Fuel injection is now almost replaced carburation in Spark Ignition engines.Which system of the two is more simple to handle and maintain, saves fuel and inexpensive?
- More accurate air-fuel mixture preparation in all points of operation.
- ... in this way possibility of stocheometric air-fuel ratio (Lambda=1) operation, which is required for 3-way catalyst exhaust gas after treatment.
- Possibility to apply factors for transient operation conditions (e.g. accelleration and decelleration behavior).
- Possibility to compensate temperature and air pressure effects (e.g. cold start conditions, high altitude operation).
- No carburettor nozzle and hole coking, no carburettor icing.
Kind regards,
Mario
Thank you Mario. But the injector itself have nozzles also, aren't they subjected to clogging by carbon or other particles? Do they need cleaning every now and then?
In general, yes, but in comparison with carburettor, the probability of clogging is much lower, because of much lower content of fuel in the injection nozzle, and forced pressure by the fuel pump. In carburettors, there is a floating chamber, which is filled with fuel, and there are several (small) holes and nozzels, which are subject of clogging. Fuel pressure is much lower than in an FI-system, because the fuel is forced into the intake tube by venturi effect (low pressure condition effect).
Kind regards,
Mario
Carburation is cheaper but less efficient. Fuel injection is not only more efficient and reliable but far more controllable, thanks to modern electronic control systems that enable multiple microbursts during induction. Injector clogging is avoided by proper filtration and deposit build-up over time is avoided with fuel additives. Gasoline (petrol) is also produced to much higher standards of cleanliness these days.
Atmospheric temperature and pressure play a major role in the carburetion process (choking) but the fuel injection process is not much influenced by these properties. Also, carburettor is less efficient during low engine rpm. It is also affected by inertia, while the vehicle is taking a turn and during steep climbs. All these can be avoided by using the fuel injection system, which can control the fuel consumption by supplying the accurate quantity of air-fuel mixture based on the acceleration requirement. The only disadvantage of injection is high cost when compared to carburetion.
Fuel injection is efficient and safe fuel but it is expensive then carburetor but for the maintenance perspective in fuel injection system more skilled labour is required as it is controlled by electronic control unit as compared to carburetor which is based on venturi duct.
Fuel injection allows precise fuel metering, which increases efficiency. Maintaining a stoichiometric is necessary for the operation of a three-way catalyst, which destructs most of the harmful emissions. In regions where quality fuel is used, there are rarely any clogging or other problems.
On automobiles, fuel injection is more economical, as the fuel savings outweigh the additional cost and complexity.
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