All engines need to have some source of energy (fuel), whether that energy is electricity, gasoline, hydrogen or some other source. Because vehicles contain engines, they all need such sources of energy. If the power source is a liquid fuel such as gasoline, vehicle design generally requires a method of getting the liquid fuel from the gasoline tank to the carburetor and fueling the system. In most vehicles, this method is the fuel pump. Because there are different types of fuel pumps, the following sections list each one, explain the differences, and talk a bit about where they can be found.
Mechanical pumps
Mechanical fuel pumps are one of the two most important types of fuel pumps. These pumps are used in engines with carburettors. They are called mechanical pumps because they operate mechanically – for example, their operation depends on the turning of a cam rod, which manipulates a lever that pulls a diaphragm that operates valves that allow fuel to escape out of the tank and into the fuel system. . These pumps are low pressure and operate as low as 4-6 psi. They are generally mounted on the engine.
Electric pumps
Electric fuel pumps are the second main type of fuel pumps. They are used in engines with fuel injection systems. These pumps do not require an eccentric cam on a cam rod to operate, and can operate at much higher pressures than mechanical fuel pumps. Most electric fuel pumps operate between 30 to 40 psi. In fact some fuel injection systems make use of two electric fuel pumps. One is tank mounted and the other is mounted on or near the engine.
Turbo pumps
A third type of fuel pump is less well known because it is located only in jet and rocket engines. These pumps are called turbo pumps. They are centrifugal and get their propulsion from either an air blower or a gas turbine.
Security
Of the two main types of fuel pumps, electric ones are considered the safest. This is because they generally make use of two separate devices. The first device is an electronic control unit (ECU) that is designed to stop pump operation in the event of an accident. The second device is an inertia switch. This switch prevents the pump from operating if it feels like the vehicle has overshot. In addition, placing the electric fuel pump inside the gas reduces the risk of fire because liquid gasoline is less flammable than gasoline in vapors.
Pros and cons
There are pros and cons to both main types of fuel pumps. Hand pumps can be easier and cheaper to replace than electric fuel pumps because electric pumps have different components and are submerged in gasoline. However, electric fuel pumps are more efficient than mechanical pumps due to their ability to operate at high pressures; And, because the standard type of fuel pumps are becoming the standard, the correct electric fuel pump may be easier to find if it needs to be replaced than a mechanical pump would be.
