pressure drops with further movement of piston). Further volume at end of suction stroke is higher, so a simple application of PV=nRT can reveal the answer.

Pupun said: (Sep 21, 2014)  
At end of the suction process because at that point volume is maximum.

Xyz said: (Dec 29, 2014)  
Just check the T-S diagram for 4 stroke engine.

Nihit said: (Jan 23, 2015)  
I think B because at the starting of suction stroke temp. Of gas is atmosphere and gas expand in the cylinder during movement of piston from TDC to BDC (at the end of suction stroke). So temperature of gas decrease.

Amit said: (Jun 19, 2015)  
Answer A is correct because at beginning of suction the temperature is less. As well as the piston move downward the cylinder surface be contact with air and so that cylinder heat absorbed by air and its temperature increases.

Harsh said: (Jul 11, 2015)  
Option B seems to be more appropriate because the fresh air cools the cylinder and reduces the temperature resulting minimum temperature.

Gaurav Hirani said: (Jul 20, 2015)  
All those who are giving the reason PV=nRT are only taking into consideration P, V and T parameters, also look at n, at the beginning of stroke n is very less and after the completion of suction stroke n will be higher, and since temp is inversely proportional to n we can also say temperature will be higher at beginning and lesser at end of suction stroke.

Segupratheek said: (Jul 26, 2015)  
He tells the minimum temperature means the ends of suction stroke the piston will comes from TDC to BDC. Because of the friction the minimum heat will be generated. The answer is B.

Nikhiljoshte said: (Aug 4, 2015)  
I think answer B is correct. The inside surface area of cylinder is still hot at the beginning of suction some heat will be transfer to the air by convection at the end of suction.

Hari said: (Aug 17, 2015)  
Temperature is less at the end of the suction stroke, as fresh air also takes the cylinder's hotness.

Swasthika Kulamarva said: (Aug 29, 2015)  
I don't think PV=nRT is valid for open systems like engines. It is valid for only closed systems i.e. until inlet and exhaust valves are closed. So, answer is B according to me.

Srinibash said: (Oct 7, 2015)  
A is correct because as suction stroke completes some fresh charge is already in while the cylinder is about to suck.

So its due to the fresh charges that the temperature is minimum.

Sushil Kumar Gupta said: (Nov 11, 2015)  
Option B is correct, because fresh air have low temp than exhaust gases in the cylinder.

Amit Kumar said: (Dec 3, 2015)  
A/C to TS diagram minimum temperature at end of suction.

Prasadkatta said: (Dec 29, 2015)  
I'm not agree to this answer option b is correct because fresh air have low temperature than exhaust gases in the cylinder.

Rajeev Pal said: (Feb 8, 2016)  
This site is awesome.

Hiren Akhaja said: (Apr 16, 2016)  
I think the answer [B] is right. Because at beginning of suction stroke exhaust gases are just delivered and hence temperature must be high and as suction happens atmospheric air comes in contact with engine cylinder and temperature reach it lowest value.

Dalwai said: (Jun 14, 2016)  
Option B is correct because at the beginning of the suction stroke high-temperature exhaust gas had just omitted hence the chamber will be still hot.

By the end of suction stroke chamber is filled with fresh air which is atm temperature.

Bhaskar said: (Jul 10, 2016)  
I think Option B is correct because at the beginning of the suction stroke high-temperature exhaust gas had just omitted.

Hence, the chamber will be still hot. By the end of the suction, stroke chamber is filled with fresh air which is at minimum temperature.

Rajesh Kumar said: (Jul 23, 2016)  
I think, the correct answer is option B.

Ashutosh said: (Aug 26, 2016)  
The question is slightly tricky if you call it that.

It is mentioned 'inside the cylinder' which implies that they are asking about the temperature of the working fluid present inside the cylinder, which is obviously at the lowest temperature at the beginning of suction stoke. Where as if we talk about the cylinder temperature then B is correct after reasonable assumptions.

Aditya Kumar said: (Sep 3, 2016)  
I think the answer [B] is right. Because at beginning of suction stroke exhaust gases are just delivered and hence temperature must be high and as suction happens atmospheric air comes in contact with engine cylinder and temperature reach it lowest value.

Ksk said: (Oct 24, 2016)  
I think B is correct because at the end of the suction stroke the volume increases so the air+ fuel expands.

Yakanth Pediredla said: (Nov 3, 2016)  
Please tell me, which is the final answer?

Yogesh T. said: (Nov 30, 2016)  
I think option A is correct. Because at the beginning of suction stroke air temperature is low. At the end of suction, air temp increase as the air will be in contact with hot cylinder.

Rudra said: (Dec 14, 2016)  
A is the correct answer. Because, the question is given for minimum temp. If it is maximum temp then it option B is correct. Due to piston moves to TDC the pressure increase and temp also increase.

Sidhu said: (Jan 21, 2017)  
In question, the temperature is within the cylinder. It should be at the end of suction.

Karthik .B said: (Feb 9, 2017)  
Here asking about working fluid temperature, not cylinder temp. So, I think option 1 is correct.

Shrinath Yemul said: (Feb 16, 2017)  
A is correct one. As I have checked TS diagram.

Muhammad Waqas said: (Mar 15, 2017)  
Statement is: In a four stroke cycle, the minimum temperature INSIDE THE ENGINE CYLINDER.

Answer: At the end of exhaust the temperature of the cylinder is high. In the beginning of suction stroke the fresh air enters the cylinder (low temperature) and by the end of the suction stroke, the intake fresh air becomes hot (high temperature) why? Because it comes in contact with cylinder wall and gets warm and warm until the suction ends. Also by T-S diagram, it is clearly shown that minimum temperature is at the beginning of the suction stroke. So, the answer is option A.

Raju said: (Jun 26, 2017)  
Answer A is correct.

Hitesh Daka said: (Jun 26, 2017)  
Nice explained @Muhammad Waqas.

Ermias said: (Jul 30, 2017)  
I agree @Muhammad Waqas.

Vishal said: (Aug 8, 2017)  
According to me, option B is correct.

Anil said: (Oct 23, 2017)  
B is the right answer.

Yogi said: (Nov 29, 2017)  
According to Ts diagram beginning temp less in suction stroke.

Kalprajsinh Zala said: (Jun 7, 2018)  
At the Beginning of the suction stroke, everything is hot, the air fuel mix comes in but has a lot of work to do cooling everything down. By the time it has sucked in a whole cylinder of air, the chamber cylinder temperature will be at its lowest point at the bottom of the cycle.

Vin said: (Mar 19, 2019)  
Option B is correct.

Rakesh Banik said: (Jul 2, 2019)  
As per the T-S diagram of 4 stroke engine. Option A is right.

Raghavendra Naik said: (Jul 29, 2019)  
As pv=nrt since at the beginning of suction stroke pressure will be less and volume will be less hence definitely temp will less compare to end of suction stroke because p and v value will be high.

Jitendra Kumar Verma said: (Sep 8, 2019)  
For working fluid temperature is minimum at beginning of suction stroke.

For other things like piston, cylinder head, resedual exhaust gases temperature is minimum at the end of suction stroke.

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