An engine consumes fuel to produce energy for a car to function. Car engines of modern vehicles in India commonly use fuel such as petrol, diesel, CNG and LPG.

In petrol engines, petrol or gasoline is ignited in the internal combustion engine, where it combines with air to produce energy that turns the wheels. This blog aims to discuss the fuel supply systems in petrol engines.

The fuel supply system in a petrol engine comprises various components that work together to transfer a set amount of fuel from a car’s fuel tank to its engine for combustion. These components include a fuel tank, fuel pump, carburettor, fuel injectors, fuel filters and fuel lines.

The primary function of this system is to store and supply fuel for the engines. Petrol gets drawn from the tank through fuel lines to the injector by fuel pumps. The fuel injection system pumps the required fuel to a car’s engine for combustion.

1. Gravity system

The manufacturers mount the fuel tank at the spark-ignition engine's highest point in this fuel system. Petrol drops into the carburettor from its highest position due to gravity. The mechanisms of this fuel system are quite simple and extremely inexpensive. Therefore, one can find gravity systems in small engines with less fuel consumption. Moreover, manufacturers do not develop good heads for large engines.

Advantages:

• The gravity fuel system is cheaper than all other fuel supply systems.

Disadvantages:

• It causes rigidity when the manufacturers mount the petrol tank over the carburettor.

2. Pressure system

In this fuel system, car manufacturers place a pressure seal tank or an air-tight tank to neat a car's engine or under the seat. A pump creates pressure with the help of air and then pushes petrol towards the combustion chamber.

Advantages:

• Car manufacturers can choose to place the petrol tank in any suitable location.

Disadvantages:

• Pressure can leak anytime from air-tight enclosures within its chambers.

3. Pump system

A steel pipe is placed in this fuel supply system, and its job is to carry petrol to the fuel pump. This fuel pump then pumps petrol into the float chamber inside the carburettor through another steel pipe. Nowadays, mechanical, electrical, and diaphragm pumps supply petrol from the fuel tank.

Advantages:

• This system can be easily used for all types of vehicles, from trucks and buses to cars.

Disadvantages:

• Placing a fuel pump is essential for these systems because, without the help of the pump, the petrol will not move. However, this increases the overall cost.

4. Fuel Injection System

This fuel supply system is most prevalent in modern cars. In this system, the air injector nozzle atomises fuel from the petrol tank and sends these particles into the air stream. Manufacturers sometimes use separate injectors for each cylinder or just one for all the cylinders.

Advantages:

• Fuel injection systems are advanced, and, as a result, they are the most accurate among all other systems.
• Such systems can quickly warm up and start a car’s engine.
• Fuel injection system enables engines to develop high power.
• These consume less petrol in certain instances.

Disadvantages:

• Setting up this fuel supply system can be quite expensive initially.
• In some cases, petrol backflows can occur.

1. Fuel Tank

A car's fuel tank holds and stores fuel in place for a car to run. In cases where a petrol tank is leaking or clogged, petrol will not be able to travel smoothly to the combustion chamber. Therefore, the proper functioning of this part of a vehicle is essential because it helps in the smooth functioning of the vehicle.

2. Fuel Pump

The fuel pump's job is to take petrol from the fuel tank and transfer it to fuel injectors. It takes this fuel through fuel lines. A fuel pump is present only in petrol engines, whereas, in diesel engines, the injector directly sends petrol to a car's carburettor. Furthermore, there are two types of fuel pumps the first is the mechanical pump and the second is the electrical pump.

3. Fuel Injector

A fuel injector's function is to inject fuel into a carburettor or a car's combustion chamber. This component is a valve with a long nozzle that generates fuel sprays and air droplets.

4. Carburettor

You will find carburettors mostly in older petrol engines. A carburettor creates an air and fuel mixture after the fuel injector transfer petrol. Then, after it has completely mixed fuel and air from the environment, it sends the mixture to a car's combustion chamber.

5. Fuel Filter

A fuel filter plays an important role inside a petrol engine. Fuel injectors are not very durable, which is why they get damaged easily due to debris and fuel particles. The fuel filter's job is to suck these debris and fuel particles from the tank and pump. It is installed between the pump and the tank to catch these particles.

6. Fuel Lines

The fuel lines create a bridge between all the other components present in the fuel supply system in petrol engines. It links the petrol tank to the fuel injector and the engine tank to the engine.

7. Fuel Gauge

The fuel gauge is a dial that shows the amount of petrol that is still in a vehicle's fuel tank. You can easily find it on the dashboard of your car. In older cars, the fuel gauge did not always show the actual amount of fuel in the car's tank, but in modern cars, the representation is pretty accurate.

8. Emission Vapour Control System

The emission vapour controls' job is to stop the petrol vapours from getting discharged in the vehicle's ambient air. If this component malfunctions, it can lead the bad odour inside the vehicle. Moreover, it is also harmful to the environment and can cause problems in the engines' overall well-being.

9. Fuel Pressure Regulator

The fuel pressure regulator maintains proper pressure in a car's engine. It is present in petrol engines, so fuel injectors have more pressure than combustion chambers.

Now that you know all the components of a fuel supply system for petrol engines let us learn about the various supply systems.

Before knowing various types of fuel supply systems that transfer petrol or any other kind of fuel to a car's engine, one must know about various components that determine the fuel's quality. These determining factors are as follows:

• Volatility- Petrol's volatility is an important determining factor because it will affect the performance of your vehicle's engine. Furthermore, the volatility of fuel also affects some other factors:

  • The ease at which drivers can start their vehicle
  • Vapour lock forming in a fuel supply system
  • Acceleration of a car’s engine
  • Percentage of crankcase oil dilution
  • Circulation of petrol in a multi-cylinder engine
• Ignition Quality- This term refers to the ease at which oil can burn in a vehicle’s combustion chamber. Moreover, experts use octane and cetane number to determine petrol’s ignition quality. Both octane and cetane evaluate a car fuel’s knock characteristics.
• Calorific Value- When petrol causes combustion, it produces heat in a car's engine, which is called fuel's heat or calorific value. Calorific value is essential because it helps measure petrol quality as this heat makes an engine work.

Fuel supply systems in petrol engines can be of many types. Having a general idea about your car’s fuel supply system will help you in case it malfunctions, and you have to decide whether to take it to a garage to fix the problem or it can be fixed at home.