Internal Combustion Engines
Fuel consumption of diesel engines is not guaranteed at one quarter load because at such low loads

The engine is rarely operated
The friction is unpredictable
The small difference in cooling water temperature or in internal friction has a disproportionate effect
The friction is high

ANSWER DOWNLOAD EXAMIANS APP

Internal Combustion Engines
The fuel valve in a four stroke cycle diesel engine

Opens at 15° after top dead center and closes at 20° before bottom dead center
Opens at 15° before top dead center and closes at 20° after top dead center
May open and close anywhere
Opens at top dead center and closes at bottom dead center

ANSWER DOWNLOAD EXAMIANS APP