Mechanical Engineering - Thermodynamics - Discussion
Discussion Forum : Thermodynamics - Section 1 (Q.No. 17)
17.
The efficiency of Diesel cycle approaches to Otto cycle efficiency when
Discussion:
41 comments Page 4 of 5.
Islam gamal said:
7 years ago
The efficiency will be lower if cutoff ratio is higher because the piston has already moved far down while the heat is still being added.
Brajesh said:
7 years ago
When the cutoff ratio ρ=1 then the efficiency of 'DUAL' cycle becomes efficiency of the Otto cycle.
And when ρ=0 then the efficiency of 'diesel' cycle becomes efficiency of the Otto cycle by L hospital's rule.
And when ρ=0 then the efficiency of 'diesel' cycle becomes efficiency of the Otto cycle by L hospital's rule.
Aniruddh said:
7 years ago
The question should be a Dual cycle, not the diesel cycle.
Because in the dual cycle there are two heat addition one at constant volume and other at constant pressure known as cut off and when this cutoff is made zero the cycle becomes Otto cycle.
Because in the dual cycle there are two heat addition one at constant volume and other at constant pressure known as cut off and when this cutoff is made zero the cycle becomes Otto cycle.
Satish ahir said:
7 years ago
Answer is C.
Because of the value of the cut-off ratio is ZERO put the value in equation of diesel cycle then both are equal.
Because of the value of the cut-off ratio is ZERO put the value in equation of diesel cycle then both are equal.
Madan said:
5 years ago
The answer is right.
Because here (Cut-off) is mention so, when cut-off will be zero then efficiency of diesel cycle approaches to efficiency of otto.
Mind it, CUT-OFF and CUT-OFF RATIO both are different, If cut-off ratio is unity then efficiency of diesel cycle will approaches to efficiency of otto cycle.
By L-HOSPITAL rule, you can prove, but for cut-off ratio.
Because here (Cut-off) is mention so, when cut-off will be zero then efficiency of diesel cycle approaches to efficiency of otto.
Mind it, CUT-OFF and CUT-OFF RATIO both are different, If cut-off ratio is unity then efficiency of diesel cycle will approaches to efficiency of otto cycle.
By L-HOSPITAL rule, you can prove, but for cut-off ratio.
Nilesh said:
5 years ago
Correct, Thanks @Madan.
Vinay said:
5 years ago
The answer is right.
Because here (Cut-off) is mention so, when cut-off will be zero then the efficiency of diesel cycle approaches to the efficiency of otto.
Where CUT-OFF and CUT-OFF RATIO both are different, If cut-off ratio is unity then the efficiency of the diesel cycle will approach to efficiency of otto cycle.
By L-HOSPITAL rule, you can prove, but for cut-off ratio.
Because here (Cut-off) is mention so, when cut-off will be zero then the efficiency of diesel cycle approaches to the efficiency of otto.
Where CUT-OFF and CUT-OFF RATIO both are different, If cut-off ratio is unity then the efficiency of the diesel cycle will approach to efficiency of otto cycle.
By L-HOSPITAL rule, you can prove, but for cut-off ratio.
(1)
Jithin said:
5 years ago
When cut-off is zero OR in other words cut-off ratio is one (i.e. When heat is being added at constant volume), diesel cycle approaches to Otto cycle.
(1)
Trulli said:
5 years ago
If you all compare both the cycle in one PV diagram. The Otto cycle highest temp meet to diesel cycle highest temp when cut off is zero. So the given answer is right.
(1)
Ravindra said:
4 years ago
I think the right answer is B.
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