Question

What can we recognize if the color of the exhaust smoke is black?

(a) Overheating of the engine

(b) Loss of power

(c) Unburnt carbon particle

(d) Stalling of the engine

I have been asked this question during a job interview.

I want to ask this question from Petrol Engine Fuel Supply System topic in section Petrol Engine Fuel Supply System of Automotive Engine Design

Answer 1

The correct option is (b) Loss of power

To elaborate: The extra rich mixture when burnt has the colour of the exhaust in black which is caused due to unburnt carbon particles in the exhaust. Whereas the stalling of the engine, unburnt carbon particle and overheating of the engine happens for an extra weak mixture.