An air lock in a fuel feed system is removed by using which of the following?
Understanding Air Locks in Fuel Feed Systems
An air lock is a common problem that can occur in a fuel feed system. It happens when air gets trapped in the fuel lines, preventing the proper flow of fuel from the fuel tank to the engine. This trapped air creates a blockage, making it difficult or impossible for the fuel pump to deliver fuel effectively, which can prevent the engine from starting or running smoothly.
Why Removing Air Locks is Crucial
For an internal combustion engine to work, it needs a continuous and uninterrupted supply of fuel. Air mixed with fuel, or a blockage caused by air, disrupts the precise fuel-air mixture required for combustion. Therefore, removing any trapped air or 'air lock' from the fuel lines is essential for the system to function correctly.
How to Remove an Air Lock
Removing an air lock typically involves purging the fuel lines to force the trapped air out. This requires a component capable of creating pressure or suction to move the fuel (and the trapped air) through the system until only fuel remains. Let's look at the options provided:
- Electrical fuel pump: This is the main pump responsible for delivering fuel from the tank to the engine during normal operation. While it moves fuel, it might not always be powerful enough on its own to clear a significant air lock, especially if the system has completely run out of fuel and taken in a lot of air.
- Priming pump: A priming pump is specifically designed to manually or electrically draw fuel from the tank and push it through the lines, filling the system and pushing out any air. It is often used after maintenance, running out of fuel, or when an air lock is suspected, to restore the fuel supply to the engine before or during starting. Its primary function is to 'prime' the system, ensuring it's full of fuel and free of air.
- Water pump: A water pump is part of the engine's cooling system. It circulates coolant (usually a mix of water and antifreeze) through the engine to prevent overheating. It has no function in the fuel feed system and cannot remove an air lock from fuel lines.
- Oil pump: An oil pump is part of the engine's lubrication system. It circulates engine oil to reduce friction and wear between moving parts. It is entirely separate from the fuel feed system and cannot remove an air lock from fuel lines.
Based on the functions of these components, the tool specifically used to remove an air lock in a fuel feed system by ensuring the lines are filled with fuel is the priming pump.
Priming Pump Function Explained
The priming pump works by creating suction at the tank end or pressure further down the line, drawing fuel up and through the system. As fuel flows, it displaces the trapped air, pushing it towards the engine or a return line where it can escape. Once the lines are full of fuel, the air lock is removed, and the main fuel pump (if electric) or the injection pump (in diesel systems) can take over for normal operation.
Revision Table: Fuel System Components
| Component | Primary Function | Role in Air Lock Removal |
|---|---|---|
| Electrical Fuel Pump | Delivers fuel during normal operation | May help, but not specifically designed for initial priming/purging large air pockets. |
| Priming Pump | Fills fuel lines and removes air before starting | Specifically designed to remove air locks. |
| Water Pump | Circulates engine coolant | No role in the fuel system. |
| Oil Pump | Circulates engine lubricant | No role in the fuel system. |
Additional Information: Air Lock Causes
Air locks can occur due to several reasons, including:
- Running the fuel tank completely empty.
- Replacing fuel filters or other components in the fuel lines without proper bleeding procedures.
- Loose connections in the fuel lines allowing air to be drawn in.
- Faulty fuel pump or fuel sender unit.
Identifying and addressing the cause is important to prevent recurring air locks. Using the priming pump is the standard method to restore fuel flow after such issues.
Important Questions from Miscellaneous
A stone is thrown horizontally from the top of a 20 m high building with a speed of 12 m/s. It hits the ground at a distance R from the building. Taking g = 10 m/s2 and neglecting air resistance will give :
A sphere of volume V is made of a material with lower density than water. While on Earth, it floats on water with its volume f1V (f1 < 1) submerged. On the other hand, on a spaceship accelerating with acceleration a < g (g is the acceleration due to gravity on Earth) in outer space, its submerged volume in water is f2V. Then:
A railway wagon (open at the top) of mass M1 is moving with speed v1 along a straight track. As a result of rain, after some time it gets partially filled with water so that the mass of the wagon becomes M2 and speed becomes v2. Taking the rain to be falling vertically and the water stationery inside the wagon, the relation between the two speeds v1 and v2 is :
Consider the following statements:
1. Distance between the longitudes becomes zero on North Pole and South Pole.
2. Distance between the longitudes is maximum on the Equator.
3. Number of longitudes is more than number of latitudes.
Which of the statements given above is/are correct?
One block of 2⋅0 kg mass is placed on top of another block of 3⋅0 kg mass. The coefficient of static friction between the two blocks is 0⋅2. The bottom block is pulled with a horizontal force F such that both the blocks move together without slipping. Taking acceleration due to gravity as 10 m/s2, the maximum value of the frictional force is :
