Vit
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- Words: 230
- Pages: 9
•
Fuel Pump Problems:
•
Wear / seizure of plunger and barrel
•
caused due to presence of water, abrasive particles such as catalyst fines in fuel
•
severe wear will lead to loss of power due to leakage,
•
causing less amount fuel injected in the cylinder
•
Leaky valves
•
Sticky fuel racks, particularly after prolonged
•
operation at constant load
•
Fuel leakage into camshaft space
•
Variable Injection Timing:
•
VIT is a form of fuel pump control
•
It enables an engine to operate at designed Pmax from 75% to MCR output power
•
Which improves thermal efficiency and gives better fuel economy during part load
•
As the fuel consumption at any load depends on expansion ratio, increase in expansion ratio (due to VIT) improves SFC
•
VIT allows to adjust fuel quality setting (FQS) within 20
•
VIT should not be used to compensate worn cylinder components
• •
Fuel Pump Maintenance Overhauling of pump barrel & plunger by grinding as matched pair
•
Defective unit with scratch & corrosion marks and seized in extreme case must be discarded
•
Overhauling of pump valves by grinding on the seats
•
Check for any damage and replace accordingly
•
All seals and O-rings must be replaced
•
After each overhauling timing must be checked and adjusted if indicator card shows early / late injection
Fuel Pump Problems:
•
Wear / seizure of plunger and barrel
•
caused due to presence of water, abrasive particles such as catalyst fines in fuel
•
severe wear will lead to loss of power due to leakage,
•
causing less amount fuel injected in the cylinder
•
Leaky valves
•
Sticky fuel racks, particularly after prolonged
•
operation at constant load
•
Fuel leakage into camshaft space
•
Variable Injection Timing:
•
VIT is a form of fuel pump control
•
It enables an engine to operate at designed Pmax from 75% to MCR output power
•
Which improves thermal efficiency and gives better fuel economy during part load
•
As the fuel consumption at any load depends on expansion ratio, increase in expansion ratio (due to VIT) improves SFC
•
VIT allows to adjust fuel quality setting (FQS) within 20
•
VIT should not be used to compensate worn cylinder components
• •
Fuel Pump Maintenance Overhauling of pump barrel & plunger by grinding as matched pair
•
Defective unit with scratch & corrosion marks and seized in extreme case must be discarded
•
Overhauling of pump valves by grinding on the seats
•
Check for any damage and replace accordingly
•
All seals and O-rings must be replaced
•
After each overhauling timing must be checked and adjusted if indicator card shows early / late injection
