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Internal Combustion Engines (I.C. Engines) MCQ Questions & Answers | Mechanical Engineering

Learn Internal Combustion Engines (I.C. Engines) MCQ questions & answers are available for a Mechanical Engineering students to clear GATE exams, various technical interview, competitive examination, and another entrance exam. Internal Combustion Engines (I.C. Engines): MCQ question is the important chapter for a Mechanical Engineering and GATE students. Page-5 section-3

Each section contains 100 MCQs on Internal Combustion Engines (I.C. Engines) .
41
The sensing element in the control system of nuclear reactors measures the _________ of the neutron flux in the reactor.
Discuss
Answer & Solution
Answer: Option C
Solution:
The sensing element in the control system of nuclear reactors measures the density of the neutron flux in the reactor.
42
In diesel engine, the compression ratio in comparison to expansion ratio is
Discuss
Answer & Solution
Answer: Option C
Solution:
In diesel engine, the compression ratio in comparison to expansion ratio is More. Compression ratio, in an internal-combustion engine, degree to which the fuel mixture is compressed before ignition. It is defined as the maximum volume of the combustion chamber (with the piston farthest out, or bottom dead centre) divided by the volume with the piston in the full-compression position (with the piston nearest the head of the cylinder, or top dead centre).
43
A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of
Discuss
Answer & Solution
Answer: Option A
Solution:
A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of 75% iso-octane and 25% normal heptane
44
A fuel of cetane number 40 has the same ignition quality as a mixture of
Discuss
Answer & Solution
Answer: Option A
Solution:
A fuel of cetane number 40 has the same ignition quality as a mixture of 40% cetane and 60% alpha methyl naphthalene
45
The term scavenging is generally associated with
Discuss
Answer & Solution
Answer: Option D
Solution:
The term scavenging is generally associated with High efficiency engines. In Automobiles, Scavenging is a process of pushing exhaust gas out of the cylinder and drawing in fresh draught of air or air fuel mixture for the next cycle. The process is essential in having a smooth running of I.C. Engine. If scavenging is incomplete the following stroke will begin with a mix of exhaust fumes rather than clean air. This may be insufficient for poor combustion which leading to poor running condition on an engine. Scavenging is equally important for both 2 Stroke and 4 Stroke Engine. However, it is more difficult to achieve in 2 Stroke engine.
46
The knocking tendency in spark ignition engines may be decreased by
Discuss
Answer & Solution
Answer: Option D
Solution:
The knocking tendency in spark ignition engines may be decreased by Reducing the compression ratio. -A lean mixture reduced the knocking tendency, allowing to operate the CFR engine at higher CCR. -The high concentration of nitrogen in the mixture increased the ignition delay time of the end gas, thus reducing the knocking tendency of the engine.
47
The knocking in diesel engines may be prevented by
Discuss
Answer & Solution
Answer: Option D
Solution:
The knocking in diesel engines may be prevented by - Arrange the fuel injector in such a way that it should start injecting only a small quantity of fuel in starting of the engine. -If we increase the injection pressure, which encourages the atomization of fuel and prevent knock. -by raising the temperature of the coolant that of the intake air as well as the cylinder head and combustion chamber. - Also by increasing the inlet pressure of air (Supercharging), we can prevent diesel knock.