Delay Period

·         ___________ is the time immediately following injection of the fuel during which the ignition process is being initiated and the pressure does not rise beyond the value it would have due to compression of air.

Answer: Delay period is defined as the time immediately following injection of the fuel during which the ignition process is being initiated and the pressure does not rise beyond the value it would have due to compression of air.

·         The ___________ extends for about 13º, movement of the crank.

Answer: delay period

·         The time for which delay period occurs decreases with ___________ in engine speed.

Answer: increases

·         Delay period serves a useful purpose in that it allows the fuel jet to penetrate well into the combustion space.

Answer: True

·         If the delay is too short the amount of fuel available for simultaneous explosion is too great and the resulting pressure rise is too rapid.

Answer: No, in fact, if the delay is too long the amount of fuel available for simultaneous explosion is too great and the resulting pressure rise is too rapid.

·         The delay period depends upon temperature and pressure in the cylinder at the time of injection.

Answer: True

·         The delay period ___________ with load.

Answer: Delay period is directly proportional to load, so the delay period increases with load.

·         The delay period depends upon nature of the fuel mixture strength.

Answer: True

·         Higher cetane number means a ___________ delay period and smoother engine operation.

Answer: higher

·         Increase in compression ratio ___________ delay period.

Answer: Compression ratio is indirectly proportional to delay period, so increase in compression ratio reduces delay period.

·         At constant speed, delay period is proportional to the delay angle.

Answer: True

·         A pre-combustion chamber gives shorter delay compared to an open type of combustion chamber.

Answer: True