Mechanical Engineering - Thermodynamics - Discussion

Discussion Forum : Thermodynamics - Section 2 (Q.No. 36)
36.
Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because in Otto cycle
combustion is at constant volume
expansion and compression are isentropic
maximum temperature is higher
heat rejection is lower
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
14 comments Page 1 of 2.

Love said:   1 decade ago
Since rejection of heat takes place at lower temperatures, comparing its equation with carnot cycle, the efficiency is more as in diesel engines rejection of heat takes place at higher temp. than otto cycle.

Navaneeth said:   1 decade ago
According to question Otto cycle is efficient, but practically diesel has more comparison ratio, so it has more efficiency.

Mayank said:   9 years ago
Yes, I agree with you @Navaneeth.

Prince said:   9 years ago
I think the answer should be C because max temperature is higher in otto cycle than the Diesel cycle keeping the compression ratio same and also we could not say anything about temperature if we, please comment to know about it.

ABHISHEK said:   8 years ago
D is the correct option. I agree with it.

Anil sahu said:   8 years ago
No, the correct answer is option 'c'.

Saurabh said:   7 years ago
I agree @Prince. If we plot PV diagram- we see for same compression ratio the maximum temperature achieved by the Otto cycle is higher than that of diesel cycle. Also, there is no such difference can be determined unless it is not given in case of cont Volume heat rejection.

Saurabh said:   7 years ago
I agree @Prince.

If we plot PV diagram- we see for same compression ratio the maximum temperature achieved by the Otto cycle is higher than that of diesel cycle. Also, there is no such difference can be determined unless it is not given in case of cont Volume heat rejection.

Saurabh said:   7 years ago
I agree @Prince.

If we plot pv diagram- we see for same compression ratio the maximum temperature achieved by the Otto cycle is higher than that of diesel cycle. Also, there is no such difference can be determined unless it is not given in case of cont Volume heat rejection.

Dhrupat said:   7 years ago
@Prince.

As we know about petrol. It has a lower flash point, so there is a low temperature at heat addition time. The given answer is correct.


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