Carburettor Vs Fuel Injection: Differences & Working Mechanism
With the progress of mechanisms in automobiles, fuel injection systems are gradually winning over carburettor systems for several reasons. Both systems are responsible for passing the air-fuel mixture properly to create perfect pressure during engine combustion.
However, there are sharp differences between carburettor and fuel injection systems. Keep reading to find out.
What Is a Carburettor?
Definition: A carburettor is a device inside the engine that mixes oil and air in perfect ratio during an engine combustion process. The mechanism provides spark ignition to the engine. The components of a carburettor are:
- Venturi
- Idling System
- Throttle Valve
- Strainer
- Idle and Transfer port
- Choke Valve
- Float Chamber
- Mixing Chamber
Types: Carburettors are of two types, fixed venturi and variable venturi. Fixed venturi carburettors regulate the fuel flow with a velocity of airflow. On the other hand, variable venturi controls the raw fuel mechanically and regulates fuel flow with airflow.
Materials: A carburettor has many parts to perform the engine combustion task. Therefore, different parts are made with different materials. However, the main part of a carburettor is made with alloy or aluminium, essentially lightweight. Further, other moving parts are made with stainless steel.
How Does a Carburettor Work?
A carburettor is situated between the inlet and induction manifold and compiles air pressure and oil for engine ignition. The working process of a carburettor is as follows:
Step 1: A charged engine forces air into this carburettor
Step 2: In the middle of a carburettor, a venturi, a pipe-like construction restricts this air and increases its velocity
Step 3: The increasing velocity creates a low-pressure pocket that, in turn, helps draw fuel from a nearby jet to the venturi by suction
Step 4: At the end of the venturi, a butterfly valve controls and regulates the air pressure of the pipe
Step 5: Butterfly valve works with a throttle valve that controls fluid flow
Step 6: As the throttling process moves forward, the mixture of air and fluid enters the induction manifold, and combustion happens
What Is Fuel Injection?
Definition: Fuel injection is an important mechanism that helps in low fuel consumption. It is common in automotive engines in the form of a fuel injector. Therefore, it is an electronically-regulated system that injects a minimum amount of atomised fuel into the cylinder. The components of fuel injection are:
- Fuel tank and supply pump
- Fuel heaters and coolers
- Fuel filter
- Accumulator
- High-pressure pump
- Fuel injector and fuel injection nozzle
- Fuel metering
- Nozzle needle control actuators
Types: There are four types of fuel injection; throttle body or single-point injection, multipoint fuel injection, direct injection, and sequential fuel injection. A single-point injection is the most basic fuel injection and just a replacement for a carburettor.
A multipoint fuel injector injects fuel into each cylinder with different injector nozzles. The direct fuel injection allows diesel and petrol engines to utilise fuel more efficiently, thereby leading to more power. Lastly, sequential fuel injection is an advanced form of multiport fuel injector that works for efficiency and emission improvements.
Material: Fuel injectors are made with carburised or maraging steel to manage high temperatures.
How Does Fuel Injection Work?
Fuel injection is monitored electronically; therefore, it calculates and gives the most efficient air-fuel mixture and is responsible for a smooth and clean combustion process. A fuel injection system works in the following process,
Step 1: A fuel pump draws the fuel from the tank with superb control
Step 2: This atomised fuel enters the combustion chambers as FI mist through nozzles
Step 3: as it reaches the chamber, combustion happens
What Are the Differences Between Carburettor and Fuel Injection?
| Parameters | Carburettor | Fuel injection |
| Efficiency | Does not provide efficiency as it is quite outdated. | Highly efficient for electronic monitoring methods. |
| Cost | Carburettors are cheaper. | A fuel injection system is quite expensive. |
| Repair and replacements | A carburettor is easy to repair and replace without even touching the engine. | Fuel injection repair and replacement involve complex processes and are quite costly too. |
| Throttle response | It has a low throttle response. | It has a high throttle response. |
| Durability | Some parts of a carburettor are delicate and lack durability. | Components of fuel injectors are less prone to damage. |
| Air-fuel mixture efficiency | As it is mechanically controlled, the proportion fluctuates. | Due to its electric power, it is more efficient in maintaining a right proportion of air and fuel |
| Engine combustion | Due to ill proportionate mixture, combustion disrupts sometimes. | Gives better and smooth combustion of its advanced technology. |
So the above differences between carburettor and fuel injection will help you to understand the working process of these two systems.
Further, this article discusses the idea of a fuel injection system vs a carburettor that clearly shows the comparison of the efficiency of these two systems. However, electronic fuel injection has recently been widely popular for its effectiveness and better service.
Frequently Asked Questions
What are the tell-tale signs of carburettor problems?
You will come across the following issues in case of carburettor malfunctions:
- The engine simply doesn’t start and keeps cranking.
- The engine either runs “lean” or “rich.”
- Fuel overflows into the carburettor.
Which cars have fuel injectors?
All cars after 1990 mostly have fuel injectors for engine combustion. Petrol cars use indirect fuel injectors, while diesel cars have direct ones. Fuel injection is the most efficient engine combustion system that outdates its carburettor system.