In spark ignition engines, the knocking tendency can be decreased by ______________

Consider the following statements with regard to IC engines: 1. For best fuel economy of spark ignition engines, the fuel-air mixture should be lean 2. With supercharging, the specific consumption in compression ignition engines increases 3. With increase of load, knocking tendency in compression ignition engines increases Which of the above statements are correct?

A

1 and 2 only

B

2 and 3 only

C

1 and 3 only

D

1, 2 and 3

The advancing of spark timing in spark ignition engines will _________ knocking tendency.

A

Increase

B

Reduce

C

Not effect

D

None of these

Consider the following statements pertaining to supercharging of engines: 1. The power output for a given engine increases 2. The loss of power due to altitude is compensated 3. The increase in supercharging pressure decreases the tendency to detonate in spark ignition engines 4. The mechanical efficiency of supercharged engines is quite high compared to naturally aspirated engines Which of the above statements are correct?

A

1 and 3

B

3 and 2

C

2 and 3

D

1 and 2

The knocking tendency in spark ignition engines can be decreased by adding dopes like tetra ethyl lead and ethylene dibromide.

A

True

B

False

The knocking tendency in spark ignition engines may be decreased by

A

Controlling the air-fuel mixture

B

Controlling the ignition timing

C

Controlling the exhaust temperature

D

Reducing the compression ratio

In order to prevent knocking in spark ignition engines, the charge away from the spark plug should have

A

Low density

B

Low temperature

C

Long ignition delay

D

All of these

With increase in __________ Knocking tendency in a spark ignition petrol engine decreases.

A

Supercharging

B

Wall temperature

C

Compression ratio

D

Engine speed

The knocking in spark ignition engines can be reduced by

A

Retarding the spark

B

Increasing the engine speed

C

Both (A) and (B)

D

None of these

In spark ignition engines knocking can be reduced by:

A

Increasing the compression ratio

B

Increasing the cooling water temperature

C

Retarding the spark advance

D

Increasing the inlet air temperature

In Spark Ignition (SI) engines, the possibility of knocking can be reduced by

A

Increasing compression ratio

B

Decreasing compression ratio

C

Increasing the coolant temperature

D

Advancing the spark timing

In spark ignition engines, the knocking tendency can be decreased by ______________

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