Question 1

Limitations of air cooling systems are
A)applicable only to large engines
B)cooling is fast
C)higher working temperature compared to water cooling
D)all of the above

Accepted Answer

Air cooling systems generally result in higher working temperatures compared to water cooling systems because air has a lower heat capacity and density than water, making it less efficient at removing heat from the engine.

Question 2

Which is more viscous lib oil
A)SEA 30
B)SAE 40
C)SAE 50
D)SAE 80.

Accepted Answer

SAE 80 is more viscous than the other options, as higher SAE numbers indicate thicker oils.

Question 3

In a naturally aspirated diesel engine, the air is supplied by
A)a supercharger
B)a centrifugal blower
C)a vacuum chamber
D)an injection tube

Accepted Answer

In a naturally aspirated diesel engine, air is drawn into the engine cylinders by the vacuum created during the intake stroke, without the aid of any external devices like superchargers or blowers.

Question 4

The measurement of frictional power by Willans line is applicable only to
A)SI engines at a particular speed
B)CI engines at a particular speed
C)any engine at a particular speed only
D)none of the above

Accepted Answer

The answer of The measurement of frictional power by Willans...

Question 5

Morse test is applicable only to
A)single cylinder SI engines
B)single cylinder CI engines
C)multicylinder CI engines
D)single and multicylinder SI and CI engines

Accepted Answer

The Morse test is used to determine the indicated power of each cylinder in a multicylinder engine, typically applied to multicylinder CI (compression ignition) engines.

Question 6

The most accurate method of determining fp is by
A)Willan's line
B)Morse test
C)measurement of brake and indicated power
D)motoring test

Accepted Answer

The most accurate method of determining friction power (fp) is by measuring both the brake power (output power) and the indicated power (total power developed inside the engine). The difference between these two gives the friction power.

Question 7

In the air bO_x method of measuring air flow, the air box is provided to A)have constant temperature B)have constant flow C)damp out the pulsations D)provide constant velocity of flow

Accepted Answer

The air box in the bO_x method of measuring air flow is provided to damp out the pulsations, ensuring a smoother flow for more accurate measurement.

Question 8

The air box/swept volume ratio should be in the range for single-cylinder engines
A)10- 100%
B)200-300%
C)500 600%
D)> 1000%

Accepted Answer

The air box/swept volume ratio for single-cylinder engines is typically in the range of 500-600% to ensure adequate air supply for combustion.

Question 9

The best method of measuring speed is by
A)mechanical tachometer
B)electrical tachometer
C)magnetic pickup
D)none of the above

Accepted Answer

Magnetic pickup is often considered the best method for measuring speed because it provides accurate and reliable measurements without direct contact with the moving part.

Question 10

Flame ionization detector is used for measuring A)CO B)HC C)NO_x D)CO₂

Accepted Answer

The flame ionization detector (FID) is primarily used for measuring hydrocarbons (HC) in gas chromatography. It is sensitive to compounds that can be ionized in a hydrogen flame, which typically includes most organic compounds, hence its application in detecting hydrocarbons.

Question 11

Chemilumine scence analyzer is used for measuring A)NO_x B)CO C)HC D)CO₂

Accepted Answer

Chemiluminescence analyzers are specifically used for measuring nitrogen oxides (NOx) in emissions, as they detect the light emitted during the reaction of NO with ozone.

Question 12

Non-dispersive infra-red analyzer is widely accepted instrument for measuring A)NO B)HC C)CO D)CO₂

Accepted Answer

Non-dispersive infrared (NDIR) analyzers are widely accepted and used for measuring carbon monoxide (CO) concentrations. They work by detecting the specific wavelength of infrared light absorbed by CO molecules.

Question 13

Thermal efficiency varies
A)inversely as sfc
B)directly as sfc
C)as square as sfc
D)as root as sfc

Accepted Answer

Thermal efficiency varies inversely as specific fuel consumption (sfc). This means that as the sfc decreases (improving fuel efficiency), the thermal efficiency of an engine increases.

Question 14

Mechanical efficiency is ratio of
A)fp to bp
B)fp to ip
C)bp to ip
D)ip to fp

Accepted Answer

Mechanical efficiency is the ratio of brake power (bp) to indicated power (ip), which measures how effectively an engine converts the power generated within the engine into useful work output.

Question 15

For N is the rpm, number of power strokes per minute in a four-stroke engine is
A)2N
B)N/2
C)N
D)4N

Accepted Answer

In a four-stroke engine, there is one power stroke for every two revolutions of the crankshaft, so the number of power strokes per minute is N/2.

Question 16

If N is the rpm, number of power strokes per minute in a two-stroke engine is
A)N
B)2N
C)N/2
D)4N

Accepted Answer

In a two-stroke engine, there is one power stroke for every revolution of the crankshaft, so the number of power strokes per minute is equal to the rpm (N).

Question 17

The spark timing and combustion rate should be such that
A)peak pressure occurs at TDC
B)one half of the total pressure occurs at TDC
C)ignition delay is reduced
D)none of the above

Accepted Answer

The answer of The spark timing and combustion rate should...

Question 18

Volumetric efficiency is a measure of
A)speed of the engine
B)power of the engine
C)breathing capacity of the engine
D)pressure rise in the cylinder

Accepted Answer

Volumetric efficiency is a measure of the breathing capacity of the engine, indicating how effectively the engine fills its displacement volume with air during the intake process.

Question 19

Indicated power is directly proportional to
A)torque
B)air consumption
C)cylinder peak pressure
D)none of the above

Accepted Answer

The answer of Indicated power is directly proportional to
A)torque
B)air consumption
C)cylinder...

Question 20

Turbocharger engines are those in which charge density is increased by
A)separate air compressors
B)compressors driven by exhaust gas turbine
C)cooling inlet air
D)none of the above

Accepted Answer

Turbocharger engines increase charge density by using compressors that are driven by exhaust gas turbines. This process recycles exhaust gases to boost engine power and efficiency.

Quiz 10: Engine Cooling, Efficiency, and Emissions

Limitations of air cooling systems are

Which is more viscous lib oil

In a naturally aspirated diesel engine, the air is supplied by

The measurement of frictional power by Willans line is applicable only to

Morse test is applicable only to

The most accurate method of determining fp is by

In the air bOx method of measuring air flow, the air box is provided to

The air box/swept volume ratio should be in the range for single-cylinder engines

The best method of measuring speed is by

Flame ionization detector is used for measuring

Chemilumine scence analyzer is used for measuring

Non-dispersive infra-red analyzer is widely accepted instrument for measuring

Thermal efficiency varies

Mechanical efficiency is ratio of

For N is the rpm, number of power strokes per minute in a four-stroke engine is

If N is the rpm, number of power strokes per minute in a two-stroke engine is

The spark timing and combustion rate should be such that

Volumetric efficiency is a measure of

Indicated power is directly proportional to

Turbocharger engines are those in which charge density is increased by

In the air bO_x method of measuring air flow, the air box is provided to