To combat growing pollution, India has transitioned from Bharat Stage IV (BSIV) to Bharat Stage VI (BSVI) emission standards from April 1, 2020. The mechanical changes to two-wheelers or bikes are significantly more severe as the transition from BS4 to BS6 emission requirements is so strict. Because the BS6 emission standards are so stringent, precise fueling is essential. Most motorcycle manufacturers have moved away from the less expensive carburetor and toward a more precise, but more expensive fuel-injection system.


Difference between Carburetor and fuel injection system

Automobile engineers have struggled to discover efficient ways to feed air and fuel to the combustion engine since the invention of the internal combustion engine. A carburetor is a device that adjusts the ratio of air-fuel mixture entering the engine; a fuel injection system does the same.

A carburetor, in simple terms, aids the entry of the air-fuel mixture into the combustion chamber. All of this is accomplished by mechanical components. The fuel injection system also aids the combustion chamber in obtaining an air-fuel mixture, but using electronics and sensors rather than mechanical components.


How Does a Carburetor Engine Work?

A carburetor’s sole or major function is to mix gasoline and air in a specific ratio and feed it to the combustion chamber. The device intercepts the airflow to the combustion chamber, mixes the fuel, and feeds it to the engine. When the bike’s throttle is pressed down, the airflow to the carburetor rises, generating suction of air and an increase in fuel delivery, resulting in higher acceleration.

Consider the carburetor to be a tube that regulates, or rather restricts, fuel flow in order to improve air velocity. The Venturi is the part that restricts the flow of fuel. With an increase in air velocity, a low-pressure area is produced, making it easier to draw fuel from a jet near the venturi. This results in a mixture of air and fuel that burns inside the combustion chamber. The Vacuum Venturi Effect is what this is called.


Carburetor Advantages:

While fuel injection systems have mostly supplanted carburetors, carburetors offer their own set of advantages. The benefits are as follows:

  • They’re less expensive, and they’re simple to fix or replace.
  • Users can fine-tune the carburetor to meet their specific needs, such as increased power or increased mileage.
  • As they are made of light materials, they are often long-lasting.
  • As they are independent from the engine, they may be readily removed and maintained or changed without causing damage to the engine.


Carburetors have been phased out in favour of fuel injection systems for a variety of reasons. The following are some of the downsides of a carburetor:

  • As a fuel injection system, it is inefficient.
  • The throttle body has a certain amount of lag, resulting in a delayed response.
  • Parts of carburetors are prone to wear and damage, necessitating periodic repair.
  • The air-fuel mixture ratio may not always be the same and must be adjusted on a regular basis.
  • There’s a chance that dust will get into the carburetor chamber and cause obstructions.
  • Diaphragm components are sensitive and susceptible to damage.


How Does Fuel Injection System Work?

A complicated mix of electronic components and sensors make up the fuel injection system. The flow of fuel to the combustion chamber is controlled by a fuel pump in the system. This fuel pump is positioned inside the motorcycle’s fuel tank. An Electronic Control Unit allows fuel to be delivered to the combustion chamber (ECU). This electric brain is continually monitoring and doing sophisticated calculations to ensure that the finest possible air-fuel mixture is delivered. Fuel injection is a technology that eliminates the need for carburetors in automobiles. The technology enables the engine to provide gasoline directly to the cylinder in the intake manifold, or to put it another way, it delivers fuel to the engine directly.

The complicated computations take into account things like throttle position, engine speed, temperature, and load, among other things. The fuel injection system’s nozzle enters the cylinder chamber directly. As a result, the ECU instructs the injectors to manage the amount of fuel so that the most efficient mode of combustion can be achieved.


Types of fuel injection system

1. Throttle Body Injection or Single-Point Injection:

The single-point kind of injection system is the earliest and simplest fuel injection technology that replaces carburetors. The throttle body, which is the throat of the engine’s air intake manifold, has one or two injector nozzles.

This injector system is not as accurate as the one that came after it, but it has better control, is less expensive, and is easier to service when compared to carburetors.

2. Multiport Fuel Injection:

Separator injector nozzles are contained in each cylinder’s intake port in multiport fuel injectors. This is why the technique is sometimes referred to as a port injector: the fuel vapour is shot near to the intake point, ensuring that it is entirely pulled into the cylinder.

When compared to a single point, one of the advantages of this injector is that it metres gasoline more precisely. It’s also ideal for achieving the needed fuel-to-air ratio and essentially minimises the chance of gasoline condensing or collecting in the intake manifold.

3. Sequential Fuel Injection:

It is also commonly known as sequential port fuel injection or time injection, is a type of fuel injector. Even though simple multiport injection uses numerous injectors, it is a form of multiport injection. When the engine is idling, they all spray their fuel at the same time or consecutively, causing the gasoline to stay around for up to 150 milliseconds.

Sequential fuel injection has the advantage of allowing the system to respond more quickly if the driver makes an abrupt change. This is due to the fact that the valve just needs to wait for the next intake valve to open, rather than the entire engine revolution.

4. Direct injection:

Direct injection is popular in diesel engines, but it is becoming more frequent in gasoline engine designs. Direct-injection gasoline (DIG) is another name for it. Fuel is pumped directly into the combustion chamber, bypassing the valves, in this method.

Fuel metering is more accurate than other forms of fuel injection. Engineers now have another variable to control how combustion occurs in the cylinders: direct fuel injection. Engine design science looks at how the air-fuel mixture swirls around in the cylinders.


Benefits of Fuel Injection:

The following are some of the benefits of using a fuel injection system on a motorcycle:

  • Accurate atomization and air-fuel mixture.
  • Combustion that is cleaner and more efficient.
  • Throttle response is sharper and faster.
  • Better mileage or fuel efficiency.
  • FI systems are less prone to damage and require less maintenance than carburetors.
  • ECU mapping allows for easy tuning.


Fuel Injection System Drawbacks:

Fuel injection systems do have some drawbacks. Here are a few of the cons of FI:

  • When compared to traditional carburetors, they are more expensive.
  • Complex tools are required to optimise the FI system via bespoke ECU mapping.
  • Repairing it necessitates the use of expensive tools, resulting in higher expenditures.
  • The bike will not start if the ECU fails, and you may be left stranded.

Comparison between a carburetor and a fuel injection engine?

When comparing carburetor vs. fuel injection in motorcycles, you might be asking which is superior. Some of the distinctions between the two are listed below:

  • Versatility: Carburetors are phased out since they are comparatively more pollutant compared to FI systems.
  • Performance: The ECU is continually doing sophisticated calculations in order to provide the optimal engine performance. When it comes to constantly changing fuel temperature and air pressure, carburetors suffer.
  • Mileage: Because the FI system accurately measures fuel and air, the engine performs better, resulting in greater fuel management and mileage. If you need a greater power ratio, the ECU can be remapped.
  • Maintenance: The carburetor is the only category where it outperforms the fuel injection system. Carburetors are simple to fix or replace, whereas FI systems necessitate professional assistance, which might result in greater expenditures.


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