Fuel injection systems and how to maintain them

What is Fuel Injection?

Fuel injection system is mainly responsible for the introduction of fuel into an internal combustion engine. In the western world, fuel injection system has replaced the carburetor system during the 90s.The main difference between the carburetor system and the fuel injection system is in the physical state of the fuel in which it enters the combustion chamber, carburetor pushes fuel which is still in the liquid state whereas the injection system atomizes it which in turn produces better combustion. There are more than one type of injection system which will be discussed later.

Different types of fuel injection:

Single point fuel injection: In single point injection system the fuel is sprayed into the throttle body of the engine. It is the same location where fuel is pushed by the carburetor. Injected fuel is then sucked due to the suction motion of alternate cylinders during the suction stroke and performs combustion. Such a system is called “Wet manifold system”. This system was equipped in some earlier models of Honda, Ford, Mazda and many others.

Continuous fuel injection: In this system the fuel flows continuously but with a variable rate unlike the single point injection system which provides fuel in a pulsating manner. This system was introduced in 1974 by Bosch and came under the name tag of “K-jetronic”. This system was instantly adopted by various famous brands such as Ferrari, Benz, Volkswagen, Ford, Porsche e.t.c.

Central port fuel injection: This system was introduced by General Motors. The system uses tubes which go from the central injection system to individual intake points of each cylinder. The tubes are equipped with poppet valves which supply fuel in pulsating manner.

Multiport fuel injection: Multiport fuel injection system provides fuel at the intake point of each cylinder unlike the central injection system. There are two sub-types of this system which are known as sequential and batched. In sequential system fuel is provided at the time of intake of every cylinder whereas in the batched system the fuel is provided in groups.

Direct fuel injection: In this system the fuel is sprayed directly into the combustion chamber rather than the intake manifold or the throttle body which then sucks it into the combustion chamber. The injectors of this system are exposed to more heat and pressure, so more costly and high end materials are required for their production

Systems of local cars:

Toyota Corolla 2012 onwards:

From 2012 onwards Toyota has incorporated two separate systems for the 1.8 L and the other variants. The 1.3 L comes with SOHC VVTI engine equipped with multiport fuel injection whereas the 1.8 L variant comes with Dual VVTI and direct fuel injection.

Honda civic 2002-2005:

Similar to the Corolla, Civics are equipped with SOHC VTEC multiport fuel injection system. Four injectors are present which serves the four inline cylinders of the D-series engine.

Toyota Vitz:

The Vitz with 1NR-FE engine comes with 16 valves DOHC Dual VVTI system, sequential fuel injection system. Four injectors for four cylinders.

Injector maintenance:

Most the manufacturers recommend to clean the injectors at around 40,000 miles but due to the lack of knowledge of our local mechanics and even the authorized service centers don’t know anything about the system for most of the times. We should avoid using high octane fuel with these local vehicles because their engines are not designed to handle the high octane rating fuel. If it is really necessary to clean out the injectors of your ride then use injector cleaning chemicals or fuel additives which clean the injectors while they pass through them, this is a pretty easy and effective way. Another one is the hardcore method in which you have to take out the injectors and then use some of the cleaning kits available in the market to clean them. Make sure that your fuel tank is clean because the residual buildup in the tank will eventually end up in clogging your car’s precious injectors. There is a new method in the market to clean the injectors where they dip the injectors in some sort of chemical cleaner for adequate time which cleans them out, known as Ultra sonic cleaning.

I can’t cover the specifications of all the cars but the mechanism of almost all the cars is same due to which the above mentions maintenance method can be applied to almost all vehicles.