Deck 7: Supercharging and Ignition Timing in Engines

Question 1

Ignition timing is adjusted by

A)tachometer
B)stroboscopic light
C)stop watch
D)accurate clock

Answer 1

stroboscopic light

Question 2

Vacuum advance mechanism shifts the ignition point under

A)no load operation
B)full load operation
C)part load operation
D)under sudden acceleration

Answer 2

part load operation

Question 3

Which of the following statement is wrong?

A)retarded timing causes exhaust gas temperature to be higher
B)retarded timing improves fuel economy
C)retarded timing requires slightly longer throttle opening
D)retarded timing causes burning of the hydrocarbons in the exhaust

Answer 3

retarded timing causes burning of the hydrocarbons in the exhaust

Question 4

Choose the correct statement from the following

A)maintenance problem in magneto-ignition system is more
B)magneto ignition system occupies more space
C)magneto ignition system is used in larger four wheelers
D)magneto ignition system has poor quality of spark during starting

Question 5

Battery ignition system

A)occupies more space
B)has more maintenance problem
C)is commonly employed in four wheelers
D)all of the above

Question 6

Method of governing used in petrol engine is

A)hit and miss governing.
B)quality governing
C)quantity governing
D)none of above

Question 7

Pick up the false statement

A)Thermal efficiency of diesel engine i about 34%
B)Theoretically correct mixture of air am petrol is approximately 15 : 1
C)High speed compression engines operate on dual combustion cycle
D)S.I. engines are quality-governed engines.

Question 8

The centrifugal type supercharger is preferable only for

A)low speeds
B)high speeds
C)high pressures
D)none of the above

Question 9

The advantage of Root's supercharger is

A)big pressure
B)minimum maintenance
C)consumes less power
D)occupies less space

Question 10

Supercharging air compressor is driven by

A)exhaust gas turbine
B)engine itself
C)separate electrical motor
D)none of the above

Question 11

If turbochargers compressor is driven by

A)exhaust gas turbine
B)engine itself
C)separate electrical motor
D)none of the above

Question 12

Cooling after compression is necessary to

A)increase the density of air
B)reduce engine operating temperatures
C)both (a) and (b)
D)increase exhaust temperature

Question 13

Volumetric efficiency of supercharged engine is

A)between 100 - 110%
B)between 90 - 100%
C)between 80 - 90%
D)between 70 - 80%

Question 14

Supercharging is normally done in

A)racing cars
B)marine engines
C)automotive diesel engines
D)none of the above

Question 15

Compared to engine driven supercharger the exhaust driven super charger is

A)easy to handle
B)supplies more air
C)utilizes the exhaust energy of the engine
D)matching with engine is easy

Question 16

Types of supercharger are

A)reciprocating type
B)gear type
C)centrifugal type
D)none of the above

Question 17

The operation of forcing additional air under pressure in the engine cylinder is known as

A)scavenging
B)turbulence
C)supercharging
D)pre-ignition

Question 18

Supercharging is essential in

A)diesel engines
B)gas turbines
C)petrol engines
D)aircraft engines.

Question 19

The output of a diesel engine can be increased without increasing the engine revolution or size in following way

A)feeding more fuel
B)increasing flywheel size
C)heating incoming air
D)supercharging.

Question 20

Supercharging is the process of

A)supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere
B)providing forced cooling air
C)injecting excess fuel for raising more load
D)supplying compressed air to remove combustion products fully

Question 21

Pick up the wrong statement about supercharging

A)supercharging reduces knocking in diesel engines
B)there can be limited supercharging in petrol engines because of detonation
C)supercharging at high altitudes is essential
D)supercharging results in fuel economy

Question 22

The reason for supercharging in any engine is to

A)increase efficiency
B)increase power
C)reduce weight and bulk for a given out-put
D)effect fuel economy

Question 23

For the same power developed in I.C. engines, the cheaper system is

A)naturally aspirated
B)supercharged
C)centrifugal pump
D)turbo charger

Question 24

In SI engines maximum flame speed is obtained when the equivalent ratio is between

A)1.1 and 1.2
B)1.0 and 1.1
C)1.2 and 1.3
D)less than 1

Question 25

In SI engines flame speed increases

A)with turbulence
B)with fuel-air ratio
C)both (a) and (b)
D)none of the above