You might have heard of carburettors and fuel injection systems on a motorcycle. Motorcycle terminology can be pretty tricky, as it has been for most of the automobile industry. Naturally, you might have also wondered which one of these is better and which one you should choose. Should you change from your primitive carburettor to the “new” fuel injection system? Let’s look at these two systems, compare them and find out which one is better.
A carburettor is a device that mixes air and fuel in an ideal “stoichiometric” ratio of air to the power of 14.7:1 for internal combustion engines. The carburettor aims to achieve this perfect ratio at all times for maximum performance; for this, a predefined finite volume of fuel is sent to the engine. It does not account for the speed of the motorcycle, the terrain, or any other factor. Thus, the volume of the mixture stays the same throughout its runtime. However, since a carburettor has many mechanical components working to function correctly, it always has some inefficiency that cannot be eradicated.
Twisting the motorcycle throttle handle does not directly control the amount of fuel allowed into the engine; instead, it contains the amount of air allowed into the machine. Based on Bernoulli’s principle, the Venturi effect states that when air flows through a restriction restricting pipe or tube, the airspeed increases, and air pressure decreases consequently. This pressure drop creates a suction effect that draws fuel from the carburettor bowl and the cylinder head. The mixture then undergoes combustion in the engine to produce power and torque, which drives the vehicle, or in this case, motorcycle. While carburettors can differ slightly in mechanisms, this is the basic gist of it.
Fuel Injection (FI)
A fuel injector is a device that sends necessary fuel into the engine using electronic controlled valves for optimum combustion, which optimizes efficiency. This process as a whole is known as fuel injection. Unlike carburettors, the fuel sent by fuel injection is variable depending on the motorcycle’s speed, the terrain or other factors. This essentially saves energy because, unlike carburettors, constant fuel isn’t being spent for maximum power when it isn’t needed. Fuel injection relies on an electrical device known as the ECU, which determines the amount of fuel necessary at any given time.
The ECU performs calculations received from multiple sensors around the bike to determine the amount of required fuel. These sensors are generally classified as crank position sensor, oil temperature sensor, throttle position sensor, atmospheric pressure sensor, intake air pressure sensor, and speed sensor. Readings from across all sensors are gathered and sent to the ECU, then the ECU performs calculations and determines the amount of fuel that should be injected in real-time.
Now that we know about carburettors and fuel injection, how do they differ from each other?
For starters, fuel injection provides superior fuel economy. This is due to constant regulation of the amount of fuel being used and the lack of inefficiency caused by mechanical parts, and something fuel injection does not rely on. This also means you can get more mileage out of your bike with fuel injection.
Next, performance is always guaranteed as fuel injection aims to administer necessary fuel without compromising performance. You might have failed to start your bike after a long time or after it’s gone cold for a while. This is because when the engine is cold, fuel vaporizes less readily and tends to condense on the walls of the intake manifold, starving the cylinders of power and making the engine difficult to start. So additionally, the FI engine doesn’t suffer through the temperature problem carburettors do.
Emissions are also significantly lower from fuel injections than carburettors, which are very eco-friendly. We live in times where environmental concerns are getting bigger day by day, and fuel resources are scarce. While stopping vehicles altogether isn’t a practical solution, switching to more efficient alternatives helps make up for it to a certain extent.
Our neighbouring country, India, has already adopted cleaner Euro VI-compliant fuels. Because Nepal imports all its petroleum products from India, we will be forced to follow suit regardless of choice. Thus, it’s better to adopt fuel injection and get acquainted with it sooner rather than later.
Fuel injection systems are more expensive than carburettors; however, they are also built to last longer. This means your fuel injection system will save more money than a carburettor in the long run when considering the maintenance costs.
Cars started using fuel injections quite some time before motorcycles. Installing fuel injection systems in motorcycles would skyrocket motorcycle prices and scare away potential buyers. However, through time and research, motorcycles finally got a viable way of using fuel injection. Other countries switched from carburettors to fuel injection decades back because of better environmental awareness and policies. As environmental concerns grow daily and we need to transition to healthier alternatives, Nepal also needs to switch to FI engines.
Besides, it’s not like Nepal has good pitch-black roads throughout the country. Riding on rough and uneven terrain in the carburettor system means you will be wasting fuel in the long run. You can do your pocket and the planet favour by switching to a fuel injection system.
Carburettors are still preferred by their more devout fans who like to work with mechanical parts and love dealing with motorcycle equipment. However, if you are not an enthusiast and only seek the better option, the wise choice will be to opt for fuel injection.