The clearance in the engine cylinder
A. Increases the mean effective pressure
B. Increases the workdone
C. Decreases the efficiency of the engine
D. All of these
Answer: Option D
Solution (By Examveda Team)
Clearance in the engine cylinder is the volume left between the piston and the cylinder head when the piston is at top dead center.This clearance is essential for mechanical reasons, such as preventing contact between piston and valves.
But increasing this clearance leads to:
✔ Lower Compression Ratio: More clearance means less compression, reducing engine power and efficiency.
✘ Mean Effective Pressure (MEP) does not increase: In fact, it decreases because the combustion gases expand over a larger volume with less pressure buildup.
✘ Work Done does not increase: With a lower pressure due to lower compression, the work output also drops.
✔ Overall, efficiency drops as more heat is wasted and less useful work is obtained.
Thus, only Option C is correct. Options A and B are incorrect, so D (All of these) is wrong.
This Question Belongs to Mechanical Engineering >> Steam Boilers, Engines, Nozzles And Turbines
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Comments (1)
The expansion of steam in a nozzle follows
A. Carnot cycle
B. Rankine cycle
C. Joule cycle
D. Stirling cycle
A. Steam enters and exhausts through the same port
B. Steam enters at one end and exhausts at the centre
C. Steam enters at the centre and exhausts at the other end
D. None of the above
The mechanical draught _________ with the amount of smoke.
A. Increases
B. Decreases
C. Does not effect
D. None of these
A. Higher effectiveness of boiler
B. High calorific value coal being burnt
C. Fouling of heat transfer surfaces
D. Raising of steam temperature
The clearance in the engine cylinder decreases the mean effective pressure, decreases the work done, and decreases the efficiency.
Compression Ratio= Total Cylinder Volume/Clearance Volume