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Mechanical Engineering - IC Engines and Nuclear Power Plants - Discussion

Discussion Forum : IC Engines and Nuclear Power Plants - Section 1 (Q.No. 30)
IC Engines and Nuclear Power Plants
30.
The thermal efficiency of diesel engines is about
15%
30%
50%
70%
Answer: Option
Explanation:

The thermal efficiency of diesel engines is about 30-50%. This means that for every 100 units of fuel energy input, the engine is able to convert 30-50 units of that energy into useful work. The remaining energy is lost as heat or exhaust.

The maximum theoretical efficiency of a diesel engine is about 70%. However, this is rarely achieved in practice due to factors such as friction, heat loss, and incomplete combustion.

Discussion:
36 comments Page 2 of 4.
Nisar said:   7 years ago
It is nearly 35% - 40% for diesel engine.
Nisar said:   7 years ago
It is nearly 35% - 40% for diesel engine.
D.S.GOKUL RAJA said:   7 years ago
It is 30 to 35%.
Er. Rohit said:   7 years ago
The thermal efficiency of the diesel engine varies from 40 to 50 per cent and in petrol 25 to 30 percentage.
Akshay said:   7 years ago
30% is correct.
Raj said:   7 years ago
The maximum efficiency is limited to 30% for SI and 35% for CI engines.
S. Ata said:   8 years ago
Gasoline engines are typically 30% efficient while diesel engines can convert over 45% of the fuel energy into mechanical energy.

But Question asked about themal efficiency not mechanical efficiency. So answer is correct.
Sumit Dubey said:   8 years ago
SI engine thermal efficiency is 26%.

CI engine thermal efficiency is 40%.
Sriram said:   8 years ago
since maximum compression ratio for a diesel engine is 22:1; by considering the thermal efficiency of an Otto cycle.

Efficiency = 1- (1/ CR^(1.4-1)). CR=22 so therefore efficency is 70%.
Rama said:   8 years ago
Efficiency of diesel engine is about 30-35%.
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