Deck 10: Engine Cooling, Efficiency, and Emissions

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

Answer 1

higher working temperature compared to water cooling

Question 2

Which is more viscous lib oil

A)SEA 30
B)SAE 40
C)SAE 50
D)SAE 80.

Answer 2

SAE 80.

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

Answer 3

a vacuum chamber

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

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

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

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

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%

Question 9

The best method of measuring speed is by

A)mechanical tachometer
B)electrical tachometer
C)magnetic pickup
D)none of the above

Question 10

Flame ionization detector is used for measuring

A)CO
B)HC
C)NO_x
D)CO₂

Question 11

Chemilumine scence analyzer is used for measuring

A)NO_x
B)CO
C)HC
D)CO₂

Question 12

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

A)NO
B)HC
C)CO
D)CO₂

Question 13

Thermal efficiency varies

A)inversely as sfc
B)directly as sfc
C)as square as sfc
D)as root as sfc

Question 14

Mechanical efficiency is ratio of

A)fp to bp
B)fp to ip
C)bp to ip
D)ip to fp

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

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

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

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

Question 19

Indicated power is directly proportional to

A)torque
B)air consumption
C)cylinder peak pressure
D)none of the above

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

Question 21

Brake thermal efficiency of SI engine is in the range

A)35% to 60%
B)25% to 35%
C)60% to 80%
D)none of the above

Question 22

The volumetric efficiency of a well-designed engine is in the range

A)30 to 40%
B)40 to 609%
C)60 to 70%
D)75 to 90%

Question 23

The major contributor of Carbon monoxide is

A)Motor vehicle
B)Industrial processes
C)Stationary fuel combustion
D)None of the above

Question 24

Maximum allowable hydrocarbon in the car emission are approximately

A)10 ppm
B)100 ppm
C)1000 ppm
D)5000 ppm