In a diesel engine the duration between the time of injection and time of ignition is called

Explanation:

Delay period (Ignition lag):

• Ignition delay period is the time the first drop of fuel enters the chamber to the point when the first flame is observed in the spray.
• It is also defined as the period between the start of injection and the start of ignition.

What does the delay period consist and how it changes:

• It consists of (a) physical delay where atomization, vapourization, and mixing of fuel-air occurs.
• It also consists of (b) chemical delay which is related to pre-combustion reactions
• It depends on

(a) Air inlet pressure and temperature

(b) Compression ratio

(c) Fuel injection pressure

(d) Fuel cetane number

(e) Air Fuel ration

(f) Engine speed and size

Why determining the Delay period is essential:

• To reduce NOx in modern engines, the ignition period is kept minimum.
• Ignition delay is significant to avoid conditions like knocking and power loss due to late peak generation.