A fuel pump transports gasoline from the tank to the vehicle’s engine using a fluid conveyance system. Internal combustion engines are the most commonplace to find it. The carburettor in spark-ignition engines is responsible for mixing gasoline and air before being delivered to the combustion chamber.
High-pressure fuel pumps deliver fuel directly to the combustion chamber for maximum combustion efficiency in combustion ignition engines. High-pressure air is already present in combustion ignition engines at the time of combustion. As a result, for ignition to occur, the fuel pump must deliver fuel to the combustion chamber at a pressure more significant than the chamber’s own.
There are three primary types of gasoline pumps on the market, and you’ll go through each one in turn: –
1. Mechanical fuel pumps:
Fuel is transferred from the tank to the spark-ignition engine’s fuel bowl using low-pressure fuel pumps. High-pressure versions are also sometimes utilised. A Diaphragm-type and plunger-type mechanical fuel pump are two types of mechanical fuel pumps.
- Fuel Pump with Diaphragm
Positive displacement pumps, such as the diaphragm type, draw gasoline in by expanding and compressing the diaphragm. One-way valves are located at the inlet and outlet of the pump. Fuel is pulled into the pump when the diaphragm closes, lowering the pump’s pressure to a level lower than the surrounding air. The gasoline in the pump is forced out of the exit valve when the diaphragm expands. Diaphragm expansion and contraction are regulated by a lever that moves in response to an eccentric cam movement. This eccentric cam is coupled to the engine’s crankshaft through a correct gearing arrangement.
- Fuel Pump with a Plunger
The reciprocating action of the plunger is used to suck and discharge gasoline in the plunger-type positive displacement fuel pump—pushrods on both sides of the plunger link to the camshaft, housed in a separate cylinder. The cylinder’s tip is where the valves are located. When the plunger is in a backward motion, the fuel is drawn into the cylinder, and during the forward motion of the plunger, the fuel is delivered out of it.
Although the mechanical pumps supply gasoline at a steady pressure, they require regular maintenance due to the many moving parts. These pumps have become outdated due to the shift from carburettors to fuel injection systems in today’s automobiles.
2. Electric fuel pumps
A critical component of contemporary automobiles, fuel injection systems commonly employ these pumps. It raises the pressure to deliver more fuel. The gasoline inside the pump may burn due to the excessive pressure, which might cause the explosion. As a result, electric gasoline pumps should be kept out of reach of the engine, preferably within the fuel tank, for safety reasons.
The vehicle’s battery provides the power needed to run the fuel pump. An electronic control unit (ECU) also regulates the fuel’s output pressure and volume and appropriately measures the gasoline entering the tank. As a result, the ECU improves the vehicle’s mileage and power.
3. High-Pressure fuel pumps
These pumps are often employed in combustion ignition engines to inject fuel into the combustion chamber directly. Above 200 Pascals, these pumps are used. Pump systems designed to manage such high pressures are often complicated and robust in design. Flow rails, metres, and other components of the high-pressure pump system assist the pump in delivering gasoline to the combustion chamber efficiently and without wasting or over-fueling.