Abnormal Combustion

·         In ____________ combustion, the flame initiated by the spark travels across the combustion chamber in a fairly uniform manner.

Answer: normal

·         In CI engines, abnormal combustion is not a great problem as in SI Engines.

Answer: True

·         ____________ knock occurs when the delay period is excessively long so that there is a large amount of fuel in the cylinder for the simultaneous explosion phase.

Answer: Kerosene

·         The rate of pressure rise per degree of crank angle is then so great that an audible knocking sound occurs.

Answer: True

·         Knock is a function of the fuel chosen and may be avoided by choosing a fuel with characteristics that do not give too long a delay period.

Answer: True

·         If detonation is allowed to persist under extreme conditions or over many engine cycles, engine parts can be damaged or destroyed.

Answer: Yes, detonation leads to the damage of engine parts.

·         Detonation cannot be prevented by reducing peak cylinder pressure.

Answer: In fact, detonation is prevented by reducing peak cylinder pressure.

·         Detonation can be prevented by increasing the manifold pressure by reducing the throttle opening.

Answer: In actual practice, detonation can be prevented by decreasing the manifold pressure by reducing the throttle opening.

·         Knock is less common in ____________ climates.

Answer: Knock is less common in cold climates as compared to hot and moderate climates.

·         Diesel knock is the sound produced by the very rapid rate of pressure rise during the early part of the uncontrolled second phase of combustion.

Answer: True