Question

Lean air-fuel mixture is required for

• A. Idling
• B. Cruising
• C. Starting
• D. Acceleration

Answer 1

The correct option is B

Cruising

Explanation for Correct Option:

Option (B):

1. A lean air-fuel mixture shows that there is more air than the ideal air-fuel ratio.
2. This can be good from the economic point of view and emissions but bad for power.
3. During cruising, the mixture is lean as the emission is controlled by using this ratio.
4. Hence more air is burnt for the equal value of the fuel when operating at standard sea level.
5. These types of weaker mixtures give a good economy when compared to the economy of the rich ratio mixture.

Explanation for Incorrect Option:

Option (A):

1. Idling is nothing but keeping a vehicle at rest while keeping the engine turned on.
2. Hence lean air-fuel mixture is not required for idling.

Option (C):

1. Starting is nothing but turning on the engine of the vehicle so that it can start moving.
2. Hence lean air-fuel mixture is not required for starting.

Option (D):

1. Acceleration is nothing but increasing the speed of the vehicle with respect to time.
2. Hence lean air-fuel mixture is not required for acceleration.

Hence, option B is correct.